Commit Graph

1382501 Commits

Author SHA1 Message Date
Caleb Sander Mateos
692cf47e1a ublk: don't access ublk_queue in ublk_register_io_buf()
For ublk servers with many ublk queues, accessing the ublk_queue in
ublk_register_io_buf() is a frequent cache miss. Get the flags from the
ublk_device instead, which is accessed earlier in
ublk_ch_uring_cmd_local().

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-20 06:36:27 -06:00
Caleb Sander Mateos
8a81926e45 ublk: pass ublk_device to ublk_register_io_buf()
Avoid repeating the 2 dereferences to get the ublk_device from the
io_uring_cmd by passing it from ublk_ch_uring_cmd_local() to
ublk_register_io_buf().

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-20 06:36:27 -06:00
Caleb Sander Mateos
b40dcdf823 ublk: don't dereference ublk_queue in ublk_check_and_get_req()
For ublk servers with many ublk queues, accessing the ublk_queue in
ublk_ch_{read,write}_iter() is a frequent cache miss. Get the flags and
queue depth from the ublk_device instead, which is accessed just before.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-20 06:36:27 -06:00
Caleb Sander Mateos
5125535f90 ublk: don't dereference ublk_queue in ublk_ch_uring_cmd_local()
For ublk servers with many ublk queues, accessing the ublk_queue to
handle a ublk command is a frequent cache miss. Get the queue depth from
the ublk_device instead, which is accessed just before.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-20 06:36:27 -06:00
Caleb Sander Mateos
d74a383ec7 ublk: add helpers to check ublk_device flags
Introduce ublk_device analogues of the ublk_queue flag helpers:
- ublk_support_zero_copy() -> ublk_dev_support_user_copy()
- ublk_support_auto_buf_reg() -> ublk_dev_support_auto_buf_reg()
- ublk_support_user_copy() -> ublk_dev_support_user_copy()
- ublk_need_map_io() -> ublk_dev_need_map_io()
- ublk_need_req_ref() -> ublk_dev_need_req_ref()
- ublk_need_get_data() -> ublk_dev_need_get_data()

These will be used in subsequent changes to avoid accessing the
ublk_queue just for the flags, and instead use the ublk_device.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-20 06:36:27 -06:00
Caleb Sander Mateos
0265595002 ublk: don't pass ublk_queue to __ublk_fail_req()
__ublk_fail_req() only uses the ublk_queue to get the ublk_device, which
its caller already has. So just pass the ublk_device directly.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-20 06:36:27 -06:00
Caleb Sander Mateos
b7e255b034 ublk: don't pass q_id to ublk_queue_cmd_buf_size()
ublk_queue_cmd_buf_size() only needs the queue depth, which is the same
for all queues. Get the queue depth from the ublk_device instead so the
q_id parameter can be dropped.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-20 06:36:27 -06:00
Caleb Sander Mateos
163f80dabf ublk: remove ubq check in ublk_check_and_get_req()
ublk_get_queue() never returns a NULL pointer, so there's no need to
check its return value in ublk_check_and_get_req(). Drop the check.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-20 06:36:27 -06:00
Uday Shankar
a755da0dd0 selftests: ublk: add test to verify that feat_map is complete
Add a test that verifies that the currently running kernel does not
report support for any features that are unrecognized by kublk. This
should catch cases where features are added without updating kublk's
feat_map accordingly, which has happened multiple times in the past (see
[1], [2]).

Note that this new test may fail if the test suite is older than the
kernel, and the newer kernel contains a newly introduced feature. I
believe this is not a use case we currently care about - we only care
about newer test suites passing on older kernels.

[1] https://lore.kernel.org/linux-block/20250606214011.2576398-1-csander@purestorage.com/t/#u
[2] https://lore.kernel.org/linux-block/2a370ab1-d85b-409d-b762-f9f3f6bdf705@nvidia.com/t/#m1c520a058448d594fd877f07804e69b28908533f

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-19 11:06:15 -06:00
Uday Shankar
742bcc1101 selftests: ublk: kublk: add UBLK_F_BUF_REG_OFF_DAEMON to feat_map
When UBLK_F_BUF_REG_OFF_DAEMON was added, we missed updating kublk's
feat_map, which results in the feature being reported as "unknown." Add
UBLK_F_BUF_REG_OFF_DAEMON to feat_map to fix this.

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-19 11:06:15 -06:00
Uday Shankar
1f924cf781 selftests: ublk: kublk: simplify feat_map definition
Simplify the definition of feat_map by introducing a helper macro
FEAT_NAME to avoid having to type the feature name twice. As a side
effect, this changes the names in the feature list to be the full macro
name instead of the abbreviated names that were used before, but this is
a good change for clarity.

Using the full feature macro names ruins the alignment of the output, so
change the output format to put each feature's hex value before its
name, as this is easier to align nicely. The output now looks as
follows:

root# ./kublk features
ublk_drv features: 0x7fff
0x1               : UBLK_F_SUPPORT_ZERO_COPY
0x2               : UBLK_F_URING_CMD_COMP_IN_TASK
0x4               : UBLK_F_NEED_GET_DATA
0x8               : UBLK_F_USER_RECOVERY
0x10              : UBLK_F_USER_RECOVERY_REISSUE
0x20              : UBLK_F_UNPRIVILEGED_DEV
0x40              : UBLK_F_CMD_IOCTL_ENCODE
0x80              : UBLK_F_USER_COPY
0x100             : UBLK_F_ZONED
0x200             : UBLK_F_USER_RECOVERY_FAIL_IO
0x400             : UBLK_F_UPDATE_SIZE
0x800             : UBLK_F_AUTO_BUF_REG
0x1000            : UBLK_F_QUIESCE
0x2000            : UBLK_F_PER_IO_DAEMON
0x4000            : unknown

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-19 11:06:15 -06:00
Yu Kuai
336aec7b06 blk-throttle: fix throtl_data leak during disk release
Tightening the throttle activation check in blk_throtl_activated() to
require both q->td presence and policy bit set introduced a memory leak
during disk release:

blkg_destroy_all() clears the policy bit first during queue deactivation,
causing subsequent blk_throtl_exit() to skip throtl_data cleanup when
blk_throtl_activated() fails policy check.

Idealy we should avoid modifying blk_throtl_exit() activation check because
it's intuitive that blk-throtl start from blk_throtl_init() and end in
blk_throtl_exit(). However, call blk_throtl_exit() before
blkg_destroy_all() will make a long term deadlock problem easier to
trigger[1], hence fix this problem by checking if q->td is NULL from
blk_throtl_exit(), and remove policy deactivation as well since it's
useless.

[1] https://lore.kernel.org/all/CAHj4cs9p9H5yx+ywsb3CMUdbqGPhM+8tuBvhW=9ADiCjAqza9w@mail.gmail.com/#t

Fixes: bd9fd5be6b ("blk-throttle: fix access race during throttle policy activation")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Closes: https://lore.kernel.org/all/CAHj4cs-p-ZwBEKigBj7T6hQCOo-H68-kVwCrV6ZvRovrr9Z+HA@mail.gmail.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-17 07:27:29 -06:00
Bart Van Assche
0b507305a0 blk-mq: Fix the blk_mq_tagset_busy_iter() documentation
Commit 2dd6532e95 ("blk-mq: Drop 'reserved' arg of busy_tag_iter_fn")
removed the 'reserved' argument from tag iteration callback functions.
Bring the blk_mq_tagset_busy_iter() documentation in sync with that
change.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: John Garry <john.g.garry@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-17 07:26:29 -06:00
John Garry
da7b97ba0d block: relax atomic write boundary vs chunk size check
blk_validate_atomic_write_limits() ensures that any boundary fits into
and is aligned to any chunk size.

However, it should also be possible to fit the chunk size into any
boundary. That check is already made in
blk_stack_atomic_writes_boundary_head().

Relax the check in blk_validate_atomic_write_limits() by reusing (and
renaming) blk_stack_atomic_writes_boundary_head().

Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-16 12:29:10 -06:00
John Garry
f2d8c5a2f7 block: fix stacking of atomic writes when atomics are not supported
Atomic writes support may not always be possible when stacking devices
which support atomic writes. Such as case is a different atomic write
boundary between stacked devices (which is not supported).

In the case that atomic writes cannot supported, the top device queue HW
limits are set to 0.

However, in blk_stack_atomic_writes_limits(), we detect that we are
stacking the first bottom device by checking the top device
atomic_write_hw_max value == 0. This get confused with the case of atomic
writes not supported, above.

Make the distinction between stacking the first bottom device and no
atomics supported by initializing stacked device atomic_write_hw_max =
UINT_MAX and checking that for stacking the first bottom device.

Fixes: d7f36dc446 ("block: Support atomic writes limits for stacked devices")
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-16 12:29:10 -06:00
John Garry
bfd4037296 block: update validation of atomic writes boundary for stacked devices
In commit 63d092d1c1 ("block: use chunk_sectors when evaluating stacked
atomic write limits"), it was missed to use a chunk sectors limit check
in blk_stack_atomic_writes_boundary_head(), so update that function to
do the proper check.

Fixes: 63d092d1c1 ("block: use chunk_sectors when evaluating stacked atomic write limits")
Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-16 12:29:10 -06:00
chengkaitao
74b1db8684 block/mq-deadline: Remove the redundant rb_entry_rq in the deadline_from_pos().
In commit(fde02699c2), the "if (blk_rq_is_seq_zoned_write(rq))"
was removed, but the "rb_entry_rq(node)" and some other code were
inadvertently left behind. This patch fixed it.

Signed-off-by: chengkaitao <chengkaitao@kylinos.cn>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Li Nan <linan122@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-15 13:00:05 -06:00
Nathan Chancellor
7935b843ce md/md-llbitmap: Use DIV_ROUND_UP_SECTOR_T
When building for 32-bit platforms, there are several link (if builtin)
or modpost (if a module) errors due to dividends of type 'sector_t' in
DIV_ROUND_UP:

  arm-linux-gnueabi-ld: drivers/md/md-llbitmap.o: in function `llbitmap_resize':
  drivers/md/md-llbitmap.c:1017:(.text+0xae8): undefined reference to `__aeabi_uldivmod'
  arm-linux-gnueabi-ld: drivers/md/md-llbitmap.c:1020:(.text+0xb10): undefined reference to `__aeabi_uldivmod'
  arm-linux-gnueabi-ld: drivers/md/md-llbitmap.o: in function `llbitmap_end_discard':
  drivers/md/md-llbitmap.c:1114:(.text+0xf14): undefined reference to `__aeabi_uldivmod'
  arm-linux-gnueabi-ld: drivers/md/md-llbitmap.o: in function `llbitmap_start_discard':
  drivers/md/md-llbitmap.c:1097:(.text+0x1808): undefined reference to `__aeabi_uldivmod'
  arm-linux-gnueabi-ld: drivers/md/md-llbitmap.o: in function `llbitmap_read_sb':
  drivers/md/md-llbitmap.c:867:(.text+0x2080): undefined reference to `__aeabi_uldivmod'
  arm-linux-gnueabi-ld: drivers/md/md-llbitmap.o:drivers/md/md-llbitmap.c:895: more undefined references to `__aeabi_uldivmod' follow

Use DIV_ROUND_UP_SECTOR_T instead of DIV_ROUND_UP, which exists to
handle this exact situation.

Fixes: 5ab829f197 ("md/md-llbitmap: introduce new lockless bitmap")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 18:18:41 -06:00
Yu Kuai
a75fe12fa2 blk-mq: fix stale nr_requests documentation
The nr_requests documentation is still the removed single queue, remove
it and update to current blk-mq.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:25:56 -06:00
Yu Kuai
9784041145 blk-mq: remove blk_mq_tag_update_depth()
This helper is not used now.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:25:56 -06:00
Yu Kuai
b86433721f blk-mq: fix potential deadlock while nr_requests grown
Allocate and free sched_tags while queue is freezed can deadlock[1],
this is a long term problem, hence allocate memory before freezing
queue and free memory after queue is unfreezed.

[1] https://lore.kernel.org/all/0659ea8d-a463-47c8-9180-43c719e106eb@linux.ibm.com/
Fixes: e3a2b3f931 ("blk-mq: allow changing of queue depth through sysfs")

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:25:56 -06:00
Yu Kuai
6293e336f6 blk-mq-sched: add new parameter nr_requests in blk_mq_alloc_sched_tags()
This helper only support to allocate the default number of requests,
add a new parameter to support specific number of requests.

Prepare to fix potential deadlock in the case nr_requests grow.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:25:56 -06:00
Yu Kuai
e632004044 blk-mq: split bitmap grow and resize case in blk_mq_update_nr_requests()
No functional changes are intended, make code cleaner and prepare to fix
the grow case in following patches.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:25:56 -06:00
Yu Kuai
7f2799c546 blk-mq: cleanup shared tags case in blk_mq_update_nr_requests()
For shared tags case, all hctx->sched_tags/tags are the same, it doesn't
make sense to call into blk_mq_tag_update_depth() multiple times for the
same tags.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:25:56 -06:00
Yu Kuai
626ff4f8eb blk-mq: convert to serialize updating nr_requests with update_nr_hwq_lock
request_queue->nr_requests can be changed by:

a) switch elevator by updating nr_hw_queues
b) switch elevator by elevator sysfs attribute
c) configue queue sysfs attribute nr_requests

Current lock order is:

1) update_nr_hwq_lock, case a,b
2) freeze_queue
3) elevator_lock, case a,b,c

And update nr_requests is seriablized by elevator_lock() already,
however, in the case c, we'll have to allocate new sched_tags if
nr_requests grow, and do this with elevator_lock held and queue
freezed has the risk of deadlock.

Hence use update_nr_hwq_lock instead, make it possible to allocate
memory if tags grow, meanwhile also prevent nr_requests to be changed
concurrently.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:25:56 -06:00
Yu Kuai
b46d4c447d blk-mq: check invalid nr_requests in queue_requests_store()
queue_requests_store() is the only caller of
blk_mq_update_nr_requests(), and blk_mq_update_nr_requests() is the
only caller of blk_mq_tag_update_depth(), however, they all have
checkings for nr_requests input by user.

Make code cleaner by moving all the checkings to the top function:

1) nr_requests > reserved tags;
2) if there is elevator, 4 <= nr_requests <= 2048;
3) if elevator is none, 4 <= nr_requests <= tag_set->queue_depth;

Meanwhile, case 2 is the only case tags can grow and -ENOMEM might be
returned.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:25:56 -06:00
Yu Kuai
8bd7195fea blk-mq: remove useless checkings in blk_mq_update_nr_requests()
1) queue_requests_store() is the only caller of
blk_mq_update_nr_requests(), where queue is already freezed, no need to
check mq_freeze_depth;
2) q->tag_set must be set for request based device, and queue_is_mq() is
already checked in blk_mq_queue_attr_visible(), no need to check
q->tag_set.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:25:56 -06:00
Yu Kuai
dc1dd13d44 blk-mq: remove useless checking in queue_requests_store()
blk_mq_queue_attr_visible() already checked queue_is_mq(), no need to
check this again in queue_requests_store().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:25:56 -06:00
Caleb Sander Mateos
97e8ba31b8 ublk: consolidate nr_io_ready and nr_queues_ready
ublk_mark_io_ready() tracks whether all the ublk_device's I/Os have been
fetched by incrementing ublk_queue's nr_io_ready count and incrementing
ublk_device's nr_queues_ready count if the whole queue is ready.
Simplify the logic by just tracking the total number of fetched I/Os on
each ublk_device. When this count reaches nr_hw_queues * queue_depth,
the ublk_device is ready to receive I/O.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:24:53 -06:00
Yu Kuai
e0ed2bca7b md/raid0: convert raid0_make_request() to use bio_submit_split_bioset()
Currently, raid0_make_request() will remap the original bio to underlying
disks to prevent reordered IO. Now that bio_submit_split_bioset() will put
original bio to the head of current->bio_list, it's safe converting to use
this helper and bio will still be ordered.

CC: Jan Kara <jack@suse.cz>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:46 -06:00
Yu Kuai
b2f5974079 block: fix ordering of recursive split IO
Currently, split bio will be chained to original bio, and original bio
will be resubmitted to the tail of current->bio_list, waiting for
split bio to be issued. However, if split bio get split again, the IO
order will be messed up. This problem, on the one hand, will cause
performance degradation, especially for mdraid with large IO size; on
the other hand, will cause write errors for zoned block devices[1].

For example, in raid456 IO will first be split by max_sector from
md_submit_bio(), and then later be split again by chunksize for internal
handling:

For example, assume max_sectors is 1M, and chunksize is 512k

1) issue a 2M IO:

bio issuing: 0+2M
current->bio_list: NULL

2) md_submit_bio() split by max_sector:

bio issuing: 0+1M
current->bio_list: 1M+1M

3) chunk_aligned_read() split by chunksize:

bio issuing: 0+512k
current->bio_list: 1M+1M -> 512k+512k

4) after first bio issued, __submit_bio_noacct() will contuine issuing
next bio:

bio issuing: 1M+1M
current->bio_list: 512k+512k
bio issued: 0+512k

5) chunk_aligned_read() split by chunksize:

bio issuing: 1M+512k
current->bio_list: 512k+512k -> 1536k+512k
bio issued: 0+512k

6) no split afterwards, finally the issue order is:

0+512k -> 1M+512k -> 512k+512k -> 1536k+512k

This behaviour will cause large IO read on raid456 endup to be small
discontinuous IO in underlying disks. Fix this problem by placing split
bio to the head of current->bio_list.

Test script: test on 8 disk raid5 with 64k chunksize
dd if=/dev/md0 of=/dev/null bs=4480k iflag=direct

Test results:
Before this patch
1) iostat results:
Device            r/s     rMB/s   rrqm/s  %rrqm r_await rareq-sz  aqu-sz  %util
md0           52430.00   3276.87     0.00   0.00    0.62    64.00   32.60  80.10
sd*           4487.00    409.00  2054.00  31.40    0.82    93.34    3.68  71.20
2) blktrace G stage:
  8,0    0   486445    11.357392936   843  G   R 14071424 + 128 [dd]
  8,0    0   486451    11.357466360   843  G   R 14071168 + 128 [dd]
  8,0    0   486454    11.357515868   843  G   R 14071296 + 128 [dd]
  8,0    0   486468    11.357968099   843  G   R 14072192 + 128 [dd]
  8,0    0   486474    11.358031320   843  G   R 14071936 + 128 [dd]
  8,0    0   486480    11.358096298   843  G   R 14071552 + 128 [dd]
  8,0    0   486490    11.358303858   843  G   R 14071808 + 128 [dd]
3) io seek for sdx:
Noted io seek is the result from blktrace D stage, statistic of:
ABS((offset of next IO) - (offset + len of previous IO))

Read|Write seek
cnt 55175, zero cnt 25079
    >=(KB) .. <(KB)     : count       ratio |distribution                            |
         0 .. 1         : 25079       45.5% |########################################|
         1 .. 2         : 0            0.0% |                                        |
         2 .. 4         : 0            0.0% |                                        |
         4 .. 8         : 0            0.0% |                                        |
         8 .. 16        : 0            0.0% |                                        |
        16 .. 32        : 0            0.0% |                                        |
        32 .. 64        : 12540       22.7% |#####################                   |
        64 .. 128       : 2508         4.5% |#####                                   |
       128 .. 256       : 0            0.0% |                                        |
       256 .. 512       : 10032       18.2% |#################                       |
       512 .. 1024      : 5016         9.1% |#########                               |

After this patch:
1) iostat results:
Device            r/s     rMB/s   rrqm/s  %rrqm r_await rareq-sz  aqu-sz  %util
md0           87965.00   5271.88     0.00   0.00    0.16    61.37   14.03  90.60
sd*           6020.00    658.44  5117.00  45.95    0.44   112.00    2.68  86.50
2) blktrace G stage:
  8,0    0   206296     5.354894072   664  G   R 7156992 + 128 [dd]
  8,0    0   206305     5.355018179   664  G   R 7157248 + 128 [dd]
  8,0    0   206316     5.355204438   664  G   R 7157504 + 128 [dd]
  8,0    0   206319     5.355241048   664  G   R 7157760 + 128 [dd]
  8,0    0   206333     5.355500923   664  G   R 7158016 + 128 [dd]
  8,0    0   206344     5.355837806   664  G   R 7158272 + 128 [dd]
  8,0    0   206353     5.355960395   664  G   R 7158528 + 128 [dd]
  8,0    0   206357     5.356020772   664  G   R 7158784 + 128 [dd]
3) io seek for sdx
Read|Write seek
cnt 28644, zero cnt 21483
    >=(KB) .. <(KB)     : count       ratio |distribution                            |
         0 .. 1         : 21483       75.0% |########################################|
         1 .. 2         : 0            0.0% |                                        |
         2 .. 4         : 0            0.0% |                                        |
         4 .. 8         : 0            0.0% |                                        |
         8 .. 16        : 0            0.0% |                                        |
        16 .. 32        : 0            0.0% |                                        |
        32 .. 64        : 7161        25.0% |##############                          |

BTW, this looks like a long term problem from day one, and large
sequential IO read is pretty common case like video playing.

And even with this patch, in this test case IO is merged to at most 128k
is due to block layer plug limit BLK_PLUG_FLUSH_SIZE, increase such
limit can get even better performance. However, we'll figure out how to do
this properly later.

[1] https://lore.kernel.org/all/e40b076d-583d-406b-b223-005910a9f46f@acm.org/

Fixes: d89d87965d ("When stacked block devices are in-use (e.g. md or dm), the recursive calls")
Reported-by: Tie Ren <tieren@fnnas.com>
Closes: https://lore.kernel.org/all/7dro5o7u5t64d6bgiansesjavxcuvkq5p2pok7dtwkav7b7ape@3isfr44b6352/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:46 -06:00
Yu Kuai
0b64682e78 block: skip unnecessary checks for split bio
Lots of checks are already done while submitting this bio the first
time, and there is no need to check them again when this bio is
resubmitted after split.

Hence open code should_fail_bio() and blk_throtl_bio() that are still
necessary from submit_bio_split_bioset().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:46 -06:00
Yu Kuai
e3290419d9 blk-crypto: convert to use bio_submit_split_bioset()
Unify bio split code, prepare to fix ordering of split IO.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:46 -06:00
Yu Kuai
6529d41d87 md/md-linear: convert to use bio_submit_split_bioset()
Unify bio split code, prepare to fix reordered split IO.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:46 -06:00
Yu Kuai
9e8a5b37c9 md/raid5: convert to use bio_submit_split_bioset()
Unify bio split code, prepare to fix ordering of split IO.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:45 -06:00
Yu Kuai
6fc07785d9 md/raid10: convert read/write to use bio_submit_split_bioset()
Unify bio split code, prepare to fix ordering of split IO, the error path
is modified a bit, however no functional changes are intended:

- bio_submit_split_bioset() can fail the original bio directly
  by split error, set R10BIO_Uptodate in this case to notify
  raid_end_bio_io() that the original bio is returned already.
- set R10BIO_Uptodate and set error value to -EIO is useless now,
  for r10_bio without R10BIO_Uptodate, -EIO will be returned for
  original bio.

And discard is not handled, because discard is only split for
unaligned head and tail, and this can be considered slow path, the
reorder here does not matter much.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:45 -06:00
Yu Kuai
deeeab3028 md/raid10: add a new r10bio flag R10BIO_Returned
The new helper bio_submit_split_bioset() can failed the orginal bio on
split errors, prepare to handle this case in raid_end_bio_io().

The flag name is refer to the r1bio flag name.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:45 -06:00
Yu Kuai
a6fcc160d6 md/raid1: convert to use bio_submit_split_bioset()
Unify bio split code, and prepare to fix ordering of split IO.

Noted that bio_submit_split_bioset() can fail the original bio directly
by split error, set R1BIO_Returned in this case to notify raid_end_bio_io()
that the original bio is returned already.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:45 -06:00
Yu Kuai
5b38ee5a4a md/raid0: convert raid0_handle_discard() to use bio_submit_split_bioset()
Unify bio split code, and prepare to fix ordering of split IO

Noted commit 319ff40a54 ("md/raid0: Fix performance regression for large
sequential writes") already fix ordering of split IO by remapping bio to
underlying disks before resubmitting it, with the respect
md_submit_bio() already split it by sectors, and raid0_make_request()
will split at most once for unaligned IO. This is a bit hacky and we'll
convert this to solution in general later.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:45 -06:00
Yu Kuai
e37b5596a1 block: factor out a helper bio_submit_split_bioset()
No functional changes are intended, some drivers like mdraid will split
bio by internal processing, prepare to unify bio split codes.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:45 -06:00
Yu Kuai
06d712d297 blk-crypto: fix missing blktrace bio split events
trace_block_split() is missing, resulting in blktrace inability to catch
BIO split events and making it harder to analyze the BIO sequence.

Cc: stable@vger.kernel.org
Fixes: 488f6682c8 ("block: blk-crypto-fallback for Inline Encryption")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:45 -06:00
Yu Kuai
22f166218f md: fix mssing blktrace bio split events
If bio is split by internal handling like chunksize or badblocks, the
corresponding trace_block_split() is missing, resulting in blktrace
inability to catch BIO split events and making it harder to analyze the
BIO sequence.

Cc: stable@vger.kernel.org
Fixes: 4b1faf9316 ("block: Kill bio_pair_split()")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:45 -06:00
Yu Kuai
ea3d1f104d blk-mq: add QUEUE_FLAG_BIO_ISSUE_TIME
bio->issue_time_ns is initialized for every bio, however, it's only used
by blk-iolatency. Add a new queue_flag and only set this flag when
blk-iolatency is enabled, so that extra blk_time_get_ns() can be saved
for disks that blk-iolatency is not enabled.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:45 -06:00
Yu Kuai
1f963bdd64 block: initialize bio issue time in blk_mq_submit_bio()
bio->issue_time_ns is only used by blk-iolatency, which can only be
enabled for rq-based disk, hence it's not necessary to initialize
the time for bio-based disk.

Meanwhile, if bio is split by blk_crypto_fallback_split_bio_if_needed(),
the issue time is not initialized for new split bio, this can be fixed
as well.

Noted the next patch will optimize better that bio issue time will
only be used when blk-iolatency is really enabled by the disk.

Fixes: 488f6682c8 ("block: blk-crypto-fallback for Inline Encryption")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:45 -06:00
Yu Kuai
1733e88874 block: cleanup bio_issue
Now that bio->bi_issue is only used by blk-iolatency to get bio issue
time, replace bio_issue with u64 time directly and remove bio_issue to
make code cleaner.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-10 05:23:45 -06:00
Jens Axboe
79b24810a2 Merge tag 'md-6.18-20250909' of gitolite.kernel.org:pub/scm/linux/kernel/git/mdraid/linux into for-6.18/block
Pull MD changes from Yu Kuai:

"Redundant data is used to enhance data fault tolerance, and the storage
 method for redundant data vary depending on the RAID levels. And it's
 important to maintain the consistency of redundant data.

 Bitmap is used to record which data blocks have been synchronized and
 which ones need to be resynchronized or recovered. Each bit in the
 bitmap represents a segment of data in the array. When a bit is set,
 it indicates that the multiple redundant copies of that data segment
 may not be consistent. Data synchronization can be performed based on
 the bitmap after power failure or readding a disk. If there is no
 bitmap, a full disk synchronization is required.

 Due to known performance issues with md-bitmap and the unreasonable
 implementations:

 - self-managed IO submitting like filemap_write_page();
 - global spin_lock

 I have decided not to continue optimizing based on the current bitmap
 implementation, this new bitmap is invented without locking from IO fast
 path and can be used with fast disks.

 Key features for the new bitmap:
  - IO fastpath is lockless, if user issues lots of write IO to the same
    bitmap bit in a short time, only the first write has additional
    overhead to update bitmap bit, no additional overhead for the
    following writes;
  - support only resync or recover written data, means in the case
    creating new array or replacing with a new disk, there is no need to
    do a full disk resync/recovery;"

* tag 'md-6.18-20250909' of gitolite.kernel.org:pub/scm/linux/kernel/git/mdraid/linux: (24 commits)
  md/md-llbitmap: introduce new lockless bitmap
  md/md-bitmap: make method bitmap_ops->daemon_work optional
  md: add a new recovery_flag MD_RECOVERY_LAZY_RECOVER
  md/md-bitmap: add a new method blocks_synced() in bitmap_operations
  md/md-bitmap: add a new method skip_sync_blocks() in bitmap_operations
  md/md-bitmap: delay registration of bitmap_ops until creating bitmap
  md/md-bitmap: add a new sysfs api bitmap_type
  md: add a new mddev field 'bitmap_id'
  md/md-bitmap: support discard for bitmap ops
  md: factor out a helper raid_is_456()
  md: add a new parameter 'offset' to md_super_write()
  md/md-bitmap: introduce CONFIG_MD_BITMAP
  md: check before referencing mddev->bitmap_ops
  md/dm-raid: check before referencing mddev->bitmap_ops
  md/raid5: check before referencing mddev->bitmap_ops
  md/raid10: check before referencing mddev->bitmap_ops
  md/raid1: check before referencing mddev->bitmap_ops
  md/raid1: check bitmap before behind write
  md/md-bitmap: handle the case bitmap is not enabled before end_sync()
  md/md-bitmap: handle the case bitmap is not enabled before start_sync()
  ...
2025-09-09 11:24:03 -06:00
Keith Busch
d0d1d52231 blk-map: provide the bdev to bio if one exists
We can now safely provide a block device when extracting user pages for
driver and user passthrough commands. Set the bdev so the caller doesn't
have to do that later. This has an additional  benefit of being able to
extract P2P pages in the passthrough path.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-09 10:35:28 -06:00
Keith Busch
d57447ffb5 blk-mq-dma: bring back p2p request flags
We only need to consider data and metadata dma mapping types separately.
The request and bio integrity payload have enough flag bits to
internally track the mapping type for each. Use these so the caller
doesn't need to track them, and provide separete request and integrity
helpers to the common code. This will make it easier to scale new
mappings, like the proposed MMIO attribute, without burdening the caller
to track such things.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-09 10:33:35 -06:00
Keith Busch
05ceea5d3e blk-integrity: enable p2p source and destination
Set the extraction flags to allow p2p pages for the metadata buffer if
the block device allows it. Similar to data payloads, ensure the bio
does not use merging if we see a p2p page.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-09 10:33:27 -06:00
Keith Busch
b475272f03 iov_iter: remove iov_iter_is_aligned
No more callers.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-09-09 10:27:01 -06:00