From 3903117609f40a0bc21b8c48533ac07a574c4cdc Mon Sep 17 00:00:00 2001 From: Daniel Vetter Date: Thu, 22 Mar 2018 09:02:33 +0100 Subject: 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 Reviewed-by: Oleksandr Andrushchenko Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20180322080233.17266-1-daniel.vetter@ffwll.ch --- drivers/gpu/drm/drm_gem.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'drivers') 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, -- cgit v1.2.3