drm/gem: handlecount isn't really a kref so don't make it one.

There were lots of places being inconsistent since handle count
looked like a kref but it really wasn't.

Fix this my just making handle count an atomic on the object,
and have it increase the normal object kref.

Now i915/radeon/nouveau drivers can drop the normal reference on
userspace object creation, and have the handle hold it.

This patch fixes a memory leak or corruption on unload, because
the driver had no way of knowing if a handle had been actually
added for this object, and the fbcon object needed to know this
to clean itself up properly.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 5 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index cf4ffbee1c00..4cdf74264ee8 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -136,14 +136,12 @@ 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_unreference_unlocked(obj);
                 return ret;
         }
 
-        /* Sink the floating reference from kref_init(handlecount) */
-        drm_gem_object_handle_unreference_unlocked(obj);
-
         args->handle = handle;
         return 0;
 }
diff --git a/drivers/gpu/drm/i915/intel_fb.c b/drivers/gpu/drm/i915/intel_fb.c
index 7bdc96256bf5..56ad9df2ccb5 100644
--- a/drivers/gpu/drm/i915/intel_fb.c
+++ b/drivers/gpu/drm/i915/intel_fb.c
@@ -237,8 +237,10 @@ int intel_fbdev_destroy(struct drm_device *dev,
         drm_fb_helper_fini(&ifbdev->helper);
 
         drm_framebuffer_cleanup(&ifb->base);
-        if (ifb->obj)
+        if (ifb->obj) {
+                drm_gem_object_handle_unreference(ifb->obj);
                 drm_gem_object_unreference(ifb->obj);
+        }
 
         return 0;
 }