net/ipv4/inet_hashtables.c

   1 /*
   2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
   3  *              operating system.  INET is implemented using the BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              Generic INET transport hashtables
   7  *
   8  * Authors:     Lotsa people, from code originally in tcp
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/random.h>
  18 #include <linux/sched.h>
  19 #include <linux/slab.h>
  20 #include <linux/wait.h>
  21 #include <linux/vmalloc.h>
  22
  23 #include <net/inet_connection_sock.h>
  24 #include <net/inet_hashtables.h>
  25 #include <net/secure_seq.h>
  26 #include <net/ip.h>
  27
  28 static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
  29                         const __u16 lport, const __be32 faddr,
  30                         const __be16 fport)
  31 {
  32         static u32 inet_ehash_secret __read_mostly;
  33
  34         net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));
  35
  36         return __inet_ehashfn(laddr, lport, faddr, fport,
  37                               inet_ehash_secret + net_hash_mix(net));
  38 }
  39
  40 /* This function handles inet_sock, but also timewait and request sockets
  41  * for IPv4/IPv6.
  42  */
  43 u32 sk_ehashfn(const struct sock *sk)
  44 {
  45 #if IS_ENABLED(CONFIG_IPV6)
  46         if (sk->sk_family == AF_INET6 &&
  47             !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
  48                 return inet6_ehashfn(sock_net(sk),
  49                                      &sk->sk_v6_rcv_saddr, sk->sk_num,
  50                                      &sk->sk_v6_daddr, sk->sk_dport);
  51 #endif
  52         return inet_ehashfn(sock_net(sk),
  53                             sk->sk_rcv_saddr, sk->sk_num,
  54                             sk->sk_daddr, sk->sk_dport);
  55 }
  56
  57 /*
  58  * Allocate and initialize a new local port bind bucket.
  59  * The bindhash mutex for snum's hash chain must be held here.
  60  */
  61 struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
  62                                                  struct net *net,
  63                                                  struct inet_bind_hashbucket *head,
  64                                                  const unsigned short snum)
  65 {
  66         struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
  67
  68         if (tb) {
  69                 write_pnet(&tb->ib_net, net);
  70                 tb->port      = snum;
  71                 tb->fastreuse = 0;
  72                 tb->fastreuseport = 0;
  73                 tb->num_owners = 0;
  74                 INIT_HLIST_HEAD(&tb->owners);
  75                 hlist_add_head(&tb->node, &head->chain);
  76         }
  77         return tb;
  78 }
  79
  80 /*
  81  * Caller must hold hashbucket lock for this tb with local BH disabled
  82  */
  83 void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
  84 {
  85         if (hlist_empty(&tb->owners)) {
  86                 __hlist_del(&tb->node);
  87                 kmem_cache_free(cachep, tb);
  88         }
  89 }
  90
  91 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
  92                     const unsigned short snum)
  93 {
  94         inet_sk(sk)->inet_num = snum;
  95         sk_add_bind_node(sk, &tb->owners);
  96         tb->num_owners++;
  97         inet_csk(sk)->icsk_bind_hash = tb;
  98 }
  99
 100 /*
 101  * Get rid of any references to a local port held by the given sock.
 102  */
 103 static void __inet_put_port(struct sock *sk)
 104 {
 105         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 106         const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
 107                         hashinfo->bhash_size);
 108         struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
 109         struct inet_bind_bucket *tb;
 110
 111         spin_lock(&head->lock);
 112         tb = inet_csk(sk)->icsk_bind_hash;
 113         __sk_del_bind_node(sk);
 114         tb->num_owners--;
 115         inet_csk(sk)->icsk_bind_hash = NULL;
 116         inet_sk(sk)->inet_num = 0;
 117         inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
 118         spin_unlock(&head->lock);
 119 }
 120
 121 void inet_put_port(struct sock *sk)
 122 {
 123         local_bh_disable();
 124         __inet_put_port(sk);
 125         local_bh_enable();
 126 }
 127 EXPORT_SYMBOL(inet_put_port);
 128
 129 int __inet_inherit_port(const struct sock *sk, struct sock *child)
 130 {
 131         struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
 132         unsigned short port = inet_sk(child)->inet_num;
 133         const int bhash = inet_bhashfn(sock_net(sk), port,
 134                         table->bhash_size);
 135         struct inet_bind_hashbucket *head = &table->bhash[bhash];
 136         struct inet_bind_bucket *tb;
 137
 138         spin_lock(&head->lock);
 139         tb = inet_csk(sk)->icsk_bind_hash;
 140         if (unlikely(!tb)) {
 141                 spin_unlock(&head->lock);
 142                 return -ENOENT;
 143         }
 144         if (tb->port != port) {
 145                 /* NOTE: using tproxy and redirecting skbs to a proxy
 146                  * on a different listener port breaks the assumption
 147                  * that the listener socket's icsk_bind_hash is the same
 148                  * as that of the child socket. We have to look up or
 149                  * create a new bind bucket for the child here. */
 150                 inet_bind_bucket_for_each(tb, &head->chain) {
 151                         if (net_eq(ib_net(tb), sock_net(sk)) &&
 152                             tb->port == port)
 153                                 break;
 154                 }
 155                 if (!tb) {
 156                         tb = inet_bind_bucket_create(table->bind_bucket_cachep,
 157                                                      sock_net(sk), head, port);
 158                         if (!tb) {
 159                                 spin_unlock(&head->lock);
 160                                 return -ENOMEM;
 161                         }
 162                 }
 163         }
 164         inet_bind_hash(child, tb, port);
 165         spin_unlock(&head->lock);
 166
 167         return 0;
 168 }
 169 EXPORT_SYMBOL_GPL(__inet_inherit_port);
 170
 171 static inline int compute_score(struct sock *sk, struct net *net,
 172                                 const unsigned short hnum, const __be32 daddr,
 173                                 const int dif)
 174 {
 175         int score = -1;
 176         struct inet_sock *inet = inet_sk(sk);
 177
 178         if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
 179                         !ipv6_only_sock(sk)) {
 180                 __be32 rcv_saddr = inet->inet_rcv_saddr;
 181                 score = sk->sk_family == PF_INET ? 2 : 1;
 182                 if (rcv_saddr) {
 183                         if (rcv_saddr != daddr)
 184                                 return -1;
 185                         score += 4;
 186                 }
 187                 if (sk->sk_bound_dev_if) {
 188                         if (sk->sk_bound_dev_if != dif)
 189                                 return -1;
 190                         score += 4;
 191                 }
 192                 if (sk->sk_incoming_cpu == raw_smp_processor_id())
 193                         score++;
 194         }
 195         return score;
 196 }
 197
 198 /*
 199  * Don't inline this cruft. Here are some nice properties to exploit here. The
 200  * BSD API does not allow a listening sock to specify the remote port nor the
 201  * remote address for the connection. So always assume those are both
 202  * wildcarded during the search since they can never be otherwise.
 203  */
 204
 205
 206 struct sock *__inet_lookup_listener(struct net *net,
 207                                     struct inet_hashinfo *hashinfo,
 208                                     const __be32 saddr, __be16 sport,
 209                                     const __be32 daddr, const unsigned short hnum,
 210                                     const int dif)
 211 {
 212         struct sock *sk, *result;
 213         struct hlist_nulls_node *node;
 214         unsigned int hash = inet_lhashfn(net, hnum);
 215         struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
 216         int score, hiscore, matches = 0, reuseport = 0;
 217         u32 phash = 0;
 218
 219         rcu_read_lock();
 220 begin:
 221         result = NULL;
 222         hiscore = 0;
 223         sk_nulls_for_each_rcu(sk, node, &ilb->head) {
 224                 score = compute_score(sk, net, hnum, daddr, dif);
 225                 if (score > hiscore) {
 226                         result = sk;
 227                         hiscore = score;
 228                         reuseport = sk->sk_reuseport;
 229                         if (reuseport) {
 230                                 phash = inet_ehashfn(net, daddr, hnum,
 231                                                      saddr, sport);
 232                                 matches = 1;
 233                         }
 234                 } else if (score == hiscore && reuseport) {
 235                         matches++;
 236                         if (reciprocal_scale(phash, matches) == 0)
 237                                 result = sk;
 238                         phash = next_pseudo_random32(phash);
 239                 }
 240         }
 241         /*
 242          * if the nulls value we got at the end of this lookup is
 243          * not the expected one, we must restart lookup.
 244          * We probably met an item that was moved to another chain.
 245          */
 246         if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
 247                 goto begin;
 248         if (result) {
 249                 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
 250                         result = NULL;
 251                 else if (unlikely(compute_score(result, net, hnum, daddr,
 252                                   dif) < hiscore)) {
 253                         sock_put(result);
 254                         goto begin;
 255                 }
 256         }
 257         rcu_read_unlock();
 258         return result;
 259 }
 260 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
 261
 262 /* All sockets share common refcount, but have different destructors */
 263 void sock_gen_put(struct sock *sk)
 264 {
 265         if (!atomic_dec_and_test(&sk->sk_refcnt))
 266                 return;
 267
 268         if (sk->sk_state == TCP_TIME_WAIT)
 269                 inet_twsk_free(inet_twsk(sk));
 270         else if (sk->sk_state == TCP_NEW_SYN_RECV)
 271                 reqsk_free(inet_reqsk(sk));
 272         else
 273                 sk_free(sk);
 274 }
 275 EXPORT_SYMBOL_GPL(sock_gen_put);
 276
 277 void sock_edemux(struct sk_buff *skb)
 278 {
 279         sock_gen_put(skb->sk);
 280 }
 281 EXPORT_SYMBOL(sock_edemux);
 282
 283 struct sock *__inet_lookup_established(struct net *net,
 284                                   struct inet_hashinfo *hashinfo,
 285                                   const __be32 saddr, const __be16 sport,
 286                                   const __be32 daddr, const u16 hnum,
 287                                   const int dif)
 288 {
 289         INET_ADDR_COOKIE(acookie, saddr, daddr);
 290         const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
 291         struct sock *sk;
 292         const struct hlist_nulls_node *node;
 293         /* Optimize here for direct hit, only listening connections can
 294          * have wildcards anyways.
 295          */
 296         unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
 297         unsigned int slot = hash & hashinfo->ehash_mask;
 298         struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
 299
 300         rcu_read_lock();
 301 begin:
 302         sk_nulls_for_each_rcu(sk, node, &head->chain) {
 303                 if (sk->sk_hash != hash)
 304                         continue;
 305                 if (likely(INET_MATCH(sk, net, acookie,
 306                                       saddr, daddr, ports, dif))) {
 307                         if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
 308                                 goto out;
 309                         if (unlikely(!INET_MATCH(sk, net, acookie,
 310                                                  saddr, daddr, ports, dif))) {
 311                                 sock_gen_put(sk);
 312                                 goto begin;
 313                         }
 314                         goto found;
 315                 }
 316         }
 317         /*
 318          * if the nulls value we got at the end of this lookup is
 319          * not the expected one, we must restart lookup.
 320          * We probably met an item that was moved to another chain.
 321          */
 322         if (get_nulls_value(node) != slot)
 323                 goto begin;
 324 out:
 325         sk = NULL;
 326 found:
 327         rcu_read_unlock();
 328         return sk;
 329 }
 330 EXPORT_SYMBOL_GPL(__inet_lookup_established);
 331
 332 /* called with local bh disabled */
 333 static int __inet_check_established(struct inet_timewait_death_row *death_row,
 334                                     struct sock *sk, __u16 lport,
 335                                     struct inet_timewait_sock **twp)
 336 {
 337         struct inet_hashinfo *hinfo = death_row->hashinfo;
 338         struct inet_sock *inet = inet_sk(sk);
 339         __be32 daddr = inet->inet_rcv_saddr;
 340         __be32 saddr = inet->inet_daddr;
 341         int dif = sk->sk_bound_dev_if;
 342         INET_ADDR_COOKIE(acookie, saddr, daddr);
 343         const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
 344         struct net *net = sock_net(sk);
 345         unsigned int hash = inet_ehashfn(net, daddr, lport,
 346                                          saddr, inet->inet_dport);
 347         struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 348         spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
 349         struct sock *sk2;
 350         const struct hlist_nulls_node *node;
 351         struct inet_timewait_sock *tw = NULL;
 352
 353         spin_lock(lock);
 354
 355         sk_nulls_for_each(sk2, node, &head->chain) {
 356                 if (sk2->sk_hash != hash)
 357                         continue;
 358
 359                 if (likely(INET_MATCH(sk2, net, acookie,
 360                                          saddr, daddr, ports, dif))) {
 361                         if (sk2->sk_state == TCP_TIME_WAIT) {
 362                                 tw = inet_twsk(sk2);
 363                                 if (twsk_unique(sk, sk2, twp))
 364                                         break;
 365                         }
 366                         goto not_unique;
 367                 }
 368         }
 369
 370         /* Must record num and sport now. Otherwise we will see
 371          * in hash table socket with a funny identity.
 372          */
 373         inet->inet_num = lport;
 374         inet->inet_sport = htons(lport);
 375         sk->sk_hash = hash;
 376         WARN_ON(!sk_unhashed(sk));
 377         __sk_nulls_add_node_rcu(sk, &head->chain);
 378         if (tw) {
 379                 sk_nulls_del_node_init_rcu((struct sock *)tw);
 380                 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
 381         }
 382         spin_unlock(lock);
 383         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 384
 385         if (twp) {
 386                 *twp = tw;
 387         } else if (tw) {
 388                 /* Silly. Should hash-dance instead... */
 389                 inet_twsk_deschedule_put(tw);
 390         }
 391         return 0;
 392
 393 not_unique:
 394         spin_unlock(lock);
 395         return -EADDRNOTAVAIL;
 396 }
 397
 398 static u32 inet_sk_port_offset(const struct sock *sk)
 399 {
 400         const struct inet_sock *inet = inet_sk(sk);
 401
 402         return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
 403                                           inet->inet_daddr,
 404                                           inet->inet_dport);
 405 }
 406
 407 /* insert a socket into ehash, and eventually remove another one
 408  * (The another one can be a SYN_RECV or TIMEWAIT
 409  */
 410 int inet_ehash_insert(struct sock *sk, struct sock *osk)
 411 {
 412         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 413         struct hlist_nulls_head *list;
 414         struct inet_ehash_bucket *head;
 415         spinlock_t *lock;
 416         int ret = 0;
 417
 418         WARN_ON_ONCE(!sk_unhashed(sk));
 419
 420         sk->sk_hash = sk_ehashfn(sk);
 421         head = inet_ehash_bucket(hashinfo, sk->sk_hash);
 422         list = &head->chain;
 423         lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 424
 425         spin_lock(lock);
 426         __sk_nulls_add_node_rcu(sk, list);
 427         if (osk) {
 428                 WARN_ON(sk->sk_hash != osk->sk_hash);
 429                 sk_nulls_del_node_init_rcu(osk);
 430         }
 431         spin_unlock(lock);
 432         return ret;
 433 }
 434
 435 void __inet_hash_nolisten(struct sock *sk, struct sock *osk)
 436 {
 437         inet_ehash_insert(sk, osk);
 438         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 439 }
 440 EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
 441
 442 void __inet_hash(struct sock *sk, struct sock *osk)
 443 {
 444         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 445         struct inet_listen_hashbucket *ilb;
 446
 447         if (sk->sk_state != TCP_LISTEN)
 448                 return __inet_hash_nolisten(sk, osk);
 449
 450         WARN_ON(!sk_unhashed(sk));
 451         ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
 452
 453         spin_lock(&ilb->lock);
 454         __sk_nulls_add_node_rcu(sk, &ilb->head);
 455         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
 456         spin_unlock(&ilb->lock);
 457 }
 458 EXPORT_SYMBOL(__inet_hash);
 459
 460 void inet_hash(struct sock *sk)
 461 {
 462         if (sk->sk_state != TCP_CLOSE) {
 463                 local_bh_disable();
 464                 __inet_hash(sk, NULL);
 465                 local_bh_enable();
 466         }
 467 }
 468 EXPORT_SYMBOL_GPL(inet_hash);
 469
 470 void inet_unhash(struct sock *sk)
 471 {
 472         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 473         spinlock_t *lock;
 474         int done;
 475
 476         if (sk_unhashed(sk))
 477                 return;
 478
 479         if (sk->sk_state == TCP_LISTEN)
 480                 lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
 481         else
 482                 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
 483
 484         spin_lock_bh(lock);
 485         done = __sk_nulls_del_node_init_rcu(sk);
 486         if (done)
 487                 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 488         spin_unlock_bh(lock);
 489 }
 490 EXPORT_SYMBOL_GPL(inet_unhash);
 491
 492 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 493                 struct sock *sk, u32 port_offset,
 494                 int (*check_established)(struct inet_timewait_death_row *,
 495                         struct sock *, __u16, struct inet_timewait_sock **))
 496 {
 497         struct inet_hashinfo *hinfo = death_row->hashinfo;
 498         const unsigned short snum = inet_sk(sk)->inet_num;
 499         struct inet_bind_hashbucket *head;
 500         struct inet_bind_bucket *tb;
 501         int ret;
 502         struct net *net = sock_net(sk);
 503
 504         if (!snum) {
 505                 int i, remaining, low, high, port;
 506                 static u32 hint;
 507                 u32 offset = hint + port_offset;
 508                 struct inet_timewait_sock *tw = NULL;
 509
 510                 inet_get_local_port_range(net, &low, &high);
 511                 remaining = (high - low) + 1;
 512
 513                 /* By starting with offset being an even number,
 514                  * we tend to leave about 50% of ports for other uses,
 515                  * like bind(0).
 516                  */
 517                 offset &= ~1;
 518
 519                 local_bh_disable();
 520                 for (i = 0; i < remaining; i++) {
 521                         port = low + (i + offset) % remaining;
 522                         if (inet_is_local_reserved_port(net, port))
 523                                 continue;
 524                         head = &hinfo->bhash[inet_bhashfn(net, port,
 525                                         hinfo->bhash_size)];
 526                         spin_lock(&head->lock);
 527
 528                         /* Does not bother with rcv_saddr checks,
 529                          * because the established check is already
 530                          * unique enough.
 531                          */
 532                         inet_bind_bucket_for_each(tb, &head->chain) {
 533                                 if (net_eq(ib_net(tb), net) &&
 534                                     tb->port == port) {
 535                                         if (tb->fastreuse >= 0 ||
 536                                             tb->fastreuseport >= 0)
 537                                                 goto next_port;
 538                                         WARN_ON(hlist_empty(&tb->owners));
 539                                         if (!check_established(death_row, sk,
 540                                                                 port, &tw))
 541                                                 goto ok;
 542                                         goto next_port;
 543                                 }
 544                         }
 545
 546                         tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
 547                                         net, head, port);
 548                         if (!tb) {
 549                                 spin_unlock(&head->lock);
 550                                 break;
 551                         }
 552                         tb->fastreuse = -1;
 553                         tb->fastreuseport = -1;
 554                         goto ok;
 555
 556                 next_port:
 557                         spin_unlock(&head->lock);
 558                 }
 559                 local_bh_enable();
 560
 561                 return -EADDRNOTAVAIL;
 562
 563 ok:
 564                 hint += (i + 2) & ~1;
 565
 566                 /* Head lock still held and bh's disabled */
 567                 inet_bind_hash(sk, tb, port);
 568                 if (sk_unhashed(sk)) {
 569                         inet_sk(sk)->inet_sport = htons(port);
 570                         __inet_hash_nolisten(sk, (struct sock *)tw);
 571                 }
 572                 if (tw)
 573                         inet_twsk_bind_unhash(tw, hinfo);
 574                 spin_unlock(&head->lock);
 575
 576                 if (tw)
 577                         inet_twsk_deschedule_put(tw);
 578
 579                 ret = 0;
 580                 goto out;
 581         }
 582
 583         head = &hinfo->bhash[inet_bhashfn(net, snum, hinfo->bhash_size)];
 584         tb  = inet_csk(sk)->icsk_bind_hash;
 585         spin_lock_bh(&head->lock);
 586         if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
 587                 __inet_hash_nolisten(sk, NULL);
 588                 spin_unlock_bh(&head->lock);
 589                 return 0;
 590         } else {
 591                 spin_unlock(&head->lock);
 592                 /* No definite answer... Walk to established hash table */
 593                 ret = check_established(death_row, sk, snum, NULL);
 594 out:
 595                 local_bh_enable();
 596                 return ret;
 597         }
 598 }
 599
 600 /*
 601  * Bind a port for a connect operation and hash it.
 602  */
 603 int inet_hash_connect(struct inet_timewait_death_row *death_row,
 604                       struct sock *sk)
 605 {
 606         u32 port_offset = 0;
 607
 608         if (!inet_sk(sk)->inet_num)
 609                 port_offset = inet_sk_port_offset(sk);
 610         return __inet_hash_connect(death_row, sk, port_offset,
 611                                    __inet_check_established);
 612 }
 613 EXPORT_SYMBOL_GPL(inet_hash_connect);
 614
 615 void inet_hashinfo_init(struct inet_hashinfo *h)
 616 {
 617         int i;
 618
 619         for (i = 0; i < INET_LHTABLE_SIZE; i++) {
 620                 spin_lock_init(&h->listening_hash[i].lock);
 621                 INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].head,
 622                                       i + LISTENING_NULLS_BASE);
 623                 }
 624 }
 625 EXPORT_SYMBOL_GPL(inet_hashinfo_init);
 626
 627 int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
 628 {
 629         unsigned int locksz = sizeof(spinlock_t);
 630         unsigned int i, nblocks = 1;
 631
 632         if (locksz != 0) {
 633                 /* allocate 2 cache lines or at least one spinlock per cpu */
 634                 nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U);
 635                 nblocks = roundup_pow_of_two(nblocks * num_possible_cpus());
 636
 637                 /* no more locks than number of hash buckets */
 638                 nblocks = min(nblocks, hashinfo->ehash_mask + 1);
 639
 640                 hashinfo->ehash_locks = kmalloc_array(nblocks, locksz,
 641                                                       GFP_KERNEL | __GFP_NOWARN);
 642                 if (!hashinfo->ehash_locks)
 643                         hashinfo->ehash_locks = vmalloc(nblocks * locksz);
 644
 645                 if (!hashinfo->ehash_locks)
 646                         return -ENOMEM;
 647
 648                 for (i = 0; i < nblocks; i++)
 649                         spin_lock_init(&hashinfo->ehash_locks[i]);
 650         }
 651         hashinfo->ehash_locks_mask = nblocks - 1;
 652         return 0;
 653 }
 654 EXPORT_SYMBOL_GPL(inet_ehash_locks_alloc);