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drm: Only bump object-reference count when adding first handle

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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>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1451902261-25380-2-git-send-email-chris@chris-wilson.co.uk
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Chris Wilson 2016-01-04 10:11:00 +00:00 committed by Daniel Vetter
parent 6984128d01
commit 98a8883ad4
1 changed files with 12 additions and 5 deletions
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17
drivers/gpu/drm/drm_gem.c
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@ -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;