On Fri, 28 Jan 2022 05:09:53 -0800 Michel Lespinasse wrote:
> +
> +static LIST_HEAD(destroy_list);
> +static DEFINE_SPINLOCK(destroy_list_lock);
static bool destroyer_running;
> +
> +static void destroy_list_workfn(struct work_struct *work)
> +{
> + struct percpu_rw_semaphore *sem, *sem2;
> + LIST_HEAD(to_destroy);
> +
again:
> + spin_lock(&destroy_list_lock);
if (list_empty(&destroy_list)) {
destroyer_running = false;
spin_unlock(&destroy_list_lock);
return;
}
destroyer_running = true;
> + list_splice_init(&destroy_list, &to_destroy);
> + spin_unlock(&destroy_list_lock);
> +
> + if (list_empty(&to_destroy))
> + return;
> +
> + list_for_each_entry_safe(sem, sem2, &to_destroy, destroy_list_entry) {
list_del(&sem->destroy_list_entry);
> + percpu_free_rwsem(sem);
> + kfree(sem);
> + }
goto again;
> +}
> +
> +static DECLARE_WORK(destroy_list_work, destroy_list_workfn);
> +
> +void percpu_rwsem_async_destroy(struct percpu_rw_semaphore *sem)
> +{
> + spin_lock(&destroy_list_lock);
> + list_add_tail(&sem->destroy_list_entry, &destroy_list);
> + spin_unlock(&destroy_list_lock);
> + schedule_work(&destroy_list_work);
Nits
spin_lock(&destroy_list_lock);
1/ /* LIFO */
list_add(&sem->destroy_list_entry, &destroy_list);
2/ /* spawn worker if it is idle */
if (!destroyer_running)
3/ /* this is not critical work */
queue_work(system_unbound_wq, &destroy_list_work);
spin_unlock(&destroy_list_lock);
> +}
> --
> 2.20.1
