The elevator is only used for file system requests, which are stopped in
del_gendisk.  Move disabling the elevator and freeing the scheduler tags
to the end of del_gendisk instead of doing that work in disk_release and
blk_cleanup_queue to avoid a use after free on q->tag_set from
disk_release as the tag_set might not be alive at that point.

Move the blk_qos_exit call as well, as it just depends on the elevator
exit and would be the only reason to keep the not exactly cheap queue
freeze in disk_release.

Fixes: e155b0c2 ("blk-mq: Use shared tags for shared sbitmap support")
Reported-by: syzbot+3e3f419f4a7816471838@syzkaller.appspotmail.com
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Tested-by: syzbot+3e3f419f4a7816471838@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20220614074827.458955-2-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

We want to have a valid live gendisk to call ->poll and not just a
request_queue, so call the right helper.

Fixes: 3e08773c ("block: switch polling to be bio based")
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220523124302.526186-1-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

submit_bio uses some extremely convoluted checks and confusing comments
to only account REQ_OP_READ/REQ_OP_WRITE comments.  Just switch to the
plain obvious checks instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220516063654.2782792-1-hch@lst.de
[axboe: fixup WRITE -> REQ_OP_WRITE]
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Print the start sector and length separately instead of the combined
value to help with debugging.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDamien Le Moal <damien.lemoal@opensource.wdc.com>
Link: https://lore.kernel.org/r/20220504143355.568660-1-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

This reverts commit daaca352.

Commit daaca352 ("block: release rq qos structures for queue without
disk") is only needed for v5.15~v5.17, and isn't needed for v5.18, so
revert it.
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220426024936.3321341-1-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Export IO accounting interfaces in terms of block_device now that
gendisk has become more internal to block core.

Rename __part_{start,end}_io_acct's first argument from part to bdev.
Rename __part_{start,end}_io_acct to bdev_{start,end}_io_acct and
export them.  Remove disk_{start,end}_io_acct and update caller (zram)
to use bdev_{start,end}_io_acct.

DM can now be updated to use bdev_{start,end}_io_acct.
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20220418022733.56168-2-snitzer@kernel.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Secure erase is a very different operation from discard in that it is
a data integrity operation vs hint.  Fully split the limits and helper
infrastructure to make the separation more clear.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd]
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> [nifs2]
Acked-by: Jaegeuk Kim <jaegeuk@kernel.org> [f2fs]
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Acked-by: NChao Yu <chao@kernel.org>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-27-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Just use a non-zero max_discard_sectors as an indicator for discard
support, similar to what is done for write zeroes.

The only places where needs special attention is the RAID5 driver,
which must clear discard support for security reasons by default,
even if the default stacking rules would allow for it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd]
Acked-by: Jan Höppner <hoeppner@linux.ibm.com> [s390]
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-25-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

blkcg_init_queue() may add rq qos structures to request queue, previously
blk_cleanup_queue() calls rq_qos_exit() to release them, but commit
8e141f9e ("block: drain file system I/O on del_gendisk")
moves rq_qos_exit() into del_gendisk(), so memory leak is caused
because queues may not have disk, such as un-present scsi luns, nvme
admin queue, ...

Fixes the issue by adding rq_qos_exit() to blk_cleanup_queue() back.

BTW, v5.18 won't need this patch any more since we move
blkcg_init_queue()/blkcg_exit_queue() into disk allocation/release
handler, and patches have been in for-5.18/block.

Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Fixes: 8e141f9e ("block: drain file system I/O on del_gendisk")
Reported-by: syzbot+b42749a851a47a0f581b@syzkaller.appspotmail.com
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220314043018.177141-1-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Prepare for supporting IO polling for bio-based driver.

Add ->poll_bio callback so that bio-based driver can provide their own
logic for polling bio.

Also fix ->submit_bio_bio typo in comment block above
__submit_bio_noacct.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

After blk_cleanup_queue() returns, disk may not be released yet, so
probably bio may still be submitted and ->q_usage_counter may be
touched, so far this way seems safe, but not good from API's viewpoint.

Move the release q_usage_counter into blk_queue_release().
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220308055200.735835-12-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

blkcg works on FS bio level, so it is reasonable to make both blkcg and
gendisk sharing same lifetime. Meantime there won't be any FS IO when
releasing disk, so safe to move blkcg initialization/destroy into disk
allocation/release handler

Long term, we can move blkcg into gendisk completely.
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220308055200.735835-10-hch@lst.de
[axboe: fixup missing blk-cgroup.h include]
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Use the %pg format specifier instead of the stack hungry bdevname
function, and remove handle_bad_sector given that it is not pointless.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220304180105.409765-3-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Don't use a WARN_ON when printing a potentially user triggered
condition.  Also don't print the partno when the block device name
already includes it, and use the %pg specifier to simplify printing
the block device name.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220304180105.409765-2-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

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.deReviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Various block drivers call blk_set_queue_dying to mark a disk as dead due
to surprise removal events, but since commit 8e141f9e that doesn't
work given that the GD_DEAD flag needs to be set to stop I/O.

Replace the driver calls to blk_set_queue_dying with a new (and properly
documented) blk_mark_disk_dead API, and fold blk_set_queue_dying into the
only remaining caller.

Fixes: 8e141f9e ("block: drain file system I/O on del_gendisk")
Reported-by: NMarkus Blöchl <markus.bloechl@ipetronik.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NSagi Grimberg <sagi@grimberg.me>
Link: https://lore.kernel.org/r/20220217075231.1140-1-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Now submit_bio_checks() is only called by submit_bio_noacct(), so merge
it into submit_bio_noacct().
Suggested-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-6-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

The bio has been checked already before throttling, so no need to check
it again before dispatching it from throttle queue.

Add a helper of submit_bio_noacct_nocheck() for this purpose.
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220216044514.2903784-5-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

submit_bio_checks() won't be called outside of block/blk-core.c any more
since commit 9d497e29 ("block: don't protect submit_bio_checks by
q_usage_counter"), so mark it as one local helper.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-4-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

blk_crypto_bio_prep() is called for both bio based and blk-mq drivers,
so move it out of blk-mq.c, then we can unify this kind of handling.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-3-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

It is more clean & readable to check bio when starting to submit it,
instead of just before calling ->submit_bio() or blk_mq_submit_bio().

Also it provides us chance to optimize bio submission without checking
bio.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220216044514.2903784-2-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Partition include/linux/blk-cgroup.h into two parts: one is public part,
the other is block layer private part.

Suggested by Christoph Hellwig.
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220211101149.2368042-4-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

q->blkg_list is only used by blkcg code, so move it into
blkcg_init_queue.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220211101149.2368042-3-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Change the user visible return value for BLK_STS_OFFLINE to -ENODEV, which
is more descriptive than existing -EIO.
Signed-off-by: NSong Liu <song@kernel.org>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220203192827.1370270-3-song@kernel.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Currently, drivers reports BLK_STS_IOERR for devices that are not full
online or being removed. This behavior could cause confusion for users,
as they are not really I/O errors from the device.

Solve this issue with a new state BLK_STS_OFFLINE, which reports "device
offline error" in dmesg instead of "I/O error".

EIO is intentionally kept to not change user visible return value.
Signed-off-by: NSong Liu <song@kernel.org>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20220203192827.1370270-2-song@kernel.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Rename blk_flush_plug to __blk_flush_plug and add a wrapper that includes
the NULL check instead of open coding that check everywhere.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220127070549.1377856-2-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

bio_start_io_acct_time() interface is like bio_start_io_acct() that
allows start_time to be passed in. This gives drivers the ability to
defer starting accounting until after IO is issued (but possibily not
entirely due to bio splitting).
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220128155841.39644-2-snitzer@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Commit cc9c884d ("block: call submit_bio_checks under q_usage_counter")
uses q_usage_counter to protect submit_bio_checks for avoiding IO after
disk is deleted by del_gendisk().

Turns out the protection isn't necessary, because once
blk_mq_freeze_queue_wait() in del_gendisk() returns:

1) all in-flight IO has been done

2) all new IO will be failed in __bio_queue_enter() because
   q_usage_counter is dead, and GD_DEAD is set

3) both disk and request queue instance are safe since caller of
submit_bio() guarantees that the disk can't be closed.

Once submit_bio_checks() needn't the protection of q_usage_counter, we can
move submit_bio_checks before calling blk_mq_submit_bio() and
->submit_bio(). With this change, we needn't to throttle queue with
holding one allocated request, then precise driver tag or request won't be
wasted in throttling. Meantime we can unify the bio check for both bio
based and request based driver.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220104134223.590803-1-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

This reverts commit cb2ac291.

Alex and the kernel test robot report that this causes a significant
performance regression with BFQ. I can reproduce that result, so let's
revert this one as we're close to -rc6 and we there's no point in trying
to rush a fix.

Link: https://lore.kernel.org/linux-block/1639853092.524jxfaem2.none@localhost/
Link: https://lore.kernel.org/lkml/20211219141852.GH14057@xsang-OptiPlex-9020/Reported-by: NAlex Xu (Hello71) <alex_y_xu@yahoo.ca>
Reported-by: Nkernel test robot <oliver.sang@intel.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Dexuan reports that he's seeing spikes of very heavy CPU utilization when
running 24 disks and using the 'none' scheduler. This happens off the
sched restart path, because SCSI requires the queue to be restarted async,
and hence we're hammering on mod_delayed_work_on() to ensure that the work
item gets run appropriately.

Avoid hammering on the timer and just use queue_work_on() if no delay
has been specified.
Reported-and-tested-by: NDexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/linux-block/BYAPR21MB1270C598ED214C0490F47400BF719@BYAPR21MB1270.namprd21.prod.outlook.com/Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

In case of BLK_MQ_F_BLOCKING, per-hctx srcu is used to protect dispatch
critical area. However, this srcu instance stays at the end of hctx, and
it often takes standalone cacheline, often cold.

Inside srcu_read_lock() and srcu_read_unlock(), WRITE is always done on
the indirect percpu variable which is allocated from heap instead of
being embedded, srcu->srcu_idx is read only in srcu_read_lock(). It
doesn't matter if srcu structure stays in hctx or request queue.

So switch to per-request-queue srcu for protecting dispatch, and this
way simplifies quiesce a lot, not mention quiesce is always done on the
request queue wide.
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211203131534.3668411-3-ming.lei@redhat.comSigned-off-by: NJens Axboe <axboe@kernel.dk>

Not needed, shift it into the source files that need it instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-9-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

No needed, shift it into the source files that need it instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211123185312.1432157-5-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

The only user of the io_context for IO is BFQ, yet we put the checking
and logic of it into the normal IO path.

Put the creation into blk_mq_sched_assign_ioc(), and have BFQ use that
helper.
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

All request based code is in the blk-mq files now.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-12-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

This function is only used by the request completion path.  Factor out
a blk_status_to_str to keep blk_errors private in blk-core.c.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-11-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

blk_dump_rq_flags deals with a request, so move it to blk-mq.c.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-10-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

These are only used for request based I/O, so move them where they are
used.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-9-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Keep all the request based code together.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-8-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

blk_rq_init deals with a request structure, so move it to blk-mq.c
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20211117061404.331732-7-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>