drm/prime: add exported buffers to current fprivs imported buffer list (v2)

If userspace attempts to import a buffer it exported on the same device,
we need to return the same GEM handle for it, not a new handle pointing
at the same GEM object.

v2: move removals into a single fn, no need to set to NULL. (Chris Wilson)

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 20dbf2c45385..f546ff98a114 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -68,6 +68,7 @@ int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 {
 	struct drm_gem_object *obj;
 	void *buf;
+	int ret;
 
 	obj = drm_gem_object_lookup(dev, file_priv, handle);
 	if (!obj)
@@ -100,6 +101,17 @@ int drm_gem_prime_handle_to_fd(struct drm_device *dev,
 		obj->export_dma_buf = buf;
 		*prime_fd = dma_buf_fd(buf, flags);
 	}
+	/* if we've exported this buffer the cheat and add it to the import list
+	 * so we get the correct handle back
+	 */
+	ret = drm_prime_add_imported_buf_handle(&file_priv->prime,
+			obj->export_dma_buf, handle);
+	if (ret) {
+		drm_gem_object_unreference_unlocked(obj);
+		mutex_unlock(&file_priv->prime.lock);
+		return ret;
+	}
+
 	mutex_unlock(&file_priv->prime.lock);
 	return 0;
 }