Commit 69cea0d4 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm mpath: changes from initial m->flags locking audit 



Fix locking in slow-paths where m->lock should be taken.

Signed-off-by: default avatarMike Snitzer <snitzer@rredhat.com>
parent 11ba4688

drivers/md/dm-mpath.c

+13 −3
Original line number Diff line number Diff line
@@ -335,6 +335,8 @@ static int pg_init_all_paths(struct multipath *m) 


static void __switch_pg(struct multipath *m, struct priority_group *pg)

{

	lockdep_assert_held(&m->lock);



	m->current_pg = pg;



	/* Must we initialise the PG first, and queue I/O till it's ready? */
@@ -382,7 +384,9 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) 
	unsigned bypassed = 1;



	if (!atomic_read(&m->nr_valid_paths)) {

		spin_lock_irqsave(&m->lock, flags);

		clear_bit(MPATHF_QUEUE_IO, &m->flags);

		spin_unlock_irqrestore(&m->lock, flags);

		goto failed;

	}
@@ -422,8 +426,11 @@ static struct pgpath *choose_pgpath(struct multipath *m, size_t nr_bytes) 
				continue;

			pgpath = choose_path_in_pg(m, pg, nr_bytes);

			if (!IS_ERR_OR_NULL(pgpath)) {

				if (!bypassed)

				if (!bypassed) {

					spin_lock_irqsave(&m->lock, flags);

					set_bit(MPATHF_PG_INIT_DELAY_RETRY, &m->flags);

					spin_unlock_irqrestore(&m->lock, flags);

				}

				return pgpath;

			}

		}
@@ -1662,9 +1669,9 @@ static int multipath_end_io_bio(struct dm_target *ti, struct bio *clone, 


	spin_lock_irqsave(&m->lock, flags);

	bio_list_add(&m->queued_bios, clone);

	spin_unlock_irqrestore(&m->lock, flags);

	if (!test_bit(MPATHF_QUEUE_IO, &m->flags))

		queue_work(kmultipathd, &m->process_queued_bios);

	spin_unlock_irqrestore(&m->lock, flags);



	r = DM_ENDIO_INCOMPLETE;

done:
@@ -1938,6 +1945,7 @@ static int multipath_prepare_ioctl(struct dm_target *ti, 
{

	struct multipath *m = ti->private;

	struct pgpath *current_pgpath;

	unsigned long flags;

	int r;



	current_pgpath = READ_ONCE(m->current_pgpath);
@@ -1965,8 +1973,10 @@ static int multipath_prepare_ioctl(struct dm_target *ti, 
			/* Path status changed, redo selection */

			(void) choose_pgpath(m, 0);

		}

		spin_lock_irqsave(&m->lock, flags);

		if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags))

			pg_init_all_paths(m);

			(void) __pg_init_all_paths(m);

		spin_unlock_irqrestore(&m->lock, flags);

		dm_table_run_md_queue_async(m->ti->table);

		process_queued_io_list(m);

	}