path: root/ipc/mqueue.c (plain)
blob: 02fb438fd3afb07f1205d2edec84e6ceab157113

1	/*
2	* POSIX message queues filesystem for Linux.
3	*
4	* Copyright (C) 2003,2004 Krzysztof Benedyczak (golbi@mat.uni.torun.pl)
5	* Michal Wronski (michal.wronski@gmail.com)
6	*
7	* Spinlocks: Mohamed Abbas (abbas.mohamed@intel.com)
8	* Lockless receive & send, fd based notify:
9	* Manfred Spraul (manfred@colorfullife.com)
10	*
11	* Audit: George Wilson (ltcgcw@us.ibm.com)
12	*
13	* This file is released under the GPL.
14	*/
15
16	#include <linux/capability.h>
17	#include <linux/init.h>
18	#include <linux/pagemap.h>
19	#include <linux/file.h>
20	#include <linux/mount.h>
21	#include <linux/namei.h>
22	#include <linux/sysctl.h>
23	#include <linux/poll.h>
24	#include <linux/mqueue.h>
25	#include <linux/msg.h>
26	#include <linux/skbuff.h>
27	#include <linux/vmalloc.h>
28	#include <linux/netlink.h>
29	#include <linux/syscalls.h>
30	#include <linux/audit.h>
31	#include <linux/signal.h>
32	#include <linux/mutex.h>
33	#include <linux/nsproxy.h>
34	#include <linux/pid.h>
35	#include <linux/ipc_namespace.h>
36	#include <linux/user_namespace.h>
37	#include <linux/slab.h>
38
39	#include <net/sock.h>
40	#include "util.h"
41
42	#define MQUEUE_MAGIC 0x19800202
43	#define DIRENT_SIZE 20
44	#define FILENT_SIZE 80
45
46	#define SEND 0
47	#define RECV 1
48
49	#define STATE_NONE 0
50	#define STATE_READY 1
51
52	struct posix_msg_tree_node {
53	struct rb_node rb_node;
54	struct list_head msg_list;
55	int priority;
56	};
57
58	struct ext_wait_queue { /* queue of sleeping tasks */
59	struct task_struct *task;
60	struct list_head list;
61	struct msg_msg *msg; /* ptr of loaded message */
62	int state; /* one of STATE_* values */
63	};
64
65	struct mqueue_inode_info {
66	spinlock_t lock;
67	struct inode vfs_inode;
68	wait_queue_head_t wait_q;
69
70	struct rb_root msg_tree;
71	struct posix_msg_tree_node *node_cache;
72	struct mq_attr attr;
73
74	struct sigevent notify;
75	struct pid *notify_owner;
76	struct user_namespace *notify_user_ns;
77	struct user_struct *user; /* user who created, for accounting */
78	struct sock *notify_sock;
79	struct sk_buff *notify_cookie;
80
81	/* for tasks waiting for free space and messages, respectively */
82	struct ext_wait_queue e_wait_q[2];
83
84	unsigned long qsize; /* size of queue in memory (sum of all msgs) */
85	};
86
87	static const struct inode_operations mqueue_dir_inode_operations;
88	static const struct file_operations mqueue_file_operations;
89	static const struct super_operations mqueue_super_ops;
90	static void remove_notification(struct mqueue_inode_info *info);
91
92	static struct kmem_cache *mqueue_inode_cachep;
93
94	static struct ctl_table_header *mq_sysctl_table;
95
96	static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
97	{
98	return container_of(inode, struct mqueue_inode_info, vfs_inode);
99	}
100
101	/*
102	* This routine should be called with the mq_lock held.
103	*/
104	static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
105	{
106	return get_ipc_ns(inode->i_sb->s_fs_info);
107	}
108
109	static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
110	{
111	struct ipc_namespace *ns;
112
113	spin_lock(&mq_lock);
114	ns = __get_ns_from_inode(inode);
115	spin_unlock(&mq_lock);
116	return ns;
117	}
118
119	/* Auxiliary functions to manipulate messages' list */
120	static int msg_insert(struct msg_msg *msg, struct mqueue_inode_info *info)
121	{
122	struct rb_node **p, *parent = NULL;
123	struct posix_msg_tree_node *leaf;
124
125	p = &info->msg_tree.rb_node;
126	while (*p) {
127	parent = *p;
128	leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
129
130	if (likely(leaf->priority == msg->m_type))
131	goto insert_msg;
132	else if (msg->m_type < leaf->priority)
133	p = &(*p)->rb_left;
134	else
135	p = &(*p)->rb_right;
136	}
137	if (info->node_cache) {
138	leaf = info->node_cache;
139	info->node_cache = NULL;
140	} else {
141	leaf = kmalloc(sizeof(*leaf), GFP_ATOMIC);
142	if (!leaf)
143	return -ENOMEM;
144	INIT_LIST_HEAD(&leaf->msg_list);
145	}
146	leaf->priority = msg->m_type;
147	rb_link_node(&leaf->rb_node, parent, p);
148	rb_insert_color(&leaf->rb_node, &info->msg_tree);
149	insert_msg:
150	info->attr.mq_curmsgs++;
151	info->qsize += msg->m_ts;
152	list_add_tail(&msg->m_list, &leaf->msg_list);
153	return 0;
154	}
155
156	static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
157	{
158	struct rb_node **p, *parent = NULL;
159	struct posix_msg_tree_node *leaf;
160	struct msg_msg *msg;
161
162	try_again:
163	p = &info->msg_tree.rb_node;
164	while (*p) {
165	parent = *p;
166	/*
167	* During insert, low priorities go to the left and high to the
168	* right. On receive, we want the highest priorities first, so
169	* walk all the way to the right.
170	*/
171	p = &(*p)->rb_right;
172	}
173	if (!parent) {
174	if (info->attr.mq_curmsgs) {
175	pr_warn_once("Inconsistency in POSIX message queue, "
176	"no tree element, but supposedly messages "
177	"should exist!\n");
178	info->attr.mq_curmsgs = 0;
179	}
180	return NULL;
181	}
182	leaf = rb_entry(parent, struct posix_msg_tree_node, rb_node);
183	if (unlikely(list_empty(&leaf->msg_list))) {
184	pr_warn_once("Inconsistency in POSIX message queue, "
185	"empty leaf node but we haven't implemented "
186	"lazy leaf delete!\n");
187	rb_erase(&leaf->rb_node, &info->msg_tree);
188	if (info->node_cache) {
189	kfree(leaf);
190	} else {
191	info->node_cache = leaf;
192	}
193	goto try_again;
194	} else {
195	msg = list_first_entry(&leaf->msg_list,
196	struct msg_msg, m_list);
197	list_del(&msg->m_list);
198	if (list_empty(&leaf->msg_list)) {
199	rb_erase(&leaf->rb_node, &info->msg_tree);
200	if (info->node_cache) {
201	kfree(leaf);
202	} else {
203	info->node_cache = leaf;
204	}
205	}
206	}
207	info->attr.mq_curmsgs--;
208	info->qsize -= msg->m_ts;
209	return msg;
210	}
211
212	static struct inode *mqueue_get_inode(struct super_block *sb,
213	struct ipc_namespace *ipc_ns, umode_t mode,
214	struct mq_attr *attr)
215	{
216	struct user_struct *u = current_user();
217	struct inode *inode;
218	int ret = -ENOMEM;
219
220	inode = new_inode(sb);
221	if (!inode)
222	goto err;
223
224	inode->i_ino = get_next_ino();
225	inode->i_mode = mode;
226	inode->i_uid = current_fsuid();
227	inode->i_gid = current_fsgid();
228	inode->i_mtime = inode->i_ctime = inode->i_atime = current_time(inode);
229
230	if (S_ISREG(mode)) {
231	struct mqueue_inode_info *info;
232	unsigned long mq_bytes, mq_treesize;
233
234	inode->i_fop = &mqueue_file_operations;
235	inode->i_size = FILENT_SIZE;
236	/* mqueue specific info */
237	info = MQUEUE_I(inode);
238	spin_lock_init(&info->lock);
239	init_waitqueue_head(&info->wait_q);
240	INIT_LIST_HEAD(&info->e_wait_q[0].list);
241	INIT_LIST_HEAD(&info->e_wait_q[1].list);
242	info->notify_owner = NULL;
243	info->notify_user_ns = NULL;
244	info->qsize = 0;
245	info->user = NULL; /* set when all is ok */
246	info->msg_tree = RB_ROOT;
247	info->node_cache = NULL;
248	memset(&info->attr, 0, sizeof(info->attr));
249	info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
250	ipc_ns->mq_msg_default);
251	info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
252	ipc_ns->mq_msgsize_default);
253	if (attr) {
254	info->attr.mq_maxmsg = attr->mq_maxmsg;
255	info->attr.mq_msgsize = attr->mq_msgsize;
256	}
257	/*
258	* We used to allocate a static array of pointers and account
259	* the size of that array as well as one msg_msg struct per
260	* possible message into the queue size. That's no longer
261	* accurate as the queue is now an rbtree and will grow and
262	* shrink depending on usage patterns. We can, however, still
263	* account one msg_msg struct per message, but the nodes are
264	* allocated depending on priority usage, and most programs
265	* only use one, or a handful, of priorities. However, since
266	* this is pinned memory, we need to assume worst case, so
267	* that means the min(mq_maxmsg, max_priorities) * struct
268	* posix_msg_tree_node.
269	*/
270	mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
271	min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
272	sizeof(struct posix_msg_tree_node);
273
274	mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
275	info->attr.mq_msgsize);
276
277	spin_lock(&mq_lock);
278	if (u->mq_bytes + mq_bytes < u->mq_bytes ||
279	u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
280	spin_unlock(&mq_lock);
281	/* mqueue_evict_inode() releases info->messages */
282	ret = -EMFILE;
283	goto out_inode;
284	}
285	u->mq_bytes += mq_bytes;
286	spin_unlock(&mq_lock);
287
288	/* all is ok */
289	info->user = get_uid(u);
290	} else if (S_ISDIR(mode)) {
291	inc_nlink(inode);
292	/* Some things misbehave if size == 0 on a directory */
293	inode->i_size = 2 * DIRENT_SIZE;
294	inode->i_op = &mqueue_dir_inode_operations;
295	inode->i_fop = &simple_dir_operations;
296	}
297
298	return inode;
299	out_inode:
300	iput(inode);
301	err:
302	return ERR_PTR(ret);
303	}
304
305	static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
306	{
307	struct inode *inode;
308	struct ipc_namespace *ns = sb->s_fs_info;
309
310	sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;
311	sb->s_blocksize = PAGE_SIZE;
312	sb->s_blocksize_bits = PAGE_SHIFT;
313	sb->s_magic = MQUEUE_MAGIC;
314	sb->s_op = &mqueue_super_ops;
315
316	inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
317	if (IS_ERR(inode))
318	return PTR_ERR(inode);
319
320	sb->s_root = d_make_root(inode);
321	if (!sb->s_root)
322	return -ENOMEM;
323	return 0;
324	}
325
326	static struct dentry *mqueue_mount(struct file_system_type *fs_type,
327	int flags, const char *dev_name,
328	void *data)
329	{
330	struct ipc_namespace *ns;
331	if (flags & MS_KERNMOUNT) {
332	ns = data;
333	data = NULL;
334	} else {
335	ns = current->nsproxy->ipc_ns;
336	}
337	return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super);
338	}
339
340	static void init_once(void *foo)
341	{
342	struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
343
344	inode_init_once(&p->vfs_inode);
345	}
346
347	static struct inode *mqueue_alloc_inode(struct super_block *sb)
348	{
349	struct mqueue_inode_info *ei;
350
351	ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
352	if (!ei)
353	return NULL;
354	return &ei->vfs_inode;
355	}
356
357	static void mqueue_i_callback(struct rcu_head *head)
358	{
359	struct inode *inode = container_of(head, struct inode, i_rcu);
360	kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
361	}
362
363	static void mqueue_destroy_inode(struct inode *inode)
364	{
365	call_rcu(&inode->i_rcu, mqueue_i_callback);
366	}
367
368	static void mqueue_evict_inode(struct inode *inode)
369	{
370	struct mqueue_inode_info *info;
371	struct user_struct *user;
372	unsigned long mq_bytes, mq_treesize;
373	struct ipc_namespace *ipc_ns;
374	struct msg_msg *msg;
375
376	clear_inode(inode);
377
378	if (S_ISDIR(inode->i_mode))
379	return;
380
381	ipc_ns = get_ns_from_inode(inode);
382	info = MQUEUE_I(inode);
383	spin_lock(&info->lock);
384	while ((msg = msg_get(info)) != NULL)
385	free_msg(msg);
386	kfree(info->node_cache);
387	spin_unlock(&info->lock);
388
389	/* Total amount of bytes accounted for the mqueue */
390	mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +
391	min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *
392	sizeof(struct posix_msg_tree_node);
393
394	mq_bytes = mq_treesize + (info->attr.mq_maxmsg *
395	info->attr.mq_msgsize);
396
397	user = info->user;
398	if (user) {
399	spin_lock(&mq_lock);
400	user->mq_bytes -= mq_bytes;
401	/*
402	* get_ns_from_inode() ensures that the
403	* (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
404	* to which we now hold a reference, or it is NULL.
405	* We can't put it here under mq_lock, though.
406	*/
407	if (ipc_ns)
408	ipc_ns->mq_queues_count--;
409	spin_unlock(&mq_lock);
410	free_uid(user);
411	}
412	if (ipc_ns)
413	put_ipc_ns(ipc_ns);
414	}
415
416	static int mqueue_create(struct inode *dir, struct dentry *dentry,
417	umode_t mode, bool excl)
418	{
419	struct inode *inode;
420	struct mq_attr *attr = dentry->d_fsdata;
421	int error;
422	struct ipc_namespace *ipc_ns;
423
424	spin_lock(&mq_lock);
425	ipc_ns = __get_ns_from_inode(dir);
426	if (!ipc_ns) {
427	error = -EACCES;
428	goto out_unlock;
429	}
430
431	if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
432	!capable(CAP_SYS_RESOURCE)) {
433	error = -ENOSPC;
434	goto out_unlock;
435	}
436	ipc_ns->mq_queues_count++;
437	spin_unlock(&mq_lock);
438
439	inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
440	if (IS_ERR(inode)) {
441	error = PTR_ERR(inode);
442	spin_lock(&mq_lock);
443	ipc_ns->mq_queues_count--;
444	goto out_unlock;
445	}
446
447	put_ipc_ns(ipc_ns);
448	dir->i_size += DIRENT_SIZE;
449	dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
450
451	d_instantiate(dentry, inode);
452	dget(dentry);
453	return 0;
454	out_unlock:
455	spin_unlock(&mq_lock);
456	if (ipc_ns)
457	put_ipc_ns(ipc_ns);
458	return error;
459	}
460
461	static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
462	{
463	struct inode *inode = d_inode(dentry);
464
465	dir->i_ctime = dir->i_mtime = dir->i_atime = current_time(dir);
466	dir->i_size -= DIRENT_SIZE;
467	drop_nlink(inode);
468	dput(dentry);
469	return 0;
470	}
471
472	/*
473	* This is routine for system read from queue file.
474	* To avoid mess with doing here some sort of mq_receive we allow
475	* to read only queue size & notification info (the only values
476	* that are interesting from user point of view and aren't accessible
477	* through std routines)
478	*/
479	static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
480	size_t count, loff_t *off)
481	{
482	struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
483	char buffer[FILENT_SIZE];
484	ssize_t ret;
485
486	spin_lock(&info->lock);
487	snprintf(buffer, sizeof(buffer),
488	"QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
489	info->qsize,
490	info->notify_owner ? info->notify.sigev_notify : 0,
491	(info->notify_owner &&
492	info->notify.sigev_notify == SIGEV_SIGNAL) ?
493	info->notify.sigev_signo : 0,
494	pid_vnr(info->notify_owner));
495	spin_unlock(&info->lock);
496	buffer[sizeof(buffer)-1] = '\0';
497
498	ret = simple_read_from_buffer(u_data, count, off, buffer,
499	strlen(buffer));
500	if (ret <= 0)
501	return ret;
502
503	file_inode(filp)->i_atime = file_inode(filp)->i_ctime = current_time(file_inode(filp));
504	return ret;
505	}
506
507	static int mqueue_flush_file(struct file *filp, fl_owner_t id)
508	{
509	struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
510
511	spin_lock(&info->lock);
512	if (task_tgid(current) == info->notify_owner)
513	remove_notification(info);
514
515	spin_unlock(&info->lock);
516	return 0;
517	}
518
519	static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
520	{
521	struct mqueue_inode_info *info = MQUEUE_I(file_inode(filp));
522	int retval = 0;
523
524	poll_wait(filp, &info->wait_q, poll_tab);
525
526	spin_lock(&info->lock);
527	if (info->attr.mq_curmsgs)
528	retval = POLLIN | POLLRDNORM;
529
530	if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
531	retval |= POLLOUT | POLLWRNORM;
532	spin_unlock(&info->lock);
533
534	return retval;
535	}
536
537	/* Adds current to info->e_wait_q[sr] before element with smaller prio */
538	static void wq_add(struct mqueue_inode_info *info, int sr,
539	struct ext_wait_queue *ewp)
540	{
541	struct ext_wait_queue *walk;
542
543	ewp->task = current;
544
545	list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
546	if (walk->task->static_prio <= current->static_prio) {
547	list_add_tail(&ewp->list, &walk->list);
548	return;
549	}
550	}
551	list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
552	}
553
554	/*
555	* Puts current task to sleep. Caller must hold queue lock. After return
556	* lock isn't held.
557	* sr: SEND or RECV
558	*/
559	static int wq_sleep(struct mqueue_inode_info *info, int sr,
560	ktime_t *timeout, struct ext_wait_queue *ewp)
561	{
562	int retval;
563	signed long time;
564
565	wq_add(info, sr, ewp);
566
567	for (;;) {
568	__set_current_state(TASK_INTERRUPTIBLE);
569
570	spin_unlock(&info->lock);
571	time = schedule_hrtimeout_range_clock(timeout, 0,
572	HRTIMER_MODE_ABS, CLOCK_REALTIME);
573
574	if (ewp->state == STATE_READY) {
575	retval = 0;
576	goto out;
577	}
578	spin_lock(&info->lock);
579	if (ewp->state == STATE_READY) {
580	retval = 0;
581	goto out_unlock;
582	}
583	if (signal_pending(current)) {
584	retval = -ERESTARTSYS;
585	break;
586	}
587	if (time == 0) {
588	retval = -ETIMEDOUT;
589	break;
590	}
591	}
592	list_del(&ewp->list);
593	out_unlock:
594	spin_unlock(&info->lock);
595	out:
596	return retval;
597	}
598
599	/*
600	* Returns waiting task that should be serviced first or NULL if none exists
601	*/
602	static struct ext_wait_queue *wq_get_first_waiter(
603	struct mqueue_inode_info *info, int sr)
604	{
605	struct list_head *ptr;
606
607	ptr = info->e_wait_q[sr].list.prev;
608	if (ptr == &info->e_wait_q[sr].list)
609	return NULL;
610	return list_entry(ptr, struct ext_wait_queue, list);
611	}
612
613
614	static inline void set_cookie(struct sk_buff *skb, char code)
615	{
616	((char *)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
617	}
618
619	/*
620	* The next function is only to split too long sys_mq_timedsend
621	*/
622	static void __do_notify(struct mqueue_inode_info *info)
623	{
624	/* notification
625	* invoked when there is registered process and there isn't process
626	* waiting synchronously for message AND state of queue changed from
627	* empty to not empty. Here we are sure that no one is waiting
628	* synchronously. */
629	if (info->notify_owner &&
630	info->attr.mq_curmsgs == 1) {
631	struct siginfo sig_i;
632	switch (info->notify.sigev_notify) {
633	case SIGEV_NONE:
634	break;
635	case SIGEV_SIGNAL:
636	/* sends signal */
637
638	sig_i.si_signo = info->notify.sigev_signo;
639	sig_i.si_errno = 0;
640	sig_i.si_code = SI_MESGQ;
641	sig_i.si_value = info->notify.sigev_value;
642	/* map current pid/uid into info->owner's namespaces */
643	rcu_read_lock();
644	sig_i.si_pid = task_tgid_nr_ns(current,
645	ns_of_pid(info->notify_owner));
646	sig_i.si_uid = from_kuid_munged(info->notify_user_ns, current_uid());
647	rcu_read_unlock();
648
649	kill_pid_info(info->notify.sigev_signo,
650	&sig_i, info->notify_owner);
651	break;
652	case SIGEV_THREAD:
653	set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
654	netlink_sendskb(info->notify_sock, info->notify_cookie);
655	break;
656	}
657	/* after notification unregisters process */
658	put_pid(info->notify_owner);
659	put_user_ns(info->notify_user_ns);
660	info->notify_owner = NULL;
661	info->notify_user_ns = NULL;
662	}
663	wake_up(&info->wait_q);
664	}
665
666	static int prepare_timeout(const struct timespec __user *u_abs_timeout,
667	ktime_t *expires, struct timespec *ts)
668	{
669	if (copy_from_user(ts, u_abs_timeout, sizeof(struct timespec)))
670	return -EFAULT;
671	if (!timespec_valid(ts))
672	return -EINVAL;
673
674	*expires = timespec_to_ktime(*ts);
675	return 0;
676	}
677
678	static void remove_notification(struct mqueue_inode_info *info)
679	{
680	if (info->notify_owner != NULL &&
681	info->notify.sigev_notify == SIGEV_THREAD) {
682	set_cookie(info->notify_cookie, NOTIFY_REMOVED);
683	netlink_sendskb(info->notify_sock, info->notify_cookie);
684	}
685	put_pid(info->notify_owner);
686	put_user_ns(info->notify_user_ns);
687	info->notify_owner = NULL;
688	info->notify_user_ns = NULL;
689	}
690
691	static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
692	{
693	int mq_treesize;
694	unsigned long total_size;
695
696	if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
697	return -EINVAL;
698	if (capable(CAP_SYS_RESOURCE)) {
699	if (attr->mq_maxmsg > HARD_MSGMAX ||
700	attr->mq_msgsize > HARD_MSGSIZEMAX)
701	return -EINVAL;
702	} else {
703	if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
704	attr->mq_msgsize > ipc_ns->mq_msgsize_max)
705	return -EINVAL;
706	}
707	/* check for overflow */
708	if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
709	return -EOVERFLOW;
710	mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +
711	min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *
712	sizeof(struct posix_msg_tree_node);
713	total_size = attr->mq_maxmsg * attr->mq_msgsize;
714	if (total_size + mq_treesize < total_size)
715	return -EOVERFLOW;
716	return 0;
717	}
718
719	/*
720	* Invoked when creating a new queue via sys_mq_open
721	*/
722	static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,
723	struct path *path, int oflag, umode_t mode,
724	struct mq_attr *attr)
725	{
726	const struct cred *cred = current_cred();
727	int ret;
728
729	if (attr) {
730	ret = mq_attr_ok(ipc_ns, attr);
731	if (ret)
732	return ERR_PTR(ret);
733	/* store for use during create */
734	path->dentry->d_fsdata = attr;
735	} else {
736	struct mq_attr def_attr;
737
738	def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,
739	ipc_ns->mq_msg_default);
740	def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,
741	ipc_ns->mq_msgsize_default);
742	ret = mq_attr_ok(ipc_ns, &def_attr);
743	if (ret)
744	return ERR_PTR(ret);
745	}
746
747	mode &= ~current_umask();
748	ret = vfs_create2(path->mnt, dir, path->dentry, mode, true);
749	path->dentry->d_fsdata = NULL;
750	if (ret)
751	return ERR_PTR(ret);
752	return dentry_open(path, oflag, cred);
753	}
754
755	/* Opens existing queue */
756	static struct file *do_open(struct path *path, int oflag)
757	{
758	static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
759	MAY_READ | MAY_WRITE };
760	int acc;
761	if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))
762	return ERR_PTR(-EINVAL);
763	acc = oflag2acc[oflag & O_ACCMODE];
764	if (inode_permission2(path->mnt, d_inode(path->dentry), acc))
765	return ERR_PTR(-EACCES);
766	return dentry_open(path, oflag, current_cred());
767	}
768
769	SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, umode_t, mode,
770	struct mq_attr __user *, u_attr)
771	{
772	struct path path;
773	struct file *filp;
774	struct filename *name;
775	struct mq_attr attr;
776	int fd, error;
777	struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
778	struct vfsmount *mnt = ipc_ns->mq_mnt;
779	struct dentry *root = mnt->mnt_root;
780	int ro;
781
782	if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
783	return -EFAULT;
784
785	audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
786
787	if (IS_ERR(name = getname(u_name)))
788	return PTR_ERR(name);
789
790	fd = get_unused_fd_flags(O_CLOEXEC);
791	if (fd < 0)
792	goto out_putname;
793
794	ro = mnt_want_write(mnt); /* we'll drop it in any case */
795	error = 0;
796	inode_lock(d_inode(root));
797	path.dentry = lookup_one_len2(name->name, mnt, root, strlen(name->name));
798	if (IS_ERR(path.dentry)) {
799	error = PTR_ERR(path.dentry);
800	goto out_putfd;
801	}
802	path.mnt = mntget(mnt);
803
804	if (oflag & O_CREAT) {
805	if (d_really_is_positive(path.dentry)) { /* entry already exists */
806	audit_inode(name, path.dentry, 0);
807	if (oflag & O_EXCL) {
808	error = -EEXIST;
809	goto out;
810	}
811	filp = do_open(&path, oflag);
812	} else {
813	if (ro) {
814	error = ro;
815	goto out;
816	}
817	audit_inode_parent_hidden(name, root);
818	filp = do_create(ipc_ns, d_inode(root),
819	&path, oflag, mode,
820	u_attr ? &attr : NULL);
821	}
822	} else {
823	if (d_really_is_negative(path.dentry)) {
824	error = -ENOENT;
825	goto out;
826	}
827	audit_inode(name, path.dentry, 0);
828	filp = do_open(&path, oflag);
829	}
830
831	if (!IS_ERR(filp))
832	fd_install(fd, filp);
833	else
834	error = PTR_ERR(filp);
835	out:
836	path_put(&path);
837	out_putfd:
838	if (error) {
839	put_unused_fd(fd);
840	fd = error;
841	}
842	inode_unlock(d_inode(root));
843	if (!ro)
844	mnt_drop_write(mnt);
845	out_putname:
846	putname(name);
847	return fd;
848	}
849
850	SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
851	{
852	int err;
853	struct filename *name;
854	struct dentry *dentry;
855	struct inode *inode = NULL;
856	struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
857	struct vfsmount *mnt = ipc_ns->mq_mnt;
858
859	name = getname(u_name);
860	if (IS_ERR(name))
861	return PTR_ERR(name);
862
863	audit_inode_parent_hidden(name, mnt->mnt_root);
864	err = mnt_want_write(mnt);
865	if (err)
866	goto out_name;
867	inode_lock_nested(d_inode(mnt->mnt_root), I_MUTEX_PARENT);
868	dentry = lookup_one_len2(name->name, mnt, mnt->mnt_root,
869	strlen(name->name));
870	if (IS_ERR(dentry)) {
871	err = PTR_ERR(dentry);
872	goto out_unlock;
873	}
874
875	inode = d_inode(dentry);
876	if (!inode) {
877	err = -ENOENT;
878	} else {
879	ihold(inode);
880	err = vfs_unlink2(mnt, d_inode(dentry->d_parent), dentry, NULL);
881	}
882	dput(dentry);
883
884	out_unlock:
885	inode_unlock(d_inode(mnt->mnt_root));
886	if (inode)
887	iput(inode);
888	mnt_drop_write(mnt);
889	out_name:
890	putname(name);
891
892	return err;
893	}
894
895	/* Pipelined send and receive functions.
896	*
897	* If a receiver finds no waiting message, then it registers itself in the
898	* list of waiting receivers. A sender checks that list before adding the new
899	* message into the message array. If there is a waiting receiver, then it
900	* bypasses the message array and directly hands the message over to the
901	* receiver. The receiver accepts the message and returns without grabbing the
902	* queue spinlock:
903	*
904	* - Set pointer to message.
905	* - Queue the receiver task for later wakeup (without the info->lock).
906	* - Update its state to STATE_READY. Now the receiver can continue.
907	* - Wake up the process after the lock is dropped. Should the process wake up
908	* before this wakeup (due to a timeout or a signal) it will either see
909	* STATE_READY and continue or acquire the lock to check the state again.
910	*
911	* The same algorithm is used for senders.
912	*/
913
914	/* pipelined_send() - send a message directly to the task waiting in
915	* sys_mq_timedreceive() (without inserting message into a queue).
916	*/
917	static inline void pipelined_send(struct wake_q_head *wake_q,
918	struct mqueue_inode_info *info,
919	struct msg_msg *message,
920	struct ext_wait_queue *receiver)
921	{
922	receiver->msg = message;
923	list_del(&receiver->list);
924	wake_q_add(wake_q, receiver->task);
925	/*
926	* Rely on the implicit cmpxchg barrier from wake_q_add such
927	* that we can ensure that updating receiver->state is the last
928	* write operation: As once set, the receiver can continue,
929	* and if we don't have the reference count from the wake_q,
930	* yet, at that point we can later have a use-after-free
931	* condition and bogus wakeup.
932	*/
933	receiver->state = STATE_READY;
934	}
935
936	/* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
937	* gets its message and put to the queue (we have one free place for sure). */
938	static inline void pipelined_receive(struct wake_q_head *wake_q,
939	struct mqueue_inode_info *info)
940	{
941	struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
942
943	if (!sender) {
944	/* for poll */
945	wake_up_interruptible(&info->wait_q);
946	return;
947	}
948	if (msg_insert(sender->msg, info))
949	return;
950
951	list_del(&sender->list);
952	wake_q_add(wake_q, sender->task);
953	sender->state = STATE_READY;
954	}
955
956	SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
957	size_t, msg_len, unsigned int, msg_prio,
958	const struct timespec __user *, u_abs_timeout)
959	{
960	struct fd f;
961	struct inode *inode;
962	struct ext_wait_queue wait;
963	struct ext_wait_queue *receiver;
964	struct msg_msg *msg_ptr;
965	struct mqueue_inode_info *info;
966	ktime_t expires, *timeout = NULL;
967	struct timespec ts;
968	struct posix_msg_tree_node *new_leaf = NULL;
969	int ret = 0;
970	WAKE_Q(wake_q);
971
972	if (u_abs_timeout) {
973	int res = prepare_timeout(u_abs_timeout, &expires, &ts);
974	if (res)
975	return res;
976	timeout = &expires;
977	}
978
979	if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
980	return -EINVAL;
981
982	audit_mq_sendrecv(mqdes, msg_len, msg_prio, timeout ? &ts : NULL);
983
984	f = fdget(mqdes);
985	if (unlikely(!f.file)) {
986	ret = -EBADF;
987	goto out;
988	}
989
990	inode = file_inode(f.file);
991	if (unlikely(f.file->f_op != &mqueue_file_operations)) {
992	ret = -EBADF;
993	goto out_fput;
994	}
995	info = MQUEUE_I(inode);
996	audit_file(f.file);
997
998	if (unlikely(!(f.file->f_mode & FMODE_WRITE))) {
999	ret = -EBADF;
1000	goto out_fput;
1001	}
1002
1003	if (unlikely(msg_len > info->attr.mq_msgsize)) {
1004	ret = -EMSGSIZE;
1005	goto out_fput;
1006	}
1007
1008	/* First try to allocate memory, before doing anything with
1009	* existing queues. */
1010	msg_ptr = load_msg(u_msg_ptr, msg_len);
1011	if (IS_ERR(msg_ptr)) {
1012	ret = PTR_ERR(msg_ptr);
1013	goto out_fput;
1014	}
1015	msg_ptr->m_ts = msg_len;
1016	msg_ptr->m_type = msg_prio;
1017
1018	/*
1019	* msg_insert really wants us to have a valid, spare node struct so
1020	* it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1021	* fall back to that if necessary.
1022	*/
1023	if (!info->node_cache)
1024	new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1025
1026	spin_lock(&info->lock);
1027
1028	if (!info->node_cache && new_leaf) {
1029	/* Save our speculative allocation into the cache */
1030	INIT_LIST_HEAD(&new_leaf->msg_list);
1031	info->node_cache = new_leaf;
1032	new_leaf = NULL;
1033	} else {
1034	kfree(new_leaf);
1035	}
1036
1037	if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
1038	if (f.file->f_flags & O_NONBLOCK) {
1039	ret = -EAGAIN;
1040	} else {
1041	wait.task = current;
1042	wait.msg = (void *) msg_ptr;
1043	wait.state = STATE_NONE;
1044	ret = wq_sleep(info, SEND, timeout, &wait);
1045	/*
1046	* wq_sleep must be called with info->lock held, and
1047	* returns with the lock released
1048	*/
1049	goto out_free;
1050	}
1051	} else {
1052	receiver = wq_get_first_waiter(info, RECV);
1053	if (receiver) {
1054	pipelined_send(&wake_q, info, msg_ptr, receiver);
1055	} else {
1056	/* adds message to the queue */
1057	ret = msg_insert(msg_ptr, info);
1058	if (ret)
1059	goto out_unlock;
1060	__do_notify(info);
1061	}
1062	inode->i_atime = inode->i_mtime = inode->i_ctime =
1063	current_time(inode);
1064	}
1065	out_unlock:
1066	spin_unlock(&info->lock);
1067	wake_up_q(&wake_q);
1068	out_free:
1069	if (ret)
1070	free_msg(msg_ptr);
1071	out_fput:
1072	fdput(f);
1073	out:
1074	return ret;
1075	}
1076
1077	SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
1078	size_t, msg_len, unsigned int __user *, u_msg_prio,
1079	const struct timespec __user *, u_abs_timeout)
1080	{
1081	ssize_t ret;
1082	struct msg_msg *msg_ptr;
1083	struct fd f;
1084	struct inode *inode;
1085	struct mqueue_inode_info *info;
1086	struct ext_wait_queue wait;
1087	ktime_t expires, *timeout = NULL;
1088	struct timespec ts;
1089	struct posix_msg_tree_node *new_leaf = NULL;
1090
1091	if (u_abs_timeout) {
1092	int res = prepare_timeout(u_abs_timeout, &expires, &ts);
1093	if (res)
1094	return res;
1095	timeout = &expires;
1096	}
1097
1098	audit_mq_sendrecv(mqdes, msg_len, 0, timeout ? &ts : NULL);
1099
1100	f = fdget(mqdes);
1101	if (unlikely(!f.file)) {
1102	ret = -EBADF;
1103	goto out;
1104	}
1105
1106	inode = file_inode(f.file);
1107	if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1108	ret = -EBADF;
1109	goto out_fput;
1110	}
1111	info = MQUEUE_I(inode);
1112	audit_file(f.file);
1113
1114	if (unlikely(!(f.file->f_mode & FMODE_READ))) {
1115	ret = -EBADF;
1116	goto out_fput;
1117	}
1118
1119	/* checks if buffer is big enough */
1120	if (unlikely(msg_len < info->attr.mq_msgsize)) {
1121	ret = -EMSGSIZE;
1122	goto out_fput;
1123	}
1124
1125	/*
1126	* msg_insert really wants us to have a valid, spare node struct so
1127	* it doesn't have to kmalloc a GFP_ATOMIC allocation, but it will
1128	* fall back to that if necessary.
1129	*/
1130	if (!info->node_cache)
1131	new_leaf = kmalloc(sizeof(*new_leaf), GFP_KERNEL);
1132
1133	spin_lock(&info->lock);
1134
1135	if (!info->node_cache && new_leaf) {
1136	/* Save our speculative allocation into the cache */
1137	INIT_LIST_HEAD(&new_leaf->msg_list);
1138	info->node_cache = new_leaf;
1139	} else {
1140	kfree(new_leaf);
1141	}
1142
1143	if (info->attr.mq_curmsgs == 0) {
1144	if (f.file->f_flags & O_NONBLOCK) {
1145	spin_unlock(&info->lock);
1146	ret = -EAGAIN;
1147	} else {
1148	wait.task = current;
1149	wait.state = STATE_NONE;
1150	ret = wq_sleep(info, RECV, timeout, &wait);
1151	msg_ptr = wait.msg;
1152	}
1153	} else {
1154	WAKE_Q(wake_q);
1155
1156	msg_ptr = msg_get(info);
1157
1158	inode->i_atime = inode->i_mtime = inode->i_ctime =
1159	current_time(inode);
1160
1161	/* There is now free space in queue. */
1162	pipelined_receive(&wake_q, info);
1163	spin_unlock(&info->lock);
1164	wake_up_q(&wake_q);
1165	ret = 0;
1166	}
1167	if (ret == 0) {
1168	ret = msg_ptr->m_ts;
1169
1170	if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1171	store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1172	ret = -EFAULT;
1173	}
1174	free_msg(msg_ptr);
1175	}
1176	out_fput:
1177	fdput(f);
1178	out:
1179	return ret;
1180	}
1181
1182	/*
1183	* Notes: the case when user wants us to deregister (with NULL as pointer)
1184	* and he isn't currently owner of notification, will be silently discarded.
1185	* It isn't explicitly defined in the POSIX.
1186	*/
1187	SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1188	const struct sigevent __user *, u_notification)
1189	{
1190	int ret;
1191	struct fd f;
1192	struct sock *sock;
1193	struct inode *inode;
1194	struct sigevent notification;
1195	struct mqueue_inode_info *info;
1196	struct sk_buff *nc;
1197
1198	if (u_notification) {
1199	if (copy_from_user(&notification, u_notification,
1200	sizeof(struct sigevent)))
1201	return -EFAULT;
1202	}
1203
1204	audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1205
1206	nc = NULL;
1207	sock = NULL;
1208	if (u_notification != NULL) {
1209	if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1210	notification.sigev_notify != SIGEV_SIGNAL &&
1211	notification.sigev_notify != SIGEV_THREAD))
1212	return -EINVAL;
1213	if (notification.sigev_notify == SIGEV_SIGNAL &&
1214	!valid_signal(notification.sigev_signo)) {
1215	return -EINVAL;
1216	}
1217	if (notification.sigev_notify == SIGEV_THREAD) {
1218	long timeo;
1219
1220	/* create the notify skb */
1221	nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1222	if (!nc) {
1223	ret = -ENOMEM;
1224	goto out;
1225	}
1226	if (copy_from_user(nc->data,
1227	notification.sigev_value.sival_ptr,
1228	NOTIFY_COOKIE_LEN)) {
1229	ret = -EFAULT;
1230	goto out;
1231	}
1232
1233	/* TODO: add a header? */
1234	skb_put(nc, NOTIFY_COOKIE_LEN);
1235	/* and attach it to the socket */
1236	retry:
1237	f = fdget(notification.sigev_signo);
1238	if (!f.file) {
1239	ret = -EBADF;
1240	goto out;
1241	}
1242	sock = netlink_getsockbyfilp(f.file);
1243	fdput(f);
1244	if (IS_ERR(sock)) {
1245	ret = PTR_ERR(sock);
1246	sock = NULL;
1247	goto out;
1248	}
1249
1250	timeo = MAX_SCHEDULE_TIMEOUT;
1251	ret = netlink_attachskb(sock, nc, &timeo, NULL);
1252	if (ret == 1) {
1253	sock = NULL;
1254	goto retry;
1255	}
1256	if (ret) {
1257	sock = NULL;
1258	nc = NULL;
1259	goto out;
1260	}
1261	}
1262	}
1263
1264	f = fdget(mqdes);
1265	if (!f.file) {
1266	ret = -EBADF;
1267	goto out;
1268	}
1269
1270	inode = file_inode(f.file);
1271	if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1272	ret = -EBADF;
1273	goto out_fput;
1274	}
1275	info = MQUEUE_I(inode);
1276
1277	ret = 0;
1278	spin_lock(&info->lock);
1279	if (u_notification == NULL) {
1280	if (info->notify_owner == task_tgid(current)) {
1281	remove_notification(info);
1282	inode->i_atime = inode->i_ctime = current_time(inode);
1283	}
1284	} else if (info->notify_owner != NULL) {
1285	ret = -EBUSY;
1286	} else {
1287	switch (notification.sigev_notify) {
1288	case SIGEV_NONE:
1289	info->notify.sigev_notify = SIGEV_NONE;
1290	break;
1291	case SIGEV_THREAD:
1292	info->notify_sock = sock;
1293	info->notify_cookie = nc;
1294	sock = NULL;
1295	nc = NULL;
1296	info->notify.sigev_notify = SIGEV_THREAD;
1297	break;
1298	case SIGEV_SIGNAL:
1299	info->notify.sigev_signo = notification.sigev_signo;
1300	info->notify.sigev_value = notification.sigev_value;
1301	info->notify.sigev_notify = SIGEV_SIGNAL;
1302	break;
1303	}
1304
1305	info->notify_owner = get_pid(task_tgid(current));
1306	info->notify_user_ns = get_user_ns(current_user_ns());
1307	inode->i_atime = inode->i_ctime = current_time(inode);
1308	}
1309	spin_unlock(&info->lock);
1310	out_fput:
1311	fdput(f);
1312	out:
1313	if (sock)
1314	netlink_detachskb(sock, nc);
1315	else if (nc)
1316	dev_kfree_skb(nc);
1317
1318	return ret;
1319	}
1320
1321	SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1322	const struct mq_attr __user *, u_mqstat,
1323	struct mq_attr __user *, u_omqstat)
1324	{
1325	int ret;
1326	struct mq_attr mqstat, omqstat;
1327	struct fd f;
1328	struct inode *inode;
1329	struct mqueue_inode_info *info;
1330
1331	if (u_mqstat != NULL) {
1332	if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1333	return -EFAULT;
1334	if (mqstat.mq_flags & (~O_NONBLOCK))
1335	return -EINVAL;
1336	}
1337
1338	f = fdget(mqdes);
1339	if (!f.file) {
1340	ret = -EBADF;
1341	goto out;
1342	}
1343
1344	inode = file_inode(f.file);
1345	if (unlikely(f.file->f_op != &mqueue_file_operations)) {
1346	ret = -EBADF;
1347	goto out_fput;
1348	}
1349	info = MQUEUE_I(inode);
1350
1351	spin_lock(&info->lock);
1352
1353	omqstat = info->attr;
1354	omqstat.mq_flags = f.file->f_flags & O_NONBLOCK;
1355	if (u_mqstat) {
1356	audit_mq_getsetattr(mqdes, &mqstat);
1357	spin_lock(&f.file->f_lock);
1358	if (mqstat.mq_flags & O_NONBLOCK)
1359	f.file->f_flags |= O_NONBLOCK;
1360	else
1361	f.file->f_flags &= ~O_NONBLOCK;
1362	spin_unlock(&f.file->f_lock);
1363
1364	inode->i_atime = inode->i_ctime = current_time(inode);
1365	}
1366
1367	spin_unlock(&info->lock);
1368
1369	ret = 0;
1370	if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1371	sizeof(struct mq_attr)))
1372	ret = -EFAULT;
1373
1374	out_fput:
1375	fdput(f);
1376	out:
1377	return ret;
1378	}
1379
1380	static const struct inode_operations mqueue_dir_inode_operations = {
1381	.lookup = simple_lookup,
1382	.create = mqueue_create,
1383	.unlink = mqueue_unlink,
1384	};
1385
1386	static const struct file_operations mqueue_file_operations = {
1387	.flush = mqueue_flush_file,
1388	.poll = mqueue_poll_file,
1389	.read = mqueue_read_file,
1390	.llseek = default_llseek,
1391	};
1392
1393	static const struct super_operations mqueue_super_ops = {
1394	.alloc_inode = mqueue_alloc_inode,
1395	.destroy_inode = mqueue_destroy_inode,
1396	.evict_inode = mqueue_evict_inode,
1397	.statfs = simple_statfs,
1398	};
1399
1400	static struct file_system_type mqueue_fs_type = {
1401	.name = "mqueue",
1402	.mount = mqueue_mount,
1403	.kill_sb = kill_litter_super,
1404	.fs_flags = FS_USERNS_MOUNT,
1405	};
1406
1407	int mq_init_ns(struct ipc_namespace *ns)
1408	{
1409	ns->mq_queues_count = 0;
1410	ns->mq_queues_max = DFLT_QUEUESMAX;
1411	ns->mq_msg_max = DFLT_MSGMAX;
1412	ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
1413	ns->mq_msg_default = DFLT_MSG;
1414	ns->mq_msgsize_default = DFLT_MSGSIZE;
1415
1416	ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1417	if (IS_ERR(ns->mq_mnt)) {
1418	int err = PTR_ERR(ns->mq_mnt);
1419	ns->mq_mnt = NULL;
1420	return err;
1421	}
1422	return 0;
1423	}
1424
1425	void mq_clear_sbinfo(struct ipc_namespace *ns)
1426	{
1427	ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1428	}
1429
1430	void mq_put_mnt(struct ipc_namespace *ns)
1431	{
1432	kern_unmount(ns->mq_mnt);
1433	}
1434
1435	static int __init init_mqueue_fs(void)
1436	{
1437	int error;
1438
1439	mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1440	sizeof(struct mqueue_inode_info), 0,
1441	SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT, init_once);
1442	if (mqueue_inode_cachep == NULL)
1443	return -ENOMEM;
1444
1445	/* ignore failures - they are not fatal */
1446	mq_sysctl_table = mq_register_sysctl_table();
1447
1448	error = register_filesystem(&mqueue_fs_type);
1449	if (error)
1450	goto out_sysctl;
1451
1452	spin_lock_init(&mq_lock);
1453
1454	error = mq_init_ns(&init_ipc_ns);
1455	if (error)
1456	goto out_filesystem;
1457
1458	return 0;
1459
1460	out_filesystem:
1461	unregister_filesystem(&mqueue_fs_type);
1462	out_sysctl:
1463	if (mq_sysctl_table)
1464	unregister_sysctl_table(mq_sysctl_table);
1465	kmem_cache_destroy(mqueue_inode_cachep);
1466	return error;
1467	}
1468
1469	device_initcall(init_mqueue_fs);
1470