From: Michael S. Tsirkin <mst@redhat.com>
Date: Mon, 5 Dec 2016 20:36:56 +0000 (+0200)
Subject: drm/virtio: fix lock context imbalance
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=f862e60f8d52dae33c9f72afc20fab691a89f0bd;p=linux-beck.git

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 974f9410474b..abfc54a18f1a 100644
--- 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);