All of the current plane init / allocation functions behave slightly differently when it comes to argument sanitizing: - drm_universal_plane_init() implicitly panics if the drm_device pointer or the drm_plane_funcs pointer are NULL, and calls WARN_ON if there's no destroy implementation but goes on with the initialization. - drm_universal_plane_alloc() implicitly panics if the drm_device pointer is NULL, and will call WARN_ON and return an error if the drm_plane_funcs pointer is NULL. - drmm_universal_plane_alloc() implicitly panics if the drm_device pointer is NULL, and will call WARN_ON and return an error if the drm_plane_funcs pointer is NULL or if there is a destroy implementation. The current consensus is that the drm_device pointer, the drm_plane_funcs pointer, and the drm_plane pointer if relevant, should be considered pre-requisite and the function should panic if we encounter such a situation, and that returning an error in such a situation is not welcome. Let's make all functions consider those three pointers to be always set and explicitly panic if they aren't. And let's document that behaviour too. Link: https://lore.kernel.org/dri-devel/20231128-kms-hdmi-connector-state-v4-5-c7602158306e@xxxxxxxxxx/ Signed-off-by: Maxime Ripard <mripard@xxxxxxxxxx> --- drivers/gpu/drm/drm_plane.c | 15 +++++++++++---- include/drm/drm_plane.h | 6 ++++++ 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c index 9e8e4c60983d..ce0fa98a0e3f 100644 --- a/drivers/gpu/drm/drm_plane.c +++ b/drivers/gpu/drm/drm_plane.c @@ -482,6 +482,9 @@ static int __drm_universal_plane_init(struct drm_device *dev, * * Returns: * Zero on success, error code on failure. + * + * Panics: + * If @dev, @plane or @funcs are NULL. */ int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane, uint32_t possible_crtcs, @@ -494,6 +497,9 @@ int drm_universal_plane_init(struct drm_device *dev, struct drm_plane *plane, va_list ap; int ret; + BUG_ON(!dev); + BUG_ON(!plane); + BUG_ON(!funcs); WARN_ON(!funcs->destroy); va_start(ap, name); @@ -528,8 +534,9 @@ void *__drmm_universal_plane_alloc(struct drm_device *dev, size_t size, va_list ap; int ret; - if (WARN_ON(!funcs || funcs->destroy)) - return ERR_PTR(-EINVAL); + BUG_ON(!dev); + BUG_ON(!funcs); + WARN_ON(funcs->destroy); container = drmm_kzalloc(dev, size, GFP_KERNEL); if (!container) @@ -567,8 +574,8 @@ void *__drm_universal_plane_alloc(struct drm_device *dev, size_t size, va_list ap; int ret; - if (drm_WARN_ON(dev, !funcs)) - return ERR_PTR(-EINVAL); + BUG_ON(!dev); + BUG_ON(!funcs); container = kzalloc(size, GFP_KERNEL); if (!container) diff --git a/include/drm/drm_plane.h b/include/drm/drm_plane.h index c6565a6f9324..2dab1b360fa2 100644 --- a/include/drm/drm_plane.h +++ b/include/drm/drm_plane.h @@ -824,6 +824,9 @@ void *__drmm_universal_plane_alloc(struct drm_device *dev, * * Returns: * Pointer to new plane, or ERR_PTR on failure. + * + * Panics: + * If @dev or @funcs are NULL. */ #define drmm_universal_plane_alloc(dev, type, member, possible_crtcs, funcs, formats, \ format_count, format_modifiers, plane_type, name, ...) \ @@ -868,6 +871,9 @@ void *__drm_universal_plane_alloc(struct drm_device *dev, * * Returns: * Pointer to new plane, or ERR_PTR on failure. + * + * Panics: + * If @dev or @funcs are NULL. */ #define drm_universal_plane_alloc(dev, type, member, possible_crtcs, funcs, formats, \ format_count, format_modifiers, plane_type, name, ...) \ -- 2.43.0
