drm: introduce drm_gem_object_[handle_]unreference_unlocked

This patch introduces the drm_gem_object_unreference_unlocked
and drm_gem_object_handle_unreference_unlocked functions that
do not require holding struct_mutex.

drm_gem_object_unreference_unlocked calls the new
->gem_free_object_unlocked entry point if available, and
otherwise just takes struct_mutex and just calls ->gem_free_object

Signed-off-by: Luca Barbieri <luca@luca-barbieri.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 25 insertions, 3 deletions

diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index ffac157fb5b2..4a3c4e441027 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -801,6 +801,7 @@ struct drm_driver {
          */
         int (*gem_init_object) (struct drm_gem_object *obj);
         void (*gem_free_object) (struct drm_gem_object *obj);
+        void (*gem_free_object_unlocked) (struct drm_gem_object *obj);
 
         /* vga arb irq handler */
         void (*vgaarb_irq)(struct drm_device *dev, bool state);
@@ -1427,6 +1428,7 @@ extern void drm_sysfs_connector_remove(struct drm_connector *connector);
 int drm_gem_init(struct drm_device *dev);
 void drm_gem_destroy(struct drm_device *dev);
 void drm_gem_object_free(struct kref *kref);
+void drm_gem_object_free_unlocked(struct kref *kref);
 struct drm_gem_object *drm_gem_object_alloc(struct drm_device *dev,
                                             size_t size);
 void drm_gem_object_handle_free(struct kref *kref);
@@ -1443,10 +1445,15 @@ drm_gem_object_reference(struct drm_gem_object *obj)
 static inline void
 drm_gem_object_unreference(struct drm_gem_object *obj)
 {
-        if (obj == NULL)
-                return;
+        if (obj != NULL)
+                kref_put(&obj->refcount, drm_gem_object_free);
+}
 
-        kref_put(&obj->refcount, drm_gem_object_free);
+static inline void
+drm_gem_object_unreference_unlocked(struct drm_gem_object *obj)
+{
+        if (obj != NULL)
+                kref_put(&obj->refcount, drm_gem_object_free_unlocked);
 }
 
 int drm_gem_handle_create(struct drm_file *file_priv,
@@ -1475,6 +1482,21 @@ drm_gem_object_handle_unreference(struct drm_gem_object *obj)
         drm_gem_object_unreference(obj);
 }
 
+static inline void
+drm_gem_object_handle_unreference_unlocked(struct drm_gem_object *obj)
+{
+        if (obj == NULL)
+                return;
+
+        /*
+        * Must bump handle count first as this may be the last
+        * ref, in which case the object would disappear before we
+        * checked for a name
+        */
+        kref_put(&obj->handlecount, drm_gem_object_handle_free);
+        drm_gem_object_unreference_unlocked(obj);
+}
+
 struct drm_gem_object *drm_gem_object_lookup(struct drm_device *dev,
                                              struct drm_file *filp,
                                              u32 handle);