From: Mike Snitzer snitzer@redhat.com
commit b879f915bc48a18d4f4462729192435bb0f17052 upstream.
Record the start_time for a bio but defer the starting block core's IO accounting until after IO is submitted using bio_start_io_acct_time().
This approach avoids the need to mess around with any of the individual IO stats in response to a bio_split() that follows bio submission.
Reported-by: Bud Brown bubrown@redhat.com Reviewed-by: Christoph Hellwig hch@lst.de Cc: stable@vger.kernel.org Depends-on: e45c47d1f94e ("block: add bio_start_io_acct_time() to control start_time") Signed-off-by: Mike Snitzer snitzer@redhat.com Link: https://lore.kernel.org/r/20220128155841.39644-4-snitzer@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/dm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -489,7 +489,7 @@ static void start_io_acct(struct dm_io * struct mapped_device *md = io->md; struct bio *bio = io->orig_bio;
- io->start_time = bio_start_io_acct(bio); + bio_start_io_acct_time(bio, io->start_time); if (unlikely(dm_stats_used(&md->stats))) dm_stats_account_io(&md->stats, bio_data_dir(bio), bio->bi_iter.bi_sector, bio_sectors(bio), @@ -535,7 +535,7 @@ static struct dm_io *alloc_io(struct map io->md = md; spin_lock_init(&io->endio_lock);
- start_io_acct(io); + io->start_time = jiffies;
return io; } @@ -1550,6 +1550,7 @@ static void __split_and_process_bio(stru submit_bio_noacct(bio); } } + start_io_acct(ci.io);
/* drop the extra reference count */ dm_io_dec_pending(ci.io, errno_to_blk_status(error));