block: fix non-atomic access to genhd inflight structures
After the stack plugging introduction, these are called lockless.
Ensure that the counters are updated atomically.
Signed-off-by: Shaohua Li<shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 8882070..0cf68b4 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -477,7 +477,8 @@
cpu = part_stat_lock();
part_round_stats(cpu, &dm_disk(md)->part0);
part_stat_unlock();
- dm_disk(md)->part0.in_flight[rw] = atomic_inc_return(&md->pending[rw]);
+ atomic_set(&dm_disk(md)->part0.in_flight[rw],
+ atomic_inc_return(&md->pending[rw]));
}
static void end_io_acct(struct dm_io *io)
@@ -497,8 +498,8 @@
* After this is decremented the bio must not be touched if it is
* a flush.
*/
- dm_disk(md)->part0.in_flight[rw] = pending =
- atomic_dec_return(&md->pending[rw]);
+ pending = atomic_dec_return(&md->pending[rw]);
+ atomic_set(&dm_disk(md)->part0.in_flight[rw], pending);
pending += atomic_read(&md->pending[rw^0x1]);
/* nudge anyone waiting on suspend queue */