null_blk: Use strscpy() instead of strscpy_pad() in null_add_dev()

blk_mq_alloc_disk() already zero-initializes the destination buffer,
making strscpy() sufficient for safely copying the disk's name

null_blk: Use strscpy() instead of strscpy_pad() in null_add_dev()

blk_mq_alloc_disk() already zero-initializes the destination buffer,
making strscpy() sufficient for safely copying the disk's name. The
additional NUL-padding performed by strscpy_pad() is unnecessary.

If the destination buffer has a fixed length, strscpy() automatically
determines its size using sizeof() when the argument is omitted. This
makes the explicit size argument unnecessary.

The source string is also NUL-terminated and meets the __must_be_cstr()
requirement of strscpy().

No functional changes intended.

Signed-off-by: Thorsten Blum <[email protected]>
Reviewed-by: Zhu Yanjun <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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block: change blk_mq_add_to_batch() third argument type to bool

Commit 1f47ed294a2b ("block: cleanup and fix batch completion adding
conditions") modified the evaluation criteria for the third argum

block: change blk_mq_add_to_batch() third argument type to bool

Commit 1f47ed294a2b ("block: cleanup and fix batch completion adding
conditions") modified the evaluation criteria for the third argument,
'ioerror', in the blk_mq_add_to_batch() function. Initially, the
function had checked if 'ioerror' equals zero. Following the commit, it
started checking for negative error values, with the presumption that
such values, for instance -EIO, would be passed in.

However, blk_mq_add_to_batch() callers do not pass negative error
values. Instead, they pass status codes defined in various ways:

- NVMe PCI and Apple drivers pass NVMe status code
- virtio_blk driver passes the virtblk request header status byte
- null_blk driver passes blk_status_t

These codes are either zero or positive, therefore the revised check
fails to function as intended. Specifically, with the NVMe PCI driver,
this modification led to the failure of the blktests test case nvme/039.
In this test scenario, errors are artificially injected to the NVMe
driver, resulting in positive NVMe status codes passed to
blk_mq_add_to_batch(), which unexpectedly processes the failed I/O in a
batch. Hence the failure.

To correct the ioerror check within blk_mq_add_to_batch(), make all
callers to uniformly pass the argument as boolean. Modify the callers to
check their specific status codes and pass the boolean value 'is_error'.
Also describe the arguments of blK_mq_add_to_batch as kerneldoc.

Fixes: 1f47ed294a2b ("block: cleanup and fix batch completion adding conditions")
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[axboe: fold in documentation update]
Signed-off-by: Jens Axboe <[email protected]>

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badblocks: use sector_t instead of int to avoid truncation of badblocks length

There is a truncation of badblocks length issue when set badblocks as
follow:

echo "2055 4294967299" > bad_blocks
cat

badblocks: use sector_t instead of int to avoid truncation of badblocks length

There is a truncation of badblocks length issue when set badblocks as
follow:

echo "2055 4294967299" > bad_blocks
cat bad_blocks
2055 3

Change 'sectors' argument type from 'int' to 'sector_t'.

This change avoids truncation of badblocks length for large sectors by
replacing 'int' with 'sector_t' (u64), enabling proper handling of larger
disk sizes and ensuring compatibility with 64-bit sector addressing.

Fixes: 9e0e252a048b ("badblocks: Add core badblock management code")
Signed-off-by: Zheng Qixing <[email protected]>
Reviewed-by: Yu Kuai <[email protected]>
Acked-by: Coly Li <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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badblocks: return boolean from badblocks_set() and badblocks_clear()

Change the return type of badblocks_set() and badblocks_clear()
from int to bool, indicating success or failure. Specifically:

-

badblocks: return boolean from badblocks_set() and badblocks_clear()

Change the return type of badblocks_set() and badblocks_clear()
from int to bool, indicating success or failure. Specifically:

- _badblocks_set() and _badblocks_clear() functions now return
true for success and false for failure.
- All calls to these functions are updated to handle the new
boolean return type.
- This change improves code clarity and ensures a more consistent
handling of success and failure states.

Signed-off-by: Zheng Qixing <[email protected]>
Reviewed-by: Yu Kuai <[email protected]>
Acked-by: Coly Li <[email protected]>
Acked-by: Ira Weiny <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: do partial IO for bad blocks

The current null_blk implementation checks if any bad blocks exist in
the target blocks of each IO. If so, the IO fails and data is not
transferred for all of

null_blk: do partial IO for bad blocks

The current null_blk implementation checks if any bad blocks exist in
the target blocks of each IO. If so, the IO fails and data is not
transferred for all of the IO target blocks. However, when real storage
devices have bad blocks, the devices may transfer data partially up to
the first bad blocks (e.g., SAS drives). Especially, when the IO is a
write operation, such partial IO leaves partially written data on the
device.

To simulate such partial IO using null_blk, introduce the new parameter
'badblocks_partial_io'. When this parameter is set,
null_handle_badblocks() returns the number of the sectors for the
partial IO as its third pointer argument. Pass the returned number of
sectors to the following calls to null_handle_memory_backend() in
null_process_cmd() and null_zone_write().

Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: pass transfer size to null_handle_rq()

As preparation to support partial data transfer, add a new argument to
null_handle_rq() to pass the number of sectors to transfer. While at it,
renam

null_blk: pass transfer size to null_handle_rq()

As preparation to support partial data transfer, add a new argument to
null_handle_rq() to pass the number of sectors to transfer. While at it,
rename the function from null_handle_rq to null_handle_data_transfer.
This commit does not change the behavior.

Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: replace null_process_cmd() call in null_zone_write()

As a preparation to support partial data transfer due to badblocks,
replace the null_process_cmd() call in null_zone_write() with equiv

null_blk: replace null_process_cmd() call in null_zone_write()

As a preparation to support partial data transfer due to badblocks,
replace the null_process_cmd() call in null_zone_write() with equivalent
calls to null_handle_badblocks() and null_handle_memory_backed(). This
commit does not change behavior. It will enable null_handle_badblocks()
to return the size of partial data transfer in the following commit,
allowing null_zone_write() to move write pointers appropriately.

Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: introduce badblocks_once parameter

When IO errors happen on real storage devices, the IOs repeated to the
same target range can success by virtue of recovery features by devices,
such as r

null_blk: introduce badblocks_once parameter

When IO errors happen on real storage devices, the IOs repeated to the
same target range can success by virtue of recovery features by devices,
such as reserved block assignment. To simulate such IO errors and
recoveries, introduce the new parameter badblocks_once parameter. When
this parameter is set to 1, the specified badblocks are cleared after
the first IO error, so that the next IO to the blocks succeed.

Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: generate null_blk configfs features string

The null_blk configfs file 'features' provides a string that lists
available null_blk features for userspace programs to reference.
The string is

null_blk: generate null_blk configfs features string

The null_blk configfs file 'features' provides a string that lists
available null_blk features for userspace programs to reference.
The string is defined as a long constant in the code, which tends to be
forgotten for updates. It also causes checkpatch.pl to report
"WARNING: quoted string split across lines".

To avoid these drawbacks, generate the feature string on the fly. Refer
to the ca_name field of each element in the nullb_device_attrs table and
concatenate them in the given buffer. Also, sorted nullb_device_attrs
table elements in alphabetical order.

Of note is that the feature "index" was missing before this commit.
This commit adds it to the generated string.

Suggested-by: Bart Van Assche <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Shin'ichiro Kawasaki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: Switch to use hrtimer_setup()

hrtimer_setup() takes the callback function pointer as argument and
initializes the timer completely.

Replace hrtimer_init() and the open coded initializatio

null_blk: Switch to use hrtimer_setup()

hrtimer_setup() takes the callback function pointer as argument and
initializes the timer completely.

Replace hrtimer_init() and the open coded initialization of
hrtimer::function with the new setup mechanism.

Patch was created by using Coccinelle.

Signed-off-by: Nam Cao <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/all/076cd30acb4b2d6b699f3c80463a8983530d4f06.1738746821.git.namcao@linutronix.de

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block: remove BLK_MQ_F_NO_SCHED

The only queues that really can't support a scheduler are those that
do not have a gendisk associated with them, and thus can't be used for
non-passthrough commands.

block: remove BLK_MQ_F_NO_SCHED

The only queues that really can't support a scheduler are those that
do not have a gendisk associated with them, and thus can't be used for
non-passthrough commands. In addition to those null_blk can optionally
set the flag, which is a bad odd. Replace the null_blk usage with
BLK_MQ_F_NO_SCHED_BY_DEFAULT to keep the expected semantics and then
remove BLK_MQ_F_NO_SCHED as the non-disk queues never call into
elevator_init_mq or blk_register_queue which adds the sysfs attributes.

Signed-off-by: Christoph Hellwig <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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block: remove BLK_MQ_F_SHOULD_MERGE

BLK_MQ_F_SHOULD_MERGE is set for all tag_sets except those that purely
process passthrough commands (bsg-lib, ufs tmf, various nvme admin
queues) and thus don't e

block: remove BLK_MQ_F_SHOULD_MERGE

BLK_MQ_F_SHOULD_MERGE is set for all tag_sets except those that purely
process passthrough commands (bsg-lib, ufs tmf, various nvme admin
queues) and thus don't even check the flag. Remove it to simplify the
driver interface.

Signed-off-by: Christoph Hellwig <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: Remove accesses to page->index

Use page->private to store the index instead of page->index.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Damien Le Moal <dlemo

null_blk: Remove accesses to page->index

Use page->private to store the index instead of page->index.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: Add rotational feature support

To facilitate testing of kernel functions related to the rotational
feature (BLK_FEAT_ROTATIONAL) of a block device (e.g. NVMe rotational
bit support), add t

null_blk: Add rotational feature support

To facilitate testing of kernel functions related to the rotational
feature (BLK_FEAT_ROTATIONAL) of a block device (e.g. NVMe rotational
bit support), add the rotational boolean configfs attribute and module
parameter to the null_blk driver. If set, a null block device will
report being a rotational device through it queue limits features with
the BLK_FEAT_ROTATIONAL flag.

Signed-off-by: Damien Le Moal <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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block: add a rq_list type

Replace the semi-open coded request list helpers with a proper rq_list
type that mirrors the bio_list and has head and tail pointers. Besides
better type safety this actua

block: add a rq_list type

Replace the semi-open coded request list helpers with a proper rq_list
type that mirrors the bio_list and has head and tail pointers. Besides
better type safety this actually allows to insert at the tail of the
list, which will be useful soon.

Signed-off-by: Christoph Hellwig <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: Don't bother validating blocksize

The block queue limits validation does this for us now.

Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: John Garry <[email protected]>
R

null_blk: Don't bother validating blocksize

The block queue limits validation does this for us now.

Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: John Garry <[email protected]>
Reviewed-by: Zhu Yanjun <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Stefan Hajnoczi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: Introduce the zone_full parameter

Allow creating a zoned null_blk device with the initial state of its
sequential write required zones to be FULL. This is convenient to avoid
having to fir

null_blk: Introduce the zone_full parameter

Allow creating a zoned null_blk device with the initial state of its
sequential write required zones to be FULL. This is convenient to avoid
having to first write these zones to perform read performance evaluation
or test zone management operations such as zone reset (and zone reset
all).

Signed-off-by: Damien Le Moal <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Reviewed-by: Martin K. Petersen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: don't initialize static 'g_virt_boundary' to false

No functional changes intended.

Signed-off-by: Zhu Yanjun <[email protected]>
Link: https://lore.kernel.org/r/20240704010638.324349-1

null_blk: don't initialize static 'g_virt_boundary' to false

No functional changes intended.

Signed-off-by: Zhu Yanjun <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: Fix description of the fua parameter

The description of the fua module parameter is defined using
MODULE_PARM_DESC() with the first argument passed being "zoned". That is
the wrong name, o

null_blk: Fix description of the fua parameter

The description of the fua module parameter is defined using
MODULE_PARM_DESC() with the first argument passed being "zoned". That is
the wrong name, obviously. Fix that by using the correct "fua" parameter
name so that "modinfo null_blk" displays correct information.

Fixes: f4f84586c8b9 ("null_blk: Introduce fua attribute")
Cc: [email protected]
Signed-off-by: Damien Le Moal <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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block: move the nonrot flag to queue_limits

Move the nonrot flag into the queue_limits feature field so that it can
be set atomically with the queue frozen.

Use the chance to switch to defaulting t

block: move the nonrot flag to queue_limits

Move the nonrot flag into the queue_limits feature field so that it can
be set atomically with the queue frozen.

Use the chance to switch to defaulting to non-rotational and require
the driver to opt into rotational, which matches the polarity of the
sysfs interface.

For the z2ram, ps3vram, 2x memstick, ubiblock and dcssblk the new
rotational flag is not set as they clearly are not rotational despite
this being a behavior change. There are some other drivers that
unconditionally set the rotational flag to keep the existing behavior
as they arguably can be used on rotational devices even if that is
probably not their main use today (e.g. virtio_blk and drbd).

The flag is automatically inherited in blk_stack_limits matching the
existing behavior in dm and md.

Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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block: move cache control settings out of queue->flags

Move the cache control settings into the queue_limits so that the flags
can be set atomically with the device queue frozen.

Add new features a

block: move cache control settings out of queue->flags

Move the cache control settings into the queue_limits so that the flags
can be set atomically with the device queue frozen.

Add new features and flags field for the driver set flags, and internal
(usually sysfs-controlled) flags in the block layer. Note that we'll
eventually remove enough field from queue_limits to bring it back to the
previous size.

The disable flag is inverted compared to the previous meaning, which
means it now survives a rescan, similar to the max_sectors and
max_discard_sectors user limits.

The FLUSH and FUA flags are now inherited by blk_stack_limits, which
simplified the code in dm a lot, but also causes a slight behavior
change in that dm-switch and dm-unstripe now advertise a write cache
despite setting num_flush_bios to 0. The I/O path will handle this
gracefully, but as far as I can tell the lack of num_flush_bios
and thus flush support is a pre-existing data integrity bug in those
targets that really needs fixing, after which a non-zero num_flush_bios
should be required in dm for targets that map to underlying devices.

Signed-off-by: Christoph Hellwig <[email protected]>
Acked-by: Ulf Hansson <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: fix validation of block size

Block size should be between 512 and PAGE_SIZE and be a power of 2. The current
check does not validate this, so update the check.

Without this patch, null_bl

null_blk: fix validation of block size

Block size should be between 512 and PAGE_SIZE and be a power of 2. The current
check does not validate this, so update the check.

Without this patch, null_blk would Oops due to a null pointer deref when
loaded with bs=1536 [1].

Link: https://lore.kernel.org/all/[email protected]/

Signed-off-by: Andreas Hindborg <[email protected]>
Reviewed-by: Ming Lei <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[axboe: remove unnecessary braces and != 0 check]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: Fix return value of nullb_device_power_store()

When powering on a null_blk device that is not already on, the return
value ret that is initialized to be count is reused to check the return

null_blk: Fix return value of nullb_device_power_store()

When powering on a null_blk device that is not already on, the return
value ret that is initialized to be count is reused to check the return
value of null_add_dev(), leading to nullb_device_power_store() to return
null_add_dev() return value (0 on success) instead of "count".
So make sure to set ret to be equal to count when there are no errors.

Fixes: a2db328b0839 ("null_blk: fix null-ptr-dereference while configuring 'power' and 'submit_queues'")
Signed-off-by: Damien Le Moal <[email protected]>
Reviewed-by: Yu Kuai <[email protected]>
Reviewed-by: Kanchan Joshi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: fix null-ptr-dereference while configuring 'power' and 'submit_queues'

Writing 'power' and 'submit_queues' concurrently will trigger kernel
panic:

Test script:

modprobe null_blk nr_devic

null_blk: fix null-ptr-dereference while configuring 'power' and 'submit_queues'

Writing 'power' and 'submit_queues' concurrently will trigger kernel
panic:

Test script:

modprobe null_blk nr_devices=0
mkdir -p /sys/kernel/config/nullb/nullb0
while true; do echo 1 > submit_queues; echo 4 > submit_queues; done &
while true; do echo 1 > power; echo 0 > power; done

Test result:

BUG: kernel NULL pointer dereference, address: 0000000000000148
Oops: 0000 [#1] PREEMPT SMP
RIP: 0010:__lock_acquire+0x41d/0x28f0
Call Trace:
<TASK>
lock_acquire+0x121/0x450
down_write+0x5f/0x1d0
simple_recursive_removal+0x12f/0x5c0
blk_mq_debugfs_unregister_hctxs+0x7c/0x100
blk_mq_update_nr_hw_queues+0x4a3/0x720
nullb_update_nr_hw_queues+0x71/0xf0 [null_blk]
nullb_device_submit_queues_store+0x79/0xf0 [null_blk]
configfs_write_iter+0x119/0x1e0
vfs_write+0x326/0x730
ksys_write+0x74/0x150

This is because del_gendisk() can concurrent with
blk_mq_update_nr_hw_queues():

nullb_device_power_store nullb_apply_submit_queues
null_del_dev
del_gendisk
nullb_update_nr_hw_queues
if (!dev->nullb)
// still set while gendisk is deleted
return 0
blk_mq_update_nr_hw_queues
dev->nullb = NULL

Fix this problem by resuing the global mutex to protect
nullb_device_power_store() and nullb_update_nr_hw_queues() from configfs.

Fixes: 45919fbfe1c4 ("null_blk: Enable modifying 'submit_queues' after an instance has been configured")
Reported-and-tested-by: Yi Zhang <[email protected]>
Closes: https://lore.kernel.org/all/CAHj4cs9LgsHLnjg8z06LQ3Pr5cax-+Ps+xT7AP7TPnEjStuwZA@mail.gmail.com/
Signed-off-by: Yu Kuai <[email protected]>
Reviewed-by: Zhu Yanjun <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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null_blk: Fix two sparse warnings

Fix the following sparse warnings:

drivers/block/null_blk/main.c:1243:35: warning: incorrect type in return expression (different base types)
drivers/block/null_bl

null_blk: Fix two sparse warnings

Fix the following sparse warnings:

drivers/block/null_blk/main.c:1243:35: warning: incorrect type in return expression (different base types)
drivers/block/null_blk/main.c:1243:35: expected int
drivers/block/null_blk/main.c:1243:35: got restricted blk_status_t
drivers/block/null_blk/main.c:1291:30: warning: incorrect type in return expression (different base types)
drivers/block/null_blk/main.c:1291:30: expected restricted blk_status_t
drivers/block/null_blk/main.c:1291:30: got int

Cc: Christoph Hellwig <[email protected]>
Cc: Damien Le Moal <[email protected]>
Signed-off-by: Bart Van Assche <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

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