dm: fix deadlock with request based dm and queue request_fn recursion

[pandora-kernel.git] / drivers / md / dm.c

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 502dcf7..8953630 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -755,8 +755,14 @@ static void rq_completed(struct mapped_device *md, int rw, int run_queue)
        if (!md_in_flight(md))
                wake_up(&md->wait);
 
+       /*
+        * Run this off this callpath, as drivers could invoke end_io while
+        * inside their request_fn (and holding the queue lock). Calling
+        * back into ->request_fn() could deadlock attempting to grab the
+        * queue lock again.
+        */
        if (run_queue)
-               blk_run_queue(md->queue);
+               blk_run_queue_async(md->queue);
 
        /*
         * dm_put() must be at the end of this function. See the comment above