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authorDaniel Vetter <daniel.vetter@ffwll.ch>2018-03-22 09:02:33 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2018-03-26 17:42:06 +0200
commit3903117609f40a0bc21b8c48533ac07a574c4cdc (patch)
tree2de4db493464148719b73231d6480b081de8b1ed
parent3f07f28b9712605d1adb589344ced72e8397dc8a (diff)
downloadlinux-3903117609f40a0bc21b8c48533ac07a574c4cdc.tar.bz2
drm/gem: Document that handle_create must be the last step
It published the gem object to userspace, by that point other threads can guess the id and start using it. And gem IDs are _very_ easy to guess (it's just an idr). Since gem objects is the only thing we allow drivers to create themselves (all the kms/prime/syncobj stuff is handled by the core) no other functions seem to be in need of this clarification. Motivated by reviewing the xen-front kms driver. Cc: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180322080233.17266-1-daniel.vetter@ffwll.ch
-rw-r--r--drivers/gpu/drm/drm_gem.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 4975ba9a7bc8..4a16d7b26c89 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -436,9 +436,12 @@ err_unref:
* @obj: object to register
* @handlep: pionter to return the created handle to the caller
*
- * Create a handle for this object. This adds a handle reference
- * to the object, which includes a regular reference count. Callers
- * will likely want to dereference the object afterwards.
+ * Create a handle for this object. This adds a handle reference to the object,
+ * which includes a regular reference count. Callers will likely want to
+ * dereference the object afterwards.
+ *
+ * Since this publishes @obj to userspace it must be fully set up by this point,
+ * drivers must call this last in their buffer object creation callbacks.
*/
int drm_gem_handle_create(struct drm_file *file_priv,
struct drm_gem_object *obj,