On Mon, Jan 04, 2016 at 10:11:00AM +0000, Chris Wilson wrote:
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 chris@chris-wilson.co.uk
drivers/gpu/drm/drm_gem.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)
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);
Hmm. Yeah, handle_count is protected by object_name_lock, so this looks better here rather than within the spinlocked section.
Patch looks sane: Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com
/* * 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;
-- 2.6.4
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