[PATCH] drm: Take ownership of the dmabuf->obj when exporting

[Chris Wilson]

Currently the reference for the dmabuf->obj is incremented for the
dmabuf in drm_gem_prime_handle_to_fd() (at the high level userspace
interface), but is released in drm_gem_dmabuf_release() (the lowlevel
handler). Improve the symmetry of the dmabuf->obj ownership by acquiring
the reference in drm_gem_dmabuf_export(). This makes it easier to use
the prime functions directly.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/drm_prime.c       | 9 +++++----
 drivers/gpu/drm/vgem/vgem_fence.c | 1 -
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index b22a94dd7b53..5ef946d5a32d 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -300,8 +300,11 @@ struct dma_buf *drm_gem_dmabuf_export(struct drm_device 
*dev,
        struct dma_buf *dma_buf;

        dma_buf = dma_buf_export(exp_info);
-       if (!IS_ERR(dma_buf))
-               drm_dev_ref(dev);
+       if (IS_ERR(dma_buf))
+               return dma_buf;
+
+       drm_dev_ref(dev);
+       drm_gem_object_reference(exp_info->priv);

        return dma_buf;
 }
@@ -472,8 +475,6 @@ static struct dma_buf *export_and_register_object(struct 
drm_device *dev,
         */
        obj->dma_buf = dmabuf;
        get_dma_buf(obj->dma_buf);
-       /* Grab a new ref since the callers is now used by the dma-buf */
-       drm_gem_object_reference(obj);

        return dmabuf;
 }
diff --git a/drivers/gpu/drm/vgem/vgem_fence.c 
b/drivers/gpu/drm/vgem/vgem_fence.c
index 9cb00a5d5d08..da25dfe7b80e 100644
--- a/drivers/gpu/drm/vgem/vgem_fence.c
+++ b/drivers/gpu/drm/vgem/vgem_fence.c
@@ -126,7 +126,6 @@ static int attach_dmabuf(struct drm_device *dev,
                return PTR_ERR(dmabuf);

        obj->dma_buf = dmabuf;
-       drm_gem_object_reference(obj);
        return 0;
 }

-- 
2.11.0