static void free_ipc_ns(struct ipc_namespace *ns)
{
+ /* mq_put_mnt() waits for a grace period as kern_unmount()
+ * uses synchronize_rcu().
+ */
+ mq_put_mnt(ns);
sem_exit_ns(ns);
msg_exit_ns(ns);
shm_exit_ns(ns);
kfree(ns);
}
+static LLIST_HEAD(free_ipc_list);
+static void free_ipc(struct work_struct *unused)
+{
+ struct llist_node *node = llist_del_all(&free_ipc_list);
+ struct ipc_namespace *n, *t;
+
+ llist_for_each_entry_safe(n, t, node, mnt_llist)
+ free_ipc_ns(n);
+}
+
+/*
+ * The work queue is used to avoid the cost of synchronize_rcu in kern_unmount.
+ */
+static DECLARE_WORK(free_ipc_work, free_ipc);
+
/*
* put_ipc_ns - drop a reference to an ipc namespace.
* @ns: the namespace to put
if (refcount_dec_and_lock(&ns->count, &mq_lock)) {
mq_clear_sbinfo(ns);
spin_unlock(&mq_lock);
- mq_put_mnt(ns);
- free_ipc_ns(ns);
+
+ if (llist_add(&ns->mnt_llist, &free_ipc_list))
+ schedule_work(&free_ipc_work);
}
}