When one thread waits for another, we must use memory barriers, otherwise
the CPU may reorder memory accesses.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/md/dm.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
Index: linux-2.6/drivers/md/dm.c
===================================================================
--- linux-2.6.orig/drivers/md/dm.c 2022-02-18 17:04:34.000000000 +0100
+++ linux-2.6/drivers/md/dm.c 2022-02-18 17:15:11.000000000 +0100
@@ -506,6 +506,8 @@ static void end_io_acct(struct mapped_de
bio->bi_iter.bi_sector, bio_sectors(bio),
true, duration, stats_aux);
+ smp_wmb();
+
bio_end_io_acct(bio, start_time);
/* nudge anyone waiting on suspend queue */
@@ -2170,9 +2172,8 @@ static int dm_wait_for_completion(struct
int r = 0;
if (!queue_is_mq(md->queue))
- return dm_wait_for_bios_completion(md, task_state);
-
- while (true) {
+ r = dm_wait_for_bios_completion(md, task_state);
+ else while (true) {
if (!blk_mq_queue_inflight(md->queue))
break;
@@ -2184,6 +2185,8 @@ static int dm_wait_for_completion(struct
msleep(5);
}
+ smp_rmb();
+
return r;
}
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://listman.redhat.com/mailman/listinfo/dm-devel
