block: fold blk_max_size_offset into get_max_io_size

Now that blk_max_size_offset has a single caller left, fold it into that
and clean up the naming convention for the local variables there.

Signe

block: fold blk_max_size_offset into get_max_io_size

Now that blk_max_size_offset has a single caller left, fold it into that
and clean up the naming convention for the local variables there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220614090934.570632-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: cleanup variable naming in get_max_io_size

get_max_io_size has a very odd choice of variables names and
initialization patterns. Switch to more descriptive names and more
clear initializatio

block: cleanup variable naming in get_max_io_size

get_max_io_size has a very odd choice of variables names and
initialization patterns. Switch to more descriptive names and more
clear initialization of them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220614090934.570632-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: open code blk_max_size_offset in blk_rq_get_max_sectors

blk_rq_get_max_sectors always uses q->limits.chunk_sectors as the
chunk_sectors argument, and already checks for max_sectors through th

block: open code blk_max_size_offset in blk_rq_get_max_sectors

blk_rq_get_max_sectors always uses q->limits.chunk_sectors as the
chunk_sectors argument, and already checks for max_sectors through the
call to blk_queue_get_max_sectors. That means much of
blk_max_size_offset is not needed and open coding it simplifies the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220614090934.570632-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block/merge: count bytes instead of sectors

Individual bv_len's may not be a sector size.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Joh

block/merge: count bytes instead of sectors

Individual bv_len's may not be a sector size.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220610195830.3574005-7-kbusch@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: don't merge across cgroup boundaries if blkcg is enabled

blk-iocost and iolatency are cgroup aware rq-qos policies but they didn't
disable merges across different cgroups. This obviously can

block: don't merge across cgroup boundaries if blkcg is enabled

blk-iocost and iolatency are cgroup aware rq-qos policies but they didn't
disable merges across different cgroups. This obviously can lead to
accounting and control errors but more importantly to priority inversions -
e.g. an IO which belongs to a higher priority cgroup or IO class may end up
getting throttled incorrectly because it gets merged to an IO issued from a
low priority cgroup.

Fix it by adding blk_cgroup_mergeable() which is called from merge paths and
rejects cross-cgroup and cross-issue_as_root merges.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: d70675121546 ("block: introduce blk-iolatency io controller")
Cc: stable@vger.kernel.org # v4.19+
Cc: Josef Bacik <jbacik@fb.com>
Link: https://lore.kernel.org/r/Yi/eE/6zFNyWJ+qd@slm.duckdns.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: ensure plug merging checks the correct queue at least once

Song reports that a RAID rebuild workload runs much slower recently,
and it is seeing a lot less merging than it did previously. The

block: ensure plug merging checks the correct queue at least once

Song reports that a RAID rebuild workload runs much slower recently,
and it is seeing a lot less merging than it did previously. The reason
is that a previous commit reduced the amount of work we do for plug
merging. RAID rebuild interleaves requests between disks, so a last-entry
check in plug merging always misses a merge opportunity since we always
find a different disk than what we are looking for.

Modify the logic such that it's still a one-hit cache, but ensure that
we check enough to find the right target before giving up.

Fixes: d38a9c04c0d5 ("block: only check previous entry for plug merge attempt")
Reported-and-tested-by: Song Liu <song@kernel.org>
Reviewed-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: remove the per-bio/request write hint

With the NVMe support for this gone, there are no consumers of these hints
left, so remove them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: htt

block: remove the per-bio/request write hint

With the NVMe support for this gone, there are no consumers of these hints
left, so remove them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220304175556.407719-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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scsi: block: Remove REQ_OP_WRITE_SAME support

No more users of REQ_OP_WRITE_SAME or drivers implementing it are left,
so remove the infrastructure.

[mkp: fold in and tweak sysfs reporting fix]

Lin

scsi: block: Remove REQ_OP_WRITE_SAME support

No more users of REQ_OP_WRITE_SAME or drivers implementing it are left,
so remove the infrastructure.

[mkp: fold in and tweak sysfs reporting fix]

Link: https://lore.kernel.org/r/20220209082828.2629273-8-hch@lst.de
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

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block: throttle split bio in case of iops limit

Commit 111be8839817 ("block-throttle: avoid double charge") marks bio as
BIO_THROTTLED unconditionally if __blk_throtl_bio() is called on this bio,
th

block: throttle split bio in case of iops limit

Commit 111be8839817 ("block-throttle: avoid double charge") marks bio as
BIO_THROTTLED unconditionally if __blk_throtl_bio() is called on this bio,
then this bio won't be called into __blk_throtl_bio() any more. This way
is to avoid double charge in case of bio splitting. It is reasonable for
read/write throughput limit, but not reasonable for IOPS limit because
block layer provides io accounting against split bio.

Chunguang Xu has already observed this issue and fixed it in commit
4f1e9630afe6 ("blk-throtl: optimize IOPS throttle for large IO scenarios").
However, that patch only covers bio splitting in __blk_queue_split(), and
we have other kind of bio splitting, such as bio_split() &
submit_bio_noacct() and other ways.

This patch tries to fix the issue in one generic way by always charging
the bio for iops limit in blk_throtl_bio(). This way is reasonable:
re-submission & fast-cloned bio is charged if it is submitted to same
disk/queue, and BIO_THROTTLED will be cleared if bio->bi_bdev is changed.

This new approach can get much more smooth/stable iops limit compared with
commit 4f1e9630afe6 ("blk-throtl: optimize IOPS throttle for large IO
scenarios") since that commit can't throttle current split bios actually.

Also this way won't cause new double bio iops charge in
blk_throtl_dispatch_work_fn() in which blk_throtl_bio() won't be called
any more.

Reported-by: Ning Li <lining2020x@163.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Chunguang Xu <brookxu@tencent.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-7-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: don't check ->rq_disk in merges

There is a 1:1 relationship between request_queues and gendisks now, so
no need for these extra checks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed

block: don't check ->rq_disk in merges

There is a 1:1 relationship between request_queues and gendisks now, so
no need for these extra checks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: don't include <linux/part_stat.h> in blk.h

Not needed, shift it into the source files that need it instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/2021

block: don't include <linux/part_stat.h> in blk.h

Not needed, shift it into the source files that need it instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: don't include blk-mq-sched.h in blk.h

No needed, shift it into the source files that need it instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/2021112318

block: don't include blk-mq-sched.h in blk.h

No needed, shift it into the source files that need it instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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blk-mq: simplify the plug handling in blk_mq_submit_bio

blk_mq_submit_bio has two different plug cases, one that uses full
plugging and a limited plugging one.

The limited plugging case is only use

blk-mq: simplify the plug handling in blk_mq_submit_bio

blk_mq_submit_bio has two different plug cases, one that uses full
plugging and a limited plugging one.

The limited plugging case is only used for a corner case that does
not matter in real life:

- no ->commit_rqs (so not NVMe)
- no shared tags (so not SCSI)
- not rotational (so no old disk or floppy driver)
- must have multiple queues (so no eMMC)

Remove the limited merging case and all the related junk to simplify
blk_mq_submit_bio and the functions called from it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123160443.1315598-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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blk-mq: only try to run plug merge if request has same queue with incoming bio

It is obvious that io merge can't be done between two different queues, so
just try to run io merge in case of same que

blk-mq: only try to run plug merge if request has same queue with incoming bio

It is obvious that io merge can't be done between two different queues, so
just try to run io merge in case of same queue.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211102133502.3619184-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: convert leftovers to bdev_get_queue

Convert bdev->bd_disk->queue to bdev_get_queue(), which is faster.
Apparently, there are a few such spots in block that got lost during
rebases.

Reviewed-

block: convert leftovers to bdev_get_queue

Convert bdev->bd_disk->queue to bdev_get_queue(), which is faster.
Apparently, there are a few such spots in block that got lost during
rebases.

Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: change plugging to use a singly linked list

Use a singly linked list for the blk_plug. This saves 8 bytes in the
blk_plug struct, and makes for faster list manipulations than doubly
linked li

block: change plugging to use a singly linked list

Use a singly linked list for the blk_plug. This saves 8 bytes in the
blk_plug struct, and makes for faster list manipulations than doubly
linked lists. As we don't use the doubly linked lists for anything,
singly linked is just fine.

This yields a bump in default (merging enabled) performance from 7.0
to 7.1M IOPS, and ~7.5M IOPS with merging disabled.

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

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block: return whether or not to unplug through boolean

Instead of returning the same queue request through a request pointer,
use a boolean to accomplish the same.

Reviewed-by: Christoph Hellwig <h

block: return whether or not to unplug through boolean

Instead of returning the same queue request through a request pointer,
use a boolean to accomplish the same.

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

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block: handle fast path of bio splitting inline

The fast path is no splitting needed. Separate the handling into a
check part we can inline, and an out-of-line handling path if we do
need to split.

block: handle fast path of bio splitting inline

The fast path is no splitting needed. Separate the handling into a
check part we can inline, and an out-of-line handling path if we do
need to split.

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

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block: rename REQ_HIPRI to REQ_POLLED

Unlike the RWF_HIPRI userspace ABI which is intentionally kept vague,
the bio flag is specific to the polling implementation, so rename and
document it properly

block: rename REQ_HIPRI to REQ_POLLED

Unlike the RWF_HIPRI userspace ABI which is intentionally kept vague,
the bio flag is specific to the polling implementation, so rename and
document it properly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Link: https://lore.kernel.org/r/20211012111226.760968-12-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: only check previous entry for plug merge attempt

Currently we scan the entire plug list, which is potentially very
expensive. In an IOPS bound workload, we can drive about 5.6M IOPS with
merg

block: only check previous entry for plug merge attempt

Currently we scan the entire plug list, which is potentially very
expensive. In an IOPS bound workload, we can drive about 5.6M IOPS with
merging enabled, and profiling shows that the plug merge check is the
(by far) most expensive thing we're doing:

Overhead Command Shared Object Symbol
+ 20.89% io_uring [kernel.vmlinux] [k] blk_attempt_plug_merge
+ 4.98% io_uring [kernel.vmlinux] [k] io_submit_sqes
+ 4.78% io_uring [kernel.vmlinux] [k] blkdev_direct_IO
+ 4.61% io_uring [kernel.vmlinux] [k] blk_mq_submit_bio

Instead of browsing the whole list, just check the previously inserted
entry. That is enough for a naive merge check and will catch most cases,
and for devices that need full merging, the IO scheduler attached to
such devices will do that anyway. The plug merge is meant to be an
inexpensive check to avoid getting a request, but if we repeatedly
scan the list for every single insert, it is very much not a cheap
check.

With this patch, the workload instead runs at ~7.0M IOPS, providing
a 25% improvement. Disabling merging entirely yields another 5%
improvement.

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

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block: move bio_get_{first,last}_bvec out of bio.h

bio_get_first_bvec and bio_get_last_bvec are only used in blk-merge.c,
so move them there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: htt

block: move bio_get_{first,last}_bvec out of bio.h

bio_get_first_bvec and bio_get_last_bvec are only used in blk-merge.c,
so move them there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211012161804.991559-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: move blk-throtl fast path inline

Even if no policies are defined, we spend ~2% of the total IO time
checking. Move the fast path inline.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Je

block: move blk-throtl fast path inline

Even if no policies are defined, we spend ~2% of the total IO time
checking. Move the fast path inline.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: move integrity handling out of <linux/blkdev.h>

Split the integrity/metadata handling definitions out into a new header.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes T

block: move integrity handling out of <linux/blkdev.h>

Split the integrity/metadata handling definitions out into a new header.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210920123328.1399408-17-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: move a few merge helpers out of <linux/blkdev.h>

These are block-layer internal helpers, so move them to block/blk.h and
block/blk-merge.c. Also update a comment a bit to use better grammar.

block: move a few merge helpers out of <linux/blkdev.h>

These are block-layer internal helpers, so move them to block/blk.h and
block/blk-merge.c. Also update a comment a bit to use better grammar.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20210920123328.1399408-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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block: don't merge across cgroup boundaries if blkcg is enabled

commit 6b2b04590b51aa4cf395fcd185ce439cab5961dc upstream.

blk-iocost and iolatency are cgroup aware rq-qos policies but they didn't
d

block: don't merge across cgroup boundaries if blkcg is enabled

commit 6b2b04590b51aa4cf395fcd185ce439cab5961dc upstream.

blk-iocost and iolatency are cgroup aware rq-qos policies but they didn't
disable merges across different cgroups. This obviously can lead to
accounting and control errors but more importantly to priority inversions -
e.g. an IO which belongs to a higher priority cgroup or IO class may end up
getting throttled incorrectly because it gets merged to an IO issued from a
low priority cgroup.

Fix it by adding blk_cgroup_mergeable() which is called from merge paths and
rejects cross-cgroup and cross-issue_as_root merges.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: d70675121546 ("block: introduce blk-iolatency io controller")
Cc: stable@vger.kernel.org # v4.19+
Cc: Josef Bacik <jbacik@fb.com>
Link: https://lore.kernel.org/r/Yi/eE/6zFNyWJ+qd@slm.duckdns.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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