SAFE public projects git trees. - safe/jmp/linux-2.6/blob - ipc/mqueue.c

   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/netlink.h>
  28 #include <linux/syscalls.h>
  29 #include <linux/audit.h>
  30 #include <linux/signal.h>
  31 #include <linux/mutex.h>
  32 #include <linux/nsproxy.h>
  33 #include <linux/pid.h>
  34 #include <linux/ipc_namespace.h>
  35
  36 #include <net/sock.h>
  37 #include "util.h"
  38
  39 #define MQUEUE_MAGIC    0x19800202
  40 #define DIRENT_SIZE     20
  41 #define FILENT_SIZE     80
  42
  43 #define SEND            0
  44 #define RECV            1
  45
  46 #define STATE_NONE      0
  47 #define STATE_PENDING   1
  48 #define STATE_READY     2
  49
  50 /*
  51  * Define the ranges various user-specified maximum values can
  52  * be set to.
  53  */
  54 #define MIN_MSGMAX      1               /* min value for msg_max */
  55 #define MAX_MSGMAX      HARD_MSGMAX     /* max value for msg_max */
  56 #define MIN_MSGSIZEMAX  128             /* min value for msgsize_max */
  57 #define MAX_MSGSIZEMAX  (8192*128)      /* max value for msgsize_max */
  58
  59 struct ext_wait_queue {         /* queue of sleeping tasks */
  60         struct task_struct *task;
  61         struct list_head list;
  62         struct msg_msg *msg;    /* ptr of loaded message */
  63         int state;              /* one of STATE_* values */
  64 };
  65
  66 struct mqueue_inode_info {
  67         spinlock_t lock;
  68         struct inode vfs_inode;
  69         wait_queue_head_t wait_q;
  70
  71         struct msg_msg **messages;
  72         struct mq_attr attr;
  73
  74         struct sigevent notify;
  75         struct pid* notify_owner;
  76         struct user_struct *user;       /* user who created, for accounting */
  77         struct sock *notify_sock;
  78         struct sk_buff *notify_cookie;
  79
  80         /* for tasks waiting for free space and messages, respectively */
  81         struct ext_wait_queue e_wait_q[2];
  82
  83         unsigned long qsize; /* size of queue in memory (sum of all msgs) */
  84 };
  85
  86 static const struct inode_operations mqueue_dir_inode_operations;
  87 static const struct file_operations mqueue_file_operations;
  88 static struct super_operations mqueue_super_ops;
  89 static void remove_notification(struct mqueue_inode_info *info);
  90
  91 static struct kmem_cache *mqueue_inode_cachep;
  92
  93 static struct ctl_table_header * mq_sysctl_table;
  94
  95 static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
  96 {
  97         return container_of(inode, struct mqueue_inode_info, vfs_inode);
  98 }
  99
 100 /*
 101  * This routine should be called with the mq_lock held.
 102  */
 103 static inline struct ipc_namespace *__get_ns_from_inode(struct inode *inode)
 104 {
 105         return get_ipc_ns(inode->i_sb->s_fs_info);
 106 }
 107
 108 static struct ipc_namespace *get_ns_from_inode(struct inode *inode)
 109 {
 110         struct ipc_namespace *ns;
 111
 112         spin_lock(&mq_lock);
 113         ns = __get_ns_from_inode(inode);
 114         spin_unlock(&mq_lock);
 115         return ns;
 116 }
 117
 118 static struct inode *mqueue_get_inode(struct super_block *sb,
 119                 struct ipc_namespace *ipc_ns, int mode,
 120                 struct mq_attr *attr)
 121 {
 122         struct user_struct *u = current_user();
 123         struct inode *inode;
 124
 125         inode = new_inode(sb);
 126         if (inode) {
 127                 inode->i_mode = mode;
 128                 inode->i_uid = current_fsuid();
 129                 inode->i_gid = current_fsgid();
 130                 inode->i_mtime = inode->i_ctime = inode->i_atime =
 131                                 CURRENT_TIME;
 132
 133                 if (S_ISREG(mode)) {
 134                         struct mqueue_inode_info *info;
 135                         struct task_struct *p = current;
 136                         unsigned long mq_bytes, mq_msg_tblsz;
 137
 138                         inode->i_fop = &mqueue_file_operations;
 139                         inode->i_size = FILENT_SIZE;
 140                         /* mqueue specific info */
 141                         info = MQUEUE_I(inode);
 142                         spin_lock_init(&info->lock);
 143                         init_waitqueue_head(&info->wait_q);
 144                         INIT_LIST_HEAD(&info->e_wait_q[0].list);
 145                         INIT_LIST_HEAD(&info->e_wait_q[1].list);
 146                         info->messages = NULL;
 147                         info->notify_owner = NULL;
 148                         info->qsize = 0;
 149                         info->user = NULL;      /* set when all is ok */
 150                         memset(&info->attr, 0, sizeof(info->attr));
 151                         info->attr.mq_maxmsg = ipc_ns->mq_msg_max;
 152                         info->attr.mq_msgsize = ipc_ns->mq_msgsize_max;
 153                         if (attr) {
 154                                 info->attr.mq_maxmsg = attr->mq_maxmsg;
 155                                 info->attr.mq_msgsize = attr->mq_msgsize;
 156                         }
 157                         mq_msg_tblsz = info->attr.mq_maxmsg * sizeof(struct msg_msg *);
 158                         mq_bytes = (mq_msg_tblsz +
 159                                 (info->attr.mq_maxmsg * info->attr.mq_msgsize));
 160
 161                         spin_lock(&mq_lock);
 162                         if (u->mq_bytes + mq_bytes < u->mq_bytes ||
 163                             u->mq_bytes + mq_bytes >
 164                             p->signal->rlim[RLIMIT_MSGQUEUE].rlim_cur) {
 165                                 spin_unlock(&mq_lock);
 166                                 goto out_inode;
 167                         }
 168                         u->mq_bytes += mq_bytes;
 169                         spin_unlock(&mq_lock);
 170
 171                         info->messages = kmalloc(mq_msg_tblsz, GFP_KERNEL);
 172                         if (!info->messages) {
 173                                 spin_lock(&mq_lock);
 174                                 u->mq_bytes -= mq_bytes;
 175                                 spin_unlock(&mq_lock);
 176                                 goto out_inode;
 177                         }
 178                         /* all is ok */
 179                         info->user = get_uid(u);
 180                 } else if (S_ISDIR(mode)) {
 181                         inc_nlink(inode);
 182                         /* Some things misbehave if size == 0 on a directory */
 183                         inode->i_size = 2 * DIRENT_SIZE;
 184                         inode->i_op = &mqueue_dir_inode_operations;
 185                         inode->i_fop = &simple_dir_operations;
 186                 }
 187         }
 188         return inode;
 189 out_inode:
 190         make_bad_inode(inode);
 191         iput(inode);
 192         return NULL;
 193 }
 194
 195 static int mqueue_fill_super(struct super_block *sb, void *data, int silent)
 196 {
 197         struct inode *inode;
 198         struct ipc_namespace *ns = data;
 199         int error = 0;
 200
 201         sb->s_blocksize = PAGE_CACHE_SIZE;
 202         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 203         sb->s_magic = MQUEUE_MAGIC;
 204         sb->s_op = &mqueue_super_ops;
 205
 206         inode = mqueue_get_inode(sb, ns, S_IFDIR | S_ISVTX | S_IRWXUGO,
 207                                 NULL);
 208         if (!inode) {
 209                 error = -ENOMEM;
 210                 goto out;
 211         }
 212
 213         sb->s_root = d_alloc_root(inode);
 214         if (!sb->s_root) {
 215                 iput(inode);
 216                 error = -ENOMEM;
 217         }
 218
 219 out:
 220         return error;
 221 }
 222
 223 static int mqueue_get_sb(struct file_system_type *fs_type,
 224                          int flags, const char *dev_name,
 225                          void *data, struct vfsmount *mnt)
 226 {
 227         if (!(flags & MS_KERNMOUNT))
 228                 data = current->nsproxy->ipc_ns;
 229         return get_sb_ns(fs_type, flags, data, mqueue_fill_super, mnt);
 230 }
 231
 232 static void init_once(void *foo)
 233 {
 234         struct mqueue_inode_info *p = (struct mqueue_inode_info *) foo;
 235
 236         inode_init_once(&p->vfs_inode);
 237 }
 238
 239 static struct inode *mqueue_alloc_inode(struct super_block *sb)
 240 {
 241         struct mqueue_inode_info *ei;
 242
 243         ei = kmem_cache_alloc(mqueue_inode_cachep, GFP_KERNEL);
 244         if (!ei)
 245                 return NULL;
 246         return &ei->vfs_inode;
 247 }
 248
 249 static void mqueue_destroy_inode(struct inode *inode)
 250 {
 251         kmem_cache_free(mqueue_inode_cachep, MQUEUE_I(inode));
 252 }
 253
 254 static void mqueue_delete_inode(struct inode *inode)
 255 {
 256         struct mqueue_inode_info *info;
 257         struct user_struct *user;
 258         unsigned long mq_bytes;
 259         int i;
 260         struct ipc_namespace *ipc_ns;
 261
 262         if (S_ISDIR(inode->i_mode)) {
 263                 clear_inode(inode);
 264                 return;
 265         }
 266         ipc_ns = get_ns_from_inode(inode);
 267         info = MQUEUE_I(inode);
 268         spin_lock(&info->lock);
 269         for (i = 0; i < info->attr.mq_curmsgs; i++)
 270                 free_msg(info->messages[i]);
 271         kfree(info->messages);
 272         spin_unlock(&info->lock);
 273
 274         clear_inode(inode);
 275
 276         mq_bytes = (info->attr.mq_maxmsg * sizeof(struct msg_msg *) +
 277                    (info->attr.mq_maxmsg * info->attr.mq_msgsize));
 278         user = info->user;
 279         if (user) {
 280                 spin_lock(&mq_lock);
 281                 user->mq_bytes -= mq_bytes;
 282                 /*
 283                  * get_ns_from_inode() ensures that the
 284                  * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
 285                  * to which we now hold a reference, or it is NULL.
 286                  * We can't put it here under mq_lock, though.
 287                  */
 288                 if (ipc_ns)
 289                         ipc_ns->mq_queues_count--;
 290                 spin_unlock(&mq_lock);
 291                 free_uid(user);
 292         }
 293         if (ipc_ns)
 294                 put_ipc_ns(ipc_ns);
 295 }
 296
 297 static int mqueue_create(struct inode *dir, struct dentry *dentry,
 298                                 int mode, struct nameidata *nd)
 299 {
 300         struct inode *inode;
 301         struct mq_attr *attr = dentry->d_fsdata;
 302         int error;
 303         struct ipc_namespace *ipc_ns;
 304
 305         spin_lock(&mq_lock);
 306         ipc_ns = __get_ns_from_inode(dir);
 307         if (!ipc_ns) {
 308                 error = -EACCES;
 309                 goto out_unlock;
 310         }
 311         if (ipc_ns->mq_queues_count >= ipc_ns->mq_queues_max &&
 312                         !capable(CAP_SYS_RESOURCE)) {
 313                 error = -ENOSPC;
 314                 goto out_unlock;
 315         }
 316         ipc_ns->mq_queues_count++;
 317         spin_unlock(&mq_lock);
 318
 319         inode = mqueue_get_inode(dir->i_sb, ipc_ns, mode, attr);
 320         if (!inode) {
 321                 error = -ENOMEM;
 322                 spin_lock(&mq_lock);
 323                 ipc_ns->mq_queues_count--;
 324                 goto out_unlock;
 325         }
 326
 327         put_ipc_ns(ipc_ns);
 328         dir->i_size += DIRENT_SIZE;
 329         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
 330
 331         d_instantiate(dentry, inode);
 332         dget(dentry);
 333         return 0;
 334 out_unlock:
 335         spin_unlock(&mq_lock);
 336         if (ipc_ns)
 337                 put_ipc_ns(ipc_ns);
 338         return error;
 339 }
 340
 341 static int mqueue_unlink(struct inode *dir, struct dentry *dentry)
 342 {
 343         struct inode *inode = dentry->d_inode;
 344
 345         dir->i_ctime = dir->i_mtime = dir->i_atime = CURRENT_TIME;
 346         dir->i_size -= DIRENT_SIZE;
 347         drop_nlink(inode);
 348         dput(dentry);
 349         return 0;
 350 }
 351
 352 /*
 353 *       This is routine for system read from queue file.
 354 *       To avoid mess with doing here some sort of mq_receive we allow
 355 *       to read only queue size & notification info (the only values
 356 *       that are interesting from user point of view and aren't accessible
 357 *       through std routines)
 358 */
 359 static ssize_t mqueue_read_file(struct file *filp, char __user *u_data,
 360                                 size_t count, loff_t *off)
 361 {
 362         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 363         char buffer[FILENT_SIZE];
 364         ssize_t ret;
 365
 366         spin_lock(&info->lock);
 367         snprintf(buffer, sizeof(buffer),
 368                         "QSIZE:%-10lu NOTIFY:%-5d SIGNO:%-5d NOTIFY_PID:%-6d\n",
 369                         info->qsize,
 370                         info->notify_owner ? info->notify.sigev_notify : 0,
 371                         (info->notify_owner &&
 372                          info->notify.sigev_notify == SIGEV_SIGNAL) ?
 373                                 info->notify.sigev_signo : 0,
 374                         pid_vnr(info->notify_owner));
 375         spin_unlock(&info->lock);
 376         buffer[sizeof(buffer)-1] = '\0';
 377
 378         ret = simple_read_from_buffer(u_data, count, off, buffer,
 379                                 strlen(buffer));
 380         if (ret <= 0)
 381                 return ret;
 382
 383         filp->f_path.dentry->d_inode->i_atime = filp->f_path.dentry->d_inode->i_ctime = CURRENT_TIME;
 384         return ret;
 385 }
 386
 387 static int mqueue_flush_file(struct file *filp, fl_owner_t id)
 388 {
 389         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 390
 391         spin_lock(&info->lock);
 392         if (task_tgid(current) == info->notify_owner)
 393                 remove_notification(info);
 394
 395         spin_unlock(&info->lock);
 396         return 0;
 397 }
 398
 399 static unsigned int mqueue_poll_file(struct file *filp, struct poll_table_struct *poll_tab)
 400 {
 401         struct mqueue_inode_info *info = MQUEUE_I(filp->f_path.dentry->d_inode);
 402         int retval = 0;
 403
 404         poll_wait(filp, &info->wait_q, poll_tab);
 405
 406         spin_lock(&info->lock);
 407         if (info->attr.mq_curmsgs)
 408                 retval = POLLIN | POLLRDNORM;
 409
 410         if (info->attr.mq_curmsgs < info->attr.mq_maxmsg)
 411                 retval |= POLLOUT | POLLWRNORM;
 412         spin_unlock(&info->lock);
 413
 414         return retval;
 415 }
 416
 417 /* Adds current to info->e_wait_q[sr] before element with smaller prio */
 418 static void wq_add(struct mqueue_inode_info *info, int sr,
 419                         struct ext_wait_queue *ewp)
 420 {
 421         struct ext_wait_queue *walk;
 422
 423         ewp->task = current;
 424
 425         list_for_each_entry(walk, &info->e_wait_q[sr].list, list) {
 426                 if (walk->task->static_prio <= current->static_prio) {
 427                         list_add_tail(&ewp->list, &walk->list);
 428                         return;
 429                 }
 430         }
 431         list_add_tail(&ewp->list, &info->e_wait_q[sr].list);
 432 }
 433
 434 /*
 435  * Puts current task to sleep. Caller must hold queue lock. After return
 436  * lock isn't held.
 437  * sr: SEND or RECV
 438  */
 439 static int wq_sleep(struct mqueue_inode_info *info, int sr,
 440                         long timeout, struct ext_wait_queue *ewp)
 441 {
 442         int retval;
 443         signed long time;
 444
 445         wq_add(info, sr, ewp);
 446
 447         for (;;) {
 448                 set_current_state(TASK_INTERRUPTIBLE);
 449
 450                 spin_unlock(&info->lock);
 451                 time = schedule_timeout(timeout);
 452
 453                 while (ewp->state == STATE_PENDING)
 454                         cpu_relax();
 455
 456                 if (ewp->state == STATE_READY) {
 457                         retval = 0;
 458                         goto out;
 459                 }
 460                 spin_lock(&info->lock);
 461                 if (ewp->state == STATE_READY) {
 462                         retval = 0;
 463                         goto out_unlock;
 464                 }
 465                 if (signal_pending(current)) {
 466                         retval = -ERESTARTSYS;
 467                         break;
 468                 }
 469                 if (time == 0) {
 470                         retval = -ETIMEDOUT;
 471                         break;
 472                 }
 473         }
 474         list_del(&ewp->list);
 475 out_unlock:
 476         spin_unlock(&info->lock);
 477 out:
 478         return retval;
 479 }
 480
 481 /*
 482  * Returns waiting task that should be serviced first or NULL if none exists
 483  */
 484 static struct ext_wait_queue *wq_get_first_waiter(
 485                 struct mqueue_inode_info *info, int sr)
 486 {
 487         struct list_head *ptr;
 488
 489         ptr = info->e_wait_q[sr].list.prev;
 490         if (ptr == &info->e_wait_q[sr].list)
 491                 return NULL;
 492         return list_entry(ptr, struct ext_wait_queue, list);
 493 }
 494
 495 /* Auxiliary functions to manipulate messages' list */
 496 static void msg_insert(struct msg_msg *ptr, struct mqueue_inode_info *info)
 497 {
 498         int k;
 499
 500         k = info->attr.mq_curmsgs - 1;
 501         while (k >= 0 && info->messages[k]->m_type >= ptr->m_type) {
 502                 info->messages[k + 1] = info->messages[k];
 503                 k--;
 504         }
 505         info->attr.mq_curmsgs++;
 506         info->qsize += ptr->m_ts;
 507         info->messages[k + 1] = ptr;
 508 }
 509
 510 static inline struct msg_msg *msg_get(struct mqueue_inode_info *info)
 511 {
 512         info->qsize -= info->messages[--info->attr.mq_curmsgs]->m_ts;
 513         return info->messages[info->attr.mq_curmsgs];
 514 }
 515
 516 static inline void set_cookie(struct sk_buff *skb, char code)
 517 {
 518         ((char*)skb->data)[NOTIFY_COOKIE_LEN-1] = code;
 519 }
 520
 521 /*
 522  * The next function is only to split too long sys_mq_timedsend
 523  */
 524 static void __do_notify(struct mqueue_inode_info *info)
 525 {
 526         /* notification
 527          * invoked when there is registered process and there isn't process
 528          * waiting synchronously for message AND state of queue changed from
 529          * empty to not empty. Here we are sure that no one is waiting
 530          * synchronously. */
 531         if (info->notify_owner &&
 532             info->attr.mq_curmsgs == 1) {
 533                 struct siginfo sig_i;
 534                 switch (info->notify.sigev_notify) {
 535                 case SIGEV_NONE:
 536                         break;
 537                 case SIGEV_SIGNAL:
 538                         /* sends signal */
 539
 540                         sig_i.si_signo = info->notify.sigev_signo;
 541                         sig_i.si_errno = 0;
 542                         sig_i.si_code = SI_MESGQ;
 543                         sig_i.si_value = info->notify.sigev_value;
 544                         sig_i.si_pid = task_tgid_nr_ns(current,
 545                                                 ns_of_pid(info->notify_owner));
 546                         sig_i.si_uid = current_uid();
 547
 548                         kill_pid_info(info->notify.sigev_signo,
 549                                       &sig_i, info->notify_owner);
 550                         break;
 551                 case SIGEV_THREAD:
 552                         set_cookie(info->notify_cookie, NOTIFY_WOKENUP);
 553                         netlink_sendskb(info->notify_sock, info->notify_cookie);
 554                         break;
 555                 }
 556                 /* after notification unregisters process */
 557                 put_pid(info->notify_owner);
 558                 info->notify_owner = NULL;
 559         }
 560         wake_up(&info->wait_q);
 561 }
 562
 563 static long prepare_timeout(struct timespec *p)
 564 {
 565         struct timespec nowts;
 566         long timeout;
 567
 568         if (p) {
 569                 if (unlikely(p->tv_nsec < 0 || p->tv_sec < 0
 570                         || p->tv_nsec >= NSEC_PER_SEC))
 571                         return -EINVAL;
 572                 nowts = CURRENT_TIME;
 573                 /* first subtract as jiffies can't be too big */
 574                 p->tv_sec -= nowts.tv_sec;
 575                 if (p->tv_nsec < nowts.tv_nsec) {
 576                         p->tv_nsec += NSEC_PER_SEC;
 577                         p->tv_sec--;
 578                 }
 579                 p->tv_nsec -= nowts.tv_nsec;
 580                 if (p->tv_sec < 0)
 581                         return 0;
 582
 583                 timeout = timespec_to_jiffies(p) + 1;
 584         } else
 585                 return MAX_SCHEDULE_TIMEOUT;
 586
 587         return timeout;
 588 }
 589
 590 static void remove_notification(struct mqueue_inode_info *info)
 591 {
 592         if (info->notify_owner != NULL &&
 593             info->notify.sigev_notify == SIGEV_THREAD) {
 594                 set_cookie(info->notify_cookie, NOTIFY_REMOVED);
 595                 netlink_sendskb(info->notify_sock, info->notify_cookie);
 596         }
 597         put_pid(info->notify_owner);
 598         info->notify_owner = NULL;
 599 }
 600
 601 static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)
 602 {
 603         if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
 604                 return 0;
 605         if (capable(CAP_SYS_RESOURCE)) {
 606                 if (attr->mq_maxmsg > HARD_MSGMAX)
 607                         return 0;
 608         } else {
 609                 if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||
 610                                 attr->mq_msgsize > ipc_ns->mq_msgsize_max)
 611                         return 0;
 612         }
 613         /* check for overflow */
 614         if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)
 615                 return 0;
 616         if ((unsigned long)(attr->mq_maxmsg * attr->mq_msgsize) +
 617             (attr->mq_maxmsg * sizeof (struct msg_msg *)) <
 618             (unsigned long)(attr->mq_maxmsg * attr->mq_msgsize))
 619                 return 0;
 620         return 1;
 621 }
 622
 623 /*
 624  * Invoked when creating a new queue via sys_mq_open
 625  */
 626 static struct file *do_create(struct ipc_namespace *ipc_ns, struct dentry *dir,
 627                         struct dentry *dentry, int oflag, mode_t mode,
 628                         struct mq_attr *attr)
 629 {
 630         const struct cred *cred = current_cred();
 631         struct file *result;
 632         int ret;
 633
 634         if (attr) {
 635                 ret = -EINVAL;
 636                 if (!mq_attr_ok(ipc_ns, attr))
 637                         goto out;
 638                 /* store for use during create */
 639                 dentry->d_fsdata = attr;
 640         }
 641
 642         mode &= ~current_umask();
 643         ret = mnt_want_write(ipc_ns->mq_mnt);
 644         if (ret)
 645                 goto out;
 646         ret = vfs_create(dir->d_inode, dentry, mode, NULL);
 647         dentry->d_fsdata = NULL;
 648         if (ret)
 649                 goto out_drop_write;
 650
 651         result = dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
 652         /*
 653          * dentry_open() took a persistent mnt_want_write(),
 654          * so we can now drop this one.
 655          */
 656         mnt_drop_write(ipc_ns->mq_mnt);
 657         return result;
 658
 659 out_drop_write:
 660         mnt_drop_write(ipc_ns->mq_mnt);
 661 out:
 662         dput(dentry);
 663         mntput(ipc_ns->mq_mnt);
 664         return ERR_PTR(ret);
 665 }
 666
 667 /* Opens existing queue */
 668 static struct file *do_open(struct ipc_namespace *ipc_ns,
 669                                 struct dentry *dentry, int oflag)
 670 {
 671         const struct cred *cred = current_cred();
 672
 673         static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
 674                                                   MAY_READ | MAY_WRITE };
 675
 676         if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
 677                 dput(dentry);
 678                 mntput(ipc_ns->mq_mnt);
 679                 return ERR_PTR(-EINVAL);
 680         }
 681
 682         if (inode_permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE])) {
 683                 dput(dentry);
 684                 mntput(ipc_ns->mq_mnt);
 685                 return ERR_PTR(-EACCES);
 686         }
 687
 688         return dentry_open(dentry, ipc_ns->mq_mnt, oflag, cred);
 689 }
 690
 691 SYSCALL_DEFINE4(mq_open, const char __user *, u_name, int, oflag, mode_t, mode,
 692                 struct mq_attr __user *, u_attr)
 693 {
 694         struct dentry *dentry;
 695         struct file *filp;
 696         char *name;
 697         struct mq_attr attr;
 698         int fd, error;
 699         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
 700
 701         if (u_attr && copy_from_user(&attr, u_attr, sizeof(struct mq_attr)))
 702                 return -EFAULT;
 703
 704         audit_mq_open(oflag, mode, u_attr ? &attr : NULL);
 705
 706         if (IS_ERR(name = getname(u_name)))
 707                 return PTR_ERR(name);
 708
 709         fd = get_unused_fd_flags(O_CLOEXEC);
 710         if (fd < 0)
 711                 goto out_putname;
 712
 713         mutex_lock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
 714         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
 715         if (IS_ERR(dentry)) {
 716                 error = PTR_ERR(dentry);
 717                 goto out_err;
 718         }
 719         mntget(ipc_ns->mq_mnt);
 720
 721         if (oflag & O_CREAT) {
 722                 if (dentry->d_inode) {  /* entry already exists */
 723                         audit_inode(name, dentry);
 724                         error = -EEXIST;
 725                         if (oflag & O_EXCL)
 726                                 goto out;
 727                         filp = do_open(ipc_ns, dentry, oflag);
 728                 } else {
 729                         filp = do_create(ipc_ns, ipc_ns->mq_mnt->mnt_root,
 730                                                 dentry, oflag, mode,
 731                                                 u_attr ? &attr : NULL);
 732                 }
 733         } else {
 734                 error = -ENOENT;
 735                 if (!dentry->d_inode)
 736                         goto out;
 737                 audit_inode(name, dentry);
 738                 filp = do_open(ipc_ns, dentry, oflag);
 739         }
 740
 741         if (IS_ERR(filp)) {
 742                 error = PTR_ERR(filp);
 743                 goto out_putfd;
 744         }
 745
 746         fd_install(fd, filp);
 747         goto out_upsem;
 748
 749 out:
 750         dput(dentry);
 751         mntput(ipc_ns->mq_mnt);
 752 out_putfd:
 753         put_unused_fd(fd);
 754 out_err:
 755         fd = error;
 756 out_upsem:
 757         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
 758 out_putname:
 759         putname(name);
 760         return fd;
 761 }
 762
 763 SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name)
 764 {
 765         int err;
 766         char *name;
 767         struct dentry *dentry;
 768         struct inode *inode = NULL;
 769         struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
 770
 771         name = getname(u_name);
 772         if (IS_ERR(name))
 773                 return PTR_ERR(name);
 774
 775         mutex_lock_nested(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex,
 776                         I_MUTEX_PARENT);
 777         dentry = lookup_one_len(name, ipc_ns->mq_mnt->mnt_root, strlen(name));
 778         if (IS_ERR(dentry)) {
 779                 err = PTR_ERR(dentry);
 780                 goto out_unlock;
 781         }
 782
 783         if (!dentry->d_inode) {
 784                 err = -ENOENT;
 785                 goto out_err;
 786         }
 787
 788         inode = dentry->d_inode;
 789         if (inode)
 790                 atomic_inc(&inode->i_count);
 791         err = mnt_want_write(ipc_ns->mq_mnt);
 792         if (err)
 793                 goto out_err;
 794         err = vfs_unlink(dentry->d_parent->d_inode, dentry);
 795         mnt_drop_write(ipc_ns->mq_mnt);
 796 out_err:
 797         dput(dentry);
 798
 799 out_unlock:
 800         mutex_unlock(&ipc_ns->mq_mnt->mnt_root->d_inode->i_mutex);
 801         putname(name);
 802         if (inode)
 803                 iput(inode);
 804
 805         return err;
 806 }
 807
 808 /* Pipelined send and receive functions.
 809  *
 810  * If a receiver finds no waiting message, then it registers itself in the
 811  * list of waiting receivers. A sender checks that list before adding the new
 812  * message into the message array. If there is a waiting receiver, then it
 813  * bypasses the message array and directly hands the message over to the
 814  * receiver.
 815  * The receiver accepts the message and returns without grabbing the queue
 816  * spinlock. Therefore an intermediate STATE_PENDING state and memory barriers
 817  * are necessary. The same algorithm is used for sysv semaphores, see
 818  * ipc/sem.c for more details.
 819  *
 820  * The same algorithm is used for senders.
 821  */
 822
 823 /* pipelined_send() - send a message directly to the task waiting in
 824  * sys_mq_timedreceive() (without inserting message into a queue).
 825  */
 826 static inline void pipelined_send(struct mqueue_inode_info *info,
 827                                   struct msg_msg *message,
 828                                   struct ext_wait_queue *receiver)
 829 {
 830         receiver->msg = message;
 831         list_del(&receiver->list);
 832         receiver->state = STATE_PENDING;
 833         wake_up_process(receiver->task);
 834         smp_wmb();
 835         receiver->state = STATE_READY;
 836 }
 837
 838 /* pipelined_receive() - if there is task waiting in sys_mq_timedsend()
 839  * gets its message and put to the queue (we have one free place for sure). */
 840 static inline void pipelined_receive(struct mqueue_inode_info *info)
 841 {
 842         struct ext_wait_queue *sender = wq_get_first_waiter(info, SEND);
 843
 844         if (!sender) {
 845                 /* for poll */
 846                 wake_up_interruptible(&info->wait_q);
 847                 return;
 848         }
 849         msg_insert(sender->msg, info);
 850         list_del(&sender->list);
 851         sender->state = STATE_PENDING;
 852         wake_up_process(sender->task);
 853         smp_wmb();
 854         sender->state = STATE_READY;
 855 }
 856
 857 SYSCALL_DEFINE5(mq_timedsend, mqd_t, mqdes, const char __user *, u_msg_ptr,
 858                 size_t, msg_len, unsigned int, msg_prio,
 859                 const struct timespec __user *, u_abs_timeout)
 860 {
 861         struct file *filp;
 862         struct inode *inode;
 863         struct ext_wait_queue wait;
 864         struct ext_wait_queue *receiver;
 865         struct msg_msg *msg_ptr;
 866         struct mqueue_inode_info *info;
 867         struct timespec ts, *p = NULL;
 868         long timeout;
 869         int ret;
 870
 871         if (u_abs_timeout) {
 872                 if (copy_from_user(&ts, u_abs_timeout,
 873                                         sizeof(struct timespec)))
 874                         return -EFAULT;
 875                 p = &ts;
 876         }
 877
 878         if (unlikely(msg_prio >= (unsigned long) MQ_PRIO_MAX))
 879                 return -EINVAL;
 880
 881         audit_mq_sendrecv(mqdes, msg_len, msg_prio, p);
 882         timeout = prepare_timeout(p);
 883
 884         ret = -EBADF;
 885         filp = fget(mqdes);
 886         if (unlikely(!filp))
 887                 goto out;
 888
 889         inode = filp->f_path.dentry->d_inode;
 890         if (unlikely(filp->f_op != &mqueue_file_operations))
 891                 goto out_fput;
 892         info = MQUEUE_I(inode);
 893         audit_inode(NULL, filp->f_path.dentry);
 894
 895         if (unlikely(!(filp->f_mode & FMODE_WRITE)))
 896                 goto out_fput;
 897
 898         if (unlikely(msg_len > info->attr.mq_msgsize)) {
 899                 ret = -EMSGSIZE;
 900                 goto out_fput;
 901         }
 902
 903         /* First try to allocate memory, before doing anything with
 904          * existing queues. */
 905         msg_ptr = load_msg(u_msg_ptr, msg_len);
 906         if (IS_ERR(msg_ptr)) {
 907                 ret = PTR_ERR(msg_ptr);
 908                 goto out_fput;
 909         }
 910         msg_ptr->m_ts = msg_len;
 911         msg_ptr->m_type = msg_prio;
 912
 913         spin_lock(&info->lock);
 914
 915         if (info->attr.mq_curmsgs == info->attr.mq_maxmsg) {
 916                 if (filp->f_flags & O_NONBLOCK) {
 917                         spin_unlock(&info->lock);
 918                         ret = -EAGAIN;
 919                 } else if (unlikely(timeout < 0)) {
 920                         spin_unlock(&info->lock);
 921                         ret = timeout;
 922                 } else {
 923                         wait.task = current;
 924                         wait.msg = (void *) msg_ptr;
 925                         wait.state = STATE_NONE;
 926                         ret = wq_sleep(info, SEND, timeout, &wait);
 927                 }
 928                 if (ret < 0)
 929                         free_msg(msg_ptr);
 930         } else {
 931                 receiver = wq_get_first_waiter(info, RECV);
 932                 if (receiver) {
 933                         pipelined_send(info, msg_ptr, receiver);
 934                 } else {
 935                         /* adds message to the queue */
 936                         msg_insert(msg_ptr, info);
 937                         __do_notify(info);
 938                 }
 939                 inode->i_atime = inode->i_mtime = inode->i_ctime =
 940                                 CURRENT_TIME;
 941                 spin_unlock(&info->lock);
 942                 ret = 0;
 943         }
 944 out_fput:
 945         fput(filp);
 946 out:
 947         return ret;
 948 }
 949
 950 SYSCALL_DEFINE5(mq_timedreceive, mqd_t, mqdes, char __user *, u_msg_ptr,
 951                 size_t, msg_len, unsigned int __user *, u_msg_prio,
 952                 const struct timespec __user *, u_abs_timeout)
 953 {
 954         long timeout;
 955         ssize_t ret;
 956         struct msg_msg *msg_ptr;
 957         struct file *filp;
 958         struct inode *inode;
 959         struct mqueue_inode_info *info;
 960         struct ext_wait_queue wait;
 961         struct timespec ts, *p = NULL;
 962
 963         if (u_abs_timeout) {
 964                 if (copy_from_user(&ts, u_abs_timeout,
 965                                         sizeof(struct timespec)))
 966                         return -EFAULT;
 967                 p = &ts;
 968         }
 969
 970         audit_mq_sendrecv(mqdes, msg_len, 0, p);
 971         timeout = prepare_timeout(p);
 972
 973         ret = -EBADF;
 974         filp = fget(mqdes);
 975         if (unlikely(!filp))
 976                 goto out;
 977
 978         inode = filp->f_path.dentry->d_inode;
 979         if (unlikely(filp->f_op != &mqueue_file_operations))
 980                 goto out_fput;
 981         info = MQUEUE_I(inode);
 982         audit_inode(NULL, filp->f_path.dentry);
 983
 984         if (unlikely(!(filp->f_mode & FMODE_READ)))
 985                 goto out_fput;
 986
 987         /* checks if buffer is big enough */
 988         if (unlikely(msg_len < info->attr.mq_msgsize)) {
 989                 ret = -EMSGSIZE;
 990                 goto out_fput;
 991         }
 992
 993         spin_lock(&info->lock);
 994         if (info->attr.mq_curmsgs == 0) {
 995                 if (filp->f_flags & O_NONBLOCK) {
 996                         spin_unlock(&info->lock);
 997                         ret = -EAGAIN;
 998                         msg_ptr = NULL;
 999                 } else if (unlikely(timeout < 0)) {
1000                         spin_unlock(&info->lock);
1001                         ret = timeout;
1002                         msg_ptr = NULL;
1003                 } else {
1004                         wait.task = current;
1005                         wait.state = STATE_NONE;
1006                         ret = wq_sleep(info, RECV, timeout, &wait);
1007                         msg_ptr = wait.msg;
1008                 }
1009         } else {
1010                 msg_ptr = msg_get(info);
1011
1012                 inode->i_atime = inode->i_mtime = inode->i_ctime =
1013                                 CURRENT_TIME;
1014
1015                 /* There is now free space in queue. */
1016                 pipelined_receive(info);
1017                 spin_unlock(&info->lock);
1018                 ret = 0;
1019         }
1020         if (ret == 0) {
1021                 ret = msg_ptr->m_ts;
1022
1023                 if ((u_msg_prio && put_user(msg_ptr->m_type, u_msg_prio)) ||
1024                         store_msg(u_msg_ptr, msg_ptr, msg_ptr->m_ts)) {
1025                         ret = -EFAULT;
1026                 }
1027                 free_msg(msg_ptr);
1028         }
1029 out_fput:
1030         fput(filp);
1031 out:
1032         return ret;
1033 }
1034
1035 /*
1036  * Notes: the case when user wants us to deregister (with NULL as pointer)
1037  * and he isn't currently owner of notification, will be silently discarded.
1038  * It isn't explicitly defined in the POSIX.
1039  */
1040 SYSCALL_DEFINE2(mq_notify, mqd_t, mqdes,
1041                 const struct sigevent __user *, u_notification)
1042 {
1043         int ret;
1044         struct file *filp;
1045         struct sock *sock;
1046         struct inode *inode;
1047         struct sigevent notification;
1048         struct mqueue_inode_info *info;
1049         struct sk_buff *nc;
1050
1051         if (u_notification) {
1052                 if (copy_from_user(&notification, u_notification,
1053                                         sizeof(struct sigevent)))
1054                         return -EFAULT;
1055         }
1056
1057         audit_mq_notify(mqdes, u_notification ? &notification : NULL);
1058
1059         nc = NULL;
1060         sock = NULL;
1061         if (u_notification != NULL) {
1062                 if (unlikely(notification.sigev_notify != SIGEV_NONE &&
1063                              notification.sigev_notify != SIGEV_SIGNAL &&
1064                              notification.sigev_notify != SIGEV_THREAD))
1065                         return -EINVAL;
1066                 if (notification.sigev_notify == SIGEV_SIGNAL &&
1067                         !valid_signal(notification.sigev_signo)) {
1068                         return -EINVAL;
1069                 }
1070                 if (notification.sigev_notify == SIGEV_THREAD) {
1071                         long timeo;
1072
1073                         /* create the notify skb */
1074                         nc = alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL);
1075                         ret = -ENOMEM;
1076                         if (!nc)
1077                                 goto out;
1078                         ret = -EFAULT;
1079                         if (copy_from_user(nc->data,
1080                                         notification.sigev_value.sival_ptr,
1081                                         NOTIFY_COOKIE_LEN)) {
1082                                 goto out;
1083                         }
1084
1085                         /* TODO: add a header? */
1086                         skb_put(nc, NOTIFY_COOKIE_LEN);
1087                         /* and attach it to the socket */
1088 retry:
1089                         filp = fget(notification.sigev_signo);
1090                         ret = -EBADF;
1091                         if (!filp)
1092                                 goto out;
1093                         sock = netlink_getsockbyfilp(filp);
1094                         fput(filp);
1095                         if (IS_ERR(sock)) {
1096                                 ret = PTR_ERR(sock);
1097                                 sock = NULL;
1098                                 goto out;
1099                         }
1100
1101                         timeo = MAX_SCHEDULE_TIMEOUT;
1102                         ret = netlink_attachskb(sock, nc, &timeo, NULL);
1103                         if (ret == 1)
1104                                 goto retry;
1105                         if (ret) {
1106                                 sock = NULL;
1107                                 nc = NULL;
1108                                 goto out;
1109                         }
1110                 }
1111         }
1112
1113         ret = -EBADF;
1114         filp = fget(mqdes);
1115         if (!filp)
1116                 goto out;
1117
1118         inode = filp->f_path.dentry->d_inode;
1119         if (unlikely(filp->f_op != &mqueue_file_operations))
1120                 goto out_fput;
1121         info = MQUEUE_I(inode);
1122
1123         ret = 0;
1124         spin_lock(&info->lock);
1125         if (u_notification == NULL) {
1126                 if (info->notify_owner == task_tgid(current)) {
1127                         remove_notification(info);
1128                         inode->i_atime = inode->i_ctime = CURRENT_TIME;
1129                 }
1130         } else if (info->notify_owner != NULL) {
1131                 ret = -EBUSY;
1132         } else {
1133                 switch (notification.sigev_notify) {
1134                 case SIGEV_NONE:
1135                         info->notify.sigev_notify = SIGEV_NONE;
1136                         break;
1137                 case SIGEV_THREAD:
1138                         info->notify_sock = sock;
1139                         info->notify_cookie = nc;
1140                         sock = NULL;
1141                         nc = NULL;
1142                         info->notify.sigev_notify = SIGEV_THREAD;
1143                         break;
1144                 case SIGEV_SIGNAL:
1145                         info->notify.sigev_signo = notification.sigev_signo;
1146                         info->notify.sigev_value = notification.sigev_value;
1147                         info->notify.sigev_notify = SIGEV_SIGNAL;
1148                         break;
1149                 }
1150
1151                 info->notify_owner = get_pid(task_tgid(current));
1152                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1153         }
1154         spin_unlock(&info->lock);
1155 out_fput:
1156         fput(filp);
1157 out:
1158         if (sock) {
1159                 netlink_detachskb(sock, nc);
1160         } else if (nc) {
1161                 dev_kfree_skb(nc);
1162         }
1163         return ret;
1164 }
1165
1166 SYSCALL_DEFINE3(mq_getsetattr, mqd_t, mqdes,
1167                 const struct mq_attr __user *, u_mqstat,
1168                 struct mq_attr __user *, u_omqstat)
1169 {
1170         int ret;
1171         struct mq_attr mqstat, omqstat;
1172         struct file *filp;
1173         struct inode *inode;
1174         struct mqueue_inode_info *info;
1175
1176         if (u_mqstat != NULL) {
1177                 if (copy_from_user(&mqstat, u_mqstat, sizeof(struct mq_attr)))
1178                         return -EFAULT;
1179                 if (mqstat.mq_flags & (~O_NONBLOCK))
1180                         return -EINVAL;
1181         }
1182
1183         ret = -EBADF;
1184         filp = fget(mqdes);
1185         if (!filp)
1186                 goto out;
1187
1188         inode = filp->f_path.dentry->d_inode;
1189         if (unlikely(filp->f_op != &mqueue_file_operations))
1190                 goto out_fput;
1191         info = MQUEUE_I(inode);
1192
1193         spin_lock(&info->lock);
1194
1195         omqstat = info->attr;
1196         omqstat.mq_flags = filp->f_flags & O_NONBLOCK;
1197         if (u_mqstat) {
1198                 audit_mq_getsetattr(mqdes, &mqstat);
1199                 spin_lock(&filp->f_lock);
1200                 if (mqstat.mq_flags & O_NONBLOCK)
1201                         filp->f_flags |= O_NONBLOCK;
1202                 else
1203                         filp->f_flags &= ~O_NONBLOCK;
1204                 spin_unlock(&filp->f_lock);
1205
1206                 inode->i_atime = inode->i_ctime = CURRENT_TIME;
1207         }
1208
1209         spin_unlock(&info->lock);
1210
1211         ret = 0;
1212         if (u_omqstat != NULL && copy_to_user(u_omqstat, &omqstat,
1213                                                 sizeof(struct mq_attr)))
1214                 ret = -EFAULT;
1215
1216 out_fput:
1217         fput(filp);
1218 out:
1219         return ret;
1220 }
1221
1222 static const struct inode_operations mqueue_dir_inode_operations = {
1223         .lookup = simple_lookup,
1224         .create = mqueue_create,
1225         .unlink = mqueue_unlink,
1226 };
1227
1228 static const struct file_operations mqueue_file_operations = {
1229         .flush = mqueue_flush_file,
1230         .poll = mqueue_poll_file,
1231         .read = mqueue_read_file,
1232 };
1233
1234 static struct super_operations mqueue_super_ops = {
1235         .alloc_inode = mqueue_alloc_inode,
1236         .destroy_inode = mqueue_destroy_inode,
1237         .statfs = simple_statfs,
1238         .delete_inode = mqueue_delete_inode,
1239         .drop_inode = generic_delete_inode,
1240 };
1241
1242 static struct file_system_type mqueue_fs_type = {
1243         .name = "mqueue",
1244         .get_sb = mqueue_get_sb,
1245         .kill_sb = kill_litter_super,
1246 };
1247
1248 int mq_init_ns(struct ipc_namespace *ns)
1249 {
1250         ns->mq_queues_count  = 0;
1251         ns->mq_queues_max    = DFLT_QUEUESMAX;
1252         ns->mq_msg_max       = DFLT_MSGMAX;
1253         ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;
1254
1255         ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
1256         if (IS_ERR(ns->mq_mnt)) {
1257                 int err = PTR_ERR(ns->mq_mnt);
1258                 ns->mq_mnt = NULL;
1259                 return err;
1260         }
1261         return 0;
1262 }
1263
1264 void mq_clear_sbinfo(struct ipc_namespace *ns)
1265 {
1266         ns->mq_mnt->mnt_sb->s_fs_info = NULL;
1267 }
1268
1269 void mq_put_mnt(struct ipc_namespace *ns)
1270 {
1271         mntput(ns->mq_mnt);
1272 }
1273
1274 static int msg_max_limit_min = MIN_MSGMAX;
1275 static int msg_max_limit_max = MAX_MSGMAX;
1276
1277 static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
1278 static int msg_maxsize_limit_max = MAX_MSGSIZEMAX;
1279
1280 static ctl_table mq_sysctls[] = {
1281         {
1282                 .procname       = "queues_max",
1283                 .data           = &init_ipc_ns.mq_queues_max,
1284                 .maxlen         = sizeof(int),
1285                 .mode           = 0644,
1286                 .proc_handler   = &proc_dointvec,
1287         },
1288         {
1289                 .procname       = "msg_max",
1290                 .data           = &init_ipc_ns.mq_msg_max,
1291                 .maxlen         = sizeof(int),
1292                 .mode           = 0644,
1293                 .proc_handler   = &proc_dointvec_minmax,
1294                 .extra1         = &msg_max_limit_min,
1295                 .extra2         = &msg_max_limit_max,
1296         },
1297         {
1298                 .procname       = "msgsize_max",
1299                 .data           = &init_ipc_ns.mq_msgsize_max,
1300                 .maxlen         = sizeof(int),
1301                 .mode           = 0644,
1302                 .proc_handler   = &proc_dointvec_minmax,
1303                 .extra1         = &msg_maxsize_limit_min,
1304                 .extra2         = &msg_maxsize_limit_max,
1305         },
1306         { .ctl_name = 0 }
1307 };
1308
1309 static ctl_table mq_sysctl_dir[] = {
1310         {
1311                 .procname       = "mqueue",
1312                 .mode           = 0555,
1313                 .child          = mq_sysctls,
1314         },
1315         { .ctl_name = 0 }
1316 };
1317
1318 static ctl_table mq_sysctl_root[] = {
1319         {
1320                 .ctl_name       = CTL_FS,
1321                 .procname       = "fs",
1322                 .mode           = 0555,
1323                 .child          = mq_sysctl_dir,
1324         },
1325         { .ctl_name = 0 }
1326 };
1327
1328 static int __init init_mqueue_fs(void)
1329 {
1330         int error;
1331
1332         mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
1333                                 sizeof(struct mqueue_inode_info), 0,
1334                                 SLAB_HWCACHE_ALIGN, init_once);
1335         if (mqueue_inode_cachep == NULL)
1336                 return -ENOMEM;
1337
1338         /* ignore failues - they are not fatal */
1339         mq_sysctl_table = register_sysctl_table(mq_sysctl_root);
1340
1341         error = register_filesystem(&mqueue_fs_type);
1342         if (error)
1343                 goto out_sysctl;
1344
1345         spin_lock_init(&mq_lock);
1346
1347         init_ipc_ns.mq_mnt = kern_mount_data(&mqueue_fs_type, &init_ipc_ns);
1348         if (IS_ERR(init_ipc_ns.mq_mnt)) {
1349                 error = PTR_ERR(init_ipc_ns.mq_mnt);
1350                 goto out_filesystem;
1351         }
1352
1353         return 0;
1354
1355 out_filesystem:
1356         unregister_filesystem(&mqueue_fs_type);
1357 out_sysctl:
1358         if (mq_sysctl_table)
1359                 unregister_sysctl_table(mq_sysctl_table);
1360         kmem_cache_destroy(mqueue_inode_cachep);
1361         return error;
1362 }
1363
1364 __initcall(init_mqueue_fs);