[PATCH 26/41] dm: fix locking context in queue_io()

From: Kiyoshi Ueda

Now queue_io() is called from dec_pending(), which may be called with
interrupts disabled, so queue_io() must not enable interrupts
unconditionally and must save/restore the current interrupts status.

Signed-off-by: Kiyoshi Ueda
Signed-off-by: Jun'ichi Nomura
Signed-off-by: Tejun Heo
---
drivers/md/dm.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 2011704..cd2f7e7 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -512,9 +512,11 @@ static void end_io_acct(struct dm_io *io)
*/
static void queue_io(struct mapped_device *md, struct bio *bio)
{
- spin_lock_irq(&md->deferred_lock);
+ unsigned long flags;
+
+ spin_lock_irqsave(&md->deferred_lock, flags);
bio_list_add(&md->deferred, bio);
- spin_unlock_irq(&md->deferred_lock);
+ spin_unlock_irqrestore(&md->deferred_lock, flags);
queue_work(md->wq, &md->work);
}

--
1.7.1