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block: fix non-atomic access to genhd inflight structures

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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>
This commit is contained in:
Shaohua Li
2011-03-22 08:35:35 +01:00
committed by Jens Axboe
parent 5e84ea3a9c
commit 1e9bb8808a
3 changed files with 12 additions and 10 deletions
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7
drivers/md/dm.c
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@@ -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 */