nvme-multipath: pass queue_limits to blk_alloc_disk

The multipath disk starts out with the stacking default limits.
The one interesting part here is that blk_set_stacking_limits
sets the max_zone_append_sectorts to UINT_MAX, which fails the
validation for non-zoned devices. With the old one call per
limit scheme this was fine because no one verified this weird
mismatch and it was fixed by blk_stack_limits a little later
before I/O could be issued.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

block: pass a queue_limits argument to blk_alloc_disk

Pass a queue_limits to blk_alloc_disk and apply it if non-NULL. This
will allow allocating queues with valid queue limits instead of setting
the values one at a time later.

Also change blk_alloc_disk to return an ERR_PTR instead of just NULL
which can't distinguish errors.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Link: https://lore.kernel.org/r/20240215071055.2201424-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: use ctrl state accessor

The ctrl->state value is updated in another thread using WRITE_ONCE, so
ensure all the readers use the appropriate accessor.

Reviewed-by: Sagi Grimberg <sagi@grmberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

nvme: rename ns attribute group

Drop the 'id' part of the attribute group name because we want to expose
non 'id' related attributes via the ns attribute group.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

nvme: improved uring polling

Drivers can poll requests directly, so use that. We just need to ensure
the driver's request was allocated from a polled hctx, so a special
driver flag is added to struct io_uring_cmd.

The allows unshared and multipath namespaces to use the same polling
callback, and multipath is guaranteed to get the same queue as the
command was submitted on. Previously multipath polling might check a
different path and poll the wrong info.

The other bonus is we don't need a bio payload in order to poll,
allowing commands like 'flush' and 'write zeroes' to be submitted on the
same high priority queue as read and write commands.

Finally, using the request based polling skips the unnecessary bio
overhead.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230612190343.2087040-3-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-mpath: fix I/O failure with EAGAIN when failing over I/O

It is possible that the next available path we failover to, happens to
be frozen (for example if it is during connection establishment). If
the original I/O was set with NOWAIT, this cause the I/O to unnecessarily
fail because the request queue cannot be entered, hence the I/O fails with
EAGAIN.

The NOWAIT restriction that was originally set for the I/O is no longer
relevant or needed because this is the nvme requeue context. Hence we
clear the REQ_NOWAIT flag when failing over I/O.

This fix a simple test case of nvme controller reset during I/O when the
multipath device that has only a single path and I/O fails with "Resource
temporarily unavailable" errno. Note that this reproduces with io_uring
which by default sets IOCB_NOWAIT by default.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

block: replace fmode_t with a block-specific type for block open flags

The only overlap between the block open flags mapped into the fmode_t and
other uses of fmode_t are FMODE_READ and FMODE_WRITE. Define a new
blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and
->ioctl and stop abusing fmode_t.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the unused mode argument to ->release

The mode argument to the ->release block_device_operation is never used,
so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: pass a gendisk to ->open

->open is only called on the whole device. Make that explicit by
passing a gendisk instead of the block_device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: don't call blk_mark_disk_dead in nvme_mpath_remove_disk

nvme_mpath_remove_disk is called after del_gendisk, at which point a
blk_mark_disk_dead call doesn't make any sense.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>

block: count 'ios' and 'sectors' when io is done for bio-based device

While using iostat for raid, I observed very strange 'await'
occasionally, and turns out it's due to that 'ios' and 'sectors' is
counted in bdev_start_io_acct(), while 'nsecs' is counted in
bdev_end_io_acct(). I'm not sure why they are ccounted like that
but I think this behaviour is obviously wrong because user will get
wrong disk stats.

Fix the problem by counting 'ios' and 'sectors' when io is done, like
what rq-based device does.

Fixes: 394ffa503bc4 ("blk: introduce generic io stat accounting help function")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230223091226.1135678-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: handle bio_split_to_limits() NULL return

This can't happen right now, but in preparation for allowing
bio_split_to_limits() returning NULL if it ended the bio, check for it
in all the callers.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: support io stats on the mpath device

Our mpath stack device is just a shim that selects a bottom namespace
and submits the bio to it without any fancy splitting. This also means
that we don't clone the bio or have any context to the bio beyond
submission. However it really sucks that we don't see the mpath device
io stats.

Given that the mpath device can't do that without adding some context
to it, we let the bottom device do it on its behalf (somewhat similar
to the approach taken in nvme_trace_bio_complete).

When the IO starts, we account the request for multipath IO stats using
REQ_NVME_MPATH_IO_STATS nvme_request flag to avoid queue io stats disable
in the middle of the request.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>

nvme: fix SRCU protection of nvme_ns_head list

Walking the nvme_ns_head siblings list is protected by the head's srcu
in nvme_ns_head_submit_bio() but not nvme_mpath_revalidate_paths().
Removing namespaces from the list also fails to synchronize the srcu.
Concurrent scan work can therefore cause use-after-frees.

Hold the head's srcu lock in nvme_mpath_revalidate_paths() and
synchronize with the srcu, not the global RCU, in nvme_ns_remove().

Observed the following panic when making NVMe/RDMA connections
with native multipath on the Rocky Linux 8.6 kernel
(it seems the upstream kernel has the same race condition).
Disassembly shows the faulting instruction is cmp 0x50(%rdx),%rcx;
computing capacity != get_capacity(ns->disk).
Address 0x50 is dereferenced because ns->disk is NULL.
The NULL disk appears to be the result of concurrent scan work
freeing the namespace (note the log line in the middle of the panic).

[37314.206036] BUG: unable to handle kernel NULL pointer dereference at 0000000000000050
[37314.206036] nvme0n3: detected capacity change from 0 to 11811160064
[37314.299753] PGD 0 P4D 0
[37314.299756] Oops: 0000 [#1] SMP PTI
[37314.299759] CPU: 29 PID: 322046 Comm: kworker/u98:3 Kdump: loaded Tainted: G W X --------- - - 4.18.0-372.32.1.el8test86.x86_64 #1
[37314.299762] Hardware name: Dell Inc. PowerEdge R720/0JP31P, BIOS 2.7.0 05/23/2018
[37314.299763] Workqueue: nvme-wq nvme_scan_work [nvme_core]
[37314.299783] RIP: 0010:nvme_mpath_revalidate_paths+0x26/0xb0 [nvme_core]
[37314.299790] Code: 1f 44 00 00 66 66 66 66 90 55 53 48 8b 5f 50 48 8b 83 c8 c9 00 00 48 8b 13 48 8b 48 50 48 39 d3 74 20 48 8d 42 d0 48 8b 50 20 <48> 3b 4a 50 74 05 f0 80 60 70 ef 48 8b 50 30 48 8d 42 d0 48 39 d3
[37315.058803] RSP: 0018:ffffabe28f913d10 EFLAGS: 00010202
[37315.121316] RAX: ffff927a077da800 RBX: ffff92991dd70000 RCX: 0000000001600000
[37315.206704] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff92991b719800
[37315.292106] RBP: ffff929a6b70c000 R08: 000000010234cd4a R09: c0000000ffff7fff
[37315.377501] R10: 0000000000000001 R11: ffffabe28f913a30 R12: 0000000000000000
[37315.462889] R13: ffff92992716600c R14: ffff929964e6e030 R15: ffff92991dd70000
[37315.548286] FS: 0000000000000000(0000) GS:ffff92b87fb80000(0000) knlGS:0000000000000000
[37315.645111] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[37315.713871] CR2: 0000000000000050 CR3: 0000002208810006 CR4: 00000000000606e0
[37315.799267] Call Trace:
[37315.828515] nvme_update_ns_info+0x1ac/0x250 [nvme_core]
[37315.892075] nvme_validate_or_alloc_ns+0x2ff/0xa00 [nvme_core]
[37315.961871] ? __blk_mq_free_request+0x6b/0x90
[37316.015021] nvme_scan_work+0x151/0x240 [nvme_core]
[37316.073371] process_one_work+0x1a7/0x360
[37316.121318] ? create_worker+0x1a0/0x1a0
[37316.168227] worker_thread+0x30/0x390
[37316.212024] ? create_worker+0x1a0/0x1a0
[37316.258939] kthread+0x10a/0x120
[37316.297557] ? set_kthread_struct+0x50/0x50
[37316.347590] ret_from_fork+0x35/0x40
[37316.390360] Modules linked in: nvme_rdma nvme_tcp(X) nvme_fabrics nvme_core netconsole iscsi_tcp libiscsi_tcp dm_queue_length dm_service_time nf_conntrack_netlink br_netfilter bridge stp llc overlay nft_chain_nat ipt_MASQUERADE nf_nat xt_addrtype xt_CT nft_counter xt_state xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 xt_comment xt_multiport nft_compat nf_tables libcrc32c nfnetlink dm_multipath tg3 rpcrdma sunrpc rdma_ucm ib_srpt ib_isert iscsi_target_mod target_core_mod ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm intel_rapl_msr iTCO_wdt iTCO_vendor_support dcdbas intel_rapl_common sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel ipmi_ssif kvm irqbypass crct10dif_pclmul crc32_pclmul mlx5_ib ghash_clmulni_intel ib_uverbs rapl intel_cstate intel_uncore ib_core ipmi_si joydev mei_me pcspkr ipmi_devintf mei lpc_ich wmi ipmi_msghandler acpi_power_meter ext4 mbcache jbd2 sd_mod t10_pi sg mgag200 mlx5_core drm_kms_helper syscopyarea
[37316.390419] sysfillrect ahci sysimgblt fb_sys_fops libahci drm crc32c_intel libata mlxfw pci_hyperv_intf tls i2c_algo_bit psample dm_mirror dm_region_hash dm_log dm_mod fuse [last unloaded: nvme_core]
[37317.645908] CR2: 0000000000000050

Fixes: e7d65803e2bb ("nvme-multipath: revalidate paths during rescan")
Signed-off-by: Caleb Sander <csander@purestorage.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: set queue dma alignment to 3

NVMe spec requires all transports support dword aligned addresses, which
is already set in the namespace request_queue. Set the same limit in the
multipath device's request_queue as well.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: fix possible hang in live ns resize with ANA access

When we revalidate paths as part of ns size change (as of commit
e7d65803e2bb), it is possible that during the path revalidation, the
only paths that is IO capable (i.e. optimized/non-optimized) are the
ones that ns resize was not yet informed to the host, which will cause
inflight requests to be requeued (as we have available paths but none
are IO capable). These requests on the requeue list are waiting for
someone to resubmit them at some point.

The IO capable paths will eventually notify the ns resize change to the
host, but there is nothing that will kick the requeue list to resubmit
the queued requests.

Fix this by always kicking the requeue list, and if no IO capable path
exists, these requests will be queued again.

A typical log that indicates that IOs are requeued:
--
nvme nvme1: creating 4 I/O queues.
nvme nvme1: new ctrl: "testnqn1"
nvme nvme2: creating 4 I/O queues.
nvme nvme2: mapped 4/0/0 default/read/poll queues.
nvme nvme2: new ctrl: NQN "testnqn1", addr 127.0.0.1:8009
nvme nvme1: rescanning namespaces.
nvme1n1: detected capacity change from 2097152 to 4194304
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
block nvme1n1: no usable path - requeuing I/O
nvme nvme2: rescanning namespaces.
--

Reported-by: Yogev Cohen <yogev@lightbitslabs.com>
Fixes: e7d65803e2bb ("nvme-multipath: revalidate paths during rescan")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Cc: <stable@vger.kernel.org> # v5.15+
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: wire up async polling for io passthrough commands

Store a cookie during submission, and use that to implement
completion-polling inside the ->uring_cmd_iopoll handler.
This handler makes use of existing bio poll facility.

Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Link: https://lore.kernel.org/r/20220823161443.49436-5-joshi.k@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: change the blk_queue_split calling convention

The double indirect bio leads to somewhat suboptimal code generation.
Instead return the (original or split) bio, and make sure the
request_queue arguments to the lower level helpers is passed after the
bio to avoid constant reshuffling of the argument passing registers.

Also give it and the helpers used to implement it more descriptive names.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220727162300.3089193-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: define compat_ioctl again to unbreak 32-bit userspace.

Commit 89b3d6e60550 ("nvme: simplify the compat ioctl handling") removed
the initialization of compat_ioctl from the nvme block_device_operations
structures.

Presumably the expectation was that 32-bit ioctls would be directed
through the regular handler but this is not the case: failing to assign
.compat_ioctl actually means that the compat case is disabled entirely,
and any attempt to submit nvme ioctls from 32-bit userspace fails
outright with -ENOTTY.

For example:

% smartctl -x /dev/nvme0n1
[...]
Read NVMe Identify Controller failed: NVME_IOCTL_ADMIN_CMD: Inappropriate ioctl for device

The blkdev_compat_ptr_ioctl helper can be used to direct compat calls
through the main ioctl handler and makes things work again.

Fixes: 89b3d6e60550 ("nvme: simplify the compat ioctl handling")
Signed-off-by: Nick Bowler <nbowler@draconx.ca>
Reviewed-by: Guixin Liu <kanie@linux.alibaba.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: refactor nvme_mpath_add_disk

Pass anagrpid as second argument. This is prep patch that allows reusing
this function for supporting unknown command sets.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move zone related fields to struct gendisk

Move the zone related fields that are currently stored in
struct request_queue to struct gendisk as these are part of the highlevel
block layer API and are only used for non-passthrough I/O that requires
the gendisk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220706070350.1703384-17-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove blk_cleanup_disk

blk_cleanup_disk is nothing but a trivial wrapper for put_disk now,
so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20220619060552.1850436-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: wire-up uring-cmd support for io-passthru on char-device.

Introduce handler for fops->uring_cmd(), implementing async passthru
on char device (/dev/ngX). The handler supports newly introduced
operation NVME_URING_CMD_IO. This operates on a new structure
nvme_uring_cmd, which is similar to struct nvme_passthru_cmd64 but
without the embedded 8b result field. This field is not needed since
uring-cmd allows to return additional result via big-CQE.

Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Anuj Gupta <anuj20.g@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220511054750.20432-5-joshi.k@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: fix hang when disk goes live over reconnect

nvme_mpath_init_identify() invoked from nvme_init_identify() fetches a
fresh ANA log from the ctrl. This is essential to have an up to date
path states for both existing namespaces and for those scan_work may
discover once the ctrl is up.

This happens in the following cases:
1) A new ctrl is being connected.
2) An existing ctrl is successfully reconnected.
3) An existing ctrl is being reset.

While in (1) ctrl->namespaces is empty, (2 & 3) may have namespaces, and
nvme_read_ana_log() may call nvme_update_ns_ana_state().

This result in a hang when the ANA state of an existing namespace changes
and makes the disk live: nvme_mpath_set_live() issues IO to the namespace
through the ctrl, which does NOT have IO queues yet.

See sample hang below.

Solution:
- nvme_update_ns_ana_state() to call set_live only if ctrl is live
- nvme_read_ana_log() call from nvme_mpath_init_identify()
therefore only fetches and parses the ANA log;
any erros in this process will fail the ctrl setup as appropriate;
- a separate function nvme_mpath_update()
is called in nvme_start_ctrl();
this parses the ANA log without fetching it.
At this point the ctrl is live,
therefore, disks can be set live normally.

Sample failure:
nvme nvme0: starting error recovery
nvme nvme0: Reconnecting in 10 seconds...
block nvme0n6: no usable path - requeuing I/O
INFO: task kworker/u8:3:312 blocked for more than 122 seconds.
Tainted: G E 5.14.5-1.el7.elrepo.x86_64 #1
Workqueue: nvme-wq nvme_tcp_reconnect_ctrl_work [nvme_tcp]
Call Trace:
__schedule+0x2a2/0x7e0
schedule+0x4e/0xb0
io_schedule+0x16/0x40
wait_on_page_bit_common+0x15c/0x3e0
do_read_cache_page+0x1e0/0x410
read_cache_page+0x12/0x20
read_part_sector+0x46/0x100
read_lba+0x121/0x240
efi_partition+0x1d2/0x6a0
bdev_disk_changed.part.0+0x1df/0x430
bdev_disk_changed+0x18/0x20
blkdev_get_whole+0x77/0xe0
blkdev_get_by_dev+0xd2/0x3a0
__device_add_disk+0x1ed/0x310
device_add_disk+0x13/0x20
nvme_mpath_set_live+0x138/0x1b0 [nvme_core]
nvme_update_ns_ana_state+0x2b/0x30 [nvme_core]
nvme_update_ana_state+0xca/0xe0 [nvme_core]
nvme_parse_ana_log+0xac/0x170 [nvme_core]
nvme_read_ana_log+0x7d/0xe0 [nvme_core]
nvme_mpath_init_identify+0x105/0x150 [nvme_core]
nvme_init_identify+0x2df/0x4d0 [nvme_core]
nvme_init_ctrl_finish+0x8d/0x3b0 [nvme_core]
nvme_tcp_setup_ctrl+0x337/0x390 [nvme_tcp]
nvme_tcp_reconnect_ctrl_work+0x24/0x40 [nvme_tcp]
process_one_work+0x1bd/0x360
worker_thread+0x50/0x3d0

Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: allow duplicate NSIDs for private namespaces

A NVMe subsystem with multiple controller can have private namespaces
that use the same NSID under some conditions:

"If Namespace Management, ANA Reporting, or NVM Sets are supported, the
NSIDs shall be unique within the NVM subsystem. If the Namespace
Management, ANA Reporting, and NVM Sets are not supported, then NSIDs:
a) for shared namespace shall be unique; and
b) for private namespace are not required to be unique."

Reference: Section 6.1.6 NSID and Namespace Usage; NVM Express 1.4c spec.

Make sure this specific setup is supported in Linux.

Fixes: 9ad1927a3bc2 ("nvme: always search for namespace head")
Signed-off-by: Sungup Moon <sungup.moon@samsung.com>
[hch: refactored and fixed the controller vs subsystem based naming
conflict]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

nvme: cleanup how disk->disk_name is assigned

They way how assigning the disk name and commenting on why it is done
is split over core.c and multipath.c seems to be rather confusing.

Now that ns_head->disk always exists we can do all the work in core.c
and have a single big comment explaining the issues.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

nvme-multipath: call bio_io_error in nvme_ns_head_submit_bio

Use bio_io_error() here since bio_io_error does the same thing.

Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: use vmalloc for ANA log buffer

The ANA log buffer can get really large, as it depends on the
controller configuration. So to avoid an out-of-memory issue
during scanning use kvmalloc() instead of the kmalloc().

Signed-off-by: Hannes Reinecke <hare@suse.de>
Tested-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

block: fix surprise removal for drivers calling blk_set_queue_dying

Various block drivers call blk_set_queue_dying to mark a disk as dead due
to surprise removal events, but since commit 8e141f9eb803 that doesn't
work given that the GD_DEAD flag needs to be set to stop I/O.

Replace the driver calls to blk_set_queue_dying with a new (and properly
documented) blk_mark_disk_dead API, and fold blk_set_queue_dying into the
only remaining caller.

Fixes: 8e141f9eb803 ("block: drain file system I/O on del_gendisk")
Reported-by: Markus Blöchl <markus.bloechl@ipetronik.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Link: https://lore.kernel.org/r/20220217075231.1140-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: add 'iopolicy' module parameter

While the 'iopolicy' sysfs attribute can be set at runtime, most
storage arrays prefer to use the 'round-robin' iopolicy per default.
We can use udev rules to set this, but is getting rather unwieldy
for rebranded arrays as we would have to update the udev rules
anytime a new array shows up, leading to the same mess we currently
have in multipathd for configuring the RDAC arrays.

Hence this patch adds a module parameter 'iopolicy' to allow the
admin to switch the default, and to do away with the need for a
udev rule here.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: set ana_log_size to 0 after free ana_log_buf

Set ana_log_size to 0 when ana_log_buf is freed to make sure
nvme_mpath_init_identify will do the right thing when retrying
after an earlier failure.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: use flex_array_size and struct_size

In an effort to avoid open-coded arithmetic in the kernel [1], use the
flex_array_size() and struct_size() helpers instead of an open-coded
calculation.

[1] https://github.com/KSPP/linux/issues/160

Signed-off-by: Len Baker <len.baker@gmx.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: drop scan_lock and always kick requeue list when removing namespaces

When reading the partition table on initial scan hits an I/O error the
I/O will hang with the scan_mutex held:

[<0>] do_read_cache_page+0x49b/0x790
[<0>] read_part_sector+0x39/0xe0
[<0>] read_lba+0xf9/0x1d0
[<0>] efi_partition+0xf1/0x7f0
[<0>] bdev_disk_changed+0x1ee/0x550
[<0>] blkdev_get_whole+0x81/0x90
[<0>] blkdev_get_by_dev+0x128/0x2e0
[<0>] device_add_disk+0x377/0x3c0
[<0>] nvme_mpath_set_live+0x130/0x1b0 [nvme_core]
[<0>] nvme_mpath_add_disk+0x150/0x160 [nvme_core]
[<0>] nvme_alloc_ns+0x417/0x950 [nvme_core]
[<0>] nvme_validate_or_alloc_ns+0xe9/0x1e0 [nvme_core]
[<0>] nvme_scan_work+0x168/0x310 [nvme_core]
[<0>] process_one_work+0x231/0x420

and trying to delete the controller will deadlock as it tries to grab
the scan mutex:

[<0>] nvme_mpath_clear_ctrl_paths+0x25/0x80 [nvme_core]
[<0>] nvme_remove_namespaces+0x31/0xf0 [nvme_core]
[<0>] nvme_do_delete_ctrl+0x4b/0x80 [nvme_core]

As we're now properly ordering the namespace list there is no need to
hold the scan_mutex in nvme_mpath_clear_ctrl_paths() anymore.
And we always need to kick the requeue list as the path will be marked
as unusable and I/O will be requeued _without_ a current path.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: add error handling support for add_disk()

We never checked for errors on add_disk() as this function
returned void. Now that this is fixed, use the shiny new
error handling.

Since we now can tell for sure when a disk was added, move
setting the bit NVME_NSHEAD_DISK_LIVE only when we did
add the disk successfully.

Nothing to do here as the cleanup is done elsewhere. We take
care and use test_and_set_bit() because it is protects against
two nvme paths simultaneously calling device_add_disk() on the
same namespace head.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: generate uevent once a multipath namespace is operational again

When fast_io_fail_tmo is set I/O will be aborted while recovery is
still ongoing. This causes MD to set the namespace to failed, and
no futher I/O will be submitted to that namespace.

However, once the recovery succeeds and the namespace becomes
operational again the NVMe subsystem doesn't send a notification,
so MD cannot automatically reinstate operation and requires
manual interaction.

This patch will send a KOBJ_CHANGE uevent per multipathed namespace
once the underlying controller transitions to LIVE, allowing an automatic
MD reassembly with these udev rules:

/etc/udev/rules.d/65-md-auto-re-add.rules:
SUBSYSTEM!="block", GOTO="md_end"

ACTION!="change", GOTO="md_end"
ENV{ID_FS_TYPE}!="linux_raid_member", GOTO="md_end"
PROGRAM="/sbin/md_raid_auto_readd.sh $devnode"
LABEL="md_end"

/sbin/md_raid_auto_readd.sh:

MDADM=/sbin/mdadm
DEVNAME=$1

export $(${MDADM} --examine --export ${DEVNAME})

if [ -z "${MD_UUID}" ]; then
exit 1
fi

UUID_LINK=$(readlink /dev/disk/by-id/md-uuid-${MD_UUID})
MD_DEVNAME=${UUID_LINK##*/}
export $(${MDADM} --detail --export /dev/${MD_DEVNAME})
if [ -z "${MD_METADATA}" ] ; then
exit 1
fi
if [ $(cat /sys/block/${MD_DEVNAME}/md/degraded) != 1 ]; then
echo "${MD_DEVNAME}: array not degraded, nothing to do"
exit 0
fi
MD_STATE=$(cat /sys/block/${MD_DEVNAME}/md/array_state)
if [ ${MD_STATE} != "clean" ] ; then
echo "${MD_DEVNAME}: array state ${MD_STATE}, cannot re-add"
exit 1
fi
MD_VARNAME="MD_DEVICE_dev_${DEVNAME##*/}_ROLE"
if [ ${!MD_VARNAME} = "spare" ] ; then
${MDADM} --manage /dev/${MD_DEVNAME} --re-add ${DEVNAME}
fi

Changes to v2:
- Add udev rules example to description
Changes to v1:
- use disk_uevent() as suggested by hch

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: enable polled I/O

Set the poll queue flag to enable polling, given that the multipath
node just dispatches the bios to a lower queue.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-17-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: switch polling to be bio based

Replace the blk_poll interface that requires the caller to keep a queue
and cookie from the submissions with polling based on the bio.

Polling for the bio itself leads to a few advantages:

- the cookie construction can made entirely private in blk-mq.c
- the caller does not need to remember the request_queue and cookie
separately and thus sidesteps their lifetime issues
- keeping the device and the cookie inside the bio allows to trivially
support polling BIOs remapping by stacking drivers
- a lot of code to propagate the cookie back up the submission path can
be removed entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-15-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: fix per-namespace chardev deletion

Decrease reference count of chardevice during char device deletion in
order to fix a memory leak. Add a release callabck for the device
associated chardev and move ida_simple_remove into the release function.

Fixes: 2637baed7801 ("nvme: introduce generic per-namespace chardev")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Suggested-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Adam Manzanares <a.manzanares@samsung.com>
Reviewed-by: Javier González <javier@javigon.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: fix ANA state updates when a namespace is not present

nvme_update_ana_state() has a deficiency that results in a failure to
properly update the ana state for a namespace in the following case:

NSIDs in ctrl->namespaces: 1, 3, 4
NSIDs in desc->nsids: 1, 2, 3, 4

Loop iteration 0:
ns index = 0, n = 0, ns->head->ns_id = 1, nsid = 1, MATCH.
Loop iteration 1:
ns index = 1, n = 1, ns->head->ns_id = 3, nsid = 2, NO MATCH.
Loop iteration 2:
ns index = 2, n = 2, ns->head->ns_id = 4, nsid = 4, MATCH.

Where the update to the ANA state of NSID 3 is missed. To fix this
increment n and retry the update with the same ns when ns->head->ns_id is
higher than nsid,

Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

nvme-multipath: revalidate paths during rescan

When triggering a rescan due to a namespace resize we will be
receiving AENs on every controller, triggering a rescan of all
attached namespaces. If multipath is active only the current path and
the ns_head disk will be updated, the other paths will still refer to
the old size until AENs for the remaining controllers are received.

If I/O comes in before that it might be routed to one of the old
paths, triggering an I/O failure with 'access beyond end of device'.
With this patch the old paths are skipped from multipath path
selection until the controller serving these paths has been rescanned.

Signed-off-by: Hannes Reinecke <hare@suse.de>
[dwagner: - introduce NVME_NS_READY flag instead of NVME_NS_INVALIDATE
- use 'revalidate' instead of 'invalidate' which
follows the zoned device code path.
- clear NVME_NS_READY before clearing current_path]
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: set QUEUE_FLAG_NOWAIT

The nvme multipathing code just dispatches bios to one of the blk-mq
based paths and never blocks on its own, so set QUEUE_FLAG_NOWAIT
to support REQ_NOWAIT bios.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

nvme: replace the GENHD_FL_UP check in nvme_mpath_shutdown_disk

Use the nvme-internal NVME_NSHEAD_DISK_LIVE flag instead of abusing
the block layer state.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210809064028.1198327-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: fix refcounting imbalance when all paths are down

When the last path to a ns_head drops the current code
removes the ns_head from the subsystem list, but will only
delete the disk itself if the last reference to the ns_head
drops. This is causing an refcounting imbalance eg when
applications have a reference to the disk, as then they'll
never get notified that the disk is in fact dead.
This patch moves the call 'del_gendisk' into nvme_mpath_check_last_path(),
ensuring that the disk can be properly removed and applications get the
appropriate notifications.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: remove superfluous bio_set_dev in nvme_requeue_work

Commit ce86dad222e9 ("nvme-multipath: reset bdev to ns head when
failover") moved the reset code where the bio is added to the
requeue_list for the failover path. But it left the original
bio_set_dev in nvme_requeue_work.

There is a second path to nvme_requee_work. It is via
nvme_ns_head_submit_bio. Though we don't have to set bio->bi_bdev for
this path either, as it points to the correct bdev already.

Let's remove the bio_set_dev. It's updating the bio->bi_bdev with the
same pointer and thus it's unnecessary.

Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: verify MNAN value if ANA is enabled

The controller is required to have a non-zero MNAN value if it supports
ANA:

If the controller supports Asymmetric Namespace Access Reporting, then
this field shall be set to a non-zero value that is less than or equal
to the NN value.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: split nvme_report_zones

Split multipath support out of nvme_report_zones into a separate helper
and simplify the non-multipath version as a result.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

nvme-multipath: convert to blk_alloc_disk/blk_cleanup_disk

Convert the nvme-multipath driver to use the blk_alloc_disk and
blk_cleanup_disk helpers to simplify gendisk and request_queue
allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-19-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: automatically enable GENHD_FL_EXT_DEVT

Automatically set the GENHD_FL_EXT_DEVT flag for all disks allocated
without an explicit number of minors. This is what all new block
drivers should do, so make sure it is the default without boilerplate
code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210521055116.1053587-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvmet: use new ana_log_size instead the old one

The new ana_log_size should be used instead of the old one.
Or kernel NULL pointer dereference will happen like below:

[ 38.957849][ T69] BUG: kernel NULL pointer dereference, address: 000000000000003c
[ 38.975550][ T69] #PF: supervisor write access in kernel mode
[ 38.975955][ T69] #PF: error_code(0x0002) - not-present page
[ 38.976905][ T69] PGD 0 P4D 0
[ 38.979388][ T69] Oops: 0002 [#1] SMP NOPTI
[ 38.980488][ T69] CPU: 0 PID: 69 Comm: kworker/0:2 Not tainted 5.12.0+ #54
[ 38.981254][ T69] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 38.982502][ T69] Workqueue: events nvme_loop_execute_work
[ 38.985219][ T69] RIP: 0010:memcpy_orig+0x68/0x10f
[ 38.986203][ T69] Code: 83 c2 20 eb 44 48 01 d6 48 01 d7 48 83 ea 20 0f 1f 00 48 83 ea 20 4c 8b 46 f8 4c 8b 4e f0 4c 8b 56 e8 4c 8b 5e e0 48 8d 76 e0 <4c> 89 47 f8 4c 89 4f f0 4c 89 57 e8 4c 89 5f e0 48 8d 7f e0 73 d2
[ 38.987677][ T69] RSP: 0018:ffffc900001b7d48 EFLAGS: 00000287
[ 38.987996][ T69] RAX: 0000000000000020 RBX: 0000000000000024 RCX: 0000000000000010
[ 38.988327][ T69] RDX: ffffffffffffffe4 RSI: ffff8881084bc004 RDI: 0000000000000044
[ 38.988620][ T69] RBP: 0000000000000024 R08: 0000000100000000 R09: 0000000000000000
[ 38.988991][ T69] R10: 0000000100000000 R11: 0000000000000001 R12: 0000000000000024
[ 38.989289][ T69] R13: ffff8881084bc000 R14: 0000000000000000 R15: 0000000000000024
[ 38.989845][ T69] FS: 0000000000000000(0000) GS:ffff888237c00000(0000) knlGS:0000000000000000
[ 38.990234][ T69] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 38.990490][ T69] CR2: 000000000000003c CR3: 00000001085b2000 CR4: 00000000000006f0
[ 38.991105][ T69] Call Trace:
[ 38.994157][ T69] sg_copy_buffer+0xb8/0xf0
[ 38.995357][ T69] nvmet_copy_to_sgl+0x48/0x6d
[ 38.995565][ T69] nvmet_execute_get_log_page_ana+0xd4/0x1cb
[ 38.995792][ T69] nvmet_execute_get_log_page+0xc9/0x146
[ 38.995992][ T69] nvme_loop_execute_work+0x3e/0x44
[ 38.996181][ T69] process_one_work+0x1c3/0x3c0
[ 38.996393][ T69] worker_thread+0x44/0x3d0
[ 38.996600][ T69] ? cancel_delayed_work+0x90/0x90
[ 38.996804][ T69] kthread+0xf7/0x130
[ 38.996961][ T69] ? kthread_create_worker_on_cpu+0x70/0x70
[ 38.997171][ T69] ret_from_fork+0x22/0x30
[ 38.997705][ T69] Modules linked in:
[ 38.998741][ T69] CR2: 000000000000003c
[ 39.000104][ T69] ---[ end trace e719927b609d0fa0 ]---

Fixes: 5e1f689913a4 ("nvme-multipath: fix double initialization of ANA state")
Signed-off-by: Hou Pu <houpu.main@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: fix double initialization of ANA state

nvme_init_identify and thus nvme_mpath_init can be called multiple
times and thus must not overwrite potentially initialized or in-use
fields. Split out a helper for the basic initialization when the
controller is initialized and make sure the init_identify path does
not blindly change in-use data structures.

Fixes: 0d0b660f214d ("nvme: add ANA support")
Reported-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Hannes Reinecke <hare@suse.de>

nvme-multipath: reset bdev to ns head when failover

When a request finally completes in end_io() after it has failed over,
the bdev pointer can be stale and thus the system can crash. Set the
bdev back to ns head, so the request is map to an active path when
resubmitted.

Signed-off-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: introduce generic per-namespace chardev

Userspace has not been allowed to I/O to device that's failed to
be initialized. This patch introduces generic per-namespace character
device to allow userspace to I/O regardless the block device is there or
not.

The chardev naming convention will similar to the existing blkdev naming,
using a ng prefix instead of nvme, i.e.

- /dev/ngXnY

It also supports multipath which means it will not expose chardev for the
hidden namespace blkdevs (e.g., nvmeXcYnZ). If /dev/ngXnY is created for
a ns_head, then I/O request will be routed to a specific controller
selected by the iopolicy of the subsystem.

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
Signed-off-by: Javier González <javier.gonz@samsung.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Tested-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: move nvme_ns_head_ops to multipath.c

Move the multipath block_device_operations to multipath.c, where they
belong.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Javier González <javier.gonz@samsung.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>

nvme: cleanup setting the disk name

Return false from nvme_set_disk_name and let the caller set the
non-multipath name instead of duplicating the naming information in two
places. Also remove the pointless local variables for the disk name
and flags and the not needed ctrl argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Javier González <javier.gonz@samsung.com>

nvme-multipath: remove single trailing whitespace

There is a single trailing whitespace in multipath.c.
Since this is just a single whitespace, the chances of this affecting
backports to stable should be quite low, so let's just remove it.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: retrigger ANA log update if group descriptor isn't found

If ANA is enabled but no ANA group descriptor is found when creating
a new namespace the ANA log is most likely out of date, so trigger
a re-read. The namespace will be tagged with the NS_ANA_PENDING flag
to exclude it from path selection until the ANA log has been re-read.

Fixes: 32acab3181c7 ("nvme: implement multipath access to nvme subsystems")
Reported-by: Martin George <marting@netapp.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: use sysfs_emit instead of sprintf

sysfs_emit is the recommended API to use for formatting strings to be
returned to user space. It is equivalent to scnprintf and aware of the
PAGE_SIZE buffer size.

Suggested-by: Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: set nr_zones for zoned namespaces

The bio based drivers only require the request_queue's nr_zones is set,
so set this field in the head if the namespace path is zoned.

Fixes: 240e6ee272c07 ("nvme: support for zoned namespaces")
Reported-by: Minwoo Im <minwoo.im.dev@gmail.com>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: use bio_set_dev to assign ->bi_bdev

Always use the bio_set_dev helper to assign ->bi_bdev to make sure
other state related to the device is uptodate.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: store a block_device pointer in struct bio

Replace the gendisk pointer in struct bio with a pointer to the newly
improved struct block device. From that the gendisk can be trivially
accessed with an extra indirection, but it also allows to directly
look up all information related to partition remapping.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: Early exit if no path is available

nvme_round_robin_path() should test if the return ns pointer is valid.
nvme_next_ns() will return a NULL pointer if there is no path left.

Fixes: 75c10e732724 ("nvme-multipath: round-robin I/O policy")
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

block: remove the request_queue argument to the block_bio_remap tracepoint

The request_queue can trivially be derived from the bio.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-fabrics: reject I/O to offline device

Commands get stuck while Host NVMe-oF controller is in reconnect state.
The controller enters into reconnect state when it loses connection with
the target. It tries to reconnect every 10 seconds (default) until
a successful reconnect or until the reconnect time-out is reached.
The default reconnect time out is 10 minutes.

Applications are expecting commands to complete with success or error
within a certain timeout (30 seconds by default). The NVMe host is
enforcing that timeout while it is connected, but during reconnect the
timeout is not enforced and commands may get stuck for a long period or
even forever.

To fix this long delay due to the default timeout, introduce new
"fast_io_fail_tmo" session parameter. The timeout is measured in seconds
from the controller reconnect and any command beyond that timeout is
rejected. The new parameter value may be passed during 'connect'.
The default value of -1 means no timeout (similar to current behavior).

Signed-off-by: Victor Gladkov <victor.gladkov@kioxia.com>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chao Leng <lengchao@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

bdi: replace BDI_CAP_STABLE_WRITES with a queue and a sb flag

The BDI_CAP_STABLE_WRITES is one of the few bits of information in the
backing_dev_info shared between the block drivers and the writeback code.
To help untangling the dependency replace it with a queue flag and a
superblock flag derived from it. This also helps with the case of e.g.
a file system requiring stable writes due to its own checksumming, but
not forcing it on other users of the block device like the swap code.

One downside is that we an't support the stable_pages_required bdi
attribute in sysfs anymore. It is replaced with a queue attribute which
also is writable for easier testing.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: refactor command completion

Lift all the code to decide the dispostition of a completed command
from nvme_complete_rq and nvme_failover_req into a new helper, which
returns an emum of the potential actions. nvme_complete_rq then
just switches on those and calls the proper helper for the action.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: multipath: round-robin: eliminate "fallback" variable

If we find an optimized path, we quit the loop immediately. Thus we can use
just one variable for the next path, slighly simplifying the code.

Signed-off-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: multipath: round-robin: fix single non-optimized path case

If there's only one usable, non-optimized path, nvme_round_robin_path()
returns NULL, which is wrong. Fix it by falling back to "old", like in
the single optimized path case. Also, if the active path isn't changed,
there's no need to re-assign the pointer.

Fixes: 3f6e3246db0e ("nvme-multipath: fix logic for non-optimized paths")
Signed-off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Martin George <marting@netapp.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: do not fall back to __nvme_find_path() for non-optimized paths

When nvme_round_robin_path() finds a valid namespace we should be using it;
falling back to __nvme_find_path() for non-optimized paths will cause the
result from nvme_round_robin_path() to be ignored for non-optimized paths.

Fixes: 75c10e732724 ("nvme-multipath: round-robin I/O policy")
Signed-off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: fix logic for non-optimized paths

Handle the special case where we have exactly one optimized path,
which we should keep using in this case.

Fixes: 75c10e732724 ("nvme-multipath: round-robin I/O policy")
Signed off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: fix deadlock in disconnect during scan_work and/or ana_work

A deadlock happens in the following scenario with multipath:
1) scan_work(nvme0) detects a new nsid while nvme0
is an optimized path to it, path nvme1 happens to be
inaccessible.

2) Before scan_work is complete nvme0 disconnect is initiated
nvme_delete_ctrl_sync() sets nvme0 state to NVME_CTRL_DELETING

3) scan_work(1) attempts to submit IO,
but nvme_path_is_optimized() observes nvme0 is not LIVE.
Since nvme1 is a possible path IO is requeued and scan_work hangs.

--
Workqueue: nvme-wq nvme_scan_work [nvme_core]
kernel: Call Trace:
kernel: __schedule+0x2b9/0x6c0
kernel: schedule+0x42/0xb0
kernel: io_schedule+0x16/0x40
kernel: do_read_cache_page+0x438/0x830
kernel: read_cache_page+0x12/0x20
kernel: read_dev_sector+0x27/0xc0
kernel: read_lba+0xc1/0x220
kernel: efi_partition+0x1e6/0x708
kernel: check_partition+0x154/0x244
kernel: rescan_partitions+0xae/0x280
kernel: __blkdev_get+0x40f/0x560
kernel: blkdev_get+0x3d/0x140
kernel: __device_add_disk+0x388/0x480
kernel: device_add_disk+0x13/0x20
kernel: nvme_mpath_set_live+0x119/0x140 [nvme_core]
kernel: nvme_update_ns_ana_state+0x5c/0x60 [nvme_core]
kernel: nvme_set_ns_ana_state+0x1e/0x30 [nvme_core]
kernel: nvme_parse_ana_log+0xa1/0x180 [nvme_core]
kernel: nvme_mpath_add_disk+0x47/0x90 [nvme_core]
kernel: nvme_validate_ns+0x396/0x940 [nvme_core]
kernel: nvme_scan_work+0x24f/0x380 [nvme_core]
kernel: process_one_work+0x1db/0x380
kernel: worker_thread+0x249/0x400
kernel: kthread+0x104/0x140
--

4) Delete also hangs in flush_work(ctrl->scan_work)
from nvme_remove_namespaces().

Similiarly a deadlock with ana_work may happen: if ana_work has started
and calls nvme_mpath_set_live and device_add_disk, it will
trigger I/O. When we trigger disconnect I/O will block because
our accessible (optimized) path is disconnecting, but the alternate
path is inaccessible, so I/O blocks. Then disconnect tries to flush
the ana_work and hangs.

[ 605.550896] Workqueue: nvme-wq nvme_ana_work [nvme_core]
[ 605.552087] Call Trace:
[ 605.552683] __schedule+0x2b9/0x6c0
[ 605.553507] schedule+0x42/0xb0
[ 605.554201] io_schedule+0x16/0x40
[ 605.555012] do_read_cache_page+0x438/0x830
[ 605.556925] read_cache_page+0x12/0x20
[ 605.557757] read_dev_sector+0x27/0xc0
[ 605.558587] amiga_partition+0x4d/0x4c5
[ 605.561278] check_partition+0x154/0x244
[ 605.562138] rescan_partitions+0xae/0x280
[ 605.563076] __blkdev_get+0x40f/0x560
[ 605.563830] blkdev_get+0x3d/0x140
[ 605.564500] __device_add_disk+0x388/0x480
[ 605.565316] device_add_disk+0x13/0x20
[ 605.566070] nvme_mpath_set_live+0x5e/0x130 [nvme_core]
[ 605.567114] nvme_update_ns_ana_state+0x2c/0x30 [nvme_core]
[ 605.568197] nvme_update_ana_state+0xca/0xe0 [nvme_core]
[ 605.569360] nvme_parse_ana_log+0xa1/0x180 [nvme_core]
[ 605.571385] nvme_read_ana_log+0x76/0x100 [nvme_core]
[ 605.572376] nvme_ana_work+0x15/0x20 [nvme_core]
[ 605.573330] process_one_work+0x1db/0x380
[ 605.574144] worker_thread+0x4d/0x400
[ 605.574896] kthread+0x104/0x140
[ 605.577205] ret_from_fork+0x35/0x40
[ 605.577955] INFO: task nvme:14044 blocked for more than 120 seconds.
[ 605.579239] Tainted: G OE 5.3.5-050305-generic #201910071830
[ 605.580712] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 605.582320] nvme D 0 14044 14043 0x00000000
[ 605.583424] Call Trace:
[ 605.583935] __schedule+0x2b9/0x6c0
[ 605.584625] schedule+0x42/0xb0
[ 605.585290] schedule_timeout+0x203/0x2f0
[ 605.588493] wait_for_completion+0xb1/0x120
[ 605.590066] __flush_work+0x123/0x1d0
[ 605.591758] __cancel_work_timer+0x10e/0x190
[ 605.593542] cancel_work_sync+0x10/0x20
[ 605.594347] nvme_mpath_stop+0x2f/0x40 [nvme_core]
[ 605.595328] nvme_stop_ctrl+0x12/0x50 [nvme_core]
[ 605.596262] nvme_do_delete_ctrl+0x3f/0x90 [nvme_core]
[ 605.597333] nvme_sysfs_delete+0x5c/0x70 [nvme_core]
[ 605.598320] dev_attr_store+0x17/0x30

Fix this by introducing a new state: NVME_CTRL_DELETE_NOIO, which will
indicate the phase of controller deletion where I/O cannot be allowed
to access the namespace. NVME_CTRL_DELETING still allows mpath I/O to
be issued to the bottom device, and only after we flush the ana_work
and scan_work (after nvme_stop_ctrl and nvme_prep_remove_namespaces)
we change the state to NVME_CTRL_DELETING_NOIO. Also we prevent ana_work
from re-firing by aborting early if we are not LIVE, so we should be safe
here.

In addition, change the transport drivers to follow the updated state
machine.

Fixes: 0d0b660f214d ("nvme: add ANA support")
Reported-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: support for multiple Command Sets Supported and Effects log pages

The Commands Supported and Effects log page was extended with a CSI
field that enables the host to query the log page for each command set
supported. Retrieve this log page for each command set that an attached
namespace supports, and save a pointer to that log in the namespace head.

Reviewed-by: Matias Bjørling <matias.bjorling@wdc.com>
Reviewed-by: Javier González <javier.gonz@samsung.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Keith Busch <keith.busch@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: fix a crash in nvme_mpath_add_disk

For private namespaces ns->head_disk is NULL, so add a NULL check
before updating the BDI capabilities.

Fixes: b2ce4d90690b ("nvme-multipath: set bdi capabilities once")
Reported-by: Avinash M N <Avinash.M.N@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>

block: remove direct_make_request

Now that submit_bio_noacct has a decent blk-mq fast path there is no
more need for this bypass.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: rename generic_make_request to submit_bio_noacct

generic_make_request has always been very confusingly misnamed, so rename
it to submit_bio_noacct to make it clear that it is submit_bio minus
accounting and a few checks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: move ->make_request_fn to struct block_device_operations

The make_request_fn is a little weird in that it sits directly in
struct request_queue instead of an operation vector. Replace it with
a block_device_operations method called submit_bio (which describes much
better what it does). Also remove the request_queue argument to it, as
the queue can be derived pretty trivially from the bio.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the request_queue argument from blk_queue_split

The queue can be trivially derived from the bio, so pass one less
argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: fix bogus request queue reference put

The mpath disk node takes a reference on the request mpath
request queue when adding live path to the mpath gendisk.
However if we connected to an inaccessible path device_add_disk
is not called, so if we disconnect and remove the mpath gendisk
we endup putting an reference on the request queue that was
never taken [1].

Fix that to check if we ever added a live path (using
NVME_NS_HEAD_HAS_DISK flag) and if not, clear the disk->queue
reference.

[1]:
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 1372 at lib/refcount.c:28 refcount_warn_saturate+0xa6/0xf0
CPU: 1 PID: 1372 Comm: nvme Tainted: G O 5.7.0-rc2+ #3
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1 04/01/2014
RIP: 0010:refcount_warn_saturate+0xa6/0xf0
RSP: 0018:ffffb29e8053bdc0 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff8b7a2f4fc060 RCX: 0000000000000007
RDX: 0000000000000007 RSI: 0000000000000092 RDI: ffff8b7a3ec99980
RBP: ffff8b7a2f4fc000 R08: 00000000000002e1 R09: 0000000000000004
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: fffffffffffffff2 R14: ffffb29e8053bf08 R15: ffff8b7a320e2da0
FS: 00007f135d4ca800(0000) GS:ffff8b7a3ec80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005651178c0c30 CR3: 000000003b650005 CR4: 0000000000360ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
disk_release+0xa2/0xc0
device_release+0x28/0x80
kobject_put+0xa5/0x1b0
nvme_put_ns_head+0x26/0x70 [nvme_core]
nvme_put_ns+0x30/0x60 [nvme_core]
nvme_remove_namespaces+0x9b/0xe0 [nvme_core]
nvme_do_delete_ctrl+0x43/0x5c [nvme_core]
nvme_sysfs_delete.cold+0x8/0xd [nvme_core]
kernfs_fop_write+0xc1/0x1a0
vfs_write+0xb6/0x1a0
ksys_write+0x5f/0xe0
do_syscall_64+0x52/0x1a0
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported-by: Anton Eidelman <anton@lightbitslabs.com>
Tested-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: fix deadlock due to head->lock

In the following scenario scan_work and ana_work will deadlock:

When scan_work calls nvme_mpath_add_disk() this holds ana_lock
and invokes nvme_parse_ana_log(), which may issue IO
in device_add_disk() and hang waiting for an accessible path.

While nvme_mpath_set_live() only called when nvme_state_is_live(),
a transition may cause NVME_SC_ANA_TRANSITION and requeue the IO.

Since nvme_mpath_set_live() holds ns->head->lock, an ana_work on
ANY ctrl will not be able to complete nvme_mpath_set_live()
on the same ns->head, which is required in order to update
the new accessible path and remove NVME_NS_ANA_PENDING..
Therefore IO never completes: deadlock [1].

Fix:
Move device_add_disk out of the head->lock and protect it with an
atomic test_and_set for a new NVME_NS_HEAD_HAS_DISK bit.

[1]:
kernel: INFO: task kworker/u8:2:160 blocked for more than 120 seconds.
kernel: Tainted: G OE 5.3.5-050305-generic #201910071830
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: kworker/u8:2 D 0 160 2 0x80004000
kernel: Workqueue: nvme-wq nvme_ana_work [nvme_core]
kernel: Call Trace:
kernel: __schedule+0x2b9/0x6c0
kernel: schedule+0x42/0xb0
kernel: schedule_preempt_disabled+0xe/0x10
kernel: __mutex_lock.isra.0+0x182/0x4f0
kernel: __mutex_lock_slowpath+0x13/0x20
kernel: mutex_lock+0x2e/0x40
kernel: nvme_update_ns_ana_state+0x22/0x60 [nvme_core]
kernel: nvme_update_ana_state+0xca/0xe0 [nvme_core]
kernel: nvme_parse_ana_log+0xa1/0x180 [nvme_core]
kernel: nvme_read_ana_log+0x76/0x100 [nvme_core]
kernel: nvme_ana_work+0x15/0x20 [nvme_core]
kernel: process_one_work+0x1db/0x380
kernel: worker_thread+0x4d/0x400
kernel: kthread+0x104/0x140
kernel: ret_from_fork+0x35/0x40
kernel: INFO: task kworker/u8:4:439 blocked for more than 120 seconds.
kernel: Tainted: G OE 5.3.5-050305-generic #201910071830
kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kernel: kworker/u8:4 D 0 439 2 0x80004000
kernel: Workqueue: nvme-wq nvme_scan_work [nvme_core]
kernel: Call Trace:
kernel: __schedule+0x2b9/0x6c0
kernel: schedule+0x42/0xb0
kernel: io_schedule+0x16/0x40
kernel: do_read_cache_page+0x438/0x830
kernel: read_cache_page+0x12/0x20
kernel: read_dev_sector+0x27/0xc0
kernel: read_lba+0xc1/0x220
kernel: efi_partition+0x1e6/0x708
kernel: check_partition+0x154/0x244
kernel: rescan_partitions+0xae/0x280
kernel: __blkdev_get+0x40f/0x560
kernel: blkdev_get+0x3d/0x140
kernel: __device_add_disk+0x388/0x480
kernel: device_add_disk+0x13/0x20
kernel: nvme_mpath_set_live+0x119/0x140 [nvme_core]
kernel: nvme_update_ns_ana_state+0x5c/0x60 [nvme_core]
kernel: nvme_mpath_add_disk+0xbe/0x100 [nvme_core]
kernel: nvme_validate_ns+0x396/0x940 [nvme_core]
kernel: nvme_scan_work+0x256/0x390 [nvme_core]
kernel: process_one_work+0x1db/0x380
kernel: worker_thread+0x4d/0x400
kernel: kthread+0x104/0x140
kernel: ret_from_fork+0x35/0x40

Fixes: 0d0b660f214d ("nvme: add ANA support")
Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: don't protect ns mutation with ns->head->lock

Right now ns->head->lock is protecting namespace mutation
which is wrong and unneeded. Move it to only protect
against head mutations. While we're at it, remove unnecessary
ns->head reference as we already have head pointer.

The problem with this is that the head->lock spans
mpath disk node I/O that may block under some conditions (if
for example the controller is disconnecting or the path
became inaccessible), The locking scheme does not allow any
other path to enable itself, preventing blocked I/O to complete
and forward-progress from there.

This is a preparation patch for the fix in a subsequent patch
where the disk I/O will also be done outside the head->lock.

Fixes: 0d0b660f214d ("nvme: add ANA support")
Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: fix deadlock between ana_work and scan_work

When scan_work calls nvme_mpath_add_disk() this holds ana_lock
and invokes nvme_parse_ana_log(), which may issue IO
in device_add_disk() and hang waiting for an accessible path.
While nvme_mpath_set_live() only called when nvme_state_is_live(),
a transition may cause NVME_SC_ANA_TRANSITION and requeue the IO.

In order to recover and complete the IO ana_work on the same ctrl
should be able to update the path state and remove NVME_NS_ANA_PENDING.

The deadlock occurs because scan_work keeps holding ana_lock,
so ana_work hangs [1].

Fix:
Now nvme_mpath_add_disk() uses nvme_parse_ana_log() to obtain a copy
of the ANA group desc, and then calls nvme_update_ns_ana_state() without
holding ana_lock.

[1]:
kernel: Workqueue: nvme-wq nvme_scan_work [nvme_core]
kernel: Call Trace:
kernel: __schedule+0x2b9/0x6c0
kernel: schedule+0x42/0xb0
kernel: io_schedule+0x16/0x40
kernel: do_read_cache_page+0x438/0x830
kernel: read_cache_page+0x12/0x20
kernel: read_dev_sector+0x27/0xc0
kernel: read_lba+0xc1/0x220
kernel: efi_partition+0x1e6/0x708
kernel: check_partition+0x154/0x244
kernel: rescan_partitions+0xae/0x280
kernel: __blkdev_get+0x40f/0x560
kernel: blkdev_get+0x3d/0x140
kernel: __device_add_disk+0x388/0x480
kernel: device_add_disk+0x13/0x20
kernel: nvme_mpath_set_live+0x119/0x140 [nvme_core]
kernel: nvme_update_ns_ana_state+0x5c/0x60 [nvme_core]
kernel: nvme_set_ns_ana_state+0x1e/0x30 [nvme_core]
kernel: nvme_parse_ana_log+0xa1/0x180 [nvme_core]
kernel: nvme_mpath_add_disk+0x47/0x90 [nvme_core]
kernel: nvme_validate_ns+0x396/0x940 [nvme_core]
kernel: nvme_scan_work+0x24f/0x380 [nvme_core]
kernel: process_one_work+0x1db/0x380
kernel: worker_thread+0x249/0x400
kernel: kthread+0x104/0x140

kernel: Workqueue: nvme-wq nvme_ana_work [nvme_core]
kernel: Call Trace:
kernel: __schedule+0x2b9/0x6c0
kernel: schedule+0x42/0xb0
kernel: schedule_preempt_disabled+0xe/0x10
kernel: __mutex_lock.isra.0+0x182/0x4f0
kernel: ? __switch_to_asm+0x34/0x70
kernel: ? select_task_rq_fair+0x1aa/0x5c0
kernel: ? kvm_sched_clock_read+0x11/0x20
kernel: ? sched_clock+0x9/0x10
kernel: __mutex_lock_slowpath+0x13/0x20
kernel: mutex_lock+0x2e/0x40
kernel: nvme_read_ana_log+0x3a/0x100 [nvme_core]
kernel: nvme_ana_work+0x15/0x20 [nvme_core]
kernel: process_one_work+0x1db/0x380
kernel: worker_thread+0x4d/0x400
kernel: kthread+0x104/0x140
kernel: ? process_one_work+0x380/0x380
kernel: ? kthread_park+0x80/0x80
kernel: ret_from_fork+0x35/0x40

Fixes: 0d0b660f214d ("nvme: add ANA support")
Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: define constants for identification values

Improve code readability by defining the specification's constants that
the driver is using when decoding identification payloads.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Bart van Assche <bvanassche@acm.org>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: stop using ->queuedata

nvme-multipath already uses the gendisk private data, not need to
also set up the request_queue queuedata and use it in one place only.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: set bdi capabilities once

The queues' backing device info capabilities don't change with each
namespace revalidation. Set it only when each path's request_queue
is initially added to a multipath queue.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: fix deadlock caused by ANA update wrong locking

The deadlock combines 4 flows in parallel:
- ns scanning (triggered from reconnect)
- request timeout
- ANA update (triggered from reconnect)
- I/O coming into the mpath device

(1) ns scanning triggers disk revalidation -> update disk info ->
freeze queue -> but blocked, due to (2)

(2) timeout handler reference the g_usage_counter - > but blocks in
the transport .timeout() handler, due to (3)

(3) the transport timeout handler (indirectly) calls nvme_stop_queue() ->
which takes the (down_read) namespaces_rwsem - > but blocks, due to (4)

(4) ANA update takes the (down_write) namespaces_rwsem -> calls
nvme_mpath_set_live() -> which synchronize the ns_head srcu
(see commit 504db087aacc) -> but blocks, due to (5)

(5) I/O came into nvme_mpath_make_request -> took srcu_read_lock ->
direct_make_request > blk_queue_enter -> but blocked, due to (1)

==> the request queue is under freeze -> deadlock.

The fix is making ANA update take a read lock as the namespaces list
is not manipulated, it is just the ns and ns->head that are being
updated (which is protected with the ns->head lock).

Fixes: 0d0b660f214dc ("nvme: add ANA support")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

block: simplify queue allocation

Current make_request based drivers use either blk_alloc_queue_node or
blk_alloc_queue to allocate a queue, and then set up the make_request_fn
function pointer and a few parameters using the blk_queue_make_request
helper. Simplify this by passing the make_request pointer to
blk_alloc_queue, and while at it merge the _node variant into the main
helper by always passing a node_id, and remove the superfluous gfp_mask
parameter. A lower-level __blk_alloc_queue is kept for the blk-mq case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: do not reset on unknown status

The nvme multipath error handling defaults to controller reset if the
error is unknown. There are, however, no existing nvme status codes that
indicate a reset should be used, and resetting causes unnecessary
disruption to the rest of IO.

Change nvme's error handling to first check if failover should happen.
If not, let the normal error handling take over rather than reset the
controller.

Based-on-a-patch-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Meneghini <johnm@netapp.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

nvme-multipath: Fix memory leak with ana_log_buf

kmemleak reports a memory leak with the ana_log_buf allocated by
nvme_mpath_init():

unreferenced object 0xffff888120e94000 (size 8208):
comm "nvme", pid 6884, jiffies 4295020435 (age 78786.312s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................
01 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000e2360188>] kmalloc_order+0x97/0xc0
[<0000000079b18dd4>] kmalloc_order_trace+0x24/0x100
[<00000000f50c0406>] __kmalloc+0x24c/0x2d0
[<00000000f31a10b9>] nvme_mpath_init+0x23c/0x2b0
[<000000005802589e>] nvme_init_identify+0x75f/0x1600
[<0000000058ef911b>] nvme_loop_configure_admin_queue+0x26d/0x280
[<00000000673774b9>] nvme_loop_create_ctrl+0x2a7/0x710
[<00000000f1c7a233>] nvmf_dev_write+0xc66/0x10b9
[<000000004199f8d0>] __vfs_write+0x50/0xa0
[<0000000065466fef>] vfs_write+0xf3/0x280
[<00000000b0db9a8b>] ksys_write+0xc6/0x160
[<0000000082156b91>] __x64_sys_write+0x43/0x50
[<00000000c34fbb6d>] do_syscall_64+0x77/0x2f0
[<00000000bbc574c9>] entry_SYSCALL_64_after_hwframe+0x49/0xbe

nvme_mpath_init() is called by nvme_init_identify() which is called in
multiple places (nvme_reset_work(), nvme_passthru_end(), etc). This
means nvme_mpath_init() may be called multiple times before
nvme_mpath_uninit() (which is only called on nvme_free_ctrl()).

When nvme_mpath_init() is called multiple times, it overwrites the
ana_log_buf pointer with a new allocation, thus leaking the previous
allocation.

To fix this, free ana_log_buf before allocating a new one.

Fixes: 0d0b660f214dc490 ("nvme: add ANA support")
Cc: <stable@vger.kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

nvme-multipath: fix crash in nvme_mpath_clear_ctrl_paths

nvme_mpath_clear_ctrl_paths() iterates through
the ctrl->namespaces list while holding ctrl->scan_lock.
This does not seem to be the correct way of protecting
from concurrent list modification.

Specifically, nvme_scan_work() sorts ctrl->namespaces
AFTER unlocking scan_lock.

This may result in the following (rare) crash in ctrl disconnect
during scan_work:

BUG: kernel NULL pointer dereference, address: 0000000000000050
Oops: 0000 [#1] SMP PTI
CPU: 0 PID: 3995 Comm: nvme 5.3.5-050305-generic
RIP: 0010:nvme_mpath_clear_current_path+0xe/0x90 [nvme_core]
...
Call Trace:
nvme_mpath_clear_ctrl_paths+0x3c/0x70 [nvme_core]
nvme_remove_namespaces+0x35/0xe0 [nvme_core]
nvme_do_delete_ctrl+0x47/0x90 [nvme_core]
nvme_sysfs_delete+0x49/0x60 [nvme_core]
dev_attr_store+0x17/0x30
sysfs_kf_write+0x3e/0x50
kernfs_fop_write+0x11e/0x1a0
__vfs_write+0x1b/0x40
vfs_write+0xb9/0x1a0
ksys_write+0x67/0xe0
__x64_sys_write+0x1a/0x20
do_syscall_64+0x5a/0x130
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f8d02bfb154

Fix:
After taking scan_lock in nvme_mpath_clear_ctrl_paths()
down_read(&ctrl->namespaces_rwsem) as well to make list traversal safe.
This will not cause deadlocks because taking scan_lock never happens
while holding the namespaces_rwsem.
Moreover, scan work downs namespaces_rwsem in the same order.

Alternative: sort ctrl->namespaces in nvme_scan_work()
while still holding the scan_lock.
This would leave nvme_mpath_clear_ctrl_paths() without correct protection
against ctrl->namespaces modification by anyone other than scan_work.

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>

nvme: Fix parsing of ANA log page

Check validity of offset into ANA log buffer before accessing
nvme_ana_group_desc. This check ensures the size of ANA log buffer >=
offset + sizeof(nvme_ana_group_desc)

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Prabhath Sajeepa <psajeepa@purestorage.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: introduce "Command Aborted By host" status code

Fix the status code of canceled requests initiated by the host according
to TP4028 (Status Code 0x371):
"Command Aborted By host: The command was aborted as a result of host
action (e.g., the host disconnected the Fabric connection)."

Also in a multipath environment, unless otherwise specified, errors of
this type (path related) should be retried using a different path, if
one is available.

Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: remove unused groups_only mode in ana log

groups_only mode in nvme_read_ana_log() is no longer used: remove it.

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: fix possible io hang after ctrl reconnect

The following scenario results in an IO hang:
1) ctrl completes a request with NVME_SC_ANA_TRANSITION.
NVME_NS_ANA_PENDING bit in ns->flags is set and ana_work is triggered.
2) ana_work: nvme_read_ana_log() tries to get the ANA log page from the ctrl.
This fails because ctrl disconnects.
Therefore nvme_update_ns_ana_state() is not called
and NVME_NS_ANA_PENDING bit in ns->flags is not cleared.
3) ctrl reconnects: nvme_mpath_init(ctrl,...) calls
nvme_read_ana_log(ctrl, groups_only=true).
However, nvme_update_ana_state() does not update namespaces
because nr_nsids = 0 (due to groups_only mode).
4) scan_work calls nvme_validate_ns() finds the ns and re-validates OK.

Result:
The ctrl is now live but NVME_NS_ANA_PENDING bit in ns->flags is still set.
Consequently ctrl will never be considered a viable path by __nvme_find_path().
IO will hang if ctrl is the only or the last path to the namespace.

More generally, while ctrl is reconnecting, its ANA state may change.
And because nvme_mpath_init() requests ANA log in groups_only mode,
these changes are not propagated to the existing ctrl namespaces.
This may result in a mal-function or an IO hang.

Solution:
nvme_mpath_init() will nvme_read_ana_log() with groups_only set to false.
This will not harm the new ctrl case (no namespaces present),
and will make sure the ANA state of namespaces gets updated after reconnect.

Note: Another option would be for nvme_mpath_init() to invoke
nvme_parse_ana_log(..., nvme_set_ns_ana_state) for each existing namespace.

Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: fix ana log nsid lookup when nsid is not found

ANA log parsing invokes nvme_update_ana_state() per ANA group desc.
This updates the state of namespaces with nsids in desc->nsids[].

Both ctrl->namespaces list and desc->nsids[] array are sorted by nsid.
Hence nvme_update_ana_state() performs a single walk over ctrl->namespaces:
- if current namespace matches the current desc->nsids[n],
this namespace is updated, and n is incremented.
- the process stops when it encounters the end of either
ctrl->namespaces end or desc->nsids[]

In case desc->nsids[n] does not match any of ctrl->namespaces,
the remaining nsids following desc->nsids[n] will not be updated.
Such situation was considered abnormal and generated WARN_ON_ONCE.

However ANA log MAY contain nsids not (yet) found in ctrl->namespaces.
For example, lets consider the following scenario:
- nvme0 exposes namespaces with nsids = [2, 3] to the host
- a new namespace nsid = 1 is added dynamically
- also, a ANA topology change is triggered
- NS_CHANGED aen is generated and triggers scan_work
- before scan_work discovers nsid=1 and creates a namespace, a NOTICE_ANA
aen was issues and ana_work receives ANA log with nsids=[1, 2, 3]

Result: ana_work fails to update ANA state on existing namespaces [2, 3]

Solution:
Change the way nvme_update_ana_state() namespace list walk
checks the current namespace against desc->nsids[n] as follows:
a) ns->head->ns_id < desc->nsids[n]: keep walking ctrl->namespaces.
b) ns->head->ns_id == desc->nsids[n]: match, update the namespace
c) ns->head->ns_id >= desc->nsids[n]: skip to desc->nsids[n+1]

This enables correct operation in the scenario described above.
This also allows ANA log to contain nsids currently invisible
to the host, i.e. inactive nsids.

Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Reviewed-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

nvme-multipath: fix possible I/O hang when paths are updated

nvme_state_set_live() making a path available triggers requeue_work
in order to resubmit requests that ended up on requeue_list when no
paths were available.

This requeue_work may race with concurrent nvme_ns_head_make_request()
that do not observe the live path yet.
Such concurrent requests may by made by either:
- New IO submission.
- Requeue_work triggered by nvme_failover_req() or another ana_work.

A race may cause requeue_work capture the state of requeue_list before
more requests get onto the list. These requests will stay on the list
forever unless requeue_work is triggered again.

In order to prevent such race, nvme_state_set_live() should
synchronize_srcu(&head->srcu) before triggering the requeue_work and
prevent nvme_ns_head_make_request referencing an old snapshot of the
path list.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anton Eidelman <anton@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: fix controller removal race with scan work

With multipath enabled, nvme_scan_work() can read from the device
(through nvme_mpath_add_disk()) and hang [1]. However, with fabrics,
once ctrl->state is set to NVME_CTRL_DELETING, the reads will hang
(see nvmf_check_ready()) and the mpath stack device make_request
will block if head->list is not empty. However, when the head->list
consistst of only DELETING/DEAD controllers, we should actually not
block, but rather fail immediately.

In addition, before we go ahead and remove the namespaces, make sure
to clear the current path and kick the requeue list so that the
request will fast fail upon requeuing.

[1]:
--
INFO: task kworker/u4:3:166 blocked for more than 120 seconds.
Not tainted 5.2.0-rc6-vmlocalyes-00005-g808c8c2dc0cf #316
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:3 D 0 166 2 0x80004000
Workqueue: nvme-wq nvme_scan_work
Call Trace:
__schedule+0x851/0x1400
schedule+0x99/0x210
io_schedule+0x21/0x70
do_read_cache_page+0xa57/0x1330
read_cache_page+0x4a/0x70
read_dev_sector+0xbf/0x380
amiga_partition+0xc4/0x1230
check_partition+0x30f/0x630
rescan_partitions+0x19a/0x980
__blkdev_get+0x85a/0x12f0
blkdev_get+0x2a5/0x790
__device_add_disk+0xe25/0x1250
device_add_disk+0x13/0x20
nvme_mpath_set_live+0x172/0x2b0
nvme_update_ns_ana_state+0x130/0x180
nvme_set_ns_ana_state+0x9a/0xb0
nvme_parse_ana_log+0x1c3/0x4a0
nvme_mpath_add_disk+0x157/0x290
nvme_validate_ns+0x1017/0x1bd0
nvme_scan_work+0x44d/0x6a0
process_one_work+0x7d7/0x1240
worker_thread+0x8e/0xff0
kthread+0x2c3/0x3b0
ret_from_fork+0x35/0x40

INFO: task kworker/u4:1:1034 blocked for more than 120 seconds.
Not tainted 5.2.0-rc6-vmlocalyes-00005-g808c8c2dc0cf #316
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:1 D 0 1034 2 0x80004000
Workqueue: nvme-delete-wq nvme_delete_ctrl_work
Call Trace:
__schedule+0x851/0x1400
schedule+0x99/0x210
schedule_timeout+0x390/0x830
wait_for_completion+0x1a7/0x310
__flush_work+0x241/0x5d0
flush_work+0x10/0x20
nvme_remove_namespaces+0x85/0x3d0
nvme_do_delete_ctrl+0xb4/0x1e0
nvme_delete_ctrl_work+0x15/0x20
process_one_work+0x7d7/0x1240
worker_thread+0x8e/0xff0
kthread+0x2c3/0x3b0
ret_from_fork+0x35/0x40
--

Reported-by: Logan Gunthorpe <logang@deltatee.com>
Tested-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

nvme: fix a possible deadlock when passthru commands sent to a multipath device

When the user issues a command with side effects, we will end up freezing
the namespace request queue when updating disk info (and the same for
the corresponding mpath disk node).

However, we are not freezing the mpath node request queue,
which means that mpath I/O can still come in and block on blk_queue_enter
(called from nvme_ns_head_make_request -> direct_make_request).

This is a deadlock, because blk_queue_enter will block until the inner
namespace request queue is unfroze, but that process is blocked because
the namespace revalidation is trying to update the mpath disk info
and freeze its request queue (which will never complete because
of the I/O that is blocked on blk_queue_enter).

Fix this by freezing all the subsystem nsheads request queues before
executing the passthru command. Given that these commands are infrequent
we should not worry about this temporary I/O freeze to keep things sane.

Here is the matching hang traces:
--
[ 374.465002] INFO: task systemd-udevd:17994 blocked for more than 122 seconds.
[ 374.472975] Not tainted 5.2.0-rc3-mpdebug+ #42
[ 374.478522] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 374.487274] systemd-udevd D 0 17994 1 0x00000000
[ 374.493407] Call Trace:
[ 374.496145] __schedule+0x2ef/0x620
[ 374.500047] schedule+0x38/0xa0
[ 374.503569] blk_queue_enter+0x139/0x220
[ 374.507959] ? remove_wait_queue+0x60/0x60
[ 374.512540] direct_make_request+0x60/0x130
[ 374.517219] nvme_ns_head_make_request+0x11d/0x420 [nvme_core]
[ 374.523740] ? generic_make_request_checks+0x307/0x6f0
[ 374.529484] generic_make_request+0x10d/0x2e0
[ 374.534356] submit_bio+0x75/0x140
[ 374.538163] ? guard_bio_eod+0x32/0xe0
[ 374.542361] submit_bh_wbc+0x171/0x1b0
[ 374.546553] block_read_full_page+0x1ed/0x330
[ 374.551426] ? check_disk_change+0x70/0x70
[ 374.556008] ? scan_shadow_nodes+0x30/0x30
[ 374.560588] blkdev_readpage+0x18/0x20
[ 374.564783] do_read_cache_page+0x301/0x860
[ 374.569463] ? blkdev_writepages+0x10/0x10
[ 374.574037] ? prep_new_page+0x88/0x130
[ 374.578329] ? get_page_from_freelist+0xa2f/0x1280
[ 374.583688] ? __alloc_pages_nodemask+0x179/0x320
[ 374.588947] read_cache_page+0x12/0x20
[ 374.593142] read_dev_sector+0x2d/0xd0
[ 374.597337] read_lba+0x104/0x1f0
[ 374.601046] find_valid_gpt+0xfa/0x720
[ 374.605243] ? string_nocheck+0x58/0x70
[ 374.609534] ? find_valid_gpt+0x720/0x720
[ 374.614016] efi_partition+0x89/0x430
[ 374.618113] ? string+0x48/0x60
[ 374.621632] ? snprintf+0x49/0x70
[ 374.625339] ? find_valid_gpt+0x720/0x720
[ 374.629828] check_partition+0x116/0x210
[ 374.634214] rescan_partitions+0xb6/0x360
[ 374.638699] __blkdev_reread_part+0x64/0x70
[ 374.643377] blkdev_reread_part+0x23/0x40
[ 374.647860] blkdev_ioctl+0x48c/0x990
[ 374.651956] block_ioctl+0x41/0x50
[ 374.655766] do_vfs_ioctl+0xa7/0x600
[ 374.659766] ? locks_lock_inode_wait+0xb1/0x150
[ 374.664832] ksys_ioctl+0x67/0x90
[ 374.668539] __x64_sys_ioctl+0x1a/0x20
[ 374.672732] do_syscall_64+0x5a/0x1c0
[ 374.676828] entry_SYSCALL_64_after_hwframe+0x44/0xa9

[ 374.738474] INFO: task nvmeadm:49141 blocked for more than 123 seconds.
[ 374.745871] Not tainted 5.2.0-rc3-mpdebug+ #42
[ 374.751419] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 374.760170] nvmeadm D 0 49141 36333 0x00004080
[ 374.766301] Call Trace:
[ 374.769038] __schedule+0x2ef/0x620
[ 374.772939] schedule+0x38/0xa0
[ 374.776452] blk_mq_freeze_queue_wait+0x59/0x100
[ 374.781614] ? remove_wait_queue+0x60/0x60
[ 374.786192] blk_mq_freeze_queue+0x1a/0x20
[ 374.790773] nvme_update_disk_info.isra.57+0x5f/0x350 [nvme_core]
[ 374.797582] ? nvme_identify_ns.isra.50+0x71/0xc0 [nvme_core]
[ 374.804006] __nvme_revalidate_disk+0xe5/0x110 [nvme_core]
[ 374.810139] nvme_revalidate_disk+0xa6/0x120 [nvme_core]
[ 374.816078] ? nvme_submit_user_cmd+0x11e/0x320 [nvme_core]
[ 374.822299] nvme_user_cmd+0x264/0x370 [nvme_core]
[ 374.827661] nvme_dev_ioctl+0x112/0x1d0 [nvme_core]
[ 374.833114] do_vfs_ioctl+0xa7/0x600
[ 374.837117] ? __audit_syscall_entry+0xdd/0x130
[ 374.842184] ksys_ioctl+0x67/0x90
[ 374.845891] __x64_sys_ioctl+0x1a/0x20
[ 374.850082] do_syscall_64+0x5a/0x1c0
[ 374.854178] entry_SYSCALL_64_after_hwframe+0x44/0xa9
--

Reported-by: James Puthukattukaran <james.puthukattukaran@oracle.com>
Tested-by: James Puthukattukaran <james.puthukattukaran@oracle.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

nvme: fix multipath crash when ANA is deactivated

Fix a crash with multipath activated. It happends when ANA log
page is larger than MDTS and because of that ANA is disabled.
The driver then tries to access unallocated buffer when connecting
to a nvme target. The signature is as follows:

[ 300.433586] nvme nvme0: ANA log page size (8208) larger than MDTS (8192).
[ 300.435387] nvme nvme0: disabling ANA support.
[ 300.437835] nvme nvme0: creating 4 I/O queues.
[ 300.459132] nvme nvme0: new ctrl: NQN "nqn.0.0.0", addr 10.91.0.1:8009
[ 300.464609] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[ 300.466342] #PF error: [normal kernel read fault]
[ 300.467385] PGD 0 P4D 0
[ 300.467987] Oops: 0000 [#1] SMP PTI
[ 300.468787] CPU: 3 PID: 50 Comm: kworker/u8:1 Not tainted 5.0.20kalray+ #4
[ 300.470264] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[ 300.471532] Workqueue: nvme-wq nvme_scan_work [nvme_core]
[ 300.472724] RIP: 0010:nvme_parse_ana_log+0x21/0x140 [nvme_core]
[ 300.474038] Code: 45 01 d2 d8 48 98 c3 66 90 0f 1f 44 00 00 41 57 41 56 41 55 41 54 55 53 48 89 fb 48 83 ec 08 48 8b af 20 0a 00 00 48 89 34 24 <66> 83 7d 08 00 0f 84 c6 00 00 00 44 8b 7d 14 49 89 d5 8b 55 10 48
[ 300.477374] RSP: 0018:ffffa50e80fd7cb8 EFLAGS: 00010296
[ 300.478334] RAX: 0000000000000001 RBX: ffff9130f1872258 RCX: 0000000000000000
[ 300.479784] RDX: ffffffffc06c4c30 RSI: ffff9130edad4280 RDI: ffff9130f1872258
[ 300.481488] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000044
[ 300.483203] R10: 0000000000000220 R11: 0000000000000040 R12: ffff9130f18722c0
[ 300.484928] R13: ffff9130f18722d0 R14: ffff9130edad4280 R15: ffff9130f18722c0
[ 300.486626] FS: 0000000000000000(0000) GS:ffff9130f7b80000(0000) knlGS:0000000000000000
[ 300.488538] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 300.489907] CR2: 0000000000000008 CR3: 00000002365e6000 CR4: 00000000000006e0
[ 300.491612] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 300.493303] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 300.494991] Call Trace:
[ 300.495645] nvme_mpath_add_disk+0x5c/0xb0 [nvme_core]
[ 300.496880] nvme_validate_ns+0x2ef/0x550 [nvme_core]
[ 300.498105] ? nvme_identify_ctrl.isra.45+0x6a/0xb0 [nvme_core]
[ 300.499539] nvme_scan_work+0x2b4/0x370 [nvme_core]
[ 300.500717] ? __switch_to_asm+0x35/0x70
[ 300.501663] process_one_work+0x171/0x380
[ 300.502340] worker_thread+0x49/0x3f0
[ 300.503079] kthread+0xf8/0x130
[ 300.503795] ? max_active_store+0x80/0x80
[ 300.504690] ? kthread_bind+0x10/0x10
[ 300.505502] ret_from_fork+0x35/0x40
[ 300.506280] Modules linked in: nvme_tcp nvme_rdma rdma_cm iw_cm ib_cm ib_core nvme_fabrics nvme_core xt_physdev ip6table_raw ip6table_mangle ip6table_filter ip6_tables xt_comment iptable_nat nf_nat_ipv4 nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 xt_CHECKSUM iptable_mangle iptable_filter veth ebtable_filter ebtable_nat ebtables iptable_raw vxlan ip6_udp_tunnel udp_tunnel sunrpc joydev pcspkr virtio_balloon br_netfilter bridge stp llc ip_tables xfs libcrc32c ata_generic pata_acpi virtio_net virtio_console net_failover virtio_blk failover ata_piix serio_raw libata virtio_pci virtio_ring virtio
[ 300.514984] CR2: 0000000000000008
[ 300.515569] ---[ end trace faa2eefad7e7f218 ]---
[ 300.516354] RIP: 0010:nvme_parse_ana_log+0x21/0x140 [nvme_core]
[ 300.517330] Code: 45 01 d2 d8 48 98 c3 66 90 0f 1f 44 00 00 41 57 41 56 41 55 41 54 55 53 48 89 fb 48 83 ec 08 48 8b af 20 0a 00 00 48 89 34 24 <66> 83 7d 08 00 0f 84 c6 00 00 00 44 8b 7d 14 49 89 d5 8b 55 10 48
[ 300.520353] RSP: 0018:ffffa50e80fd7cb8 EFLAGS: 00010296
[ 300.521229] RAX: 0000000000000001 RBX: ffff9130f1872258 RCX: 0000000000000000
[ 300.522399] RDX: ffffffffc06c4c30 RSI: ffff9130edad4280 RDI: ffff9130f1872258
[ 300.523560] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000044
[ 300.524734] R10: 0000000000000220 R11: 0000000000000040 R12: ffff9130f18722c0
[ 300.525915] R13: ffff9130f18722d0 R14: ffff9130edad4280 R15: ffff9130f18722c0
[ 300.527084] FS: 0000000000000000(0000) GS:ffff9130f7b80000(0000) knlGS:0000000000000000
[ 300.528396] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 300.529440] CR2: 0000000000000008 CR3: 00000002365e6000 CR4: 00000000000006e0
[ 300.530739] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 300.531989] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 300.533264] Kernel panic - not syncing: Fatal exception
[ 300.534338] Kernel Offset: 0x17c00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 300.536227] ---[ end Kernel panic - not syncing: Fatal exception ]---

Condition check refactoring from Christoph Hellwig.

Signed-off-by: Marta Rybczynska <marta.rybczynska@kalray.eu>
Tested-by: Jean-Baptiste Riaux <jbriaux@kalray.eu>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: do not select namespaces which are about to be removed

nvme_ns_remove() will first set the NVME_NS_REMOVING flag before removing
it from the list at the very last step.
So to avoid selecting a namespace in nvme_find_path() which is about to be
removed check the NVME_NS_REMOVING flag, too, when selecting a new path.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: also check for a disabled path if there is a single sibling

When we have a singular list in nvme_round_robin_path() we still
need to check its validity.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: factor out a nvme_path_is_disabled helper

Factor our a common helper to check if a path has been disabled
by something other than the per-namespace ANA state.

Signed-off-by: Hannes Reinecke <hare@suse.com>
[hch: split from a bigger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: avoid crash on invalid subsystem cntlid enumeration

A process holding an open reference to a removed disk prevents it
from completing deletion, so its name continues to exist. A subsequent
gendisk creation may have the same cntlid which risks collision when
using that for the name. Use the unique ctrl->instance instead.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: don't print ANA group state by default

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

nvme-multipath: split bios with the ns_head bio_set before submitting

If the bio is moved to a different queue via blk_steal_bios() and
the original queue is destroyed in nvme_remove_ns() we'll be ending
with a crash in bio_endio() as the mempool for the split bio bvecs
had already been destroyed.
So split the bio using the original queue (which will remain during the
lifetime of the bio) before sending it down to the underlying device.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: relax ANA state check

When undergoing state transitions I/O might be requeued, hence
we should always call nvme_mpath_set_live() to schedule requeue_work
whenever the nvme device is live, independent on whether the
old state was live or not.

Signed-off-by: Martin George <marting@netapp.com>
Signed-off-by: Gargi Srinivas <sring@netapp.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: convert to SPDX identifiers

Update license to use SPDX-License-Identifier instead of verbose license
text.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>

nvme-multipath: round-robin I/O policy

Implement a simple round-robin I/O policy for multipathing. Path
selection is done in two rounds, first iterating across all optimized
paths, and if that doesn't return any valid paths, iterate over all
optimized and non-optimized paths. If no paths are found, use the
existing algorithm. Also add a sysfs attribute 'iopolicy' to switch
between the current NUMA-aware I/O policy and the 'round-robin' I/O
policy.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme-multipath: drop optimization for static ANA group IDs

Bit 6 in the ANACAP field is used to indicate that the ANA group ID
doesn't change while the namespace is attached to the controller.
There is an optimisation in the code to only allocate space
for the ANA group header, as the namespace list won't change and
hence would not need to be refreshed.
However, this optimisation was never carried over to the actual
workflow, which always assumes that the buffer is large enough
to hold the ANA header _and_ the namespace list.
So drop this optimisation and always allocate enough space.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: zero out ANA log buffer

When nvme_init_identify() fails the ANA log buffer is deallocated
but _not_ set to NULL. This can cause double free oops when this
controller is deleted without ever being reconnected.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: add a numa_node field to struct nvme_ctrl

Instead of directly poking into the struct device add a new numa_node
field to struct nvme_ctrl. This allows fabrics drivers where ctrl->dev
is a virtual device to support NUMA affinity as well.

Also expose the field as a sysfs attribute, and populate it for the
RDMA and FC transports.

Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-mpath: remove I/O polling support

The ->poll_fn has been stale for a while, as a lot of places check for mq
ops. But there is no real point in it anyway, as we don't even use
the multipath code for subsystems without multiple ports, which is usually
what we do high performance I/O to. If it really becomes an issue we
should rework the nvme code to also skip the multipath code for any
private namespace, even if that could mean some trouble when rescanning.

Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: make blk_poll() take a parameter on whether to spin or not

blk_poll() has always kept spinning until it found an IO. This is
fine for SYNC polling, since we need to find one request we have
pending, but in preparation for ASYNC polling it can be beneficial
to just check if we have any entries available or not.

Existing callers are converted to pass in 'spin == true', to retain
the old behavior.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: have ->poll_fn() return number of entries polled

We currently only really support sync poll, ie poll with 1 IO in flight.
This prepares us for supporting async poll.

Note that the returned value isn't necessarily 100% accurate. If poll
races with IRQ completion, we assume that the fact that the task is now
runnable means we found at least one entry. In reality it could be more
than 1, or not even 1. This is fine, the caller will just need to take
this into account.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the lock argument to blk_alloc_queue_node

With the legacy request path gone there is no real need to override the
queue_lock.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: make sure ns head inherits underlying device limits

Whenever we update ns_head info, we need to make sure it is still
compatible with all underlying backing devices because although nvme
multipath doesn't have any explicit use of these limits, other devices
can still be stacked on top of it which may rely on the underlying limits.
Start with unlimited stacking limits, and every info update iterate over
siblings and adjust queue limits.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: update node paths after adding new path

The nvme namespace paths were being updated only when the current path
was not set or nonoptimized. If a new path comes online that is a better
path for its NUMA node, the multipath selector may continue using the
previously set path on a potentially further node.

This patch re-runs the path assignment after successfully adding a new
optimized path.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: take node locality into account when selecting a path

Make current_path an array with an entry for every possible node, and
cache the best path on a per-node basis. Take the node distance into
account when selecting it. This is primarily useful for dual-ported PCIe
devices which are connected to PCIe root ports on different sockets.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>

nvme: call nvme_complete_rq when nvmf_check_ready fails for mpath I/O

When an io is rejected by nvmf_check_ready() due to validation of the
controller state, the nvmf_fail_nonready_command() will normally return
BLK_STS_RESOURCE to requeue and retry. However, if the controller is
dying or the I/O is marked for NVMe multipath, the I/O is failed so that
the controller can terminate or so that the io can be issued on a
different path. Unfortunately, as this reject point is before the
transport has accepted the command, blk-mq ends up completing the I/O
and never calls nvme_complete_rq(), which is where multipath may preserve
or re-route the I/O. The end result is, the device user ends up seeing an
EIO error.

Example: single path connectivity, controller is under load, and a reset
is induced. An I/O is received:

a) while the reset state has been set but the queues have yet to be
stopped; or
b) after queues are started (at end of reset) but before the reconnect
has completed.

The I/O finishes with an EIO status.

This patch makes the following changes:

- Adds the HOST_PATH_ERROR pathing status from TP4028
- Modifies the reject point such that it appears to queue successfully,
but actually completes the io with the new pathing status and calls
nvme_complete_rq().
- nvme_complete_rq() recognizes the new status, avoids resetting the
controller (likely was already done in order to get this new status),
and calls the multipather to clear the current path that errored.
This allows the next command (retry or new command) to select a new
path if there is one.

Signed-off-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: register ns_id attributes as default sysfs groups

We should be registering the ns_id attribute as default sysfs
attribute groups, otherwise we have a race condition between
the uevent and the attributes appearing in sysfs.

Suggested-by: Bart van Assche <bvanassche@acm.org>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: genhd: add 'groups' argument to device_add_disk

Update device_add_disk() to take an 'groups' argument so that
individual drivers can register a device with additional sysfs
attributes.
This avoids race condition the driver would otherwise have if these
groups were to be created with sysfs_add_groups().

Signed-off-by: Martin Wilck <martin.wilck@suse.com>
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: properly propagate errors in nvme_mpath_init

Signed-off-by: Susobhan Dey <susobhan.dey@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: fixup crash on failed discovery

When the initial discovery fails the subsystem hasn't been setup yet
in nvme_mpath_stop, and we can't dereference ctrl->subsys.

Fixes: 0d0b660f ("nvme: add ANA support")
Signed-off-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: add ANA support

Add support for Asynchronous Namespace Access as specified in NVMe 1.3
TP 4004. With ANA each namespace attached to a controller belongs to an
ANA group that describes the characteristics of accessing the namespaces
through this controller. In the optimized and non-optimized states
namespaces can be accessed regularly, although in a multi-pathing
environment we should always prefer to access a namespace through a
controller where an optimized relationship exists. Namespaces in
Inaccessible, Permanent-Loss or Change state for a given controller
should not be accessed.

The states are updated through reading the ANA log page, which is read
once during controller initialization, whenever the ANA change notice
AEN is received, or when one of the ANA specific status codes that
signal a state change is received on a command.

The ANA state is kept in the nvme_ns structure, which makes the checks in
the fast path very simple. Updating the ANA state when reading the log
page is also very simple, the only downside is that finding the initial
ANA state when scanning for namespaces is a bit cumbersome.

The gendisk for a ns_head is only registered once a live path for it
exists. Without that the kernel would hang during partition scanning.

Includes fixes and improvements from Hannes Reinecke.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

nvme: remove nvme_req_needs_failover

Now that we just call out to blk_path_error there isn't really any good
reason to not merge it into the only caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

nvme: add bio remapping tracepoint

Adding a tracepoint to trace bio remapping for native nvme multipath.

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

nvme/multipath: Fix multipath disabled naming collisions

When CONFIG_NVME_MULTIPATH is set, but we're not using nvme to multipath,
namespaces with multiple paths were not creating unique names due to
reusing the same instance number from the namespace's head.

This patch fixes this by falling back to the non-multipath naming method
when the parameter disabled using multipath.

Reported-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme/multipath: Disable runtime writable enabling parameter

We can't allow the user to change multipath settings at runtime, as this
will create naming conflicts due to the different naming schemes used
for each mode.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: change namespaces_mutext to namespaces_rwsem

namespaces_mutext is used to synchronize the operations on ctrl
namespaces list. Most of the time, it is a read operation.

On the other hand, there are many interfaces in nvme core that
need this lock, such as nvme_wait_freeze, and even more interfaces
will be added. If we use mutex here, circular dependency could be
introduced easily. For example:
context A context B
nvme_xxx nvme_xxx
hold namespaces_mutext require namespaces_mutext
sync context B

So it is better to change it from mutex to rwsem.

Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: Use blk_queue_flag_*() in drivers instead of queue_flag_*()

This patch has been generated as follows:

for verb in set_unlocked clear_unlocked set clear; do
replace-in-files queue_flag_${verb} blk_queue_flag_${verb%_unlocked} \
$(git grep -lw queue_flag_${verb} drivers block/bsg*)
done

Except for protecting all queue flag changes with the queue lock
this patch does not change any functionality.

Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Revert "nvme: create 'slaves' and 'holders' entries for hidden controllers"

This reverts commit e9a48034d7d1318ece7d4a235838a86c94db9d68.

The slaves and holders link for the hidden gendisks confuse lsblk so that
it errors out on, or doesn't report the nvme multipath devices. Given
that we don't need holder relationships for something that can't even be
directly accessed we should just stop creating those links.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Potnuri Bharat Teja <bharat@chelsio.com>
Cc: stable@vger.kernel.org
Signed-off-by: Keith Busch <keith.busch@intel.com>

block: Add 'lock' as third argument to blk_alloc_queue_node()

This patch does not change any functionality.

Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme-multipath: fix sysfs dangerously created links

If multipathing is enabled, each NVMe subsystem creates a head
namespace (e.g., nvme0n1) and multiple private namespaces
(e.g., nvme0c0n1 and nvme0c1n1) in sysfs. When creating links for
private namespaces, links of head namespace are used, so the
namespace creation order must be followed (e.g., nvme0n1 ->
nvme0c1n1). If the order is not followed, links of sysfs will be
incomplete or kernel panic will occur.

The kernel panic was:
kernel BUG at fs/sysfs/symlink.c:27!
Call Trace:
nvme_mpath_add_disk_links+0x5d/0x80 [nvme_core]
nvme_validate_ns+0x5c2/0x850 [nvme_core]
nvme_scan_work+0x1af/0x2d0 [nvme_core]

Correct order
Context A Context B
nvme0n1
nvme0c0n1 nvme0c1n1

Incorrect order
Context A Context B
nvme0c1n1
nvme0n1
nvme0c0n1

The nvme_mpath_add_disk (for creating head namespace) is called
just before the nvme_mpath_add_disk_links (for creating private
namespaces). In nvme_mpath_add_disk, the first context acquires
the lock of subsystem and creates a head namespace, and other
contexts do nothing by checking GENHD_FL_UP of a head namespace
after waiting to acquire the lock. We verified the code with or
without multipathing using three vendors of dual-port NVMe SSDs.

Signed-off-by: Baegjae Sung <baegjae@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <keith.busch@intel.com>

nvme/multipath: Use blk_path_error

Uses common code for determining if an error should be retried on
alternate path.

Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme/multipath: Consult blk_status_t for failover

This removes nvme multipath's specific status decoding to see if failover
is needed, using the generic blk_status_t that was decoded earlier. This
abstraction from the raw NVMe status means all status decoding exists
in one place.

Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: fix spelling mistake: "requeing" -> "requeuing"

Trivial fix to spelling mistake in dev_warn_ratelimited message text

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: create 'slaves' and 'holders' entries for hidden controllers

When creating nvme multipath devices we should populate the 'slaves' and
'holders' directorys properly to aid userspace topology detection.

Signed-off-by: Hannes Reinecke <hare@suse.com>
[hch: split from a larger patch, compile fix for CONFIG_NVME_MULTIPATH=n]
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: also expose the namespace identification sysfs files for mpath nodes

We do this by adding a helper that returns the ns_head for a device that
can belong to either the per-controller or per-subsystem block device
nodes, and otherwise reuse all the existing code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvme: implement multipath access to nvme subsystems

This patch adds native multipath support to the nvme driver. For each
namespace we create only single block device node, which can be used
to access that namespace through any of the controllers that refer to it.
The gendisk for each controllers path to the name space still exists
inside the kernel, but is hidden from userspace. The character device
nodes are still available on a per-controller basis. A new link from
the sysfs directory for the subsystem allows to find all controllers
for a given subsystem.

Currently we will always send I/O to the first available path, this will
be changed once the NVMe Asynchronous Namespace Access (ANA) TP is
ratified and implemented, at which point we will look at the ANA state
for each namespace. Another possibility that was prototyped is to
use the path that is closes to the submitting NUMA code, which will be
mostly interesting for PCI, but might also be useful for RDMA or FC
transports in the future. There is not plan to implement round robin
or I/O service time path selectors, as those are not scalable with
the performance rates provided by NVMe.

The multipath device will go away once all paths to it disappear,
any delay to keep it alive needs to be implemented at the controller
level.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>