net/sunrpc/clnt.c

   1 /*
   2  *  linux/net/sunrpc/clnt.c
   3  *
   4  *  This file contains the high-level RPC interface.
   5  *  It is modeled as a finite state machine to support both synchronous
   6  *  and asynchronous requests.
   7  *
   8  *  -   RPC header generation and argument serialization.
   9  *  -   Credential refresh.
  10  *  -   TCP connect handling.
  11  *  -   Retry of operation when it is suspected the operation failed because
  12  *      of uid squashing on the server, or when the credentials were stale
  13  *      and need to be refreshed, or when a packet was damaged in transit.
  14  *      This may be have to be moved to the VFS layer.
  15  *
  16  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  17  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  18  */
  19
  20
  21 #include <linux/module.h>
  22 #include <linux/types.h>
  23 #include <linux/kallsyms.h>
  24 #include <linux/mm.h>
  25 #include <linux/namei.h>
  26 #include <linux/mount.h>
  27 #include <linux/slab.h>
  28 #include <linux/rcupdate.h>
  29 #include <linux/utsname.h>
  30 #include <linux/workqueue.h>
  31 #include <linux/in.h>
  32 #include <linux/in6.h>
  33 #include <linux/un.h>
  34
  35 #include <linux/sunrpc/clnt.h>
  36 #include <linux/sunrpc/addr.h>
  37 #include <linux/sunrpc/rpc_pipe_fs.h>
  38 #include <linux/sunrpc/metrics.h>
  39 #include <linux/sunrpc/bc_xprt.h>
  40 #include <trace/events/sunrpc.h>
  41
  42 #include "sunrpc.h"
  43 #include "netns.h"
  44
  45 #ifdef RPC_DEBUG
  46 # define RPCDBG_FACILITY        RPCDBG_CALL
  47 #endif
  48
  49 #define dprint_status(t)                                        \
  50         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  51                         __func__, t->tk_status)
  52
  53 /*
  54  * All RPC clients are linked into this list
  55  */
  56
  57 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  58
  59
  60 static void     call_start(struct rpc_task *task);
  61 static void     call_reserve(struct rpc_task *task);
  62 static void     call_reserveresult(struct rpc_task *task);
  63 static void     call_allocate(struct rpc_task *task);
  64 static void     call_decode(struct rpc_task *task);
  65 static void     call_bind(struct rpc_task *task);
  66 static void     call_bind_status(struct rpc_task *task);
  67 static void     call_transmit(struct rpc_task *task);
  68 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
  69 static void     call_bc_transmit(struct rpc_task *task);
  70 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
  71 static void     call_status(struct rpc_task *task);
  72 static void     call_transmit_status(struct rpc_task *task);
  73 static void     call_refresh(struct rpc_task *task);
  74 static void     call_refreshresult(struct rpc_task *task);
  75 static void     call_timeout(struct rpc_task *task);
  76 static void     call_connect(struct rpc_task *task);
  77 static void     call_connect_status(struct rpc_task *task);
  78
  79 static __be32   *rpc_encode_header(struct rpc_task *task);
  80 static __be32   *rpc_verify_header(struct rpc_task *task);
  81 static int      rpc_ping(struct rpc_clnt *clnt);
  82
  83 static void rpc_register_client(struct rpc_clnt *clnt)
  84 {
  85         struct net *net = rpc_net_ns(clnt);
  86         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
  87
  88         spin_lock(&sn->rpc_client_lock);
  89         list_add(&clnt->cl_clients, &sn->all_clients);
  90         spin_unlock(&sn->rpc_client_lock);
  91 }
  92
  93 static void rpc_unregister_client(struct rpc_clnt *clnt)
  94 {
  95         struct net *net = rpc_net_ns(clnt);
  96         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
  97
  98         spin_lock(&sn->rpc_client_lock);
  99         list_del(&clnt->cl_clients);
 100         spin_unlock(&sn->rpc_client_lock);
 101 }
 102
 103 static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
 104 {
 105         rpc_remove_client_dir(clnt);
 106 }
 107
 108 static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
 109 {
 110         struct net *net = rpc_net_ns(clnt);
 111         struct super_block *pipefs_sb;
 112
 113         pipefs_sb = rpc_get_sb_net(net);
 114         if (pipefs_sb) {
 115                 __rpc_clnt_remove_pipedir(clnt);
 116                 rpc_put_sb_net(net);
 117         }
 118 }
 119
 120 static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
 121                                     struct rpc_clnt *clnt)
 122 {
 123         static uint32_t clntid;
 124         const char *dir_name = clnt->cl_program->pipe_dir_name;
 125         char name[15];
 126         struct dentry *dir, *dentry;
 127
 128         dir = rpc_d_lookup_sb(sb, dir_name);
 129         if (dir == NULL) {
 130                 pr_info("RPC: pipefs directory doesn't exist: %s\n", dir_name);
 131                 return dir;
 132         }
 133         for (;;) {
 134                 snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
 135                 name[sizeof(name) - 1] = '\0';
 136                 dentry = rpc_create_client_dir(dir, name, clnt);
 137                 if (!IS_ERR(dentry))
 138                         break;
 139                 if (dentry == ERR_PTR(-EEXIST))
 140                         continue;
 141                 printk(KERN_INFO "RPC: Couldn't create pipefs entry"
 142                                 " %s/%s, error %ld\n",
 143                                 dir_name, name, PTR_ERR(dentry));
 144                 break;
 145         }
 146         dput(dir);
 147         return dentry;
 148 }
 149
 150 static int
 151 rpc_setup_pipedir(struct super_block *pipefs_sb, struct rpc_clnt *clnt)
 152 {
 153         struct dentry *dentry;
 154
 155         if (clnt->cl_program->pipe_dir_name != NULL) {
 156                 dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt);
 157                 if (IS_ERR(dentry))
 158                         return PTR_ERR(dentry);
 159         }
 160         return 0;
 161 }
 162
 163 static int rpc_clnt_skip_event(struct rpc_clnt *clnt, unsigned long event)
 164 {
 165         if (clnt->cl_program->pipe_dir_name == NULL)
 166                 return 1;
 167
 168         switch (event) {
 169         case RPC_PIPEFS_MOUNT:
 170                 if (clnt->cl_pipedir_objects.pdh_dentry != NULL)
 171                         return 1;
 172                 if (atomic_read(&clnt->cl_count) == 0)
 173                         return 1;
 174                 break;
 175         case RPC_PIPEFS_UMOUNT:
 176                 if (clnt->cl_pipedir_objects.pdh_dentry == NULL)
 177                         return 1;
 178                 break;
 179         }
 180         return 0;
 181 }
 182
 183 static int __rpc_clnt_handle_event(struct rpc_clnt *clnt, unsigned long event,
 184                                    struct super_block *sb)
 185 {
 186         struct dentry *dentry;
 187         int err = 0;
 188
 189         switch (event) {
 190         case RPC_PIPEFS_MOUNT:
 191                 dentry = rpc_setup_pipedir_sb(sb, clnt);
 192                 if (!dentry)
 193                         return -ENOENT;
 194                 if (IS_ERR(dentry))
 195                         return PTR_ERR(dentry);
 196                 break;
 197         case RPC_PIPEFS_UMOUNT:
 198                 __rpc_clnt_remove_pipedir(clnt);
 199                 break;
 200         default:
 201                 printk(KERN_ERR "%s: unknown event: %ld\n", __func__, event);
 202                 return -ENOTSUPP;
 203         }
 204         return err;
 205 }
 206
 207 static int __rpc_pipefs_event(struct rpc_clnt *clnt, unsigned long event,
 208                                 struct super_block *sb)
 209 {
 210         int error = 0;
 211
 212         for (;; clnt = clnt->cl_parent) {
 213                 if (!rpc_clnt_skip_event(clnt, event))
 214                         error = __rpc_clnt_handle_event(clnt, event, sb);
 215                 if (error || clnt == clnt->cl_parent)
 216                         break;
 217         }
 218         return error;
 219 }
 220
 221 static struct rpc_clnt *rpc_get_client_for_event(struct net *net, int event)
 222 {
 223         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 224         struct rpc_clnt *clnt;
 225
 226         spin_lock(&sn->rpc_client_lock);
 227         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
 228                 if (rpc_clnt_skip_event(clnt, event))
 229                         continue;
 230                 spin_unlock(&sn->rpc_client_lock);
 231                 return clnt;
 232         }
 233         spin_unlock(&sn->rpc_client_lock);
 234         return NULL;
 235 }
 236
 237 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 238                             void *ptr)
 239 {
 240         struct super_block *sb = ptr;
 241         struct rpc_clnt *clnt;
 242         int error = 0;
 243
 244         while ((clnt = rpc_get_client_for_event(sb->s_fs_info, event))) {
 245                 error = __rpc_pipefs_event(clnt, event, sb);
 246                 if (error)
 247                         break;
 248         }
 249         return error;
 250 }
 251
 252 static struct notifier_block rpc_clients_block = {
 253         .notifier_call  = rpc_pipefs_event,
 254         .priority       = SUNRPC_PIPEFS_RPC_PRIO,
 255 };
 256
 257 int rpc_clients_notifier_register(void)
 258 {
 259         return rpc_pipefs_notifier_register(&rpc_clients_block);
 260 }
 261
 262 void rpc_clients_notifier_unregister(void)
 263 {
 264         return rpc_pipefs_notifier_unregister(&rpc_clients_block);
 265 }
 266
 267 static struct rpc_xprt *rpc_clnt_set_transport(struct rpc_clnt *clnt,
 268                 struct rpc_xprt *xprt,
 269                 const struct rpc_timeout *timeout)
 270 {
 271         struct rpc_xprt *old;
 272
 273         spin_lock(&clnt->cl_lock);
 274         old = rcu_dereference_protected(clnt->cl_xprt,
 275                         lockdep_is_held(&clnt->cl_lock));
 276
 277         if (!xprt_bound(xprt))
 278                 clnt->cl_autobind = 1;
 279
 280         clnt->cl_timeout = timeout;
 281         rcu_assign_pointer(clnt->cl_xprt, xprt);
 282         spin_unlock(&clnt->cl_lock);
 283
 284         return old;
 285 }
 286
 287 static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename)
 288 {
 289         clnt->cl_nodelen = strlen(nodename);
 290         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 291                 clnt->cl_nodelen = UNX_MAXNODENAME;
 292         memcpy(clnt->cl_nodename, nodename, clnt->cl_nodelen);
 293 }
 294
 295 static int rpc_client_register(struct rpc_clnt *clnt,
 296                                rpc_authflavor_t pseudoflavor,
 297                                const char *client_name)
 298 {
 299         struct rpc_auth_create_args auth_args = {
 300                 .pseudoflavor = pseudoflavor,
 301                 .target_name = client_name,
 302         };
 303         struct rpc_auth *auth;
 304         struct net *net = rpc_net_ns(clnt);
 305         struct super_block *pipefs_sb;
 306         int err;
 307
 308         pipefs_sb = rpc_get_sb_net(net);
 309         if (pipefs_sb) {
 310                 err = rpc_setup_pipedir(pipefs_sb, clnt);
 311                 if (err)
 312                         goto out;
 313         }
 314
 315         rpc_register_client(clnt);
 316         if (pipefs_sb)
 317                 rpc_put_sb_net(net);
 318
 319         auth = rpcauth_create(&auth_args, clnt);
 320         if (IS_ERR(auth)) {
 321                 dprintk("RPC:       Couldn't create auth handle (flavor %u)\n",
 322                                 pseudoflavor);
 323                 err = PTR_ERR(auth);
 324                 goto err_auth;
 325         }
 326         return 0;
 327 err_auth:
 328         pipefs_sb = rpc_get_sb_net(net);
 329         rpc_unregister_client(clnt);
 330         __rpc_clnt_remove_pipedir(clnt);
 331 out:
 332         if (pipefs_sb)
 333                 rpc_put_sb_net(net);
 334         return err;
 335 }
 336
 337 static DEFINE_IDA(rpc_clids);
 338
 339 static int rpc_alloc_clid(struct rpc_clnt *clnt)
 340 {
 341         int clid;
 342
 343         clid = ida_simple_get(&rpc_clids, 0, 0, GFP_KERNEL);
 344         if (clid < 0)
 345                 return clid;
 346         clnt->cl_clid = clid;
 347         return 0;
 348 }
 349
 350 static void rpc_free_clid(struct rpc_clnt *clnt)
 351 {
 352         ida_simple_remove(&rpc_clids, clnt->cl_clid);
 353 }
 354
 355 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args,
 356                 struct rpc_xprt *xprt,
 357                 struct rpc_clnt *parent)
 358 {
 359         const struct rpc_program *program = args->program;
 360         const struct rpc_version *version;
 361         struct rpc_clnt *clnt = NULL;
 362         const struct rpc_timeout *timeout;
 363         int err;
 364
 365         /* sanity check the name before trying to print it */
 366         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 367                         program->name, args->servername, xprt);
 368
 369         err = rpciod_up();
 370         if (err)
 371                 goto out_no_rpciod;
 372
 373         err = -EINVAL;
 374         if (args->version >= program->nrvers)
 375                 goto out_err;
 376         version = program->version[args->version];
 377         if (version == NULL)
 378                 goto out_err;
 379
 380         err = -ENOMEM;
 381         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 382         if (!clnt)
 383                 goto out_err;
 384         clnt->cl_parent = parent ? : clnt;
 385
 386         err = rpc_alloc_clid(clnt);
 387         if (err)
 388                 goto out_no_clid;
 389
 390         clnt->cl_procinfo = version->procs;
 391         clnt->cl_maxproc  = version->nrprocs;
 392         clnt->cl_prog     = args->prognumber ? : program->number;
 393         clnt->cl_vers     = version->number;
 394         clnt->cl_stats    = program->stats;
 395         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 396         rpc_init_pipe_dir_head(&clnt->cl_pipedir_objects);
 397         err = -ENOMEM;
 398         if (clnt->cl_metrics == NULL)
 399                 goto out_no_stats;
 400         clnt->cl_program  = program;
 401         INIT_LIST_HEAD(&clnt->cl_tasks);
 402         spin_lock_init(&clnt->cl_lock);
 403
 404         timeout = xprt->timeout;
 405         if (args->timeout != NULL) {
 406                 memcpy(&clnt->cl_timeout_default, args->timeout,
 407                                 sizeof(clnt->cl_timeout_default));
 408                 timeout = &clnt->cl_timeout_default;
 409         }
 410
 411         rpc_clnt_set_transport(clnt, xprt, timeout);
 412
 413         clnt->cl_rtt = &clnt->cl_rtt_default;
 414         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
 415
 416         atomic_set(&clnt->cl_count, 1);
 417
 418         /* save the nodename */
 419         rpc_clnt_set_nodename(clnt, utsname()->nodename);
 420
 421         err = rpc_client_register(clnt, args->authflavor, args->client_name);
 422         if (err)
 423                 goto out_no_path;
 424         if (parent)
 425                 atomic_inc(&parent->cl_count);
 426         return clnt;
 427
 428 out_no_path:
 429         rpc_free_iostats(clnt->cl_metrics);
 430 out_no_stats:
 431         rpc_free_clid(clnt);
 432 out_no_clid:
 433         kfree(clnt);
 434 out_err:
 435         rpciod_down();
 436 out_no_rpciod:
 437         xprt_put(xprt);
 438         return ERR_PTR(err);
 439 }
 440
 441 /**
 442  * rpc_create - create an RPC client and transport with one call
 443  * @args: rpc_clnt create argument structure
 444  *
 445  * Creates and initializes an RPC transport and an RPC client.
 446  *
 447  * It can ping the server in order to determine if it is up, and to see if
 448  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 449  * this behavior so asynchronous tasks can also use rpc_create.
 450  */
 451 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 452 {
 453         struct rpc_xprt *xprt;
 454         struct rpc_clnt *clnt;
 455         struct xprt_create xprtargs = {
 456                 .net = args->net,
 457                 .ident = args->protocol,
 458                 .srcaddr = args->saddress,
 459                 .dstaddr = args->address,
 460                 .addrlen = args->addrsize,
 461                 .servername = args->servername,
 462                 .bc_xprt = args->bc_xprt,
 463         };
 464         char servername[48];
 465
 466         if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
 467                 xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
 468         if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
 469                 xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
 470         /*
 471          * If the caller chooses not to specify a hostname, whip
 472          * up a string representation of the passed-in address.
 473          */
 474         if (xprtargs.servername == NULL) {
 475                 struct sockaddr_un *sun =
 476                                 (struct sockaddr_un *)args->address;
 477                 struct sockaddr_in *sin =
 478                                 (struct sockaddr_in *)args->address;
 479                 struct sockaddr_in6 *sin6 =
 480                                 (struct sockaddr_in6 *)args->address;
 481
 482                 servername[0] = '\0';
 483                 switch (args->address->sa_family) {
 484                 case AF_LOCAL:
 485                         snprintf(servername, sizeof(servername), "%s",
 486                                  sun->sun_path);
 487                         break;
 488                 case AF_INET:
 489                         snprintf(servername, sizeof(servername), "%pI4",
 490                                  &sin->sin_addr.s_addr);
 491                         break;
 492                 case AF_INET6:
 493                         snprintf(servername, sizeof(servername), "%pI6",
 494                                  &sin6->sin6_addr);
 495                         break;
 496                 default:
 497                         /* caller wants default server name, but
 498                          * address family isn't recognized. */
 499                         return ERR_PTR(-EINVAL);
 500                 }
 501                 xprtargs.servername = servername;
 502         }
 503
 504         xprt = xprt_create_transport(&xprtargs);
 505         if (IS_ERR(xprt))
 506                 return (struct rpc_clnt *)xprt;
 507
 508         /*
 509          * By default, kernel RPC client connects from a reserved port.
 510          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 511          * but it is always enabled for rpciod, which handles the connect
 512          * operation.
 513          */
 514         xprt->resvport = 1;
 515         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 516                 xprt->resvport = 0;
 517
 518         clnt = rpc_new_client(args, xprt, NULL);
 519         if (IS_ERR(clnt))
 520                 return clnt;
 521
 522         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 523                 int err = rpc_ping(clnt);
 524                 if (err != 0) {
 525                         rpc_shutdown_client(clnt);
 526                         return ERR_PTR(err);
 527                 }
 528         }
 529
 530         clnt->cl_softrtry = 1;
 531         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 532                 clnt->cl_softrtry = 0;
 533
 534         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 535                 clnt->cl_autobind = 1;
 536         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 537                 clnt->cl_discrtry = 1;
 538         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 539                 clnt->cl_chatty = 1;
 540
 541         return clnt;
 542 }
 543 EXPORT_SYMBOL_GPL(rpc_create);
 544
 545 /*
 546  * This function clones the RPC client structure. It allows us to share the
 547  * same transport while varying parameters such as the authentication
 548  * flavour.
 549  */
 550 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
 551                                            struct rpc_clnt *clnt)
 552 {
 553         struct rpc_xprt *xprt;
 554         struct rpc_clnt *new;
 555         int err;
 556
 557         err = -ENOMEM;
 558         rcu_read_lock();
 559         xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
 560         rcu_read_unlock();
 561         if (xprt == NULL)
 562                 goto out_err;
 563         args->servername = xprt->servername;
 564
 565         new = rpc_new_client(args, xprt, clnt);
 566         if (IS_ERR(new)) {
 567                 err = PTR_ERR(new);
 568                 goto out_err;
 569         }
 570
 571         /* Turn off autobind on clones */
 572         new->cl_autobind = 0;
 573         new->cl_softrtry = clnt->cl_softrtry;
 574         new->cl_discrtry = clnt->cl_discrtry;
 575         new->cl_chatty = clnt->cl_chatty;
 576         return new;
 577
 578 out_err:
 579         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 580         return ERR_PTR(err);
 581 }
 582
 583 /**
 584  * rpc_clone_client - Clone an RPC client structure
 585  *
 586  * @clnt: RPC client whose parameters are copied
 587  *
 588  * Returns a fresh RPC client or an ERR_PTR.
 589  */
 590 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
 591 {
 592         struct rpc_create_args args = {
 593                 .program        = clnt->cl_program,
 594                 .prognumber     = clnt->cl_prog,
 595                 .version        = clnt->cl_vers,
 596                 .authflavor     = clnt->cl_auth->au_flavor,
 597         };
 598         return __rpc_clone_client(&args, clnt);
 599 }
 600 EXPORT_SYMBOL_GPL(rpc_clone_client);
 601
 602 /**
 603  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
 604  *
 605  * @clnt: RPC client whose parameters are copied
 606  * @flavor: security flavor for new client
 607  *
 608  * Returns a fresh RPC client or an ERR_PTR.
 609  */
 610 struct rpc_clnt *
 611 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
 612 {
 613         struct rpc_create_args args = {
 614                 .program        = clnt->cl_program,
 615                 .prognumber     = clnt->cl_prog,
 616                 .version        = clnt->cl_vers,
 617                 .authflavor     = flavor,
 618         };
 619         return __rpc_clone_client(&args, clnt);
 620 }
 621 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
 622
 623 /**
 624  * rpc_switch_client_transport: switch the RPC transport on the fly
 625  * @clnt: pointer to a struct rpc_clnt
 626  * @args: pointer to the new transport arguments
 627  * @timeout: pointer to the new timeout parameters
 628  *
 629  * This function allows the caller to switch the RPC transport for the
 630  * rpc_clnt structure 'clnt' to allow it to connect to a mirrored NFS
 631  * server, for instance.  It assumes that the caller has ensured that
 632  * there are no active RPC tasks by using some form of locking.
 633  *
 634  * Returns zero if "clnt" is now using the new xprt.  Otherwise a
 635  * negative errno is returned, and "clnt" continues to use the old
 636  * xprt.
 637  */
 638 int rpc_switch_client_transport(struct rpc_clnt *clnt,
 639                 struct xprt_create *args,
 640                 const struct rpc_timeout *timeout)
 641 {
 642         const struct rpc_timeout *old_timeo;
 643         rpc_authflavor_t pseudoflavor;
 644         struct rpc_xprt *xprt, *old;
 645         struct rpc_clnt *parent;
 646         int err;
 647
 648         xprt = xprt_create_transport(args);
 649         if (IS_ERR(xprt)) {
 650                 dprintk("RPC:       failed to create new xprt for clnt %p\n",
 651                         clnt);
 652                 return PTR_ERR(xprt);
 653         }
 654
 655         pseudoflavor = clnt->cl_auth->au_flavor;
 656
 657         old_timeo = clnt->cl_timeout;
 658         old = rpc_clnt_set_transport(clnt, xprt, timeout);
 659
 660         rpc_unregister_client(clnt);
 661         __rpc_clnt_remove_pipedir(clnt);
 662
 663         /*
 664          * A new transport was created.  "clnt" therefore
 665          * becomes the root of a new cl_parent tree.  clnt's
 666          * children, if it has any, still point to the old xprt.
 667          */
 668         parent = clnt->cl_parent;
 669         clnt->cl_parent = clnt;
 670
 671         /*
 672          * The old rpc_auth cache cannot be re-used.  GSS
 673          * contexts in particular are between a single
 674          * client and server.
 675          */
 676         err = rpc_client_register(clnt, pseudoflavor, NULL);
 677         if (err)
 678                 goto out_revert;
 679
 680         synchronize_rcu();
 681         if (parent != clnt)
 682                 rpc_release_client(parent);
 683         xprt_put(old);
 684         dprintk("RPC:       replaced xprt for clnt %p\n", clnt);
 685         return 0;
 686
 687 out_revert:
 688         rpc_clnt_set_transport(clnt, old, old_timeo);
 689         clnt->cl_parent = parent;
 690         rpc_client_register(clnt, pseudoflavor, NULL);
 691         xprt_put(xprt);
 692         dprintk("RPC:       failed to switch xprt for clnt %p\n", clnt);
 693         return err;
 694 }
 695 EXPORT_SYMBOL_GPL(rpc_switch_client_transport);
 696
 697 /*
 698  * Kill all tasks for the given client.
 699  * XXX: kill their descendants as well?
 700  */
 701 void rpc_killall_tasks(struct rpc_clnt *clnt)
 702 {
 703         struct rpc_task *rovr;
 704
 705
 706         if (list_empty(&clnt->cl_tasks))
 707                 return;
 708         dprintk("RPC:       killing all tasks for client %p\n", clnt);
 709         /*
 710          * Spin lock all_tasks to prevent changes...
 711          */
 712         spin_lock(&clnt->cl_lock);
 713         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
 714                 if (!RPC_IS_ACTIVATED(rovr))
 715                         continue;
 716                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
 717                         rovr->tk_flags |= RPC_TASK_KILLED;
 718                         rpc_exit(rovr, -EIO);
 719                         if (RPC_IS_QUEUED(rovr))
 720                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
 721                                                         rovr);
 722                 }
 723         }
 724         spin_unlock(&clnt->cl_lock);
 725 }
 726 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
 727
 728 /*
 729  * Properly shut down an RPC client, terminating all outstanding
 730  * requests.
 731  */
 732 void rpc_shutdown_client(struct rpc_clnt *clnt)
 733 {
 734         might_sleep();
 735
 736         dprintk_rcu("RPC:       shutting down %s client for %s\n",
 737                         clnt->cl_program->name,
 738                         rcu_dereference(clnt->cl_xprt)->servername);
 739
 740         while (!list_empty(&clnt->cl_tasks)) {
 741                 rpc_killall_tasks(clnt);
 742                 wait_event_timeout(destroy_wait,
 743                         list_empty(&clnt->cl_tasks), 1*HZ);
 744         }
 745
 746         rpc_release_client(clnt);
 747 }
 748 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 749
 750 /*
 751  * Free an RPC client
 752  */
 753 static struct rpc_clnt *
 754 rpc_free_client(struct rpc_clnt *clnt)
 755 {
 756         struct rpc_clnt *parent = NULL;
 757
 758         dprintk_rcu("RPC:       destroying %s client for %s\n",
 759                         clnt->cl_program->name,
 760                         rcu_dereference(clnt->cl_xprt)->servername);
 761         if (clnt->cl_parent != clnt)
 762                 parent = clnt->cl_parent;
 763         rpc_clnt_remove_pipedir(clnt);
 764         rpc_unregister_client(clnt);
 765         rpc_free_iostats(clnt->cl_metrics);
 766         clnt->cl_metrics = NULL;
 767         xprt_put(rcu_dereference_raw(clnt->cl_xprt));
 768         rpciod_down();
 769         rpc_free_clid(clnt);
 770         kfree(clnt);
 771         return parent;
 772 }
 773
 774 /*
 775  * Free an RPC client
 776  */
 777 static struct rpc_clnt *
 778 rpc_free_auth(struct rpc_clnt *clnt)
 779 {
 780         if (clnt->cl_auth == NULL)
 781                 return rpc_free_client(clnt);
 782
 783         /*
 784          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 785          *       release remaining GSS contexts. This mechanism ensures
 786          *       that it can do so safely.
 787          */
 788         atomic_inc(&clnt->cl_count);
 789         rpcauth_release(clnt->cl_auth);
 790         clnt->cl_auth = NULL;
 791         if (atomic_dec_and_test(&clnt->cl_count))
 792                 return rpc_free_client(clnt);
 793         return NULL;
 794 }
 795
 796 /*
 797  * Release reference to the RPC client
 798  */
 799 void
 800 rpc_release_client(struct rpc_clnt *clnt)
 801 {
 802         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 803
 804         do {
 805                 if (list_empty(&clnt->cl_tasks))
 806                         wake_up(&destroy_wait);
 807                 if (!atomic_dec_and_test(&clnt->cl_count))
 808                         break;
 809                 clnt = rpc_free_auth(clnt);
 810         } while (clnt != NULL);
 811 }
 812 EXPORT_SYMBOL_GPL(rpc_release_client);
 813
 814 /**
 815  * rpc_bind_new_program - bind a new RPC program to an existing client
 816  * @old: old rpc_client
 817  * @program: rpc program to set
 818  * @vers: rpc program version
 819  *
 820  * Clones the rpc client and sets up a new RPC program. This is mainly
 821  * of use for enabling different RPC programs to share the same transport.
 822  * The Sun NFSv2/v3 ACL protocol can do this.
 823  */
 824 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 825                                       const struct rpc_program *program,
 826                                       u32 vers)
 827 {
 828         struct rpc_create_args args = {
 829                 .program        = program,
 830                 .prognumber     = program->number,
 831                 .version        = vers,
 832                 .authflavor     = old->cl_auth->au_flavor,
 833         };
 834         struct rpc_clnt *clnt;
 835         int err;
 836
 837         clnt = __rpc_clone_client(&args, old);
 838         if (IS_ERR(clnt))
 839                 goto out;
 840         err = rpc_ping(clnt);
 841         if (err != 0) {
 842                 rpc_shutdown_client(clnt);
 843                 clnt = ERR_PTR(err);
 844         }
 845 out:
 846         return clnt;
 847 }
 848 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 849
 850 void rpc_task_release_client(struct rpc_task *task)
 851 {
 852         struct rpc_clnt *clnt = task->tk_client;
 853
 854         if (clnt != NULL) {
 855                 /* Remove from client task list */
 856                 spin_lock(&clnt->cl_lock);
 857                 list_del(&task->tk_task);
 858                 spin_unlock(&clnt->cl_lock);
 859                 task->tk_client = NULL;
 860
 861                 rpc_release_client(clnt);
 862         }
 863 }
 864
 865 static
 866 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
 867 {
 868         if (clnt != NULL) {
 869                 rpc_task_release_client(task);
 870                 task->tk_client = clnt;
 871                 atomic_inc(&clnt->cl_count);
 872                 if (clnt->cl_softrtry)
 873                         task->tk_flags |= RPC_TASK_SOFT;
 874                 if (clnt->cl_noretranstimeo)
 875                         task->tk_flags |= RPC_TASK_NO_RETRANS_TIMEOUT;
 876                 if (sk_memalloc_socks()) {
 877                         struct rpc_xprt *xprt;
 878
 879                         rcu_read_lock();
 880                         xprt = rcu_dereference(clnt->cl_xprt);
 881                         if (xprt->swapper)
 882                                 task->tk_flags |= RPC_TASK_SWAPPER;
 883                         rcu_read_unlock();
 884                 }
 885                 /* Add to the client's list of all tasks */
 886                 spin_lock(&clnt->cl_lock);
 887                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
 888                 spin_unlock(&clnt->cl_lock);
 889         }
 890 }
 891
 892 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
 893 {
 894         rpc_task_release_client(task);
 895         rpc_task_set_client(task, clnt);
 896 }
 897 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
 898
 899
 900 static void
 901 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
 902 {
 903         if (msg != NULL) {
 904                 task->tk_msg.rpc_proc = msg->rpc_proc;
 905                 task->tk_msg.rpc_argp = msg->rpc_argp;
 906                 task->tk_msg.rpc_resp = msg->rpc_resp;
 907                 if (msg->rpc_cred != NULL)
 908                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
 909         }
 910 }
 911
 912 /*
 913  * Default callback for async RPC calls
 914  */
 915 static void
 916 rpc_default_callback(struct rpc_task *task, void *data)
 917 {
 918 }
 919
 920 static const struct rpc_call_ops rpc_default_ops = {
 921         .rpc_call_done = rpc_default_callback,
 922 };
 923
 924 /**
 925  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 926  * @task_setup_data: pointer to task initialisation data
 927  */
 928 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 929 {
 930         struct rpc_task *task;
 931
 932         task = rpc_new_task(task_setup_data);
 933         if (IS_ERR(task))
 934                 goto out;
 935
 936         rpc_task_set_client(task, task_setup_data->rpc_client);
 937         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
 938
 939         if (task->tk_action == NULL)
 940                 rpc_call_start(task);
 941
 942         atomic_inc(&task->tk_count);
 943         rpc_execute(task);
 944 out:
 945         return task;
 946 }
 947 EXPORT_SYMBOL_GPL(rpc_run_task);
 948
 949 /**
 950  * rpc_call_sync - Perform a synchronous RPC call
 951  * @clnt: pointer to RPC client
 952  * @msg: RPC call parameters
 953  * @flags: RPC call flags
 954  */
 955 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 956 {
 957         struct rpc_task *task;
 958         struct rpc_task_setup task_setup_data = {
 959                 .rpc_client = clnt,
 960                 .rpc_message = msg,
 961                 .callback_ops = &rpc_default_ops,
 962                 .flags = flags,
 963         };
 964         int status;
 965
 966         WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
 967         if (flags & RPC_TASK_ASYNC) {
 968                 rpc_release_calldata(task_setup_data.callback_ops,
 969                         task_setup_data.callback_data);
 970                 return -EINVAL;
 971         }
 972
 973         task = rpc_run_task(&task_setup_data);
 974         if (IS_ERR(task))
 975                 return PTR_ERR(task);
 976         status = task->tk_status;
 977         rpc_put_task(task);
 978         return status;
 979 }
 980 EXPORT_SYMBOL_GPL(rpc_call_sync);
 981
 982 /**
 983  * rpc_call_async - Perform an asynchronous RPC call
 984  * @clnt: pointer to RPC client
 985  * @msg: RPC call parameters
 986  * @flags: RPC call flags
 987  * @tk_ops: RPC call ops
 988  * @data: user call data
 989  */
 990 int
 991 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
 992                const struct rpc_call_ops *tk_ops, void *data)
 993 {
 994         struct rpc_task *task;
 995         struct rpc_task_setup task_setup_data = {
 996                 .rpc_client = clnt,
 997                 .rpc_message = msg,
 998                 .callback_ops = tk_ops,
 999                 .callback_data = data,
1000                 .flags = flags|RPC_TASK_ASYNC,
1001         };
1002
1003         task = rpc_run_task(&task_setup_data);
1004         if (IS_ERR(task))
1005                 return PTR_ERR(task);
1006         rpc_put_task(task);
1007         return 0;
1008 }
1009 EXPORT_SYMBOL_GPL(rpc_call_async);
1010
1011 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1012 /**
1013  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
1014  * rpc_execute against it
1015  * @req: RPC request
1016  * @tk_ops: RPC call ops
1017  */
1018 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
1019                                 const struct rpc_call_ops *tk_ops)
1020 {
1021         struct rpc_task *task;
1022         struct xdr_buf *xbufp = &req->rq_snd_buf;
1023         struct rpc_task_setup task_setup_data = {
1024                 .callback_ops = tk_ops,
1025         };
1026
1027         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
1028         /*
1029          * Create an rpc_task to send the data
1030          */
1031         task = rpc_new_task(&task_setup_data);
1032         if (IS_ERR(task)) {
1033                 xprt_free_bc_request(req);
1034                 goto out;
1035         }
1036         task->tk_rqstp = req;
1037
1038         /*
1039          * Set up the xdr_buf length.
1040          * This also indicates that the buffer is XDR encoded already.
1041          */
1042         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
1043                         xbufp->tail[0].iov_len;
1044
1045         task->tk_action = call_bc_transmit;
1046         atomic_inc(&task->tk_count);
1047         WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
1048         rpc_execute(task);
1049
1050 out:
1051         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
1052         return task;
1053 }
1054 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1055
1056 void
1057 rpc_call_start(struct rpc_task *task)
1058 {
1059         task->tk_action = call_start;
1060 }
1061 EXPORT_SYMBOL_GPL(rpc_call_start);
1062
1063 /**
1064  * rpc_peeraddr - extract remote peer address from clnt's xprt
1065  * @clnt: RPC client structure
1066  * @buf: target buffer
1067  * @bufsize: length of target buffer
1068  *
1069  * Returns the number of bytes that are actually in the stored address.
1070  */
1071 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
1072 {
1073         size_t bytes;
1074         struct rpc_xprt *xprt;
1075
1076         rcu_read_lock();
1077         xprt = rcu_dereference(clnt->cl_xprt);
1078
1079         bytes = xprt->addrlen;
1080         if (bytes > bufsize)
1081                 bytes = bufsize;
1082         memcpy(buf, &xprt->addr, bytes);
1083         rcu_read_unlock();
1084
1085         return bytes;
1086 }
1087 EXPORT_SYMBOL_GPL(rpc_peeraddr);
1088
1089 /**
1090  * rpc_peeraddr2str - return remote peer address in printable format
1091  * @clnt: RPC client structure
1092  * @format: address format
1093  *
1094  * NB: the lifetime of the memory referenced by the returned pointer is
1095  * the same as the rpc_xprt itself.  As long as the caller uses this
1096  * pointer, it must hold the RCU read lock.
1097  */
1098 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
1099                              enum rpc_display_format_t format)
1100 {
1101         struct rpc_xprt *xprt;
1102
1103         xprt = rcu_dereference(clnt->cl_xprt);
1104
1105         if (xprt->address_strings[format] != NULL)
1106                 return xprt->address_strings[format];
1107         else
1108                 return "unprintable";
1109 }
1110 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
1111
1112 static const struct sockaddr_in rpc_inaddr_loopback = {
1113         .sin_family             = AF_INET,
1114         .sin_addr.s_addr        = htonl(INADDR_ANY),
1115 };
1116
1117 static const struct sockaddr_in6 rpc_in6addr_loopback = {
1118         .sin6_family            = AF_INET6,
1119         .sin6_addr              = IN6ADDR_ANY_INIT,
1120 };
1121
1122 /*
1123  * Try a getsockname() on a connected datagram socket.  Using a
1124  * connected datagram socket prevents leaving a socket in TIME_WAIT.
1125  * This conserves the ephemeral port number space.
1126  *
1127  * Returns zero and fills in "buf" if successful; otherwise, a
1128  * negative errno is returned.
1129  */
1130 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1131                         struct sockaddr *buf, int buflen)
1132 {
1133         struct socket *sock;
1134         int err;
1135
1136         err = __sock_create(net, sap->sa_family,
1137                                 SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1138         if (err < 0) {
1139                 dprintk("RPC:       can't create UDP socket (%d)\n", err);
1140                 goto out;
1141         }
1142
1143         switch (sap->sa_family) {
1144         case AF_INET:
1145                 err = kernel_bind(sock,
1146                                 (struct sockaddr *)&rpc_inaddr_loopback,
1147                                 sizeof(rpc_inaddr_loopback));
1148                 break;
1149         case AF_INET6:
1150                 err = kernel_bind(sock,
1151                                 (struct sockaddr *)&rpc_in6addr_loopback,
1152                                 sizeof(rpc_in6addr_loopback));
1153                 break;
1154         default:
1155                 err = -EAFNOSUPPORT;
1156                 goto out;
1157         }
1158         if (err < 0) {
1159                 dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1160                 goto out_release;
1161         }
1162
1163         err = kernel_connect(sock, sap, salen, 0);
1164         if (err < 0) {
1165                 dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1166                 goto out_release;
1167         }
1168
1169         err = kernel_getsockname(sock, buf, &buflen);
1170         if (err < 0) {
1171                 dprintk("RPC:       getsockname failed (%d)\n", err);
1172                 goto out_release;
1173         }
1174
1175         err = 0;
1176         if (buf->sa_family == AF_INET6) {
1177                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1178                 sin6->sin6_scope_id = 0;
1179         }
1180         dprintk("RPC:       %s succeeded\n", __func__);
1181
1182 out_release:
1183         sock_release(sock);
1184 out:
1185         return err;
1186 }
1187
1188 /*
1189  * Scraping a connected socket failed, so we don't have a useable
1190  * local address.  Fallback: generate an address that will prevent
1191  * the server from calling us back.
1192  *
1193  * Returns zero and fills in "buf" if successful; otherwise, a
1194  * negative errno is returned.
1195  */
1196 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1197 {
1198         switch (family) {
1199         case AF_INET:
1200                 if (buflen < sizeof(rpc_inaddr_loopback))
1201                         return -EINVAL;
1202                 memcpy(buf, &rpc_inaddr_loopback,
1203                                 sizeof(rpc_inaddr_loopback));
1204                 break;
1205         case AF_INET6:
1206                 if (buflen < sizeof(rpc_in6addr_loopback))
1207                         return -EINVAL;
1208                 memcpy(buf, &rpc_in6addr_loopback,
1209                                 sizeof(rpc_in6addr_loopback));
1210         default:
1211                 dprintk("RPC:       %s: address family not supported\n",
1212                         __func__);
1213                 return -EAFNOSUPPORT;
1214         }
1215         dprintk("RPC:       %s: succeeded\n", __func__);
1216         return 0;
1217 }
1218
1219 /**
1220  * rpc_localaddr - discover local endpoint address for an RPC client
1221  * @clnt: RPC client structure
1222  * @buf: target buffer
1223  * @buflen: size of target buffer, in bytes
1224  *
1225  * Returns zero and fills in "buf" and "buflen" if successful;
1226  * otherwise, a negative errno is returned.
1227  *
1228  * This works even if the underlying transport is not currently connected,
1229  * or if the upper layer never previously provided a source address.
1230  *
1231  * The result of this function call is transient: multiple calls in
1232  * succession may give different results, depending on how local
1233  * networking configuration changes over time.
1234  */
1235 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1236 {
1237         struct sockaddr_storage address;
1238         struct sockaddr *sap = (struct sockaddr *)&address;
1239         struct rpc_xprt *xprt;
1240         struct net *net;
1241         size_t salen;
1242         int err;
1243
1244         rcu_read_lock();
1245         xprt = rcu_dereference(clnt->cl_xprt);
1246         salen = xprt->addrlen;
1247         memcpy(sap, &xprt->addr, salen);
1248         net = get_net(xprt->xprt_net);
1249         rcu_read_unlock();
1250
1251         rpc_set_port(sap, 0);
1252         err = rpc_sockname(net, sap, salen, buf, buflen);
1253         put_net(net);
1254         if (err != 0)
1255                 /* Couldn't discover local address, return ANYADDR */
1256                 return rpc_anyaddr(sap->sa_family, buf, buflen);
1257         return 0;
1258 }
1259 EXPORT_SYMBOL_GPL(rpc_localaddr);
1260
1261 void
1262 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1263 {
1264         struct rpc_xprt *xprt;
1265
1266         rcu_read_lock();
1267         xprt = rcu_dereference(clnt->cl_xprt);
1268         if (xprt->ops->set_buffer_size)
1269                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1270         rcu_read_unlock();
1271 }
1272 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1273
1274 /**
1275  * rpc_protocol - Get transport protocol number for an RPC client
1276  * @clnt: RPC client to query
1277  *
1278  */
1279 int rpc_protocol(struct rpc_clnt *clnt)
1280 {
1281         int protocol;
1282
1283         rcu_read_lock();
1284         protocol = rcu_dereference(clnt->cl_xprt)->prot;
1285         rcu_read_unlock();
1286         return protocol;
1287 }
1288 EXPORT_SYMBOL_GPL(rpc_protocol);
1289
1290 /**
1291  * rpc_net_ns - Get the network namespace for this RPC client
1292  * @clnt: RPC client to query
1293  *
1294  */
1295 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1296 {
1297         struct net *ret;
1298
1299         rcu_read_lock();
1300         ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1301         rcu_read_unlock();
1302         return ret;
1303 }
1304 EXPORT_SYMBOL_GPL(rpc_net_ns);
1305
1306 /**
1307  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1308  * @clnt: RPC client to query
1309  *
1310  * For stream transports, this is one RPC record fragment (see RFC
1311  * 1831), as we don't support multi-record requests yet.  For datagram
1312  * transports, this is the size of an IP packet minus the IP, UDP, and
1313  * RPC header sizes.
1314  */
1315 size_t rpc_max_payload(struct rpc_clnt *clnt)
1316 {
1317         size_t ret;
1318
1319         rcu_read_lock();
1320         ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1321         rcu_read_unlock();
1322         return ret;
1323 }
1324 EXPORT_SYMBOL_GPL(rpc_max_payload);
1325
1326 /**
1327  * rpc_get_timeout - Get timeout for transport in units of HZ
1328  * @clnt: RPC client to query
1329  */
1330 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1331 {
1332         unsigned long ret;
1333
1334         rcu_read_lock();
1335         ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1336         rcu_read_unlock();
1337         return ret;
1338 }
1339 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1340
1341 /**
1342  * rpc_force_rebind - force transport to check that remote port is unchanged
1343  * @clnt: client to rebind
1344  *
1345  */
1346 void rpc_force_rebind(struct rpc_clnt *clnt)
1347 {
1348         if (clnt->cl_autobind) {
1349                 rcu_read_lock();
1350                 xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1351                 rcu_read_unlock();
1352         }
1353 }
1354 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1355
1356 /*
1357  * Restart an (async) RPC call from the call_prepare state.
1358  * Usually called from within the exit handler.
1359  */
1360 int
1361 rpc_restart_call_prepare(struct rpc_task *task)
1362 {
1363         if (RPC_ASSASSINATED(task))
1364                 return 0;
1365         task->tk_action = call_start;
1366         if (task->tk_ops->rpc_call_prepare != NULL)
1367                 task->tk_action = rpc_prepare_task;
1368         return 1;
1369 }
1370 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1371
1372 /*
1373  * Restart an (async) RPC call. Usually called from within the
1374  * exit handler.
1375  */
1376 int
1377 rpc_restart_call(struct rpc_task *task)
1378 {
1379         if (RPC_ASSASSINATED(task))
1380                 return 0;
1381         task->tk_action = call_start;
1382         return 1;
1383 }
1384 EXPORT_SYMBOL_GPL(rpc_restart_call);
1385
1386 #ifdef RPC_DEBUG
1387 static const char *rpc_proc_name(const struct rpc_task *task)
1388 {
1389         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1390
1391         if (proc) {
1392                 if (proc->p_name)
1393                         return proc->p_name;
1394                 else
1395                         return "NULL";
1396         } else
1397                 return "no proc";
1398 }
1399 #endif
1400
1401 /*
1402  * 0.  Initial state
1403  *
1404  *     Other FSM states can be visited zero or more times, but
1405  *     this state is visited exactly once for each RPC.
1406  */
1407 static void
1408 call_start(struct rpc_task *task)
1409 {
1410         struct rpc_clnt *clnt = task->tk_client;
1411
1412         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1413                         clnt->cl_program->name, clnt->cl_vers,
1414                         rpc_proc_name(task),
1415                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
1416
1417         /* Increment call count */
1418         task->tk_msg.rpc_proc->p_count++;
1419         clnt->cl_stats->rpccnt++;
1420         task->tk_action = call_reserve;
1421 }
1422
1423 /*
1424  * 1.   Reserve an RPC call slot
1425  */
1426 static void
1427 call_reserve(struct rpc_task *task)
1428 {
1429         dprint_status(task);
1430
1431         task->tk_status  = 0;
1432         task->tk_action  = call_reserveresult;
1433         xprt_reserve(task);
1434 }
1435
1436 static void call_retry_reserve(struct rpc_task *task);
1437
1438 /*
1439  * 1b.  Grok the result of xprt_reserve()
1440  */
1441 static void
1442 call_reserveresult(struct rpc_task *task)
1443 {
1444         int status = task->tk_status;
1445
1446         dprint_status(task);
1447
1448         /*
1449          * After a call to xprt_reserve(), we must have either
1450          * a request slot or else an error status.
1451          */
1452         task->tk_status = 0;
1453         if (status >= 0) {
1454                 if (task->tk_rqstp) {
1455                         task->tk_action = call_refresh;
1456                         return;
1457                 }
1458
1459                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1460                                 __func__, status);
1461                 rpc_exit(task, -EIO);
1462                 return;
1463         }
1464
1465         /*
1466          * Even though there was an error, we may have acquired
1467          * a request slot somehow.  Make sure not to leak it.
1468          */
1469         if (task->tk_rqstp) {
1470                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1471                                 __func__, status);
1472                 xprt_release(task);
1473         }
1474
1475         switch (status) {
1476         case -ENOMEM:
1477                 rpc_delay(task, HZ >> 2);
1478         case -EAGAIN:   /* woken up; retry */
1479                 task->tk_action = call_retry_reserve;
1480                 return;
1481         case -EIO:      /* probably a shutdown */
1482                 break;
1483         default:
1484                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1485                                 __func__, status);
1486                 break;
1487         }
1488         rpc_exit(task, status);
1489 }
1490
1491 /*
1492  * 1c.  Retry reserving an RPC call slot
1493  */
1494 static void
1495 call_retry_reserve(struct rpc_task *task)
1496 {
1497         dprint_status(task);
1498
1499         task->tk_status  = 0;
1500         task->tk_action  = call_reserveresult;
1501         xprt_retry_reserve(task);
1502 }
1503
1504 /*
1505  * 2.   Bind and/or refresh the credentials
1506  */
1507 static void
1508 call_refresh(struct rpc_task *task)
1509 {
1510         dprint_status(task);
1511
1512         task->tk_action = call_refreshresult;
1513         task->tk_status = 0;
1514         task->tk_client->cl_stats->rpcauthrefresh++;
1515         rpcauth_refreshcred(task);
1516 }
1517
1518 /*
1519  * 2a.  Process the results of a credential refresh
1520  */
1521 static void
1522 call_refreshresult(struct rpc_task *task)
1523 {
1524         int status = task->tk_status;
1525
1526         dprint_status(task);
1527
1528         task->tk_status = 0;
1529         task->tk_action = call_refresh;
1530         switch (status) {
1531         case 0:
1532                 if (rpcauth_uptodatecred(task)) {
1533                         task->tk_action = call_allocate;
1534                         return;
1535                 }
1536                 /* Use rate-limiting and a max number of retries if refresh
1537                  * had status 0 but failed to update the cred.
1538                  */
1539         case -ETIMEDOUT:
1540                 rpc_delay(task, 3*HZ);
1541         case -EAGAIN:
1542                 status = -EACCES;
1543         case -EKEYEXPIRED:
1544                 if (!task->tk_cred_retry)
1545                         break;
1546                 task->tk_cred_retry--;
1547                 dprintk("RPC: %5u %s: retry refresh creds\n",
1548                                 task->tk_pid, __func__);
1549                 return;
1550         }
1551         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1552                                 task->tk_pid, __func__, status);
1553         rpc_exit(task, status);
1554 }
1555
1556 /*
1557  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1558  *      (Note: buffer memory is freed in xprt_release).
1559  */
1560 static void
1561 call_allocate(struct rpc_task *task)
1562 {
1563         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1564         struct rpc_rqst *req = task->tk_rqstp;
1565         struct rpc_xprt *xprt = req->rq_xprt;
1566         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1567
1568         dprint_status(task);
1569
1570         task->tk_status = 0;
1571         task->tk_action = call_bind;
1572
1573         if (req->rq_buffer)
1574                 return;
1575
1576         if (proc->p_proc != 0) {
1577                 BUG_ON(proc->p_arglen == 0);
1578                 if (proc->p_decode != NULL)
1579                         BUG_ON(proc->p_replen == 0);
1580         }
1581
1582         /*
1583          * Calculate the size (in quads) of the RPC call
1584          * and reply headers, and convert both values
1585          * to byte sizes.
1586          */
1587         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1588         req->rq_callsize <<= 2;
1589         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1590         req->rq_rcvsize <<= 2;
1591
1592         req->rq_buffer = xprt->ops->buf_alloc(task,
1593                                         req->rq_callsize + req->rq_rcvsize);
1594         if (req->rq_buffer != NULL)
1595                 return;
1596
1597         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1598
1599         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1600                 task->tk_action = call_allocate;
1601                 rpc_delay(task, HZ>>4);
1602                 return;
1603         }
1604
1605         rpc_exit(task, -ERESTARTSYS);
1606 }
1607
1608 static inline int
1609 rpc_task_need_encode(struct rpc_task *task)
1610 {
1611         return task->tk_rqstp->rq_snd_buf.len == 0;
1612 }
1613
1614 static inline void
1615 rpc_task_force_reencode(struct rpc_task *task)
1616 {
1617         task->tk_rqstp->rq_snd_buf.len = 0;
1618         task->tk_rqstp->rq_bytes_sent = 0;
1619 }
1620
1621 static inline void
1622 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1623 {
1624         buf->head[0].iov_base = start;
1625         buf->head[0].iov_len = len;
1626         buf->tail[0].iov_len = 0;
1627         buf->page_len = 0;
1628         buf->flags = 0;
1629         buf->len = 0;
1630         buf->buflen = len;
1631 }
1632
1633 /*
1634  * 3.   Encode arguments of an RPC call
1635  */
1636 static void
1637 rpc_xdr_encode(struct rpc_task *task)
1638 {
1639         struct rpc_rqst *req = task->tk_rqstp;
1640         kxdreproc_t     encode;
1641         __be32          *p;
1642
1643         dprint_status(task);
1644
1645         rpc_xdr_buf_init(&req->rq_snd_buf,
1646                          req->rq_buffer,
1647                          req->rq_callsize);
1648         rpc_xdr_buf_init(&req->rq_rcv_buf,
1649                          (char *)req->rq_buffer + req->rq_callsize,
1650                          req->rq_rcvsize);
1651
1652         p = rpc_encode_header(task);
1653         if (p == NULL) {
1654                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1655                 rpc_exit(task, -EIO);
1656                 return;
1657         }
1658
1659         encode = task->tk_msg.rpc_proc->p_encode;
1660         if (encode == NULL)
1661                 return;
1662
1663         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1664                         task->tk_msg.rpc_argp);
1665 }
1666
1667 /*
1668  * 4.   Get the server port number if not yet set
1669  */
1670 static void
1671 call_bind(struct rpc_task *task)
1672 {
1673         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1674
1675         dprint_status(task);
1676
1677         task->tk_action = call_connect;
1678         if (!xprt_bound(xprt)) {
1679                 task->tk_action = call_bind_status;
1680                 task->tk_timeout = xprt->bind_timeout;
1681                 xprt->ops->rpcbind(task);
1682         }
1683 }
1684
1685 /*
1686  * 4a.  Sort out bind result
1687  */
1688 static void
1689 call_bind_status(struct rpc_task *task)
1690 {
1691         int status = -EIO;
1692
1693         if (task->tk_status >= 0) {
1694                 dprint_status(task);
1695                 task->tk_status = 0;
1696                 task->tk_action = call_connect;
1697                 return;
1698         }
1699
1700         trace_rpc_bind_status(task);
1701         switch (task->tk_status) {
1702         case -ENOMEM:
1703                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1704                 rpc_delay(task, HZ >> 2);
1705                 goto retry_timeout;
1706         case -EACCES:
1707                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1708                                 "unavailable\n", task->tk_pid);
1709                 /* fail immediately if this is an RPC ping */
1710                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1711                         status = -EOPNOTSUPP;
1712                         break;
1713                 }
1714                 if (task->tk_rebind_retry == 0)
1715                         break;
1716                 task->tk_rebind_retry--;
1717                 rpc_delay(task, 3*HZ);
1718                 goto retry_timeout;
1719         case -ETIMEDOUT:
1720                 dprintk("RPC: %5u rpcbind request timed out\n",
1721                                 task->tk_pid);
1722                 goto retry_timeout;
1723         case -EPFNOSUPPORT:
1724                 /* server doesn't support any rpcbind version we know of */
1725                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1726                                 task->tk_pid);
1727                 break;
1728         case -EPROTONOSUPPORT:
1729                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1730                                 task->tk_pid);
1731                 task->tk_status = 0;
1732                 task->tk_action = call_bind;
1733                 return;
1734         case -ECONNREFUSED:             /* connection problems */
1735         case -ECONNRESET:
1736         case -ECONNABORTED:
1737         case -ENOTCONN:
1738         case -EHOSTDOWN:
1739         case -EHOSTUNREACH:
1740         case -ENETUNREACH:
1741         case -EPIPE:
1742                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1743                                 task->tk_pid, task->tk_status);
1744                 if (!RPC_IS_SOFTCONN(task)) {
1745                         rpc_delay(task, 5*HZ);
1746                         goto retry_timeout;
1747                 }
1748                 status = task->tk_status;
1749                 break;
1750         default:
1751                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1752                                 task->tk_pid, -task->tk_status);
1753         }
1754
1755         rpc_exit(task, status);
1756         return;
1757
1758 retry_timeout:
1759         task->tk_action = call_timeout;
1760 }
1761
1762 /*
1763  * 4b.  Connect to the RPC server
1764  */
1765 static void
1766 call_connect(struct rpc_task *task)
1767 {
1768         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1769
1770         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1771                         task->tk_pid, xprt,
1772                         (xprt_connected(xprt) ? "is" : "is not"));
1773
1774         task->tk_action = call_transmit;
1775         if (!xprt_connected(xprt)) {
1776                 task->tk_action = call_connect_status;
1777                 if (task->tk_status < 0)
1778                         return;
1779                 if (task->tk_flags & RPC_TASK_NOCONNECT) {
1780                         rpc_exit(task, -ENOTCONN);
1781                         return;
1782                 }
1783                 xprt_connect(task);
1784         }
1785 }
1786
1787 /*
1788  * 4c.  Sort out connect result
1789  */
1790 static void
1791 call_connect_status(struct rpc_task *task)
1792 {
1793         struct rpc_clnt *clnt = task->tk_client;
1794         int status = task->tk_status;
1795
1796         dprint_status(task);
1797
1798         trace_rpc_connect_status(task, status);
1799         task->tk_status = 0;
1800         switch (status) {
1801         case -ECONNREFUSED:
1802         case -ECONNRESET:
1803         case -ECONNABORTED:
1804         case -ENETUNREACH:
1805         case -EHOSTUNREACH:
1806                 if (RPC_IS_SOFTCONN(task))
1807                         break;
1808                 /* retry with existing socket, after a delay */
1809                 rpc_delay(task, 3*HZ);
1810         case -EAGAIN:
1811                 /* Check for timeouts before looping back to call_bind */
1812         case -ETIMEDOUT:
1813                 task->tk_action = call_timeout;
1814                 return;
1815         case 0:
1816                 clnt->cl_stats->netreconn++;
1817                 task->tk_action = call_transmit;
1818                 return;
1819         }
1820         rpc_exit(task, status);
1821 }
1822
1823 /*
1824  * 5.   Transmit the RPC request, and wait for reply
1825  */
1826 static void
1827 call_transmit(struct rpc_task *task)
1828 {
1829         int is_retrans = RPC_WAS_SENT(task);
1830
1831         dprint_status(task);
1832
1833         task->tk_action = call_status;
1834         if (task->tk_status < 0)
1835                 return;
1836         if (!xprt_prepare_transmit(task))
1837                 return;
1838         task->tk_action = call_transmit_status;
1839         /* Encode here so that rpcsec_gss can use correct sequence number. */
1840         if (rpc_task_need_encode(task)) {
1841                 rpc_xdr_encode(task);
1842                 /* Did the encode result in an error condition? */
1843                 if (task->tk_status != 0) {
1844                         /* Was the error nonfatal? */
1845                         if (task->tk_status == -EAGAIN)
1846                                 rpc_delay(task, HZ >> 4);
1847                         else
1848                                 rpc_exit(task, task->tk_status);
1849                         return;
1850                 }
1851         }
1852         xprt_transmit(task);
1853         if (task->tk_status < 0)
1854                 return;
1855         if (is_retrans)
1856                 task->tk_client->cl_stats->rpcretrans++;
1857         /*
1858          * On success, ensure that we call xprt_end_transmit() before sleeping
1859          * in order to allow access to the socket to other RPC requests.
1860          */
1861         call_transmit_status(task);
1862         if (rpc_reply_expected(task))
1863                 return;
1864         task->tk_action = rpc_exit_task;
1865         rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1866 }
1867
1868 /*
1869  * 5a.  Handle cleanup after a transmission
1870  */
1871 static void
1872 call_transmit_status(struct rpc_task *task)
1873 {
1874         task->tk_action = call_status;
1875
1876         /*
1877          * Common case: success.  Force the compiler to put this
1878          * test first.
1879          */
1880         if (task->tk_status == 0) {
1881                 xprt_end_transmit(task);
1882                 rpc_task_force_reencode(task);
1883                 return;
1884         }
1885
1886         switch (task->tk_status) {
1887         case -EAGAIN:
1888                 break;
1889         default:
1890                 dprint_status(task);
1891                 xprt_end_transmit(task);
1892                 rpc_task_force_reencode(task);
1893                 break;
1894                 /*
1895                  * Special cases: if we've been waiting on the
1896                  * socket's write_space() callback, or if the
1897                  * socket just returned a connection error,
1898                  * then hold onto the transport lock.
1899                  */
1900         case -ECONNREFUSED:
1901         case -EHOSTDOWN:
1902         case -EHOSTUNREACH:
1903         case -ENETUNREACH:
1904                 if (RPC_IS_SOFTCONN(task)) {
1905                         xprt_end_transmit(task);
1906                         rpc_exit(task, task->tk_status);
1907                         break;
1908                 }
1909         case -ECONNRESET:
1910         case -ECONNABORTED:
1911         case -ENOTCONN:
1912         case -EPIPE:
1913                 rpc_task_force_reencode(task);
1914         }
1915 }
1916
1917 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1918 /*
1919  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1920  * addition, disconnect on connectivity errors.
1921  */
1922 static void
1923 call_bc_transmit(struct rpc_task *task)
1924 {
1925         struct rpc_rqst *req = task->tk_rqstp;
1926
1927         if (!xprt_prepare_transmit(task)) {
1928                 /*
1929                  * Could not reserve the transport. Try again after the
1930                  * transport is released.
1931                  */
1932                 task->tk_status = 0;
1933                 task->tk_action = call_bc_transmit;
1934                 return;
1935         }
1936
1937         task->tk_action = rpc_exit_task;
1938         if (task->tk_status < 0) {
1939                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1940                         "error: %d\n", task->tk_status);
1941                 return;
1942         }
1943
1944         xprt_transmit(task);
1945         xprt_end_transmit(task);
1946         dprint_status(task);
1947         switch (task->tk_status) {
1948         case 0:
1949                 /* Success */
1950                 break;
1951         case -EHOSTDOWN:
1952         case -EHOSTUNREACH:
1953         case -ENETUNREACH:
1954         case -ETIMEDOUT:
1955                 /*
1956                  * Problem reaching the server.  Disconnect and let the
1957                  * forechannel reestablish the connection.  The server will
1958                  * have to retransmit the backchannel request and we'll
1959                  * reprocess it.  Since these ops are idempotent, there's no
1960                  * need to cache our reply at this time.
1961                  */
1962                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1963                         "error: %d\n", task->tk_status);
1964                 xprt_conditional_disconnect(req->rq_xprt,
1965                         req->rq_connect_cookie);
1966                 break;
1967         default:
1968                 /*
1969                  * We were unable to reply and will have to drop the
1970                  * request.  The server should reconnect and retransmit.
1971                  */
1972                 WARN_ON_ONCE(task->tk_status == -EAGAIN);
1973                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1974                         "error: %d\n", task->tk_status);
1975                 break;
1976         }
1977         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1978 }
1979 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1980
1981 /*
1982  * 6.   Sort out the RPC call status
1983  */
1984 static void
1985 call_status(struct rpc_task *task)
1986 {
1987         struct rpc_clnt *clnt = task->tk_client;
1988         struct rpc_rqst *req = task->tk_rqstp;
1989         int             status;
1990
1991         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
1992                 task->tk_status = req->rq_reply_bytes_recvd;
1993
1994         dprint_status(task);
1995
1996         status = task->tk_status;
1997         if (status >= 0) {
1998                 task->tk_action = call_decode;
1999                 return;
2000         }
2001
2002         trace_rpc_call_status(task);
2003         task->tk_status = 0;
2004         switch(status) {
2005         case -EHOSTDOWN:
2006         case -EHOSTUNREACH:
2007         case -ENETUNREACH:
2008                 /*
2009                  * Delay any retries for 3 seconds, then handle as if it
2010                  * were a timeout.
2011                  */
2012                 rpc_delay(task, 3*HZ);
2013         case -ETIMEDOUT:
2014                 task->tk_action = call_timeout;
2015                 if (!(task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT)
2016                     && task->tk_client->cl_discrtry)
2017                         xprt_conditional_disconnect(req->rq_xprt,
2018                                         req->rq_connect_cookie);
2019                 break;
2020         case -ECONNREFUSED:
2021         case -ECONNRESET:
2022         case -ECONNABORTED:
2023                 rpc_force_rebind(clnt);
2024                 rpc_delay(task, 3*HZ);
2025         case -EPIPE:
2026         case -ENOTCONN:
2027                 task->tk_action = call_bind;
2028                 break;
2029         case -EAGAIN:
2030                 task->tk_action = call_transmit;
2031                 break;
2032         case -EIO:
2033                 /* shutdown or soft timeout */
2034                 rpc_exit(task, status);
2035                 break;
2036         default:
2037                 if (clnt->cl_chatty)
2038                         printk("%s: RPC call returned error %d\n",
2039                                clnt->cl_program->name, -status);
2040                 rpc_exit(task, status);
2041         }
2042 }
2043
2044 /*
2045  * 6a.  Handle RPC timeout
2046  *      We do not release the request slot, so we keep using the
2047  *      same XID for all retransmits.
2048  */
2049 static void
2050 call_timeout(struct rpc_task *task)
2051 {
2052         struct rpc_clnt *clnt = task->tk_client;
2053
2054         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
2055                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
2056                 goto retry;
2057         }
2058
2059         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
2060         task->tk_timeouts++;
2061
2062         if (RPC_IS_SOFTCONN(task)) {
2063                 rpc_exit(task, -ETIMEDOUT);
2064                 return;
2065         }
2066         if (RPC_IS_SOFT(task)) {
2067                 if (clnt->cl_chatty) {
2068                         rcu_read_lock();
2069                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
2070                                 clnt->cl_program->name,
2071                                 rcu_dereference(clnt->cl_xprt)->servername);
2072                         rcu_read_unlock();
2073                 }
2074                 if (task->tk_flags & RPC_TASK_TIMEOUT)
2075                         rpc_exit(task, -ETIMEDOUT);
2076                 else
2077                         rpc_exit(task, -EIO);
2078                 return;
2079         }
2080
2081         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
2082                 task->tk_flags |= RPC_CALL_MAJORSEEN;
2083                 if (clnt->cl_chatty) {
2084                         rcu_read_lock();
2085                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
2086                         clnt->cl_program->name,
2087                         rcu_dereference(clnt->cl_xprt)->servername);
2088                         rcu_read_unlock();
2089                 }
2090         }
2091         rpc_force_rebind(clnt);
2092         /*
2093          * Did our request time out due to an RPCSEC_GSS out-of-sequence
2094          * event? RFC2203 requires the server to drop all such requests.
2095          */
2096         rpcauth_invalcred(task);
2097
2098 retry:
2099         task->tk_action = call_bind;
2100         task->tk_status = 0;
2101 }
2102
2103 /*
2104  * 7.   Decode the RPC reply
2105  */
2106 static void
2107 call_decode(struct rpc_task *task)
2108 {
2109         struct rpc_clnt *clnt = task->tk_client;
2110         struct rpc_rqst *req = task->tk_rqstp;
2111         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
2112         __be32          *p;
2113
2114         dprint_status(task);
2115
2116         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
2117                 if (clnt->cl_chatty) {
2118                         rcu_read_lock();
2119                         printk(KERN_NOTICE "%s: server %s OK\n",
2120                                 clnt->cl_program->name,
2121                                 rcu_dereference(clnt->cl_xprt)->servername);
2122                         rcu_read_unlock();
2123                 }
2124                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
2125         }
2126
2127         /*
2128          * Ensure that we see all writes made by xprt_complete_rqst()
2129          * before it changed req->rq_reply_bytes_recvd.
2130          */
2131         smp_rmb();
2132         req->rq_rcv_buf.len = req->rq_private_buf.len;
2133
2134         /* Check that the softirq receive buffer is valid */
2135         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
2136                                 sizeof(req->rq_rcv_buf)) != 0);
2137
2138         if (req->rq_rcv_buf.len < 12) {
2139                 if (!RPC_IS_SOFT(task)) {
2140                         task->tk_action = call_bind;
2141                         goto out_retry;
2142                 }
2143                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2144                                 clnt->cl_program->name, task->tk_status);
2145                 task->tk_action = call_timeout;
2146                 goto out_retry;
2147         }
2148
2149         p = rpc_verify_header(task);
2150         if (IS_ERR(p)) {
2151                 if (p == ERR_PTR(-EAGAIN))
2152                         goto out_retry;
2153                 return;
2154         }
2155
2156         task->tk_action = rpc_exit_task;
2157
2158         if (decode) {
2159                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2160                                                       task->tk_msg.rpc_resp);
2161         }
2162         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2163                         task->tk_status);
2164         return;
2165 out_retry:
2166         task->tk_status = 0;
2167         /* Note: rpc_verify_header() may have freed the RPC slot */
2168         if (task->tk_rqstp == req) {
2169                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2170                 if (task->tk_client->cl_discrtry)
2171                         xprt_conditional_disconnect(req->rq_xprt,
2172                                         req->rq_connect_cookie);
2173         }
2174 }
2175
2176 static __be32 *
2177 rpc_encode_header(struct rpc_task *task)
2178 {
2179         struct rpc_clnt *clnt = task->tk_client;
2180         struct rpc_rqst *req = task->tk_rqstp;
2181         __be32          *p = req->rq_svec[0].iov_base;
2182
2183         /* FIXME: check buffer size? */
2184
2185         p = xprt_skip_transport_header(req->rq_xprt, p);
2186         *p++ = req->rq_xid;             /* XID */
2187         *p++ = htonl(RPC_CALL);         /* CALL */
2188         *p++ = htonl(RPC_VERSION);      /* RPC version */
2189         *p++ = htonl(clnt->cl_prog);    /* program number */
2190         *p++ = htonl(clnt->cl_vers);    /* program version */
2191         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
2192         p = rpcauth_marshcred(task, p);
2193         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2194         return p;
2195 }
2196
2197 static __be32 *
2198 rpc_verify_header(struct rpc_task *task)
2199 {
2200         struct rpc_clnt *clnt = task->tk_client;
2201         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2202         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2203         __be32  *p = iov->iov_base;
2204         u32 n;
2205         int error = -EACCES;
2206
2207         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2208                 /* RFC-1014 says that the representation of XDR data must be a
2209                  * multiple of four bytes
2210                  * - if it isn't pointer subtraction in the NFS client may give
2211                  *   undefined results
2212                  */
2213                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
2214                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2215                        task->tk_rqstp->rq_rcv_buf.len);
2216                 error = -EIO;
2217                 goto out_err;
2218         }
2219         if ((len -= 3) < 0)
2220                 goto out_overflow;
2221
2222         p += 1; /* skip XID */
2223         if ((n = ntohl(*p++)) != RPC_REPLY) {
2224                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2225                         task->tk_pid, __func__, n);
2226                 error = -EIO;
2227                 goto out_garbage;
2228         }
2229
2230         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2231                 if (--len < 0)
2232                         goto out_overflow;
2233                 switch ((n = ntohl(*p++))) {
2234                 case RPC_AUTH_ERROR:
2235                         break;
2236                 case RPC_MISMATCH:
2237                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2238                                 task->tk_pid, __func__);
2239                         error = -EPROTONOSUPPORT;
2240                         goto out_err;
2241                 default:
2242                         dprintk("RPC: %5u %s: RPC call rejected, "
2243                                 "unknown error: %x\n",
2244                                 task->tk_pid, __func__, n);
2245                         error = -EIO;
2246                         goto out_err;
2247                 }
2248                 if (--len < 0)
2249                         goto out_overflow;
2250                 switch ((n = ntohl(*p++))) {
2251                 case RPC_AUTH_REJECTEDCRED:
2252                 case RPC_AUTH_REJECTEDVERF:
2253                 case RPCSEC_GSS_CREDPROBLEM:
2254                 case RPCSEC_GSS_CTXPROBLEM:
2255                         if (!task->tk_cred_retry)
2256                                 break;
2257                         task->tk_cred_retry--;
2258                         dprintk("RPC: %5u %s: retry stale creds\n",
2259                                         task->tk_pid, __func__);
2260                         rpcauth_invalcred(task);
2261                         /* Ensure we obtain a new XID! */
2262                         xprt_release(task);
2263                         task->tk_action = call_reserve;
2264                         goto out_retry;
2265                 case RPC_AUTH_BADCRED:
2266                 case RPC_AUTH_BADVERF:
2267                         /* possibly garbled cred/verf? */
2268                         if (!task->tk_garb_retry)
2269                                 break;
2270                         task->tk_garb_retry--;
2271                         dprintk("RPC: %5u %s: retry garbled creds\n",
2272                                         task->tk_pid, __func__);
2273                         task->tk_action = call_bind;
2274                         goto out_retry;
2275                 case RPC_AUTH_TOOWEAK:
2276                         rcu_read_lock();
2277                         printk(KERN_NOTICE "RPC: server %s requires stronger "
2278                                "authentication.\n",
2279                                rcu_dereference(clnt->cl_xprt)->servername);
2280                         rcu_read_unlock();
2281                         break;
2282                 default:
2283                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
2284                                         task->tk_pid, __func__, n);
2285                         error = -EIO;
2286                 }
2287                 dprintk("RPC: %5u %s: call rejected %d\n",
2288                                 task->tk_pid, __func__, n);
2289                 goto out_err;
2290         }
2291         p = rpcauth_checkverf(task, p);
2292         if (IS_ERR(p)) {
2293                 error = PTR_ERR(p);
2294                 dprintk("RPC: %5u %s: auth check failed with %d\n",
2295                                 task->tk_pid, __func__, error);
2296                 goto out_garbage;               /* bad verifier, retry */
2297         }
2298         len = p - (__be32 *)iov->iov_base - 1;
2299         if (len < 0)
2300                 goto out_overflow;
2301         switch ((n = ntohl(*p++))) {
2302         case RPC_SUCCESS:
2303                 return p;
2304         case RPC_PROG_UNAVAIL:
2305                 dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2306                                 "by server %s\n", task->tk_pid, __func__,
2307                                 (unsigned int)clnt->cl_prog,
2308                                 rcu_dereference(clnt->cl_xprt)->servername);
2309                 error = -EPFNOSUPPORT;
2310                 goto out_err;
2311         case RPC_PROG_MISMATCH:
2312                 dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2313                                 "by server %s\n", task->tk_pid, __func__,
2314                                 (unsigned int)clnt->cl_prog,
2315                                 (unsigned int)clnt->cl_vers,
2316                                 rcu_dereference(clnt->cl_xprt)->servername);
2317                 error = -EPROTONOSUPPORT;
2318                 goto out_err;
2319         case RPC_PROC_UNAVAIL:
2320                 dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2321                                 "version %u on server %s\n",
2322                                 task->tk_pid, __func__,
2323                                 rpc_proc_name(task),
2324                                 clnt->cl_prog, clnt->cl_vers,
2325                                 rcu_dereference(clnt->cl_xprt)->servername);
2326                 error = -EOPNOTSUPP;
2327                 goto out_err;
2328         case RPC_GARBAGE_ARGS:
2329                 dprintk("RPC: %5u %s: server saw garbage\n",
2330                                 task->tk_pid, __func__);
2331                 break;                  /* retry */
2332         default:
2333                 dprintk("RPC: %5u %s: server accept status: %x\n",
2334                                 task->tk_pid, __func__, n);
2335                 /* Also retry */
2336         }
2337
2338 out_garbage:
2339         clnt->cl_stats->rpcgarbage++;
2340         if (task->tk_garb_retry) {
2341                 task->tk_garb_retry--;
2342                 dprintk("RPC: %5u %s: retrying\n",
2343                                 task->tk_pid, __func__);
2344                 task->tk_action = call_bind;
2345 out_retry:
2346                 return ERR_PTR(-EAGAIN);
2347         }
2348 out_err:
2349         rpc_exit(task, error);
2350         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2351                         __func__, error);
2352         return ERR_PTR(error);
2353 out_overflow:
2354         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2355                         __func__);
2356         goto out_garbage;
2357 }
2358
2359 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2360 {
2361 }
2362
2363 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2364 {
2365         return 0;
2366 }
2367
2368 static struct rpc_procinfo rpcproc_null = {
2369         .p_encode = rpcproc_encode_null,
2370         .p_decode = rpcproc_decode_null,
2371 };
2372
2373 static int rpc_ping(struct rpc_clnt *clnt)
2374 {
2375         struct rpc_message msg = {
2376                 .rpc_proc = &rpcproc_null,
2377         };
2378         int err;
2379         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2380         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2381         put_rpccred(msg.rpc_cred);
2382         return err;
2383 }
2384
2385 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2386 {
2387         struct rpc_message msg = {
2388                 .rpc_proc = &rpcproc_null,
2389                 .rpc_cred = cred,
2390         };
2391         struct rpc_task_setup task_setup_data = {
2392                 .rpc_client = clnt,
2393                 .rpc_message = &msg,
2394                 .callback_ops = &rpc_default_ops,
2395                 .flags = flags,
2396         };
2397         return rpc_run_task(&task_setup_data);
2398 }
2399 EXPORT_SYMBOL_GPL(rpc_call_null);
2400
2401 #ifdef RPC_DEBUG
2402 static void rpc_show_header(void)
2403 {
2404         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2405                 "-timeout ---ops--\n");
2406 }
2407
2408 static void rpc_show_task(const struct rpc_clnt *clnt,
2409                           const struct rpc_task *task)
2410 {
2411         const char *rpc_waitq = "none";
2412
2413         if (RPC_IS_QUEUED(task))
2414                 rpc_waitq = rpc_qname(task->tk_waitqueue);
2415
2416         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2417                 task->tk_pid, task->tk_flags, task->tk_status,
2418                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2419                 clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
2420                 task->tk_action, rpc_waitq);
2421 }
2422
2423 void rpc_show_tasks(struct net *net)
2424 {
2425         struct rpc_clnt *clnt;
2426         struct rpc_task *task;
2427         int header = 0;
2428         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2429
2430         spin_lock(&sn->rpc_client_lock);
2431         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2432                 spin_lock(&clnt->cl_lock);
2433                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2434                         if (!header) {
2435                                 rpc_show_header();
2436                                 header++;
2437                         }
2438                         rpc_show_task(clnt, task);
2439                 }
2440                 spin_unlock(&clnt->cl_lock);
2441         }
2442         spin_unlock(&sn->rpc_client_lock);
2443 }
2444 #endif