2 * linux/ipc/namespace.c
3 * Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc.
8 #include <linux/ipc_namespace.h>
9 #include <linux/rcupdate.h>
10 #include <linux/nsproxy.h>
11 #include <linux/slab.h>
15 static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
17 struct ipc_namespace *ns;
19 ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
21 return ERR_PTR(-ENOMEM);
23 atomic_inc(&nr_ipc_ns);
29 register_ipcns_notifier(ns);
35 struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
37 struct ipc_namespace *new_ns;
42 if (!(flags & CLONE_NEWIPC))
45 new_ns = clone_ipc_ns(ns);
52 * free_ipcs - free all ipcs of one type
53 * @ns: the namespace to remove the ipcs from
54 * @ids: the table of ipcs to free
55 * @free: the function called to free each individual ipc
57 * Called for each kind of ipc when an ipc_namespace exits.
59 void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
60 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
62 struct kern_ipc_perm *perm;
66 down_write(&ids->rw_mutex);
70 for (total = 0, next_id = 0; total < in_use; next_id++) {
71 perm = idr_find(&ids->ipcs_idr, next_id);
74 ipc_lock_by_ptr(perm);
78 up_write(&ids->rw_mutex);
81 void free_ipc_ns(struct kref *kref)
83 struct ipc_namespace *ns;
85 ns = container_of(kref, struct ipc_namespace, kref);
87 * Unregistering the hotplug notifier at the beginning guarantees
88 * that the ipc namespace won't be freed while we are inside the
89 * callback routine. Since the blocking_notifier_chain_XXX routines
90 * hold a rw lock on the notifier list, unregister_ipcns_notifier()
91 * won't take the rw lock before blocking_notifier_call_chain() has
92 * released the rd lock.
94 unregister_ipcns_notifier(ns);
99 atomic_dec(&nr_ipc_ns);