drm: drm_fops.c unlock missing on error path

drm_open_helper() from drm_fops.c had a missing mutex_unlock in a error
path.

This was caught by smatch (http://repo.or.cz/w/smatch.git/).  Compile
tested.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index e13cb62bbaee..09a3571c9908 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -274,6 +274,7 @@ static int drm_open_helper(struct inode *inode, struct file *filp,
                 /* create a new master */
                 priv->minor->master = drm_master_create(priv->minor);
                 if (!priv->minor->master) {
+                        mutex_unlock(&dev->struct_mutex);
                         ret = -ENOMEM;
                         goto out_free;
                 }