linux-stable.git/block, branch linux-6.15.y

block: Introduce bio_needs_zone_write_plugging()

2025-08-20T16:36:28+00:00

commit f70291411ba20d50008db90a6f0731efac27872c upstream.

In preparation for fixing device mapper zone write handling, introduce
the inline helper function bio_needs_zone_write_plugging() to test if a
BIO requires handling through zone write plugging using the function
blk_zone_plug_bio(). This function returns true for any write
(op_is_write(bio) == true) operation directed at a zoned block device
using zone write plugging, that is, a block device with a disk that has
a zone write plug hash table.

This helper allows simplifying the check on entry to blk_zone_plug_bio()
and used in to protect calls to it for blk-mq devices and DM devices.

Fixes: f211268ed1f9 ("dm: Use the block layer zone append emulation")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20250625093327.548866-3-dlemoal@kernel.org
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: avoid possible overflow for chunk_sectors check in blk_stack_limits()

2025-08-20T16:36:26+00:00

[ Upstream commit 448dfecc7ff807822ecd47a5c052acedca7d09e8 ]

In blk_stack_limits(), we check that the t->chunk_sectors value is a
multiple of the t->physical_block_size value.

However, by finding the chunk_sectors value in bytes, we may overflow
the unsigned int which holds chunk_sectors, so change the check to be
based on sectors.

Reviewed-by: Hannes Reinecke 
Reviewed-by: Martin K. Petersen 
Signed-off-by: John Garry 
Reviewed-by: Damien Le Moal 
Link: https://lore.kernel.org/r/20250729091448.1691334-2-john.g.garry@oracle.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

lib/sbitmap: convert shallow_depth from one word to the whole sbitmap

2025-08-20T16:36:25+00:00

[ Upstream commit 42e6c6ce03fd3e41e39a0f93f9b1a1d9fa664338 ]

Currently elevators will record internal 'async_depth' to throttle
asynchronous requests, and they both calculate shallow_dpeth based on
sb->shift, with the respect that sb->shift is the available tags in one
word.

However, sb->shift is not the availbale tags in the last word, see
__map_depth:

if (index == sb->map_nr - 1)
  return sb->depth - (index << sb->shift);

For consequence, if the last word is used, more tags can be get than
expected, for example, assume nr_requests=256 and there are four words,
in the worst case if user set nr_requests=32, then the first word is
the last word, and still use bits per word, which is 64, to calculate
async_depth is wrong.

One the ohter hand, due to cgroup qos, bfq can allow only one request
to be allocated, and set shallow_dpeth=1 will still allow the number
of words request to be allocated.

Fix this problems by using shallow_depth to the whole sbitmap instead
of per word, also change kyber, mq-deadline and bfq to follow this,
a new helper __map_depth_with_shallow() is introduced to calculate
available bits in each word.

Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20250807032413.1469456-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: ensure discard_granularity is zero when discard is not supported

2025-08-15T10:16:59+00:00

[ Upstream commit fad6551fcf537375702b9af012508156a16a1ff7 ]

Documentation/ABI/stable/sysfs-block states:

  What: /sys/block//queue/discard_granularity
  [...]
  A discard_granularity of 0 means that the device does not support
  discard functionality.

but this got broken when sorting out the block limits updates.  Fix this
by setting the discard_granularity limit to zero when the combined
max_discard_sectors is zero.

Fixes: 3c407dc723bb ("block: default the discard granularity to sector size")
Signed-off-by: Christoph Hellwig 
Reviewed-by: Martin K. Petersen 
Link: https://lore.kernel.org/r/20250731152228.873923-1-hch@lst.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: sanitize chunk_sectors for atomic write limits

2025-08-15T10:16:14+00:00

[ Upstream commit 1de67e8e28fc47d71ee06ffa0185da549b378ffb ]

Currently we just ensure that a non-zero value in chunk_sectors aligns
with any atomic write boundary, as the blk boundary functionality uses
both these values.

However it is also improper to have atomic write unit max > chunk_sectors
(for non-zero chunk_sectors), as this would lead to splitting of atomic
write bios (which is disallowed).

Sanitize atomic write unit max against chunk_sectors to avoid any
potential problems.

Fixes: d00eea91deaf3 ("block: Add extra checks in blk_validate_atomic_write_limits()")
Reviewed-by: Nilay Shroff 
Signed-off-by: John Garry 
Reviewed-by: Martin K. Petersen 
Link: https://lore.kernel.org/r/20250711105258.3135198-3-john.g.garry@oracle.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: fix kobject leak in blk_unregister_queue

2025-07-24T06:58:34+00:00

[ Upstream commit 3051247e4faa32a3d90c762a243c2c62dde310db ]

The kobject for the queue, `disk->queue_kobj`, is initialized with a
reference count of 1 via `kobject_init()` in `blk_register_queue()`.
While `kobject_del()` is called during the unregister path to remove
the kobject from sysfs, the initial reference is never released.

Add a call to `kobject_put()` in `blk_unregister_queue()` to properly
decrement the reference count and fix the leak.

Fixes: 2bd85221a625 ("block: untangle request_queue refcounting from sysfs")
Cc: Christoph Hellwig 
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20250711083009.2574432-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: Clear BIO_EMULATES_ZONE_APPEND flag on BIO completion

2025-06-27T10:13:02+00:00

commit f705d33c2f0353039d03e5d6f18f70467d86080e upstream.

When blk_zone_write_plug_bio_endio() is called for a regular write BIO
used to emulate a zone append operation, that is, a BIO flagged with
BIO_EMULATES_ZONE_APPEND, the BIO operation code is restored to the
original REQ_OP_ZONE_APPEND but the BIO_EMULATES_ZONE_APPEND flag is not
cleared. Clear it to fully return the BIO to its orginal definition.

Fixes: 9b1ce7f0c6f8 ("block: Implement zone append emulation")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal 
Reviewed-by: Johannes Thumshirn 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20250611005915.89843-1-dlemoal@kernel.org
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: use plug request list tail for one-shot backmerge attempt

2025-06-27T10:13:02+00:00

commit 961296e89dc3800e6a3abc3f5d5bb4192cf31e98 upstream.

Previously, the block layer stored the requests in the plug list in
LIFO order. For this reason, blk_attempt_plug_merge() would check
just the head entry for a back merge attempt, and abort after that
unless requests for multiple queues existed in the plug list. If more
than one request is present in the plug list, this makes the one-shot
back merging less useful than before, as it'll always fail to find a
quick merge candidate.

Use the tail entry for the one-shot merge attempt, which is the last
added request in the list. If that fails, abort immediately unless
there are multiple queues available. If multiple queues are available,
then scan the list. Ideally the latter scan would be a backwards scan
of the list, but as it currently stands, the plug list is singly linked
and hence this isn't easily feasible.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/linux-block/20250611121626.7252-1-abuehaze@amazon.com/
Reported-by: Hazem Mohamed Abuelfotoh 
Fixes: e70c301faece ("block: don't reorder requests in blk_add_rq_to_plug")
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

block: don't use submit_bio_noacct_nocheck in blk_zone_wplug_bio_work

2025-06-19T13:41:01+00:00

[ Upstream commit cf625013d8741c01407bbb4a60c111b61b9fa69d ]

Bios queued up in the zone write plug have already gone through all all
preparation in the submit_bio path, including the freeze protection.

Submitting them through submit_bio_noacct_nocheck duplicates the work
and can can cause deadlocks when freezing a queue with pending bio
write plugs.

Go straight to ->submit_bio or blk_mq_submit_bio to bypass the
superfluous extra freeze protection and checks.

Fixes: 9b1ce7f0c6f8 ("block: Implement zone append emulation")
Reported-by: Bart Van Assche 
Signed-off-by: Christoph Hellwig 
Reviewed-by: Johannes Thumshirn 
Reviewed-by: Damien Le Moal 
Tested-by: Damien Le Moal 
Link: https://lore.kernel.org/r/20250611044416.2351850-1-hch@lst.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

block: use q->elevator with ->elevator_lock held in elv_iosched_show()

2025-06-19T13:41:01+00:00

[ Upstream commit 94209d27d14104ed828ca88cd5403a99162fe51a ]

Use q->elevator with ->elevator_lock held in elv_iosched_show(), since
the local cached elevator reference may become stale after getting
->elevator_lock.

Reviewed-by: Hannes Reinecke 
Reviewed-by: Nilay Shroff 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20250505141805.2751237-5-ming.lei@redhat.com
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin