[PATCH v2 01/11] drm/bridge: drm_bridge_get/put(): ignore ERR_PTR

Luca Ceresoli
2026-04-28T09:16:23Z

Most functions returning a struct drm_bridge pointer currently return a
valid pointer or NULL, but this restricts their ability to return an error
code describing the error kind.

In preparation to have new APIs that can return a struct drm_bridge pointer
holding an ERR_PTR (and for those which already do) make drm_bridge_get()
and drm_bridge_put() ignore ERR_PTR values, just like they ignore NULL
pointers.

This will avoid annoying error checking in many places and the risk of
missing error checks.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/all/20260318152533.GA633439@killaraus.ideasonboard.com/
Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Link: https://lore.kernel.org/all/omlnswxukeqgnatzdvooaashgkfcacjevkvbkm6xt33itgua2k@jcmzll2w6kdq/
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

---

Patch added in v2
---
drivers/gpu/drm/drm_bridge.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 986e4c79a4e0..cea5babbe99e 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -282,7 +282,7 @@ static void __drm_bridge_free(struct kref *kref)

/**
* drm_bridge_get - Acquire a bridge reference
- * @bridge: DRM bridge; if NULL this function does nothing
+ * @bridge: DRM bridge; if NULL or an ERR_PTR this function does nothing
*
* This function increments the bridge's refcount.
*
@@ -291,7 +291,7 @@ static void __drm_bridge_free(struct kref *kref)
*/
struct drm_bridge *drm_bridge_get(struct drm_bridge *bridge)
{
- if (bridge)
+ if (!IS_ERR_OR_NULL(bridge))
kref_get(&bridge->refcount);

return bridge;
@@ -300,7 +300,7 @@ EXPORT_SYMBOL(drm_bridge_get);

/**
* drm_bridge_put - Release a bridge reference
- * @bridge: DRM bridge; if NULL this function does nothing
+ * @bridge: DRM bridge; if NULL or an ERR_PTR this function does nothing
*
* This function decrements the bridge's reference count and frees the
* object if the reference count drops to zero.
@@ -310,7 +310,7 @@ EXPORT_SYMBOL(drm_bridge_get);
*/
void drm_bridge_put(struct drm_bridge *bridge)
{
- if (bridge)
+ if (!IS_ERR_OR_NULL(bridge))
kref_put(&bridge->refcount, __drm_bridge_free);
}
EXPORT_SYMBOL(drm_bridge_put);
@@ -319,8 +319,8 @@ EXPORT_SYMBOL(drm_bridge_put);
* drm_bridge_clear_and_put - Given a bridge pointer, clear the pointer
* then put the bridge
* @bridge_pp: pointer to pointer to a struct drm_bridge; ``bridge_pp``
- * must be non-NULL; if ``*bridge_pp`` is NULL this function
- * does nothing
+ * must be non-NULL; if ``*bridge_pp`` is NULL or an ERR_PTR
+ * this function does nothing
*
* Helper to put a DRM bridge, but only after setting its pointer to
* NULL. Useful when a struct drm_bridge reference must be dropped without

--
2.53.0