fs/lockd/host.c

   1 /*
   2  * linux/fs/lockd/host.c
   3  *
   4  * Management for NLM peer hosts. The nlm_host struct is shared
   5  * between client and server implementation. The only reason to
   6  * do so is to reduce code bloat.
   7  *
   8  * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/slab.h>
  13 #include <linux/in.h>
  14 #include <linux/in6.h>
  15 #include <linux/sunrpc/clnt.h>
  16 #include <linux/sunrpc/svc.h>
  17 #include <linux/lockd/lockd.h>
  18 #include <linux/lockd/sm_inter.h>
  19 #include <linux/mutex.h>
  20
  21 #include <net/ipv6.h>
  22
  23 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
  24 #define NLM_HOST_NRHASH         32
  25 #define NLM_HOST_REBIND         (60 * HZ)
  26 #define NLM_HOST_EXPIRE         (300 * HZ)
  27 #define NLM_HOST_COLLECT        (120 * HZ)
  28
  29 static struct hlist_head        nlm_hosts[NLM_HOST_NRHASH];
  30 static unsigned long            next_gc;
  31 static int                      nrhosts;
  32 static DEFINE_MUTEX(nlm_host_mutex);
  33
  34 static void                     nlm_gc_hosts(void);
  35 static struct nsm_handle        *nsm_find(const struct sockaddr *sap,
  36                                                 const size_t salen,
  37                                                 const char *hostname,
  38                                                 const size_t hostname_len,
  39                                                 const int create);
  40
  41 struct nlm_lookup_host_info {
  42         const int               server;         /* search for server|client */
  43         const struct sockaddr_in *sin;          /* address to search for */
  44         const unsigned short    protocol;       /* transport to search for*/
  45         const u32               version;        /* NLM version to search for */
  46         const char              *hostname;      /* remote's hostname */
  47         const size_t            hostname_len;   /* it's length */
  48         const struct sockaddr_in *src_sin;      /* our address (optional) */
  49         const size_t            src_len;        /* it's length */
  50 };
  51
  52 /*
  53  * Hash function must work well on big- and little-endian platforms
  54  */
  55 static unsigned int __nlm_hash32(const __be32 n)
  56 {
  57         unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
  58         return hash ^ (hash >> 8);
  59 }
  60
  61 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
  62 {
  63         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
  64         return __nlm_hash32(sin->sin_addr.s_addr);
  65 }
  66
  67 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
  68 {
  69         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  70         const struct in6_addr addr = sin6->sin6_addr;
  71         return __nlm_hash32(addr.s6_addr32[0]) ^
  72                __nlm_hash32(addr.s6_addr32[1]) ^
  73                __nlm_hash32(addr.s6_addr32[2]) ^
  74                __nlm_hash32(addr.s6_addr32[3]);
  75 }
  76
  77 static unsigned int nlm_hash_address(const struct sockaddr *sap)
  78 {
  79         unsigned int hash;
  80
  81         switch (sap->sa_family) {
  82         case AF_INET:
  83                 hash = __nlm_hash_addr4(sap);
  84                 break;
  85         case AF_INET6:
  86                 hash = __nlm_hash_addr6(sap);
  87                 break;
  88         default:
  89                 hash = 0;
  90         }
  91         return hash & (NLM_HOST_NRHASH - 1);
  92 }
  93
  94 static void nlm_clear_port(struct sockaddr *sap)
  95 {
  96         switch (sap->sa_family) {
  97         case AF_INET:
  98                 ((struct sockaddr_in *)sap)->sin_port = 0;
  99                 break;
 100         case AF_INET6:
 101                 ((struct sockaddr_in6 *)sap)->sin6_port = 0;
 102                 break;
 103         }
 104 }
 105
 106 static void nlm_display_address(const struct sockaddr *sap,
 107                                 char *buf, const size_t len)
 108 {
 109         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 110         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
 111
 112         switch (sap->sa_family) {
 113         case AF_UNSPEC:
 114                 snprintf(buf, len, "unspecified");
 115                 break;
 116         case AF_INET:
 117                 snprintf(buf, len, NIPQUAD_FMT, NIPQUAD(sin->sin_addr.s_addr));
 118                 break;
 119         case AF_INET6:
 120                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 121                         snprintf(buf, len, NIPQUAD_FMT,
 122                                  NIPQUAD(sin6->sin6_addr.s6_addr32[3]));
 123                 else
 124                         snprintf(buf, len, NIP6_FMT, NIP6(sin6->sin6_addr));
 125                 break;
 126         default:
 127                 snprintf(buf, len, "unsupported address family");
 128                 break;
 129         }
 130 }
 131
 132 /*
 133  * Common host lookup routine for server & client
 134  */
 135 static struct nlm_host *nlm_lookup_host(struct nlm_lookup_host_info *ni)
 136 {
 137         struct hlist_head *chain;
 138         struct hlist_node *pos;
 139         struct nlm_host *host;
 140         struct nsm_handle *nsm = NULL;
 141
 142         mutex_lock(&nlm_host_mutex);
 143
 144         if (time_after_eq(jiffies, next_gc))
 145                 nlm_gc_hosts();
 146
 147         /* We may keep several nlm_host objects for a peer, because each
 148          * nlm_host is identified by
 149          * (address, protocol, version, server/client)
 150          * We could probably simplify this a little by putting all those
 151          * different NLM rpc_clients into one single nlm_host object.
 152          * This would allow us to have one nlm_host per address.
 153          */
 154         chain = &nlm_hosts[nlm_hash_address((struct sockaddr *)ni->sin)];
 155         hlist_for_each_entry(host, pos, chain, h_hash) {
 156                 if (!nlm_cmp_addr(nlm_addr(host), (struct sockaddr *)ni->sin))
 157                         continue;
 158
 159                 /* See if we have an NSM handle for this client */
 160                 if (!nsm)
 161                         nsm = host->h_nsmhandle;
 162
 163                 if (host->h_proto != ni->protocol)
 164                         continue;
 165                 if (host->h_version != ni->version)
 166                         continue;
 167                 if (host->h_server != ni->server)
 168                         continue;
 169                 if (!nlm_cmp_addr(nlm_srcaddr(host),
 170                                         (struct sockaddr *)ni->src_sin))
 171                         continue;
 172
 173                 /* Move to head of hash chain. */
 174                 hlist_del(&host->h_hash);
 175                 hlist_add_head(&host->h_hash, chain);
 176
 177                 nlm_get_host(host);
 178                 dprintk("lockd: nlm_lookup_host found host %s (%s)\n",
 179                                 host->h_name, host->h_addrbuf);
 180                 goto out;
 181         }
 182
 183         /*
 184          * The host wasn't in our hash table.  If we don't
 185          * have an NSM handle for it yet, create one.
 186          */
 187         if (nsm)
 188                 atomic_inc(&nsm->sm_count);
 189         else {
 190                 host = NULL;
 191                 nsm = nsm_find((struct sockaddr *)ni->sin,
 192                                 sizeof(struct sockaddr_in),
 193                                 ni->hostname, ni->hostname_len, 1);
 194                 if (!nsm) {
 195                         dprintk("lockd: nlm_lookup_host failed; "
 196                                 "no nsm handle\n");
 197                         goto out;
 198                 }
 199         }
 200
 201         host = kzalloc(sizeof(*host), GFP_KERNEL);
 202         if (!host) {
 203                 nsm_release(nsm);
 204                 dprintk("lockd: nlm_lookup_host failed; no memory\n");
 205                 goto out;
 206         }
 207         host->h_name       = nsm->sm_name;
 208         memcpy(nlm_addr(host), ni->sin, sizeof(struct sockaddr_in));
 209         host->h_addrlen = sizeof(struct sockaddr_in);
 210         nlm_clear_port(nlm_addr(host));
 211         memcpy(nlm_srcaddr(host), ni->src_sin, sizeof(struct sockaddr_in));
 212         host->h_version    = ni->version;
 213         host->h_proto      = ni->protocol;
 214         host->h_rpcclnt    = NULL;
 215         mutex_init(&host->h_mutex);
 216         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 217         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 218         atomic_set(&host->h_count, 1);
 219         init_waitqueue_head(&host->h_gracewait);
 220         init_rwsem(&host->h_rwsem);
 221         host->h_state      = 0;                 /* pseudo NSM state */
 222         host->h_nsmstate   = 0;                 /* real NSM state */
 223         host->h_nsmhandle  = nsm;
 224         host->h_server     = ni->server;
 225         hlist_add_head(&host->h_hash, chain);
 226         INIT_LIST_HEAD(&host->h_lockowners);
 227         spin_lock_init(&host->h_lock);
 228         INIT_LIST_HEAD(&host->h_granted);
 229         INIT_LIST_HEAD(&host->h_reclaim);
 230
 231         nrhosts++;
 232
 233         nlm_display_address((struct sockaddr *)&host->h_addr,
 234                                 host->h_addrbuf, sizeof(host->h_addrbuf));
 235         nlm_display_address((struct sockaddr *)&host->h_srcaddr,
 236                                 host->h_srcaddrbuf, sizeof(host->h_srcaddrbuf));
 237
 238         dprintk("lockd: nlm_lookup_host created host %s\n",
 239                         host->h_name);
 240
 241 out:
 242         mutex_unlock(&nlm_host_mutex);
 243         return host;
 244 }
 245
 246 /*
 247  * Destroy a host
 248  */
 249 static void
 250 nlm_destroy_host(struct nlm_host *host)
 251 {
 252         struct rpc_clnt *clnt;
 253
 254         BUG_ON(!list_empty(&host->h_lockowners));
 255         BUG_ON(atomic_read(&host->h_count));
 256
 257         /*
 258          * Release NSM handle and unmonitor host.
 259          */
 260         nsm_unmonitor(host);
 261
 262         clnt = host->h_rpcclnt;
 263         if (clnt != NULL)
 264                 rpc_shutdown_client(clnt);
 265         kfree(host);
 266 }
 267
 268 /*
 269  * Find an NLM server handle in the cache. If there is none, create it.
 270  */
 271 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr_in *sin,
 272                                      int proto, u32 version,
 273                                      const char *hostname,
 274                                      unsigned int hostname_len)
 275 {
 276         const struct sockaddr_in source = {
 277                 .sin_family     = AF_UNSPEC,
 278         };
 279         struct nlm_lookup_host_info ni = {
 280                 .server         = 0,
 281                 .sin            = sin,
 282                 .protocol       = proto,
 283                 .version        = version,
 284                 .hostname       = hostname,
 285                 .hostname_len   = hostname_len,
 286                 .src_sin        = &source,
 287         };
 288
 289         dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
 290                         (hostname ? hostname : "<none>"), version,
 291                         (proto == IPPROTO_UDP ? "udp" : "tcp"));
 292
 293         return nlm_lookup_host(&ni);
 294 }
 295
 296 /*
 297  * Find an NLM client handle in the cache. If there is none, create it.
 298  */
 299 struct nlm_host *
 300 nlmsvc_lookup_host(struct svc_rqst *rqstp,
 301                         const char *hostname, unsigned int hostname_len)
 302 {
 303         const struct sockaddr_in source = {
 304                 .sin_family     = AF_INET,
 305                 .sin_addr       = rqstp->rq_daddr.addr,
 306         };
 307         struct nlm_lookup_host_info ni = {
 308                 .server         = 1,
 309                 .sin            = svc_addr_in(rqstp),
 310                 .protocol       = rqstp->rq_prot,
 311                 .version        = rqstp->rq_vers,
 312                 .hostname       = hostname,
 313                 .hostname_len   = hostname_len,
 314                 .src_sin        = &source,
 315         };
 316
 317         dprintk("lockd: %s(host='%*s', vers=%u, proto=%s)\n", __func__,
 318                         (int)hostname_len, hostname, rqstp->rq_vers,
 319                         (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
 320
 321         return nlm_lookup_host(&ni);
 322 }
 323
 324 /*
 325  * Create the NLM RPC client for an NLM peer
 326  */
 327 struct rpc_clnt *
 328 nlm_bind_host(struct nlm_host *host)
 329 {
 330         struct rpc_clnt *clnt;
 331
 332         dprintk("lockd: nlm_bind_host %s (%s), my addr=%s\n",
 333                         host->h_name, host->h_addrbuf, host->h_srcaddrbuf);
 334
 335         /* Lock host handle */
 336         mutex_lock(&host->h_mutex);
 337
 338         /* If we've already created an RPC client, check whether
 339          * RPC rebind is required
 340          */
 341         if ((clnt = host->h_rpcclnt) != NULL) {
 342                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 343                         rpc_force_rebind(clnt);
 344                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 345                         dprintk("lockd: next rebind in %lu jiffies\n",
 346                                         host->h_nextrebind - jiffies);
 347                 }
 348         } else {
 349                 unsigned long increment = nlmsvc_timeout;
 350                 struct rpc_timeout timeparms = {
 351                         .to_initval     = increment,
 352                         .to_increment   = increment,
 353                         .to_maxval      = increment * 6UL,
 354                         .to_retries     = 5U,
 355                 };
 356                 struct rpc_create_args args = {
 357                         .protocol       = host->h_proto,
 358                         .address        = nlm_addr(host),
 359                         .addrsize       = host->h_addrlen,
 360                         .saddress       = nlm_srcaddr(host),
 361                         .timeout        = &timeparms,
 362                         .servername     = host->h_name,
 363                         .program        = &nlm_program,
 364                         .version        = host->h_version,
 365                         .authflavor     = RPC_AUTH_UNIX,
 366                         .flags          = (RPC_CLNT_CREATE_NOPING |
 367                                            RPC_CLNT_CREATE_AUTOBIND),
 368                 };
 369
 370                 /*
 371                  * lockd retries server side blocks automatically so we want
 372                  * those to be soft RPC calls. Client side calls need to be
 373                  * hard RPC tasks.
 374                  */
 375                 if (!host->h_server)
 376                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
 377
 378                 clnt = rpc_create(&args);
 379                 if (!IS_ERR(clnt))
 380                         host->h_rpcclnt = clnt;
 381                 else {
 382                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 383                         clnt = NULL;
 384                 }
 385         }
 386
 387         mutex_unlock(&host->h_mutex);
 388         return clnt;
 389 }
 390
 391 /*
 392  * Force a portmap lookup of the remote lockd port
 393  */
 394 void
 395 nlm_rebind_host(struct nlm_host *host)
 396 {
 397         dprintk("lockd: rebind host %s\n", host->h_name);
 398         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 399                 rpc_force_rebind(host->h_rpcclnt);
 400                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 401         }
 402 }
 403
 404 /*
 405  * Increment NLM host count
 406  */
 407 struct nlm_host * nlm_get_host(struct nlm_host *host)
 408 {
 409         if (host) {
 410                 dprintk("lockd: get host %s\n", host->h_name);
 411                 atomic_inc(&host->h_count);
 412                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 413         }
 414         return host;
 415 }
 416
 417 /*
 418  * Release NLM host after use
 419  */
 420 void nlm_release_host(struct nlm_host *host)
 421 {
 422         if (host != NULL) {
 423                 dprintk("lockd: release host %s\n", host->h_name);
 424                 BUG_ON(atomic_read(&host->h_count) < 0);
 425                 if (atomic_dec_and_test(&host->h_count)) {
 426                         BUG_ON(!list_empty(&host->h_lockowners));
 427                         BUG_ON(!list_empty(&host->h_granted));
 428                         BUG_ON(!list_empty(&host->h_reclaim));
 429                 }
 430         }
 431 }
 432
 433 /*
 434  * We were notified that the host indicated by address &sin
 435  * has rebooted.
 436  * Release all resources held by that peer.
 437  */
 438 void nlm_host_rebooted(const struct sockaddr_in *sin,
 439                                 const char *hostname,
 440                                 unsigned int hostname_len,
 441                                 u32 new_state)
 442 {
 443         struct hlist_head *chain;
 444         struct hlist_node *pos;
 445         struct nsm_handle *nsm;
 446         struct nlm_host *host;
 447
 448         nsm = nsm_find((struct sockaddr *)sin, sizeof(*sin),
 449                         hostname, hostname_len, 0);
 450         if (nsm == NULL) {
 451                 dprintk("lockd: never saw rebooted peer '%.*s' before\n",
 452                                 hostname_len, hostname);
 453                 return;
 454         }
 455
 456         dprintk("lockd: nlm_host_rebooted(%.*s, %s)\n",
 457                         hostname_len, hostname, nsm->sm_addrbuf);
 458
 459         /* When reclaiming locks on this peer, make sure that
 460          * we set up a new notification */
 461         nsm->sm_monitored = 0;
 462
 463         /* Mark all hosts tied to this NSM state as having rebooted.
 464          * We run the loop repeatedly, because we drop the host table
 465          * lock for this.
 466          * To avoid processing a host several times, we match the nsmstate.
 467          */
 468 again:  mutex_lock(&nlm_host_mutex);
 469         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 470                 hlist_for_each_entry(host, pos, chain, h_hash) {
 471                         if (host->h_nsmhandle == nsm
 472                          && host->h_nsmstate != new_state) {
 473                                 host->h_nsmstate = new_state;
 474                                 host->h_state++;
 475
 476                                 nlm_get_host(host);
 477                                 mutex_unlock(&nlm_host_mutex);
 478
 479                                 if (host->h_server) {
 480                                         /* We're server for this guy, just ditch
 481                                          * all the locks he held. */
 482                                         nlmsvc_free_host_resources(host);
 483                                 } else {
 484                                         /* He's the server, initiate lock recovery. */
 485                                         nlmclnt_recovery(host);
 486                                 }
 487
 488                                 nlm_release_host(host);
 489                                 goto again;
 490                         }
 491                 }
 492         }
 493
 494         mutex_unlock(&nlm_host_mutex);
 495 }
 496
 497 /*
 498  * Shut down the hosts module.
 499  * Note that this routine is called only at server shutdown time.
 500  */
 501 void
 502 nlm_shutdown_hosts(void)
 503 {
 504         struct hlist_head *chain;
 505         struct hlist_node *pos;
 506         struct nlm_host *host;
 507
 508         dprintk("lockd: shutting down host module\n");
 509         mutex_lock(&nlm_host_mutex);
 510
 511         /* First, make all hosts eligible for gc */
 512         dprintk("lockd: nuking all hosts...\n");
 513         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 514                 hlist_for_each_entry(host, pos, chain, h_hash) {
 515                         host->h_expires = jiffies - 1;
 516                         if (host->h_rpcclnt) {
 517                                 rpc_shutdown_client(host->h_rpcclnt);
 518                                 host->h_rpcclnt = NULL;
 519                         }
 520                 }
 521         }
 522
 523         /* Then, perform a garbage collection pass */
 524         nlm_gc_hosts();
 525         mutex_unlock(&nlm_host_mutex);
 526
 527         /* complain if any hosts are left */
 528         if (nrhosts) {
 529                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 530                 dprintk("lockd: %d hosts left:\n", nrhosts);
 531                 for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 532                         hlist_for_each_entry(host, pos, chain, h_hash) {
 533                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 534                                         host->h_name, atomic_read(&host->h_count),
 535                                         host->h_inuse, host->h_expires);
 536                         }
 537                 }
 538         }
 539 }
 540
 541 /*
 542  * Garbage collect any unused NLM hosts.
 543  * This GC combines reference counting for async operations with
 544  * mark & sweep for resources held by remote clients.
 545  */
 546 static void
 547 nlm_gc_hosts(void)
 548 {
 549         struct hlist_head *chain;
 550         struct hlist_node *pos, *next;
 551         struct nlm_host *host;
 552
 553         dprintk("lockd: host garbage collection\n");
 554         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 555                 hlist_for_each_entry(host, pos, chain, h_hash)
 556                         host->h_inuse = 0;
 557         }
 558
 559         /* Mark all hosts that hold locks, blocks or shares */
 560         nlmsvc_mark_resources();
 561
 562         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 563                 hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
 564                         if (atomic_read(&host->h_count) || host->h_inuse
 565                          || time_before(jiffies, host->h_expires)) {
 566                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
 567                                         host->h_name, atomic_read(&host->h_count),
 568                                         host->h_inuse, host->h_expires);
 569                                 continue;
 570                         }
 571                         dprintk("lockd: delete host %s\n", host->h_name);
 572                         hlist_del_init(&host->h_hash);
 573
 574                         nlm_destroy_host(host);
 575                         nrhosts--;
 576                 }
 577         }
 578
 579         next_gc = jiffies + NLM_HOST_COLLECT;
 580 }
 581
 582
 583 /*
 584  * Manage NSM handles
 585  */
 586 static LIST_HEAD(nsm_handles);
 587 static DEFINE_SPINLOCK(nsm_lock);
 588
 589 static struct nsm_handle *nsm_find(const struct sockaddr *sap,
 590                                    const size_t salen,
 591                                    const char *hostname,
 592                                    const size_t hostname_len,
 593                                    const int create)
 594 {
 595         struct nsm_handle *nsm = NULL;
 596         struct nsm_handle *pos;
 597
 598         if (!sap)
 599                 return NULL;
 600
 601         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
 602                 if (printk_ratelimit()) {
 603                         printk(KERN_WARNING "Invalid hostname \"%.*s\" "
 604                                             "in NFS lock request\n",
 605                                 (int)hostname_len, hostname);
 606                 }
 607                 return NULL;
 608         }
 609
 610 retry:
 611         spin_lock(&nsm_lock);
 612         list_for_each_entry(pos, &nsm_handles, sm_link) {
 613
 614                 if (hostname && nsm_use_hostnames) {
 615                         if (strlen(pos->sm_name) != hostname_len
 616                          || memcmp(pos->sm_name, hostname, hostname_len))
 617                                 continue;
 618                 } else if (!nlm_cmp_addr(nsm_addr(pos), sap))
 619                         continue;
 620                 atomic_inc(&pos->sm_count);
 621                 kfree(nsm);
 622                 nsm = pos;
 623                 goto found;
 624         }
 625         if (nsm) {
 626                 list_add(&nsm->sm_link, &nsm_handles);
 627                 goto found;
 628         }
 629         spin_unlock(&nsm_lock);
 630
 631         if (!create)
 632                 return NULL;
 633
 634         nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
 635         if (nsm == NULL)
 636                 return NULL;
 637
 638         memcpy(nsm_addr(nsm), sap, salen);
 639         nsm->sm_addrlen = salen;
 640         nsm->sm_name = (char *) (nsm + 1);
 641         memcpy(nsm->sm_name, hostname, hostname_len);
 642         nsm->sm_name[hostname_len] = '\0';
 643         nlm_display_address((struct sockaddr *)&nsm->sm_addr,
 644                                 nsm->sm_addrbuf, sizeof(nsm->sm_addrbuf));
 645         atomic_set(&nsm->sm_count, 1);
 646         goto retry;
 647
 648 found:
 649         spin_unlock(&nsm_lock);
 650         return nsm;
 651 }
 652
 653 /*
 654  * Release an NSM handle
 655  */
 656 void
 657 nsm_release(struct nsm_handle *nsm)
 658 {
 659         if (!nsm)
 660                 return;
 661         if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
 662                 list_del(&nsm->sm_link);
 663                 spin_unlock(&nsm_lock);
 664                 kfree(nsm);
 665         }
 666 }