diff --git a/drivers/base/core.c b/drivers/base/core.c index 96f73aaf71da3..8b3c3fcf35a96 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -83,6 +83,11 @@ int device_links_read_lock_held(void) { return srcu_read_lock_held(&device_links_srcu); } + +static void device_link_synchronize_removal(void) +{ + synchronize_srcu(&device_links_srcu); +} #else /* !CONFIG_SRCU */ static DECLARE_RWSEM(device_links_lock); @@ -113,6 +118,10 @@ int device_links_read_lock_held(void) return lockdep_is_held(&device_links_lock); } #endif + +static inline void device_link_synchronize_removal(void) +{ +} #endif /* !CONFIG_SRCU */ static bool device_is_ancestor(struct device *dev, struct device *target) @@ -332,8 +341,13 @@ static struct attribute *devlink_attrs[] = { }; ATTRIBUTE_GROUPS(devlink); -static void device_link_free(struct device_link *link) +static void device_link_release_fn(struct work_struct *work) { + struct device_link *link = container_of(work, struct device_link, rm_work); + + /* Ensure that all references to the link object have been dropped. */ + device_link_synchronize_removal(); + while (refcount_dec_not_one(&link->rpm_active)) pm_runtime_put(link->supplier); @@ -342,24 +356,19 @@ static void device_link_free(struct device_link *link) kfree(link); } -#ifdef CONFIG_SRCU -static void __device_link_free_srcu(struct rcu_head *rhead) -{ - device_link_free(container_of(rhead, struct device_link, rcu_head)); -} - static void devlink_dev_release(struct device *dev) { struct device_link *link = to_devlink(dev); - call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu); -} -#else -static void devlink_dev_release(struct device *dev) -{ - device_link_free(to_devlink(dev)); + INIT_WORK(&link->rm_work, device_link_release_fn); + /* + * It may take a while to complete this work because of the SRCU + * synchronization in device_link_release_fn() and if the consumer or + * supplier devices get deleted when it runs, so put it into the "long" + * workqueue. + */ + queue_work(system_long_wq, &link->rm_work); } -#endif static struct class devlink_class = { .name = "devlink", diff --git a/include/linux/device.h b/include/linux/device.h index 75a24b32fee8a..8d97871631d02 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -570,7 +570,7 @@ struct device { * @flags: Link flags. * @rpm_active: Whether or not the consumer device is runtime-PM-active. * @kref: Count repeated addition of the same link. - * @rcu_head: An RCU head to use for deferred execution of SRCU callbacks. + * @rm_work: Work structure used for removing the link. * @supplier_preactivated: Supplier has been made active before consumer probe. */ struct device_link { @@ -583,9 +583,7 @@ struct device_link { u32 flags; refcount_t rpm_active; struct kref kref; -#ifdef CONFIG_SRCU - struct rcu_head rcu_head; -#endif + struct work_struct rm_work; bool supplier_preactivated; /* Owned by consumer probe. */ };