Qemu unconditionally reports a UUID, which depending on the qemu version
is either all-null (which is incorrect but harmless) or contains a single
bit set for all controllers.  In addition it can also optionally report
a eui64 which needs to be manually set.  Disable namespace identifiers
for Qemu controlles entirely even if in some cases they could be set
correctly through manual intervention.

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

The MAXIO MAP1002/1202 controllers reports completely bogus Namespace
identifiers that even change after suspend cycles.  Disable using
the Identifiers entirely.

Reported-by: 金韬 <me@kingtous.cn>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Tested-by: 金韬 <me@kingtous.cn>

Add a quirk to disable using and exporting namespace identifiers for
controllers where they are broken beyond repair.

The most directly visible problem with non-unique namespace identifiers
is that they break the /dev/disk/by-id/ links, with the link for a
supposedly unique identifier now pointing to one of multiple possible
namespaces that share the same ID, and a somewhat random selection of
which one actually shows up.

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>

Use the RQF_QUIET flag to skip the newly added verbose error reporting,
and set the flag in __nvme_submit_sync_cmd, which is used for most
internal passthrough requests where we do expect errors (e.g. due to
probing for optional functionality).  This is similar to what the SCSI
verbose error logging does.

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Alan Adamson <alan.adamson@oracle.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Tested-by: Alan Adamson <alan.adamson@oracle.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Pull block driver fixes from Jens Axboe:
 "Followup block driver updates and fixes for the 5.18-rc1 merge window.
  In detail:

   - NVMe pull request
       - Fix multipath hang when disk goes live over reconnect (Anton
         Eidelman)
       - fix RCU hole that allowed for endless looping in multipath
         round robin (Chris Leech)
       - remove redundant assignment after left shift (Colin Ian King)
       - add quirks for Samsung X5 SSDs (Monish Kumar R)
       - fix the read-only state for zoned namespaces with unsupposed
         features (Pankaj Raghav)
       - use a private workqueue instead of the system workqueue in
         nvmet (Sagi Grimberg)
       - allow duplicate NSIDs for private namespaces (Sungup Moon)
       - expose use_threaded_interrupts read-only in sysfs (Xin Hao)"

   - nbd minor allocation fix (Zhang)

   - drbd fixes and maintainer addition (Lars, Jakob, Christoph)

   - n64cart build fix (Jackie)

   - loop compat ioctl fix (Carlos)

   - misc fixes (Colin, Dongli)"

* tag 'for-5.18/drivers-2022-04-01' of git://git.kernel.dk/linux-block:
  drbd: remove check of list iterator against head past the loop body
  drbd: remove usage of list iterator variable after loop
  nbd: fix possible overflow on 'first_minor' in nbd_dev_add()
  MAINTAINERS: add drbd co-maintainer
  drbd: fix potential silent data corruption
  loop: fix ioctl calls using compat_loop_info
  nvme-multipath: fix hang when disk goes live over reconnect
  nvme: fix RCU hole that allowed for endless looping in multipath round robin
  nvme: allow duplicate NSIDs for private namespaces
  nvmet: remove redundant assignment after left shift
  nvmet: use a private workqueue instead of the system workqueue
  nvme-pci: add quirks for Samsung X5 SSDs
  nvme-pci: expose use_threaded_interrupts read-only in sysfs
  nvme: fix the read-only state for zoned namespaces with unsupposed features
  n64cart: convert bi_disk to bi_bdev->bd_disk fix build
  xen/blkfront: fix comment for need_copy
  xen-blkback: remove redundant assignment to variable i

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>

Make nvme_ns_remove match the assumptions elsewhere.

1) !NVME_NS_READY needs to be srcu synchronized to make sure nothing is
   running in __nvme_find_path or nvme_round_robin_path that will
   re-assign this ns to current_path.

2) Any matching current_path entries need to be cleared before removing
   from the siblings list, to prevent calling nvme_round_robin_path with
   an "old" ns that's off list.

3) Finally the list_del_rcu can happen, and then synchronize again
   before releasing any reference counts.

Signed-off-by: Christoph Hellwig <hch@lst.de>

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>

The left shift is followed by a re-assignment back to cc_css, the
assignment is redundant.  Fix this by replacing the "<<=" operator with
"<<" instead.

This cleans up the clang scan build warning:

drivers/nvme/target/core.c:1124:10: warning: Although the value stored to 'cc_css' is used in the enclosing expression, the value is never actually read from 'cc_css' [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-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>

Any attempt to flush kernel-global WQs has possibility of deadlock
so we should simply stop using them, instead introduce nvmet_wq
which is the generic nvmet workqueue for work elements that
don't explicitly require a dedicated workqueue (by the mere fact
that they are using the system_wq).

Changes were done using the following replaces:

 - s/schedule_work(/queue_work(nvmet_wq, /g
 - s/schedule_delayed_work(/queue_delayed_work(nvmet_wq, /g
 - s/flush_scheduled_work()/flush_workqueue(nvmet_wq)/g

Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>