SUNRPC: add a missing rpc_stat for TCP TLS

Commit 1548036ef120 ("nfs: make the rpc_stat per net namespace") added
functionality to specify rpc_stats function but missed adding it to the
TCP TLS functionality. As the result, mounting with xprtsec=tls lead to
the following kernel oops.

[ 128.984192] Unable to handle kernel NULL pointer dereference at
virtual address 000000000000001c
[ 128.985058] Mem abort info:
[ 128.985372] ESR = 0x0000000096000004
[ 128.985709] EC = 0x25: DABT (current EL), IL = 32 bits
[ 128.986176] SET = 0, FnV = 0
[ 128.986521] EA = 0, S1PTW = 0
[ 128.986804] FSC = 0x04: level 0 translation fault
[ 128.987229] Data abort info:
[ 128.987597] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[ 128.988169] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[ 128.988811] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[ 128.989302] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000106c84000
[ 128.990048] [000000000000001c] pgd=0000000000000000, p4d=0000000000000000
[ 128.990736] Internal error: Oops: 0000000096000004 [#1] SMP
[ 128.991168] Modules linked in: nfs_layout_nfsv41_files
rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace netfs
uinput dm_mod nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib
nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct
nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 rfkill
ip_set nf_tables nfnetlink qrtr vsock_loopback
vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vsock
sunrpc vfat fat uvcvideo videobuf2_vmalloc videobuf2_memops uvc
videobuf2_v4l2 videodev videobuf2_common mc vmw_vmci xfs libcrc32c
e1000e crct10dif_ce ghash_ce sha2_ce vmwgfx nvme sha256_arm64
nvme_core sr_mod cdrom sha1_ce drm_ttm_helper ttm drm_kms_helper drm
sg fuse
[ 128.996466] CPU: 0 PID: 179 Comm: kworker/u4:26 Kdump: loaded Not
tainted 6.8.0-rc6+ #12
[ 128.997226] Hardware name: VMware, Inc. VMware20,1/VBSA, BIOS
VMW201.00V.21805430.BA64.2305221830 05/22/2023
[ 128.998084] Workqueue: xprtiod xs_tcp_tls_setup_socket [sunrpc]
[ 128.998701] pstate: 81400005 (Nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[ 128.999384] pc : call_start+0x74/0x138 [sunrpc]
[ 128.999809] lr : __rpc_execute+0xb8/0x3e0 [sunrpc]
[ 129.000244] sp : ffff8000832b3a00
[ 129.000508] x29: ffff8000832b3a00 x28: ffff800081ac79c0 x27: ffff800081ac7000
[ 129.001111] x26: 0000000004248060 x25: 0000000000000000 x24: ffff800081596008
[ 129.001757] x23: ffff80007b087240 x22: ffff00009a509d30 x21: 0000000000000000
[ 129.002345] x20: ffff000090075600 x19: ffff00009a509d00 x18: ffffffffffffffff
[ 129.002912] x17: 733d4d4554535953 x16: 42555300312d746e x15: ffff8000832b3a88
[ 129.003464] x14: ffffffffffffffff x13: ffff8000832b3a7d x12: 0000000000000008
[ 129.004021] x11: 0101010101010101 x10: ffff8000150cb560 x9 : ffff80007b087c00
[ 129.004577] x8 : ffff00009a509de0 x7 : 0000000000000000 x6 : 00000000be8c4ee3
[ 129.005026] x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff000094d56680
[ 129.005425] x2 : ffff80007b0637f8 x1 : ffff000090075600 x0 : ffff00009a509d00
[ 129.005824] Call trace:
[ 129.005967] call_start+0x74/0x138 [sunrpc]
[ 129.006233] __rpc_execute+0xb8/0x3e0 [sunrpc]
[ 129.006506] rpc_execute+0x160/0x1d8 [sunrpc]
[ 129.006778] rpc_run_task+0x148/0x1f8 [sunrpc]
[ 129.007204] tls_probe+0x80/0xd0 [sunrpc]
[ 129.007460] rpc_ping+0x28/0x80 [sunrpc]
[ 129.007715] rpc_create_xprt+0x134/0x1a0 [sunrpc]
[ 129.007999] rpc_create+0x128/0x2a0 [sunrpc]
[ 129.008264] xs_tcp_tls_setup_socket+0xdc/0x508 [sunrpc]
[ 129.008583] process_one_work+0x174/0x3c8
[ 129.008813] worker_thread+0x2c8/0x3e0
[ 129.009033] kthread+0x100/0x110
[ 129.009225] ret_from_fork+0x10/0x20
[ 129.009432] Code: f0ffffc2 911fe042 aa1403e1 aa1303e0 (b9401c83)

Fixes: 1548036ef120 ("nfs: make the rpc_stat per net namespace")
Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Add a transport callback to handle dequeuing of an RPC request

Add a transport level callback to allow it to handle the consequences of
dequeuing the request that was in the process of being transmitted.
For something like a TCP connection, we may need to disconnect if the
request was partially transmitted.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Don't retry using the same source port if connection failed

If the TCP connection attempt fails without ever establishing a
connection, then assume the problem may be the server is rejecting us
due to port reuse.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Remove stale comments

bc_close() and bc_destroy now do something, so the comments are
no longer correct. Commit 6221f1d9b63f ("SUNRPC: Fix backchannel
RPC soft lockups") should have removed these.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

SUNRPC: Force close the socket when a hard error is reported

Fix up xs_wake_error() to close the socket when a hard error is being
reported. Usually, that means an ECONNRESET was received on a connection
attempt.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC/TLS: Lock the lower_xprt during the tls handshake

Otherwise we run the risk of having the lower_xprt freed from underneath
us, causing an oops that looks like this:

[ 224.150698] BUG: kernel NULL pointer dereference, address: 0000000000000018
[ 224.150951] #PF: supervisor read access in kernel mode
[ 224.151117] #PF: error_code(0x0000) - not-present page
[ 224.151278] PGD 0 P4D 0
[ 224.151361] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 224.151499] CPU: 2 PID: 99 Comm: kworker/u10:6 Not tainted 6.6.0-rc3-g6465e260f487 #41264 a00b0960990fb7bc6d6a330ee03588b67f08a47b
[ 224.151977] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 2/2/2022
[ 224.152216] Workqueue: xprtiod xs_tcp_tls_setup_socket [sunrpc]
[ 224.152434] RIP: 0010:xs_tcp_tls_setup_socket+0x3cc/0x7e0 [sunrpc]
[ 224.152643] Code: 00 00 48 8b 7c 24 08 e9 f3 01 00 00 48 83 7b c0 00 0f 85 d2 01 00 00 49 8d 84 24 f8 05 00 00 48 89 44 24 10 48 8b 00 48 89 c5 <4c> 8b 68 18 66 41 83 3f 0a 75 71 45 31 ff 4c 89 ef 31 f6 e8 5c 76
[ 224.153246] RSP: 0018:ffffb00ec060fd18 EFLAGS: 00010246
[ 224.153427] RAX: 0000000000000000 RBX: ffff8c06c2e53e40 RCX: 0000000000000001
[ 224.153652] RDX: ffff8c073bca2408 RSI: 0000000000000282 RDI: ffff8c06c259ee00
[ 224.153868] RBP: 0000000000000000 R08: ffffffff9da55aa0 R09: 0000000000000001
[ 224.154084] R10: 00000034306c30f1 R11: 0000000000000002 R12: ffff8c06c2e51800
[ 224.154300] R13: ffff8c06c355d400 R14: 0000000004208160 R15: ffff8c06c2e53820
[ 224.154521] FS: 0000000000000000(0000) GS:ffff8c073bd00000(0000) knlGS:0000000000000000
[ 224.154763] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 224.154940] CR2: 0000000000000018 CR3: 0000000062c1e000 CR4: 0000000000750ee0
[ 224.155157] PKRU: 55555554
[ 224.155244] Call Trace:
[ 224.155325] <TASK>
[ 224.155395] ? __die_body+0x68/0xb0
[ 224.155507] ? page_fault_oops+0x34c/0x3a0
[ 224.155635] ? _raw_spin_unlock_irqrestore+0xe/0x40
[ 224.155793] ? exc_page_fault+0x7a/0x1b0
[ 224.155916] ? asm_exc_page_fault+0x26/0x30
[ 224.156047] ? xs_tcp_tls_setup_socket+0x3cc/0x7e0 [sunrpc ae3a15912ae37fd51dafbdbc2dbd069117f8f5c8]
[ 224.156367] ? xs_tcp_tls_setup_socket+0x2fe/0x7e0 [sunrpc ae3a15912ae37fd51dafbdbc2dbd069117f8f5c8]
[ 224.156697] ? __pfx_xs_tls_handshake_done+0x10/0x10 [sunrpc ae3a15912ae37fd51dafbdbc2dbd069117f8f5c8]
[ 224.157013] process_scheduled_works+0x24e/0x450
[ 224.157158] worker_thread+0x21c/0x2d0
[ 224.157275] ? __pfx_worker_thread+0x10/0x10
[ 224.157409] kthread+0xe8/0x110
[ 224.157510] ? __pfx_kthread+0x10/0x10
[ 224.157628] ret_from_fork+0x37/0x50
[ 224.157741] ? __pfx_kthread+0x10/0x10
[ 224.157859] ret_from_fork_asm+0x1b/0x30
[ 224.157983] </TASK>

Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Allow specification of TCP client connect timeout at setup

When we create a TCP transport, the connect timeout parameters are
currently fixed to be 90s. This is problematic in the pNFS flexfiles
case, where we may have multiple mirrors, and we would like to fail over
quickly to the next mirror if a data server is down.

This patch adds the ability to specify the connection parameters at RPC
client creation time.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Refactor and simplify connect timeout

Instead of requiring the requests to redrive the connection several
times, just let the TCP connect code manage it now that we've adjusted
the TCP_SYNCNT value.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Set the TCP_SYNCNT to match the socket timeout

Set the TCP SYN count so that we abort the connection attempt at around
the expected timeout value.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Use new helpers to handle TLS Alerts

Use the helpers to parse the level and description fields in
incoming alerts. "Warning" alerts are discarded, and "fatal"
alerts mean the session is no longer valid.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/169047944747.5241.1974889594004407123.stgit@oracle-102.nfsv4bat.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

SUNRPC: Send TLS Closure alerts before closing a TCP socket

Before closing a TCP connection, the TLS protocol wants peers to
send session close Alert notifications. Add those in both the RPC
client and server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/169047939404.5241.14392506226409865832.stgit@oracle-102.nfsv4bat.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/tls: Move TLS protocol elements to a separate header

Kernel TLS consumers will need definitions of various parts of the
TLS protocol, but often do not need the function declarations and
other infrastructure provided in <net/tls.h>.

Break out existing standardized protocol elements into a separate
header, and make room for a few more elements in subsequent patches.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/169047931374.5241.7713175865185969309.stgit@oracle-102.nfsv4bat.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

SUNRPC: Add a TCP-with-TLS RPC transport class

Use the new TLS handshake API to enable the SunRPC client code
to request a TLS handshake. This implements support for RFC 9289,
only on TCP sockets.

Upper layers such as NFS use RPC-with-TLS to protect in-transit
traffic.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Capture CMSG metadata on client-side receive

kTLS sockets use CMSG to report decryption errors and the need
for session re-keying.

For RPC-with-TLS, an "application data" message contains a ULP
payload, and that is passed along to the RPC client. An "alert"
message triggers connection reset. Everything else is discarded.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Ignore data_ready callbacks during TLS handshakes

The RPC header parser doesn't recognize TLS handshake traffic, so it
will close the connection prematurely with an error. To avoid that,
shunt the transport's data_ready callback when there is a TLS
handshake in progress.

The XPRT_SOCK_IGNORE_RECV flag will be toggled by code added in a
subsequent patch.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: support abstract unix socket addresses

An "abtract" address for an AF_UNIX socket start with a nul and can
contain any bytes for the given length, but traditionally doesn't
contain other nuls. When reported, the leading nul is replaced by '@'.

sunrpc currently rejects connections to these addresses and reports them
as an empty string. To provide support for future use of these
addresses, allow them for outgoing connections and report them more
usefully.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

sunrpc: simplify one-level sysctl registration for xs_tunables_table

There is no need to declare an extra tables to just create directory,
this can be easily be done with a prefix path with register_sysctl().

Simplify this registration.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: fix shutdown of NFS TCP client socket

NFS server Duplicate Request Cache (DRC) algorithms rely on NFS clients
reconnecting using the same local TCP port. Unique NFS operations are
identified by the per-TCP connection set of XIDs. This prevents file
corruption when non-idempotent NFS operations are retried.

Currently, NFS client TCP connections are using different local TCP ports
when reconnecting to NFS servers.

After an NFS server initiates shutdown of the TCP connection, the NFS
client's TCP socket is set to NULL after the socket state has reached
TCP_LAST_ACK(9). When reconnecting, the new socket attempts to reuse
the same local port but fails with EADDRNOTAVAIL (99). This forces the
socket to use a different local TCP port to reconnect to the remote NFS
server.

State Transition and Events:
TCP_CLOSE_WAIT(8)
TCP_LAST_ACK(9)
connect(fail EADDRNOTAVAIL(99))
TCP_CLOSE(7)
bind on new port
connect success

dmesg excerpts showing reconnect switching from TCP local port of 926 to
763 after commit 7c81e6a9d75b:
[13354.947854] NFS call mkdir testW
...
[13405.654781] RPC: xs_tcp_state_change client 00000000037d0f03...
[13405.654813] RPC: state 8 conn 1 dead 0 zapped 1 sk_shutdown 1
[13405.654826] RPC: xs_data_ready...
[13405.654892] RPC: xs_tcp_state_change client 00000000037d0f03...
[13405.654895] RPC: state 9 conn 0 dead 0 zapped 1 sk_shutdown 3
[13405.654899] RPC: xs_tcp_state_change client 00000000037d0f03...
[13405.654900] RPC: state 9 conn 0 dead 0 zapped 1 sk_shutdown 3
[13405.654950] RPC: xs_connect scheduled xprt 00000000037d0f03
[13405.654975] RPC: xs_bind 0.0.0.0:926: ok (0)
[13405.654980] RPC: worker connecting xprt 00000000037d0f03 via tcp
to 10.101.6.228 (port 2049)
[13405.654991] RPC: 00000000037d0f03 connect status 99 connected 0
sock state 7
[13405.655001] RPC: xs_tcp_state_change client 00000000037d0f03...
[13405.655002] RPC: state 7 conn 0 dead 0 zapped 1 sk_shutdown 3
[13405.655024] RPC: xs_connect scheduled xprt 00000000037d0f03
[13405.655038] RPC: xs_bind 0.0.0.0:763: ok (0)
[13405.655041] RPC: worker connecting xprt 00000000037d0f03 via tcp
to 10.101.6.228 (port 2049)
[13405.655065] RPC: 00000000037d0f03 connect status 115 connected 0
sock state 2

State Transition and Events with patch applied:
TCP_CLOSE_WAIT(8)
TCP_LAST_ACK(9)
TCP_CLOSE(7)
connect(reuse of port succeeds)

dmesg excerpts showing reconnect on same TCP local port of 936 with patch
applied:
[ 257.139935] NFS: mkdir(0:59/560857152), testQ
[ 257.139937] NFS call mkdir testQ
...
[ 307.822702] RPC: state 8 conn 1 dead 0 zapped 1 sk_shutdown 1
[ 307.822714] RPC: xs_data_ready...
[ 307.822817] RPC: xs_tcp_state_change client 00000000ce702f14...
[ 307.822821] RPC: state 9 conn 0 dead 0 zapped 1 sk_shutdown 3
[ 307.822825] RPC: xs_tcp_state_change client 00000000ce702f14...
[ 307.822826] RPC: state 9 conn 0 dead 0 zapped 1 sk_shutdown 3
[ 307.823606] RPC: xs_tcp_state_change client 00000000ce702f14...
[ 307.823609] RPC: state 7 conn 0 dead 0 zapped 1 sk_shutdown 3
[ 307.823629] RPC: xs_tcp_state_change client 00000000ce702f14...
[ 307.823632] RPC: state 7 conn 0 dead 0 zapped 1 sk_shutdown 3
[ 307.823676] RPC: xs_connect scheduled xprt 00000000ce702f14
[ 307.823704] RPC: xs_bind 0.0.0.0:936: ok (0)
[ 307.823709] RPC: worker connecting xprt 00000000ce702f14 via tcp
to 10.101.1.30 (port 2049)
[ 307.823748] RPC: 00000000ce702f14 connect status 115 connected 0
sock state 2
...
[ 314.916193] RPC: state 7 conn 0 dead 0 zapped 1 sk_shutdown 3
[ 314.916251] RPC: xs_connect scheduled xprt 00000000ce702f14
[ 314.916282] RPC: xs_bind 0.0.0.0:936: ok (0)
[ 314.916292] RPC: worker connecting xprt 00000000ce702f14 via tcp
to 10.101.1.30 (port 2049)
[ 314.916342] RPC: 00000000ce702f14 connect status 115 connected 0
sock state 2

Fixes: 7c81e6a9d75b ("SUNRPC: Tweak TCP socket shutdown in the RPC client")
Signed-off-by: Siddharth Rajendra Kawar <sikawar@microsoft.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sock: Introduce trace_sk_data_ready()

As suggested by Cong, introduce a tracepoint for all ->sk_data_ready()
callback implementations. For example:

<...>
iperf-609 [002] ..... 70.660425: sk_data_ready: family=2 protocol=6 func=sock_def_readable
iperf-609 [002] ..... 70.660436: sk_data_ready: family=2 protocol=6 func=sock_def_readable
<...>

Suggested-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Treewide: Stop corrupting socket's task_frag

Since moving to memalloc_nofs_save/restore, SUNRPC has stopped setting the
GFP_NOIO flag on sk_allocation which the networking system uses to decide
when it is safe to use current->task_frag. The results of this are
unexpected corruption in task_frag when SUNRPC is involved in memory
reclaim.

The corruption can be seen in crashes, but the root cause is often
difficult to ascertain as a crashing machine's stack trace will have no
evidence of being near NFS or SUNRPC code. I believe this problem to
be much more pervasive than reports to the community may indicate.

Fix this by having kernel users of sockets that may corrupt task_frag due
to reclaim set sk_use_task_frag = false. Preemptively correcting this
situation for users that still set sk_allocation allows them to convert to
memalloc_nofs_save/restore without the same unexpected corruptions that are
sure to follow, unlikely to show up in testing, and difficult to bisect.

CC: Philipp Reisner <philipp.reisner@linbit.com>
CC: Lars Ellenberg <lars.ellenberg@linbit.com>
CC: "Christoph Böhmwalder" <christoph.boehmwalder@linbit.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Josef Bacik <josef@toxicpanda.com>
CC: Keith Busch <kbusch@kernel.org>
CC: Christoph Hellwig <hch@lst.de>
CC: Sagi Grimberg <sagi@grimberg.me>
CC: Lee Duncan <lduncan@suse.com>
CC: Chris Leech <cleech@redhat.com>
CC: Mike Christie <michael.christie@oracle.com>
CC: "James E.J. Bottomley" <jejb@linux.ibm.com>
CC: "Martin K. Petersen" <martin.petersen@oracle.com>
CC: Valentina Manea <valentina.manea.m@gmail.com>
CC: Shuah Khan <shuah@kernel.org>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: David Howells <dhowells@redhat.com>
CC: Marc Dionne <marc.dionne@auristor.com>
CC: Steve French <sfrench@samba.org>
CC: Christine Caulfield <ccaulfie@redhat.com>
CC: David Teigland <teigland@redhat.com>
CC: Mark Fasheh <mark@fasheh.com>
CC: Joel Becker <jlbec@evilplan.org>
CC: Joseph Qi <joseph.qi@linux.alibaba.com>
CC: Eric Van Hensbergen <ericvh@gmail.com>
CC: Latchesar Ionkov <lucho@ionkov.net>
CC: Dominique Martinet <asmadeus@codewreck.org>
CC: Ilya Dryomov <idryomov@gmail.com>
CC: Xiubo Li <xiubli@redhat.com>
CC: Chuck Lever <chuck.lever@oracle.com>
CC: Jeff Layton <jlayton@kernel.org>
CC: Trond Myklebust <trond.myklebust@hammerspace.com>
CC: Anna Schumaker <anna@kernel.org>
CC: Steffen Klassert <steffen.klassert@secunet.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>

Suggested-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

use less confusing names for iov_iter direction initializers

READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

treewide: use get_random_u32_below() instead of deprecated function

This is a simple mechanical transformation done by:

@@
expression E;
@@
- prandom_u32_max
+ get_random_u32_below
(E)

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Reviewed-by: SeongJae Park <sj@kernel.org> # for damon
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> # for arm
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

treewide: use prandom_u32_max() when possible, part 1

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}

@drop_var@
type T;
identifier VAR;
@@

{
- T VAR;
... when != VAR
}

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

SUNRPC: Fix races with rpc_killall_tasks()

Ensure that we immediately call rpc_exit_task() after waking up, and
that the tk_rpc_status cannot get clobbered by some other function.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: move from strlcpy with unused retval to strscpy

Follow the advice of the below link and prefer 'strscpy' in this
subsystem. Conversion is 1:1 because the return value is not used.
Generated by a coccinelle script.

Link: https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Don't reuse bvec on retransmission of the request

If a request is re-encoded and then retransmitted, we need to make sure
that we also re-encode the bvec, in case the page lists have changed.

Fixes: ff053dbbaffe ("SUNRPC: Move the call to xprt_send_pagedata() out of xprt_sock_sendmsg()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Replace dprintk() call site in xs_data_ready

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

net: remove noblock parameter from recvmsg() entities

The internal recvmsg() functions have two parameters 'flags' and 'noblock'
that were merged inside skb_recv_datagram(). As a follow up patch to commit
f4b41f062c42 ("net: remove noblock parameter from skb_recv_datagram()")
this patch removes the separate 'noblock' parameter for recvmsg().

Analogue to the referenced patch for skb_recv_datagram() the 'flags' and
'noblock' parameters are unnecessarily split up with e.g.

err = sk->sk_prot->recvmsg(sk, msg, size, flags & MSG_DONTWAIT,
flags & ~MSG_DONTWAIT, &addr_len);

or in

err = INDIRECT_CALL_2(sk->sk_prot->recvmsg, tcp_recvmsg, udp_recvmsg,
sk, msg, size, flags & MSG_DONTWAIT,
flags & ~MSG_DONTWAIT, &addr_len);

instead of simply using only flags all the time and check for MSG_DONTWAIT
where needed (to preserve for the formerly separated no(n)block condition).

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20220411124955.154876-1-socketcan@hartkopp.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Revert "SUNRPC: attempt AF_LOCAL connect on setup"

This reverts commit 7073ea8799a8cf73db60270986f14e4aae20fa80.

We must not try to connect the socket while the transport is under
construction, because the mechanisms to safely tear it down are not in
place. As the code stands, we end up leaking the sockets on a connection
error.

Reported-by: wanghai (M) <wanghai38@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Ensure timely close of disconnected AF_LOCAL sockets

When the rpcbind server closes the socket, we need to ensure that the
socket is closed by the kernel as soon as feasible, so add a
sk_state_change callback to trigger this close.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Don't leak sockets in xs_local_connect()

If there is still a closed socket associated with the transport, then we
need to trigger an autoclose before we can set up a new connection.

Reported-by: wanghai (M) <wanghai38@huawei.com>
Fixes: f00432063db1 ("SUNRPC: Ensure we flush any closed sockets before xs_xprt_free()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Move the call to xprt_send_pagedata() out of xprt_sock_sendmsg()

The client and server have different requirements for their memory
allocation, so move the allocation of the send buffer out of the socket
send code that is common to both.

Reported-by: NeilBrown <neilb@suse.de>
Fixes: b2648015d452 ("SUNRPC: Make the rpciod and xprtiod slab allocation modes consistent")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Ensure we flush any closed sockets before xs_xprt_free()

We must ensure that all sockets are closed before we call xprt_free()
and release the reference to the net namespace. The problem is that
calling fput() will defer closing the socket until delayed_fput() gets
called.
Let's fix the situation by allowing rpciod and the transport teardown
code (which runs on the system wq) to call __fput_sync(), and directly
close the socket.

Reported-by: Felix Fu <foyjog@gmail.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: a73881c96d73 ("SUNRPC: Fix an Oops in udp_poll()")
Cc: stable@vger.kernel.org # 5.1.x: 3be232f11a3c: SUNRPC: Prevent immediate close+reconnect
Cc: stable@vger.kernel.org # 5.1.x: 89f42494f92f: SUNRPC: Don't call connect() more than once on a TCP socket
Cc: stable@vger.kernel.org # 5.1.x
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: handle malloc failure in ->request_prepare

If ->request_prepare() detects an error, it sets ->rq_task->tk_status.
This is easy for callers to ignore.
The only caller is xprt_request_enqueue_receive() and it does ignore the
error, as does call_encode() which calls it. This can result in a
request being queued to receive a reply without an allocated receive buffer.

So instead of setting rq_task->tk_status, return an error, and store in
->tk_status only in call_encode();

The call to xprt_request_enqueue_receive() is now earlier in
call_encode(), where the error can still be handled.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Do not dereference non-socket transports in sysfs

Do not cast the struct xprt to a sock_xprt unless we know it is a UDP or
TCP transport. Otherwise the call to lock the mutex will scribble over
whatever structure is actually there. This has been seen to cause hard
system lockups when the underlying transport was RDMA.

Fixes: b49ea673e119 ("SUNRPC: lock against ->sock changing during sysfs read")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Make the rpciod and xprtiod slab allocation modes consistent

Make sure that rpciod and xprtiod are always using the same slab
allocation modes.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Improve accuracy of socket ENOBUFS determination

The current code checks for whether or not the socket is in a writeable
state after we get an EAGAIN. That is racy, since we've dropped the
socket lock, so the amount of free buffer may have changed.

Instead, let's check whether the socket is writeable before we try to
write to it. If that was the case, we do expect the message to be at
least partially sent unless we're in a low memory situation.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Replace internal use of SOCKWQ_ASYNC_NOSPACE

The socket's SOCKWQ_ASYNC_NOSPACE can be cleared by various actors in
the socket layer, so replace it with our own flag in the transport
sock_state field.

Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix socket waits for write buffer space

The socket layer requires that we use the socket lock to protect changes
to the sock->sk_write_pending field and others.

Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Only save the TCP source port after the connection is complete

Since the RPC client uses a non-blocking connect(), we do not expect to
see it return '0' under normal circumstances.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Don't call connect() more than once on a TCP socket

Avoid socket state races due to repeated calls to ->connect() using the
same socket. If connect() returns 0 due to the connection having
completed, but we are in fact in a closing state, then we may leave the
XPRT_CONNECTING flag set on the transport.

Reported-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>
Fixes: 3be232f11a3c ("SUNRPC: Prevent immediate close+reconnect")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: change locking for xs_swap_enable/disable

It is not in general safe to wait for XPRT_LOCKED to clear.
A wakeup is only sent when
- connection completes
- sock close completes
so during normal operations, this can wait indefinitely.

The event we need to protect against is ->inet being set to NULL, and
that happens under the recv_mutex lock.

So drop the handlign of XPRT_LOCKED and use recv_mutex instead.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC

rpc tasks can be marked as RPC_TASK_SWAPPER. This causes GFP_MEMALLOC
to be used for some allocations. This is needed in some cases, but not
in all where it is currently provided, and in some where it isn't
provided.

Currently *all* tasks associated with a rpc_client on which swap is
enabled get the flag and hence some GFP_MEMALLOC support.

GFP_MEMALLOC is provided for ->buf_alloc() but only swap-writes need it.
However xdr_alloc_bvec does not get GFP_MEMALLOC - though it often does
need it.

xdr_alloc_bvec is called while the XPRT_LOCK is held. If this blocks,
then it blocks all other queued tasks. So this allocation needs
GFP_MEMALLOC for *all* requests, not just writes, when the xprt is used
for any swap writes.

Similarly, if the transport is not connected, that will block all
requests including swap writes, so memory allocations should get
GFP_MEMALLOC if swap writes are possible.

So with this patch:
1/ we ONLY set RPC_TASK_SWAPPER for swap writes.
2/ __rpc_execute() sets PF_MEMALLOC while handling any task
with RPC_TASK_SWAPPER set, or when handling any task that
holds the XPRT_LOCKED lock on an xprt used for swap.
This removes the need for the RPC_IS_SWAPPER() test
in ->buf_alloc handlers.
3/ xprt_prepare_transmit() sets PF_MEMALLOC after locking
any task to a swapper xprt. __rpc_execute() will clear it.
3/ PF_MEMALLOC is set for all the connect workers.

Reviewed-by: Chuck Lever <chuck.lever@oracle.com> (for xprtrdma parts)
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: lock against ->sock changing during sysfs read

->sock can be set to NULL asynchronously unless ->recv_mutex is held.
So it is important to hold that mutex. Otherwise a sysfs read can
trigger an oops.
Commit 17f09d3f619a ("SUNRPC: Check if the xprt is connected before
handling sysfs reads") appears to attempt to fix this problem, but it
only narrows the race window.

Fixes: 17f09d3f619a ("SUNRPC: Check if the xprt is connected before handling sysfs reads")
Fixes: a8482488a7d6 ("SUNRPC query transport's source port")
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: clean up some inconsistent indenting

Eliminate the follow smatch warning:

net/sunrpc/xprtsock.c:1912 xs_local_connect() warn: inconsistent
indenting.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: use different lock keys for INET6 and LOCAL

xprtsock.c reclassifies sock locks based on the protocol.
However there are 3 protocols and only 2 classification keys.
The same key is used for both INET6 and LOCAL.

This causes lockdep complaints. The complaints started since Commit
ea9afca88bbe ("SUNRPC: Replace use of socket sk_callback_lock with
sock_lock") which resulted in the sock locks beings used more.

So add another key, and renumber them slightly.

Fixes: ea9afca88bbe ("SUNRPC: Replace use of socket sk_callback_lock with sock_lock")
Fixes: 176e21ee2ec8 ("SUNRPC: Support for RPC over AF_LOCAL transports")
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Prevent immediate close+reconnect

If we have already set up the socket and are waiting for it to connect,
then don't immediately close and retry.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix races when closing the socket

Ensure that we bump the xprt->connect_cookie when we set the
XPRT_CLOSE_WAIT flag so that another call to
xprt_conditional_disconnect() won't race with the reconnection.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Clean up xs_tcp_setup_sock()

Move the error handling into a single switch statement for clarity.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Replace use of socket sk_callback_lock with sock_lock

Since we do things like setting flags, etc it really is more appropriate
to use sock_lock().

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Tweak TCP socket shutdown in the RPC client

We only really need to call shutdown() if we're in the ESTABLISHED TCP
state, since that is the only case where the client is initiating a
close of an established connection.

If the socket is in FIN_WAIT1 or FIN_WAIT2, then we've already initiated
socket shutdown and are waiting for the server's reply, so do nothing.

In all other cases where we've already received a FIN from the server,
we should be able to just close the socket.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Simplify socket shutdown when not reusing TCP ports

If we're not required to reuse the TCP port, then we can just
immediately close the socket, and leave the cleanup details to the TCP
layer.

Fixes: e6237b6feb37 ("NFSv4.1: Don't rebind to the same source port when reconnecting to the server")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: Fix return value of get_srcport()

Since bc1c56e9bbe9 transport->srcport may by unset, causing
get_srcport() to return 0 when called. Fix this by querying the port
from the underlying socket instead of the transport.

Fixes: bc1c56e9bbe9 (SUNRPC: prevent port reuse on transports which don't request it)
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

params: lift param_set_uint_minmax to common code

It is a useful helper hence move it to common code so others can enjoy
it.

Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

SUNRPC query transport's source port

Provide ability to query transport's source port.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

sunrpc: keep track of the xprt_class in rpc_xprt structure

We need to keep track of the type for a given transport.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: prevent port reuse on transports which don't request it.

If an RPC client is created without RPC_CLNT_CREATE_REUSEPORT, it should
not reuse the source port when a TCP connection is re-established.
This is currently implemented by preventing the source port being
recorded after a successful connection (the call to xs_set_srcport()).

However the source port is also recorded after a successful bind in xs_bind().
This may not be needed at all and certainly is not wanted when
RPC_CLNT_CREATE_REUSEPORT wasn't requested.

So avoid that assignment when xprt.reuseport is not set.

With this change, NFSv4.1 and later mounts use a different port number on
each connection. This is helpful with some firewalls which don't cope
well with port reuse.

Signed-off-by: NeilBrown <neilb@suse.de>
Fixes: e6237b6feb37 ("NFSv4.1: Don't rebind to the same source port when reconnecting to the server")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix Oops in xs_tcp_send_request() when transport is disconnected

If a disconnection occurs while we're trying to reply to a server
callback, then we may end up calling xs_tcp_send_request() with a NULL
value for transport->inet, which trips up the call to
tcp_sock_set_cork().

Fixes: d737e5d41870 ("SUNRPC: Set TCP_CORK until the transmit queue is empty")
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Ensure the transport backchannel association

If the server sends CB_ calls on a connection that is not associated
with the backchannel, refuse to process the call and shut down the
connection. This avoids a NULL dereference crash in
xprt_complete_bc_request(). There's not much more we can do in this
situation unless we want to look into allowing all connections to be
associated with the fore and back channel.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Set TCP_CORK until the transmit queue is empty

When we have multiple RPC requests queued up, it makes sense to set the
TCP_CORK option while the transmit queue is non-empty.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple
warnings by explicitly adding multiple break statements instead of
letting the code fall through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net: sunrpc: xprtsock.c: Corrected few spellings ,in comments

Few trivial and rudimentary spell corrections.

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: correct error code comment in xs_tcp_setup_socket()

This comment was introduced by commit 6ea44adce915
("SUNRPC: ensure correct error is reported by xs_tcp_setup_socket()").

I believe EIO was a typo at the time: it should have been EAGAIN.

Subsequently, commit 0445f92c5d53 ("SUNRPC: Fix disconnection races")
changed that to ENOTCONN.

Rather than trying to keep the comment here in sync with the code in
xprt_force_disconnect(), make the point in a non-specific way.

Fixes: 6ea44adce915 ("SUNRPC: ensure correct error is reported by xs_tcp_setup_socket()")
Signed-off-by: Calum Mackay <calum.mackay@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: fix xs_read_xdr_buf for partial pages receive

When receiving pages data, return value 'ret' when positive includes
`buf->page_base`, so we should subtract that before it is used for
changing `offset` and comparing against `want`.

This was discovered on the very rare cases where the server returned a
chunk of bytes that when added to the already received amount of bytes
for the pages happened to match the current `recv.len`, for example
on this case:

buf->page_base : 258356
actually received from socket: 1740
ret : 260096
want : 260096

In this case neither of the two 'if ... goto out' trigger, and we
continue to tail parsing.

Worth to mention that the ensuing EMSGSIZE from the continued execution of
`xs_read_xdr_buf` may be observed by an application due to 4 superfluous
bytes being added to the pages data.

Fixes: 277e4ab7d530 ("SUNRPC: Simplify TCP receive code by switching to using iterators")
Signed-off-by: Dan Aloni <dan@kernelim.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: xprt_load_transport() needs to support the netid "rdma6"

According to RFC5666, the correct netid for an IPv6 addressed RDMA
transport is "rdma6", which we've supported as a mount option since
Linux-4.7. The problem is when we try to load the module "xprtrdma6",
that will fail, since there is no modulealias of that name.

Fixes: 181342c5ebe8 ("xprtrdma: Add rdma6 option to support NFS/RDMA IPv6")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Replace dprintk() call site in xs_nospace()

"no socket space" is an exceptional and infrequent condition
that troubleshooters want to know about.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

treewide: Remove uninitialized_var() usage

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
xargs perl -pi -e \
's/\buninitialized_var\(([^\)]+)\)/\1/g;
s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB
Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers
Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs
Signed-off-by: Kees Cook <keescook@chromium.org>

ipv6: add ip6_sock_set_addr_preferences

Add a helper to directly set the IPV6_ADD_PREFERENCES sockopt from kernel
space without going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: add tcp_sock_set_keepcnt

Add a helper to directly set the TCP_KEEPCNT sockopt from kernel space
without going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: add tcp_sock_set_keepintvl

Add a helper to directly set the TCP_KEEPINTVL sockopt from kernel space
without going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: add tcp_sock_set_keepidle

Add a helper to directly set the TCP_KEEP_IDLE sockopt from kernel
space without going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

tcp: add tcp_sock_set_user_timeout

Add a helper to directly set the TCP_USER_TIMEOUT sockopt from kernel
space without going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: add sock_set_reuseport

Add a helper to directly set the SO_REUSEPORT sockopt from kernel space
without going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: add sock_set_keepalive

Add a helper to directly set the SO_KEEPALIVE sockopt from kernel space
without going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

SUNRPC: Move xpt_mutex into socket xpo_sendto methods

It appears that the RPC/RDMA transport does not need serialization
of calls to its xpo_sendto method. Move the mutex into the socket
methods that still need that serialization.

Tail latencies are unambiguously better with this patch applied.
fio randrw 8KB 70/30 on NFSv3, smaller numbers are better:

clat percentiles (usec):

With xpt_mutex:
r | 99.99th=[ 8848]
w | 99.99th=[ 9634]

Without xpt_mutex:
r | 99.99th=[ 8586]
w | 99.99th=[ 8979]

Serializing the construction of RPC/RDMA transport headers is not
really necessary at this point, because the Linux NFS server
implementation never changes its credit grant on a connection. If
that should change, then svc_rdma_sendto will need to serialize
access to the transport's credit grant fields.

Reported-by: kbuild test robot <lkp@intel.com>
[ cel: fix uninitialized variable warning ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

SUNRPC: Fix backchannel RPC soft lockups

Currently, after the forward channel connection goes away,
backchannel operations are causing soft lockups on the server
because call_transmit_status's SOFTCONN logic ignores ENOTCONN.
Such backchannel Calls are aggressively retried until the client
reconnects.

Backchannel Calls should use RPC_TASK_NOCONNECT rather than
RPC_TASK_SOFTCONN. If there is no forward connection, the server is
not capable of establishing a connection back to the client, thus
that backchannel request should fail before the server attempts to
send it. Commit 58255a4e3ce5 ("NFSD: NFSv4 callback client should
use RPC_TASK_SOFTCONN") was merged several years before
RPC_TASK_NOCONNECT was available.

Because setup_callback_client() explicitly sets NOPING, the NFSv4.0
callback connection depends on the first callback RPC to initiate
a connection to the client. Thus NFSv4.0 needs to continue to use
RPC_TASK_SOFTCONN.

Suggested-by: Trond Myklebust <trondmy@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: <stable@vger.kernel.org> # v4.20+

SUNRPC: Teach server to use xprt_sock_sendmsg for socket sends

xprt_sock_sendmsg uses the more efficient iov_iter-enabled kernel
socket API, and is a pre-requisite for server send-side support for
TLS.

Note that svc_process no longer needs to reserve a word for the
stream record marker, since the TCP transport now provides the
record marker automatically in a separate buffer.

The dprintk() in svc_send_common is also removed. It didn't seem
crucial for field troubleshooting. If more is needed there, a trace
point could be added in xprt_sock_sendmsg().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

SUNRPC: Refactor xs_sendpages()

Re-locate xs_sendpages() so that it can be shared with server code.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

SUNRPC: remove redundant assignments to variable status

The variable status is being initialized with a value that is never
read and it is being updated later with a new value. The initialization
is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix backchannel latency metrics

I noticed that for callback requests, the reported backlog latency
is always zero, and the rtt value is crazy big. The problem was that
rqst->rq_xtime is never set for backchannel requests.

Fixes: 78215759e20d ("SUNRPC: Make RTT measurement more ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

NFSv4.1: Don't rebind to the same source port when reconnecting to the server

NFSv2, v3 and NFSv4 servers often have duplicate replay caches that look
at the source port when deciding whether or not an RPC call is a replay
of a previous call. This requires clients to perform strange TCP gymnastics
in order to ensure that when they reconnect to the server, they bind
to the same source port.

NFSv4.1 and NFSv4.2 have sessions that provide proper replay semantics,
that do not look at the source port of the connection. This patch therefore
ensures they can ignore the rebind requirement.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: fix race to sk_err after xs_error_report

Since commit 4f8943f80883 ("SUNRPC: Replace direct task wakeups from
softirq context") there has been a race to the value of the sk_err if both
XPRT_SOCK_WAKE_ERROR and XPRT_SOCK_WAKE_DISCONNECT are set. In that case,
we may end up losing the sk_err value that existed when xs_error_report was
called.

Fix this by reverting to the previous behavior: instead of using SO_ERROR
to retrieve the value at a later time (which might also return sk_err_soft),
copy the sk_err value onto struct sock_xprt, and use that value to wake
pending tasks.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Fixes: 4f8943f80883 ("SUNRPC: Replace direct task wakeups from softirq context")
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Don't receive TCP data into a request buffer that has been reset

If we've removed the request from the receive list, and have added
it back after resetting the request receive buffer, then we should
only receive message data if it is a new reply (i.e. if
transport->recv.copied is zero).

Fixes: 277e4ab7d530b ("SUNRPC: Simplify TCP receive code by switching...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Ensure the bvecs are reset when we re-encode the RPC request

The bvec tracks the list of pages, so if the number of pages changes
due to a re-encode, we need to reset the bvec as well.

Fixes: 277e4ab7d530 ("SUNRPC: Simplify TCP receive code by switching...")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.20+

SUNRPC: Fix up backchannel slot table accounting

Add a per-transport maximum limit in the socket case, and add
helpers to allow the NFSv4 code to discover that limit.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

xprtrdma: Modernize ops->connect

Adapt and apply changes that were made to the TCP socket connect
code. See the following commits for details on the purpose of
these changes:

Commit 7196dbb02ea0 ("SUNRPC: Allow changing of the TCP timeout parameters on the fly")
Commit 3851f1cdb2b8 ("SUNRPC: Limit the reconnect backoff timer to the max RPC message timeout")
Commit 02910177aede ("SUNRPC: Fix reconnection timeouts")

Some common transport code is moved to xprt.c to satisfy the code
duplication police.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Remove the bh-safe lock requirement on xprt->transport_lock

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Replace direct task wakeups from softirq context

Replace the direct task wakeups from inside a softirq context with
wakeups from a process context.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix up calculation of client message length

In the case where a record marker was used, xs_sendpages() needs
to return the length of the payload + record marker so that we
operate correctly in the case of a partial transmission.
When the callers check return value, they therefore need to
take into account the record marker length.

Fixes: 06b5fc3ad94e ("Merge tag 'nfs-rdma-for-5.1-1'...")
Cc: stable@vger.kernel.org # 5.1+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Add tracking of RPC level errors

Add variables to track RPC level errors so that we can distinguish
between issue that arose in the RPC transport layer as opposed to
those arising from the reply message.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Refactor xprt_request_wait_receive()

Convert the transport callback to actually put the request to sleep
instead of just setting a timeout. This is in preparation for
rpc_sleep_on_timeout().

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: fix uninitialized variable warning

Avoid following compiler warning on uninitialized variable

net/sunrpc/xprtsock.c: In function ‘xs_read_stream_request.constprop’:
net/sunrpc/xprtsock.c:525:10: warning: ‘read’ may be used uninitialized in this function [-Wmaybe-uninitialized]
return read;
^~~~
net/sunrpc/xprtsock.c:529:23: warning: ‘ret’ may be used uninitialized in this function [-Wmaybe-uninitialized]
return ret < 0 ? ret : read;
~~~~~~~~~~~~~~^~~~~~

Signed-off-by: Alakesh Haloi <alakesh.haloi@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix a client regression when handling oversized replies

If the server sends a reply that is larger than the pre-allocated
buffer, then the current code may fail to register how much of
the stream that it has finished reading. This again can lead to
hangs.

Fixes: e92053a52e68 ("SUNRPC: Handle zero length fragments correctly")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Convert remaining GFP_NOIO, and GFP_NOWAIT sites in sunrpc

Convert the remaining gfp_flags arguments in sunrpc to standard reclaiming
allocations, now that we set memalloc_nofs_save() as appropriate.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix an Oops in udp_poll()

udp_poll() checks the struct file for the O_NONBLOCK flag, so we must not
call it with a NULL file pointer.

Fixes: 0ffe86f48026 ("SUNRPC: Use poll() to fix up the socket requeue races")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Remove the redundant 'zerocopy' argument to xs_sendpages()

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Further cleanups of xs_sendpages()

Now that we send the pages using a struct msghdr, instead of
using sendpage(), we no longer need to 'prime the socket' with
an address for unconnected UDP messages.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Convert socket page send code to use iov_iter()

Simplify the page send code using iov_iter and bvecs.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Convert xs_send_kvec() to use iov_iter_kvec()

Prepare to the socket transmission code to use iov_iter.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Initiate a connection close on an ESHUTDOWN error in stream receive

If the client stream receive code receives an ESHUTDOWN error either
because the server closed the connection, or because it sent a
callback which cannot be processed, then we should shut down
the connection.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Don't suppress socket errors when a message read completes

If the message read completes, but the socket returned an error
condition, we should ensure to propagate that error.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Handle zero length fragments correctly

A zero length fragment is really a bug, but let's ensure we don't
go nuts when one turns up.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Don't reset the stream record info when the receive worker is running

To ensure that the receive worker has exclusive access to the stream record
info, we must not reset the contents other than when holding the
transport->recv_mutex.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Ensure rq_bytes_sent is reset before request transmission

When we resend a request, ensure that the 'rq_bytes_sent' is reset
to zero.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Use poll() to fix up the socket requeue races

Because we clear XPRT_SOCK_DATA_READY before reading, we can end up
with a situation where new data arrives, causing xs_data_ready() to
queue up a second receive worker job for the same socket, which then
immediately gets stuck waiting on the transport receive mutex.
The fix is to only clear XPRT_SOCK_DATA_READY once we're done reading,
and then to use poll() to check if we might need to queue up a new
job in order to deal with any new data.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Set memalloc_nofs_save() on all rpciod/xprtiod jobs

Set memalloc_nofs_save() on all the rpciod/xprtiod jobs so that we
ensure memory allocations for asynchronous rpc calls don't ever end
up recursing back to the NFS layer for memory reclaim.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Remove rpc_xprt::tsh_size

tsh_size was added to accommodate transports that send a pre-amble
before each RPC message. However, this assumes the pre-amble is
fixed in size, which isn't true for some transports. That makes
tsh_size not very generic.

Also I'd like to make the estimation of RPC send and receive
buffer sizes more precise. tsh_size doesn't currently appear to be
accounted for at all by call_allocate.

Therefore let's just remove the tsh_size concept, and make the only
transports that have a non-zero tsh_size employ a direct approach.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Fix TCP receive code on archs with flush_dcache_page()

After receiving data into the page cache, we need to call flush_dcache_page()
for the architectures that define it.

Fixes: 277e4ab7d530b ("SUNRPC: Simplify TCP receive code by switching...")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: stable@vger.kernel.org # v4.20
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Fix some kernel doc complaints

Clean up some warnings observed when building with "make W=1".

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: remove unused bc_up operation from rpc_xprt_ops

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: allow /proc entries without CONFIG_SUNRPC_DEBUG

If we want /proc/sys/sunrpc the current kernel also drags in other debug
features which we don't really want. Instead, we should always show the
following entries:

/proc/sys/sunrpc/udp_slot_table_entries
/proc/sys/sunrpc/tcp_slot_table_entries
/proc/sys/sunrpc/tcp_max_slot_table_entries
/proc/sys/sunrpc/min_resvport
/proc/sys/sunrpc/max_resvport
/proc/sys/sunrpc/tcp_fin_timeout

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Thomas Preston <thomas.preston@codethink.co.uk>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Fix a race with XPRT_CONNECTING

Ensure that we clear XPRT_CONNECTING before releasing the XPRT_LOCK so that
we don't have races between the (asynchronous) socket setup code and
tasks in xprt_connect().

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>

SUNRPC: Fix disconnection races

When the socket is closed, we need to call xprt_disconnect_done() in order
to clean up the XPRT_WRITE_SPACE flag, and wake up the sleeping tasks.

However, we also want to ensure that we don't wake them up before the socket
is closed, since that would cause thundering herd issues with everyone
piling up to retransmit before the TCP shutdown dance has completed.
Only the task that holds XPRT_LOCKED needs to wake up early in order to
allow the close to complete.

Reported-by: Dave Wysochanski <dwysocha@redhat.com>
Reported-by: Scott Mayhew <smayhew@redhat.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>

SUNRPC: Don't force a redundant disconnection in xs_read_stream()

If the connection is broken, then xs_tcp_state_change() will take care
of scheduling the socket close as soon as appropriate. xs_read_stream()
just needs to report the error.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix up socket polling

Ensure that we do not exit the socket read callback without clearing
XPRT_SOCK_DATA_READY.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Use the discard iterator rather than MSG_TRUNC

When discarding message data from the stream, we're better off using
the discard iterator, since that will work with non-TCP streams.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Treat EFAULT as a truncated message in xs_read_stream_request()

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix up handling of the XDRBUF_SPARSE_PAGES flag

If the allocator fails before it has reached the target number of pages,
then we need to recheck that we're not seeking past the page buffer.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Fix RPC receive hangs

The RPC code is occasionally hanging when the receive code fails to
empty the socket buffer due to a partial read of the data. When we
convert that to an EAGAIN, it appears we occasionally leave data in the
socket. The fix is to just keep reading until the socket returns
EAGAIN/EWOULDBLOCK.

Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Cristian Marussi <cristian.marussi@arm.com>
Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Cristian Marussi <cristian.marussi@arm.com>

missing bits of "iov_iter: Separate type from direction and use accessor functions"

sunrpc patches from nfs tree conflict with calling conventions change done
in iov_iter work. Trivial fixup...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

sunrpc: safely reallow resvport min/max inversion

Commits ffb6ca33b04b and e08ea3a96fc7 prevent setting xprt_min_resvport
greater than xprt_max_resvport, but may also break simple code that sets
one parameter then the other, if the new range does not overlap the old.

Also it looks racy to me, unless there's some serialization I'm not
seeing. Granted it would probably require malicious privileged processes
(unless there's a chance these might eventually be settable in unprivileged
containers), but still it seems better not to let userspace panic the
kernel.

Simpler seems to be to allow setting the parameters to whatever you want
but interpret xprt_min_resvport > xprt_max_resvport as the empty range.

Fixes: ffb6ca33b04b "sunrpc: Prevent resvport min/max inversion..."
Fixes: e08ea3a96fc7 "sunrpc: Prevent rexvport min/max inversion..."
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

sunrpc: Report connect_time in seconds

The way connection-oriented transports report connect_time is wrong:
it's supposed to be in seconds, not in jiffies.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: Fix connect metrics

For TCP, the logic in xprt_connect_status is currently never invoked
to record a successful connection. Commit 2a4919919a97 ("SUNRPC:
Return EAGAIN instead of ENOTCONN when waking up xprt->pending")
changed the way TCP xprt's are awoken after a connect succeeds.

Instead, change connection-oriented transports to bump connect_count
and compute connect_time the moment that XPRT_CONNECTED is set.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Clean up xs_udp_data_receive()

Simplify the retry logic.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Allow AF_LOCAL sockets to use the generic stream receive

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Clean up - rename xs_tcp_data_receive() to xs_stream_data_receive()

In preparation for sharing with AF_LOCAL.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Simplify TCP receive code by switching to using iterators

Most of this code should also be reusable with other socket types.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Cleanup: remove the unused 'task' argument from the request_send()

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Clean up transport write space handling

Treat socket write space handling in the same way we now treat transport
congestion: by denying the XPRT_LOCK until the transport signals that it
has free buffer space.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Turn off throttling of RPC slots for TCP sockets

The theory was that we would need to grab the socket lock anyway, so we
might as well use it to gate the allocation of RPC slots for a TCP
socket.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Support for congestion control when queuing is enabled

Both RDMA and UDP transports require the request to get a "congestion control"
credit before they can be transmitted. Right now, this is done when
the request locks the socket. We'd like it to happen when a request attempts
to be transmitted for the first time.
In order to support retransmission of requests that already hold such
credits, we also want to ensure that they get queued first, so that we
don't deadlock with requests that have yet to obtain a credit.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Treat the task and request as separate in the xprt_ops->send_request()

When we shift to using the transmit queue, then the task that holds the
write lock will not necessarily be the same as the one being transmitted.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Rename xprt->recv_lock to xprt->queue_lock

We will use the same lock to protect both the transmit and receive queues.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Simplify dealing with aborted partially transmitted messages

If the previous message was only partially transmitted, we need to close
the socket in order to avoid corruption of the message stream. To do so,
we currently hijack the unlocking of the socket in order to schedule
the close.
Now that we track the message offset in the socket state, we can move
that kind of checking out of the socket lock code, which is needed to
allow messages to remain queued after dropping the socket lock.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Add socket transmit queue offset tracking

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Move reset of TCP state variables into the reconnect code

Rather than resetting state variables in socket state_change() callback,
do it in the sunrpc TCP connect function itself.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

SUNRPC: Rename TCP receive-specific state variables

Since we will want to introduce similar TCP state variables for the
transmission of requests, let's rename the existing ones to label
that they are for the receive side.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

sunrpc: whitespace fixes

Remove trailing whitespace and blank line at EOF

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Add a ->free_slot transport callout

Refactor: xprtrdma needs to have better control over when RPCs are
awoken from the backlog queue, so replace xprt_free_slot with a
transport op callout.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Make RTT measurement more precise (Send)

Some RPC transports have more overhead in their send_request
callouts than others. For example, for RPC-over-RDMA:

- Marshaling an RPC often has to DMA map the RPC arguments

- Registration methods perform memory registration as part of
marshaling

To capture just server and network latencies more precisely: when
sending a Call, capture the rq_xtime timestamp _after_ the transport
header has been marshaled.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Move xprt_update_rtt callsite

Since commit 33849792cbcd ("xprtrdma: Detect unreachable NFS/RDMA
servers more reliably"), the xprtrdma transport now has a ->timer
callout. But xprtrdma does not need to compute RTT data, only UDP
needs that. Move the xprt_update_rtt call into the UDP transport
implementation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net: make getname() functions return length rather than use int* parameter

Changes since v1:
Added changes in these files:
drivers/infiniband/hw/usnic/usnic_transport.c
drivers/staging/lustre/lnet/lnet/lib-socket.c
drivers/target/iscsi/iscsi_target_login.c
drivers/vhost/net.c
fs/dlm/lowcomms.c
fs/ocfs2/cluster/tcp.c
security/tomoyo/network.c

Before:
All these functions either return a negative error indicator,
or store length of sockaddr into "int *socklen" parameter
and return zero on success.

"int *socklen" parameter is awkward. For example, if caller does not
care, it still needs to provide on-stack storage for the value
it does not need.

None of the many FOO_getname() functions of various protocols
ever used old value of *socklen. They always just overwrite it.

This change drops this parameter, and makes all these functions, on success,
return length of sockaddr. It's always >= 0 and can be differentiated
from an error.

Tests in callers are changed from "if (err)" to "if (err < 0)", where needed.

rpc_sockname() lost "int buflen" parameter, since its only use was
to be passed to kernel_getsockname() as &buflen and subsequently
not used in any way.

Userspace API is not changed.

text data bss dec hex filename
30108430 2633624 873672 33615726 200ef6e vmlinux.before.o
30108109 2633612 873672 33615393 200ee21 vmlinux.o

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: David S. Miller <davem@davemloft.net>
CC: linux-kernel@vger.kernel.org
CC: netdev@vger.kernel.org
CC: linux-bluetooth@vger.kernel.org
CC: linux-decnet-user@lists.sourceforge.net
CC: linux-wireless@vger.kernel.org
CC: linux-rdma@vger.kernel.org
CC: linux-sctp@vger.kernel.org
CC: linux-nfs@vger.kernel.org
CC: linux-x25@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

SUNRPC: Don't call __UDPX_INC_STATS() from a preemptible context

Calling __UDPX_INC_STATS() from a preemptible context leads to a
warning of the form:

BUG: using __this_cpu_add() in preemptible [00000000] code: kworker/u5:0/31
caller is xs_udp_data_receive_workfn+0x194/0x270
CPU: 1 PID: 31 Comm: kworker/u5:0 Not tainted 4.15.0-rc8-00076-g90ea9f1 #2
Workqueue: xprtiod xs_udp_data_receive_workfn
Call Trace:
dump_stack+0x85/0xc1
check_preemption_disabled+0xce/0xe0
xs_udp_data_receive_workfn+0x194/0x270
process_one_work+0x318/0x620
worker_thread+0x20a/0x390
? process_one_work+0x620/0x620
kthread+0x120/0x130
? __kthread_bind_mask+0x60/0x60
ret_from_fork+0x24/0x30

Since we're taking a spinlock in those functions anyway, let's fix the
issue by moving the call so that it occurs under the spinlock.

Reported-by: kernel test robot <fengguang.wu@intel.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Ensure we always close the socket after a connection shuts down

Ensure that we release the TCP socket once it is in the TCP_CLOSE or
TCP_TIME_WAIT state (and only then) so that we don't confuse rkhunter
and its ilk.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Add explicit rescheduling points in the receive path

When reading the reply from the server, insert an explicit
cond_resched() to avoid starving higher priority tasks.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Chunk reading of replies from the server

Read the TCP data in chunks of max 2MB so that we do not hog the
socket lock.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Handle ENETDOWN errors

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Allow connect to return EHOSTUNREACH

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net: sunrpc: mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

sunrpc: remove redundant initialization of sock

sock is being initialized and then being almost immediately updated
hence the initialized value is not being used and is redundant. Remove
the initialization. Cleans up clang warning:

warning: Value stored to 'sock' during its initialization is never read

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Add a separate spinlock to protect the RPC request receive list

This further reduces contention with the transport_lock, and allows us
to convert to using a non-bh-safe spinlock, since the list is now never
accessed from a bh context.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Cleanup xs_tcp_read_common()

Simplify the code to avoid a full copy of the struct xdr_skb_reader.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Don't loop forever in xs_tcp_data_receive()

Ensure that we don't hog the workqueue thread by requeuing the job
every 64 loops.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Don't hold the transport lock when receiving backchannel data

The backchannel request has no associated task, so it is going nowhere
until we call xprt_complete_bc_request().

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Don't hold the transport lock across socket copy operations

Instead add a mechanism to ensure that the request doesn't disappear
from underneath us while copying from the socket. We do this by
preventing xprt_release() from freeing the XDR buffers until the
flag RPC_TASK_MSG_RECV has been cleared from the request.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>

sunrpc: Const-ify all instances of struct rpc_xprt_ops

After transport instance creation, these function pointers never
change. Mark them as constant to prevent their use as an attack
vector for code injections.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprt_sock: fix regression in connection error reporting.

Commit 3d4762639dd3 ("tcp: remove poll() flakes when receiving
RST") in v4.12 changed the order in which ->sk_state_change()
and ->sk_error_report() are called when a socket is shut
down - sk_state_change() is now called first.

This causes xs_tcp_state_change() -> xs_sock_mark_closed() ->
xprt_disconnect_done() to wake all pending tasked with -EAGAIN.
When the ->sk_error_report() callback arrives, it is too late to
pass the error on, and it is lost.

As easy way to demonstrate the problem caused is to try to start
rpc.nfsd while rcpbind isn't running.
nfsd will attempt a tcp connection to rpcbind. A ECONNREFUSED
error is returned, but sunrpc code loses the error and keeps
retrying. If it saw the ECONNREFUSED, it would abort.

To fix this, handle the sk->sk_err in the TCP_CLOSE branch of
xs_tcp_state_change().

Fixes: 3d4762639dd3 ("tcp: remove poll() flakes when receiving RST")
Cc: stable@vger.kernel.org (v4.12)
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: ensure correct error is reported by xs_tcp_setup_socket()

If you attempt a TCP mount from an host that is unreachable in a way
that triggers an immediate error from kernel_connect(), that error
does not propagate up, instead EAGAIN is reported.

This results in call_connect_status receiving the wrong error.

A case that it easy to demonstrate is to attempt to mount from an
address that results in ENETUNREACH, but first deleting any default
route.
Without this patch, the mount.nfs process is persistently runnable
and is hard to kill. With this patch it exits as it should.

The problem is caused by the fact that xs_tcp_force_close() eventually
calls
xprt_wake_pending_tasks(xprt, -EAGAIN);
which causes an error return of -EAGAIN. so when xs_tcp_setup_sock()
calls
xprt_wake_pending_tasks(xprt, status);
the status is ignored.

Fixes: 4efdd92c9211 ("SUNRPC: Remove TCP client connection reset hack")
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

lib/vsprintf.c: remove %Z support

Now that %z is standartised in C99 there is no reason to support %Z.
Unlike %L it doesn't even make format strings smaller.

Use BUILD_BUG_ON in a couple ATM drivers.

In case anyone didn't notice lib/vsprintf.o is about half of SLUB which
is in my opinion is quite an achievement. Hopefully this patch inspires
someone else to trim vsprintf.c more.

Link: http://lkml.kernel.org/r/20170103230126.GA30170@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sunrpc: silence uninitialized variable warning

kstrtouint() can return a couple different error codes so the check for
"ret == -EINVAL" is wrong and static analysis tools correctly complain
that we can use "num" without initializing it. It's not super harmful
because we check the bounds. But it's also easy enough to fix.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: Allow xprt->ops->timer method to sleep

The transport lock is needed to protect the xprt_adjust_cwnd() call
in xs_udp_timer, but it is not necessary for accessing the
rq_reply_bytes_recvd or tk_status fields. It is correct to sublimate
the lock into UDP's xs_udp_timer method, where it is required.

The ->timer method has to take the transport lock if needed, but it
can now sleep safely, or even call back into the RPC scheduler.

This is more a clean-up than a fix, but the "issue" was introduced
by my transport switch patches back in 2005.

Fixes: 46c0ee8bc4ad ("RPC: separate xprt_timer implementations")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Allow changing of the TCP timeout parameters on the fly

When the NFSv4 server tells us the lease period, we usually want
to adjust down the timeout parameters on the TCP connection to
ensure that we don't miss lease renewals due to a faulty connection.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Refactor TCP socket timeout code into a helper function

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

udp: do fwd memory scheduling on dequeue

A new argument is added to __skb_recv_datagram to provide
an explicit skb destructor, invoked under the receive queue
lock.
The UDP protocol uses such argument to perform memory
reclaiming on dequeue, so that the UDP protocol does not
set anymore skb->desctructor.
Instead explicit memory reclaiming is performed at close() time and
when skbs are removed from the receive queue.
The in kernel UDP protocol users now need to call a
skb_recv_udp() variant instead of skb_recv_datagram() to
properly perform memory accounting on dequeue.

Overall, this allows acquiring only once the receive queue
lock on dequeue.

Tested using pktgen with random src port, 64 bytes packet,
wire-speed on a 10G link as sender and udp_sink as the receiver,
using an l4 tuple rxhash to stress the contention, and one or more
udp_sink instances with reuseport.

nr sinks vanilla patched
1 440 560
3 2150 2300
6 3650 3800
9 4450 4600
12 6250 6450

v1 -> v2:
- do rmem and allocated memory scheduling under the receive lock
- do bulk scheduling in first_packet_length() and in udp_destruct_sock()
- avoid the typdef for the dequeue callback

Suggested-by: Eric Dumazet <edumazet@google.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sunrpc: fix some missing rq_rbuffer assignments

We've been seeing some crashes in testing that look like this:

BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff8135ce99>] memcpy_orig+0x29/0x110
PGD 212ca2067 PUD 212ca3067 PMD 0
Oops: 0002 [#1] SMP
Modules linked in: rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache ppdev parport_pc i2c_piix4 sg parport i2c_core virtio_balloon pcspkr acpi_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c sd_mod ata_generic pata_acpi virtio_scsi 8139too ata_piix libata 8139cp mii virtio_pci floppy virtio_ring serio_raw virtio
CPU: 1 PID: 1540 Comm: nfsd Not tainted 4.9.0-rc1 #39
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2007
task: ffff88020d7ed200 task.stack: ffff880211838000
RIP: 0010:[<ffffffff8135ce99>] [<ffffffff8135ce99>] memcpy_orig+0x29/0x110
RSP: 0018:ffff88021183bdd0 EFLAGS: 00010206
RAX: 0000000000000000 RBX: ffff88020d7fa000 RCX: 000000f400000000
RDX: 0000000000000014 RSI: ffff880212927020 RDI: 0000000000000000
RBP: ffff88021183be30 R08: 01000000ef896996 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff880211704ca8
R13: ffff88021473f000 R14: 00000000ef896996 R15: ffff880211704800
FS: 0000000000000000(0000) GS:ffff88021fc80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000212ca1000 CR4: 00000000000006e0
Stack:
ffffffffa01ea087 ffffffff63400001 ffff880215145e00 ffff880211bacd00
ffff88021473f2b8 0000000000000004 00000000d0679d67 ffff880211bacd00
ffff88020d7fa000 ffff88021473f000 0000000000000000 ffff88020d7faa30
Call Trace:
[<ffffffffa01ea087>] ? svc_tcp_recvfrom+0x5a7/0x790 [sunrpc]
[<ffffffffa01f84d8>] svc_recv+0xad8/0xbd0 [sunrpc]
[<ffffffffa0262d5e>] nfsd+0xde/0x160 [nfsd]
[<ffffffffa0262c80>] ? nfsd_destroy+0x60/0x60 [nfsd]
[<ffffffff810a9418>] kthread+0xd8/0xf0
[<ffffffff816dbdbf>] ret_from_fork+0x1f/0x40
[<ffffffff810a9340>] ? kthread_park+0x60/0x60
Code: 00 00 48 89 f8 48 83 fa 20 72 7e 40 38 fe 7c 35 48 83 ea 20 48 83 ea 20 4c 8b 06 4c 8b 4e 08 4c 8b 56 10 4c 8b 5e 18 48 8d 76 20 <4c> 89 07 4c 89 4f 08 4c 89 57 10 4c 89 5f 18 48 8d 7f 20 73 d4
RIP [<ffffffff8135ce99>] memcpy_orig+0x29/0x110
RSP <ffff88021183bdd0>
CR2: 0000000000000000

Both Bruce and Eryu ran a bisect here and found that the problematic
patch was 68778945e46 (SUNRPC: Separate buffer pointers for RPC Call and
Reply messages).

That patch changed rpc_xdr_encode to use a new rq_rbuffer pointer to
set up the receive buffer, but didn't change all of the necessary
codepaths to set it properly. In particular the backchannel setup was
missing.

We need to set rq_rbuffer whenever rq_buffer is set. Ensure that it is.

Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Reported-by: Eryu Guan <guaneryu@gmail.com>
Tested-by: Eryu Guan <guaneryu@gmail.com>
Fixes: 68778945e46 "SUNRPC: Separate buffer pointers..."
Reported-by: J. Bruce Fields <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

udp: use it's own memory accounting schema

Completely avoid default sock memory accounting and replace it
with udp-specific accounting.

Since the new memory accounting model encapsulates completely
the required locking, remove the socket lock on both enqueue and
dequeue, and avoid using the backlog on enqueue.

Be sure to clean-up rx queue memory on socket destruction, using
udp its own sk_destruct.

Tested using pktgen with random src port, 64 bytes packet,
wire-speed on a 10G link as sender and udp_sink as the receiver,
using an l4 tuple rxhash to stress the contention, and one or more
udp_sink instances with reuseport.

nr readers Kpps (vanilla) Kpps (patched)
1 170 440
3 1250 2150
6 3000 3650
9 4200 4450
12 5700 6250

v4 -> v5:
- avoid unneeded test in first_packet_length

v3 -> v4:
- remove useless sk_rcvqueues_full() call

v2 -> v3:
- do not set the now unsed backlog_rcv callback

v1 -> v2:
- add memory pressure support
- fixed dropwatch accounting for ipv6

Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sunrpc: fix write space race causing stalls

Write space becoming available may race with putting the task to sleep
in xprt_wait_for_buffer_space(). The existing mechanism to avoid the
race does not work.

This (edited) partial trace illustrates the problem:

[1] rpc_task_run_action: task:43546@5 ... action=call_transmit
[2] xs_write_space <-xs_tcp_write_space
[3] xprt_write_space <-xs_write_space
[4] rpc_task_sleep: task:43546@5 ...
[5] xs_write_space <-xs_tcp_write_space

[1] Task 43546 runs but is out of write space.

[2] Space becomes available, xs_write_space() clears the
SOCKWQ_ASYNC_NOSPACE bit.

[3] xprt_write_space() attemts to wake xprt->snd_task (== 43546), but
this has not yet been queued and the wake up is lost.

[4] xs_nospace() is called which calls xprt_wait_for_buffer_space()
which queues task 43546.

[5] The call to sk->sk_write_space() at the end of xs_nospace() (which
is supposed to handle the above race) does not call
xprt_write_space() as the SOCKWQ_ASYNC_NOSPACE bit is clear and
thus the task is not woken.

Fix the race by resetting the SOCKWQ_ASYNC_NOSPACE bit in xs_nospace()
so the second call to sk->sk_write_space() calls xprt_write_space().

Suggested-by: Trond Myklebust <trondmy@primarydata.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
cc: stable@vger.kernel.org # 4.4
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Generalize the RPC buffer release API

xprtrdma needs to allocate the Call and Reply buffers separately.
TBH, the reliance on using a single buffer for the pair of XDR
buffers is transport implementation-specific.

Instead of passing just the rq_buffer into the buf_free method, pass
the task structure and let buf_free take care of freeing both
XDR buffers at once.

There's a micro-optimization here. In the common case, both
xprt_release and the transport's buf_free method were checking if
rq_buffer was NULL. Now the check is done only once per RPC.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Generalize the RPC buffer allocation API

xprtrdma needs to allocate the Call and Reply buffers separately.
TBH, the reliance on using a single buffer for the pair of XDR
buffers is transport implementation-specific.

Transports that want to allocate separate Call and Reply buffers
will ignore the "size" argument anyway. Don't bother passing it.

The buf_alloc method can't return two pointers. Instead, make the
method's return value an error code, and set the rq_buffer pointer
in the method itself.

This gives call_allocate an opportunity to terminate an RPC instead
of looping forever when a permanent problem occurs. If a request is
just bogus, or the transport is in a state where it can't allocate
resources for any request, there needs to be a way to kill the RPC
right there and not loop.

This immediately fixes a rare problem in the backchannel send path,
which loops if the server happens to send a CB request whose
call+reply size is larger than a page (which it shouldn't do yet).

One more issue: looks like xprt_inject_disconnect was incorrectly
placed in the failure path in call_allocate. It needs to be in the
success path, as it is for other call-sites.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: fix UDP memory accounting

The commit f9b2ee714c5c ("SUNRPC: Move UDP receive data path
into a workqueue context"), as a side effect, moved the
skb_free_datagram() call outside the scope of the related socket
lock, but UDP sockets require such lock to be held for proper
memory accounting.
Fix it by replacing skb_free_datagram() with
skb_free_datagram_locked().

Fixes: f9b2ee714c5c ("SUNRPC: Move UDP receive data path into a workqueue context")
Reported-and-tested-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Cc: stable@vger.kernel.org # 4.4+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Limit the reconnect backoff timer to the max RPC message timeout

...and ensure that we propagate it to new transports on the same
client.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Fix reconnection timeouts

When the connect attempt fails and backs off, we should start the clock
at the last connection attempt, not time at which we queue up the
reconnect job.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: disable the use of IPv6 temporary addresses.

If the net.ipv6.conf.*.use_temp_addr sysctl is set to '2',
then TCP connections over IPv6 will prefer a 'private' source
address.
These eventually expire and become invalid, typically after a week,
but the time is configurable.

When the local address becomes invalid the client will not be able to
receive replies from the server. Eventually the connection will timeout
or break and a new connection will be established, but this can take
half an hour (typically TCP connection break time).

RFC 4941, which describes private IPv6 addresses, acknowledges that some
applications might not work well with them and that the application may
explicitly a request non-temporary (i.e. "public") address.

I believe this is correct for SUNRPC clients. Without this change, a
client will occasionally experience a long delay if private addresses
have been enabled.

The privacy offered by private addresses is of little value for an NFS
server which requires client authentication.

For NFSv3 this will often not be a problem because idle connections are
closed after 5 minutes. For NFSv4 connections never go idle due to the
period RENEW (or equivalent) request.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Handle EADDRNOTAVAIL on connection failures

If the connect attempt immediately fails with an EADDRNOTAVAIL error, then
that means our choice of source port number was bad.
This error is expected when we set the SO_REUSEPORT socket option and we
have 2 sockets sharing the same source and destination address and port
combinations.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Fixes: 402e23b4ed9ed ("SUNRPC: Fix stupid typo in xs_sock_set_reuseport")
Cc: stable@vger.kernel.org # v4.0+

sunrpc: Prevent resvport min/max inversion via sysfs and module parameter

The current min/max resvport settings are independently limited
by the entire range of allowed ports, so max_resvport can be
set to a port lower than min_resvport.

Prevent inversion of min/max values when set through sysfs and
module parameter by setting the limits dependent on each other.

Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: Prevent resvport min/max inversion via sysctl

The current min/max resvport settings are independently limited
by the entire range of allowed ports, so max_resvport can be
set to a port lower than min_resvport.

Prevent inversion of min/max values when set through sysctl by
setting the limits dependent on each other.

Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: Fix reserved port range calculation

The range calculation for choosing the random reserved port will panic
with divide-by-zero when min_resvport == max_resvport, a range of one
port, not zero.

Fix the reserved port range calculation by adding one to the difference.

Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

rpc: share one xps between all backchannels

The spec allows backchannels for multiple clients to share the same tcp
connection. When that happens, we need to use the same xprt for all of
them. Similarly, we need the same xps.

This fixes list corruption introduced by the multipath code.

Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: Trond Myklebust <trondmy@primarydata.com>

SUNRPC: Fix suspicious enobufs issues.

The current test is racy when dealing with fast NICs.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: RPC transport queue must be low latency

rpciod can easily get congested due to the long list of queued rpc_tasks.
Having the receive queue wait in turn for those tasks to complete can
therefore be a bottleneck.

Address the problem by separating the workqueues into:
- rpciod: manages rpc_tasks
- xprtiod: manages transport related work.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Consolidate xs_tcp_data_ready and xs_data_ready

The only difference between the two at this point is the reset of
the connection timeout, and since everyone expect tcp ignore that value,
we can just throw it into the generic function.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Small optimisation of client receive

Do not queue the client receive work if we're still processing.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: Advertise maximum backchannel payload size

RPC-over-RDMA transports have a limit on how large a backward
direction (backchannel) RPC message can be. Ensure that the NFSv4.x
CREATE_SESSION operation advertises this limit to servers.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

sunrpc: set SOCK_FASYNC

sunrpc is using SOCKWQ_ASYNC_NOSPACE without setting SOCK_FASYNC,
so the recent optimizations done in sk_set_bit() and sk_clear_bit()
broke it.

There is still the risk that a subsequent sock_fasync() call
would clear SOCK_FASYNC, but sunrpc does not use this yet.

Fixes: 9317bb69824e ("net: SOCKWQ_ASYNC_NOSPACE optimizations")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Jiri Pirko <jiri@resnulli.us>
Reported-by: Huang, Ying <ying.huang@intel.com>
Tested-by: Jiri Pirko <jiri@resnulli.us>
Tested-by: Huang, Ying <ying.huang@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: udp: rename UDP_INC_STATS_BH()

Rename UDP_INC_STATS_BH() to __UDP_INC_STATS(),
and UDP6_INC_STATS_BH() to __UDP6_INC_STATS()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sock: tigthen lockdep checks for sock_owned_by_user

sock_owned_by_user should not be used without socket lock held. It seems
to be a common practice to check .owned before lock reclassification, so
provide a little help to abstract this check away.

Cc: linux-cifs@vger.kernel.org
Cc: linux-bluetooth@vger.kernel.org
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

sunrpc: do not pull udp headers on receive

Commit e6afc8ace6dd modified the udp receive path by pulling the udp
header before queuing an skbuff onto the receive queue.

Sunrpc also calls skb_recv_datagram to dequeue an skb from a udp
socket. Modify this receive path to also no longer expect udp
headers.

Fixes: e6afc8ace6dd ("udp: remove headers from UDP packets before queueing")

Reported-by: Franklin S Cooper Jr. <fcooper@ti.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Tested-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

SUNRPC: Use the multipath iterator to assign a transport to each task

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Fixup socket wait for memory

We're seeing hangs in the NFS client code, with loops of the form:

RPC: 30317 xmit incomplete (267368 left of 524448)
RPC: 30317 call_status (status -11)
RPC: 30317 call_transmit (status 0)
RPC: 30317 xprt_prepare_transmit
RPC: 30317 xprt_transmit(524448)
RPC: xs_tcp_send_request(267368) = -11
RPC: 30317 xmit incomplete (267368 left of 524448)
RPC: 30317 call_status (status -11)
RPC: 30317 call_transmit (status 0)
RPC: 30317 xprt_prepare_transmit
RPC: 30317 xprt_transmit(524448)

Turns out commit ceb5d58b2170 ("net: fix sock_wake_async() rcu protection")
moved SOCKWQ_ASYNC_NOSPACE out of sock->flags and into sk->sk_wq->flags,
however it never tried to fix up the code in net/sunrpc.

The new idiom is to use the flags in the RCU protected struct socket_wq.
While we're at it, clear out the now redundant places where we set/clear
SOCKWQ_ASYNC_NOSPACE and SOCK_NOSPACE. In principle, sk_stream_wait_memory()
is supposed to set these for us, so we only need to clear them in the
particular case of our ->write_space() callback.

Fixes: ceb5d58b2170 ("net: fix sock_wake_async() rcu protection")
Cc: Eric Dumazet <edumazet@google.com>
Cc: stable@vger.kernel.org # 4.4
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: drop unused xs_reclassify_socketX() helpers

xs_reclassify_socket4() and friends used to be called directly.
xs_reclassify_socket() is called instead nowadays.

The xs_reclassify_socketX() helper functions are empty when
CONFIG_DEBUG_LOCK_ALLOC is not defined. Drop them since they have no
callers.

Note that AF_LOCAL still calls xs_reclassify_socketu() directly but is
easily converted to generic xs_reclassify_socket().

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

net: rename SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA

This patch is a cleanup to make following patch easier to
review.

Goal is to move SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA
from (struct socket)->flags to a (struct socket_wq)->flags
to benefit from RCU protection in sock_wake_async()

To ease backports, we rename both constants.

Two new helpers, sk_set_bit(int nr, struct sock *sk)
and sk_clear_bit(int net, struct sock *sk) are added so that
following patch can change their implementation.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

SUNRPC: fix variable type

Due to incorrect len type bc_send_request returned always zero.

The problem has been detected using proposed semantic patch
scripts/coccinelle/tests/assign_signed_to_unsigned.cocci [1].

[1]: http://permalink.gmane.org/gmane.linux.kernel/2046107

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFS: Enable client side NFSv4.1 backchannel to use other transports

Forechannel transports get their own "bc_up" method to create an
endpoint for the backchannel service.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[Anna Schumaker: Add forward declaration of struct net to xprt.h]
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Abstract backchannel operations

xprt_{setup,destroy}_backchannel() won't be adequate for RPC/RMDA
bi-direction. In particular, receive buffers have to be pre-
registered and posted in order to receive incoming backchannel
requests.

Add a virtual function call to allow the insertion of appropriate
backchannel setup and destruction methods for each transport.

In addition, freeing a backchannel request is a little different
for RPC/RDMA. Introduce an rpc_xprt_op to handle the difference.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Tested-By: Devesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

SUNRPC: Use MSG_SENDPAGE_NOTLAST when calling sendpage()

If we're sending more pages via kernel_sendpage(), then set
MSG_SENDPAGE_NOTLAST.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: Use MSG_SENDPAGE_NOTLAST in xs_send_pagedata()

If we're sending more than one page via kernel_sendpage(), then set
MSG_SENDPAGE_NOTLAST between the pages so that we don't send suboptimal
frames (see commit 2f5338442425 and commit 35f9c09fe9c7).

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Move AF_LOCAL receive data path into a workqueue context

Now that we've done it for TCP and UDP, let's convert AF_LOCAL as well.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Move UDP receive data path into a workqueue context

Now that we've done it for TCP, let's convert UDP as well.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Move TCP receive data path into a workqueue context

Stream protocols such as TCP can often build up a backlog of data to be
read due to ordering. Combine this with the fact that some workloads such
as NFS read()-intensive workloads need to receive a lot of data per RPC
call, and it turns out that receiving the data from inside a softirq
context can cause starvation.

The following patch moves the TCP data receive into a workqueue context.
We still end up calling tcp_read_sock(), but we do so from a process
context, meaning that softirqs are enabled for most of the time.

With this patch, I see a doubling of read bandwidth when running a
multi-threaded iozone workload between a virtual client and server setup.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Refactor TCP receive

Move the TCP data receive loop out of xs_tcp_data_ready(). Doing so
will allow us to move the data receive out of the softirq context in
a set of followup patches.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: xs_sock_mark_closed() does not need to trigger socket autoclose

Under all conditions, it should be quite sufficient just to mark
the socket as disconnected. It will then be closed by the
transport shutdown or reconnect code.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Ensure that we wait for connections to complete before retrying

Commit 718ba5b87343, moved the responsibility for unlocking the socket to
xs_tcp_setup_socket, meaning that the socket will be unlocked before we
know that it has finished trying to connect. The following patch is based on
an initial patch by Russell King to ensure that we delay clearing the
XPRT_CONNECTING flag until we either know that we failed to initiate
a connection attempt, or the connection attempt itself failed.

Fixes: 718ba5b87343 ("SUNRPC: Add helpers to prevent socket create from racing")
Reported-by: Russell King <linux@arm.linux.org.uk>
Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Fix races between socket connection and destroy code

When we're destroying the socket transport, we need to ensure that
we cancel any existing delayed connection attempts, and order them
w.r.t. the call to xs_close().

Reported-by:"Suzuki K. Poulose" <suzuki.poulose@arm.com>
Acked-by: Jeff Layton <jlayton@poochiereds.net>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Prevent SYN+SYNACK+RST storms

Add a shutdown() call before we release the socket in order to ensure the
reset is sent before we try to reconnect.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: xs_reset_transport must mark the connection as disconnected

In case the reconnection attempt fails.

Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Allow sockets to do GFP_NOIO allocations

Follow up to commit c4a7ca774949 ("SUNRPC: Allow waiting on memory
allocation"). Allows the RPC socket code to do non-IO blocking.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Fix a thinko in xs_connect()

It is rather pointless to test the value of transport->inet after
calling xs_reset_transport(), since it will always be zero, and
so we will never see any exponential back off behaviour.
Also don't force early connections for SOFTCONN tasks. If the server
disconnects us, we should respect the exponential backoff.

Cc: stable@vger.kernel.org # 4.0+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Report TCP errors to the caller

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: translate -EAGAIN to -ENOBUFS when socket is writable.

The networking layer does not reliably report the distinction between
a non-block write failing because:
1/ the queue is too full already and
2/ a memory allocation attempt failed.

The distinction is important because in the first case it is
appropriate to retry as soon as the socket reports that it is
writable, and in the second case a small delay is required as the
socket will most likely report as writable but kmalloc could still
fail.

sk_stream_wait_memory() exhibits this distinction nicely, setting
'vm_wait' if a small wait is needed. However in the non-blocking case
it always returns -EAGAIN no matter the cause of the failure. This
-EAGAIN call get all the way to sunrpc.

The sunrpc layer expects EAGAIN to indicate the first cause, and
ENOBUFS to indicate the second. Various documentation suggests that
this is not unreasonable, but does not guarantee the desired error
codes.

The result of getting -EAGAIN when -ENOBUFS is expected is that the
send is tried again in a tight loop and soft lockups are reported.

so: add tests after calls to xs_sendpages() to translate -EAGAIN into
-ENOBUFS if the socket is writable. This cannot happen inside
xs_sendpages() as the test for "is socket writable" is different
between TCP and UDP.

With this change, the tight loop retrying xs_sendpages() becomes a
loop which only retries every 250ms, and so will not trigger a
soft-lockup warning.

It is possible that the write did fail because the queue was too full
and by the time xs_sendpages() completed, the queue was writable
again. In this case an extra 250ms delay is inserted that isn't
really needed. This circumstance suggests a degree of congestion so a
delay is not necessarily a bad thing, and it can only cause a single
250ms delay, not a series of them.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Don't confuse ENOBUFS with a write_space issue

ENOBUFS means that memory allocations are failing due to an actual
low memory situation. It should not be confused with being out of
socket buffer space.

Handle the problem by just punting to the delay in call_status.

Reported-by: Neil Brown <neilb@suse.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Set the TCP user timeout option on client sockets

Use the TCP_USER_TIMEOUT socket option to advertise to the server
how long we will keep the connection open if there is unacknowledged
data. See RFC5482.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Ensure we release the TCP socket once it has been closed

This fixes a regression introduced by commit caf4ccd4e88cf2 ("SUNRPC:
Make xs_tcp_close() do a socket shutdown rather than a sock_release").
Prior to that commit, the autoclose feature would ensure that an
idle connection would result in the socket being both disconnected and
released, whereas now only gets disconnected.

While the current behaviour is harmless, it does leave the port bound
until either RPC traffic resumes or the RPC client is shut down.

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Transport fault injection

It has been exceptionally useful to exercise the logic that handles
local immediate errors and RDMA connection loss. To enable
developers to test this regularly and repeatably, add logic to
simulate connection loss every so often.

Fault injection is disabled by default. It is enabled with

$ sudo echo xxx > /sys/kernel/debug/sunrpc/inject_fault/disconnect

where "xxx" is a large positive number of transport method calls
before a disconnect. A value of several thousand is usually a good
number that allows reasonable forward progress while still causing a
lot of connection drops.

These hooks are disabled when SUNRPC_DEBUG is turned off.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: turn swapper_enable/disable functions into rpc_xprt_ops

RDMA xprts don't have a sock_xprt, but an rdma_xprt, so the
xs_swapper_enable/disable functions will likely oops when fed an RDMA
xprt. Turn these functions into rpc_xprt_ops so that that doesn't
occur. For now the RDMA versions are no-ops that just return -EINVAL
on an attempt to swapon.

Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: lock xprt before trying to set memalloc on the sockets

It's possible that we could race with a call to xs_reset_transport, in
which case the xprt->inet pointer could be zeroed out while we're
accessing it. Lock the xprt before we try to set memalloc on it.

Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: if we're closing down a socket, clear memalloc on it first

We currently increment the memalloc_socks counter if we have a xprt that
is associated with a swapfile. That socket can be replaced however
during a reconnect event, and the memalloc_socks counter is never
decremented if that occurs.

When tearing down a xprt socket, check to see if the xprt is set up for
swapping and sk_clear_memalloc before releasing the socket if so.

Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: make xprt->swapper an atomic_t

Split xs_swapper into enable/disable functions and eliminate the
"enable" flag.

Currently, it's racy if you have multiple swapon/swapoff operations
running in parallel over the same xprt. Also fix it so that we only
set it to a memalloc socket on a 0->1 transition and only clear it
on a 1->0 transition.

Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: keep a count of swapfiles associated with the rpc_clnt

Jerome reported seeing a warning pop when working with a swapfile on
NFS. The nfs_swap_activate can end up calling sk_set_memalloc while
holding the rcu_read_lock and that function can sleep.

To fix that, we need to take a reference to the xprt while holding the
rcu_read_lock, set the socket up for swapping and then drop that
reference. But, xprt_put is not exported and having NFS deal with the
underlying xprt is a bit of layering violation anyway.

Fix this by adding a set of activate/deactivate functions that take a
rpc_clnt pointer instead of an rpc_xprt, and have nfs_swap_activate and
nfs_swap_deactivate call those.

Also, add a per-rpc_clnt atomic counter to keep track of the number of
active swapfiles associated with it. When the counter does a 0->1
transition, we enable swapping on the xprt, when we do a 1->0 transition
we disable swapping on it.

This also allows us to be a bit more selective with the RPC_TASK_SWAPPER
flag. If non-swapper and swapper clnts are sharing a xprt, then we only
need to flag the tasks from the swapper clnt with that flag.

Acked-by: Mel Gorman <mgorman@suse.de>
Reported-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: drop stale doc comments in xprtsock.c

Several functions have outdated arguments listed in the doc comments.
Drop documentation for arguments that no longer exist.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

kernel/params: constify struct kernel_param_ops uses

Most code already uses consts for the struct kernel_param_ops,
sweep the kernel for the last offending stragglers. Other than
include/linux/moduleparam.h and kernel/params.c all other changes
were generated with the following Coccinelle SmPL patch. Merge
conflicts between trees can be handled with Coccinelle.

In the future git could get Coccinelle merge support to deal with
patch --> fail --> grammar --> Coccinelle --> new patch conflicts
automatically for us on patches where the grammar is available and
the patch is of high confidence. Consider this a feature request.

Test compiled on x86_64 against:

* allnoconfig
* allmodconfig
* allyesconfig

@ const_found @
identifier ops;
@@

const struct kernel_param_ops ops = {
};

@ const_not_found depends on !const_found @
identifier ops;
@@

-struct kernel_param_ops ops = {
+const struct kernel_param_ops ops = {
};

Generated-by: Coccinelle SmPL
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Junio C Hamano <gitster@pobox.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: cocci@systeme.lip6.fr
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

SUNRPC: Cleanup to remove xs_tcp_close()

xs_tcp_close() is now just a call to xs_tcp_shutdown(), so remove it,
and replace the entry in xs_tcp_ops.

Suggested-by: Anna Schumaker <anna.schumaker@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Fix stupid typo in xs_sock_set_reuseport

Yes, kernel_setsockopt() hates you for using a char argument.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Define xs_tcp_fin_timeout only if CONFIG_SUNRPC_DEBUG

Now that the linger code is gone, the xs_tcp_fin_timeout variable has
no real function. Keep it for now, since it is part of the /proc
interface, but only define it if that /proc interface is enabled.

Suggested-by: Anna Schumaker <Anna.Schumaker@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Handle connection reset more efficiently.

If the connection reset is due to an active call on our side, then
the state change is sometimes not reported. Catch those instances
using xs_error_report() instead.
Also remove the xs_tcp_shutdown() call in xs_tcp_send_request() as
the change in behaviour makes it redundant.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Remove the redundant XPRT_CONNECTION_CLOSE flag

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Make xs_tcp_close() do a socket shutdown rather than a sock_release

Use of socket shutdown() means that we monitor the shutdown process
through the xs_tcp_state_change() callback, so it is preferable to
a full close in all cases unless we're destroying the transport.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Ensure xs_tcp_shutdown() requests a full close of the connection

The previous behaviour left the connection half-open in order to try
to scrape the last replies from the socket. Now that we have more reliable
reconnection, change the behaviour to close down the socket faster.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Cleanup to remove remaining uses of XPRT_CONNECTION_ABORT

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Remove TCP socket linger code

Now that we no longer use the partial shutdown code when closing the
socket, we no longer need to worry about the TCP linger2 state.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Remove TCP client connection reset hack

Instead we rely on SO_REUSEPORT to provide the reconnection semantics
that we need for NFSv2/v3.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: TCP/UDP always close the old socket before reconnecting

It is not safe to call xs_reset_transport() from inside xs_udp_setup_socket()
or xs_tcp_setup_socket(), since they do not own the correct locks. Instead,
do it in xs_connect().

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Add helpers to prevent socket create from racing

The socket lock is currently held by the task that is requesting the
connection be established. While that is efficient in the case where
the connection happens quickly, it is racy in the case where it doesn't.
What we really want is for the connect helper to be able to block access
to the socket while it is being set up.

This patch does so by arranging to transfer the socket lock from the
task that is requesting the connect attempt, and then releasing that
lock once everything is done.
This scheme also gives us automatic protection against collisions with
the RPC close code, so we can kill the cancel_delayed_work_sync()
call in xs_close().

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Ensure xs_reset_transport() resets the close connection flags

Otherwise, we may end up looping.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Do not clear the source port in xs_reset_transport

Now that we can reuse bound ports after a close, we never really want to
clear the transport's source port after it has been set. Doing so really
messes up the NFSv3 DRC on the server.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Handle EADDRINUSE on connect

Now that we're setting SO_REUSEPORT, we still need to handle the
case where a connect() is attempted, but the old socket is still
lingering.
Essentially, all we want to do here is handle the error by waiting
a few seconds and then retrying.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Set SO_REUSEPORT socket option for TCP connections

When using TCP, we need the ability to reuse port numbers after
a disconnection, so that the NFSv3 server knows that we're the same
client. Currently we use a hack to work around the TCP socket's
TIME_WAIT: we send an RST instead of closing, which doesn't
always work...
The SO_REUSEPORT option added in Linux 3.9 allows us to bind multiple
TCP connections to the same source address+port combination, and thus
to use ordinary TCP close() instead of the current hack.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: eliminate RPC_DEBUG

It's always set to whatever CONFIG_SUNRPC_DEBUG is, so just use that.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: add tracepoints in xs_tcp_data_recv

Add tracepoints inside the main loop on xs_tcp_data_recv that allow
us to keep an eye on what's happening during each phase of it.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: add new tracepoints in xprt handling code

...so we can keep track of when calls are sent and replies received.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFS/SUNRPC: Remove other deadlock-avoidance mechanisms in nfs_release_page()

Now that nfs_release_page() doesn't block indefinitely, other deadlock
avoidance mechanisms aren't needed.
- it doesn't hurt for kswapd to block occasionally. If it doesn't
want to block it would clear __GFP_WAIT. The current_is_kswapd()
was only added to avoid deadlocks and we have a new approach for
that.
- memory allocation in the SUNRPC layer can very rarely try to
->releasepage() a page it is trying to handle. The deadlock
is removed as nfs_release_page() doesn't block indefinitely.

So we don't need to set PF_FSTRANS for sunrpc network operations any
more.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

rpc: Add -EPERM processing for xs_udp_send_request()

If an iptables drop rule is added for an nfs server, the client can end up in
a softlockup. Because of the way that xs_sendpages() is structured, the -EPERM
is ignored since the prior bits of the packet may have been successfully queued
and thus xs_sendpages() returns a non-zero value. Then, xs_udp_send_request()
thinks that because some bits were queued it should return -EAGAIN. We then try
the request again and again, resulting in cpu spinning. Reproducer:

1) open a file on the nfs server '/nfs/foo' (mounted using udp)
2) iptables -A OUTPUT -d <nfs server ip> -j DROP
3) write to /nfs/foo
4) close /nfs/foo
5) iptables -D OUTPUT -d <nfs server ip> -j DROP

The softlockup occurs in step 4 above.

The previous patch, allows xs_sendpages() to return both a sent count and
any error values that may have occurred. Thus, if we get an -EPERM, return
that to the higher level code.

With this patch in place we can successfully abort the above sequence and
avoid the softlockup.

I also tried the above test case on an nfs mount on tcp and although the system
does not softlockup, I still ended up with the 'hung_task' firing after 120
seconds, due to the i/o being stuck. The tcp case appears a bit harder to fix,
since -EPERM appears to get ignored much lower down in the stack and does not
propogate up to xs_sendpages(). This case is not quite as insidious as the
softlockup and it is not addressed here.

Reported-by: Yigong Lou <ylou@akamai.com>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

rpc: return sent and err from xs_sendpages()

If an error is returned after the first bits of a packet have already been
successfully queued, xs_sendpages() will return a positive 'int' value
indicating success. Callers seem to treat this as -EAGAIN.

However, there are cases where its not a question of waiting for the write
queue to drain. For example, when there is an iptables rule dropping packets
to the destination, the lower level code can return -EPERM only after parts
of the packet have been successfully queued. In this case, we can end up
continuously retrying resulting in a kernel softlockup.

This patch is intended to make no changes in behavior but is in preparation for
subsequent patches that can make decisions based on both on the number of bytes
sent by xs_sendpages() and any errors that may have be returned.

Signed-off-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Don't wake tasks during connection abort

When aborting a connection to preserve source ports, don't wake the task in
xs_error_report. This allows tasks with RPC_TASK_SOFTCONN to succeed if the
connection needs to be re-established since it preserves the task's status
instead of setting it to the status of the aborting kernel_connect().

This may also avoid a potential conflict on the socket's lock.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Cc: stable@vger.kernel.org # 3.14+
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

rpc: xs_bind - do not bind when requesting a random ephemeral port

When attempting to establish a local ephemeral endpoint for a TCP or UDP
socket, do not explicitly call bind, instead let it happen implicilty when the
socket is first used.

The main motivating factor for this change is when TCP runs out of unique
ephemeral ports (i.e. cannot find any ephemeral ports which are not a part of
*any* TCP connection). In this situation if you explicitly call bind, then the
call will fail with EADDRINUSE. However, if you allow the allocation of an
ephemeral port to happen implicitly as part of connect (or other functions),
then ephemeral ports can be reused, so long as the combination of (local_ip,
local_port, remote_ip, remote_port) is unique for TCP sockets on the system.

This doesn't matter for UDP sockets, but it seemed easiest to treat TCP and UDP
sockets the same.

This can allow mount.nfs(8) to continue to function successfully, even in the
face of misbehaving applications which are creating a large number of TCP
connections.

Signed-off-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

replace strict_strto calls

Replace obsolete strict_strto calls with appropriate kstrto calls

Signed-off-by: Daniel Walter <dwalter@google.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Ensure that we handle ENOBUFS errors correctly.

Currently, an ENOBUFS error will result in a fatal error for the RPC
call. Normally, we will just want to wait and then retry.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: Remove sk_no_check setting

Setting sk_no_check to UDP_CSUM_NORCV seems to have no effect.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch: Mass conversion of smp_mb__*()

Mostly scripted conversion of the smp_mb__* barriers.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

net: Fix use after free by removing length arg from sk_data_ready callbacks.

Several spots in the kernel perform a sequence like:

skb_queue_tail(&sk->s_receive_queue, skb);
sk->sk_data_ready(sk, skb->len);

But at the moment we place the SKB onto the socket receive queue it
can be consumed and freed up. So this skb->len access is potentially
to freed up memory.

Furthermore, the skb->len can be modified by the consumer so it is
possible that the value isn't accurate.

And finally, no actual implementation of this callback actually uses
the length argument. And since nobody actually cared about it's
value, lots of call sites pass arbitrary values in such as '0' and
even '1'.

So just remove the length argument from the callback, that way there
is no confusion whatsoever and all of these use-after-free cases get
fixed as a side effect.

Based upon a patch by Eric Dumazet and his suggestion to audit this
issue tree-wide.

Signed-off-by: David S. Miller <davem@davemloft.net>

SUNRPC: Clear xpt_bc_xprt if xs_setup_bc_tcp failed

Don't move the assign of args->bc_xprt->xpt_bc_xprt out of xs_setup_bc_tcp,
because rpc_ping (which is in rpc_create) will using it.

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

NFSD/SUNRPC: Check rpc_xprt out of xs_setup_bc_tcp

Besides checking rpc_xprt out of xs_setup_bc_tcp,
increase it's reference (it's important).

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

NFSD: Free backchannel xprt in bc_destroy

Backchannel xprt isn't freed right now.
Free it in bc_destroy, and put the reference of THIS_MODULE.

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: fix memory leak of peer addresses in XPRT

Creating xprt failed after xs_format_peer_addresses,
sunrpc must free those memory of peer addresses in xprt.

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: RPC callbacks may be split across several TCP segments

Since TCP is a stream protocol, our callback read code needs to take into
account the fact that RPC callbacks are not always confined to a single
TCP segment.
This patch adds support for multiple TCP segments by ensuring that we
only remove the rpc_rqst structure from the 'free backchannel requests'
list once the data has been completely received. We rely on the fact
that TCP data is ordered for the duration of the connection.

Reported-by: shaobingqing <shaobingqing@bwstor.com.cn>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Fix races in xs_nospace()

When a send failure occurs due to the socket being out of buffer space,
we call xs_nospace() in order to have the RPC task wait until the
socket has drained enough to make it worth while trying again.
The current patch fixes a race in which the socket is drained before
we get round to setting up the machinery in xs_nospace(), and which
is reported to cause hangs.

Link: http://lkml.kernel.org/r/20140210170315.33dfc621@notabene.brown
Fixes: a9a6b52ee1ba (SUNRPC: Don't start the retransmission timer...)
Reported-by: Neil Brown <neilb@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

net: replace macros net_random and net_srandom with direct calls to prandom

This patch removes the net_random and net_srandom macros and replaces
them with direct calls to the prandom ones. As new commits only seem to
use prandom_u32 there is no use to keep them around.
This change makes it easier to grep for users of prandom_u32.

Signed-off-by: Aruna-Hewapathirane <aruna.hewapathirane@gmail.com>
Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

SUNRPC: Add tracepoint for socket errors

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

SUNRPC: Report connection error values to rpc_tasks on the pending queue

Currently we only report EAGAIN, which is not descriptive enough for
softconn tasks.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

sunrpc: fix some typos

Signed-off-by: Weng Meiling <wengmeiling.weng@huawei.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

sunrpc: comment typo fix

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: Fix a data corruption issue when retransmitting RPC calls

The following scenario can cause silent data corruption when doing
NFS writes. It has mainly been observed when doing database writes
using O_DIRECT.

1) The RPC client uses sendpage() to do zero-copy of the page data.
2) Due to networking issues, the reply from the server is delayed,
and so the RPC client times out.

3) The client issues a second sendpage of the page data as part of
an RPC call retransmission.

4) The reply to the first transmission arrives from the server
_before_ the client hardware has emptied the TCP socket send
buffer.
5) After processing the reply, the RPC state machine rules that
the call to be done, and triggers the completion callbacks.
6) The application notices the RPC call is done, and reuses the
pages to store something else (e.g. a new write).

7) The client NIC drains the TCP socket send buffer. Since the
page data has now changed, it reads a corrupted version of the
initial RPC call, and puts it on the wire.

This patch fixes the problem in the following manner:

The ordering guarantees of TCP ensure that when the server sends a
reply, then we know that the _first_ transmission has completed. Using
zero-copy in that situation is therefore safe.
If a time out occurs, we then send the retransmission using sendmsg()
(i.e. no zero-copy), We then know that the socket contains a full copy of
the data, and so it will retransmit a faithful reproduction even if the
RPC call completes, and the application reuses the O_DIRECT buffer in
the meantime.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org

SUNRPC: Cleanup xs_destroy()

There is no longer any need for a separate xs_local_destroy() helper.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: close a rare race in xs_tcp_setup_socket.

We have one report of a crash in xs_tcp_setup_socket.
The call path to the crash is:

xs_tcp_setup_socket -> inet_stream_connect -> lock_sock_nested.

The 'sock' passed to that last function is NULL.

The only way I can see this happening is a concurrent call to
xs_close:

xs_close -> xs_reset_transport -> sock_release -> inet_release

inet_release sets:
sock->sk = NULL;
inet_stream_connect calls
lock_sock(sock->sk);
which gets NULL.

All calls to xs_close are protected by XPRT_LOCKED as are most
activations of the workqueue which runs xs_tcp_setup_socket.
The exception is xs_tcp_schedule_linger_timeout.

So presumably the timeout queued by the later fires exactly when some
other code runs xs_close().

To protect against this we can move the cancel_delayed_work_sync()
call from xs_destory() to xs_close().

As xs_close is never called from the worker scheduled on
->connect_worker, this can never deadlock.

Signed-off-by: NeilBrown <neilb@suse.de>
[Trond: Make it safe to call cancel_delayed_work_sync() on AF_LOCAL sockets]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

sunrpc: comment typo fix

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Only update the TCP connect cookie on a successful connect

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Enable the keepalive option for TCP sockets

For NFSv4 we want to avoid retransmitting RPC calls unless the TCP
connection breaks. However we still want to detect TCP connection
breakage as soon as possible. Do this by setting the keepalive option
with the idle timeout and count set to the 'timeo' and 'retrans' mount
options.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Add tracepoints to help debug socket connection issues

Add client side debugging to help trace socket connection/disconnection
and unexpected state change issues.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net: add sk_stream_is_writeable() helper

Several call sites use the hardcoded following condition :

sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)

Lets use a helper because TCP_NOTSENT_LOWAT support will change this
condition for TCP sockets.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: Convert uses of typedef ctl_table to struct ctl_table

Reduce the uses of this unnecessary typedef.

Done via perl script:

$ git grep --name-only -w ctl_table net | \
xargs perl -p -i -e '\
sub trim { my ($local) = @_; $local =~ s/(^\s+|\s+$)//g; return $local; } \
s/\b(?<!struct\s)ctl_table\b(\s*\*\s*|\s+\w+)/"struct ctl_table " . trim($1)/ge'

Reflow the modified lines that now exceed 80 columns.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sunrpc: server back channel needs no rpcbind method

XPRT_BOUND is set on server backchannel xprts by xs_setup_bc_tcp()
(using xprt_set_bound()), and is never cleared, so ->rpcbind() will
never need to be called.

Reported-by: "Myklebust, Trond" <Trond.Myklebust@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: attempt AF_LOCAL connect on setup

In the gss-proxy case, setup time is when I know I'll have the right
namespace for the connect.

In other cases, it might be useful to get any connection errors
earlier--though actually in practice it doesn't make any difference for
rpcbind.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: Allow rpc_create() to request that TCP slots be unlimited

This is mainly for use by NFSv4.1, where the session negotiation
ultimately wants to decide how many RPC slots we can fill.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Report network/connection errors correctly for SOFTCONN rpc tasks

In the case of a SOFTCONN rpc task, we really want to ensure that it
reports errors like ENETUNREACH back to the caller. Currently, only
some of these errors are being reported back (connect errors are not),
and they are being converted by the RPC layer into EIO.

Reported-by: Jan Engelhardt <jengelh@inai.de>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

sunrpc: don't attempt to cancel unitialized work

As of dc107402ae06286a9ed33c32daf3f35514a7cb8d "SUNRPC: make AF_LOCAL connect synchronous", we no longer initialize connect_worker in the
AF_LOCAL case, resulting in warnings like:

WARNING: at lib/debugobjects.c:261 debug_print_object+0x8c/0xb0() Hardware name: Bochs
ODEBUG: assert_init not available (active state 0) object type: timer_list hint: stub_timer+0x0/0x20
Modules linked in: iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi nfsd auth_rpcgss nfs_acl lockd sunrpc
Pid: 4816, comm: nfsd Tainted: G W 3.8.0-rc2-00049-gdc10740 #801
Call Trace:
[<ffffffff8156ec00>] ? free_obj_work+0x60/0xa0
[<ffffffff81046aaf>] warn_slowpath_common+0x7f/0xc0
[<ffffffff81046ba6>] warn_slowpath_fmt+0x46/0x50
[<ffffffff8156eccc>] debug_print_object+0x8c/0xb0
[<ffffffff81055030>] ? timer_debug_hint+0x10/0x10
[<ffffffff8156f7e3>] debug_object_assert_init+0xe3/0x120
[<ffffffff81057ebb>] del_timer+0x2b/0x80
[<ffffffff8109c4e6>] ? mark_held_locks+0x86/0x110
[<ffffffff81065a29>] try_to_grab_pending+0xd9/0x150
[<ffffffff81065b57>] __cancel_work_timer+0x27/0xc0
[<ffffffff81065c03>] cancel_delayed_work_sync+0x13/0x20
[<ffffffffa0007067>] xs_destroy+0x27/0x80 [sunrpc]
[<ffffffffa00040d8>] xprt_destroy+0x78/0xa0 [sunrpc]
[<ffffffffa0006241>] xprt_put+0x21/0x30 [sunrpc]
[<ffffffffa00030cf>] rpc_free_client+0x10f/0x1a0 [sunrpc]
[<ffffffffa0002ff3>] ? rpc_free_client+0x33/0x1a0 [sunrpc]
[<ffffffffa0002f7e>] rpc_release_client+0x6e/0xb0 [sunrpc]
[<ffffffffa000325d>] rpc_shutdown_client+0xfd/0x1b0 [sunrpc]
[<ffffffffa0017196>] rpcb_put_local+0x106/0x130 [sunrpc]
...

Acked-by: "Myklebust, Trond" <Trond.Myklebust@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: make AF_LOCAL connect synchronous

It doesn't appear that anyone actually needs to connect asynchronously.

Also, using a workqueue for the connect means we lose the namespace
information from the original process. This is a problem since there's
no way to explicitly pass in a filesystem namespace for resolution of an
AF_LOCAL address.

Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

sunrpc: move address copy/cmp/convert routines and prototypes from clnt.h to addr.h

These routines are used by server and client code, so having them in a
separate header would be best.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: Pass pointers to struct rpc_xprt to the congestion window

Avoid access to task->tk_xprt

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Fix an RCU dereference in xs_local_rpcbind

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Pass a pointer to struct rpc_xprt to the connect callback

Avoid another RCU dereference by passing the pointer to struct rpc_xprt
from the caller.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Eliminate task->tk_xprt accesses that bypass rcu_dereference()

tk_xprt is just a shortcut for tk_client->cl_xprt, however cl_xprt is
defined as an __rcu variable. Replace dereferences of tk_xprt with
non-rcu dereferences where it is safe to do so.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: variable 'svsk' is unused in function bc_send_request

Silence a compile time warning.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Handle ECONNREFUSED in xs_local_setup_socket

Silence the unnecessary warning "unhandled error (111) connecting to..."
and convert it to a dprintk for debugging purposes.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: remove BUG_ON from bc_malloc

Replace BUG_ON() with WARN_ON_ONCE() and NULL return - the caller will handle
this like a memory allocation failure.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: remove BUG_ONs from *_reclassify_socket*

Replace multiple BUG_ON() calls with WARN_ON_ONCE() and early return when
sanity checking socket ownership (lock). The bind call will fail if the
socket was unsuccessfully reclassified.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Get rid of the xs_error_report socket callback

Chris Perl reports that we're seeing races between the wakeup call in
xs_error_report and the connect attempts. Basically, Chris has shown
that in certain circumstances, the call to xs_error_report causes the
rpc_task that is responsible for reconnecting to wake up early, thus
triggering a disconnect and retry.

Since the sk->sk_error_report() calls in the socket layer are always
followed by a tcp_done() in the cases where we care about waking up
the rpc_tasks, just let the state_change callbacks take responsibility
for those wake ups.

Reported-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Tested-by: Chris Perl <chris.perl@gmail.com>

SUNRPC: Prevent races in xs_abort_connection()

The call to xprt_disconnect_done() that is triggered by a successful
connection reset will trigger another automatic wakeup of all tasks
on the xprt->pending rpc_wait_queue. In particular it will cause an
early wake up of the task that called xprt_connect().

All we really want to do here is clear all the socket-specific state
flags, so we split that functionality out of xs_sock_mark_closed()
into a helper that can be called by xs_abort_connection()

Reported-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Tested-by: Chris Perl <chris.perl@gmail.com>

Revert "SUNRPC: Ensure we close the socket on EPIPE errors too..."

This reverts commit 55420c24a0d4d1fce70ca713f84aa00b6b74a70e.
Now that we clear the connected flag when entering TCP_CLOSE_WAIT,
the deadlock described in this commit is no longer possible.
Instead, the resulting call to xs_tcp_shutdown() can interfere
with pending reconnection attempts.

Reported-by: Chris Perl <chris.perl@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Tested-by: Chris Perl <chris.perl@gmail.com>

SUNRPC: Clear the connect flag when socket state is TCP_CLOSE_WAIT

This is needed to ensure that we call xprt_connect() upon the next
call to call_connect().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org
Tested-by: Chris Perl <chris.perl@gmail.com>

SUNRPC: Get rid of the redundant xprt->shutdown bit field

It is only set after everyone has dereferenced the transport,
and serves no useful purpose: setting it is racy, so all the
socket code, etc still needs to be able to cope with the cases
where they miss reading it.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Set alloc_slot for backchannel tcp ops

f39c1bfb5a03e2d255451bff05be0d7255298fa4 (SUNRPC: Fix a UDP transport
regression) introduced the "alloc_slot" function for xprt operations,
but never created one for the backchannel operations. This patch fixes
a null pointer dereference when mounting NFS over v4.1.

Call Trace:
[<ffffffffa0207957>] ? xprt_reserve+0x47/0x50 [sunrpc]
[<ffffffffa02023a4>] call_reserve+0x34/0x60 [sunrpc]
[<ffffffffa020e280>] __rpc_execute+0x90/0x400 [sunrpc]
[<ffffffffa020e61a>] rpc_async_schedule+0x2a/0x40 [sunrpc]
[<ffffffff81073589>] process_one_work+0x139/0x500
[<ffffffff81070e70>] ? alloc_worker+0x70/0x70
[<ffffffffa020e5f0>] ? __rpc_execute+0x400/0x400 [sunrpc]
[<ffffffff81073d1e>] worker_thread+0x15e/0x460
[<ffffffff8145c839>] ? preempt_schedule+0x49/0x70
[<ffffffff81073bc0>] ? rescuer_thread+0x230/0x230
[<ffffffff81079603>] kthread+0x93/0xa0
[<ffffffff81465d04>] kernel_thread_helper+0x4/0x10
[<ffffffff81079570>] ? kthread_freezable_should_stop+0x70/0x70
[<ffffffff81465d00>] ? gs_change+0x13/0x13

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

SUNRPC: Ensure that the TCP socket is closed when in CLOSE_WAIT

Instead of doing a shutdown() call, we need to do an actual close().
Ditto if/when the server is sending us junk RPC headers.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: Simon Kirby <sim@hostway.ca>
Cc: stable@vger.kernel.org

SUNRPC: Fix a UDP transport regression

Commit 43cedbf0e8dfb9c5610eb7985d5f21263e313802 (SUNRPC: Ensure that
we grab the XPRT_LOCK before calling xprt_alloc_slot) is causing
hangs in the case of NFS over UDP mounts.

Since neither the UDP or the RDMA transport mechanism use dynamic slot
allocation, we can skip grabbing the socket lock for those transports.
Add a new rpc_xprt_op to allow switching between the TCP and UDP/RDMA
case.

Note that the NFSv4.1 back channel assigns the slot directly
through rpc_run_bc_task, so we can ignore that case.

Reported-by: Dick Streefland <dick.streefland@altium.nl>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org [>= 3.1]

nfs: enable swap on NFS

Implement the new swapfile a_ops for NFS and hook up ->direct_IO. This
will set the NFS socket to SOCK_MEMALLOC and run socket reconnect under
PF_MEMALLOC as well as reset SOCK_MEMALLOC before engaging the protocol
->connect() method.

PF_MEMALLOC should allow the allocation of struct socket and related
objects and the early (re)setting of SOCK_MEMALLOC should allow us to
receive the packets required for the TCP connection buildup.

[jlayton@redhat.com: Restore PF_MEMALLOC task flags in all cases]
[dfeng@redhat.com: Fix handling of multiple swap files]
[a.p.zijlstra@chello.nl: Original patch]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nfs: skip commit in releasepage if we're freeing memory for fs-related reasons

We've had some reports of a deadlock where rpciod ends up with a stack
trace like this:

PID: 2507 TASK: ffff88103691ab40 CPU: 14 COMMAND: "rpciod/14"
#0 [ffff8810343bf2f0] schedule at ffffffff814dabd9
#1 [ffff8810343bf3b8] nfs_wait_bit_killable at ffffffffa038fc04 [nfs]
#2 [ffff8810343bf3c8] __wait_on_bit at ffffffff814dbc2f
#3 [ffff8810343bf418] out_of_line_wait_on_bit at ffffffff814dbcd8
#4 [ffff8810343bf488] nfs_commit_inode at ffffffffa039e0c1 [nfs]
#5 [ffff8810343bf4f8] nfs_release_page at ffffffffa038bef6 [nfs]
#6 [ffff8810343bf528] try_to_release_page at ffffffff8110c670
#7 [ffff8810343bf538] shrink_page_list.clone.0 at ffffffff81126271
#8 [ffff8810343bf668] shrink_inactive_list at ffffffff81126638
#9 [ffff8810343bf818] shrink_zone at ffffffff8112788f
#10 [ffff8810343bf8c8] do_try_to_free_pages at ffffffff81127b1e
#11 [ffff8810343bf958] try_to_free_pages at ffffffff8112812f
#12 [ffff8810343bfa08] __alloc_pages_nodemask at ffffffff8111fdad
#13 [ffff8810343bfb28] kmem_getpages at ffffffff81159942
#14 [ffff8810343bfb58] fallback_alloc at ffffffff8115a55a
#15 [ffff8810343bfbd8] ____cache_alloc_node at ffffffff8115a2d9
#16 [ffff8810343bfc38] kmem_cache_alloc at ffffffff8115b09b
#17 [ffff8810343bfc78] sk_prot_alloc at ffffffff81411808
#18 [ffff8810343bfcb8] sk_alloc at ffffffff8141197c
#19 [ffff8810343bfce8] inet_create at ffffffff81483ba6
#20 [ffff8810343bfd38] __sock_create at ffffffff8140b4a7
#21 [ffff8810343bfd98] xs_create_sock at ffffffffa01f649b [sunrpc]
#22 [ffff8810343bfdd8] xs_tcp_setup_socket at ffffffffa01f6965 [sunrpc]
#23 [ffff8810343bfe38] worker_thread at ffffffff810887d0
#24 [ffff8810343bfee8] kthread at ffffffff8108dd96
#25 [ffff8810343bff48] kernel_thread at ffffffff8100c1ca

rpciod is trying to allocate memory for a new socket to talk to the
server. The VM ends up calling ->releasepage to get more memory, and it
tries to do a blocking commit. That commit can't succeed however without
a connected socket, so we deadlock.

Fix this by setting PF_FSTRANS on the workqueue task prior to doing the
socket allocation, and having nfs_release_page check for that flag when
deciding whether to do a commit call. Also, set PF_FSTRANS
unconditionally in rpc_async_schedule since that function can also do
allocations sometimes.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@vger.kernel.org