svcrdma: Increase the per-transport rw_ctx count

rdma_rw_mr_factor() returns the smallest number of MRs needed to
move a particular number of pages. svcrdma currently asks for the
number of MRs needed to move RPCSVC_MAXPAGES (a little over one
megabyte), as that is the number of pages in the largest r/wsize
the server supports.

This call assumes that the client's NIC can bundle a full one
megabyte payload in a single rdma_segment. In fact, most NICs cannot
handle a full megabyte with a single rkey / rdma_segment. Clients
will typically split even a single Read chunk into many segments.

The server needs one MR to read each rdma_segment in a Read chunk,
and thus each one needs an rw_ctx.

svcrdma has been vastly underestimating the number of rw_ctxs needed
to handle 64 RPC requests with large Read chunks using small
rdma_segments.

Unfortunately there doesn't seem to be a good way to estimate this
number without knowing the client NIC's capabilities. Even then,
the client RPC/RDMA implementation is still free to split a chunk
into smaller segments (for example, it might be using physical
registration, which needs an rdma_segment per page).

The best we can do for now is choose a number that will guarantee
forward progress in the worst case (one page per segment).

At some later point, we could add some mechanisms to make this
much less of a problem:
- Add a core API to add more rw_ctxs to an already-established QP
- svcrdma could treat rw_ctx exhaustion as a temporary error and
try again
- Limit the number of Reads in flight

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

svcrdma: Update max_send_sges after QP is created

rdma_create_qp() can modify cap.max_send_sges. Copy the new value
to the svcrdma transport so it is bound by the new limit instead
of the requested one.

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

svcrdma: Report CQ depths in debugging output

Check that svc_rdma_accept() is allocating an appropriate number of
CQEs.

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

svcrdma: Reserve an extra WQE for ib_drain_rq()

Do as other ULPs already do: ensure there is an extra Receive WQE
reserved for the tear-down drain WR. I haven't heard reports of
problems but it can't hurt.

Note that rq_depth is used to compute the Send Queue depth as well,
so this fix should affect both the SQ and RQ.

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

svcrdma: Add back svcxprt_rdma::sc_read_complete_q

Having an nfsd thread waiting for an RDMA Read completion is
problematic if the Read responder (ie, the client) stops responding.
We need to go back to handling RDMA Reads by allowing the nfsd
thread to return to the svc scheduler, then waking a second thread
finish the RPC message once the Read completion fires.

As a next step, add a list_head upon which completed Reads are queued.
A subsequent patch will make use of this queue.

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

svcrdma: Clean up comment in svc_rdma_accept()

The comment that starts "Qualify ..." applies to only some of the
following code paragraph. Re-arrange the lines so the comment makes
more sense.

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

svcrdma: Remove queue-shortening warnings

These won't have much diagnostic value for site administrators.
Since they can't be disabled, they become noise.

What's more, the subsequent rdma_create_qp() call adjusts the Send
Queue size (possibly downward) without warning, making the size
reported by these pr_warns inaccurate.

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

svcrdma: Remove pointer addresses shown in dprintk()

There are a couple of dprintk() call sites in svc_rdma_accept()
that show pointer addresses. These days, displayed pointer addresses
are hashed and thus have little or no diagnostic value, especially
for site administrators.

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

svcrdma: Add lockdep class keys for transport locks

Two svcrdma-related transport locks can become quite contended.
Collate their use and make them easy to find in /proc/lock_stat for
better observability.

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

svcrdma: Add a utility workqueue to svcrdma

To handle work in the background, set up an UNBOUND workqueue for
svcrdma. Subsequent patches will make use of it.

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

svcrdma: Allocate new transports on device's NUMA node

The physical device's NUMA node ID is available when allocating an
svc_xprt for an incoming connection. Use that value to ensure the
svc_xprt structure is allocated on the NUMA node closest to the
device.

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

SUNRPC: always free ctxt when freeing deferred request

Since the ->xprt_ctxt pointer was added to svc_deferred_req, it has not
been sufficient to use kfree() to free a deferred request. We may need
to free the ctxt as well.

As freeing the ctxt is all that ->xpo_release_rqst() does, we repurpose
it to explicit do that even when the ctxt is not stored in an rqst.
So we now have ->xpo_release_ctxt() which is given an xprt and a ctxt,
which may have been taken either from an rqst or from a dreq. The
caller is now responsible for clearing that pointer after the call to
->xpo_release_ctxt.

We also clear dr->xprt_ctxt when the ctxt is moved into a new rqst when
revisiting a deferred request. This ensures there is only one pointer
to the ctxt, so the risk of double freeing in future is reduced. The
new code in svc_xprt_release which releases both the ctxt and any
rq_deferred depends on this.

Fixes: 773f91b2cf3f ("SUNRPC: Fix NFSD's request deferral on RDMA transports")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

SUNRPC: Remove ->xpo_secure_port()

There's no need for the cost of this extra virtual function call
during every RPC transaction: the RQ_SECURE bit can be set properly
in ->xpo_recvfrom() instead.

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

Revert "SUNRPC: Use RMW bitops in single-threaded hot paths"

The premise that "Once an svc thread is scheduled and executing an
RPC, no other processes will touch svc_rqst::rq_flags" is false.
svc_xprt_enqueue() examines the RQ_BUSY flag in scheduled nfsd
threads when determining which thread to wake up next.

Found via KCSAN.

Fixes: 28df0988815f ("SUNRPC: Use RMW bitops in single-threaded hot paths")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

SUNRPC: Use RMW bitops in single-threaded hot paths

I noticed CPU pipeline stalls while using perf.

Once an svc thread is scheduled and executing an RPC, no other
processes will touch svc_rqst::rq_flags. Thus bus-locked atomics are
not needed outside the svc thread scheduler.

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

svcrdma: xpt_bc_xprt is already clear in __svc_rdma_free()

svc_xprt_free() already "puts" the bc_xprt before calling the
transport's "free" method. No need to do it twice.

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

svcrdma: Convert rdma->sc_rw_ctxts to llist

Relieve contention on sc_rw_ctxt_lock by converting rdma->sc_rw_ctxts
to an llist.

The goal is to reduce the average overhead of Send completions,
because a transport's completion handlers are single-threaded on
one CPU core. This change reduces CPU utilization of each Send
completion by 2-3% on my server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-By: Tom Talpey <tom@talpey.com>

svcrdma: Relieve contention on sc_send_lock.

/proc/lock_stat indicates the the sc_send_lock is heavily
contended when the server is under load from a single client.

To address this, convert the send_ctxt free list to an llist.
Returning an item to the send_ctxt cache is now waitless, which
reduces the instruction path length in the single-threaded Send
handler (svc_rdma_wc_send).

The goal is to enable the ib_comp_wq worker to handle a higher
RPC/RDMA Send completion rate given the same CPU resources. This
change reduces CPU utilization of Send completion by 2-3% on my
server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-By: Tom Talpey <tom@talpey.com>

svcrdma: Remove sc_read_complete_q

Now that svc_rdma_recvfrom() waits for Read completion,
sc_read_complete_q is no longer used.

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

svcrdma: Add a "deferred close" helper

Refactor a bit of commonly used logic so that every site that wants
a close deferred to an nfsd thread does all the right things
(set_bit(XPT_CLOSE) then enqueue).

Also, once XPT_CLOSE is set on a transport, it is never cleared. If
XPT_CLOSE is already set, then the close is already being handled
and the enqueue can be skipped.

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

svcrdma: Maintain a Receive water mark

Post more Receives when the number of pending Receives drops below
a water mark. The batch mechanism is disabled if the underlying
device cannot support a reasonably-sized Receive Queue.

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

svcrdma: Provide an explanatory comment in CMA event handler

Clean up: explain why svc_xprt_enqueue() is invoked in the event
handler even though no xpt_flags bits are toggled here.

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

svcrdma: Hold private mutex while invoking rdma_accept()

RDMA core mutex locking was restructured by commit d114c6feedfe
("RDMA/cma: Add missing locking to rdma_accept()") [Aug 2020]. When
lock debugging is enabled, the RPC/RDMA server trips over the new
lockdep assertion in rdma_accept() because it doesn't call
rdma_accept() from its CM event handler.

As a temporary fix, have svc_rdma_accept() take the handler_mutex
explicitly. In the meantime, let's consider how to restructure the
RPC/RDMA transport to invoke rdma_accept() from the proper context.

Calls to svc_rdma_accept() are serialized with calls to
svc_rdma_free() by the generic RPC server layer.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/linux-rdma/20210209154014.GO4247@nvidia.com/
Fixes: d114c6feedfe ("RDMA/cma: Add missing locking to rdma_accept()")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

SUNRPC: Rename svc_encode_read_payload()

Clean up: "result payload" is a less confusing name for these
payloads. "READ payload" reflects only the NFS usage.

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

svcrdma: CM event handler clean up

Now that there's a core tracepoint that reports these events, there's
no need to maintain dprintk() call sites in each arm of the switch
statements.

We also refresh the documenting comments.

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

svcrdma: Remove transport reference counting

Jason tells me that a ULP cannot rely on getting an ESTABLISHED
and DISCONNECTED event pair for each connection, so transport
reference counting in the CM event handler will never be reliable.

Now that we have ib_drain_qp(), svcrdma should no longer need to
hold transport references while Sends and Receives are posted. So
remove the get/put call sites in the CM event handlers.

This eliminates a significant source of locked memory bus traffic.

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

svcrdma: Add common XDR decoders for RDMA and Read segments

Clean up: De-duplicate some code.

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

SUNRPC: Trace a few more generic svc_xprt events

In lieu of dprintks or tracepoints in each individual transport
implementation, introduce tracepoints in the generic part of the RPC
layer. These typically fire for connection lifetime events, so
shouldn't contribute a lot of noise.

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

svcrdma: Add tracepoints to report ->xpo_accept failures

Failure to accept a connection is typically due to a problem
specific to a transport type. Also, ->xpo_accept returns NULL
on error rather than reporting a specific problem.

So, add failure-specific tracepoints in svc_rdma_accept().

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

svcrdma: Displayed remote IP address should match stored address

Clean up: After commit 1e091c3bbf51 ("svcrdma: Ignore source port
when computing DRC hash"), the IP address stored in xpt_remote
always has a port number of zero. Thus, there's no need to display
the port number when displaying the IP address of a remote NFS/RDMA
client.

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

svcrdma: Fix leak of svc_rdma_recv_ctxt objects

Utilize the xpo_release_rqst transport method to ensure that each
rqstp's svc_rdma_recv_ctxt object is released even when the server
cannot return a Reply for that rqstp.

Without this fix, each RPC whose Reply cannot be sent leaks one
svc_rdma_recv_ctxt. This is a 2.5KB structure, a 4KB DMA-mapped
Receive buffer, and any pages that might be part of the Reply
message.

The leak is infrequent unless the network fabric is unreliable or
Kerberos is in use, as GSS sequence window overruns, which result
in connection loss, are more common on fast transports.

Fixes: 3a88092ee319 ("svcrdma: Preserve Receive buffer until svc_rdma_sendto")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

svcrdma: Remove svcrdma_cm_event() trace point

Clean up. This trace point is no longer needed because the RDMA/core
CMA code has an equivalent trace point that was added by commit
ed999f820a6c ("RDMA/cma: Add trace points in RDMA Connection
Manager").

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

nfsd: Fix NFSv4 READ on RDMA when using readv

svcrdma expects that the payload falls precisely into the xdr_buf
page vector. This does not seem to be the case for
nfsd4_encode_readv().

This code is called only when fops->splice_read is missing or when
RQ_SPLICE_OK is clear, so it's not a noticeable problem in many
common cases.

Add new transport method: ->xpo_read_payload so that when a READ
payload does not fit exactly in rq_res's page vector, the XDR
encoder can inform the RPC transport exactly where that payload is,
without the payload's XDR pad.

That way, when a Write chunk is present, the transport knows what
byte range in the Reply message is supposed to be matched with the
chunk.

Note that the Linux NFS server implementation of NFS/RDMA can
currently handle only one Write chunk per RPC-over-RDMA message.
This simplifies the implementation of this fix.

Fixes: b04209806384 ("nfsd4: allow exotic read compounds")
Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=198053
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

svcrdma: Use llist for managing cache of recv_ctxts

Use a wait-free mechanism for managing the svc_rdma_recv_ctxts free
list. Subsequently, sc_recv_lock can be eliminated.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove svc_rdma_wq

Clean up: the system workqueue will work just as well.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

rdma: Enable ib_alloc_cq to spread work over a device's comp_vectors

Send and Receive completion is handled on a single CPU selected at
the time each Completion Queue is allocated. Typically this is when
an initiator instantiates an RDMA transport, or when a target
accepts an RDMA connection.

Some ULPs cannot open a connection per CPU to spread completion
workload across available CPUs and MSI vectors. For such ULPs,
provide an API that allows the RDMA core to select a completion
vector based on the device's complement of available comp_vecs.

ULPs that invoke ib_alloc_cq() with only comp_vector 0 are converted
to use the new API so that their completion workloads interfere less
with each other.

Suggested-by: Håkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Cc: <linux-cifs@vger.kernel.org>
Cc: <v9fs-developer@lists.sourceforge.net>
Link: https://lore.kernel.org/r/20190729171923.13428.52555.stgit@manet.1015granger.net
Signed-off-by: Doug Ledford <dledford@redhat.com>

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

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

svcrdma: Ignore source port when computing DRC hash

The DRC appears to be effectively empty after an RPC/RDMA transport
reconnect. The problem is that each connection uses a different
source port, which defeats the DRC hash.

Clients always have to disconnect before they send retransmissions
to reset the connection's credit accounting, thus every retransmit
on NFS/RDMA will miss the DRC.

An NFS/RDMA client's IP source port is meaningless for RDMA
transports. The transport layer typically sets the source port value
on the connection to a random ephemeral port. The server already
ignores it for the "secure port" check. See commit 16e4d93f6de7
("NFSD: Ignore client's source port on RDMA transports").

The Linux NFS server's DRC resolves XID collisions from the same
source IP address by using the checksum of the first 200 bytes of
the RPC call header.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove syslog warnings in work completion handlers

These can result in a lot of log noise, and are able to be triggered
by client misbehavior. Since there are trace points in these
handlers now, there's no need to spam the log.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Squelch compiler warning when SUNRPC_DEBUG is disabled

CC [M] net/sunrpc/xprtrdma/svc_rdma_transport.o
linux/net/sunrpc/xprtrdma/svc_rdma_transport.c: In function ‘svc_rdma_accept’:
linux/net/sunrpc/xprtrdma/svc_rdma_transport.c:452:19: warning: variable ‘sap’ set but not used [-Wunused-but-set-variable]
struct sockaddr *sap;
^

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove max_sge check at connect time

Two and a half years ago, the client was changed to use gathered
Send for larger inline messages, in commit 655fec6987b ("xprtrdma:
Use gathered Send for large inline messages"). Several fixes were
required because there are a few in-kernel device drivers whose
max_sge is 3, and these were broken by the change.

Apparently my memory is going, because some time later, I submitted
commit 25fd86eca11c ("svcrdma: Don't overrun the SGE array in
svc_rdma_send_ctxt"), and after that, commit f3c1fd0ee294 ("svcrdma:
Reduce max_send_sges"). These too incorrectly assumed in-kernel
device drivers would have more than a few Send SGEs available.

The fix for the server side is not the same. This is because the
fundamental problem on the server is that, whether or not the client
has provisioned a chunk for the RPC reply, the server must squeeze
even the most complex RPC replies into a single RDMA Send. Failing
in the send path because of Send SGE exhaustion should never be an
option.

Therefore, instead of failing when the send path runs out of SGEs,
switch to using a bounce buffer mechanism to handle RPC replies that
are too complex for the device to send directly. That allows us to
remove the max_sge check to enable drivers with small max_sge to
work again.

Reported-by: Don Dutile <ddutile@redhat.com>
Fixes: 25fd86eca11c ("svcrdma: Don't overrun the SGE array in ...")
Cc: stable@vger.kernel.org
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

sunrpc: remove unused xpo_prep_reply_hdr callback

xpo_prep_reply_hdr are not used now.

It was defined for tcp transport only, however it cannot be
called indirectly, so let's move it to its caller and
remove unused callback.

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

sunrpc: remove svc_rdma_bc_class

Remove svc_xprt_class svc_rdma_bc_class and related functions.

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

sunrpc: replace svc_serv->sv_bc_xprt by boolean flag

svc_serv-> sv_bc_xprt is netns-unsafe and cannot be used as pointer.
To prevent its misuse in future it is replaced by new boolean flag.

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

svcrdma: Reduce max_send_sges

There's no need to request a large number of send SGEs because the
inline threshold already constrains the number of SGEs per Send.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

rpc: remove unneeded variable 'ret' in rdma_listen_handler

The ret is not modified after initalization, So just remove the variable
and return 0.

Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

IB/core: add max_send_sge and max_recv_sge attributes

This patch replaces the ib_device_attr.max_sge with max_send_sge and
max_recv_sge. It allows ulps to take advantage of devices that have very
different send and recv sge depths. For example cxgb4 has a max_recv_sge
of 4, yet a max_send_sge of 16. Splitting out these attributes allows
much more efficient use of the SQ for cxgb4 with ulps that use the RDMA_RW
API. Consider a large RDMA WRITE that has 16 scattergather entries.
With max_sge of 4, the ulp would send 4 WRITE WRs, but with max_sge of
16, it can be done with 1 WRITE WR.

Acked-by: Sagi Grimberg <sagi@grimberg.me>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Selvin Xavier <selvin.xavier@broadcom.com>
Acked-by: Shiraz Saleem <shiraz.saleem@intel.com>
Acked-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

svcrdma: Don't overrun the SGE array in svc_rdma_send_ctxt

Receive buffers are always the same size, but each Send WR has a
variable number of SGEs, based on the contents of the xdr_buf being
sent.

While assembling a Send WR, keep track of the number of SGEs so that
we don't exceed the device's maximum, or walk off the end of the
Send SGE array.

For now the Send path just fails if it exceeds the maximum.

The current logic in svc_rdma_accept bases the maximum number of
Send SGEs on the largest NFS request that can be sent or received.
In the transport layer, the limit is actually based on the
capabilities of the underlying device, not on properties of the
Upper Layer Protocol.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Introduce svc_rdma_send_ctxt

svc_rdma_op_ctxt's are pre-allocated and maintained on a per-xprt
free list. This eliminates the overhead of calling kmalloc / kfree,
both of which grab a globally shared lock that disables interrupts.
Introduce a replacement to svc_rdma_op_ctxt's that is built
especially for the svcrdma Send path.

Subsequent patches will take advantage of this new structure by
allocating real resources which are then cached in these objects.
The allocations are freed when the transport is torn down.

I've renamed the structure so that static type checking can be used
to ensure that uses of op_ctxt and send_ctxt are not confused. As an
additional clean up, structure fields are renamed to conform with
kernel coding conventions.

Additional clean ups:
- Handle svc_rdma_send_ctxt_get allocation failure at each call
site, rather than pre-allocating and hoping we guessed correctly
- All send_ctxt_put call-sites request page freeing, so remove
the @free_pages argument
- All send_ctxt_put call-sites unmap SGEs, so fold that into
svc_rdma_send_ctxt_put

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Persistently allocate and DMA-map Receive buffers

The current Receive path uses an array of pages which are allocated
and DMA mapped when each Receive WR is posted, and then handed off
to the upper layer in rqstp::rq_arg. The page flip releases unused
pages in the rq_pages pagelist. This mechanism introduces a
significant amount of overhead.

So instead, kmalloc the Receive buffer, and leave it DMA-mapped
while the transport remains connected. This confers a number of
benefits:

* Each Receive WR requires only one receive SGE, no matter how large
the inline threshold is. This helps the server-side NFS/RDMA
transport operate on less capable RDMA devices.

* The Receive buffer is left allocated and mapped all the time. This
relieves svc_rdma_post_recv from the overhead of allocating and
DMA-mapping a fresh buffer.

* svc_rdma_wc_receive no longer has to DMA unmap the Receive buffer.
It has to DMA sync only the number of bytes that were received.

* svc_rdma_build_arg_xdr no longer has to free a page in rq_pages
for each page in the Receive buffer, making it a constant-time
function.

* The Receive buffer is now plugged directly into the rq_arg's
head[0].iov_vec, and can be larger than a page without spilling
over into rq_arg's page list. This enables simplification of
the RDMA Read path in subsequent patches.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove sc_rq_depth

Clean up: No need to retain rq_depth in struct svcrdma_xprt, it is
used only in svc_rdma_accept().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Introduce svc_rdma_recv_ctxt

svc_rdma_op_ctxt's are pre-allocated and maintained on a per-xprt
free list. This eliminates the overhead of calling kmalloc / kfree,
both of which grab a globally shared lock that disables interrupts.
To reduce contention further, separate the use of these objects in
the Receive and Send paths in svcrdma.

Subsequent patches will take advantage of this separation by
allocating real resources which are then cached in these objects.
The allocations are freed when the transport is torn down.

I've renamed the structure so that static type checking can be used
to ensure that uses of op_ctxt and recv_ctxt are not confused. As an
additional clean up, structure fields are renamed to conform with
kernel coding conventions.

As a final clean up, helpers related to recv_ctxt are moved closer
to the functions that use them.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Trace key RDMA API events

This includes:
* Posting on the Send and Receive queues
* Send, Receive, Read, and Write completion
* Connect upcalls
* QP errors

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Trace key RPC/RDMA protocol events

This includes:
* Transport accept and tear-down
* Decisions about using Write and Reply chunks
* Each RDMA segment that is handled
* Whenever an RDMA_ERR is sent

As a clean-up, I've standardized the order of the includes, and
removed some now redundant dprintk call sites.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Use passed-in net namespace when creating RDMA listener

Ensure each RDMA listener and its children transports are created in
the same net namespace as the user that started the NFS service.
This is similar to how listener sockets are created in
svc_create_socket, required for enabling support for containers.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Add proper SPDX tags for NetApp-contributed source

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

sunrpc: Save remote presentation address in svc_xprt for trace events

TP_printk defines a format string that is passed to user space for
converting raw trace event records to something human-readable.

My user space's printf (Oracle Linux 7), however, does not have a
%pI format specifier. The result is that what is supposed to be an
IP address in the output of "trace-cmd report" is just a string that
says the field couldn't be displayed.

To fix this, adopt the same approach as the client: maintain a pre-
formated presentation address for occasions when %pI is not
available.

The location of the trace_svc_send trace point is adjusted so that
rqst->rq_xprt is not NULL when the trace event is recorded.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svc: Simplify ->xpo_secure_port

Clean up: Instead of returning a value that is used to set or clear
a bit, just make ->xpo_secure_port mangle that bit, and return void.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Consult max_qp_init_rd_atom when accepting connections

The target needs to return the lesser of the client's Inbound RDMA
Read Queue Depth (IRD), provided in the connection parameters, and
the local device's Outbound RDMA Read Queue Depth (ORD). The latter
limit is max_qp_init_rd_atom, not max_qp_rd_atom.

The svcrdma_ord value caps the ORD value for iWARP transports, which
do not exchange ORD/IRD values at connection time. Since no other
Linux kernel RDMA-enabled storage target sees fit to provide this
cap, I'm removing it here too.

initiator_depth is a u8, so ensure the computed ORD value does not
overflow that field.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Use pr_err to report Receive errors

Clean up: Other completion handlers use pr_err, not pr_warn.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Post Receives in the Receive completion handler

This change improves Receive efficiency by posting Receives only
on the same CPU that handles Receive completion. Improved latency
and throughput has been noted with this change.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Enqueue after setting XPT_CLOSE in completion handlers

I noticed the server was sometimes not closing the connection after
a flushed Send. For example, if the client responds with an RNR NAK
to a Reply from the server, that client might be deadlocked, and
thus wouldn't send any more traffic. Thus the server wouldn't have
any opportunity to notice the XPT_CLOSE bit has been set.

Enqueue the transport so that svcxprt notices the bit even if there
is no more transport activity after a flushed completion, QP access
error, or device removal event.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-By: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Estimate Send Queue depth properly

The rdma_rw API adjusts max_send_wr upwards during the
rdma_create_qp() call. If the ULP actually wants to take advantage
of these extra resources, it must increase the size of its send
completion queue (created before rdma_create_qp is called) and
increase its send queue accounting limit.

Use the new rdma_rw_mr_factor API to figure out the correct value
to use for the Send Queue and Send Completion Queue depths.

And, ensure that the chosen Send Queue depth for a newly created
transport does not overrun the QP WR limit of the underlying device.

Lastly, there's no longer a need to carry the Send Queue depth in
struct svcxprt_rdma, since the value is used only in the
svc_rdma_accept() path.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Limit RQ depth

Ensure that the chosen Receive Queue depth for a newly created
transport does not overrun the QP WR limit of the underlying device.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

sunrpc: Const-ify instances of struct svc_xprt_ops

Close an attack vector by moving the arrays of server-side transport
methods to read-only memory.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Clean up after converting svc_rdma_recvfrom to rdma_rw API

Clean up: Registration mode details are now handled by the rdma_rw
API, and thus can be removed from svcrdma.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Clean-up svc_rdma_unmap_dma

There's no longer a need to compare each SGE's lkey with the PD's
local_dma_lkey. Now that FRWR is gone, all DMA mappings are for
pages that were registered with this key.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove frmr cache

Clean up: Now that the svc_rdma_recvfrom path uses the rdma_rw API,
the details of Read sink buffer registration are dealt with by the
kernel's RDMA core. This cache is no longer used, and can be
removed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove unused Read completion handlers

Clean up:

The generic RDMA R/W API conversion of svc_rdma_recvfrom replaced
the Register, Read, and Invalidate completion handlers. Remove the
old ones, which are no longer used.

These handlers shared some helper code with svc_rdma_wc_send. Fold
the wc_common helper back into the one remaining completion handler.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Use generic RDMA R/W API in RPC Call path

The current svcrdma recvfrom code path has a lot of detail about
registration mode and the type of port (iWARP, IB, etc).

Instead, use the RDMA core's generic R/W API. This shares code with
other RDMA-enabled ULPs that manages the gory details of buffer
registration and the posting of RDMA Read Work Requests.

Since the Read list marshaling code is being replaced, I took the
opportunity to replace C structure-based XDR encoding code with more
portable code that uses pointer arithmetic.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove the req_map cache

req_maps are no longer used by the send path and can thus be removed.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove unused RDMA Write completion handler

Clean up. All RDMA Write completions are now handled by
svc_rdma_wc_write_ctx.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Use rdma_rw API in RPC reply path

The current svcrdma sendto code path posts one RDMA Write WR at a
time. Each of these Writes typically carries a small number of pages
(for instance, up to 30 pages for mlx4 devices). That means a 1MB
NFS READ reply requires 9 ib_post_send() calls for the Write WRs,
and one for the Send WR carrying the actual RPC Reply message.

Instead, use the new rdma_rw API. The details of Write WR chain
construction and memory registration are taken care of in the RDMA
core. svcrdma can focus on the details of the RPC-over-RDMA
protocol. This gives three main benefits:

1. All Write WRs for one RDMA segment are posted in a single chain.
As few as one ib_post_send() for each Write chunk.

2. The Write path can now use FRWR to register the Write buffers.
If the device's maximum page list depth is large, this means a
single Write WR is needed for each RPC's Write chunk data.

3. The new code introduces support for RPCs that carry both a Write
list and a Reply chunk. This combination can be used for an NFSv4
READ where the data payload is large, and thus is removed from the
Payload Stream, but the Payload Stream is still larger than the
inline threshold.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Introduce local rdma_rw API helpers

The plan is to replace the local bespoke code that constructs and
posts RDMA Read and Write Work Requests with calls to the rdma_rw
API. This shares code with other RDMA-enabled ULPs that manages the
gory details of buffer registration and posting Work Requests.

Some design notes:

o The structure of RPC-over-RDMA transport headers is flexible,
allowing multiple segments per Reply with arbitrary alignment,
each with a unique R_key. Write and Send WRs continue to be
built and posted in separate code paths. However, one whole
chunk (with one or more RDMA segments apiece) gets exactly
one ib_post_send and one work completion.

o svc_xprt reference counting is modified, since a chain of
rdma_rw_ctx structs generates one completion, no matter how
many Write WRs are posted.

o The current code builds the transport header as it is construct-
ing Write WRs. I've replaced that with marshaling of transport
header data items in a separate step. This is because the exact
structure of client-provided segments may not align with the
components of the server's reply xdr_buf, or the pages in the
page list. Thus parts of each client-provided segment may be
written at different points in the send path.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Eliminate RPCRDMA_SQ_DEPTH_MULT

The Send Queue depth is temporarily reduced to 1 SQE per credit. The
new rdma_rw API does an internal computation, during QP creation, to
increase the depth of the Send Queue to handle RDMA Read and Write
operations.

This change has to come before the NFSD code paths are updated to
use the rdma_rw API. Without this patch, rdma_rw_init_qp() increases
the size of the SQ too much, resulting in memory allocation failures
during QP creation.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: set XPT_CONG_CTRL flag for bc xprt

Same change as Kinglong Mee's fix for the TCP backchannel service.

Fixes: 5283b03ee5cd ("nfs/nfsd/sunrpc: enforce transport...")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

sunrpc: flag transports as having congestion control

NFSv4 requires a transport protocol with congestion control in most
cases.

On an IP network, that means that NFSv4 over UDP should be forbidden.

The situation with RDMA is a bit more nuanced, but most RDMA transports
are suitable for this. For now, we assume that all RDMA transports are
suitable, but we may need to revise that at some point.

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

svcrdma: Poll CQs in "workqueue" mode

svcrdma calls svc_xprt_put() in its completion handlers, which
currently run in IRQ context.

However, svc_xprt_put() is meant to be invoked in process context,
not in IRQ context. After the last transport reference is gone, it
directly calls a transport release function that expects to run in
process context.

Change the CQ polling modes to IB_POLL_WORKQUEUE so that svcrdma
invokes svc_xprt_put() only in process context. As an added benefit,
bottom half-disabled spin locking can be eliminated from I/O paths.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Combine list fields in struct svc_rdma_op_ctxt

Clean up: The free list and the dto_q list fields are never used at
the same time. Reduce the size of struct svc_rdma_op_ctxt by
combining these fields.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove unused sc_dto_q field

Clean up. Commit be99bb11400c ("svcrdma: Use new CQ API for
RPC-over-RDMA server send CQs") removed code that used the sc_dto_q
field, but neglected to remove sc_dto_q at the same time.

Fixes: be99bb11400c ("svcrdma: Use new CQ API for RPC-over- ...")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Clean up RPC-over-RDMA Reply header encoder

Replace C structure-based XDR decoding with pointer arithmetic.
Pointer arithmetic is considered more portable, and is used
throughout the kernel's existing XDR encoders. The gcc optimizer
generates similar assembler code either way.

Byte-swapping before a memory store on x86 typically results in an
instruction pipeline stall. Avoid byte-swapping when encoding a new
header.

svcrdma currently doesn't alter a connection's credit grant value
after the connection has been accepted, so it is effectively a
constant. Cache the byte-swapped value in a separate field.

Christoph suggested pulling the header encoding logic into the only
function that uses it.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

locking/atomic, kref: Add kref_read()

Since we need to change the implementation, stop exposing internals.

Provide kref_read() to read the current reference count; typically
used for debug messages.

Kills two anti-patterns:

atomic_read(&kref->refcount)
kref->refcount.counter

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

svcrdma: Break up dprintk format in svc_rdma_accept()

The current code results in:

Nov 7 14:50:19 klimt kernel: svcrdma: newxprt->sc_cm_id=ffff88085590c800,
newxprt->sc_pd=ffff880852a7ce00#012 cm_id->device=ffff88084dd20000,
sc_pd->device=ffff88084dd20000#012 cap.max_send_wr = 272#012
cap.max_recv_wr = 34#012 cap.max_send_sge = 32#012
cap.max_recv_sge = 32
Nov 7 14:50:19 klimt kernel: svcrdma: new connection ffff880855908000
accepted with the following attributes:#012 local_ip :
10.0.0.5#012 local_port#011 : 20049#012 remote_ip :
10.0.0.2#012 remote_port : 59909#012 max_sge : 32#012
max_sge_rd : 30#012 sq_depth : 272#012 max_requests :
32#012 ord : 16

Split up the output over multiple dprintks and take the opportunity
to fix the display of IPv6 addresses.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove svc_rdma_op_ctxt::wc_status

Clean up: Completion status is already reported in the individual
completion handlers. Save a few bytes in struct svc_rdma_op_ctxt.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove DMA map accounting

Clean up: sc_dma_used is not required for correct operation. It is
simply a debugging tool to report when svcrdma has leaked DMA maps.

However, manipulating an atomic has a measurable CPU cost, and DMA
map accounting specific to svcrdma will be meaningless once svcrdma
is converted to use the new generic r/w API.

A similar kind of debug accounting can be done simply by enabling
the IOMMU or by using CONFIG_DMA_API_DEBUG, CONFIG_IOMMU_DEBUG, and
CONFIG_IOMMU_LEAK.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove BH-disabled spin locking in svc_rdma_send()

svcrdma's current SQ accounting algorithm takes sc_lock and disables
bottom-halves while posting all RDMA Read, Write, and Send WRs.

This is relatively heavyweight serialization. And note that Write and
Send are already fully serialized by the xpt_mutex.

Using a single atomic_t should be all that is necessary to guarantee
that ib_post_send() is called only when there is enough space on the
send queue. This is what the other RDMA-enabled storage targets do.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

sunrpc: svc_age_temp_xprts_now should not call setsockopt non-tcp transports

This fixes the following panic that can occur with NFSoRDMA.

general protection fault: 0000 [#1] SMP
Modules linked in: rpcrdma ib_isert iscsi_target_mod ib_iser libiscsi
scsi_transport_iscsi ib_srpt target_core_mod ib_srp scsi_transport_srp
scsi_tgt ib_ipoib rdma_ucm ib_ucm ib_uverbs ib_umad rdma_cm ib_cm iw_cm
mlx5_ib ib_core intel_powerclamp coretemp kvm_intel kvm sg ioatdma
ipmi_devintf ipmi_ssif dcdbas iTCO_wdt iTCO_vendor_support pcspkr
irqbypass sb_edac shpchp dca crc32_pclmul ghash_clmulni_intel edac_core
lpc_ich aesni_intel lrw gf128mul glue_helper ablk_helper mei_me mei
ipmi_si cryptd wmi ipmi_msghandler acpi_pad acpi_power_meter nfsd
auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c sd_mod
crc_t10dif crct10dif_generic mgag200 i2c_algo_bit drm_kms_helper
syscopyarea sysfillrect sysimgblt ahci fb_sys_fops ttm libahci mlx5_core
tg3 crct10dif_pclmul drm crct10dif_common
ptp i2c_core libata crc32c_intel pps_core fjes dm_mirror dm_region_hash
dm_log dm_mod
CPU: 1 PID: 120 Comm: kworker/1:1 Not tainted 3.10.0-514.el7.x86_64 #1
Hardware name: Dell Inc. PowerEdge R320/0KM5PX, BIOS 2.4.2 01/29/2015
Workqueue: events check_lifetime
task: ffff88031f506dd0 ti: ffff88031f584000 task.ti: ffff88031f584000
RIP: 0010:[<ffffffff8168d847>] [<ffffffff8168d847>]
_raw_spin_lock_bh+0x17/0x50
RSP: 0018:ffff88031f587ba8 EFLAGS: 00010206
RAX: 0000000000020000 RBX: 20041fac02080072 RCX: ffff88031f587fd8
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 20041fac02080072
RBP: ffff88031f587bb0 R08: 0000000000000008 R09: ffffffff8155be77
R10: ffff880322a59b00 R11: ffffea000bf39f00 R12: 20041fac02080072
R13: 000000000000000d R14: ffff8800c4fbd800 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff880322a40000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3c52d4547e CR3: 00000000019ba000 CR4: 00000000001407e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Stack:
20041fac02080002 ffff88031f587bd0 ffffffff81557830 20041fac02080002
ffff88031f587c78 ffff88031f587c40 ffffffff8155ae08 000000010157df32
0000000800000001 ffff88031f587c20 ffffffff81096acb ffffffff81aa37d0
Call Trace:
[<ffffffff81557830>] lock_sock_nested+0x20/0x50
[<ffffffff8155ae08>] sock_setsockopt+0x78/0x940
[<ffffffff81096acb>] ? lock_timer_base.isra.33+0x2b/0x50
[<ffffffff8155397d>] kernel_setsockopt+0x4d/0x50
[<ffffffffa0386284>] svc_age_temp_xprts_now+0x174/0x1e0 [sunrpc]
[<ffffffffa03b681d>] nfsd_inetaddr_event+0x9d/0xd0 [nfsd]
[<ffffffff81691ebc>] notifier_call_chain+0x4c/0x70
[<ffffffff810b687d>] __blocking_notifier_call_chain+0x4d/0x70
[<ffffffff810b68b6>] blocking_notifier_call_chain+0x16/0x20
[<ffffffff815e8538>] __inet_del_ifa+0x168/0x2d0
[<ffffffff815e8cef>] check_lifetime+0x25f/0x270
[<ffffffff810a7f3b>] process_one_work+0x17b/0x470
[<ffffffff810a8d76>] worker_thread+0x126/0x410
[<ffffffff810a8c50>] ? rescuer_thread+0x460/0x460
[<ffffffff810b052f>] kthread+0xcf/0xe0
[<ffffffff810b0460>] ? kthread_create_on_node+0x140/0x140
[<ffffffff81696418>] ret_from_fork+0x58/0x90
[<ffffffff810b0460>] ? kthread_create_on_node+0x140/0x140
Code: ca 75 f1 5d c3 0f 1f 80 00 00 00 00 eb d9 66 0f 1f 44 00 00 0f 1f
44 00 00 55 48 89 e5 53 48 89 fb e8 7e 04 a0 ff b8 00 00 02 00 <f0> 0f
c1 03 89 c2 c1 ea 10 66 39 c2 75 03 5b 5d c3 83 e2 fe 0f
RIP [<ffffffff8168d847>] _raw_spin_lock_bh+0x17/0x50
RSP <ffff88031f587ba8>

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Fixes: c3d4879e ("sunrpc: Add a function to close temporary transports immediately")
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

IB/core: add support to create a unsafe global rkey to ib_create_pd

Instead of exposing ib_get_dma_mr to ULPs and letting them use it more or
less unchecked, this moves the capability of creating a global rkey into
the RDMA core, where it can be easily audited. It also prints a warning
everytime this feature is used as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: support Remote Invalidation

Support Remote Invalidation. A private message is exchanged with
the client upon RDMA transport connect that indicates whether
Send With Invalidation may be used by the server to send RPC
replies. The invalidate_rkey is arbitrarily chosen from among
rkeys present in the RPC-over-RDMA header's chunk lists.

Send With Invalidate improves performance only when clients can
recognize, while processing an RPC reply, that an rkey has already
been invalidated. That has been submitted as a separate change.

In the future, the RPC-over-RDMA protocol might support Remote
Invalidation properly. The protocol needs to enable signaling
between peers to indicate when Remote Invalidation can be used
for each individual RPC.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Server-side support for rpcrdma_connect_private

Prepare to receive an RDMA-CM private message when handling a new
connection attempt, and send a similar message as part of connection
acceptance.

Both sides can communicate their various implementation limits.
Implementations that don't support this sideband protocol ignore it.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Tail iovec leaves an orphaned DMA mapping

The ctxt's count field is overloaded to mean the number of pages in
the ctxt->page array and the number of SGEs in the ctxt->sge array.
Typically these two numbers are the same.

However, when an inline RPC reply is constructed from an xdr_buf
with a tail iovec, the head and tail often occupy the same page,
but each are DMA mapped independently. In that case, ->count equals
the number of pages, but it does not equal the number of SGEs.
There's one more SGE, for the tail iovec. Hence there is one more
DMA mapping than there are pages in the ctxt->page array.

This isn't a real problem until the server's iommu is enabled. Then
each RPC reply that has content in that iovec orphans a DMA mapping
that consists of real resources.

krb5i and krb5p always populate that tail iovec. After a couple
million sent krb5i/p RPC replies, the NFS server starts behaving
erratically. Reboot is needed to clear the problem.

Fixes: 9d11b51ce7c1 ("svcrdma: Fix send_reply() scatter/gather set-up")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Drain QP before freeing svcrdma_xprt

If the server has forced a disconnect, the associated QP has not
been moved to the Error state, and thus Receives are still posted.

Ensure Receives (and any other outstanding WRs) are drained to
release resources that can be freed during teardown of the
svcrdma_xprt.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Post Receives only for forward channel requests

Since backward direction support was added, the rq_depth was
increased to accommodate both forward and backward Receives.

But only forward Receives need to be posted after a connection
has been accepted. Receives for backward replies are posted as
needed by svc_rdma_bc_sendto().

This doesn't break anything, but it means some resources are
wasted.

Fixes: 03fe9931536f ('svcrdma: Define maximum number of ...')
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Support IPv6 with NFS/RDMA

Allow both IPv4 and IPv6 to bind same port at the same time,
restricts use of the IPv6 socket to IPv6 communication.

Changes from v1:
- Check rdma_set_afonly return value (suggested by Leon Romanovsky)

Changes from v2:
- Acked-by: Leon Romanovsky <leonro@mellanox.com>

Signed-off-by: Shirley Ma <shirley.ma@oracle.com>
Acked-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Use new CQ API for RPC-over-RDMA server send CQs

Calling ib_poll_cq() to sort through WCs during a completion is a
common pattern amongst RDMA consumers. Since commit 14d3a3b2498e
("IB: add a proper completion queue abstraction"), WC sorting can
be handled by the IB core.

By converting to this new API, svcrdma is made a better neighbor to
other RDMA consumers, as it allows the core to schedule the delivery
of completions more fairly amongst all active consumers.

This new API also aims each completion at a function that is
specific to the WR's opcode. Thus the ctxt->wr_op field and the
switch in process_context is replaced by a set of methods that
handle each completion type.

Because each ib_cqe carries a pointer to a completion method, the
core can now post operations on a consumer's QP, and handle the
completions itself.

The server's rdma_stat_sq_poll and rdma_stat_sq_prod metrics are no
longer updated.

As a clean up, the cq_event_handler, the dto_tasklet, and all
associated locking is removed, as they are no longer referenced or
used.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Use new CQ API for RPC-over-RDMA server receive CQs

Calling ib_poll_cq() to sort through WCs during a completion is a
common pattern amongst RDMA consumers. Since commit 14d3a3b2498e
("IB: add a proper completion queue abstraction"), WC sorting can
be handled by the IB core.

By converting to this new API, svcrdma is made a better neighbor to
other RDMA consumers, as it allows the core to schedule the delivery
of completions more fairly amongst all active consumers.

Because each ib_cqe carries a pointer to a completion method, the
core can now post operations on a consumer's QP, and handle the
completions itself.

svcrdma receive completions no longer use the dto_tasklet. Each
polled Receive WC is now handled individually in soft IRQ context.

The server transport's rdma_stat_rq_poll and rdma_stat_rq_prod
metrics are no longer updated.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Make RDMA_ERROR messages work

Fix several issues with svc_rdma_send_error():

- Post a receive buffer to replace the one that was consumed by
the incoming request
- Posting a send should use DMA_TO_DEVICE, not DMA_FROM_DEVICE
- No need to put_page _and_ free pages in svc_rdma_put_context
- Make sure the sge is set up completely in case the error
path goes through svc_rdma_unmap_dma()
- Replace the use of ENOSYS, which has a reserved meaning

Related fixes in svc_rdma_recvfrom():

- Don't leak the ctxt associated with the incoming request
- Don't close the connection after sending an error reply
- Let svc_rdma_send_error() figure out the right header error code

As a last clean up, move svc_rdma_send_error() to svc_rdma_sendto.c
with other similar functions. There is some common logic in these
functions that could someday be combined to reduce code duplication.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Tested-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: svc_rdma_post_recv() should close connection on error

Clean up: Most svc_rdma_post_recv() call sites close the transport
connection when a receive cannot be posted. Wrap that in a common
helper.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Tested-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svc_rdma: use local_dma_lkey

We now alwasy have a per-PD local_dma_lkey available. Make use of that
fact in svc_rdma and stop registering our own MR.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Acked-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Add class for RDMA backwards direction transport

To support the server-side of an NFSv4.1 backchannel on RDMA
connections, add a transport class that enables backward
direction messages on an existing forward channel connection.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Define maximum number of backchannel requests

Extra resources for handling backchannel requests have to be
pre-allocated when a transport instance is created. Set up
additional fields in svcxprt_rdma to track these resources.

The max_requests fields are elements of the RPC-over-RDMA
protocol, so they should be u32. To ensure that unsigned
arithmetic is used everywhere, some other fields in the
svcxprt_rdma struct are updated.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Remove last two __GFP_NOFAIL call sites

Clean up.

These functions can otherwise fail, so check for page allocation
failures too.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Add gfp flags to svc_rdma_post_recv()

svc_rdma_post_recv() allocates pages for receive buffers on-demand.
It uses GFP_KERNEL so the allocator tries hard, and may sleep. But
I'm about to add a call to svc_rdma_post_recv() from a function
that may not sleep.

Since all svc_rdma_post_recv() call sites can tolerate its failure,
allow it to fail if the page allocator returns nothing. Longer term,
receive buffers, being a finite resource per-connection, should be
pre-allocated and re-used.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Improve allocation of struct svc_rdma_req_map

To ensure this allocation cannot fail and will not sleep,
pre-allocate the req_map structures per-connection.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Improve allocation of struct svc_rdma_op_ctxt

When the maximum payload size of NFS READ and WRITE was increased
by commit cc9a903d915c ("svcrdma: Change maximum server payload back
to RPCSVC_MAXPAYLOAD"), the size of struct svc_rdma_op_ctxt
increased to over 6KB (on x86_64). That makes allocating one of
these from a kmem_cache more likely to fail in situations when
system memory is exhausted.

Since I'm about to add a caller where this allocation must always
work _and_ it cannot sleep, pre-allocate ctxts for each connection.

Another motivation for this change is that NFSv4.x servers are
required by specification not to drop NFS requests. Pre-allocating
memory resources reduces the likelihood of a drop.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Clean up process_context()

Be sure the completed ctxt is put in every path.

The xprt enqueue can take a while, so put the completed ctxt back
in circulation _before_ enqueuing the xprt.

Remove/disable debugging.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Clean up rdma_create_xprt()

kzalloc is used here, so setting the atomic fields to zero is
unnecessary. sc_ord is set again in handle_connect_req. The other
fields are re-initialized in svc_rdma_accept().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Bruce Fields <bfields@fieldses.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

xprtrdma: Avoid calling ib_query_device

Instead, use the cached copy of the attributes present on the device.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Add backward direction service for RPC/RDMA transport

On NFSv4.1 mount points, the Linux NFS client uses this transport
endpoint to receive backward direction calls and route replies back
to the NFSv4.1 server.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Tested-By: Devesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

svcrdma: Port to new memory registration API

Instead of maintaining a fastreg page list, keep an sg table
and convert an array of pages to a sg list. Then call ib_map_mr_sg
and construct ib_reg_wr.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Tested-by: Selvin Xavier <selvin.xavier@avagotech.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/cma: Add support for network namespaces

Add support for network namespaces in the ib_cma module. This is
accomplished by:

1. Adding network namespace parameter for rdma_create_id. This parameter is
used to populate the network namespace field in rdma_id_private.
rdma_create_id keeps a reference on the network namespace.
2. Using the network namespace from the rdma_id instead of init_net inside
of ib_cma, when listening on an ID and when looking for an ID for an
incoming request.
3. Decrementing the reference count for the appropriate network namespace
when calling rdma_destroy_id.

In order to preserve the current behavior init_net is passed when calling
from other modules.

Signed-off-by: Guy Shapiro <guysh@mellanox.com>
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Yotam Kenneth <yotamke@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: limit FRMR page list lengths to device max

Svcrdma was incorrectly allocating fastreg MRs and page lists using
RPCSVC_MAXPAGES, which can exceed the device capabilities. So limit
the depth to the minimum of RPCSVC_MAXPAGES and xprt->sc_frmr_pg_list_len.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

xprtrdma, svcrdma: Convert to ib_alloc_mr

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Use max_sge_rd for destination read depths

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Change maximum server payload back to RPCSVC_MAXPAYLOAD

Both commit 0380a3f375 ("svcrdma: Add a separate "max data segs"
macro for svcrdma") and commit 7e5be28827bf ("svcrdma: advertise
the correct max payload") are incorrect. This commit reverts both
changes, restoring the server's maximum payload size to 1MB.

Commit 7e5be28827bf based the server's maximum payload on the
_client's_ RPCRDMA_MAX_DATA_SEGS value. That was wrong.

Commit 0380a3f375 tried to fix this so that the client maximum
payload size could be raised without affecting the server, but
managed to confuse matters more on the server side.

More importantly, limiting the advertised maximum payload size was
meant to be a workaround, not the actual fix. We need to revisit

https://bugzilla.linux-nfs.org/show_bug.cgi?id=270

A Linux client on a platform with 64KB pages can overrun and crash
an x86_64 NFS/RDMA server when the r/wsize is 1MB. An x86/64 Linux
client seems to work fine using 1MB reads and writes when the Linux
server's maximum payload size is restored to 1MB.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=270
Fixes: 0380a3f375 ("svcrdma: Add a separate "max data segs" macro")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove svc_rdma_fastreg()

Commit 0bf4828983df ("svcrdma: refactor marshalling logic") removed
the last call site for svc_rdma_fastreg().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

NFS/RDMA Release resources in svcrdma when device is removed

When removing underlying RDMA device, the rmmod will hang forever if there
are any outstanding NFS/RDMA client mounts. The outstanding NFS/RDMA counts
could also prevent the server from shutting down. Further debugging shows
that the existing connections are not teared down and resource are not
released when receiving RDMA_CM_EVENT_DEVICE_REMOVAL event. It seems the
original code missing svc_xprt_put() in RDMA_CM_EVENT_REMOVAL event handler
thus svc_xprt_free is never invoked to release the existing connection
resources.

The patch has been passed removing, adding device back and forth without
stopping NFS/RDMA service. This will also allow a device to be unplugged
and swapped out without shutting down NFS service.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=252
Signed-off-by: Shirley Ma <shirley.ma@oracle.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

IB/core: Change ib_create_cq to use struct ib_cq_init_attr

Currently, ib_create_cq uses cqe and comp_vecotr instead
of the extendible ib_cq_init_attr struct.

Earlier patches already changed the vendors to work with
ib_cq_init_attr. This patch changes the consumers too.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Add a separate "max data segs macro for svcrdma

The server and client maximum are architecturally independent.
Allow changing one without affecting the other.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Replace GFP_KERNEL in a loop with GFP_NOFAIL

At the 2015 LSF/MM, it was requested that memory allocation
call sites that request GFP_KERNEL allocations in a loop should be
annotated with __GFP_NOFAIL.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Keep rpcrdma_msg fields in network byte-order

Fields in struct rpcrdma_msg are __be32. Don't byte-swap these
fields when decoding RPC calls and then swap them back for the
reply. For the most part, they can be left alone.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

IB/core: Change rdma_protocol_iboe to roce

After discussion upstream, it was agreed to transition the usage of iboe
in the kernel to roce. This keeps our terminology consistent with what
was finalized in the IBTA Annex 16 and IBTA Annex 17 publications.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

xprtrdma, svcrdma: Switch to generic logging helpers

Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Anna Schumaker <anna.schumaker@netapp.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

IB/Verbs: Reform IB-ulp xprtrdma

Use raw management helpers to reform IB-ulp xprtrdma.

Signed-off-by: Michael Wang <yun.wang@profitbricks.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Tested-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

svcrdma: Plant reader function in struct svcxprt_rdma

The RDMA reader function doesn't change once an svcxprt_rdma is
instantiated. Instead of checking sc_devcap during every incoming
RPC, set the reader function once when the connection is accepted.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Scrub BUG_ON() and WARN_ON() call sites

Current convention is to avoid using BUG_ON() in places where an
oops could cause complete system failure.

Replace BUG_ON() call sites in svcrdma with an assertion error
message and allow execution to continue safely.

Some BUG_ON() calls are removed because they have never fired in
production (that we are aware of).

Some WARN_ON() calls are also replaced where a back trace is not
helpful; e.g., in a workqueue task.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Remove unused variable

Nit: remove an unused variable to squelch a compiler warning.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: advertise the correct max payload

Svcrdma currently advertises 1MB, which is too large. The correct value
is the minimum of RPCSVC_MAXPAYLOAD and the max scatter-gather allowed
in an NFSRDMA IO chunk * the host page size. This bug is usually benign
because the Linux X64 NFSRDMA client correctly limits the payload size to
the correct value (64*4096 = 256KB). But if the Linux client is PPC64
with a 64KB page size, then the client will indeed use a payload size
that will overflow the server.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: remove rdma_create_qp() failure recovery logic

In svc_rdma_accept(), if rdma_create_qp() fails, there is useless
logic to try and call rdma_create_qp() again with reduced sge depths.
The assumption, I guess, was that perhaps the initial sge depths
chosen were too big. However they initial depths are selected based
on the rdma device attribute max_sge returned from ib_query_device().
If rdma_create_qp() fails, it would not be because the max_send_sge and
max_recv_sge values passed in exceed the device's max. So just remove
this code.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Select NFSv4.1 backchannel transport based on forward channel

The current code always selects XPRT_TRANSPORT_BC_TCP for the back
channel, even when the forward channel was not TCP (eg, RDMA). When
a 4.1 mount is attempted with RDMA, the server panics in the TCP BC
code when trying to send CB_NULL.

Instead, construct the transport protocol number from the forward
channel transport or'd with XPRT_TRANSPORT_BC. Transports that do
not support bi-directional RPC will not have registered a "BC"
transport, causing create_backchannel_client() to fail immediately.

Fixes: https://bugzilla.linux-nfs.org/show_bug.cgi?id=265
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: refactor marshalling logic

This patch refactors the NFSRDMA server marshalling logic to
remove the intermediary map structures. It also fixes an existing bug
where the NFSRDMA server was not minding the device fast register page
list length limitations.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>

NFSD: Ignore client's source port on RDMA transports

An NFS/RDMA client's source port is meaningless for RDMA transports.
The transport layer typically sets the source port value on the
connection to a random ephemeral port.

Currently, NFS server administrators must specify the "insecure"
export option to enable clients to access exports via RDMA.

But this means NFS clients can access such an export via IP using an
ephemeral port, which may not be desirable.

This patch eliminates the need to specify the "insecure" export
option to allow NFS/RDMA clients access to an export.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=250
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: fix printk when memory allocation fails

It retries in 1s, not 1000 jiffies.

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

svcrpc: make svc_xprt_received static

Note this isn't used outside svc_xprt.c.

May as well move it so we don't need a declaration while we're here.

Also remove an outdated comment.

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

svcrdma: Cleanup sparse warnings in the svcrdma module

The svcrdma transport was un-marshalling requests in-place. This resulted
in sparse warnings due to __beXX data containing both NBO and HBO data.

The code has been restructured to do byte-swapping as the header is
parsed instead of when the header is validated immediately after receipt.

Also moved extern declarations for the workqueue and memory pools to the
private header file.

Signed-off-by: Tom Tucker <tom@ogc.us>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: create svc_xprt in proper network namespace

This patch makes svc_xprt inherit network namespace link from its socket.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules

These files are non modular, but need to export symbols using
the macros now living in export.h -- call out the include so
that things won't break when we remove the implicit presence
of module.h from everywhere.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

net: remove interrupt.h inclusion from netdevice.h

* remove interrupt.g inclusion from netdevice.h -- not needed
* fixup fallout, add interrupt.h and hardirq.h back where needed.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

RDMA/cma: Pass QP type into rdma_create_id()

The RDMA CM currently infers the QP type from the port space selected
by the user. In the future (eg with RDMA_PS_IB or XRC), there may not
be a 1-1 correspondence between port space and QP type. For netlink
export of RDMA CM state, we want to export the QP type to userspace,
so it is cleaner to explicitly associate a QP type to an ID.

Modify rdma_create_id() to allow the user to specify the QP type, and
use it to make our selections of datagram versus connected mode.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

treewide: fix a few typos in comments

- kenrel -> kernel
- whetehr -> whether
- ttt -> tt
- sss -> ss

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

SUNRPC: Remove resource leak in svc_rdma_send_error()

We leak the memory allocated to 'ctxt' when we return after
'ib_dma_mapping_error()' returns !=0.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

SUNRPC: Remove resource leak in svc_rdma_send_error()

We leak the memory allocated to 'ctxt' when we return after
'ib_dma_mapping_error()' returns !=0.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

sunrpc/xprtrdma: clean up workqueue usage

* Create and use svc_rdma_wq instead of using the system workqueue and
flush_scheduled_work(). This workqueue is necessary to serve as
flushing domain for rdma->sc_work which is used to destroy itself
and thus can't be flushed explicitly.

* Replace cancel_delayed_work() + flush_scheduled_work() with
cancel_delayed_work_sync().

* Implement synchronous connect in xprt_rdma_connect() using
flush_delayed_work() on the rdma_connect work instead of using
flush_scheduled_work().

This is to prepare for the deprecation and removal of
flush_scheduled_work().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Cleanup DMA unmapping in error paths.

There are several error paths in the code that do not unmap DMA. This
patch adds calls to svc_rdma_unmap_dma to free these DMA contexts.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: Change DMA mapping logic to avoid the page_address kernel API

There was logic in the send path that assumed that a page containing data
to send to the client has a KVA. This is not always the case and can result
in data corruption when page_address returns zero and we end up DMA mapping
zero.

This patch changes the bus mapping logic to avoid page_address() where
necessary and converts all calls from ib_dma_map_single to ib_dma_map_page
in order to keep the map/unmap calls symmetric.

Signed-off-by: Tom Tucker <tom@ogc.us>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

sunrpc: Pull net argument downto svc_create_socket

After this the socket creation in it knows the context.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

svcrdma: RDMA support not yet compatible with RPC6

RPC6 requires that it be possible to create endpoints that listen
exclusively for IPv4 or IPv6 connection requests. This is not currently
supported by the RDMA API.

This fixes a server RDMA regression introduced by 37498292a "NFSD:
Create PF_INET6 listener in write_ports".

Signed-off-by: Tom Tucker<tom@opengridcomputing.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

headers: remove sched.h from interrupt.h

After m68k's task_thread_info() doesn't refer to current,
it's possible to remove sched.h from interrupt.h and not break m68k!
Many thanks to Heiko Carstens for allowing this.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

svcrdma: fix error handling of rdma_alloc_frmr()

ib_alloc_fast_reg_mr() and ib_alloc_fast_reg_page_list() returns
ERR_PTR() and not NULL. Compile tested only.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

svcrdma: dma unmap the correct length for the RPCRDMA header page.

The svcrdma module was incorrectly unmapping the RPCRDMA header page.
On IBM pserver systems this causes a resource leak that results in
running out of bus address space (10 cthon iterations will reproduce it).
The code was mapping the full page but only unmapping the actual header
length. The fix is to only map the header length.

I also cleaned up the use of ib_dma_map_page() calls since the unmap
logic always uses ib_dma_unmap_single(). I made these symmetrical.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

svcrdma: clean up error paths.

These fixes resolved crashes due to resource leak BUG_ON checks. The
resource leaks were detected by introducing asynchronous transport errors.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

net: Make static

Sparse asked whether these could be static.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sunrpc: fix warning in net/sunrpc/xprtrdma/svc_rdma_transport.c

this warning:

net/sunrpc/xprtrdma/svc_rdma_transport.c: In function ‘svc_rdma_accept’:
net/sunrpc/xprtrdma/svc_rdma_transport.c:830: warning: ‘dma_mr_acc’ may be used uninitialized in this function

triggers because GCC does not recognize the (correct) flow connection
between need_dma_mr and dma_mr_acc.

Annotate it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: replace NIPQUAD() in net/*/

Using NIPQUAD() with NIPQUAD_FMT, %d.%d.%d.%d or %u.%u.%u.%u
can be replaced with %pI4

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

svcrdma: Fix IRD/ORD polarity

The inititator/responder resources in the event have been swapped. They
no represent what the local peer would set their values to in order to
match the peer. Note that iWARP does not exchange these on the wire and
the provider is simply putting in the local device max.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Update svc_rdma_send_error to use DMA LKEY

Update the svc_rdma_send_error code to use the DMA LKEY which is valid
regardless of the memory registration strategy in use.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Modify the RPC reply path to use FRMR when available

Use FRMR to map local RPC reply data. This allows RDMA_WRITE to send reply
data using a single WR. The FRMR is invalidated by linking the LOCAL_INV WR
to the RDMA_SEND message used to complete the reply.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Modify the RPC recv path to use FRMR when available

RPCRDMA requests that specify a read-list are fetched with RDMA_READ. Using
an FRMR to map the data sink improves NFSRDMA security on transports that
place the RDMA_READ data sink LKEY on the wire because the valid lifetime
of the MR is only the duration of the RDMA_READ. The LKEY is invalidated
when the last RDMA_READ WR completes.

Mapping the data sink also allows for very large amounts to data to be
fetched with a single WR, so if the client is also using FRMR, the entire
RPC read-list can be fetched with a single WR.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Add support to svc_rdma_send to handle chained WR

WR can be submitted as linked lists of WR. Update the svc_rdma_send
routine to handle WR chains. This will be used to submit a WR that
uses an FRMR with another WR that invalidates the FRMR.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Modify post recv path to use local dma key

Update the svc_rdma_post_recv routine to use the adapter's global LKEY
instead of sc_phys_mr which is only valid when using a DMA MR.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Add a service to register a Fast Reg MR with the device

Fast Reg MR introduces a new WR type. Add a service to register the
region with the adapter and update the completion handling to support
completions with a NULL WR context.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Query device for Fast Reg support during connection setup

Query the device capabilities in the svc_rdma_accept function to determine
what advanced memory management capabilities are supported by the device.
Based on the query, select the most secure model available given the
requirements of the transport and capabilities of the adapter.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Add FRMR get/put services

Add services for the allocating, freeing, and unmapping Fast Reg MR. These
services will be used by the transport connection setup, send and receive
routines.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Fix race between svc_rdma_recvfrom thread and the dto_tasklet

RDMA_READ completions are kept on a separate queue from the general
I/O request queue. Since a separate lock is used to protect the RDMA_READ
completion queue, a race exists between the dto_tasklet and the
svc_rdma_recvfrom thread where the dto_tasklet sets the XPT_DATA
bit and adds I/O to the read-completion queue. Concurrently, the
recvfrom thread checks the generic queue, finds it empty and resets
the XPT_DATA bit. A subsequent svc_xprt_enqueue will fail to enqueue
the transport for I/O and cause the transport to "stall".

The fix is to protect both lists with the same lock and set the XPT_DATA
bit with this lock held.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

svcrdma: Change WR context get/put to use the kmem cache

Change the WR context pool to be shared across mount points. This
reduces the RDMA transport memory footprint significantly since
idle mounts don't consume WR context memory.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Limit ORD based on client's advertised IRD

When adapters have differing IRD limits, the RDMA transport will fail to
connect properly. The RDMA transport should use the client's advertised
inbound read limit when computing its outbound read limit. For iWARP
transports, there is currently no standard for exchanging IRD/ORD
during connection establishment so the 'responder_resources' field in the
connect event is the local device's limit. The RDMA transport can be
configured to use a smaller ORD by writing the desired number to the
/proc/sys/sunrpc/svc_rdma/max_outbound_read_requests file.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Remove unneeded spin locks from __svc_rdma_free

At the time __svc_rdma_free is called, we are guaranteed that all references
to this transport are gone. There is, therefore, no need to protect the
resource lists with a spin lock.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Add dma map count and WARN_ON

Add a dma map count in order to verify that all DMA mapping resources
have been freed when the transport is closed.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Move the DMA unmap logic to the CQ handler

Separate DMA unmap from context destruction and perform DMA unmapping
in the SQ/RQ CQ reap functions. This is necessary to support software
based RDMA implementations that actually copy the data in their
ib_dma_unmap callback functions and architectures that don't have
cache coherent I/O busses.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Use RPC reply map for RDMA_WRITE processing

Use the new svc_rdma_req_map data type for mapping the client side memory
to the server side memory. Move the DMA mapping to the context pointed to
by each WR individually so that it is unmapped after the WR completes.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Add a type for keeping NFS RPC mapping

Create a new data structure to hold the remote client address space
to local server address space mapping.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Change svc_rdma_send_error return type to void

The svc_rdma_send_error function is called when an RPCRDMA protocol
error is detected. This function attempts to post an error reply message.
Since an error posting to a transport in error is ignored, change
the return type to void.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Copy transport address and arm CQ before calling rdma_accept

This race was found by inspection. Messages can be received from the peer
immediately following the rdma_accept call, however, the CQ have not yet
been armed and the transport address has not yet been set.

Set the transport address in the connect request handler and arm the CQ
prior to calling rdma_accept.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Use ib verbs version of dma_unmap

Use the ib_verbs version of the dma_unmap service in the
svc_rdma_put_context function. This should support providers
using software rdma.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Cleanup queued, but unprocessed I/O in svc_rdma_free

When the transport is closing, the DTO tasklet may queue data
that never gets processed. Clean up resources associated with
this I/O.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Move the QP and cm_id destruction to svc_rdma_free

Move the destruction of the QP and CM_ID to the free path so that the
QP cleanup code doesn't race with the dto_tasklet handling flushed WR.
The QP reference is not needed because we now have a reference for
every WR.

Also add a guard in the SQ and RQ completion handlers to ignore
calls generated by some providers when the QP is destroyed.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Add reference for each SQ/RQ WR

Add a reference on the transport for every outstanding WR.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Move destroy to kernel thread

Some providers may wait while destroying adapter resources.
Since it is possible that the last reference is put on the
dto_tasklet, the actual destroy must be scheduled as a work item.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Shrink scope of spinlock on RQ CQ

The rq_cq_reap function is only called from the dto_tasklet. The
only resource shared with other threads is the sc_rq_dto_q. Move the
spin lock to protect only this list.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Use standard Linux lists for context cache

Replace the one-off linked list implementation used to implement the
context cache with the standard Linux list_head lists. Add a context
counter to catch resource leaks. A WARN_ON will be added later to
ensure that we've freed all contexts.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Simplify RDMA_READ deferral buffer management

An NFS_WRITE requires a set of RDMA_READ requests to fetch the write
data from the client. There are two principal pieces of data that
need to be tracked: the list of pages that comprise the completed RPC
and the SGE of dma mapped pages to refer to this list of pages. Previously
this whole bit was managed as a linked list of contexts with the
context containing the page list buried in this list. This patch
simplifies this processing by not keeping a linked list, but rather only
a pionter from the last submitted RDMA_READ's context to the context
that maps the set of pages that describe the RPC. This significantly
simplifies this code path. SGE contexts are cleaned up inline in the DTO
path instead of at read completion time.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Remove unused READ_DONE context flags bit

The RDMACTXT_F_READ_DONE bit is not longer used. Remove it.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Fix error handling during listening endpoint creation

A listening endpoint isn't known to the generic transport switch until
the svc_create_xprt function returns without error. Calling
svc_xprt_put within the xpo_create function causes the module reference
count to be erroneously decremented.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Free context on ib_post_recv error

If there is an error posting the recv WR to the RQ, free the
context associated with the WR. This would leak a context when
asynchronous errors occurred on the transport while conccurent threads
were processing their RPC.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Add put of connection ESTABLISHED reference in rdma_cma_handler

The svcrdma transport takes a reference when it gets the ESTABLISHED
event from the provider. This reference is supposed to be removed when
the DISCONNECT event is received, however, the call to svc_xprt_put
was missing in the switch statement. This results in the memory
associated with the transport never being freed.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Fix return value in svc_rdma_send

Fix the return value on close to -ENOTCONN so caller knows to free context.
Also if a thread is waiting for free SQ space, check for close when waking
to avoid posting WR to a closing transport.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Fix race with dto_tasklet in svc_rdma_send

The svc_rdma_send function will attempt to reap SQ WR to make room for
a new request if it finds the SQ full. This function races with the
dto_tasklet that also reaps SQ WR. To avoid polling and arming the CQ
unnecessarily move the test_and_clear_bit of the RDMAXPRT_SQ_PENDING
flag and arming of the CQ to the sq_cq_reap function.

Refactor the rq_cq_reap function to match sq_cq_reap so that the
code is easier to follow.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

svcrdma: Simplify receive buffer posting

The svcrdma transport provider currently allocates receive buffers
to the RQ through the xpo_release_rqst method. This approach is overly
complicated since it means that the rqstp rq_xprt_ctxt has to be
selectively set based on whether the RPC is going to be processed
immediately or deferred. Instead, just post the receive buffer when
we are certain that we are replying in the send_reply function.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

SVCRDMA: Add check for XPT_CLOSE in svc_rdma_send

SVCRDMA: Add check for XPT_CLOSE in svc_rdma_send

The svcrdma transport can crash if a send is waiting for an
empty SQ slot and the connection is closed due to an asynchronous error.
The crash is caused when svc_rdma_send attempts to send on a deleted
QP.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

SVCRDMA: Add xprt refs to fix close/unmount crash

RDMA connection shutdown on an SMP machine can cause a kernel crash due
to the transport close path racing with the I/O tasklet.

Additional transport references were added as follows:
- A reference when on the DTO Q to avoid having the transport
deleted while queued for I/O.
- A reference while there is a QP able to generate events.
- A reference until the DISCONNECTED event is received on the CM ID

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

rdma: SVCRDMA Core Transport Services

This file implements the core transport data management and I/O
path. The I/O path for RDMA involves receiving callbacks on interrupt
context. Since all the svc transport locks are _bh locks we enqueue the
transport on a list, schedule a tasklet to dequeue data indications from
the RDMA completion queue. The tasklet in turn takes _bh locks to
enqueue receive data indications on a list for the transport. The
svc_rdma_recvfrom transport function dequeues data from this list in an
NFSD thread context.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Neil Brown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>