diff options
author | Ming Lei <ming.lei@redhat.com> | 2022-06-24 17:12:53 +0300 |
---|---|---|
committer | Mike Snitzer <snitzer@kernel.org> | 2022-06-29 21:17:16 +0300 |
commit | 444fe04f7a5a7991daa1a8fc3680670ac87fc2ce (patch) | |
tree | 4ee9ffed1c6199432d695e061affda10a2271498 /drivers | |
parent | e810cb78bc4b4febeac451a0d823ca68622cd86b (diff) | |
download | linux-444fe04f7a5a7991daa1a8fc3680670ac87fc2ce.tar.xz |
dm: improve BLK_STS_DM_REQUEUE and BLK_STS_AGAIN handling
If either BLK_STS_DM_REQUEUE or BLK_STS_AGAIN is returned for POLLED
io, we requeue the original bio into deferred list and kick md->wq to
re-submit it to block layer.
Improve the handling in the following way:
1) Factor out dm_handle_requeue() for handling dm_io requeue.
2) Unify handling for BLK_STS_DM_REQUEUE and BLK_STS_AGAIN: clear
REQ_POLLED for BLK_STS_DM_REQUEUE too, for the sake of simplicity,
given BLK_STS_DM_REQUEUE is very unusual.
3) Queue md->wq explicitly in dm_handle_requeue(), so requeue handling
becomes more robust.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/md/dm.c | 70 |
1 files changed, 45 insertions, 25 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 84929bd137d0..c987f9ad24a4 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -880,22 +880,41 @@ static int __noflush_suspending(struct mapped_device *md) return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); } -static void dm_io_complete(struct dm_io *io) +/* + * Return true if the dm_io's original bio is requeued. + * io->status is updated with error if requeue disallowed. + */ +static bool dm_handle_requeue(struct dm_io *io) { - blk_status_t io_error; - struct mapped_device *md = io->md; struct bio *bio = io->split_bio ? io->split_bio : io->orig_bio; + bool handle_requeue = (io->status == BLK_STS_DM_REQUEUE); + bool handle_polled_eagain = ((io->status == BLK_STS_AGAIN) && + (bio->bi_opf & REQ_POLLED)); + struct mapped_device *md = io->md; + bool requeued = false; - if (io->status == BLK_STS_DM_REQUEUE) { + if (handle_requeue || handle_polled_eagain) { unsigned long flags; + + if (bio->bi_opf & REQ_POLLED) { + /* + * Upper layer won't help us poll split bio + * (io->orig_bio may only reflect a subset of the + * pre-split original) so clear REQ_POLLED. + */ + bio_clear_polled(bio); + } + /* - * Target requested pushing back the I/O. + * Target requested pushing back the I/O or + * polled IO hit BLK_STS_AGAIN. */ spin_lock_irqsave(&md->deferred_lock, flags); - if (__noflush_suspending(md) && - !WARN_ON_ONCE(dm_is_zone_write(md, bio))) { - /* NOTE early return due to BLK_STS_DM_REQUEUE below */ + if ((__noflush_suspending(md) && + !WARN_ON_ONCE(dm_is_zone_write(md, bio))) || + handle_polled_eagain) { bio_list_add_head(&md->deferred, bio); + requeued = true; } else { /* * noflush suspend was interrupted or this is @@ -906,6 +925,21 @@ static void dm_io_complete(struct dm_io *io) spin_unlock_irqrestore(&md->deferred_lock, flags); } + if (requeued) + queue_work(md->wq, &md->work); + + return requeued; +} + +static void dm_io_complete(struct dm_io *io) +{ + struct bio *bio = io->split_bio ? io->split_bio : io->orig_bio; + struct mapped_device *md = io->md; + blk_status_t io_error; + bool requeued; + + requeued = dm_handle_requeue(io); + io_error = io->status; if (dm_io_flagged(io, DM_IO_ACCOUNTED)) dm_end_io_acct(io); @@ -925,23 +959,9 @@ static void dm_io_complete(struct dm_io *io) if (unlikely(wq_has_sleeper(&md->wait))) wake_up(&md->wait); - if (io_error == BLK_STS_DM_REQUEUE || io_error == BLK_STS_AGAIN) { - if (bio->bi_opf & REQ_POLLED) { - /* - * Upper layer won't help us poll split bio (io->orig_bio - * may only reflect a subset of the pre-split original) - * so clear REQ_POLLED in case of requeue. - */ - bio_clear_polled(bio); - if (io_error == BLK_STS_AGAIN) { - /* io_uring doesn't handle BLK_STS_AGAIN (yet) */ - queue_io(md, bio); - return; - } - } - if (io_error == BLK_STS_DM_REQUEUE) - return; - } + /* Return early if the original bio was requeued */ + if (requeued) + return; if (bio_is_flush_with_data(bio)) { /* |