We want to guarantee that we have chap buffers when a controller
reconnects under memory pressure. Add a mempool specifically
for that.
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

dhchap structure is per-queue, it is wasteful to keep it for the entire
lifetime of the queue. Allocate it dynamically and get rid of it after
authentication. We don't need kzalloc because all accessors are clearing
it before writing to it.

Also, remove redundant chap buf_size which is always 4096, use a define
instead.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

No one passes NVME_QID_ANY to nvme_auth_negotiate.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Replace ctrl ctrl_key/host_key only after nvme_auth_generate_key is successful.
Also, this fixes a bug where the keys are leaked.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme_auth_generate_key can fail, don't ignore it upon initialization.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

host_response, host_key, ctrl_key and sess_key are
freed in nvme_auth_reset_dhchap which is called from
nvme_auth_free_dhchap.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

The connect sequence will re-authenticate.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Only the nvme module calls it.
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Use nvme_ctrl_auth_work and nvme_queue_auth_work for better
readability.
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme_auth_[reset|free] operate on the controller while
__nvme_auth_[reset|free] operate on a chap struct (which maps to a queue
context). Rename it for clarity.
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Unbind a device driver when a reset fails is very unusual behavior.
Just shut the controller down and leave it in dead state if we fail
to reset it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

nvme_reset_work is a little fragile as it needs to handle both resetting
a live controller and initializing one during probe.  Split out the initial
probe and open code it in nvme_probe and leave nvme_reset_work to just do
the live controller reset.

This fixes a recently introduced bug where nvme_dev_disable causes a NULL
pointer dereferences in blk_mq_quiesce_tagset because the tagset pointer
is not set when the reset state is entered directly from the new state.
The separate probe code can skip the reset state and probe directly and
fixes this.

To make sure the system isn't single threaded on enabling nvme
controllers, set the PROBE_PREFER_ASYNCHRONOUS flag in the device_driver
structure so that the driver core probes in parallel.

Fixes: 98d81f0d ("nvme: use blk_mq_[un]quiesce_tagset")
Reported-by: Gerd Bayer <gbayer@linux.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Tested-by Gerd Bayer <gbayer@linxu.ibm.com>

Check that a HMB is wanted into the allocation helper instead of the
caller.  This makes life simpler for an upcoming second caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

Move the OACS check and the error checking into nvme_dbbuf_dma_alloc so
that an upcoming second caller doesn't have to duplicate this boilerplate
code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

nvme_pci_configure_admin_queue is called right after nvme_pci_enable, and
it's work is undone by nvme_dev_disable.
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>
Tested-by Gerd Bayer <gbayer@linxu.ibm.com>

Move setting of low-level constant parameters from nvme_reset_work to
nvme_pci_alloc_ctrl.
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>
Tested-by Gerd Bayer <gbayer@linxu.ibm.com>

Add a helper that allocates the nvme_dev structure up to the point where
we can call nvme_init_ctrl.  This pairs with the free_ctrl method and can
thus be used to cleanup the teardown path and make it more symmetric.

Note that this now calls nvme_init_ctrl a lot earlier during probing,
which also means the per-controller character device shows up earlier.
Due to the controller state no commnds can be send on it, but it might
make sense to delay the cdev registration until nvme_init_ctrl_finish.
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>
Tested-by Gerd Bayer <gbayer@linxu.ibm.com>

Add a helper to create the iod mempool.
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>
Tested-by Gerd Bayer <gbayer@linxu.ibm.com>

nvme_dbbuf_dma_free frees dma coherent memory, so it must not be called
after ->remove has returned.  Fortunately there is no way to use it
after shutdown as no more I/O is possible so it can be moved.  Similarly
the iod_mempool can't be used for a device kept alive after shutdown, so
move it next to freeing the PRP pools.
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>
Tested-by Gerd Bayer <gbayer@linxu.ibm.com>

Once the controller is shutdown no one can access the admin queue.  Tear
it down in nvme_dev_remove_admin, which matches the flow in the other
drivers.
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>
Tested-by Gerd Bayer <gbayer@linxu.ibm.com>

Allow the transport driver to override the attribute groups for the
control device, so that the PCIe driver doesn't manually have to add a
group after device creation and keep track of it.
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>
Tested-by Gerd Bayer <gbayer@linxu.ibm.com>

Nothing about the TCG Opal support is PCIe transport specific, so move it
to the core code.  For this nvme_init_ctrl_finish grows a new
was_suspended argument that allows the transport driver to tell the OPAL
code if the controller came out of a suspend cycle.
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>
Reviewed-by: James Smart <jsmart2021@gmail.com>
Tested-by Gerd Bayer <gbayer@linxu.ibm.com>

nvme_passthrough_end can race with a reset, which can lead to
racing stores to the cels xarray as well as further shengians
with upcoming more complicated initialization.

So drop the call and just log that the controller capabilities
might have changed and a reset could be required to use the new
controller capabilities.
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>
Tested-by Gerd Bayer <gbayer@linxu.ibm.com>

While the specification allows devices to either deallocate data
or to actually write zeroes on any Write Zeroes command, many SSDs
only do the sensible thing and deallocate data when the DEAC bit
is specific.  Set it when it is supported and the caller doesn't
explicitly opt out of deallocation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

Allow all identify-namespace variants (CNS 00h, 05h and 08h) without
requiring CAP_SYS_ADMIN. The information (retrieved using id-ns) is
needed to form IO commands for passthrough interface.
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Currently both io and admin commands are kept under a
coarse-granular CAP_SYS_ADMIN check, disregarding file mode completely.

$ ls -l /dev/ng*
crw-rw-rw- 1 root root 242, 0 Sep  9 19:20 /dev/ng0n1
crw------- 1 root root 242, 1 Sep  9 19:20 /dev/ng0n2

In the example above, ng0n1 appears as if it may allow unprivileged
read/write operation but it does not and behaves same as ng0n2.

This patch implements a shift from CAP_SYS_ADMIN to more fine-granular
control for io-commands.
If CAP_SYS_ADMIN is present, nothing else is checked as before.
Otherwise, following rules are in place
- any admin-cmd is not allowed
- vendor-specific and fabric commmand are not allowed
- io-commands that can write are allowed if matching FMODE_WRITE
permission is present
- io-commands that read are allowed

Add a helper nvme_cmd_allowed that implements above policy.
Change all the callers of CAP_SYS_ADMIN to go through nvme_cmd_allowed
for any decision making.
Since file open mode is counted for any approval/denial, change at
various places to keep file-mode information handy.
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

sizeof( struct nvmefc_ls_rcv_op ) = 64
sizeof( union nvmefc_ls_requests ) = 1024
sizeof( union nvmefc_ls_responses ) = 128

So, in nvme_fc_rcv_ls_req(), 1216 bytes of memory are requested when
kzalloc() is called.

Because of the way memory allocations are performed, 2048 bytes are
allocated. So about 800 bytes are wasted for each request.

Switch to 3 distinct memory allocations, in order to:
   - save these 800 bytes
   - avoid zeroing this extra memory
   - make sure that memory is properly aligned in case of DMA access
    ("fc_dma_map_single(lsop->rspbuf)" just a few lines below)
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

There is no need to have a separate slab cache for each namespace,
and having separate ones creates duplicate debugs file names as well.

Fixes: d5eff33e ("nvmet: add simple file backed ns support")
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>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

In order to test queue number changes we need to make sure that the
host reconnects. Because only when the host disconnects from the
target the number of queues are allowed to change according the spec.

The initial idea was to disable and re-enable the ports and have the
host wait until the KATO timer expires, triggering error
recovery. Though the host would see a DNR reply when trying to
reconnect. Because of the DNR bit the connection is dropped
completely. There is no point in trying to reconnect with the same
parameters according the spec.

We can force to reconnect the host is by deleting all controllers. The
host will observe any newly posted request to fail and thus starts the
error recovery but this time without the DNR bit set.
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Chaitanya Kulkarni  <kch@nvidia.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
nvmet_update_sq_head.  x86 CMPXCHG instruction returns success in ZF flag, so
this change saves a compare after cmpxchg (and related move instruction in
front of cmpxchg).

Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails. There is no need to re-read the value in the loop.

Note that the value from *ptr should be read using READ_ONCE to prevent
the compiler from merging, refetching or reordering the read.

No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Merge branch 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into for-6.2/block

Pull MD fixes from Song.

* 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md/raid1: stop mdx_raid1 thread when raid1 array run failed
  md/raid5: use bdev_write_cache instead of open coding it
  md: fix a crash in mempool_free
  md/raid0, raid10: Don't set discard sectors for request queue
  md/bitmap: Fix bitmap chunk size overflow issues
  md: introduce md_ro_state
  md: factor out __md_set_array_info()
  lib/raid6: drop RAID6_USE_EMPTY_ZERO_PAGE
  raid5-cache: use try_cmpxchg in r5l_wake_reclaim
  drivers/md/md-bitmap: check the return value of md_bitmap_get_counter()

fail run raid1 array when we assemble array with the inactive disk only,
but the mdx_raid1 thread were not stop, Even if the associated resources
have been released. it will caused a NULL dereference when we do poweroff.

This causes the following Oops:
    [  287.587787] BUG: kernel NULL pointer dereference, address: 0000000000000070
    [  287.594762] #PF: supervisor read access in kernel mode
    [  287.599912] #PF: error_code(0x0000) - not-present page
    [  287.605061] PGD 0 P4D 0
    [  287.607612] Oops: 0000 [#1] SMP NOPTI
    [  287.611287] CPU: 3 PID: 5265 Comm: md0_raid1 Tainted: G     U            5.10.146 #0
    [  287.619029] Hardware name: xxxxxxx/To be filled by O.E.M, BIOS 5.19 06/16/2022
    [  287.626775] RIP: 0010:md_check_recovery+0x57/0x500 [md_mod]
    [  287.632357] Code: fe 01 00 00 48 83 bb 10 03 00 00 00 74 08 48 89 ......
    [  287.651118] RSP: 0018:ffffc90000433d78 EFLAGS: 00010202
    [  287.656347] RAX: 0000000000000000 RBX: ffff888105986800 RCX: 0000000000000000
    [  287.663491] RDX: ffffc90000433bb0 RSI: 00000000ffffefff RDI: ffff888105986800
    [  287.670634] RBP: ffffc90000433da0 R08: 0000000000000000 R09: c0000000ffffefff
    [  287.677771] R10: 0000000000000001 R11: ffffc90000433ba8 R12: ffff888105986800
    [  287.684907] R13: 0000000000000000 R14: fffffffffffffe00 R15: ffff888100b6b500
    [  287.692052] FS:  0000000000000000(0000) GS:ffff888277f80000(0000) knlGS:0000000000000000
    [  287.700149] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [  287.705897] CR2: 0000000000000070 CR3: 000000000320a000 CR4: 0000000000350ee0
    [  287.713033] Call Trace:
    [  287.715498]  raid1d+0x6c/0xbbb [raid1]
    [  287.719256]  ? __schedule+0x1ff/0x760
    [  287.722930]  ? schedule+0x3b/0xb0
    [  287.726260]  ? schedule_timeout+0x1ed/0x290
    [  287.730456]  ? __switch_to+0x11f/0x400
    [  287.734219]  md_thread+0xe9/0x140 [md_mod]
    [  287.738328]  ? md_thread+0xe9/0x140 [md_mod]
    [  287.742601]  ? wait_woken+0x80/0x80
    [  287.746097]  ? md_register_thread+0xe0/0xe0 [md_mod]
    [  287.751064]  kthread+0x11a/0x140
    [  287.754300]  ? kthread_park+0x90/0x90
    [  287.757974]  ret_from_fork+0x1f/0x30

In fact, when raid1 array run fail, we need to do
md_unregister_thread() before raid1_free().
Signed-off-by: Jiang Li <jiang.li@ugreen.com>
Signed-off-by: Song Liu <song@kernel.org>

Use the bdev_write_cache instead of two equivalent open coded checks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>

There's a crash in mempool_free when running the lvm test
shell/lvchange-rebuild-raid.sh.

The reason for the crash is this:
* super_written calls atomic_dec_and_test(&mddev->pending_writes) and
  wake_up(&mddev->sb_wait). Then it calls rdev_dec_pending(rdev, mddev)
  and bio_put(bio).
* so, the process that waited on sb_wait and that is woken up is racing
  with bio_put(bio).
* if the process wins the race, it calls bioset_exit before bio_put(bio)
  is executed.
* bio_put(bio) attempts to free a bio into a destroyed bio set - causing
  a crash in mempool_free.

We fix this bug by moving bio_put before atomic_dec_and_test.

We also move rdev_dec_pending before atomic_dec_and_test as suggested by
Neil Brown.

The function md_end_flush has a similar bug - we must call bio_put before
we decrement the number of in-progress bios.

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 #PF: supervisor write access in kernel mode
 #PF: error_code(0x0002) - not-present page
 PGD 11557f0067 P4D 11557f0067 PUD 0
 Oops: 0002 [#1] PREEMPT SMP
 CPU: 0 PID: 73 Comm: kworker/0:1 Not tainted 6.1.0-rc3 #5
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
 Workqueue: kdelayd flush_expired_bios [dm_delay]
 RIP: 0010:mempool_free+0x47/0x80
 Code: 48 89 ef 5b 5d ff e0 f3 c3 48 89 f7 e8 32 45 3f 00 48 63 53 08 48 89 c6 3b 53 04 7d 2d 48 8b 43 10 8d 4a 01 48 89 df 89 4b 08 <48> 89 2c d0 e8 b0 45 3f 00 48 8d 7b 30 5b 5d 31 c9 ba 01 00 00 00
 RSP: 0018:ffff88910036bda8 EFLAGS: 00010093
 RAX: 0000000000000000 RBX: ffff8891037b65d8 RCX: 0000000000000001
 RDX: 0000000000000000 RSI: 0000000000000202 RDI: ffff8891037b65d8
 RBP: ffff8891447ba240 R08: 0000000000012908 R09: 00000000003d0900
 R10: 0000000000000000 R11: 0000000000173544 R12: ffff889101a14000
 R13: ffff8891562ac300 R14: ffff889102b41440 R15: ffffe8ffffa00d05
 FS:  0000000000000000(0000) GS:ffff88942fa00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000000 CR3: 0000001102e99000 CR4: 00000000000006b0
 Call Trace:
  <TASK>
  clone_endio+0xf4/0x1c0 [dm_mod]
  clone_endio+0xf4/0x1c0 [dm_mod]
  __submit_bio+0x76/0x120
  submit_bio_noacct_nocheck+0xb6/0x2a0
  flush_expired_bios+0x28/0x2f [dm_delay]
  process_one_work+0x1b4/0x300
  worker_thread+0x45/0x3e0
  ? rescuer_thread+0x380/0x380
  kthread+0xc2/0x100
  ? kthread_complete_and_exit+0x20/0x20
  ret_from_fork+0x1f/0x30
  </TASK>
 Modules linked in: brd dm_delay dm_raid dm_mod af_packet uvesafb cfbfillrect cfbimgblt cn cfbcopyarea fb font fbdev tun autofs4 binfmt_misc configfs ipv6 virtio_rng virtio_balloon rng_core virtio_net pcspkr net_failover failover qemu_fw_cfg button mousedev raid10 raid456 libcrc32c async_raid6_recov async_memcpy async_pq raid6_pq async_xor xor async_tx raid1 raid0 md_mod sd_mod t10_pi crc64_rocksoft crc64 virtio_scsi scsi_mod evdev psmouse bsg scsi_common [last unloaded: brd]
 CR2: 0000000000000000
 ---[ end trace 0000000000000000 ]---
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Song Liu <song@kernel.org>

It should use disk_stack_limits to get a proper max_discard_sectors
rather than setting a value by stack drivers.

And there is a bug. If all member disks are rotational devices,
raid0/raid10 set max_discard_sectors. So the member devices are
not ssd/nvme, but raid0/raid10 export the wrong value. It reports
warning messages in function __blkdev_issue_discard when mkfs.xfs
like this:

[ 4616.022599] ------------[ cut here ]------------
[ 4616.027779] WARNING: CPU: 4 PID: 99634 at block/blk-lib.c:50 __blkdev_issue_discard+0x16a/0x1a0
[ 4616.140663] RIP: 0010:__blkdev_issue_discard+0x16a/0x1a0
[ 4616.146601] Code: 24 4c 89 20 31 c0 e9 fe fe ff ff c1 e8 09 8d 48 ff 4c 89 f0 4c 09 e8 48 85 c1 0f 84 55 ff ff ff b8 ea ff ff ff e9 df fe ff ff <0f> 0b 48 8d 74 24 08 e8 ea d6 00 00 48 c7 c6 20 1e 89 ab 48 c7 c7
[ 4616.167567] RSP: 0018:ffffaab88cbffca8 EFLAGS: 00010246
[ 4616.173406] RAX: ffff9ba1f9e44678 RBX: 0000000000000000 RCX: ffff9ba1c9792080
[ 4616.181376] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9ba1c9792080
[ 4616.189345] RBP: 0000000000000cc0 R08: ffffaab88cbffd10 R09: 0000000000000000
[ 4616.197317] R10: 0000000000000012 R11: 0000000000000000 R12: 0000000000000000
[ 4616.205288] R13: 0000000000400000 R14: 0000000000000cc0 R15: ffff9ba1c9792080
[ 4616.213259] FS:  00007f9a5534e980(0000) GS:ffff9ba1b7c80000(0000) knlGS:0000000000000000
[ 4616.222298] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4616.228719] CR2: 000055a390a4c518 CR3: 0000000123e40006 CR4: 00000000001706e0
[ 4616.236689] Call Trace:
[ 4616.239428]  blkdev_issue_discard+0x52/0xb0
[ 4616.244108]  blkdev_common_ioctl+0x43c/0xa00
[ 4616.248883]  blkdev_ioctl+0x116/0x280
[ 4616.252977]  __x64_sys_ioctl+0x8a/0xc0
[ 4616.257163]  do_syscall_64+0x5c/0x90
[ 4616.261164]  ? handle_mm_fault+0xc5/0x2a0
[ 4616.265652]  ? do_user_addr_fault+0x1d8/0x690
[ 4616.270527]  ? do_syscall_64+0x69/0x90
[ 4616.274717]  ? exc_page_fault+0x62/0x150
[ 4616.279097]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 4616.284748] RIP: 0033:0x7f9a55398c6b
Signed-off-by: Xiao Ni <xni@redhat.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Song Liu <song@kernel.org>

- limit bitmap chunk size internal u64 variable to values not overflowing
  the u32 bitmap superblock structure variable stored on persistent media
- assign bitmap chunk size internal u64 variable from unsigned values to
  avoid possible sign extension artifacts when assigning from a s32 value

The bug has been there since at least kernel 4.0.
Steps to reproduce it:
1: mdadm -C /dev/mdx -l 1 --bitmap=internal --bitmap-chunk=256M -e 1.2
-n2 /dev/rnbd1 /dev/rnbd2
2 resize member device rnbd1 and rnbd2 to 8 TB
3 mdadm --grow /dev/mdx --size=max

The bitmap_chunksize will overflow without patch.

Cc: stable@vger.kernel.org
Signed-off-by: Florian-Ewald Mueller <florian-ewald.mueller@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Song Liu <song@kernel.org>

Introduce md_ro_state for mddev->ro, so it is easy to understand.
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>

Factor out __md_set_array_info(). No functional change.
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Song Liu <song@kernel.org>

RAID6_USE_EMPTY_ZERO_PAGE is unused and hardcoded to 0, so let's drop it.
Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>

Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
r5l_wake_reclaim. 86 CMPXCHG instruction returns success in ZF flag, so
this change saves a compare after cmpxchg (and related move instruction in
front of cmpxchg).

Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails. There is no need to re-read the value in the loop.

Note that the value from *ptr should be read using READ_ONCE to prevent
the compiler from merging, refetching or reordering the read.

No functional change intended.

Cc: Song Liu <song@kernel.org>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Song Liu <song@kernel.org>