Commit 0ab30b40 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm: eliminate copying of dm_io fields in dm_io_dec_pending 



There is no need for dm_io_dec_pending() to copy dm_io fields
anymore now that DM provides its own pending_io counters again.

The race documented in commit d208b894 ("dm: fix mempool NULL
pointer race when completing IO") no longer exists now that block
core's in_flight counters aren't used to signal all dm_io is
complete.

Also, rename {start,end}_io_acct to dm_{start,end}_io_acct.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 0cdb90f0

drivers/md/dm.c

+7 −12
Original line number Diff line number Diff line
@@ -518,15 +518,14 @@ static void dm_io_acct(bool end, struct mapped_device *md, struct bio *bio, 
		bio->bi_iter.bi_size = bi_size;

}



static void start_io_acct(struct dm_io *io)

static void dm_start_io_acct(struct dm_io *io)

{

	dm_io_acct(false, io->md, io->orig_bio, io->start_time, &io->stats_aux);

}



static void end_io_acct(struct mapped_device *md, struct bio *bio,

			unsigned long start_time, struct dm_stats_aux *stats_aux)

static void dm_end_io_acct(struct dm_io *io)

{

	dm_io_acct(true, md, bio, start_time, stats_aux);

	dm_io_acct(true, io->md, io->orig_bio, io->start_time, &io->stats_aux);

}



static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio)
@@ -808,8 +807,6 @@ void dm_io_dec_pending(struct dm_io *io, blk_status_t error) 
	blk_status_t io_error;

	struct bio *bio;

	struct mapped_device *md = io->md;

	unsigned long start_time = 0;

	struct dm_stats_aux stats_aux;



	/* Push-back supersedes any I/O errors */

	if (unlikely(error)) {
@@ -841,10 +838,8 @@ void dm_io_dec_pending(struct dm_io *io, blk_status_t error) 
		}



		io_error = io->status;

		start_time = io->start_time;

		stats_aux = io->stats_aux;

		dm_end_io_acct(io);

		free_io(md, io);

		end_io_acct(md, bio, start_time, &stats_aux);

		smp_wmb();

		this_cpu_dec(*md->pending_io);
@@ -1444,8 +1439,8 @@ static void __split_and_process_bio(struct mapped_device *md, 
			 * so that it gets handled *after* bios already submitted

			 * have been completely processed.

			 * We take a clone of the original to store in

			 * ci.io->orig_bio to be used by end_io_acct() and

			 * for dec_pending to use for completion handling.

			 * ci.io->orig_bio to be used by dm_end_io_acct() and

			 * for dm_io_dec_pending() to use for completion handling.

			 */

			struct bio *b = bio_split(bio, bio_sectors(bio) - ci.sector_count,

						  GFP_NOIO, &md->queue->bio_split);
@@ -1456,7 +1451,7 @@ static void __split_and_process_bio(struct mapped_device *md, 
			submit_bio_noacct(bio);

		}

	}

	start_io_acct(ci.io);

	dm_start_io_acct(ci.io);



	/* drop the extra reference count */

	dm_io_dec_pending(ci.io, errno_to_blk_status(error));