At least with dm-mq this patch reduces the number of multipath_busy()
calls while scsi_dh_activate() is in progress from a few million to
a few thousand.
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
---
drivers/md/dm-mpath.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index dd80af2..dd66653 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -343,12 +343,15 @@ static void multipath_init_per_bio_data(struct bio *bio, struct dm_mpath_io **mp
* Path selection
*-----------------------------------------------*/
+/* Returns a value > 0 if path group initialization is still in progress. */
static int __pg_init_all_paths(struct multipath *m)
{
struct pgpath *pgpath;
unsigned long pg_init_delay = 0;
- if (atomic_read(&m->pg_init_in_progress) || test_bit(MPATHF_PG_INIT_DISABLED, &m->flags))
+ if (atomic_read(&m->pg_init_in_progress))
+ return 1;
+ if (test_bit(MPATHF_PG_INIT_DISABLED, &m->flags))
return 0;
atomic_inc(&m->pg_init_count);
--
2.10.0
--
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