drm/prime: Take a ref on the drm_dev when exporting a dma_buf
dma_buf may live a long time, longer than the last direct user of the
driver. We already hold a reference to the owner module (that prevents
the object code from disappearing), but there is no reference to the
drm_dev - so the pointers to the driver backend themselves may vanish.
v2: Resist temptation to fix the bug in armada_gem.c not setting the
correct flags on the exported dma-buf (it should pass the flags through
and not be arbitrarily setting O_RDWR).
Use a common wrapper for exporting the dmabuf and acquiring the
reference to the drm_device.
Testcase: igt/vgem_basic/unload
Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Petri Latvala <petri.latvala@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Tested-by: Petri Latvala <petri.latvala@intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161005122145.1507-2-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 80907b3..875df8d 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -284,18 +284,46 @@
}
/**
+ * drm_gem_dmabuf_export - dma_buf export implementation for GEM
+ * @dma_buf: buffer to be exported
+ *
+ * This wraps dma_buf_export() for use by generic GEM drivers that are using
+ * drm_gem_dmabuf_release(). In addition to calling dma_buf_export(), we take
+ * a reference to the drm_device which is released by drm_gem_dmabuf_release().
+ *
+ * Returns the new dmabuf.
+ */
+struct dma_buf *drm_gem_dmabuf_export(struct drm_device *dev,
+ struct dma_buf_export_info *exp_info)
+{
+ struct dma_buf *dma_buf;
+
+ dma_buf = dma_buf_export(exp_info);
+ if (!IS_ERR(dma_buf))
+ drm_dev_ref(dev);
+
+ return dma_buf;
+}
+EXPORT_SYMBOL(drm_gem_dmabuf_export);
+
+/**
* drm_gem_dmabuf_release - dma_buf release implementation for GEM
* @dma_buf: buffer to be released
*
* Generic release function for dma_bufs exported as PRIME buffers. GEM drivers
* must use this in their dma_buf ops structure as the release callback.
+ * drm_gem_dmabuf_release() should be used in conjunction with
+ * drm_gem_dmabuf_export().
*/
void drm_gem_dmabuf_release(struct dma_buf *dma_buf)
{
struct drm_gem_object *obj = dma_buf->priv;
+ struct drm_device *dev = obj->dev;
/* drop the reference on the export fd holds */
drm_gem_object_unreference_unlocked(obj);
+
+ drm_dev_unref(dev);
}
EXPORT_SYMBOL(drm_gem_dmabuf_release);
@@ -412,7 +440,7 @@
if (dev->driver->gem_prime_res_obj)
exp_info.resv = dev->driver->gem_prime_res_obj(obj);
- return dma_buf_export(&exp_info);
+ return drm_gem_dmabuf_export(dev, &exp_info);
}
EXPORT_SYMBOL(drm_gem_prime_export);