drm/prime: drop reference on imported dma-buf come from gem

Increasing ref counts of both dma-buf and gem for imported dma-buf come from gem
makes memory leak. release function of dma-buf cannot be called because f_count
of dma-buf increased by importing gem and gem ref count cannot be decrease
because of exported dma-buf.

So I add dma_buf_put() for imported gem come from its own gem into each drivers
having prime_import and prime_export capabilities. With this, only gem ref
count is increased if importing gem exported from gem of same driver.

Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Kyungmin.park <kyungmin.park@samsung.com>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Rob Clark <rob.clark@linaro.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_prime.c b/drivers/gpu/drm/nouveau/nouveau_prime.c
index 3543fec2355e..b8e05ae38212 100644
--- a/drivers/gpu/drm/nouveau/nouveau_prime.c
+++ b/drivers/gpu/drm/nouveau/nouveau_prime.c
@@ -193,6 +193,7 @@ struct drm_gem_object *nouveau_gem_prime_import(struct drm_device *dev,
 		if (nvbo->gem) {
 			if (nvbo->gem->dev == dev) {
 				drm_gem_object_reference(nvbo->gem);
+				dma_buf_put(dma_buf);
 				return nvbo->gem;
 			}
 		}