diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 5f265e8b4d49..034dbe7203bf 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -197,15 +197,22 @@ * driver. */ +/* Protect bridge_list and bridge_lingering_list */ static DEFINE_MUTEX(bridge_lock); static LIST_HEAD(bridge_list); +static LIST_HEAD(bridge_lingering_list); static void __drm_bridge_free(struct kref *kref) { struct drm_bridge *bridge = container_of(kref, struct drm_bridge, refcount); + mutex_lock(&bridge_lock); + list_del(&bridge->list); + mutex_unlock(&bridge_lock); + if (bridge->funcs->destroy) bridge->funcs->destroy(bridge); + kfree(bridge->container); } @@ -273,6 +280,7 @@ void *__devm_drm_bridge_alloc(struct device *dev, size_t size, size_t offset, return ERR_PTR(-ENOMEM); bridge = container + offset; + INIT_LIST_HEAD(&bridge->list); bridge->container = container; bridge->funcs = funcs; kref_init(&bridge->refcount); @@ -300,6 +308,14 @@ void drm_bridge_add(struct drm_bridge *bridge) drm_bridge_get(bridge); + /* + * If the bridge was previously added and then removed, it is now + * in bridge_lingering_list. Remove it or bridge_lingering_list will be + * corrupted when adding this bridge to bridge_list below. + */ + if (!list_empty(&bridge->list)) + list_del_init(&bridge->list); + mutex_init(&bridge->hpd_mutex); if (bridge->ops & DRM_BRIDGE_OP_HDMI) @@ -343,7 +359,7 @@ EXPORT_SYMBOL(devm_drm_bridge_add); void drm_bridge_remove(struct drm_bridge *bridge) { mutex_lock(&bridge_lock); - list_del_init(&bridge->list); + list_move_tail(&bridge->list, &bridge_lingering_list); mutex_unlock(&bridge_lock); mutex_destroy(&bridge->hpd_mutex);