To ensure that neither the GEM object nor the DRM device goes away while
a GEM object exported through dma-buf is still accessible, take a
reference to both the GEM object and the DRM device at export time. The
dma-buf release handler already releases the GEM object (which resulted
in a refcount underflow) and now also releases the DRM device.
Fixes: 6ad11bc3a0b8 ("staging: drm/omap: dmabuf/prime support")
Signed-off-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
---
drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
index 79dfded9613c..88ad723b3044 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
@@ -75,10 +75,11 @@ static void omap_gem_unmap_dma_buf(struct
dma_buf_attachment *attachment,
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()..
- */
+ struct drm_device *dev = obj->dev;
+
+ /* Release references taken by omap_gem_prime_export(). */
drm_gem_object_unreference_unlocked(obj);
+ drm_dev_ref(dev);
}
@@ -184,13 +185,21 @@ struct dma_buf *omap_gem_prime_export(struct drm_device
*dev,
struct drm_gem_object *obj, int flags)
{
DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+ struct dma_buf *dma_buf;
exp_info.ops = &omap_dmabuf_ops;
exp_info.size = obj->size;
exp_info.flags = flags;
exp_info.priv = obj;
- return dma_buf_export(&exp_info);
+ dma_buf = dma_buf_export(&exp_info);
+ if (IS_ERR(dma_buf))
+ return dma_buf;
+
+ drm_dev_ref(dev);
+ drm_gem_object_reference(obj);
+
+ return dma_buf;
}
/*
-----------------------------------------------------------------------------
--
Regards,
Laurent Pinchart
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