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Commit 39031176 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

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: default avatarOleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180322080233.17266-1-daniel.vetter@ffwll.ch
parent 3f07f28b

drivers/gpu/drm/drm_gem.c

+6 −3
Original line number Diff line number Diff line
@@ -436,9 +436,12 @@ drm_gem_handle_create_tail(struct drm_file *file_priv, 
 * @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,