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 struct rpc_clnt *rpc_create_xprt(struct rpc_create_args *args,
 442                                         struct rpc_xprt *xprt)
 443 {
 444         struct rpc_clnt *clnt = NULL;
 445
 446         clnt = rpc_new_client(args, xprt, NULL);
 447         if (IS_ERR(clnt))
 448                 return clnt;
 449
 450         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 451                 int err = rpc_ping(clnt);
 452                 if (err != 0) {
 453                         rpc_shutdown_client(clnt);
 454                         return ERR_PTR(err);
 455                 }
 456         }
 457
 458         clnt->cl_softrtry = 1;
 459         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 460                 clnt->cl_softrtry = 0;
 461
 462         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 463                 clnt->cl_autobind = 1;
 464         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 465                 clnt->cl_discrtry = 1;
 466         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 467                 clnt->cl_chatty = 1;
 468
 469         return clnt;
 470 }
 471 EXPORT_SYMBOL_GPL(rpc_create_xprt);
 472
 473 /**
 474  * rpc_create - create an RPC client and transport with one call
 475  * @args: rpc_clnt create argument structure
 476  *
 477  * Creates and initializes an RPC transport and an RPC client.
 478  *
 479  * It can ping the server in order to determine if it is up, and to see if
 480  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 481  * this behavior so asynchronous tasks can also use rpc_create.
 482  */
 483 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 484 {
 485         struct rpc_xprt *xprt;
 486         struct xprt_create xprtargs = {
 487                 .net = args->net,
 488                 .ident = args->protocol,
 489                 .srcaddr = args->saddress,
 490                 .dstaddr = args->address,
 491                 .addrlen = args->addrsize,
 492                 .servername = args->servername,
 493                 .bc_xprt = args->bc_xprt,
 494         };
 495         char servername[48];
 496
 497         if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
 498                 xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
 499         if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
 500                 xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
 501         /*
 502          * If the caller chooses not to specify a hostname, whip
 503          * up a string representation of the passed-in address.
 504          */
 505         if (xprtargs.servername == NULL) {
 506                 struct sockaddr_un *sun =
 507                                 (struct sockaddr_un *)args->address;
 508                 struct sockaddr_in *sin =
 509                                 (struct sockaddr_in *)args->address;
 510                 struct sockaddr_in6 *sin6 =
 511                                 (struct sockaddr_in6 *)args->address;
 512
 513                 servername[0] = '\0';
 514                 switch (args->address->sa_family) {
 515                 case AF_LOCAL:
 516                         snprintf(servername, sizeof(servername), "%s",
 517                                  sun->sun_path);
 518                         break;
 519                 case AF_INET:
 520                         snprintf(servername, sizeof(servername), "%pI4",
 521                                  &sin->sin_addr.s_addr);
 522                         break;
 523                 case AF_INET6:
 524                         snprintf(servername, sizeof(servername), "%pI6",
 525                                  &sin6->sin6_addr);
 526                         break;
 527                 default:
 528                         /* caller wants default server name, but
 529                          * address family isn't recognized. */
 530                         return ERR_PTR(-EINVAL);
 531                 }
 532                 xprtargs.servername = servername;
 533         }
 534
 535         xprt = xprt_create_transport(&xprtargs);
 536         if (IS_ERR(xprt))
 537                 return (struct rpc_clnt *)xprt;
 538
 539         /*
 540          * By default, kernel RPC client connects from a reserved port.
 541          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 542          * but it is always enabled for rpciod, which handles the connect
 543          * operation.
 544          */
 545         xprt->resvport = 1;
 546         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 547                 xprt->resvport = 0;
 548
 549         return rpc_create_xprt(args, xprt);
 550 }
 551 EXPORT_SYMBOL_GPL(rpc_create);
 552
 553 /*
 554  * This function clones the RPC client structure. It allows us to share the
 555  * same transport while varying parameters such as the authentication
 556  * flavour.
 557  */
 558 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
 559                                            struct rpc_clnt *clnt)
 560 {
 561         struct rpc_xprt *xprt;
 562         struct rpc_clnt *new;
 563         int err;
 564
 565         err = -ENOMEM;
 566         rcu_read_lock();
 567         xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
 568         rcu_read_unlock();
 569         if (xprt == NULL)
 570                 goto out_err;
 571         args->servername = xprt->servername;
 572
 573         new = rpc_new_client(args, xprt, clnt);
 574         if (IS_ERR(new)) {
 575                 err = PTR_ERR(new);
 576                 goto out_err;
 577         }
 578
 579         /* Turn off autobind on clones */
 580         new->cl_autobind = 0;
 581         new->cl_softrtry = clnt->cl_softrtry;
 582         new->cl_discrtry = clnt->cl_discrtry;
 583         new->cl_chatty = clnt->cl_chatty;
 584         return new;
 585
 586 out_err:
 587         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 588         return ERR_PTR(err);
 589 }
 590
 591 /**
 592  * rpc_clone_client - Clone an RPC client structure
 593  *
 594  * @clnt: RPC client whose parameters are copied
 595  *
 596  * Returns a fresh RPC client or an ERR_PTR.
 597  */
 598 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
 599 {
 600         struct rpc_create_args args = {
 601                 .program        = clnt->cl_program,
 602                 .prognumber     = clnt->cl_prog,
 603                 .version        = clnt->cl_vers,
 604                 .authflavor     = clnt->cl_auth->au_flavor,
 605         };
 606         return __rpc_clone_client(&args, clnt);
 607 }
 608 EXPORT_SYMBOL_GPL(rpc_clone_client);
 609
 610 /**
 611  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
 612  *
 613  * @clnt: RPC client whose parameters are copied
 614  * @flavor: security flavor for new client
 615  *
 616  * Returns a fresh RPC client or an ERR_PTR.
 617  */
 618 struct rpc_clnt *
 619 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
 620 {
 621         struct rpc_create_args args = {
 622                 .program        = clnt->cl_program,
 623                 .prognumber     = clnt->cl_prog,
 624                 .version        = clnt->cl_vers,
 625                 .authflavor     = flavor,
 626         };
 627         return __rpc_clone_client(&args, clnt);
 628 }
 629 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
 630
 631 /**
 632  * rpc_switch_client_transport: switch the RPC transport on the fly
 633  * @clnt: pointer to a struct rpc_clnt
 634  * @args: pointer to the new transport arguments
 635  * @timeout: pointer to the new timeout parameters
 636  *
 637  * This function allows the caller to switch the RPC transport for the
 638  * rpc_clnt structure 'clnt' to allow it to connect to a mirrored NFS
 639  * server, for instance.  It assumes that the caller has ensured that
 640  * there are no active RPC tasks by using some form of locking.
 641  *
 642  * Returns zero if "clnt" is now using the new xprt.  Otherwise a
 643  * negative errno is returned, and "clnt" continues to use the old
 644  * xprt.
 645  */
 646 int rpc_switch_client_transport(struct rpc_clnt *clnt,
 647                 struct xprt_create *args,
 648                 const struct rpc_timeout *timeout)
 649 {
 650         const struct rpc_timeout *old_timeo;
 651         rpc_authflavor_t pseudoflavor;
 652         struct rpc_xprt *xprt, *old;
 653         struct rpc_clnt *parent;
 654         int err;
 655
 656         xprt = xprt_create_transport(args);
 657         if (IS_ERR(xprt)) {
 658                 dprintk("RPC:       failed to create new xprt for clnt %p\n",
 659                         clnt);
 660                 return PTR_ERR(xprt);
 661         }
 662
 663         pseudoflavor = clnt->cl_auth->au_flavor;
 664
 665         old_timeo = clnt->cl_timeout;
 666         old = rpc_clnt_set_transport(clnt, xprt, timeout);
 667
 668         rpc_unregister_client(clnt);
 669         __rpc_clnt_remove_pipedir(clnt);
 670
 671         /*
 672          * A new transport was created.  "clnt" therefore
 673          * becomes the root of a new cl_parent tree.  clnt's
 674          * children, if it has any, still point to the old xprt.
 675          */
 676         parent = clnt->cl_parent;
 677         clnt->cl_parent = clnt;
 678
 679         /*
 680          * The old rpc_auth cache cannot be re-used.  GSS
 681          * contexts in particular are between a single
 682          * client and server.
 683          */
 684         err = rpc_client_register(clnt, pseudoflavor, NULL);
 685         if (err)
 686                 goto out_revert;
 687
 688         synchronize_rcu();
 689         if (parent != clnt)
 690                 rpc_release_client(parent);
 691         xprt_put(old);
 692         dprintk("RPC:       replaced xprt for clnt %p\n", clnt);
 693         return 0;
 694
 695 out_revert:
 696         rpc_clnt_set_transport(clnt, old, old_timeo);
 697         clnt->cl_parent = parent;
 698         rpc_client_register(clnt, pseudoflavor, NULL);
 699         xprt_put(xprt);
 700         dprintk("RPC:       failed to switch xprt for clnt %p\n", clnt);
 701         return err;
 702 }
 703 EXPORT_SYMBOL_GPL(rpc_switch_client_transport);
 704
 705 /*
 706  * Kill all tasks for the given client.
 707  * XXX: kill their descendants as well?
 708  */
 709 void rpc_killall_tasks(struct rpc_clnt *clnt)
 710 {
 711         struct rpc_task *rovr;
 712
 713
 714         if (list_empty(&clnt->cl_tasks))
 715                 return;
 716         dprintk("RPC:       killing all tasks for client %p\n", clnt);
 717         /*
 718          * Spin lock all_tasks to prevent changes...
 719          */
 720         spin_lock(&clnt->cl_lock);
 721         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
 722                 if (!RPC_IS_ACTIVATED(rovr))
 723                         continue;
 724                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
 725                         rovr->tk_flags |= RPC_TASK_KILLED;
 726                         rpc_exit(rovr, -EIO);
 727                         if (RPC_IS_QUEUED(rovr))
 728                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
 729                                                         rovr);
 730                 }
 731         }
 732         spin_unlock(&clnt->cl_lock);
 733 }
 734 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
 735
 736 /*
 737  * Properly shut down an RPC client, terminating all outstanding
 738  * requests.
 739  */
 740 void rpc_shutdown_client(struct rpc_clnt *clnt)
 741 {
 742         might_sleep();
 743
 744         dprintk_rcu("RPC:       shutting down %s client for %s\n",
 745                         clnt->cl_program->name,
 746                         rcu_dereference(clnt->cl_xprt)->servername);
 747
 748         while (!list_empty(&clnt->cl_tasks)) {
 749                 rpc_killall_tasks(clnt);
 750                 wait_event_timeout(destroy_wait,
 751                         list_empty(&clnt->cl_tasks), 1*HZ);
 752         }
 753
 754         rpc_release_client(clnt);
 755 }
 756 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 757
 758 /*
 759  * Free an RPC client
 760  */
 761 static struct rpc_clnt *
 762 rpc_free_client(struct rpc_clnt *clnt)
 763 {
 764         struct rpc_clnt *parent = NULL;
 765
 766         dprintk_rcu("RPC:       destroying %s client for %s\n",
 767                         clnt->cl_program->name,
 768                         rcu_dereference(clnt->cl_xprt)->servername);
 769         if (clnt->cl_parent != clnt)
 770                 parent = clnt->cl_parent;
 771         rpc_clnt_remove_pipedir(clnt);
 772         rpc_unregister_client(clnt);
 773         rpc_free_iostats(clnt->cl_metrics);
 774         clnt->cl_metrics = NULL;
 775         xprt_put(rcu_dereference_raw(clnt->cl_xprt));
 776         rpciod_down();
 777         rpc_free_clid(clnt);
 778         kfree(clnt);
 779         return parent;
 780 }
 781
 782 /*
 783  * Free an RPC client
 784  */
 785 static struct rpc_clnt *
 786 rpc_free_auth(struct rpc_clnt *clnt)
 787 {
 788         if (clnt->cl_auth == NULL)
 789                 return rpc_free_client(clnt);
 790
 791         /*
 792          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 793          *       release remaining GSS contexts. This mechanism ensures
 794          *       that it can do so safely.
 795          */
 796         atomic_inc(&clnt->cl_count);
 797         rpcauth_release(clnt->cl_auth);
 798         clnt->cl_auth = NULL;
 799         if (atomic_dec_and_test(&clnt->cl_count))
 800                 return rpc_free_client(clnt);
 801         return NULL;
 802 }
 803
 804 /*
 805  * Release reference to the RPC client
 806  */
 807 void
 808 rpc_release_client(struct rpc_clnt *clnt)
 809 {
 810         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 811
 812         do {
 813                 if (list_empty(&clnt->cl_tasks))
 814                         wake_up(&destroy_wait);
 815                 if (!atomic_dec_and_test(&clnt->cl_count))
 816                         break;
 817                 clnt = rpc_free_auth(clnt);
 818         } while (clnt != NULL);
 819 }
 820 EXPORT_SYMBOL_GPL(rpc_release_client);
 821
 822 /**
 823  * rpc_bind_new_program - bind a new RPC program to an existing client
 824  * @old: old rpc_client
 825  * @program: rpc program to set
 826  * @vers: rpc program version
 827  *
 828  * Clones the rpc client and sets up a new RPC program. This is mainly
 829  * of use for enabling different RPC programs to share the same transport.
 830  * The Sun NFSv2/v3 ACL protocol can do this.
 831  */
 832 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 833                                       const struct rpc_program *program,
 834                                       u32 vers)
 835 {
 836         struct rpc_create_args args = {
 837                 .program        = program,
 838                 .prognumber     = program->number,
 839                 .version        = vers,
 840                 .authflavor     = old->cl_auth->au_flavor,
 841         };
 842         struct rpc_clnt *clnt;
 843         int err;
 844
 845         clnt = __rpc_clone_client(&args, old);
 846         if (IS_ERR(clnt))
 847                 goto out;
 848         err = rpc_ping(clnt);
 849         if (err != 0) {
 850                 rpc_shutdown_client(clnt);
 851                 clnt = ERR_PTR(err);
 852         }
 853 out:
 854         return clnt;
 855 }
 856 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 857
 858 void rpc_task_release_client(struct rpc_task *task)
 859 {
 860         struct rpc_clnt *clnt = task->tk_client;
 861
 862         if (clnt != NULL) {
 863                 /* Remove from client task list */
 864                 spin_lock(&clnt->cl_lock);
 865                 list_del(&task->tk_task);
 866                 spin_unlock(&clnt->cl_lock);
 867                 task->tk_client = NULL;
 868
 869                 rpc_release_client(clnt);
 870         }
 871 }
 872
 873 static
 874 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
 875 {
 876         if (clnt != NULL) {
 877                 rpc_task_release_client(task);
 878                 task->tk_client = clnt;
 879                 atomic_inc(&clnt->cl_count);
 880                 if (clnt->cl_softrtry)
 881                         task->tk_flags |= RPC_TASK_SOFT;
 882                 if (clnt->cl_noretranstimeo)
 883                         task->tk_flags |= RPC_TASK_NO_RETRANS_TIMEOUT;
 884                 if (sk_memalloc_socks()) {
 885                         struct rpc_xprt *xprt;
 886
 887                         rcu_read_lock();
 888                         xprt = rcu_dereference(clnt->cl_xprt);
 889                         if (xprt->swapper)
 890                                 task->tk_flags |= RPC_TASK_SWAPPER;
 891                         rcu_read_unlock();
 892                 }
 893                 /* Add to the client's list of all tasks */
 894                 spin_lock(&clnt->cl_lock);
 895                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
 896                 spin_unlock(&clnt->cl_lock);
 897         }
 898 }
 899
 900 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
 901 {
 902         rpc_task_release_client(task);
 903         rpc_task_set_client(task, clnt);
 904 }
 905 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
 906
 907
 908 static void
 909 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
 910 {
 911         if (msg != NULL) {
 912                 task->tk_msg.rpc_proc = msg->rpc_proc;
 913                 task->tk_msg.rpc_argp = msg->rpc_argp;
 914                 task->tk_msg.rpc_resp = msg->rpc_resp;
 915                 if (msg->rpc_cred != NULL)
 916                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
 917         }
 918 }
 919
 920 /*
 921  * Default callback for async RPC calls
 922  */
 923 static void
 924 rpc_default_callback(struct rpc_task *task, void *data)
 925 {
 926 }
 927
 928 static const struct rpc_call_ops rpc_default_ops = {
 929         .rpc_call_done = rpc_default_callback,
 930 };
 931
 932 /**
 933  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 934  * @task_setup_data: pointer to task initialisation data
 935  */
 936 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 937 {
 938         struct rpc_task *task;
 939
 940         task = rpc_new_task(task_setup_data);
 941         if (IS_ERR(task))
 942                 goto out;
 943
 944         rpc_task_set_client(task, task_setup_data->rpc_client);
 945         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
 946
 947         if (task->tk_action == NULL)
 948                 rpc_call_start(task);
 949
 950         atomic_inc(&task->tk_count);
 951         rpc_execute(task);
 952 out:
 953         return task;
 954 }
 955 EXPORT_SYMBOL_GPL(rpc_run_task);
 956
 957 /**
 958  * rpc_call_sync - Perform a synchronous RPC call
 959  * @clnt: pointer to RPC client
 960  * @msg: RPC call parameters
 961  * @flags: RPC call flags
 962  */
 963 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 964 {
 965         struct rpc_task *task;
 966         struct rpc_task_setup task_setup_data = {
 967                 .rpc_client = clnt,
 968                 .rpc_message = msg,
 969                 .callback_ops = &rpc_default_ops,
 970                 .flags = flags,
 971         };
 972         int status;
 973
 974         WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
 975         if (flags & RPC_TASK_ASYNC) {
 976                 rpc_release_calldata(task_setup_data.callback_ops,
 977                         task_setup_data.callback_data);
 978                 return -EINVAL;
 979         }
 980
 981         task = rpc_run_task(&task_setup_data);
 982         if (IS_ERR(task))
 983                 return PTR_ERR(task);
 984         status = task->tk_status;
 985         rpc_put_task(task);
 986         return status;
 987 }
 988 EXPORT_SYMBOL_GPL(rpc_call_sync);
 989
 990 /**
 991  * rpc_call_async - Perform an asynchronous RPC call
 992  * @clnt: pointer to RPC client
 993  * @msg: RPC call parameters
 994  * @flags: RPC call flags
 995  * @tk_ops: RPC call ops
 996  * @data: user call data
 997  */
 998 int
 999 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
1000                const struct rpc_call_ops *tk_ops, void *data)
1001 {
1002         struct rpc_task *task;
1003         struct rpc_task_setup task_setup_data = {
1004                 .rpc_client = clnt,
1005                 .rpc_message = msg,
1006                 .callback_ops = tk_ops,
1007                 .callback_data = data,
1008                 .flags = flags|RPC_TASK_ASYNC,
1009         };
1010
1011         task = rpc_run_task(&task_setup_data);
1012         if (IS_ERR(task))
1013                 return PTR_ERR(task);
1014         rpc_put_task(task);
1015         return 0;
1016 }
1017 EXPORT_SYMBOL_GPL(rpc_call_async);
1018
1019 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1020 /**
1021  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
1022  * rpc_execute against it
1023  * @req: RPC request
1024  * @tk_ops: RPC call ops
1025  */
1026 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
1027                                 const struct rpc_call_ops *tk_ops)
1028 {
1029         struct rpc_task *task;
1030         struct xdr_buf *xbufp = &req->rq_snd_buf;
1031         struct rpc_task_setup task_setup_data = {
1032                 .callback_ops = tk_ops,
1033         };
1034
1035         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
1036         /*
1037          * Create an rpc_task to send the data
1038          */
1039         task = rpc_new_task(&task_setup_data);
1040         if (IS_ERR(task)) {
1041                 xprt_free_bc_request(req);
1042                 goto out;
1043         }
1044         task->tk_rqstp = req;
1045
1046         /*
1047          * Set up the xdr_buf length.
1048          * This also indicates that the buffer is XDR encoded already.
1049          */
1050         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
1051                         xbufp->tail[0].iov_len;
1052
1053         task->tk_action = call_bc_transmit;
1054         atomic_inc(&task->tk_count);
1055         WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
1056         rpc_execute(task);
1057
1058 out:
1059         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
1060         return task;
1061 }
1062 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1063
1064 void
1065 rpc_call_start(struct rpc_task *task)
1066 {
1067         task->tk_action = call_start;
1068 }
1069 EXPORT_SYMBOL_GPL(rpc_call_start);
1070
1071 /**
1072  * rpc_peeraddr - extract remote peer address from clnt's xprt
1073  * @clnt: RPC client structure
1074  * @buf: target buffer
1075  * @bufsize: length of target buffer
1076  *
1077  * Returns the number of bytes that are actually in the stored address.
1078  */
1079 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
1080 {
1081         size_t bytes;
1082         struct rpc_xprt *xprt;
1083
1084         rcu_read_lock();
1085         xprt = rcu_dereference(clnt->cl_xprt);
1086
1087         bytes = xprt->addrlen;
1088         if (bytes > bufsize)
1089                 bytes = bufsize;
1090         memcpy(buf, &xprt->addr, bytes);
1091         rcu_read_unlock();
1092
1093         return bytes;
1094 }
1095 EXPORT_SYMBOL_GPL(rpc_peeraddr);
1096
1097 /**
1098  * rpc_peeraddr2str - return remote peer address in printable format
1099  * @clnt: RPC client structure
1100  * @format: address format
1101  *
1102  * NB: the lifetime of the memory referenced by the returned pointer is
1103  * the same as the rpc_xprt itself.  As long as the caller uses this
1104  * pointer, it must hold the RCU read lock.
1105  */
1106 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
1107                              enum rpc_display_format_t format)
1108 {
1109         struct rpc_xprt *xprt;
1110
1111         xprt = rcu_dereference(clnt->cl_xprt);
1112
1113         if (xprt->address_strings[format] != NULL)
1114                 return xprt->address_strings[format];
1115         else
1116                 return "unprintable";
1117 }
1118 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
1119
1120 static const struct sockaddr_in rpc_inaddr_loopback = {
1121         .sin_family             = AF_INET,
1122         .sin_addr.s_addr        = htonl(INADDR_ANY),
1123 };
1124
1125 static const struct sockaddr_in6 rpc_in6addr_loopback = {
1126         .sin6_family            = AF_INET6,
1127         .sin6_addr              = IN6ADDR_ANY_INIT,
1128 };
1129
1130 /*
1131  * Try a getsockname() on a connected datagram socket.  Using a
1132  * connected datagram socket prevents leaving a socket in TIME_WAIT.
1133  * This conserves the ephemeral port number space.
1134  *
1135  * Returns zero and fills in "buf" if successful; otherwise, a
1136  * negative errno is returned.
1137  */
1138 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1139                         struct sockaddr *buf, int buflen)
1140 {
1141         struct socket *sock;
1142         int err;
1143
1144         err = __sock_create(net, sap->sa_family,
1145                                 SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1146         if (err < 0) {
1147                 dprintk("RPC:       can't create UDP socket (%d)\n", err);
1148                 goto out;
1149         }
1150
1151         switch (sap->sa_family) {
1152         case AF_INET:
1153                 err = kernel_bind(sock,
1154                                 (struct sockaddr *)&rpc_inaddr_loopback,
1155                                 sizeof(rpc_inaddr_loopback));
1156                 break;
1157         case AF_INET6:
1158                 err = kernel_bind(sock,
1159                                 (struct sockaddr *)&rpc_in6addr_loopback,
1160                                 sizeof(rpc_in6addr_loopback));
1161                 break;
1162         default:
1163                 err = -EAFNOSUPPORT;
1164                 goto out;
1165         }
1166         if (err < 0) {
1167                 dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1168                 goto out_release;
1169         }
1170
1171         err = kernel_connect(sock, sap, salen, 0);
1172         if (err < 0) {
1173                 dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1174                 goto out_release;
1175         }
1176
1177         err = kernel_getsockname(sock, buf, &buflen);
1178         if (err < 0) {
1179                 dprintk("RPC:       getsockname failed (%d)\n", err);
1180                 goto out_release;
1181         }
1182
1183         err = 0;
1184         if (buf->sa_family == AF_INET6) {
1185                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1186                 sin6->sin6_scope_id = 0;
1187         }
1188         dprintk("RPC:       %s succeeded\n", __func__);
1189
1190 out_release:
1191         sock_release(sock);
1192 out:
1193         return err;
1194 }
1195
1196 /*
1197  * Scraping a connected socket failed, so we don't have a useable
1198  * local address.  Fallback: generate an address that will prevent
1199  * the server from calling us back.
1200  *
1201  * Returns zero and fills in "buf" if successful; otherwise, a
1202  * negative errno is returned.
1203  */
1204 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1205 {
1206         switch (family) {
1207         case AF_INET:
1208                 if (buflen < sizeof(rpc_inaddr_loopback))
1209                         return -EINVAL;
1210                 memcpy(buf, &rpc_inaddr_loopback,
1211                                 sizeof(rpc_inaddr_loopback));
1212                 break;
1213         case AF_INET6:
1214                 if (buflen < sizeof(rpc_in6addr_loopback))
1215                         return -EINVAL;
1216                 memcpy(buf, &rpc_in6addr_loopback,
1217                                 sizeof(rpc_in6addr_loopback));
1218         default:
1219                 dprintk("RPC:       %s: address family not supported\n",
1220                         __func__);
1221                 return -EAFNOSUPPORT;
1222         }
1223         dprintk("RPC:       %s: succeeded\n", __func__);
1224         return 0;
1225 }
1226
1227 /**
1228  * rpc_localaddr - discover local endpoint address for an RPC client
1229  * @clnt: RPC client structure
1230  * @buf: target buffer
1231  * @buflen: size of target buffer, in bytes
1232  *
1233  * Returns zero and fills in "buf" and "buflen" if successful;
1234  * otherwise, a negative errno is returned.
1235  *
1236  * This works even if the underlying transport is not currently connected,
1237  * or if the upper layer never previously provided a source address.
1238  *
1239  * The result of this function call is transient: multiple calls in
1240  * succession may give different results, depending on how local
1241  * networking configuration changes over time.
1242  */
1243 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1244 {
1245         struct sockaddr_storage address;
1246         struct sockaddr *sap = (struct sockaddr *)&address;
1247         struct rpc_xprt *xprt;
1248         struct net *net;
1249         size_t salen;
1250         int err;
1251
1252         rcu_read_lock();
1253         xprt = rcu_dereference(clnt->cl_xprt);
1254         salen = xprt->addrlen;
1255         memcpy(sap, &xprt->addr, salen);
1256         net = get_net(xprt->xprt_net);
1257         rcu_read_unlock();
1258
1259         rpc_set_port(sap, 0);
1260         err = rpc_sockname(net, sap, salen, buf, buflen);
1261         put_net(net);
1262         if (err != 0)
1263                 /* Couldn't discover local address, return ANYADDR */
1264                 return rpc_anyaddr(sap->sa_family, buf, buflen);
1265         return 0;
1266 }
1267 EXPORT_SYMBOL_GPL(rpc_localaddr);
1268
1269 void
1270 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1271 {
1272         struct rpc_xprt *xprt;
1273
1274         rcu_read_lock();
1275         xprt = rcu_dereference(clnt->cl_xprt);
1276         if (xprt->ops->set_buffer_size)
1277                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1278         rcu_read_unlock();
1279 }
1280 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1281
1282 /**
1283  * rpc_protocol - Get transport protocol number for an RPC client
1284  * @clnt: RPC client to query
1285  *
1286  */
1287 int rpc_protocol(struct rpc_clnt *clnt)
1288 {
1289         int protocol;
1290
1291         rcu_read_lock();
1292         protocol = rcu_dereference(clnt->cl_xprt)->prot;
1293         rcu_read_unlock();
1294         return protocol;
1295 }
1296 EXPORT_SYMBOL_GPL(rpc_protocol);
1297
1298 /**
1299  * rpc_net_ns - Get the network namespace for this RPC client
1300  * @clnt: RPC client to query
1301  *
1302  */
1303 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1304 {
1305         struct net *ret;
1306
1307         rcu_read_lock();
1308         ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1309         rcu_read_unlock();
1310         return ret;
1311 }
1312 EXPORT_SYMBOL_GPL(rpc_net_ns);
1313
1314 /**
1315  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1316  * @clnt: RPC client to query
1317  *
1318  * For stream transports, this is one RPC record fragment (see RFC
1319  * 1831), as we don't support multi-record requests yet.  For datagram
1320  * transports, this is the size of an IP packet minus the IP, UDP, and
1321  * RPC header sizes.
1322  */
1323 size_t rpc_max_payload(struct rpc_clnt *clnt)
1324 {
1325         size_t ret;
1326
1327         rcu_read_lock();
1328         ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1329         rcu_read_unlock();
1330         return ret;
1331 }
1332 EXPORT_SYMBOL_GPL(rpc_max_payload);
1333
1334 /**
1335  * rpc_get_timeout - Get timeout for transport in units of HZ
1336  * @clnt: RPC client to query
1337  */
1338 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1339 {
1340         unsigned long ret;
1341
1342         rcu_read_lock();
1343         ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1344         rcu_read_unlock();
1345         return ret;
1346 }
1347 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1348
1349 /**
1350  * rpc_force_rebind - force transport to check that remote port is unchanged
1351  * @clnt: client to rebind
1352  *
1353  */
1354 void rpc_force_rebind(struct rpc_clnt *clnt)
1355 {
1356         if (clnt->cl_autobind) {
1357                 rcu_read_lock();
1358                 xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1359                 rcu_read_unlock();
1360         }
1361 }
1362 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1363
1364 /*
1365  * Restart an (async) RPC call from the call_prepare state.
1366  * Usually called from within the exit handler.
1367  */
1368 int
1369 rpc_restart_call_prepare(struct rpc_task *task)
1370 {
1371         if (RPC_ASSASSINATED(task))
1372                 return 0;
1373         task->tk_action = call_start;
1374         task->tk_status = 0;
1375         if (task->tk_ops->rpc_call_prepare != NULL)
1376                 task->tk_action = rpc_prepare_task;
1377         return 1;
1378 }
1379 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1380
1381 /*
1382  * Restart an (async) RPC call. Usually called from within the
1383  * exit handler.
1384  */
1385 int
1386 rpc_restart_call(struct rpc_task *task)
1387 {
1388         if (RPC_ASSASSINATED(task))
1389                 return 0;
1390         task->tk_action = call_start;
1391         task->tk_status = 0;
1392         return 1;
1393 }
1394 EXPORT_SYMBOL_GPL(rpc_restart_call);
1395
1396 #ifdef RPC_DEBUG
1397 static const char *rpc_proc_name(const struct rpc_task *task)
1398 {
1399         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1400
1401         if (proc) {
1402                 if (proc->p_name)
1403                         return proc->p_name;
1404                 else
1405                         return "NULL";
1406         } else
1407                 return "no proc";
1408 }
1409 #endif
1410
1411 /*
1412  * 0.  Initial state
1413  *
1414  *     Other FSM states can be visited zero or more times, but
1415  *     this state is visited exactly once for each RPC.
1416  */
1417 static void
1418 call_start(struct rpc_task *task)
1419 {
1420         struct rpc_clnt *clnt = task->tk_client;
1421
1422         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1423                         clnt->cl_program->name, clnt->cl_vers,
1424                         rpc_proc_name(task),
1425                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
1426
1427         /* Increment call count */
1428         task->tk_msg.rpc_proc->p_count++;
1429         clnt->cl_stats->rpccnt++;
1430         task->tk_action = call_reserve;
1431 }
1432
1433 /*
1434  * 1.   Reserve an RPC call slot
1435  */
1436 static void
1437 call_reserve(struct rpc_task *task)
1438 {
1439         dprint_status(task);
1440
1441         task->tk_status  = 0;
1442         task->tk_action  = call_reserveresult;
1443         xprt_reserve(task);
1444 }
1445
1446 static void call_retry_reserve(struct rpc_task *task);
1447
1448 /*
1449  * 1b.  Grok the result of xprt_reserve()
1450  */
1451 static void
1452 call_reserveresult(struct rpc_task *task)
1453 {
1454         int status = task->tk_status;
1455
1456         dprint_status(task);
1457
1458         /*
1459          * After a call to xprt_reserve(), we must have either
1460          * a request slot or else an error status.
1461          */
1462         task->tk_status = 0;
1463         if (status >= 0) {
1464                 if (task->tk_rqstp) {
1465                         task->tk_action = call_refresh;
1466                         return;
1467                 }
1468
1469                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1470                                 __func__, status);
1471                 rpc_exit(task, -EIO);
1472                 return;
1473         }
1474
1475         /*
1476          * Even though there was an error, we may have acquired
1477          * a request slot somehow.  Make sure not to leak it.
1478          */
1479         if (task->tk_rqstp) {
1480                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1481                                 __func__, status);
1482                 xprt_release(task);
1483         }
1484
1485         switch (status) {
1486         case -ENOMEM:
1487                 rpc_delay(task, HZ >> 2);
1488         case -EAGAIN:   /* woken up; retry */
1489                 task->tk_action = call_retry_reserve;
1490                 return;
1491         case -EIO:      /* probably a shutdown */
1492                 break;
1493         default:
1494                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1495                                 __func__, status);
1496                 break;
1497         }
1498         rpc_exit(task, status);
1499 }
1500
1501 /*
1502  * 1c.  Retry reserving an RPC call slot
1503  */
1504 static void
1505 call_retry_reserve(struct rpc_task *task)
1506 {
1507         dprint_status(task);
1508
1509         task->tk_status  = 0;
1510         task->tk_action  = call_reserveresult;
1511         xprt_retry_reserve(task);
1512 }
1513
1514 /*
1515  * 2.   Bind and/or refresh the credentials
1516  */
1517 static void
1518 call_refresh(struct rpc_task *task)
1519 {
1520         dprint_status(task);
1521
1522         task->tk_action = call_refreshresult;
1523         task->tk_status = 0;
1524         task->tk_client->cl_stats->rpcauthrefresh++;
1525         rpcauth_refreshcred(task);
1526 }
1527
1528 /*
1529  * 2a.  Process the results of a credential refresh
1530  */
1531 static void
1532 call_refreshresult(struct rpc_task *task)
1533 {
1534         int status = task->tk_status;
1535
1536         dprint_status(task);
1537
1538         task->tk_status = 0;
1539         task->tk_action = call_refresh;
1540         switch (status) {
1541         case 0:
1542                 if (rpcauth_uptodatecred(task)) {
1543                         task->tk_action = call_allocate;
1544                         return;
1545                 }
1546                 /* Use rate-limiting and a max number of retries if refresh
1547                  * had status 0 but failed to update the cred.
1548                  */
1549         case -ETIMEDOUT:
1550                 rpc_delay(task, 3*HZ);
1551         case -EAGAIN:
1552                 status = -EACCES;
1553         case -EKEYEXPIRED:
1554                 if (!task->tk_cred_retry)
1555                         break;
1556                 task->tk_cred_retry--;
1557                 dprintk("RPC: %5u %s: retry refresh creds\n",
1558                                 task->tk_pid, __func__);
1559                 return;
1560         }
1561         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1562                                 task->tk_pid, __func__, status);
1563         rpc_exit(task, status);
1564 }
1565
1566 /*
1567  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1568  *      (Note: buffer memory is freed in xprt_release).
1569  */
1570 static void
1571 call_allocate(struct rpc_task *task)
1572 {
1573         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1574         struct rpc_rqst *req = task->tk_rqstp;
1575         struct rpc_xprt *xprt = req->rq_xprt;
1576         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1577
1578         dprint_status(task);
1579
1580         task->tk_status = 0;
1581         task->tk_action = call_bind;
1582
1583         if (req->rq_buffer)
1584                 return;
1585
1586         if (proc->p_proc != 0) {
1587                 BUG_ON(proc->p_arglen == 0);
1588                 if (proc->p_decode != NULL)
1589                         BUG_ON(proc->p_replen == 0);
1590         }
1591
1592         /*
1593          * Calculate the size (in quads) of the RPC call
1594          * and reply headers, and convert both values
1595          * to byte sizes.
1596          */
1597         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1598         req->rq_callsize <<= 2;
1599         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1600         req->rq_rcvsize <<= 2;
1601
1602         req->rq_buffer = xprt->ops->buf_alloc(task,
1603                                         req->rq_callsize + req->rq_rcvsize);
1604         if (req->rq_buffer != NULL)
1605                 return;
1606
1607         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1608
1609         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1610                 task->tk_action = call_allocate;
1611                 rpc_delay(task, HZ>>4);
1612                 return;
1613         }
1614
1615         rpc_exit(task, -ERESTARTSYS);
1616 }
1617
1618 static inline int
1619 rpc_task_need_encode(struct rpc_task *task)
1620 {
1621         return task->tk_rqstp->rq_snd_buf.len == 0;
1622 }
1623
1624 static inline void
1625 rpc_task_force_reencode(struct rpc_task *task)
1626 {
1627         task->tk_rqstp->rq_snd_buf.len = 0;
1628         task->tk_rqstp->rq_bytes_sent = 0;
1629 }
1630
1631 static inline void
1632 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1633 {
1634         buf->head[0].iov_base = start;
1635         buf->head[0].iov_len = len;
1636         buf->tail[0].iov_len = 0;
1637         buf->page_len = 0;
1638         buf->flags = 0;
1639         buf->len = 0;
1640         buf->buflen = len;
1641 }
1642
1643 /*
1644  * 3.   Encode arguments of an RPC call
1645  */
1646 static void
1647 rpc_xdr_encode(struct rpc_task *task)
1648 {
1649         struct rpc_rqst *req = task->tk_rqstp;
1650         kxdreproc_t     encode;
1651         __be32          *p;
1652
1653         dprint_status(task);
1654
1655         rpc_xdr_buf_init(&req->rq_snd_buf,
1656                          req->rq_buffer,
1657                          req->rq_callsize);
1658         rpc_xdr_buf_init(&req->rq_rcv_buf,
1659                          (char *)req->rq_buffer + req->rq_callsize,
1660                          req->rq_rcvsize);
1661
1662         p = rpc_encode_header(task);
1663         if (p == NULL) {
1664                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1665                 rpc_exit(task, -EIO);
1666                 return;
1667         }
1668
1669         encode = task->tk_msg.rpc_proc->p_encode;
1670         if (encode == NULL)
1671                 return;
1672
1673         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1674                         task->tk_msg.rpc_argp);
1675 }
1676
1677 /*
1678  * 4.   Get the server port number if not yet set
1679  */
1680 static void
1681 call_bind(struct rpc_task *task)
1682 {
1683         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1684
1685         dprint_status(task);
1686
1687         task->tk_action = call_connect;
1688         if (!xprt_bound(xprt)) {
1689                 task->tk_action = call_bind_status;
1690                 task->tk_timeout = xprt->bind_timeout;
1691                 xprt->ops->rpcbind(task);
1692         }
1693 }
1694
1695 /*
1696  * 4a.  Sort out bind result
1697  */
1698 static void
1699 call_bind_status(struct rpc_task *task)
1700 {
1701         int status = -EIO;
1702
1703         if (task->tk_status >= 0) {
1704                 dprint_status(task);
1705                 task->tk_status = 0;
1706                 task->tk_action = call_connect;
1707                 return;
1708         }
1709
1710         trace_rpc_bind_status(task);
1711         switch (task->tk_status) {
1712         case -ENOMEM:
1713                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1714                 rpc_delay(task, HZ >> 2);
1715                 goto retry_timeout;
1716         case -EACCES:
1717                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1718                                 "unavailable\n", task->tk_pid);
1719                 /* fail immediately if this is an RPC ping */
1720                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1721                         status = -EOPNOTSUPP;
1722                         break;
1723                 }
1724                 if (task->tk_rebind_retry == 0)
1725                         break;
1726                 task->tk_rebind_retry--;
1727                 rpc_delay(task, 3*HZ);
1728                 goto retry_timeout;
1729         case -ETIMEDOUT:
1730                 dprintk("RPC: %5u rpcbind request timed out\n",
1731                                 task->tk_pid);
1732                 goto retry_timeout;
1733         case -EPFNOSUPPORT:
1734                 /* server doesn't support any rpcbind version we know of */
1735                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1736                                 task->tk_pid);
1737                 break;
1738         case -EPROTONOSUPPORT:
1739                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1740                                 task->tk_pid);
1741                 goto retry_timeout;
1742         case -ECONNREFUSED:             /* connection problems */
1743         case -ECONNRESET:
1744         case -ECONNABORTED:
1745         case -ENOTCONN:
1746         case -EHOSTDOWN:
1747         case -EHOSTUNREACH:
1748         case -ENETUNREACH:
1749         case -EPIPE:
1750                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1751                                 task->tk_pid, task->tk_status);
1752                 if (!RPC_IS_SOFTCONN(task)) {
1753                         rpc_delay(task, 5*HZ);
1754                         goto retry_timeout;
1755                 }
1756                 status = task->tk_status;
1757                 break;
1758         default:
1759                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1760                                 task->tk_pid, -task->tk_status);
1761         }
1762
1763         rpc_exit(task, status);
1764         return;
1765
1766 retry_timeout:
1767         task->tk_status = 0;
1768         task->tk_action = call_timeout;
1769 }
1770
1771 /*
1772  * 4b.  Connect to the RPC server
1773  */
1774 static void
1775 call_connect(struct rpc_task *task)
1776 {
1777         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1778
1779         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1780                         task->tk_pid, xprt,
1781                         (xprt_connected(xprt) ? "is" : "is not"));
1782
1783         task->tk_action = call_transmit;
1784         if (!xprt_connected(xprt)) {
1785                 task->tk_action = call_connect_status;
1786                 if (task->tk_status < 0)
1787                         return;
1788                 if (task->tk_flags & RPC_TASK_NOCONNECT) {
1789                         rpc_exit(task, -ENOTCONN);
1790                         return;
1791                 }
1792                 xprt_connect(task);
1793         }
1794 }
1795
1796 /*
1797  * 4c.  Sort out connect result
1798  */
1799 static void
1800 call_connect_status(struct rpc_task *task)
1801 {
1802         struct rpc_clnt *clnt = task->tk_client;
1803         int status = task->tk_status;
1804
1805         dprint_status(task);
1806
1807         trace_rpc_connect_status(task, status);
1808         task->tk_status = 0;
1809         switch (status) {
1810         case -ECONNREFUSED:
1811         case -ECONNRESET:
1812         case -ECONNABORTED:
1813         case -ENETUNREACH:
1814         case -EHOSTUNREACH:
1815                 if (RPC_IS_SOFTCONN(task))
1816                         break;
1817                 /* retry with existing socket, after a delay */
1818                 rpc_delay(task, 3*HZ);
1819         case -EAGAIN:
1820                 /* Check for timeouts before looping back to call_bind */
1821         case -ETIMEDOUT:
1822                 task->tk_action = call_timeout;
1823                 return;
1824         case 0:
1825                 clnt->cl_stats->netreconn++;
1826                 task->tk_action = call_transmit;
1827                 return;
1828         }
1829         rpc_exit(task, status);
1830 }
1831
1832 /*
1833  * 5.   Transmit the RPC request, and wait for reply
1834  */
1835 static void
1836 call_transmit(struct rpc_task *task)
1837 {
1838         int is_retrans = RPC_WAS_SENT(task);
1839
1840         dprint_status(task);
1841
1842         task->tk_action = call_status;
1843         if (task->tk_status < 0)
1844                 return;
1845         if (!xprt_prepare_transmit(task))
1846                 return;
1847         task->tk_action = call_transmit_status;
1848         /* Encode here so that rpcsec_gss can use correct sequence number. */
1849         if (rpc_task_need_encode(task)) {
1850                 rpc_xdr_encode(task);
1851                 /* Did the encode result in an error condition? */
1852                 if (task->tk_status != 0) {
1853                         /* Was the error nonfatal? */
1854                         if (task->tk_status == -EAGAIN)
1855                                 rpc_delay(task, HZ >> 4);
1856                         else
1857                                 rpc_exit(task, task->tk_status);
1858                         return;
1859                 }
1860         }
1861         xprt_transmit(task);
1862         if (task->tk_status < 0)
1863                 return;
1864         if (is_retrans)
1865                 task->tk_client->cl_stats->rpcretrans++;
1866         /*
1867          * On success, ensure that we call xprt_end_transmit() before sleeping
1868          * in order to allow access to the socket to other RPC requests.
1869          */
1870         call_transmit_status(task);
1871         if (rpc_reply_expected(task))
1872                 return;
1873         task->tk_action = rpc_exit_task;
1874         rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1875 }
1876
1877 /*
1878  * 5a.  Handle cleanup after a transmission
1879  */
1880 static void
1881 call_transmit_status(struct rpc_task *task)
1882 {
1883         task->tk_action = call_status;
1884
1885         /*
1886          * Common case: success.  Force the compiler to put this
1887          * test first.
1888          */
1889         if (task->tk_status == 0) {
1890                 xprt_end_transmit(task);
1891                 rpc_task_force_reencode(task);
1892                 return;
1893         }
1894
1895         switch (task->tk_status) {
1896         case -EAGAIN:
1897                 break;
1898         default:
1899                 dprint_status(task);
1900                 xprt_end_transmit(task);
1901                 rpc_task_force_reencode(task);
1902                 break;
1903                 /*
1904                  * Special cases: if we've been waiting on the
1905                  * socket's write_space() callback, or if the
1906                  * socket just returned a connection error,
1907                  * then hold onto the transport lock.
1908                  */
1909         case -ECONNREFUSED:
1910         case -EHOSTDOWN:
1911         case -EHOSTUNREACH:
1912         case -ENETUNREACH:
1913                 if (RPC_IS_SOFTCONN(task)) {
1914                         xprt_end_transmit(task);
1915                         rpc_exit(task, task->tk_status);
1916                         break;
1917                 }
1918         case -ECONNRESET:
1919         case -ECONNABORTED:
1920         case -ENOTCONN:
1921         case -EPIPE:
1922                 rpc_task_force_reencode(task);
1923         }
1924 }
1925
1926 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1927 /*
1928  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1929  * addition, disconnect on connectivity errors.
1930  */
1931 static void
1932 call_bc_transmit(struct rpc_task *task)
1933 {
1934         struct rpc_rqst *req = task->tk_rqstp;
1935
1936         if (!xprt_prepare_transmit(task)) {
1937                 /*
1938                  * Could not reserve the transport. Try again after the
1939                  * transport is released.
1940                  */
1941                 task->tk_status = 0;
1942                 task->tk_action = call_bc_transmit;
1943                 return;
1944         }
1945
1946         task->tk_action = rpc_exit_task;
1947         if (task->tk_status < 0) {
1948                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1949                         "error: %d\n", task->tk_status);
1950                 return;
1951         }
1952
1953         xprt_transmit(task);
1954         xprt_end_transmit(task);
1955         dprint_status(task);
1956         switch (task->tk_status) {
1957         case 0:
1958                 /* Success */
1959                 break;
1960         case -EHOSTDOWN:
1961         case -EHOSTUNREACH:
1962         case -ENETUNREACH:
1963         case -ETIMEDOUT:
1964                 /*
1965                  * Problem reaching the server.  Disconnect and let the
1966                  * forechannel reestablish the connection.  The server will
1967                  * have to retransmit the backchannel request and we'll
1968                  * reprocess it.  Since these ops are idempotent, there's no
1969                  * need to cache our reply at this time.
1970                  */
1971                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1972                         "error: %d\n", task->tk_status);
1973                 xprt_conditional_disconnect(req->rq_xprt,
1974                         req->rq_connect_cookie);
1975                 break;
1976         default:
1977                 /*
1978                  * We were unable to reply and will have to drop the
1979                  * request.  The server should reconnect and retransmit.
1980                  */
1981                 WARN_ON_ONCE(task->tk_status == -EAGAIN);
1982                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1983                         "error: %d\n", task->tk_status);
1984                 break;
1985         }
1986         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1987 }
1988 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1989
1990 /*
1991  * 6.   Sort out the RPC call status
1992  */
1993 static void
1994 call_status(struct rpc_task *task)
1995 {
1996         struct rpc_clnt *clnt = task->tk_client;
1997         struct rpc_rqst *req = task->tk_rqstp;
1998         int             status;
1999
2000         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
2001                 task->tk_status = req->rq_reply_bytes_recvd;
2002
2003         dprint_status(task);
2004
2005         status = task->tk_status;
2006         if (status >= 0) {
2007                 task->tk_action = call_decode;
2008                 return;
2009         }
2010
2011         trace_rpc_call_status(task);
2012         task->tk_status = 0;
2013         switch(status) {
2014         case -EHOSTDOWN:
2015         case -EHOSTUNREACH:
2016         case -ENETUNREACH:
2017                 if (RPC_IS_SOFTCONN(task)) {
2018                         rpc_exit(task, status);
2019                         break;
2020                 }
2021                 /*
2022                  * Delay any retries for 3 seconds, then handle as if it
2023                  * were a timeout.
2024                  */
2025                 rpc_delay(task, 3*HZ);
2026         case -ETIMEDOUT:
2027                 task->tk_action = call_timeout;
2028                 if (!(task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT)
2029                     && task->tk_client->cl_discrtry)
2030                         xprt_conditional_disconnect(req->rq_xprt,
2031                                         req->rq_connect_cookie);
2032                 break;
2033         case -ECONNREFUSED:
2034         case -ECONNRESET:
2035         case -ECONNABORTED:
2036                 rpc_force_rebind(clnt);
2037                 rpc_delay(task, 3*HZ);
2038         case -EPIPE:
2039         case -ENOTCONN:
2040                 task->tk_action = call_bind;
2041                 break;
2042         case -EAGAIN:
2043                 task->tk_action = call_transmit;
2044                 break;
2045         case -EIO:
2046                 /* shutdown or soft timeout */
2047                 rpc_exit(task, status);
2048                 break;
2049         default:
2050                 if (clnt->cl_chatty)
2051                         printk("%s: RPC call returned error %d\n",
2052                                clnt->cl_program->name, -status);
2053                 rpc_exit(task, status);
2054         }
2055 }
2056
2057 /*
2058  * 6a.  Handle RPC timeout
2059  *      We do not release the request slot, so we keep using the
2060  *      same XID for all retransmits.
2061  */
2062 static void
2063 call_timeout(struct rpc_task *task)
2064 {
2065         struct rpc_clnt *clnt = task->tk_client;
2066
2067         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
2068                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
2069                 goto retry;
2070         }
2071
2072         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
2073         task->tk_timeouts++;
2074
2075         if (RPC_IS_SOFTCONN(task)) {
2076                 rpc_exit(task, -ETIMEDOUT);
2077                 return;
2078         }
2079         if (RPC_IS_SOFT(task)) {
2080                 if (clnt->cl_chatty) {
2081                         rcu_read_lock();
2082                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
2083                                 clnt->cl_program->name,
2084                                 rcu_dereference(clnt->cl_xprt)->servername);
2085                         rcu_read_unlock();
2086                 }
2087                 if (task->tk_flags & RPC_TASK_TIMEOUT)
2088                         rpc_exit(task, -ETIMEDOUT);
2089                 else
2090                         rpc_exit(task, -EIO);
2091                 return;
2092         }
2093
2094         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
2095                 task->tk_flags |= RPC_CALL_MAJORSEEN;
2096                 if (clnt->cl_chatty) {
2097                         rcu_read_lock();
2098                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
2099                         clnt->cl_program->name,
2100                         rcu_dereference(clnt->cl_xprt)->servername);
2101                         rcu_read_unlock();
2102                 }
2103         }
2104         rpc_force_rebind(clnt);
2105         /*
2106          * Did our request time out due to an RPCSEC_GSS out-of-sequence
2107          * event? RFC2203 requires the server to drop all such requests.
2108          */
2109         rpcauth_invalcred(task);
2110
2111 retry:
2112         task->tk_action = call_bind;
2113         task->tk_status = 0;
2114 }
2115
2116 /*
2117  * 7.   Decode the RPC reply
2118  */
2119 static void
2120 call_decode(struct rpc_task *task)
2121 {
2122         struct rpc_clnt *clnt = task->tk_client;
2123         struct rpc_rqst *req = task->tk_rqstp;
2124         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
2125         __be32          *p;
2126
2127         dprint_status(task);
2128
2129         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
2130                 if (clnt->cl_chatty) {
2131                         rcu_read_lock();
2132                         printk(KERN_NOTICE "%s: server %s OK\n",
2133                                 clnt->cl_program->name,
2134                                 rcu_dereference(clnt->cl_xprt)->servername);
2135                         rcu_read_unlock();
2136                 }
2137                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
2138         }
2139
2140         /*
2141          * Ensure that we see all writes made by xprt_complete_rqst()
2142          * before it changed req->rq_reply_bytes_recvd.
2143          */
2144         smp_rmb();
2145         req->rq_rcv_buf.len = req->rq_private_buf.len;
2146
2147         /* Check that the softirq receive buffer is valid */
2148         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
2149                                 sizeof(req->rq_rcv_buf)) != 0);
2150
2151         if (req->rq_rcv_buf.len < 12) {
2152                 if (!RPC_IS_SOFT(task)) {
2153                         task->tk_action = call_bind;
2154                         goto out_retry;
2155                 }
2156                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2157                                 clnt->cl_program->name, task->tk_status);
2158                 task->tk_action = call_timeout;
2159                 goto out_retry;
2160         }
2161
2162         p = rpc_verify_header(task);
2163         if (IS_ERR(p)) {
2164                 if (p == ERR_PTR(-EAGAIN))
2165                         goto out_retry;
2166                 return;
2167         }
2168
2169         task->tk_action = rpc_exit_task;
2170
2171         if (decode) {
2172                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2173                                                       task->tk_msg.rpc_resp);
2174         }
2175         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2176                         task->tk_status);
2177         return;
2178 out_retry:
2179         task->tk_status = 0;
2180         /* Note: rpc_verify_header() may have freed the RPC slot */
2181         if (task->tk_rqstp == req) {
2182                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2183                 if (task->tk_client->cl_discrtry)
2184                         xprt_conditional_disconnect(req->rq_xprt,
2185                                         req->rq_connect_cookie);
2186         }
2187 }
2188
2189 static __be32 *
2190 rpc_encode_header(struct rpc_task *task)
2191 {
2192         struct rpc_clnt *clnt = task->tk_client;
2193         struct rpc_rqst *req = task->tk_rqstp;
2194         __be32          *p = req->rq_svec[0].iov_base;
2195
2196         /* FIXME: check buffer size? */
2197
2198         p = xprt_skip_transport_header(req->rq_xprt, p);
2199         *p++ = req->rq_xid;             /* XID */
2200         *p++ = htonl(RPC_CALL);         /* CALL */
2201         *p++ = htonl(RPC_VERSION);      /* RPC version */
2202         *p++ = htonl(clnt->cl_prog);    /* program number */
2203         *p++ = htonl(clnt->cl_vers);    /* program version */
2204         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
2205         p = rpcauth_marshcred(task, p);
2206         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2207         return p;
2208 }
2209
2210 static __be32 *
2211 rpc_verify_header(struct rpc_task *task)
2212 {
2213         struct rpc_clnt *clnt = task->tk_client;
2214         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2215         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2216         __be32  *p = iov->iov_base;
2217         u32 n;
2218         int error = -EACCES;
2219
2220         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2221                 /* RFC-1014 says that the representation of XDR data must be a
2222                  * multiple of four bytes
2223                  * - if it isn't pointer subtraction in the NFS client may give
2224                  *   undefined results
2225                  */
2226                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
2227                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2228                        task->tk_rqstp->rq_rcv_buf.len);
2229                 error = -EIO;
2230                 goto out_err;
2231         }
2232         if ((len -= 3) < 0)
2233                 goto out_overflow;
2234
2235         p += 1; /* skip XID */
2236         if ((n = ntohl(*p++)) != RPC_REPLY) {
2237                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2238                         task->tk_pid, __func__, n);
2239                 error = -EIO;
2240                 goto out_garbage;
2241         }
2242
2243         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2244                 if (--len < 0)
2245                         goto out_overflow;
2246                 switch ((n = ntohl(*p++))) {
2247                 case RPC_AUTH_ERROR:
2248                         break;
2249                 case RPC_MISMATCH:
2250                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2251                                 task->tk_pid, __func__);
2252                         error = -EPROTONOSUPPORT;
2253                         goto out_err;
2254                 default:
2255                         dprintk("RPC: %5u %s: RPC call rejected, "
2256                                 "unknown error: %x\n",
2257                                 task->tk_pid, __func__, n);
2258                         error = -EIO;
2259                         goto out_err;
2260                 }
2261                 if (--len < 0)
2262                         goto out_overflow;
2263                 switch ((n = ntohl(*p++))) {
2264                 case RPC_AUTH_REJECTEDCRED:
2265                 case RPC_AUTH_REJECTEDVERF:
2266                 case RPCSEC_GSS_CREDPROBLEM:
2267                 case RPCSEC_GSS_CTXPROBLEM:
2268                         if (!task->tk_cred_retry)
2269                                 break;
2270                         task->tk_cred_retry--;
2271                         dprintk("RPC: %5u %s: retry stale creds\n",
2272                                         task->tk_pid, __func__);
2273                         rpcauth_invalcred(task);
2274                         /* Ensure we obtain a new XID! */
2275                         xprt_release(task);
2276                         task->tk_action = call_reserve;
2277                         goto out_retry;
2278                 case RPC_AUTH_BADCRED:
2279                 case RPC_AUTH_BADVERF:
2280                         /* possibly garbled cred/verf? */
2281                         if (!task->tk_garb_retry)
2282                                 break;
2283                         task->tk_garb_retry--;
2284                         dprintk("RPC: %5u %s: retry garbled creds\n",
2285                                         task->tk_pid, __func__);
2286                         task->tk_action = call_bind;
2287                         goto out_retry;
2288                 case RPC_AUTH_TOOWEAK:
2289                         rcu_read_lock();
2290                         printk(KERN_NOTICE "RPC: server %s requires stronger "
2291                                "authentication.\n",
2292                                rcu_dereference(clnt->cl_xprt)->servername);
2293                         rcu_read_unlock();
2294                         break;
2295                 default:
2296                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
2297                                         task->tk_pid, __func__, n);
2298                         error = -EIO;
2299                 }
2300                 dprintk("RPC: %5u %s: call rejected %d\n",
2301                                 task->tk_pid, __func__, n);
2302                 goto out_err;
2303         }
2304         p = rpcauth_checkverf(task, p);
2305         if (IS_ERR(p)) {
2306                 error = PTR_ERR(p);
2307                 dprintk("RPC: %5u %s: auth check failed with %d\n",
2308                                 task->tk_pid, __func__, error);
2309                 goto out_garbage;               /* bad verifier, retry */
2310         }
2311         len = p - (__be32 *)iov->iov_base - 1;
2312         if (len < 0)
2313                 goto out_overflow;
2314         switch ((n = ntohl(*p++))) {
2315         case RPC_SUCCESS:
2316                 return p;
2317         case RPC_PROG_UNAVAIL:
2318                 dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2319                                 "by server %s\n", task->tk_pid, __func__,
2320                                 (unsigned int)clnt->cl_prog,
2321                                 rcu_dereference(clnt->cl_xprt)->servername);
2322                 error = -EPFNOSUPPORT;
2323                 goto out_err;
2324         case RPC_PROG_MISMATCH:
2325                 dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2326                                 "by server %s\n", task->tk_pid, __func__,
2327                                 (unsigned int)clnt->cl_prog,
2328                                 (unsigned int)clnt->cl_vers,
2329                                 rcu_dereference(clnt->cl_xprt)->servername);
2330                 error = -EPROTONOSUPPORT;
2331                 goto out_err;
2332         case RPC_PROC_UNAVAIL:
2333                 dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2334                                 "version %u on server %s\n",
2335                                 task->tk_pid, __func__,
2336                                 rpc_proc_name(task),
2337                                 clnt->cl_prog, clnt->cl_vers,
2338                                 rcu_dereference(clnt->cl_xprt)->servername);
2339                 error = -EOPNOTSUPP;
2340                 goto out_err;
2341         case RPC_GARBAGE_ARGS:
2342                 dprintk("RPC: %5u %s: server saw garbage\n",
2343                                 task->tk_pid, __func__);
2344                 break;                  /* retry */
2345         default:
2346                 dprintk("RPC: %5u %s: server accept status: %x\n",
2347                                 task->tk_pid, __func__, n);
2348                 /* Also retry */
2349         }
2350
2351 out_garbage:
2352         clnt->cl_stats->rpcgarbage++;
2353         if (task->tk_garb_retry) {
2354                 task->tk_garb_retry--;
2355                 dprintk("RPC: %5u %s: retrying\n",
2356                                 task->tk_pid, __func__);
2357                 task->tk_action = call_bind;
2358 out_retry:
2359                 return ERR_PTR(-EAGAIN);
2360         }
2361 out_err:
2362         rpc_exit(task, error);
2363         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2364                         __func__, error);
2365         return ERR_PTR(error);
2366 out_overflow:
2367         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2368                         __func__);
2369         goto out_garbage;
2370 }
2371
2372 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2373 {
2374 }
2375
2376 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2377 {
2378         return 0;
2379 }
2380
2381 static struct rpc_procinfo rpcproc_null = {
2382         .p_encode = rpcproc_encode_null,
2383         .p_decode = rpcproc_decode_null,
2384 };
2385
2386 static int rpc_ping(struct rpc_clnt *clnt)
2387 {
2388         struct rpc_message msg = {
2389                 .rpc_proc = &rpcproc_null,
2390         };
2391         int err;
2392         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2393         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2394         put_rpccred(msg.rpc_cred);
2395         return err;
2396 }
2397
2398 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2399 {
2400         struct rpc_message msg = {
2401                 .rpc_proc = &rpcproc_null,
2402                 .rpc_cred = cred,
2403         };
2404         struct rpc_task_setup task_setup_data = {
2405                 .rpc_client = clnt,
2406                 .rpc_message = &msg,
2407                 .callback_ops = &rpc_default_ops,
2408                 .flags = flags,
2409         };
2410         return rpc_run_task(&task_setup_data);
2411 }
2412 EXPORT_SYMBOL_GPL(rpc_call_null);
2413
2414 #ifdef RPC_DEBUG
2415 static void rpc_show_header(void)
2416 {
2417         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2418                 "-timeout ---ops--\n");
2419 }
2420
2421 static void rpc_show_task(const struct rpc_clnt *clnt,
2422                           const struct rpc_task *task)
2423 {
2424         const char *rpc_waitq = "none";
2425
2426         if (RPC_IS_QUEUED(task))
2427                 rpc_waitq = rpc_qname(task->tk_waitqueue);
2428
2429         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2430                 task->tk_pid, task->tk_flags, task->tk_status,
2431                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2432                 clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
2433                 task->tk_action, rpc_waitq);
2434 }
2435
2436 void rpc_show_tasks(struct net *net)
2437 {
2438         struct rpc_clnt *clnt;
2439         struct rpc_task *task;
2440         int header = 0;
2441         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2442
2443         spin_lock(&sn->rpc_client_lock);
2444         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2445                 spin_lock(&clnt->cl_lock);
2446                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2447                         if (!header) {
2448                                 rpc_show_header();
2449                                 header++;
2450                         }
2451                         rpc_show_task(clnt, task);
2452                 }
2453                 spin_unlock(&clnt->cl_lock);
2454         }
2455         spin_unlock(&sn->rpc_client_lock);
2456 }
2457 #endif