[PATCH] dm: dm_suspend locking fix

dm_suspend(): Stop holding the read lock around the while loop that
waits for pending io to complete.

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 00d299a4fcd42b07a10b785f38ecdef61bcbbc3d..e7a4aa84775e7f1d07f54228044253f0d34664d8 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -715,15 +715,13 @@ int dm_suspend(struct mapped_device *md)
        }
 
        set_bit(DMF_BLOCK_IO, &md->flags);
+       add_wait_queue(&md->wait, &wait);
        up_write(&md->lock);
 
        /*
         * Then we wait for the already mapped ios to
         * complete.
         */
-       down_read(&md->lock);
-
-       add_wait_queue(&md->wait, &wait);
        while (1) {
                set_current_state(TASK_INTERRUPTIBLE);
 
@@ -734,11 +732,11 @@ int dm_suspend(struct mapped_device *md)
        }
 
        current->state = TASK_RUNNING;
-       remove_wait_queue(&md->wait, &wait);
-       up_read(&md->lock);
 
-       /* set_bit is atomic */
+       down_write(&md->lock);
+       remove_wait_queue(&md->wait, &wait);
        set_bit(DMF_SUSPENDED, &md->flags);
+       up_write(&md->lock);
 
        return 0;
 }