When one thread waits for another, we must use memory barriers, otherwise the CPU may reorder memory accesses.
Signed-off-by: Mikulas Patocka <[email protected]> Cc: [email protected] --- 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 [email protected] https://listman.redhat.com/mailman/listinfo/dm-devel
