linux-stable.git/block/blk.h, branch linux-6.13.y

block: lift bio_is_zone_append to bio.h

2024-11-11T16:06:45+00:00

Make bio_is_zone_append globally available, because file systems need
to use to check for a zone append bio in their end_io handlers to deal
with the block layer emulation.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Reviewed-by: Johannes Thumshirn 
Link: https://lore.kernel.org/r/20241104062647.91160-4-hch@lst.de
Signed-off-by: Jens Axboe

block: always verify unfreeze lock on the owner task

2024-11-07T23:27:22+00:00

commit f1be1788a32e ("block: model freeze & enter queue as lock for
supporting lockdep") tries to apply lockdep for verifying freeze &
unfreeze. However, the verification is only done the outmost freeze and
unfreeze. This way is actually not correct because q->mq_freeze_depth
still may drop to zero on other task instead of the freeze owner task.

Fix this issue by always verifying the last unfreeze lock on the owner
task context, and make sure both the outmost freeze & unfreeze are
verified in the current task.

Fixes: f1be1788a32e ("block: model freeze & enter queue as lock for supporting lockdep")
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20241031133723.303835-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe

block: remove blk_freeze_queue()

2024-11-07T23:27:22+00:00

No one use blk_freeze_queue(), so remove it and the obsolete comment.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20241031133723.303835-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe

block: model freeze & enter queue as lock for supporting lockdep

2024-10-26T13:14:53+00:00

Recently we got several deadlock report[1][2][3] caused by
blk_mq_freeze_queue and blk_enter_queue().

Turns out the two are just like acquiring read/write lock, so model them
as read/write lock for supporting lockdep:

1) model q->q_usage_counter as two locks(io and queue lock)

- queue lock covers sync with blk_enter_queue()

- io lock covers sync with bio_enter_queue()

2) make the lockdep class/key as per-queue:

- different subsystem has very different lock use pattern, shared lock
 class causes false positive easily

- freeze_queue degrades to no lock in case that disk state becomes DEAD
  because bio_enter_queue() won't be blocked any more

- freeze_queue degrades to no lock in case that request queue becomes dying
  because blk_enter_queue() won't be blocked any more

3) model blk_mq_freeze_queue() as acquire_exclusive & try_lock
- it is exclusive lock, so dependency with blk_enter_queue() is covered

- it is trylock because blk_mq_freeze_queue() are allowed to run
  concurrently

4) model blk_enter_queue() & bio_enter_queue() as acquire_read()
- nested blk_enter_queue() are allowed

- dependency with blk_mq_freeze_queue() is covered

- blk_queue_exit() is often called from other contexts(such as irq), and
it can't be annotated as lock_release(), so simply do it in
blk_enter_queue(), this way still covered cases as many as possible

With lockdep support, such kind of reports may be reported asap and
needn't wait until the real deadlock is triggered.

For example, lockdep report can be triggered in the report[3] with this
patch applied.

[1] occasional block layer hang when setting 'echo noop > /sys/block/sda/queue/scheduler'
https://bugzilla.kernel.org/show_bug.cgi?id=219166

[2] del_gendisk() vs blk_queue_enter() race condition
https://lore.kernel.org/linux-block/20241003085610.GK11458@google.com/

[3] queue_freeze & queue_enter deadlock in scsi
https://lore.kernel.org/linux-block/ZxG38G9BuFdBpBHZ@fedora/T/#u

Reviewed-by: Christoph Hellwig 
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20241025003722.3630252-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe

block: add support for defining read-only partitions

2024-10-22T14:14:56+00:00

Add support for defining read-only partitions and complete support for
it in the cmdline partition parser as the additional "ro" after a
partition is scanned but never actually applied.

Signed-off-by: Christian Marangi 
Reviewed-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20241002221306.4403-2-ansuelsmth@gmail.com
Signed-off-by: Jens Axboe

block: kill blk_do_io_stat() helper

2024-10-22T14:14:56+00:00

It's now just checking whether or not RQF_IO_STAT is set, so let's get
rid of it and just open-code the specific flag that is being checked.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: move iostat check into blk_acount_io_start()

2024-10-22T14:14:56+00:00

Rather than have blk_do_io_stat() check for both RQF_IO_STAT and whether
the request is a passthrough requests every time, move both of those
checks into blk_account_io_start(). Then blk_do_io_stat() can be reduced
to just checking for RQF_IO_STAT.

Reviewed-by: Keith Busch 
Reviewed-by: Anuj Gupta 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: implement async io_uring discard cmd

2024-09-11T16:45:28+00:00

io_uring allows implementing custom file specific asynchronous
operations via the fops->uring_cmd callback, a.k.a. IORING_OP_URING_CMD
requests or just io_uring commands. Use it to add support for async
discards.

Normally, it first tries to queue up bios in a non-blocking context,
and if that fails, we'd retry from a blocking context by returning
-EAGAIN to the core io_uring. We always get the result from bios
asynchronously by setting a custom bi_end_io callback, at which point
we drag the request into the task context to either reissue or complete
it and post a completion to the user.

Unlike ioctl(BLKDISCARD) with stronger guarantees against races, we only
do a best effort attempt to invalidate page cache, and it can race with
any writes and reads and leave page cache stale. It's the same kind of
races we allow to direct writes.

Also, apart from cases where discarding is not allowed at all, e.g.
discards are not supported or the file/device is read only, the user
should assume that the sector range on disk is not valid anymore, even
when an error was returned to the user.

Suggested-by: Conrad Meyer 
Signed-off-by: Pavel Begunkov 
Link: https://lore.kernel.org/r/2b5210443e4fa0257934f73dfafcc18a77cd0e09.1726072086.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe

block: Added folio-ized version of bio_add_hw_page()

2024-09-11T13:24:00+00:00

Added new bio_add_hw_folio() function as a wrapper around
bio_add_hw_page(). This is a prep patch.

Signed-off-by: Kundan Kumar 
Tested-by: Luis Chamberlain 
Reviewed-by: Matthew Wilcox (Oracle) 
Link: https://lore.kernel.org/r/20240911064935.5630-2-kundan.kumar@samsung.com
Signed-off-by: Jens Axboe

block: don't use bio_split_rw on misc operations

2024-08-29T10:32:32+00:00

bio_split_rw is designed to split read and write bios with a payload.
Currently it is called by __bio_split_to_limits for all operations not
explicitly list, which works because bio_may_need_split explicitly checks
for bi_vcnt == 1 and thus skips the bypass if there is no payload and
bio_for_each_bvec loop will never execute it's body if bi_size is 0.

But all this is hard to understand, fragile and wasted pointless cycles.
Switch __bio_split_to_limits to only call bio_split_rw for READ and
WRITE command and don't attempt any kind split for operation that do not
require splitting.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Tested-by: Hans Holmberg 
Reviewed-by: Hans Holmberg 
Link: https://lore.kernel.org/r/20240826173820.1690925-5-hch@lst.de
Signed-off-by: Jens Axboe