Commit f524d9c9 authored by Mike Snitzer's avatar Mike Snitzer Committed by Jens Axboe
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dm: revert partial fix for redundant bio-based IO accounting 



Reverts a1e1cb72 ("dm: fix redundant IO accounting for bios that
need splitting") because it was too narrow in scope (only addressed
redundant 'sectors[]' accounting and not ios, nsecs[], etc).

Cc: stable@vger.kernel.org
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220128155841.39644-3-snitzer@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent e45c47d1

drivers/md/dm.c

+0 −15
Original line number Diff line number Diff line
@@ -1442,9 +1442,6 @@ static void init_clone_info(struct clone_info *ci, struct mapped_device *md, 
	ci->sector = bio->bi_iter.bi_sector;

}



#define __dm_part_stat_sub(part, field, subnd)	\

	(part_stat_get(part, field) -= (subnd))



/*

 * Entry point to split a bio into clones and submit them to the targets.

 */
@@ -1480,18 +1477,6 @@ static void __split_and_process_bio(struct mapped_device *md, 
						  GFP_NOIO, &md->queue->bio_split);

			ci.io->orig_bio = b;



			/*

			 * Adjust IO stats for each split, otherwise upon queue

			 * reentry there will be redundant IO accounting.

			 * NOTE: this is a stop-gap fix, a proper fix involves

			 * significant refactoring of DM core's bio splitting

			 * (by eliminating DM's splitting and just using bio_split)

			 */

			part_stat_lock();

			__dm_part_stat_sub(dm_disk(md)->part0,

					   sectors[op_stat_group(bio_op(bio))], ci.sector_count);

			part_stat_unlock();



			bio_chain(b, bio);

			trace_block_split(b, bio->bi_iter.bi_sector);

			submit_bio_noacct(bio);