of_drm_find_bridge() does not increment the returned bridge refcount. of_drm_get_bridge() is to be used as a replacement.
Suggested-by: Maxime Ripard <[email protected]> Link: https://lore.kernel.org/dri-devel/20250319-stylish-lime-mongoose-0a18ad@houat/ Signed-off-by: Luca Ceresoli <[email protected]> --- Changes in v2: - expand comment to mention why this function is dangerous and what users should do about refcounting --- drivers/gpu/drm/drm_bridge.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 367b7a3d8aa3..21a84715d221 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -299,7 +299,7 @@ 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_get_bridge(). * * The bridge to be added must have been allocated by * devm_drm_bridge_alloc(). @@ -360,7 +360,7 @@ 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 + * it won't be found by users via of_drm_get_bridge(), and add it to the * lingering bridge list, to keep track of it until its allocated memory is * eventually freed. */ @@ -1448,6 +1448,20 @@ EXPORT_SYMBOL(of_drm_get_bridge); * * @np: device node * + * This function is deprecated. Convert to of_drm_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_get_bridge(), which is the only safe thing + * to do + * * RETURNS: * drm_bridge control struct on success, NULL on failure */ -- 2.51.1
