drm/nvc0/fifo: prevent races between clients updating playlists

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nouveau/core/engine/fifo/nvc0.c b/drivers/gpu/drm/nouveau/core/engine/fifo/nvc0.c
index 4d4a6b905370..1613193e21e6 100644
--- a/drivers/gpu/drm/nouveau/core/engine/fifo/nvc0.c
+++ b/drivers/gpu/drm/nouveau/core/engine/fifo/nvc0.c
@@ -71,6 +71,7 @@ nvc0_fifo_playlist_update(struct nvc0_fifo_priv *priv)
         struct nouveau_gpuobj *cur;
         int i, p;
 
+        mutex_lock(&nv_subdev(priv)->mutex);
         cur = priv->playlist[priv->cur_playlist];
         priv->cur_playlist = !priv->cur_playlist;
 
@@ -87,6 +88,7 @@ nvc0_fifo_playlist_update(struct nvc0_fifo_priv *priv)
         nv_wr32(priv, 0x002274, 0x01f00000 | (p >> 3));
         if (!nv_wait(priv, 0x00227c, 0x00100000, 0x00000000))
                 nv_error(priv, "playlist update failed\n");
+        mutex_unlock(&nv_subdev(priv)->mutex);
 }
 
 static int