Commit 9da0e06a authored by Luca Ceresoli's avatar Luca Ceresoli
Browse files

drm/bridge: deprecate of_drm_find_bridge() 



of_drm_find_bridge() does not increment the returned bridge
refcount. of_drm_find_and_get_bridge() is to be used as a replacement.

Suggested-by: default avatarMaxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/dri-devel/20250319-stylish-lime-mongoose-0a18ad@houat/


Reviewed-by: default avatarMaxime Ripard <mripard@kernel.org>
Link: https://patch.msgid.link/20251216-drm-bridge-alloc-getput-drm_of_find_bridge-v3-2-b5165fab8058@bootlin.com


Signed-off-by: default avatarLuca Ceresoli <luca.ceresoli@bootlin.com>
parent 293a8fd7

drivers/gpu/drm/drm_bridge.c

+18 −4
Original line number Diff line number Diff line
@@ -361,7 +361,7 @@ EXPORT_SYMBOL(__devm_drm_bridge_alloc); 
 * @bridge: bridge control structure

 *

 * Add the given bridge to the global list of bridges, where they can be

 * found by users via of_drm_find_bridge().

 * found by users via of_drm_find_and_get_bridge().

 *

 * The bridge to be added must have been allocated by

 * devm_drm_bridge_alloc().
@@ -422,9 +422,9 @@ EXPORT_SYMBOL(devm_drm_bridge_add); 
 * @bridge: bridge control structure

 *

 * Remove the given bridge from the global list of registered bridges, so

 * it won't be found by users via of_drm_find_bridge(), and add it to the

 * lingering bridge list, to keep track of it until its allocated memory is

 * eventually freed.

 * it won't be found by users via of_drm_find_and_get_bridge(), and add it

 * to the lingering bridge list, to keep track of it until its allocated

 * memory is eventually freed.

 */

void drm_bridge_remove(struct drm_bridge *bridge)

{
@@ -1510,6 +1510,20 @@ EXPORT_SYMBOL(of_drm_find_and_get_bridge); 
 *

 * @np: device node

 *

 * This function is deprecated. Convert to of_drm_find_and_get_bridge()

 * instead for proper refcounting.

 *

 * The bridge returned by this function is not refcounted. This is

 * dangerous because the bridge might be deallocated even before the caller

 * has a chance to use it. To use this function you have to do one of:

 * - get a reference with drm_bridge_get() as soon as possible to

 *   minimize the race window, and then drm_bridge_put() when no longer

 *   using the pointer

 * - not call drm_bridge_get() or drm_bridge_put() at all, which used to

 *   be the correct practice before dynamic bridge lifetime was introduced

 * - again, convert to of_drm_find_and_get_bridge(), which is the only safe

 *   thing to do

 *

 * RETURNS:

 * drm_bridge control struct on success, NULL on failure

 */