From: Chris Wilson Date: Mon, 4 Jan 2016 10:11:00 +0000 (+0000) Subject: drm: Only bump object-reference count when adding first handle X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=98a8883ad419128493b8cfab3982d58785deabda;p=linux-beck.git drm: Only bump object-reference count when adding first handle We only need a single reference count for all handles (i.e. non-zero obj->handle_count) and so can trim a few atomic operations by only taking the reference on the first handle and dropping it after the last. Signed-off-by: Chris Wilson Reviewed-by: Ville Syrjälä Link: http://patchwork.freedesktop.org/patch/msgid/1451902261-25380-2-git-send-email-chris@chris-wilson.co.uk Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index a08176debc0e..ad955d7c99fd 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -220,6 +220,9 @@ static void drm_gem_object_exported_dma_buf_free(struct drm_gem_object *obj) static void drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj) { + struct drm_device *dev = obj->dev; + bool final = false; + if (WARN_ON(obj->handle_count == 0)) return; @@ -229,14 +232,16 @@ drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj) * checked for a name */ - mutex_lock(&obj->dev->object_name_lock); + mutex_lock(&dev->object_name_lock); if (--obj->handle_count == 0) { drm_gem_object_handle_free(obj); drm_gem_object_exported_dma_buf_free(obj); + final = true; } - mutex_unlock(&obj->dev->object_name_lock); + mutex_unlock(&dev->object_name_lock); - drm_gem_object_unreference_unlocked(obj); + if (final) + drm_gem_object_unreference_unlocked(obj); } /** @@ -329,6 +334,8 @@ drm_gem_handle_create_tail(struct drm_file *file_priv, int ret; WARN_ON(!mutex_is_locked(&dev->object_name_lock)); + if (obj->handle_count++ == 0) + drm_gem_object_reference(obj); /* * Get the user-visible handle using idr. Preload and perform @@ -338,10 +345,10 @@ drm_gem_handle_create_tail(struct drm_file *file_priv, spin_lock(&file_priv->table_lock); ret = idr_alloc(&file_priv->object_idr, obj, 1, 0, GFP_NOWAIT); - drm_gem_object_reference(obj); - obj->handle_count++; + spin_unlock(&file_priv->table_lock); idr_preload_end(); + mutex_unlock(&dev->object_name_lock); if (ret < 0) goto err_unref;