Factor out a self-contained helper to just lookup a mddev by the dev_t
"unit".

Cc: stable@vger.kernel.org
Reviewed-by: NHeming Zhao <heming.zhao@suse.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSong Liu <song@kernel.org>

commit d3374825 ("md: make devices disappear when they are no longer
needed.") introduced protection between mddev creating & removing. The
md_open shouldn't create mddev when all_mddevs list doesn't contain
mddev. With currently code logic, there will be very easy to trigger
soft lockup in non-preempt env.

This patch changes md_open returning from -ERESTARTSYS to -EBUSY, which
will break the infinitely retry when md_open enter racing area.

This patch is partly fix soft lockup issue, full fix needs mddev_find
is split into two functions: mddev_find & mddev_find_or_alloc. And
md_open should call new mddev_find (it only does searching job).

For more detail, please refer with Christoph's "split mddev_find" patch
in later commits.

*** env ***
kvm-qemu VM 2C1G with 2 iscsi luns
kernel should be non-preempt

*** script ***

about trigger every time with below script

```
1  node1="mdcluster1"
2  node2="mdcluster2"
3
4  mdadm -Ss
5  ssh ${node2} "mdadm -Ss"
6  wipefs -a /dev/sda /dev/sdb
7  mdadm -CR /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sda \
   /dev/sdb --assume-clean
8
9  for i in {1..10}; do
10    echo ==== $i ====;
11
12    echo "test  ...."
13    ssh ${node2} "mdadm -A /dev/md0 /dev/sda /dev/sdb"
14    sleep 1
15
16    echo "clean  ....."
17    ssh ${node2} "mdadm -Ss"
18 done
```

I use mdcluster env to trigger soft lockup, but it isn't mdcluster
speical bug. To stop md array in mdcluster env will do more jobs than
non-cluster array, which will leave enough time/gap to allow kernel to
run md_open.

*** stack ***

```
[  884.226509]  mddev_put+0x1c/0xe0 [md_mod]
[  884.226515]  md_open+0x3c/0xe0 [md_mod]
[  884.226518]  __blkdev_get+0x30d/0x710
[  884.226520]  ? bd_acquire+0xd0/0xd0
[  884.226522]  blkdev_get+0x14/0x30
[  884.226524]  do_dentry_open+0x204/0x3a0
[  884.226531]  path_openat+0x2fc/0x1520
[  884.226534]  ? seq_printf+0x4e/0x70
[  884.226536]  do_filp_open+0x9b/0x110
[  884.226542]  ? md_release+0x20/0x20 [md_mod]
[  884.226543]  ? seq_read+0x1d8/0x3e0
[  884.226545]  ? kmem_cache_alloc+0x18a/0x270
[  884.226547]  ? do_sys_open+0x1bd/0x260
[  884.226548]  do_sys_open+0x1bd/0x260
[  884.226551]  do_syscall_64+0x5b/0x1e0
[  884.226554]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
```

*** rootcause ***

"mdadm -A" (or other array assemble commands) will start a daemon "mdadm
--monitor" by default. When "mdadm -Ss" is running, the stop action will
wakeup "mdadm --monitor". The "--monitor" daemon will immediately get
info from /proc/mdstat. This time mddev in kernel still exist, so
/proc/mdstat still show md device, which makes "mdadm --monitor" to open
/dev/md0.

The previously "mdadm -Ss" is removing action, the "mdadm --monitor"
open action will trigger md_open which is creating action. Racing is
happening.

```
<thread 1>: "mdadm -Ss"
md_release
  mddev_put deletes mddev from all_mddevs
  queue_work for mddev_delayed_delete
  at this time, "/dev/md0" is still available for opening

<thread 2>: "mdadm --monitor ..."
md_open
 + mddev_find can't find mddev of /dev/md0, and create a new mddev and
 |    return.
 + trigger "if (mddev->gendisk != bdev->bd_disk)" and return
      -ERESTARTSYS.
```

In non-preempt kernel, <thread 2> is occupying on current CPU. and
mddev_delayed_delete which was created in <thread 1> also can't be
schedule.

In preempt kernel, it can also trigger above racing. But kernel doesn't
allow one thread running on a CPU all the time. after <thread 2> running
some time, the later "mdadm -A" (refer above script line 13) will call
md_alloc to alloc a new gendisk for mddev. it will break md_open
statement "if (mddev->gendisk != bdev->bd_disk)" and return 0 to caller,
the soft lockup is broken.

Cc: stable@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NZhao Heming <heming.zhao@suse.com>
Signed-off-by: NSong Liu <song@kernel.org>

Fixes the following W=1 kernel build warning(s):

 from drivers/block/drbd/drbd_nl.c:24:
 drivers/block/drbd/drbd_nl.c: In function ‘drbd_adm_attach’:
 drivers/block/drbd/drbd_nl.c:1968:10: warning: implicit conversion from ‘enum drbd_state_rv’ to ‘enum drbd_ret_code’ [-Wenum-conversion]
 drivers/block/drbd/drbd_nl.c:930: warning: Function parameter or member 'flags' not described in 'drbd_determine_dev_size'
 drivers/block/drbd/drbd_nl.c:930: warning: Function parameter or member 'rs' not described in 'drbd_determine_dev_size'
 drivers/block/drbd/drbd_nl.c:1148: warning: Function parameter or member 'dc' not described in 'drbd_check_al_size'

Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-12-lee.jones@linaro.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Fixes the following W=1 kernel build warning(s):

 drivers/block/xen-blkfront.c:1960: warning: Function parameter or member 'dev' not described in 'blkfront_probe'
 drivers/block/xen-blkfront.c:1960: warning: Function parameter or member 'id' not described in 'blkfront_probe'
 drivers/block/xen-blkfront.c:1960: warning: expecting prototype for Allocate the basic(). Prototype was for blkfront_probe() instead
 drivers/block/xen-blkfront.c:2085: warning: Function parameter or member 'dev' not described in 'blkfront_resume'
 drivers/block/xen-blkfront.c:2085: warning: expecting prototype for or a backend(). Prototype was for blkfront_resume() instead
 drivers/block/xen-blkfront.c:2444: warning: wrong kernel-doc identifier on line:

Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: "Roger Pau Monné" <roger.pau@citrix.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: xen-devel@lists.xenproject.org
Cc: linux-block@vger.kernel.org
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Acked-by: NRoger Pau Monné <roger.pau@citrix.com>
Link: https://lore.kernel.org/r/20210312105530.2219008-11-lee.jones@linaro.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Fixes the following W=1 kernel build warning(s):

 drivers/block/drbd/drbd_receiver.c:1641: warning: Function parameter or member 'op' not described in 'drbd_submit_peer_request'
 drivers/block/drbd/drbd_receiver.c:1641: warning: Function parameter or member 'op_flags' not described in 'drbd_submit_peer_request'
 drivers/block/drbd/drbd_receiver.c:1641: warning: Function parameter or member 'fault_type' not described in 'drbd_submit_peer_request'

Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-10-lee.jones@linaro.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Fixes the following W=1 kernel build warning(s):

 drivers/block/drbd/drbd_main.c:278: warning: Function parameter or member 'connection' not described in 'tl_clear'
 drivers/block/drbd/drbd_main.c:278: warning: Excess function parameter 'device' description in 'tl_clear'
 drivers/block/drbd/drbd_main.c:489: warning: Function parameter or member 'cpu_mask' not described in 'drbd_calc_cpu_mask'
 drivers/block/drbd/drbd_main.c:528: warning: Excess function parameter 'device' description in 'drbd_thread_current_set_cpu'
 drivers/block/drbd/drbd_main.c:549: warning: Function parameter or member 'connection' not described in 'drbd_header_size'
 drivers/block/drbd/drbd_main.c:1204: warning: Function parameter or member 'device' not described in 'send_bitmap_rle_or_plain'
 drivers/block/drbd/drbd_main.c:1204: warning: Function parameter or member 'c' not described in 'send_bitmap_rle_or_plain'
 drivers/block/drbd/drbd_main.c:1335: warning: Function parameter or member 'peer_device' not described in '_drbd_send_ack'
 drivers/block/drbd/drbd_main.c:1335: warning: Excess function parameter 'device' description in '_drbd_send_ack'
 drivers/block/drbd/drbd_main.c:1379: warning: Function parameter or member 'peer_device' not described in 'drbd_send_ack'
 drivers/block/drbd/drbd_main.c:1379: warning: Excess function parameter 'device' description in 'drbd_send_ack'
 drivers/block/drbd/drbd_main.c:1892: warning: Function parameter or member 'connection' not described in 'drbd_send_all'
 drivers/block/drbd/drbd_main.c:1892: warning: Function parameter or member 'sock' not described in 'drbd_send_all'
 drivers/block/drbd/drbd_main.c:1892: warning: Function parameter or member 'buffer' not described in 'drbd_send_all'
 drivers/block/drbd/drbd_main.c:1892: warning: Function parameter or member 'size' not described in 'drbd_send_all'
 drivers/block/drbd/drbd_main.c:1892: warning: Function parameter or member 'msg_flags' not described in 'drbd_send_all'
 drivers/block/drbd/drbd_main.c:3525: warning: Function parameter or member 'flags' not described in 'drbd_queue_bitmap_io'
 drivers/block/drbd/drbd_main.c:3563: warning: Function parameter or member 'flags' not described in 'drbd_bitmap_io'

Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-9-lee.jones@linaro.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Fixes the following W=1 kernel build warning(s):

 from drivers/block/drbd/drbd_nl.c:24:
 drivers/block/drbd/drbd_nl.c: In function ‘drbd_adm_set_role’:
 drivers/block/drbd/drbd_nl.c:793:11: warning: implicit conversion from ‘enum drbd_state_rv’ to ‘enum drbd_ret_code’ [-Wenum-conversion]
 drivers/block/drbd/drbd_nl.c:795:11: warning: implicit conversion from ‘enum drbd_state_rv’ to ‘enum drbd_ret_code’ [-Wenum-conversion]
 drivers/block/drbd/drbd_nl.c: In function ‘drbd_adm_attach’:
 drivers/block/drbd/drbd_nl.c:1965:10: warning: implicit conversion from ‘enum drbd_state_rv’ to ‘enum drbd_ret_code’ [-Wenum-conversion]
 drivers/block/drbd/drbd_nl.c: In function ‘drbd_adm_connect’:
 drivers/block/drbd/drbd_nl.c:2690:10: warning: implicit conversion from ‘enum drbd_state_rv’ to ‘enum drbd_ret_code’ [-Wenum-conversion]
 drivers/block/drbd/drbd_nl.c: In function ‘drbd_adm_disconnect’:
 drivers/block/drbd/drbd_nl.c:2803:11: warning: implicit conversion from ‘enum drbd_state_rv’ to ‘enum drbd_ret_code’ [-Wenum-conversion]

Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-8-lee.jones@linaro.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

[P_RETRY_WRITE] is initialised more than once.

Fixes the following W=1 kernel build warning(s):

 drivers/block/drbd/drbd_main.c: In function ‘cmdname’:
 drivers/block/drbd/drbd_main.c:3660:22: warning: initialized field overwritten [-Woverride-init]
 drivers/block/drbd/drbd_main.c:3660:22: note: (near initialization for ‘cmdnames[44]’)

Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-7-lee.jones@linaro.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Fixes the following W=1 kernel build warning(s):

 drivers/block/drbd/drbd_receiver.c:265: warning: Function parameter or member 'peer_device' not described in 'drbd_alloc_pages'
 drivers/block/drbd/drbd_receiver.c:265: warning: Excess function parameter 'device' description in 'drbd_alloc_pages'
 drivers/block/drbd/drbd_receiver.c:1362: warning: Function parameter or member 'connection' not described in 'drbd_may_finish_epoch'
 drivers/block/drbd/drbd_receiver.c:1362: warning: Excess function parameter 'device' description in 'drbd_may_finish_epoch'
 drivers/block/drbd/drbd_receiver.c:1451: warning: Function parameter or member 'resource' not described in 'drbd_bump_write_ordering'
 drivers/block/drbd/drbd_receiver.c:1451: warning: Function parameter or member 'bdev' not described in 'drbd_bump_write_ordering'
 drivers/block/drbd/drbd_receiver.c:1451: warning: Excess function parameter 'connection' description in 'drbd_bump_write_ordering'
 drivers/block/drbd/drbd_receiver.c:1643: warning: Function parameter or member 'op' not described in 'drbd_submit_peer_request'
 drivers/block/drbd/drbd_receiver.c:1643: warning: Function parameter or member 'op_flags' not described in 'drbd_submit_peer_request'
 drivers/block/drbd/drbd_receiver.c:1643: warning: Function parameter or member 'fault_type' not described in 'drbd_submit_peer_request'
 drivers/block/drbd/drbd_receiver.c:1643: warning: Excess function parameter 'rw' description in 'drbd_submit_peer_request'
 drivers/block/drbd/drbd_receiver.c:3055: warning: Function parameter or member 'peer_device' not described in 'drbd_asb_recover_0p'
 drivers/block/drbd/drbd_receiver.c:3138: warning: Function parameter or member 'peer_device' not described in 'drbd_asb_recover_1p'
 drivers/block/drbd/drbd_receiver.c:3195: warning: Function parameter or member 'peer_device' not described in 'drbd_asb_recover_2p'
 drivers/block/drbd/drbd_receiver.c:4684: warning: Function parameter or member 'peer_device' not described in 'receive_bitmap_plain'
 drivers/block/drbd/drbd_receiver.c:4684: warning: Function parameter or member 'size' not described in 'receive_bitmap_plain'
 drivers/block/drbd/drbd_receiver.c:4684: warning: Function parameter or member 'p' not described in 'receive_bitmap_plain'
 drivers/block/drbd/drbd_receiver.c:4684: warning: Function parameter or member 'c' not described in 'receive_bitmap_plain'
 drivers/block/drbd/drbd_receiver.c:4738: warning: Function parameter or member 'peer_device' not described in 'recv_bm_rle_bits'
 drivers/block/drbd/drbd_receiver.c:4738: warning: Function parameter or member 'p' not described in 'recv_bm_rle_bits'
 drivers/block/drbd/drbd_receiver.c:4738: warning: Function parameter or member 'c' not described in 'recv_bm_rle_bits'
 drivers/block/drbd/drbd_receiver.c:4738: warning: Function parameter or member 'len' not described in 'recv_bm_rle_bits'
 drivers/block/drbd/drbd_receiver.c:4807: warning: Function parameter or member 'peer_device' not described in 'decode_bitmap_c'
 drivers/block/drbd/drbd_receiver.c:4807: warning: Function parameter or member 'p' not described in 'decode_bitmap_c'
 drivers/block/drbd/drbd_receiver.c:4807: warning: Function parameter or member 'c' not described in 'decode_bitmap_c'
 drivers/block/drbd/drbd_receiver.c:4807: warning: Function parameter or member 'len' not described in 'decode_bitmap_c'

Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-6-lee.jones@linaro.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Fixes the following W=1 kernel build warning(s):

 drivers/block/drbd/drbd_state.c:913: warning: Function parameter or member 'connection' not described in 'is_valid_soft_transition'
 drivers/block/drbd/drbd_state.c:913: warning: Excess function parameter 'device' description in 'is_valid_soft_transition'
 drivers/block/drbd/drbd_state.c:1054: warning: Function parameter or member 'warn' not described in 'sanitize_state'
 drivers/block/drbd/drbd_state.c:1054: warning: Excess function parameter 'warn_sync_abort' description in 'sanitize_state'
 drivers/block/drbd/drbd_state.c:1703: warning: Function parameter or member 'state_change' not described in 'after_state_ch'

Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-5-lee.jones@linaro.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Fixes the following W=1 kernel build warning(s):

 drivers/block/mtip32xx/mtip32xx.c: In function ‘mtip_standby_immediate’:
 drivers/block/mtip32xx/mtip32xx.c:1216:16: warning: variable ‘start’ set but not used [-Wunused-but-set-variable]

Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-4-lee.jones@linaro.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Fixes the following W=1 kernel build warning(s):

 drivers/block/drbd/drbd_interval.c:11: warning: Function parameter or member 'node' not described in 'interval_end'
 drivers/block/drbd/drbd_interval.c:26: warning: Function parameter or member 'root' not described in 'drbd_insert_interval'
 drivers/block/drbd/drbd_interval.c:26: warning: Function parameter or member 'this' not described in 'drbd_insert_interval'
 drivers/block/drbd/drbd_interval.c:70: warning: Function parameter or member 'root' not described in 'drbd_contains_interval'
 drivers/block/drbd/drbd_interval.c:96: warning: Function parameter or member 'root' not described in 'drbd_remove_interval'
 drivers/block/drbd/drbd_interval.c:96: warning: Function parameter or member 'this' not described in 'drbd_remove_interval'
 drivers/block/drbd/drbd_interval.c:113: warning: Function parameter or member 'root' not described in 'drbd_find_overlap'

Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: drbd-dev@lists.linbit.com
Cc: linux-block@vger.kernel.org
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-3-lee.jones@linaro.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Pull NVMe updates from Christoph:

"nvme updates for Linux 5.13

 - fix handling of very large MDTS values (Bart Van Assche)
 - retrigger ANA log update if group descriptor isn't found
   (Hannes Reinecke)
 - fix locking contexts in nvme-tcp and nvmet-tcp (Sagi Grimberg)
 - return proper error code from discovery ctrl (Hou Pu)
 - verify the SGLS field in nvmet-tcp and nvmet-fc (Max Gurtovoy)
 - disallow passthru cmd from targeting a nsid != nsid of the block dev
   (Niklas Cassel)
 - do not allow model_number exceed 40 bytes in nvmet (Noam Gottlieb)
 - enable optional queue idle period tracking in nvmet-tcp
   (Mark Wunderlich)
 - various cleanups and optimizations (Chaitanya Kulkarni, Kanchan Joshi)
 - expose fast_io_fail_tmo in sysfs (Daniel Wagner)
 - implement non-MDTS command limits (Keith Busch)
 - reduce warnings for unhandled command effects (Keith Busch)
 - allocate storage for the SQE as part of the nvme_request (Keith Busch)"

* tag 'nvme-5.13-2021-04-06' of git://git.infradead.org/nvme: (33 commits)
  nvme: fix handling of large MDTS values
  nvme: implement non-mdts command limits
  nvme: disallow passthru cmd from targeting a nsid != nsid of the block dev
  nvme: retrigger ANA log update if group descriptor isn't found
  nvme: export fast_io_fail_tmo to sysfs
  nvme: remove superfluous else in nvme_ctrl_loss_tmo_store
  nvme: use sysfs_emit instead of sprintf
  nvme-fc: check sgl supported by target
  nvme-tcp: check sgl supported by target
  nvmet-tcp: enable optional queue idle period tracking
  nvmet-tcp: fix incorrect locking in state_change sk callback
  nvme-tcp: block BH in sk state_change sk callback
  nvmet: return proper error code from discovery ctrl
  nvme: warn of unhandled effects only once
  nvme: use driver pdu command for passthrough
  nvme-pci: allocate nvme_command within driver pdu
  nvmet: do not allow model_number exceed 40 bytes
  nvmet: remove unnecessary ctrl parameter
  nvmet-fc: update function documentation
  nvme-fc: fix the function documentation comment
  ...

Instead of triggering an integer overflow and undefined behavior if MDTS is
large, set max_hw_sectors to UINT_MAX.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
[hch: rebased to account for the new nvme_mps_to_sectors helper]
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Commands that access LBA contents without a data transfer between the
host historically have not had a spec defined upper limit. The driver
set the queue constraints for such commands to the max data transfer
size just to be safe, but this artificial constraint frequently limits
devices below their capabilities.

The NVMe Workgroup ratified TP4040 defines how a controller may
advertise their non-MDTS limits. Use these if provided and default to
the current constraints if not. Since the Dataset Management command
limits are defined in logical blocks, but without a namespace to tell us
the logical block size, the code defaults to the safe 512b size.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

When a passthru command targets a specific namespace, the ns parameter to
nvme_user_cmd()/nvme_user_cmd64() is set. However, there is currently no
validation that the nsid specified in the passthru command targets the
namespace/nsid represented by the block device that the ioctl was
performed on.

Add a check that validates that the nsid in the passthru command matches
that of the supplied namespace.
Signed-off-by: NNiklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: NJavier González <javier@javigon.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NKanchan Joshi <joshi.k@samsung.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

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: 32acab31 ("nvme: implement multipath access to nvme subsystems")
Reported-by: NMartin George <marting@netapp.com>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Commit 8c4dfea9 ("nvme-fabrics: reject I/O to offline device")
introduced fast_io_fail_tmo but didn't export the value to sysfs. The
value can be set during the 'nvme connect'. Export the timeout value
to user space via sysfs to allow runtime configuration.

Cc: Victor Gladkov <Victor.Gladkov@kioxia.com>
Signed-off-by: NDaniel Wagner <dwagner@suse.de>
Reviewed-by: NEwan D. Milne <emilne@redhat.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NHimanshu Madhani <himanshu.madhaani@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

If there is an error we will leave the function early. So there
is no need for an else. Remove it.
Signed-off-by: NDaniel Wagner <dwagner@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

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: NChaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Signed-off-by: NDaniel Wagner <dwagner@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

SGLs support is mandatory for NVMe/FC, make sure that the target is
aligned to the specification.
Signed-off-by: NMax Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

SGLs support is mandatory for NVMe/tcp, make sure that the target is
aligned to the specification.
Signed-off-by: NMax Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Add 'idle_poll_period_usecs' option used by io_work() to support
network devices enabled with advanced interrupt moderation
supporting a relaxed interrupt model. It was discovered that
such a NIC used on the target was unable to support initiator
connection establishment, caused by the existing io_work()
flow that immediately exits after a loop with no activity and
does not re-queue itself.

With this new option a queue is assigned a period of time
that no activity must occur in order to become 'idle'.  Until
the queue is idle the work item is requeued.

The new module option is defined as changeable making it
flexible for testing purposes.

The pre-existing legacy behavior is preserved when no module option
for idle_poll_period_usecs is specified.
Signed-off-by: NMark Wunderlich <mark.wunderlich@intel.com>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

We are not changing anything in the TCP connection state so
we should not take a write_lock but rather a read lock.

This caused a deadlock when running nvmet-tcp and nvme-tcp
on the same system, where state_change callbacks on the
host and on the controller side have causal relationship
and made lockdep report on this with blktests:

================================
WARNING: inconsistent lock state
5.12.0-rc3 #1 Tainted: G          I
--------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-R} usage.
nvme/1324 [HC0[0]:SC0[0]:HE1:SE1] takes:
ffff888363151000 (clock-AF_INET){++-?}-{2:2}, at: nvme_tcp_state_change+0x21/0x150 [nvme_tcp]
{IN-SOFTIRQ-W} state was registered at:
  __lock_acquire+0x79b/0x18d0
  lock_acquire+0x1ca/0x480
  _raw_write_lock_bh+0x39/0x80
  nvmet_tcp_state_change+0x21/0x170 [nvmet_tcp]
  tcp_fin+0x2a8/0x780
  tcp_data_queue+0xf94/0x1f20
  tcp_rcv_established+0x6ba/0x1f00
  tcp_v4_do_rcv+0x502/0x760
  tcp_v4_rcv+0x257e/0x3430
  ip_protocol_deliver_rcu+0x69/0x6a0
  ip_local_deliver_finish+0x1e2/0x2f0
  ip_local_deliver+0x1a2/0x420
  ip_rcv+0x4fb/0x6b0
  __netif_receive_skb_one_core+0x162/0x1b0
  process_backlog+0x1ff/0x770
  __napi_poll.constprop.0+0xa9/0x5c0
  net_rx_action+0x7b3/0xb30
  __do_softirq+0x1f0/0x940
  do_softirq+0xa1/0xd0
  __local_bh_enable_ip+0xd8/0x100
  ip_finish_output2+0x6b7/0x18a0
  __ip_queue_xmit+0x706/0x1aa0
  __tcp_transmit_skb+0x2068/0x2e20
  tcp_write_xmit+0xc9e/0x2bb0
  __tcp_push_pending_frames+0x92/0x310
  inet_shutdown+0x158/0x300
  __nvme_tcp_stop_queue+0x36/0x270 [nvme_tcp]
  nvme_tcp_stop_queue+0x87/0xb0 [nvme_tcp]
  nvme_tcp_teardown_admin_queue+0x69/0xe0 [nvme_tcp]
  nvme_do_delete_ctrl+0x100/0x10c [nvme_core]
  nvme_sysfs_delete.cold+0x8/0xd [nvme_core]
  kernfs_fop_write_iter+0x2c7/0x460
  new_sync_write+0x36c/0x610
  vfs_write+0x5c0/0x870
  ksys_write+0xf9/0x1d0
  do_syscall_64+0x33/0x40
  entry_SYSCALL_64_after_hwframe+0x44/0xae
irq event stamp: 10687
hardirqs last  enabled at (10687): [<ffffffff9ec376bd>] _raw_spin_unlock_irqrestore+0x2d/0x40
hardirqs last disabled at (10686): [<ffffffff9ec374d8>] _raw_spin_lock_irqsave+0x68/0x90
softirqs last  enabled at (10684): [<ffffffff9f000608>] __do_softirq+0x608/0x940
softirqs last disabled at (10649): [<ffffffff9cdedd31>] do_softirq+0xa1/0xd0

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(clock-AF_INET);
  <Interrupt>
    lock(clock-AF_INET);

 *** DEADLOCK ***

5 locks held by nvme/1324:
 #0: ffff8884a01fe470 (sb_writers#4){.+.+}-{0:0}, at: ksys_write+0xf9/0x1d0
 #1: ffff8886e435c090 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x216/0x460
 #2: ffff888104d90c38 (kn->active#255){++++}-{0:0}, at: kernfs_remove_self+0x22d/0x330
 #3: ffff8884634538d0 (&queue->queue_lock){+.+.}-{3:3}, at: nvme_tcp_stop_queue+0x52/0xb0 [nvme_tcp]
 #4: ffff888363150d30 (sk_lock-AF_INET){+.+.}-{0:0}, at: inet_shutdown+0x59/0x300

stack backtrace:
CPU: 26 PID: 1324 Comm: nvme Tainted: G          I       5.12.0-rc3 #1
Hardware name: Dell Inc. PowerEdge R640/06NR82, BIOS 2.10.0 11/12/2020
Call Trace:
 dump_stack+0x93/0xc2
 mark_lock_irq.cold+0x2c/0xb3
 ? verify_lock_unused+0x390/0x390
 ? stack_trace_consume_entry+0x160/0x160
 ? lock_downgrade+0x100/0x100
 ? save_trace+0x88/0x5e0
 ? _raw_spin_unlock_irqrestore+0x2d/0x40
 mark_lock+0x530/0x1470
 ? mark_lock_irq+0x1d10/0x1d10
 ? enqueue_timer+0x660/0x660
 mark_usage+0x215/0x2a0
 __lock_acquire+0x79b/0x18d0
 ? tcp_schedule_loss_probe.part.0+0x38c/0x520
 lock_acquire+0x1ca/0x480
 ? nvme_tcp_state_change+0x21/0x150 [nvme_tcp]
 ? rcu_read_unlock+0x40/0x40
 ? tcp_mtu_probe+0x1ae0/0x1ae0
 ? kmalloc_reserve+0xa0/0xa0
 ? sysfs_file_ops+0x170/0x170
 _raw_read_lock+0x3d/0xa0
 ? nvme_tcp_state_change+0x21/0x150 [nvme_tcp]
 nvme_tcp_state_change+0x21/0x150 [nvme_tcp]
 ? sysfs_file_ops+0x170/0x170
 inet_shutdown+0x189/0x300
 __nvme_tcp_stop_queue+0x36/0x270 [nvme_tcp]
 nvme_tcp_stop_queue+0x87/0xb0 [nvme_tcp]
 nvme_tcp_teardown_admin_queue+0x69/0xe0 [nvme_tcp]
 nvme_do_delete_ctrl+0x100/0x10c [nvme_core]
 nvme_sysfs_delete.cold+0x8/0xd [nvme_core]
 kernfs_fop_write_iter+0x2c7/0x460
 new_sync_write+0x36c/0x610
 ? new_sync_read+0x600/0x600
 ? lock_acquire+0x1ca/0x480
 ? rcu_read_unlock+0x40/0x40
 ? lock_is_held_type+0x9a/0x110
 vfs_write+0x5c0/0x870
 ksys_write+0xf9/0x1d0
 ? __ia32_sys_read+0xa0/0xa0
 ? lockdep_hardirqs_on_prepare.part.0+0x198/0x340
 ? syscall_enter_from_user_mode+0x27/0x70
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 872d26a3 ("nvmet-tcp: add NVMe over TCP target driver")
Reported-by: NYi Zhang <yi.zhang@redhat.com>
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The TCP stack can run from process context for a long time
so we should disable BH here.

Fixes: 3f2304f8 ("nvme-tcp: add NVMe over TCP host driver")
Signed-off-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Return NVME_SC_INVALID_FIELD from discovery controller like normal
controller when executing identify or get log page command.
Signed-off-by: NHou Pu <houpu.main@gmail.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

We don't need to repeatedly spam the kernel logs with the same warning
about unhandled passthrough IO effects. Just one warning is sufficient
to observe this condition occurs.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

All nvme transport drivers preallocate an nvme command for each request.
Assume to use that command for nvme_setup_cmd() instead of requiring
drivers pass a pointer to it. All nvme drivers must initialize the
generic nvme_request 'cmd' to point to the transport's preallocated
nvme_command.

The generic nvme_request cmd pointer had previously been used only as a
temporary copy for passthrough commands. Since it now points to the
command that gets dispatched, passthrough commands must directly set it
up prior to executing the request.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Except for pci, all the nvme transport drivers allocate a command within
the driver's pdu. Align pci with everyone else by allocating the nvme
command within pci's pdu and replace the .queue_rq() stack variable with
this.
Signed-off-by: NKeith Busch <kbusch@kernel.org>
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NHimanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

According to the NVM specifications, the model number size should be
40 bytes (bytes 63:24 of the Identify Controller data structure).
Therefore, any attempt to store a value into model_number which
exceeds 40 bytes should return an error.
Reviewed-by: NMax Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: NNoam Gottlieb <ngottlieb@nvidia.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The function nvmet_ctrl_find_get() accepts out pointer to nvmet_ctrl
structure. This function returns the same error value from two places
that is :- NVME_SC_CONNECT_INVALID_PARAM | NVME_SC_DNR.

Move this to the caller so we can change the return type to nvmet_ctrl.

Now that we can changed the return type, instead of taking out pointer
to the nvmet_ctrl structure remove that function parameter and return
the valid nvmet_ctrl pointer on success and NULL on failure.

Also, add and rename the goto labels for more readability with comments.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Add minimum description of the hosthandle parameter for
nvmet_fc_rcv_ls_req() so that we can get rid of the following warning.

drivers/nvme//target/fc.c:2009: warning: Function parameter or member 'hosthandle' not described in 'nvmet_fc_rcv_ls_req
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NJames Smart <jsmart2021@gmail.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The nvme_fc_rcv_ls_req() function has first argument as pointer to
remoteport named portprt, but in the documentation comment that is name
is used as remoteport. Fix that to get rid if the compilation warning.

drivers/nvme//host/fc.c:1724: warning: Function parameter or member 'portptr' not described in 'nvme_fc_rcv_ls_req'
drivers/nvme//host/fc.c:1724: warning: Excess function parameter 'remoteport' description in 'nvme_fc_rcv_ls_req'
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: NJames Smart <jsmart2021@gmail.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Add a new line in functions nvme_pr_preempt(), nvme_pr_clear(), and
nvme_pr_release() after variable declaration which follows the rest of
the code in the nvme/host/core.c.

No functional change(s) in this patch.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

nvme_clear_request() has a check for flag REQ_DONTPREP and it is called
from nvme_init_request() and nvme_setuo_cmd().

The function nvme_init_request() is called from nvme_alloc_request()
and nvme_alloc_request_qid(). From these two callers new request is
allocated everytime. For newly allocated request RQF_DONTPREP is never
set. Since after getting a tag, block layer sets the req->rq_flags == 0
and never sets the REQ_DONTPREP when returning the request :-

nvme_alloc_request()
	blk_mq_alloc_request()
		blk_mq_rq_ctx_init()
			rq->rq_flags = 0 <----

nvme_alloc_request_qid()
	blk_mq_alloc_request_hctx()
		blk_mq_rq_ctx_init()
			rq->rq_flags = 0 <----

The block layer does set req->rq_flags but REQ_DONTPREP is not one of
them and that is set by the driver.

That means we can unconditinally set the REQ_DONTPREP value to the
rq->rq_flags when nvme_init_request()->nvme_clear_request() is called
from above two callers.

Move the check for REQ_DONTPREP from nvme_clear_nvme_request() into
nvme_setup_cmd().

This is needed since nvme_alloc_request() now gets called from fast
path when NVMeOF target is configured with passthru backend to avoid
unnecessary checks in the fast path.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Since nvmet_setup_passthru() function falls in fast path when called
from the NVMeOF passthru backend, make it inline.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The function nvme_init_ctrl_finish() (formerly nvme_init_identify()) has
grown over the period of time about ~200 lines given the size of nvme id
ctrl data structure.

Move the nvme_id_ctrl data structure related initilzation into helper
nvme_init_identify() and call it from nvme_init_ctrl_finish().

When we move the code into nvme_init_identify() change the local
variable i from int to unsigned int and remove the duplicate kfree()
after nvme_mpath_init() and jump to the label out_free if
nvme_mpath_ini() fails.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

This is a prep patch so that we can move the identify data structure
related code initialization from nvme_init_identify() into a helper.

Rename the function nvmet_init_identify() to nvmet_init_ctrl_finish().

Next patch will move the nvme_id_ctrl related initialization from newly
renamed function nvme_init_ctrl_finish() into the nvme_init_identify()
helper.
Signed-off-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

For passthrough I/O commands, effects are usually to be zero.
nvme_passthrough_end() does three checks in futility for this case.
Bail out of function-call/checks.
Signed-off-by: NKanchan Joshi <joshi.k@samsung.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Use the proper macro instead of hard-coded value.
Signed-off-by: NKanchan Joshi <joshi.k@samsung.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>