[PATCH SRU T/U/V/W] drm: Balance error path for GEM handle allocation

[Tim Gardner]

From: Chris Wilson <chris at chris-wilson.co.uk>

BugLink: http://bugs.launchpad.net/bugs/1579610

The current error path for failure when establishing a handle for a GEM
object is unbalance, e.g. we call object_close() without calling first
object_open(). Use the typical onion structure to only undo what has
been set up prior to the error.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
(cherry picked from commit 6984128d01cf935820a0563f3a00c6623ba58109)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 drivers/gpu/drm/drm_gem.c | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index cfd7708..7490959 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -325,27 +325,32 @@ drm_gem_handle_create_tail(struct drm_file *file_priv,
 	spin_unlock(&file_priv->table_lock);
 	idr_preload_end();
 	mutex_unlock(&dev->object_name_lock);
-	if (ret < 0) {
-		drm_gem_object_handle_unreference_unlocked(obj);
-		return ret;
-	}
+	if (ret < 0)
+		goto err_unref;
+
 	*handlep = ret;
 
 	ret = drm_vma_node_allow(&obj->vma_node, file_priv->filp);
-	if (ret) {
-		drm_gem_handle_delete(file_priv, *handlep);
-		return ret;
-	}
+	if (ret)
+		goto err_remove;
 
 	if (dev->driver->gem_open_object) {
 		ret = dev->driver->gem_open_object(obj, file_priv);
-		if (ret) {
-			drm_gem_handle_delete(file_priv, *handlep);
-			return ret;
-		}
+		if (ret)
+			goto err_revoke;
 	}
 
 	return 0;
+
+err_revoke:
+	drm_vma_node_revoke(&obj->vma_node, file_priv->filp);
+err_remove:
+	spin_lock(&file_priv->table_lock);
+	idr_remove(&file_priv->object_idr, *handlep);
+	spin_unlock(&file_priv->table_lock);
+err_unref:
+	drm_gem_object_handle_unreference_unlocked(obj);
+	return ret;
 }
 
 /**
-- 
1.9.1