drm/virtio: fix lock context imbalance

When virtio_gpu_free_vbufs exits due to list empty, it does not
drop the free_vbufs lock that it took.
list empty is not expected to happen anyway, but it can't hurt to fix
this and drop the lock.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 974f9410474b1fb1c18279b231db0c36e64b9632..abfc54a18f1af624645f9860147a75dd17c49284 100644 (file)
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -109,8 +109,10 @@ void virtio_gpu_free_vbufs(struct virtio_gpu_device *vgdev)
 
        spin_lock(&vgdev->free_vbufs_lock);
        for (i = 0; i < count; i++) {
-               if (WARN_ON(list_empty(&vgdev->free_vbufs)))
+               if (WARN_ON(list_empty(&vgdev->free_vbufs))) {
+                       spin_unlock(&vgdev->free_vbufs_lock);
                        return;
+               }
                vbuf = list_first_entry(&vgdev->free_vbufs,
                                        struct virtio_gpu_vbuffer, list);
                list_del(&vbuf->list);