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Commit c488dd20 authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Tomi Valkeinen
Browse files

drm: omapdrm: Take GEM object reference when exporting dmabuf 



To ensure that neither the GEM object nor the DRM device goes away while
a GEM object exported through dma-buf is still accessible, references
must be taken to both the GEM object and the DRM device at export time.
The dma-buf release handler already releases the GEM object, but the
export handler doesn't take a corresponding reference, which results in
a refcount underflow.

Fix this by replacing the custom implementation by
drm_gem_dmabuf_export() and drm_gem_dmabuf_release() that handle
reference counting for us.

Fixes: 6ad11bc3 ("staging: drm/omap: dmabuf/prime support")
Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
parent 97817fd4

drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c

+2 −12
Original line number Diff line number Diff line
@@ -72,16 +72,6 @@ static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment, 
	kfree(sg);

}



static void omap_gem_dmabuf_release(struct dma_buf *buffer)

{

	struct drm_gem_object *obj = buffer->priv;

	/* release reference that was taken when dmabuf was exported

	 * in omap_gem_prime_set()..

	 */

	drm_gem_object_unreference_unlocked(obj);

}





static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,

		enum dma_data_direction dir)

{
@@ -157,7 +147,7 @@ static int omap_gem_dmabuf_mmap(struct dma_buf *buffer, 
static struct dma_buf_ops omap_dmabuf_ops = {

	.map_dma_buf = omap_gem_map_dma_buf,

	.unmap_dma_buf = omap_gem_unmap_dma_buf,

	.release = omap_gem_dmabuf_release,

	.release = drm_gem_dmabuf_release,

	.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,

	.end_cpu_access = omap_gem_dmabuf_end_cpu_access,

	.map_atomic = omap_gem_dmabuf_kmap_atomic,
@@ -177,7 +167,7 @@ struct dma_buf *omap_gem_prime_export(struct drm_device *dev, 
	exp_info.flags = flags;

	exp_info.priv = obj;



	return dma_buf_export(&exp_info);

	return drm_gem_dmabuf_export(dev, &exp_info);

}



/* -----------------------------------------------------------------------------