drm/i915: Avoid taking the mutex for dropping the refcnt upon creation

After allocation a handle for the fresh object, we know that we can
safely drop the refcnt without triggering a free so we do not need the
mutex. Strangely, this mutex acquisition is the one that appears on
driver profiles.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 32ff571672b4..942e4b351cdd 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -244,12 +244,17 @@ i915_gem_create_ioctl(struct drm_device *dev, void *data,
                 return -ENOMEM;
 
         ret = drm_gem_handle_create(file_priv, obj, &handle);
-        /* drop reference from allocate - handle holds it now */
-        drm_gem_object_unreference_unlocked(obj);
         if (ret) {
+                drm_gem_object_release(obj);
+                i915_gem_info_remove_obj(dev->dev_private, obj->size);
+                kfree(obj);
                 return ret;
         }
 
+        /* drop reference from allocate - handle holds it now */
+        drm_gem_object_unreference(obj);
+        trace_i915_gem_object_create(obj);
+
         args->handle = handle;
         return 0;
 }
@@ -4380,8 +4385,6 @@ struct drm_gem_object * i915_gem_alloc_object(struct drm_device *dev,
         INIT_LIST_HEAD(&obj->gpu_write_list);
         obj->madv = I915_MADV_WILLNEED;
 
-        trace_i915_gem_object_create(&obj->base);
-
         return &obj->base;
 }