async_xor: increase src_offs when dropping destination page

Now we support sharing one page if PAGE_SIZE is not equal stripe size. To
support this, it needs to support calculating xor value with different
offsets for each r5dev. One offset array is used to record those offsets.

In RMW mode, parity page is used as a source page. It sets
ASYNC_TX_XOR_DROP_DST before calculating xor value in ops_run_prexor5.
So it needs to add src_list and src_offs at the same time. Now it only
needs src_list. So the xor value which is calculated is wrong. It can
cause data corruption problem.

I can reproduce this problem 100% on a POWER8 machine. The steps are:

  mdadm -CR /dev/md0 -l5 -n3 /dev/sdb1 /dev/sdc1 /dev/sdd1 --size=3G
  mkfs.xfs /dev/md0
  mount /dev/md0 /mnt/test
  mount: /mnt/test: mount(2) system call failed: Structure needs cleaning.

Fixes: 29bcff787a25 ("md/raid5: add new xor function to support different page offset")
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Song Liu <song@kernel.org>

drivers/block/null_blk/main: Fix a double free in null_init.

In null_init, null_add_dev(dev) is called.
In null_add_dev, it calls null_free_zoned_dev(dev) to free dev->zones
via kvfree(dev->zones) in out_cleanup_zone branch and returns err.
Then null_init accept the err code and then calls null_free_dev(dev).

But in null_free_dev(dev), dev->zones is freed again by
null_free_zoned_dev().

My patch set dev->zones to NULL in null_free_zoned_dev() after
kvfree(dev->zones) is called, to avoid the double free.

Fixes: 2984c8684f962 ("nullb: factor disk parameters")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Link: https://lore.kernel.org/r/20210426143229.7374-1-lyl2019@mail.ustc.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Merge branch 'md-next' of https://git./linux/kernel/git/song/md into for-5.13/drivers

Pull MD fixes from Song.

* 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md/raid1: properly indicate failure when ending a failed write request
  md-cluster: fix use-after-free issue when removing rdev

md/raid1: properly indicate failure when ending a failed write request

This patch addresses a data corruption bug in raid1 arrays using bitmaps.
Without this fix, the bitmap bits for the failed I/O end up being cleared.

Since we are in the failure leg of raid1_end_write_request, the request
either needs to be retried (R1BIO_WriteError) or failed (R1BIO_Degraded).

Fixes: eeba6809d8d5 ("md/raid1: end bio when the device faulty")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Paul Clements <paul.clements@us.sios.com>
Signed-off-by: Song Liu <song@kernel.org>

md-cluster: fix use-after-free issue when removing rdev

md_kick_rdev_from_array will remove rdev, so we should
use rdev_for_each_safe to search list.

How to trigger:

env: Two nodes on kvm-qemu x86_64 VMs (2C2G with 2 iscsi luns).

```
node2=192.168.0.3

for i in {1..20}; do
    echo ==== $i `date` ====;

    mdadm -Ss && ssh ${node2} "mdadm -Ss"
    wipefs -a /dev/sda /dev/sdb

    mdadm -CR /dev/md0 -b clustered -e 1.2 -n 2 -l 1 /dev/sda \
       /dev/sdb --assume-clean
    ssh ${node2} "mdadm -A /dev/md0 /dev/sda /dev/sdb"
    mdadm --wait /dev/md0
    ssh ${node2} "mdadm --wait /dev/md0"

    mdadm --manage /dev/md0 --fail /dev/sda --remove /dev/sda
    sleep 1
done
```

Crash stack:

```
stack segment: 0000 [#1] SMP
... ...
RIP: 0010:md_check_recovery+0x1e8/0x570 [md_mod]
... ...
RSP: 0018:ffffb149807a7d68 EFLAGS: 00010207
RAX: 0000000000000000 RBX: ffff9d494c180800 RCX: ffff9d490fc01e50
RDX: fffff047c0ed8308 RSI: 0000000000000246 RDI: 0000000000000246
RBP: 6b6b6b6b6b6b6b6b R08: ffff9d490fc01e40 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: ffff9d494c180818 R14: ffff9d493399ef38 R15: ffff9d4933a1d800
FS:  0000000000000000(0000) GS:ffff9d494f700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe68cab9010 CR3: 000000004c6be001 CR4: 00000000003706e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 raid1d+0x5c/0xd40 [raid1]
 ? finish_task_switch+0x75/0x2a0
 ? lock_timer_base+0x67/0x80
 ? try_to_del_timer_sync+0x4d/0x80
 ? del_timer_sync+0x41/0x50
 ? schedule_timeout+0x254/0x2d0
 ? md_start_sync+0xe0/0xe0 [md_mod]
 ? md_thread+0x127/0x160 [md_mod]
 md_thread+0x127/0x160 [md_mod]
 ? wait_woken+0x80/0x80
 kthread+0x10d/0x130
 ? kthread_park+0xa0/0xa0
 ret_from_fork+0x1f/0x40
```

Fixes: dbb64f8635f5d ("md-cluster: Fix adding of new disk with new reload code")
Fixes: 659b254fa7392 ("md-cluster: remove a disk asynchronously from cluster environment")
Cc: stable@vger.kernel.org
Reviewed-by: Gang He <ghe@suse.com>
Signed-off-by: Heming Zhao <heming.zhao@suse.com>
Signed-off-by: Song Liu <song@kernel.org>

Merge tag 'nvme-5.13-2021-04-22' of git://git.infradead.org/nvme into for-5.13/drivers

Pull NVMe updates from Christoph:

"- add support for a per-namespace character device (Minwoo Im)
 - various KATO fixes and cleanups (Hou Pu, Hannes Reinecke)
 - APST fix and cleanup"

* tag 'nvme-5.13-2021-04-22' of git://git.infradead.org/nvme:
  nvme: introduce generic per-namespace chardev
  nvme: cleanup nvme_configure_apst
  nvme: do not try to reconfigure APST when the controller is not live
  nvme: add 'kato' sysfs attribute
  nvme: sanitize KATO setting
  nvmet: avoid queuing keep-alive timer if it is disabled

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: cleanup nvme_configure_apst

Remove a level of indentation from the main code implementating the table
search by using a goto for the APST not supported case.  Also move the
main comment above the function.

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

nvme: do not try to reconfigure APST when the controller is not live

Do not call nvme_configure_apst when the controller is not live, given
that nvme_configure_apst will fail due the lack of an admin queue when
the controller is being torn down and nvme_set_latency_tolerance is
called from dev_pm_qos_hide_latency_tolerance.

Fixes: 510a405d945b("nvme: fix memory leak for power latency tolerance")
Reported-by: Peng Liu <liupeng17@lenovo.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>

nvme: add 'kato' sysfs attribute

Add a 'kato' controller sysfs attribute to display the current
keep-alive timeout value (if any). This allows userspace to identify
persistent discovery controllers, as these will have a non-zero
KATO value.

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

nvme: sanitize KATO setting

According to the NVMe base spec the KATO commands should be sent
at half of the KATO interval, to properly account for round-trip
times.
As we now will only ever send one KATO command per connection we
can easily use the recommended values.
This also fixes a potential issue where the request timeout for
the KATO command does not match the value in the connect command,
which might be causing spurious connection drops from the target.

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

nvmet: avoid queuing keep-alive timer if it is disabled

Issue following command:
nvme set-feature -f 0xf -v 0 /dev/nvme1n1 # disable keep-alive timer
nvme admin-passthru -o 0x18 /dev/nvme1n1  # send keep-alive command
will make keep-alive timer fired and thus delete the controller like
below:

[247459.907635] nvmet: ctrl 1 keep-alive timer (0 seconds) expired!
[247459.930294] nvmet: ctrl 1 fatal error occurred!

Avoid this by not queuing delayed keep-alive if it is disabled when
keep-alive command is received from the admin queue.

Signed-off-by: Hou Pu <houpu.main@gmail.com>
Tested-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

brd: expose number of allocated pages in debugfs

While the maximum size of each ramdisk is defined either as a module
parameter, or compile time default, it's impossible to know how many pages
have currently been allocated by each ram%d device, since they're
allocated when used and never freed.

This patch creates a new directory at this location:

/sys/kernel/debug/ramdisk_pages/

which will contain a file named "ram%d" for each instantiated ramdisk on
the system. The file is read-only, and read() will output the number of
pages currently held by that ramdisk.

We lose track how much memory a ramdisk is using as pages once used are
simply recycled but never freed.

In instances where we exhaust the size of the ramdisk with a file that
exceeds it, encounter ENOSPC and delete the file for mitigation; df would
show decrease in used and increase in available blocks but the since we
have touched all pages, the memory footprint of the ramdisk does not
reflect the blocks used/available count

...
[root@localhost ~]# mkfs.ext2 /dev/ram15
mke2fs 1.45.6 (20-Mar-2020)
Creating filesystem with 4096 1k blocks and 1024 inodes
[root@localhost ~]# mount /dev/ram15 /mnt/ram15/

[root@localhost ~]# cat
/sys/kernel/debug/ramdisk_pages/ram15
58
[root@kerneltest008.06.prn3 ~]# df /dev/ram15
Filesystem     1K-blocks  Used Available Use% Mounted on
/dev/ram15          3963    31      3728   1% /mnt/ram15
[root@kerneltest008.06.prn3 ~]# dd if=/dev/urandom of=/mnt/ram15/test2
bs=1M count=5
dd: error writing '/mnt/ram15/test2': No space left on device
4+0 records in
3+0 records out
4005888 bytes (4.0 MB, 3.8 MiB) copied, 0.0446614 s, 89.7 MB/s
[root@kerneltest008.06.prn3 ~]# df /mnt/ram15/
Filesystem     1K-blocks  Used Available Use% Mounted on
/dev/ram15          3963  3960         0 100% /mnt/ram15
[root@kerneltest008.06.prn3 ~]# cat
/sys/kernel/debug/ramdisk_pages/ram15
1024
[root@kerneltest008.06.prn3 ~]# rm /mnt/ram15/test2
rm: remove regular file '/mnt/ram15/test2'? y
[root@kerneltest008.06.prn3 /var]# df /dev/ram15
Filesystem     1K-blocks  Used Available Use% Mounted on
/dev/ram15          3963    31      3728   1% /mnt/ram15

# Acutal memory footprint
[root@kerneltest008.06.prn3 /var]# cat
/sys/kernel/debug/ramdisk_pages/ram15
1024
...

This debugfs counter will always reveal the accurate number of
permanently allocated pages to the ramdisk.

Signed-off-by: Calvin Owens <calvinowens@fb.com>
[cleaned up the !CONFIG_DEBUG_FS case and API changes for HEAD]
Signed-off-by: Kyle McMartin <jkkm@fb.com>
[rebased]
Signed-off-by: Saravanan D <saravanand@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

ataflop: fix off by one in ataflop_probe()

Smatch complains that the "type > NUM_DISK_MINORS" should be >=
instead of >.  We also need to subtract one from "type" at the start.

Fixes: bf9c0538e485 ("ataflop: use a separate gendisk for each media format")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

ataflop: potential out of bounds in do_format()

The function uses "type" as an array index:

q = unit[drive].disk[type]->queue;

Unfortunately the bounds check on "type" isn't done until later in the
function.  Fix this by moving the bounds check to the start.

Fixes: bf9c0538e485 ("ataflop: use a separate gendisk for each media format")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drbd: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix a couple
of warnings by explicitly adding a break statement instead of just
letting the code fall through to the next, and by adding a fallthrough
pseudo-keyword in places whre the code is intended to fall through.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd: Use strscpy instead of strlcpy

During checkpatch analyzing the following warning message was found:
  WARNING:STRLCPY: Prefer strscpy over strlcpy - see:
  https://lore.kernel.org/r/CAHk-=wgfRnXz0W3D37d01q3JFkr_i_uTL=V6A6G1oUZcprmknw@mail.gmail.com/
Fix it by using strscpy calls instead of strlcpy.

Signed-off-by: Dima Stepanov <dmitrii.stepanov@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210419073722.15351-20-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-clt-sysfs: Remove copy buffer overlap in rnbd_clt_get_path_name

cppcheck report the following error:
  rnbd/rnbd-clt-sysfs.c:522:36: error: The variable 'buf' is used both
  as a parameter and as destination in snprintf(). The origin and
  destination buffers overlap. Quote from glibc (C-library)
  documentation
  (http://www.gnu.org/software/libc/manual/html_mono/libc.html#Formatted-Output-Functions):
  "If copying takes place between objects that overlap as a result of a
  call to sprintf() or snprintf(), the results are undefined."
  [sprintfOverlappingData]
Fix it by initializing the buf variable in the first snprintf call.

Fixes: 91f4acb2801c ("block/rnbd-clt: support mapping two devices")
Signed-off-by: Dima Stepanov <dmitrii.stepanov@ionos.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210419073722.15351-19-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-clt: Remove max_segment_size

We always map with SZ_4K, so do not need max_segment_size.

Cc: Leon Romanovsky <leonro@nvidia.com>
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Acked-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20210419073722.15351-18-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-clt: Generate kobject_uevent when the rnbd device state changes

When an RTRS session state changes, the transport layer generates an event
to RNBD. Then RNBD will change the state of the RNBD client device
accordingly.

This commit add kobject_uevent when the RNBD device state changes. With
this udev rules can be configured to react accordingly.

Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-17-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-srv: Remove unused arguments of rnbd_srv_rdma_ev

struct rtrs_srv is not used when handling rnbd_srv_rdma_ev messages, so
cleaned up
rdma_ev function pointer in rtrs_srv_ops also is changed.

Cc: Leon Romanovsky <leonro@nvidia.com>
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Aleksei Marov <aleksei.marov@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20210419073722.15351-16-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Documentation/ABI/rnbd-clt: Add description for nr_poll_queues

describe how to set nr_poll_queues and enable the polling

Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-15-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-clt: Support polling mode for IO latency optimization

RNBD can make double-queues for irq-mode and poll-mode.
For example, on 4-CPU system 8 request-queues are created,
4 for irq-mode and 4 for poll-mode.
If the IO has HIPRI flag, the block-layer will call .poll function
of RNBD. Then IO is sent to the poll-mode queue.
Add optional nr_poll_queues argument for map_devices interface.

To support polling of RNBD, RTRS client creates connections
for both of irq-mode and direct-poll-mode.

For example, on 4-CPU system it could've create 5 connections:
con[0] => user message (softirq cq)
con[1:4] => softirq cq

After this patch, it can create 9 connections:
con[0] => user message (softirq cq)
con[1:4] => softirq cq
con[5:8] => DIRECT-POLL cq

Cc: Leon Romanovsky <leonro@nvidia.com>
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Acked-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20210419073722.15351-14-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-clt: Fix missing a memory free when unloading the module

When unloading the rnbd-clt module, it does not free a memory
including the filename of the symbolic link to /sys/block/rnbdX.

It is found by kmemleak as below.

unreferenced object 0xffff9f1a83d3c740 (size 16):
  comm "bash", pid 736, jiffies 4295179665 (age 9841.310s)
  hex dump (first 16 bytes):
    21 64 65 76 21 6e 75 6c 6c 62 30 40 62 6c 61 00  !dev!nullb0@bla.
  backtrace:
    [<0000000039f0c55e>] 0xffffffffc0456c24
    [<000000001aab9513>] kernfs_fop_write+0xcf/0x1c0
    [<00000000db5aa4b3>] vfs_write+0xdb/0x1d0
    [<000000007a2e2207>] ksys_write+0x65/0xe0
    [<00000000055e280a>] do_syscall_64+0x50/0x1b0
    [<00000000c2b51831>] entry_SYSCALL_64_after_hwframe+0x49/0xbe

Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-13-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-clt: Improve find_or_create_sess() return check

clang static analysis reports this problem

rnbd-clt.c:1212:11: warning: Branch condition evaluates to a
  garbage value
        else if (!first)
                 ^~~~~~

This is triggered in the find_and_get_or_create_sess() call
because the variable first is not initialized and the
earlier check is specifically for

if (sess == ERR_PTR(-ENOMEM))

This is false positive.

But the if-check can be reduced by initializing first to
false and then returning if the call to find_or_creat_sess()
does not set it to true.  When it remains false, either
sess will be valid or not.  The not case is caught by
find_and_get_or_create_sess()'s caller rnbd_clt_map_device()

sess = find_and_get_or_create_sess(...);
if (IS_ERR(sess))
return ERR_CAST(sess);

Since find_and_get_or_create_sess() initializes first to false
setting it in find_or_create_sess() is not needed.

Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-12-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-srv: Remove force_close file after holding a lock

We changed the rnbd_srv_sess_dev_force_close to use try-lock
because rnbd_srv_sess_dev_force_close and process_msg_close
can generate a deadlock.

Now rnbd_srv_sess_dev_force_close would do nothing
if it fails to get the lock. So removing the force_close
file should be moved to after the lock. Or the force_close
file is removed but the others are not removed.

Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-11-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-srv: Prevent a deadlock generated by accessing sysfs in parallel

We got a warning message below.
When server tries to close one session by force, it locks the sysfs
interface and locks the srv_sess lock.
The problem is that client can send a request to close at the same time.
By close request, server locks the srv_sess lock and locks the sysfs
to remove the sysfs interfaces.

The simplest way to prevent that situation could be just use
mutex_trylock.

[  234.153965] ======================================================
[  234.154093] WARNING: possible circular locking dependency detected
[  234.154219] 5.4.84-storage #5.4.84-1+feature+linux+5.4.y+dbg+20201216.1319+b6b887b~deb10 Tainted: G           O
[  234.154381] ------------------------------------------------------
[  234.154531] kworker/1:1H/618 is trying to acquire lock:
[  234.154651] ffff8887a09db0a8 (kn->count#132){++++}, at: kernfs_remove_by_name_ns+0x40/0x80
[  234.154819]
               but task is already holding lock:
[  234.154965] ffff8887ae5f6518 (&srv_sess->lock){+.+.}, at: rnbd_srv_rdma_ev+0x144/0x1590 [rnbd_server]
[  234.155132]
               which lock already depends on the new lock.

[  234.155311]
               the existing dependency chain (in reverse order) is:
[  234.155462]
               -> #1 (&srv_sess->lock){+.+.}:
[  234.155614]        __mutex_lock+0x134/0xcb0
[  234.155761]        rnbd_srv_sess_dev_force_close+0x36/0x50 [rnbd_server]
[  234.155889]        rnbd_srv_dev_session_force_close_store+0x69/0xc0 [rnbd_server]
[  234.156042]        kernfs_fop_write+0x13f/0x240
[  234.156162]        vfs_write+0xf3/0x280
[  234.156278]        ksys_write+0xba/0x150
[  234.156395]        do_syscall_64+0x62/0x270
[  234.156513]        entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  234.156632]
               -> #0 (kn->count#132){++++}:
[  234.156782]        __lock_acquire+0x129e/0x23a0
[  234.156900]        lock_acquire+0xf3/0x210
[  234.157043]        __kernfs_remove+0x42b/0x4c0
[  234.157161]        kernfs_remove_by_name_ns+0x40/0x80
[  234.157282]        remove_files+0x3f/0xa0
[  234.157399]        sysfs_remove_group+0x4a/0xb0
[  234.157519]        rnbd_srv_destroy_dev_session_sysfs+0x19/0x30 [rnbd_server]
[  234.157648]        rnbd_srv_rdma_ev+0x14c/0x1590 [rnbd_server]
[  234.157775]        process_io_req+0x29a/0x6a0 [rtrs_server]
[  234.157924]        __ib_process_cq+0x8c/0x100 [ib_core]
[  234.158709]        ib_cq_poll_work+0x31/0xb0 [ib_core]
[  234.158834]        process_one_work+0x4e5/0xaa0
[  234.158958]        worker_thread+0x65/0x5c0
[  234.159078]        kthread+0x1e0/0x200
[  234.159194]        ret_from_fork+0x24/0x30
[  234.159309]
               other info that might help us debug this:

[  234.159513]  Possible unsafe locking scenario:

[  234.159658]        CPU0                    CPU1
[  234.159775]        ----                    ----
[  234.159891]   lock(&srv_sess->lock);
[  234.160005]                                lock(kn->count#132);
[  234.160128]                                lock(&srv_sess->lock);
[  234.160250]   lock(kn->count#132);
[  234.160364]
                *** DEADLOCK ***

[  234.160536] 3 locks held by kworker/1:1H/618:
[  234.160677]  #0: ffff8883ca1ed528 ((wq_completion)ib-comp-wq){+.+.}, at: process_one_work+0x40a/0xaa0
[  234.160840]  #1: ffff8883d2d5fe10 ((work_completion)(&cq->work)){+.+.}, at: process_one_work+0x40a/0xaa0
[  234.161003]  #2: ffff8887ae5f6518 (&srv_sess->lock){+.+.}, at: rnbd_srv_rdma_ev+0x144/0x1590 [rnbd_server]
[  234.161168]
               stack backtrace:
[  234.161312] CPU: 1 PID: 618 Comm: kworker/1:1H Tainted: G           O      5.4.84-storage #5.4.84-1+feature+linux+5.4.y+dbg+20201216.1319+b6b887b~deb10
[  234.161490] Hardware name: Supermicro H8QG6/H8QG6, BIOS 3.00       09/04/2012
[  234.161643] Workqueue: ib-comp-wq ib_cq_poll_work [ib_core]
[  234.161765] Call Trace:
[  234.161910]  dump_stack+0x96/0xe0
[  234.162028]  check_noncircular+0x29e/0x2e0
[  234.162148]  ? print_circular_bug+0x100/0x100
[  234.162267]  ? register_lock_class+0x1ad/0x8a0
[  234.162385]  ? __lock_acquire+0x68e/0x23a0
[  234.162505]  ? trace_event_raw_event_lock+0x190/0x190
[  234.162626]  __lock_acquire+0x129e/0x23a0
[  234.162746]  ? register_lock_class+0x8a0/0x8a0
[  234.162866]  lock_acquire+0xf3/0x210
[  234.162982]  ? kernfs_remove_by_name_ns+0x40/0x80
[  234.163127]  __kernfs_remove+0x42b/0x4c0
[  234.163243]  ? kernfs_remove_by_name_ns+0x40/0x80
[  234.163363]  ? kernfs_fop_readdir+0x3b0/0x3b0
[  234.163482]  ? strlen+0x1f/0x40
[  234.163596]  ? strcmp+0x30/0x50
[  234.163712]  kernfs_remove_by_name_ns+0x40/0x80
[  234.163832]  remove_files+0x3f/0xa0
[  234.163948]  sysfs_remove_group+0x4a/0xb0
[  234.164068]  rnbd_srv_destroy_dev_session_sysfs+0x19/0x30 [rnbd_server]
[  234.164196]  rnbd_srv_rdma_ev+0x14c/0x1590 [rnbd_server]
[  234.164345]  ? _raw_spin_unlock_irqrestore+0x43/0x50
[  234.164466]  ? lockdep_hardirqs_on+0x1a8/0x290
[  234.164597]  ? mlx4_ib_poll_cq+0x927/0x1280 [mlx4_ib]
[  234.164732]  ? rnbd_get_sess_dev+0x270/0x270 [rnbd_server]
[  234.164859]  process_io_req+0x29a/0x6a0 [rtrs_server]
[  234.164982]  ? rnbd_get_sess_dev+0x270/0x270 [rnbd_server]
[  234.165130]  __ib_process_cq+0x8c/0x100 [ib_core]
[  234.165279]  ib_cq_poll_work+0x31/0xb0 [ib_core]
[  234.165404]  process_one_work+0x4e5/0xaa0
[  234.165550]  ? pwq_dec_nr_in_flight+0x160/0x160
[  234.165675]  ? do_raw_spin_lock+0x119/0x1d0
[  234.165796]  worker_thread+0x65/0x5c0
[  234.165914]  ? process_one_work+0xaa0/0xaa0
[  234.166031]  kthread+0x1e0/0x200
[  234.166147]  ? kthread_create_worker_on_cpu+0xc0/0xc0
[  234.166268]  ret_from_fork+0x24/0x30
[  234.251591] rnbd_server L243: </dev/loop1@close_device_session>: Device closed
[  234.604221] rnbd_server L264: RTRS Session close_device_session disconnected

Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-10-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-clt: Replace {NO_WAIT,WAIT} with RTRS_PERMIT_{WAIT,NOWAIT}

They are defined with the same value and similar meaning, let's remove
one of them, then we can remove {WAIT,NOWAIT}.

Also change the type of 'wait' from 'int' to 'enum wait_type' to make
it clear.

Cc: Leon Romanovsky <leonro@nvidia.com>
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Guoqing Jiang <guoqing.jiang@ionos.com>
Reviewed-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20210419073722.15351-9-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd: Kill destroy_device_cb

We can use destroy_device directly since destroy_device_cb is just the
wrapper of destroy_device.

Signed-off-by: Guoqing Jiang <guoqing.jiang@ionos.com>
Reviewed-by: Danil Kipnis <danil.kipnis@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210419073722.15351-8-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd: Kill rnbd_clt_destroy_default_group

No need to have it since we can call sysfs_remove_group in the
rnbd_clt_destroy_sysfs_files.

Then rnbd_clt_destroy_sysfs_files is paired with it's counterpart
rnbd_clt_create_sysfs_files.

Signed-off-by: Guoqing Jiang <guoqing.jiang@ionos.com>
Reviewed-by: Danil Kipnis <danil.kipnis@ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210419073722.15351-7-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-clt: Move add_disk(dev->gd) to rnbd_clt_setup_gen_disk

It makes more sense to add gendisk in rnbd_clt_setup_gen_disk, instead
of do it in rnbd_clt_map_device.

Signed-off-by: Guoqing Jiang <guoqing.jiang@gmx.com>
Reviewed-by: Danil Kipnis <danil.kipnis@cloud.ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210419073722.15351-6-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-clt: Remove some arguments from rnbd_client_setup_device

Remove them since both sess and idx can be dereferenced from dev. And
sess is not used in the function.

Signed-off-by: Guoqing Jiang <guoqing.jiang@gmx.com>
Reviewed-by: Danil Kipnis <danil.kipnis@cloud.ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210419073722.15351-5-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/rnbd-clt: Remove some arguments from insert_dev_if_not_exists_devpath

Remove 'pathname' and 'sess' since we can dereference it from 'dev'.

Signed-off-by: Guoqing Jiang <guoqing.jiang@gmx.com>
Reviewed-by: Danil Kipnis <danil.kipnis@cloud.ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210419073722.15351-4-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Documentation/sysfs-block-rnbd: Add descriptions for remap_device and resize

Two sysfs entries, remap_device and resize, are missing.

Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-3-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

MAINTAINERS: Change maintainer for rnbd module

Danil steps down, Haris will take over.
Also update email address to ionos.com, the old
cloud.ionos.com will still work for some time.

Signed-off-by: Danil Kipnis <danil.kipnis@cloud.ionos.com>
Acked-by: Md Haris Iqbal <haris.iqbal@cloud.ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Link: https://lore.kernel.org/r/20210419073722.15351-2-gi-oh.kim@ionos.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

floppy: remove redundant assignment to variable st

The variable st is being assigned a value that is never read and
it is being updated later with a new value. The initialization is
redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Denis Efremov <efremov@linux.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20210415130020.1959951-1-colin.king@canonical.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

floppy: cleanups: remove FLOPPY_SILENT_DCL_CLEAR undef

FLOPPY_SILENT_DCL_CLEAR is not defined anywhere and comes from pre-git
era. Just drop this undef. There is FD_SILENT_DCL_CLEAR which is really
used.

Signed-off-by: Denis Efremov <efremov@linux.com>
Link: https://lore.kernel.org/r/20210416083449.72700-6-efremov@linux.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

floppy: cleanups: use memcpy() to copy reply_buffer

Use memcpy() in raw_cmd_done() to copy reply_buffer instead
of a for loop.

Signed-off-by: Denis Efremov <efremov@linux.com>
Link: https://lore.kernel.org/r/20210416083449.72700-5-efremov@linux.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

floppy: cleanups: use memset() to zero reply_buffer

Use memset() to zero reply buffer in raw_cmd_copyin() instead
of a for loop.

Signed-off-by: Denis Efremov <efremov@linux.com>
Link: https://lore.kernel.org/r/20210416083449.72700-4-efremov@linux.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

floppy: cleanups: use ST0 as reply_buffer index 0

Use ST0 as 0 index for reply_buffer array. get_fdc_version() is the only
function that uses index 0 directly instead of the ST0 define.

Signed-off-by: Denis Efremov <efremov@linux.com>
Link: https://lore.kernel.org/r/20210416083449.72700-3-efremov@linux.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

floppy: cleanups: remove trailing whitespaces

Cleanup trailing whitespaces as checkpatch.pl suggests.

Signed-off-by: Denis Efremov <efremov@linux.com>
Link: https://lore.kernel.org/r/20210416083449.72700-2-efremov@linux.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Merge branch 'md-next' of https://git./linux/kernel/git/song/md into for-5.13/drivers

Pull MD updates from Song:

"1. mddev_find_or_alloc() clean up, from Christoph.
 2. Fix NULL pointer deref with external bitmap, from Sudhakar."

* 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md/bitmap: wait for external bitmap writes to complete during tear down
  md: do not return existing mddevs from mddev_find_or_alloc
  md: refactor mddev_find_or_alloc
  md: factor out a mddev_alloc_unit helper from mddev_find

Merge tag 'nvme-5.13-2021-04-15' of git://git.infradead.org/nvme into for-5.13/drivers

Pull NVMe updates from Christoph:

"nvme updates for Linux 5.13

 - refactor the ioctl code
 - fix a segmentation fault during io parsing error in nvmet-tcp
   (Elad Grupi)
 - fix NULL derefence in nvme_ctrl_fast_io_fail_tmo_show/store
   (Gopal Tiwari)
 - properly respect the sgl_threshold flag in nvme-pci (Niklas Cassel)
 - misc cleanups (Niklas Cassel, Amit Engel, Minwoo Im, Colin Ian King)"

* tag 'nvme-5.13-2021-04-15' of git://git.infradead.org/nvme:
  nvme: fix NULL derefence in nvme_ctrl_fast_io_fail_tmo_show/store
  nvme: let namespace probing continue for unsupported features
  nvme: factor out nvme_ns_open and nvme_ns_release helpers
  nvme: move nvme_ns_head_ops to multipath.c
  nvme: factor out a nvme_tryget_ns_head helper
  nvme: move the ioctl code to a separate file
  nvme: don't bother to look up a namespace for controller ioctls
  nvme: simplify block device ioctl handling for the !multipath case
  nvme: simplify the compat ioctl handling
  nvme: factor out a nvme_ns_ioctl helper
  nvme: pass a user pointer to nvme_nvm_ioctl
  nvme: cleanup setting the disk name
  nvme: add a nvme_ns_head_multipath helper
  nvme: remove single trailing whitespace
  nvme-multipath: remove single trailing whitespace
  nvme-pci: remove single trailing whitespace
  nvme-pci: don't simple map sgl when sgls are disabled
  nvmet: fix a spelling mistake "nubmer" -> "number"
  nvmet-fc: simplify nvmet_fc_alloc_hostport
  nvmet-tcp: fix a segmentation fault during io parsing error

md/bitmap: wait for external bitmap writes to complete during tear down

NULL pointer dereference was observed in super_written() when it tries
to access the mddev structure.

[The below stack trace is from an older kernel, but the problem described
in this patch applies to the mainline kernel.]

[ 1194.474861] task: ffff8fdd20858000 task.stack: ffffb99d40790000
[ 1194.488000] RIP: 0010:super_written+0x29/0xe1
[ 1194.499688] RSP: 0018:ffff8ffb7fcc3c78 EFLAGS: 00010046
[ 1194.512477] RAX: 0000000000000000 RBX: ffff8ffb7bf4a000 RCX: ffff8ffb78991048
[ 1194.527325] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8ffb56b8a200
[ 1194.542576] RBP: ffff8ffb7fcc3c90 R08: 000000000000000b R09: 0000000000000000
[ 1194.558001] R10: ffff8ffb56b8a298 R11: 0000000000000000 R12: ffff8ffb56b8a200
[ 1194.573070] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 1194.588117] FS:  0000000000000000(0000) GS:ffff8ffb7fcc0000(0000) knlGS:0000000000000000
[ 1194.604264] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1194.617375] CR2: 00000000000002b8 CR3: 00000021e040a002 CR4: 00000000007606e0
[ 1194.632327] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1194.647865] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 1194.663316] PKRU: 55555554
[ 1194.674090] Call Trace:
[ 1194.683735]  <IRQ>
[ 1194.692948]  bio_endio+0xae/0x135
[ 1194.703580]  blk_update_request+0xad/0x2fa
[ 1194.714990]  blk_update_bidi_request+0x20/0x72
[ 1194.726578]  __blk_end_bidi_request+0x2c/0x4d
[ 1194.738373]  __blk_end_request_all+0x31/0x49
[ 1194.749344]  blk_flush_complete_seq+0x377/0x383
[ 1194.761550]  flush_end_io+0x1dd/0x2a7
[ 1194.772910]  blk_finish_request+0x9f/0x13c
[ 1194.784544]  scsi_end_request+0x180/0x25c
[ 1194.796149]  scsi_io_completion+0xc8/0x610
[ 1194.807503]  scsi_finish_command+0xdc/0x125
[ 1194.818897]  scsi_softirq_done+0x81/0xde
[ 1194.830062]  blk_done_softirq+0xa4/0xcc
[ 1194.841008]  __do_softirq+0xd9/0x29f
[ 1194.851257]  irq_exit+0xe6/0xeb
[ 1194.861290]  do_IRQ+0x59/0xe3
[ 1194.871060]  common_interrupt+0x1c6/0x382
[ 1194.881988]  </IRQ>
[ 1194.890646] RIP: 0010:cpuidle_enter_state+0xdd/0x2a5
[ 1194.902532] RSP: 0018:ffffb99d40793e68 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff43
[ 1194.917317] RAX: ffff8ffb7fce27c0 RBX: ffff8ffb7fced800 RCX: 000000000000001f
[ 1194.932056] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000
[ 1194.946428] RBP: ffffb99d40793ea0 R08: 0000000000000004 R09: 0000000000002ed2
[ 1194.960508] R10: 0000000000002664 R11: 0000000000000018 R12: 0000000000000003
[ 1194.974454] R13: 000000000000000b R14: ffffffff925715a0 R15: 0000011610120d5a
[ 1194.988607]  ? cpuidle_enter_state+0xcc/0x2a5
[ 1194.999077]  cpuidle_enter+0x17/0x19
[ 1195.008395]  call_cpuidle+0x23/0x3a
[ 1195.017718]  do_idle+0x172/0x1d5
[ 1195.026358]  cpu_startup_entry+0x73/0x75
[ 1195.035769]  start_secondary+0x1b9/0x20b
[ 1195.044894]  secondary_startup_64+0xa5/0xa5
[ 1195.084921] RIP: super_written+0x29/0xe1 RSP: ffff8ffb7fcc3c78
[ 1195.096354] CR2: 00000000000002b8

bio in the above stack is a bitmap write whose completion is invoked after
the tear down sequence sets the mddev structure to NULL in rdev.

During tear down, there is an attempt to flush the bitmap writes, but for
external bitmaps, there is no explicit wait for all the bitmap writes to
complete. For instance, md_bitmap_flush() is called to flush the bitmap
writes, but the last call to md_bitmap_daemon_work() in md_bitmap_flush()
could generate new bitmap writes for which there is no explicit wait to
complete those writes. The call to md_bitmap_update_sb() will return
simply for external bitmaps and the follow-up call to md_update_sb() is
conditional and may not get called for external bitmaps. This results in a
kernel panic when the completion routine, super_written() is called which
tries to reference mddev in the rdev that has been set to
NULL(in unbind_rdev_from_array() by tear down sequence).

The solution is to call md_super_wait() for external bitmaps after the
last call to md_bitmap_daemon_work() in md_bitmap_flush() to ensure there
are no pending bitmap writes before proceeding with the tear down.

Cc: stable@vger.kernel.org
Signed-off-by: Sudhakar Panneerselvam <sudhakar.panneerselvam@oracle.com>
Reviewed-by: Zhao Heming <heming.zhao@suse.com>
Signed-off-by: Song Liu <song@kernel.org>

md: do not return existing mddevs from mddev_find_or_alloc

Instead of returning an existing mddev, just for it to be discarded
later directly return -EEXIST.  Rename the function to mddev_alloc now
that it doesn't find an existing mddev.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>

md: refactor mddev_find_or_alloc

Allocate the new mddev first speculatively, which greatly simplifies
the code flow.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>

md: factor out a mddev_alloc_unit helper from mddev_find

Split out a self contained helper to find a free minor for the md
"unit" number.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>

nvme: fix NULL derefence in nvme_ctrl_fast_io_fail_tmo_show/store

Adding entry for dev_attr_fast_io_fail_tmo to avoid the kernel crash
while reading and writing the fast_io_fail_tmo.

Fixes: 09fbed636382 (nvme: export fast_io_fail_tmo to sysfs)
Signed-off-by: Gopal Tiwari <gtiwari@redhat.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvme: let namespace probing continue for unsupported features

Instead of failing to scan the namespace entirely when unsupported
features are detected, just mark the gendisk hidden but allow other
access like the upcoming per-namespace character device.

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

nvme: factor out nvme_ns_open and nvme_ns_release helpers

These will be reused for the per-namespace character devices.

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: 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: factor out a nvme_tryget_ns_head helper

Add a helper to avoid opencoding ns_head->ref manipulations.

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: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>

nvme: move the ioctl code to a separate file

Split out the ioctl code from core.c into a new file.  Also update
copyrights while we're at it.

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: don't bother to look up a namespace for controller ioctls

Don't bother to look up a namespace just to drop if after retreiving the
controller for the multipath case.  Just look up a live controller for
the subsystem directly.

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

nvme: simplify block device ioctl handling for the !multipath case

Only use the existing ioctl handler for the multipath case, and add a
simpler one that reverts to the pre-multipath case for not shared
use case.

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

nvme: simplify the compat ioctl handling

Don't bother defining a separate compat_ioctl handler, and just handle
the NVME_IOCTL_SUBMIT_IO32 case inline.  Also only defined it for those
ABIs (currently just i386 vs x86_64) that are affected.

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

nvme: factor out a nvme_ns_ioctl helper

Factor out a helper for the namespace based ioctls.

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: pass a user pointer to nvme_nvm_ioctl

Pass the proper user pointer instead of the not all that useful integer
representation.

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

Move the multipath gendisk out of #ifdef CONFIG_NVME_MULTIPATH and add
a new nvme_ns_head_multipath that uses it to check if a ns_head has
a multipath device associated with it.

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
[hch: added the IS_ENABLED, converted a few existing users]
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: remove single trailing whitespace

There is a single trailing whitespace in core.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-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-pci: remove single trailing whitespace

There is a single trailing whitespace in pci.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-pci: don't simple map sgl when sgls are disabled

According to the module parameter description for sgl_threshold,
a value of 0 means that SGLs are disabled.

If SGLs are disabled, we should respect that, even for the case
where the request is made up of a single physical segment.

Fixes: 297910571f08 ("nvme-pci: optimize mapping single segment requests using SGLs")
Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: fix a spelling mistake "nubmer" -> "number"

There is a spelling mistake in a pr_err error message. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet-fc: simplify nvmet_fc_alloc_hostport

Once a host is already created, avoid allocate additional hostports that
will be thrown away. add an helper function to handle host search.

Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Amit Engel <amit.engel@dell.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet-tcp: fix a segmentation fault during io parsing error

In case there is an io that contains inline data and it goes to
parsing error flow, command response will free command and iov
before clearing the data on the socket buffer.
This will delay the command response until receive flow is completed.

Fixes: 872d26a391da ("nvmet-tcp: add NVMe over TCP target driver")
Signed-off-by: Elad Grupi <elad.grupi@dell.com>
Signed-off-by: Hou Pu <houpu.main@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

lightnvm: deprecated OCSSD support and schedule it for removal in Linux 5.15

Lightnvm was an innovative idea to expose more low-level control over SSDs.
But it failed to get properly standardized and remains a non-standarized
extension to NVMe that requires vendor specific quirks for a few now mostly
obsolete SSD devices.  The standardized ZNS command set for NVMe has take
over a lot of the approaches and allows for fully standardized operation.

Remove the Linux code to support open channel SSDs as the few production
deployments of the above mentioned SSDs are using userspace driver stacks
instead of the fairly limited Linux support.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Javier González <javier@javigon.com>
Signed-off-by: Matias Bjørling <mb@lightnvm.io>
Link: https://lore.kernel.org/r/20210413105257.159260-5-matias.bjorling@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

lightnvm: remove duplicate include in lightnvm.h

'linux/blkdev.h' and 'uapi/linux/lightnvm.h' included in 'lightnvm.h'
is duplicated.It is also included in the 5th and 7th line.

Signed-off-by: Zhang Yunkai <zhang.yunkai@zte.com.cn>
Signed-off-by: Matias Bjørling <matias.bjorling@wdc.com>
Link: https://lore.kernel.org/r/20210413105257.159260-4-matias.bjorling@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

lightnvm: return the correct return value

When memdup_user returns an error, memdup_user has two different return
values, use PTR_ERR to get the correct return value.

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Matias Bjørling <matias.bjorling@wdc.com>
Link: https://lore.kernel.org/r/20210413105257.159260-3-matias.bjorling@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

lightnvm: use kobj_to_dev()

This fixs coccicheck warning:

drivers/nvme//host/lightnvm.c:1243:60-61: WARNING opportunity for
kobj_to_dev()

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Matias Bjørling <matias.bjorling@wdc.com>
Link: https://lore.kernel.org/r/20210413105257.159260-2-matias.bjorling@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove the -ERESTARTSYS handling in blkdev_get_by_dev

Now that md has been cleaned up we can get rid of this hack.

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

null_blk: add option for managing virtual boundary

This will enable changing the virtual boundary of null blk devices. For
now, null blk devices didn't have any restriction on the scatter/gather
elements received from the block layer. Add a module parameter and a
configfs option that will control the virtual boundary. This will
enable testing the efficiency of the block layer bounce buffer in case
a suitable application will send discontiguous IO to the given device.

Initial testing with patched FIO showed the following results (64 jobs,
128 iodepth, 1 nullb device):
IO size      READ (virt=false)   READ (virt=true)   Write (virt=false)  Write (virt=true)
----------  ------------------- -----------------  ------------------- -------------------
 1k            10.7M                8482k               10.8M              8471k
 2k            10.4M                8266k               10.4M              8271k
 4k            10.4M                8274k               10.3M              8226k
 8k            10.2M                8131k               9800k              7933k
 16k           9567k                7764k               8081k              6828k
 32k           8865k                7309k               5570k              5153k
 64k           7695k                6586k               2682k              2617k
 128k          5346k                5489k               1320k              1296k

Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Link: https://lore.kernel.org/r/20210412095523.278632-1-mgurtovoy@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

gdrom: fix compilation error

Use the right name for the struct request variable that removes the
following compilation error :-

make --silent --keep-going --jobs=8
O=/home/tuxbuild/.cache/tuxmake/builds/1/tmp ARCH=sh
CROSS_COMPILE=sh4-linux-gnu- 'CC=sccache sh4-linux-gnu-gcc'
'HOSTCC=sccache gcc'

In file included from /builds/linux/include/linux/scatterlist.h:9,
                 from /builds/linux/include/linux/dma-mapping.h:10,
                 from /builds/linux/drivers/cdrom/gdrom.c:16:
/builds/linux/drivers/cdrom/gdrom.c: In function 'gdrom_readdisk_dma':
/builds/linux/drivers/cdrom/gdrom.c:586:61: error: 'rq' undeclared
(first use in this function)
  586 |  __raw_writel(page_to_phys(bio_page(req->bio)) + bio_offset(rq->bio),
      |                                                             ^~

Fixes: 1d2c82001a5f ("gdrom: support highmem")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bcache: fix a regression of code compiling failure in debug.c

The patch "bcache: remove PTR_CACHE" introduces a compiling failure in
debug.c with following error message,
  In file included from drivers/md/bcache/bcache.h:182:0,
                   from drivers/md/bcache/debug.c:9:
  drivers/md/bcache/debug.c: In function 'bch_btree_verify':
  drivers/md/bcache/debug.c:53:19: error: 'c' undeclared (first use in
  this function)
    bio_set_dev(bio, c->cache->bdev);
                     ^
This patch fixes the regression by replacing c->cache->bdev by b->c->
cache->bdev.

Signed-off-by: Coly Li <colyli@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210411134316.80274-8-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bcache: Use 64-bit arithmetic instead of 32-bit

Cast multiple variables to (int64_t) in order to give the compiler
complete information about the proper arithmetic to use. Notice that
these variables are being used in contexts that expect expressions of
type int64_t  (64 bit, signed). And currently, such expressions are
being evaluated using 32-bit arithmetic.

Fixes: d0cf9503e908 ("octeontx2-pf: ethtool fec mode support")
Addresses-Coverity-ID: 1501724 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1501725 ("Unintentional integer overflow")
Addresses-Coverity-ID: 1501726 ("Unintentional integer overflow")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210411134316.80274-7-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

md: bcache: Trivial typo fixes in the file journal.c

s/condidate/candidate/
s/folowing/following/

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210411134316.80274-6-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

md: bcache: avoid -Wempty-body warnings

building with 'make W=1' shows a harmless warning for each user of the
EBUG_ON() macro:

drivers/md/bcache/bset.c: In function 'bch_btree_sort_partial':
drivers/md/bcache/util.h:30:55: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body]
   30 | #define EBUG_ON(cond)                   do { if (cond); } while (0)
      |                                                       ^
drivers/md/bcache/bset.c:1312:9: note: in expansion of macro 'EBUG_ON'
 1312 |         EBUG_ON(oldsize >= 0 && bch_count_data(b) != oldsize);
      |         ^~~~~~~

Reword the macro slightly to avoid the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210411134316.80274-5-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bcache: use NULL instead of using plain integer as pointer

This fixes the following sparse warnings:
drivers/md/bcache/features.c:22:16: warning: Using plain integer as NULL
pointer

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210411134316.80274-4-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bcache: remove PTR_CACHE

Remove the PTR_CACHE inline and replace it with a direct dereference
of c->cache.

(Coly Li: fix the typo from PTR_BUCKET to PTR_CACHE in commit log)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210411134316.80274-3-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

bcache: reduce redundant code in bch_cached_dev_run()

In bch_cached_dev_run(), free(env[1])|free(env[2])|free(buf)
show up three times. This patch introduce out tag in
which free(env[1])|free(env[2])|free(buf) are only called
one time. If we need to call free() when errors occur,
we can set error code to ret, and then goto out tag directly.

Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://lore.kernel.org/r/20210411134316.80274-2-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Merge branch 'md-next' of https://git./linux/kernel/git/song/md into for-5.13/drivers

Pull MD updates from Song:

"These patches fix a race condition with md_release() and md_open()."

* 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md: split mddev_find
  md: factor out a mddev_find_locked helper from mddev_find
  md: md_open returns -EBUSY when entering racing area

md: split mddev_find

Split mddev_find into a simple mddev_find that just finds an existing
mddev by the unit number, and a more complicated mddev_find that deals
with find or allocating a mddev.

This turns out to fix this bug reported by Zhao Heming.

----------------------------- snip ------------------------------
commit d3374825ce57 ("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.

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

*** script ***

about trigger 1 time with 10 tests

`1  node1="15sp3-mdcluster1"
2  node2="15sp3-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..100}; 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 ***

`ID: 2831   TASK: ffff8dd7223b5040  CPU: 0   COMMAND: "mdadm"
 #0 [ffffa15d00a13b90] __schedule at ffffffffb8f1935f
 #1 [ffffa15d00a13ba8] exact_lock at ffffffffb8a4a66d
 #2 [ffffa15d00a13bb0] kobj_lookup at ffffffffb8c62fe3
 #3 [ffffa15d00a13c28] __blkdev_get at ffffffffb89273b9
 #4 [ffffa15d00a13c98] blkdev_get at ffffffffb8927964
 #5 [ffffa15d00a13cb0] do_dentry_open at ffffffffb88dc4b4
 #6 [ffffa15d00a13ce0] path_openat at ffffffffb88f0ccc
 #7 [ffffa15d00a13db8] do_filp_open at ffffffffb88f32bb
 #8 [ffffa15d00a13ee0] do_sys_open at ffffffffb88ddc7d
 #9 [ffffa15d00a13f38] do_syscall_64 at ffffffffb86053cb ffffffffb900008c

or:
[  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.
------------------------------ snip ------------------------------

Cc: stable@vger.kernel.org
Fixes: d3374825ce57 ("md: make devices disappear when they are no longer needed.")
Reported-by: Heming Zhao <heming.zhao@suse.com>
Reviewed-by: Heming Zhao <heming.zhao@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>

md: factor out a mddev_find_locked helper from mddev_find

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

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

md: md_open returns -EBUSY when entering racing area

commit d3374825ce57 ("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: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zhao Heming <heming.zhao@suse.com>
Signed-off-by: Song Liu <song@kernel.org>

drbd: use DEFINE_SPINLOCK() for spinlock

spinlock can be initialized automatically with DEFINE_SPINLOCK()
rather than explicitly calling spin_lock_init().

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Guobin Huang <huangguobin4@huawei.com>
Link: https://lore.kernel.org/r/1617710988-49205-1-git-send-email-huangguobin4@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

swim3: support highmem

swim3 only uses the virtual address of a bio to stash it into the data
transfer using virt_to_bus.  But the ppc32 virt_to_bus just uses the
physical address with an offset.  Replace virt_to_bus with a local hack
that performs the equivalent transformation and stop asking for block
layer bounce buffering.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210406061839.811588-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

floppy: always use the track buffer

Always use the track buffer that is already used for addresses outside
the 16MB address capability of the floppy controller.  This allows to
remove a lot of code that relies on kernel virtual addresses.  With
this gone there is just a single place left that looks at the bio,
which can be converted to memcpy_{from,to}_page, thus removing the need
for the extra block-layer bounce buffering for highmem pages.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210406061755.811522-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

swim: don't call blk_queue_bounce_limit

m68k doesn't support highmem, so don't bother enabling the block layer
bounce buffer code.  Just for safety throw in a depend on !HIGHMEM.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210406061725.811389-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

gdrom: support highmem

The gdrom driver only has a single reference to the virtual address of
the bio data, and uses that only to get the physical address.  Switch
to deriving the physical address from the page directly and thus avoid
bounce buffering highmem data.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210406061648.811275-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: drbd: drbd_nl: Demote half-complete kernel-doc headers

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: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-12-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: xen-blkfront: Demote kernel-doc abuses

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: Lee Jones <lee.jones@linaro.org>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>
Link: https://lore.kernel.org/r/20210312105530.2219008-11-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: drbd: drbd_receiver: Demote less than half complete kernel-doc header

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: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-10-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: drbd: drbd_main: Fix a bunch of function documentation discrepancies

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: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-9-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: drbd: drbd_nl: Make conversion to 'enum drbd_ret_code' explicit

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: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-8-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: drbd: drbd_main: Remove duplicate field initialisation

[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: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-7-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: drbd: drbd_receiver: Demote non-conformant kernel-doc headers

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: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-6-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: drbd: drbd_state: Fix some function documentation issues

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: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-5-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: mtip32xx: mtip32xx: Mark debugging variable 'start' as __maybe_unused

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: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-4-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: drbd: drbd_interval: Demote some kernel-doc abuses and fix another header

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: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20210312105530.2219008-3-lee.jones@linaro.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>