drm: Wake up all lock waiters when the master disappears.

Currently only one waiter is woken up, leaving other waiters
hanging waiting for the DRM lock.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/gpu/drm/drm_bufs.c b/drivers/gpu/drm/drm_bufs.c
index 72c667f..12715d3 100644
--- a/drivers/gpu/drm/drm_bufs.c
+++ b/drivers/gpu/drm/drm_bufs.c
@@ -420,7 +420,7 @@
 				dev->sigdata.lock = NULL;
 			master->lock.hw_lock = NULL;   /* SHM removed */
 			master->lock.file_priv = NULL;
-			wake_up_interruptible(&master->lock.lock_queue);
+			wake_up_interruptible_all(&master->lock.lock_queue);
 		}
 		break;
 	case _DRM_AGP: