From 1e9bb8808ac11094d711d20d580e7b45a4992d0c Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Tue, 22 Mar 2011 08:35:35 +0100 Subject: 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 Signed-off-by: Jens Axboe --- drivers/md/dm.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'drivers/md/dm.c') diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 88820704a191..0cf68b478878 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -477,7 +477,8 @@ static void start_io_acct(struct dm_io *io) 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 @@ static void end_io_acct(struct dm_io *io) * 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 */ -- cgit v1.2.3