ipc: scale msgmni to the number of ipc namespaces
[deliverable/linux.git] / ipc / namespace.c
1 /*
2 * linux/ipc/namespace.c
3 * Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc.
4 */
5
6 #include <linux/ipc.h>
7 #include <linux/msg.h>
8 #include <linux/ipc_namespace.h>
9 #include <linux/rcupdate.h>
10 #include <linux/nsproxy.h>
11 #include <linux/slab.h>
12
13 #include "util.h"
14
15 static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
16 {
17 struct ipc_namespace *ns;
18
19 ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
20 if (ns == NULL)
21 return ERR_PTR(-ENOMEM);
22
23 atomic_inc(&nr_ipc_ns);
24
25 sem_init_ns(ns);
26 msg_init_ns(ns);
27 shm_init_ns(ns);
28
29 kref_init(&ns->kref);
30 return ns;
31 }
32
33 struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
34 {
35 struct ipc_namespace *new_ns;
36
37 BUG_ON(!ns);
38 get_ipc_ns(ns);
39
40 if (!(flags & CLONE_NEWIPC))
41 return ns;
42
43 new_ns = clone_ipc_ns(ns);
44
45 put_ipc_ns(ns);
46 return new_ns;
47 }
48
49 /*
50 * free_ipcs - free all ipcs of one type
51 * @ns: the namespace to remove the ipcs from
52 * @ids: the table of ipcs to free
53 * @free: the function called to free each individual ipc
54 *
55 * Called for each kind of ipc when an ipc_namespace exits.
56 */
57 void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
58 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
59 {
60 struct kern_ipc_perm *perm;
61 int next_id;
62 int total, in_use;
63
64 down_write(&ids->rw_mutex);
65
66 in_use = ids->in_use;
67
68 for (total = 0, next_id = 0; total < in_use; next_id++) {
69 perm = idr_find(&ids->ipcs_idr, next_id);
70 if (perm == NULL)
71 continue;
72 ipc_lock_by_ptr(perm);
73 free(ns, perm);
74 total++;
75 }
76 up_write(&ids->rw_mutex);
77 }
78
79 void free_ipc_ns(struct kref *kref)
80 {
81 struct ipc_namespace *ns;
82
83 ns = container_of(kref, struct ipc_namespace, kref);
84 sem_exit_ns(ns);
85 msg_exit_ns(ns);
86 shm_exit_ns(ns);
87 kfree(ns);
88 atomic_dec(&nr_ipc_ns);
89 }
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