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 <[email protected]>
  17  *  Copyright (C) 1995,1996 Olaf Kirch <[email protected]>
  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 #if IS_ENABLED(CONFIG_SUNRPC_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 = strlcpy(clnt->cl_nodename,
 290                         nodename, sizeof(clnt->cl_nodename));
 291 }
 292
 293 static int rpc_client_register(struct rpc_clnt *clnt,
 294                                rpc_authflavor_t pseudoflavor,
 295                                const char *client_name)
 296 {
 297         struct rpc_auth_create_args auth_args = {
 298                 .pseudoflavor = pseudoflavor,
 299                 .target_name = client_name,
 300         };
 301         struct rpc_auth *auth;
 302         struct net *net = rpc_net_ns(clnt);
 303         struct super_block *pipefs_sb;
 304         int err;
 305
 306         err = rpc_clnt_debugfs_register(clnt);
 307         if (err)
 308                 return err;
 309
 310         pipefs_sb = rpc_get_sb_net(net);
 311         if (pipefs_sb) {
 312                 err = rpc_setup_pipedir(pipefs_sb, clnt);
 313                 if (err)
 314                         goto out;
 315         }
 316
 317         rpc_register_client(clnt);
 318         if (pipefs_sb)
 319                 rpc_put_sb_net(net);
 320
 321         auth = rpcauth_create(&auth_args, clnt);
 322         if (IS_ERR(auth)) {
 323                 dprintk("RPC:       Couldn't create auth handle (flavor %u)\n",
 324                                 pseudoflavor);
 325                 err = PTR_ERR(auth);
 326                 goto err_auth;
 327         }
 328         return 0;
 329 err_auth:
 330         pipefs_sb = rpc_get_sb_net(net);
 331         rpc_unregister_client(clnt);
 332         __rpc_clnt_remove_pipedir(clnt);
 333 out:
 334         if (pipefs_sb)
 335                 rpc_put_sb_net(net);
 336         rpc_clnt_debugfs_unregister(clnt);
 337         return err;
 338 }
 339
 340 static DEFINE_IDA(rpc_clids);
 341
 342 static int rpc_alloc_clid(struct rpc_clnt *clnt)
 343 {
 344         int clid;
 345
 346         clid = ida_simple_get(&rpc_clids, 0, 0, GFP_KERNEL);
 347         if (clid < 0)
 348                 return clid;
 349         clnt->cl_clid = clid;
 350         return 0;
 351 }
 352
 353 static void rpc_free_clid(struct rpc_clnt *clnt)
 354 {
 355         ida_simple_remove(&rpc_clids, clnt->cl_clid);
 356 }
 357
 358 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args,
 359                 struct rpc_xprt *xprt,
 360                 struct rpc_clnt *parent)
 361 {
 362         const struct rpc_program *program = args->program;
 363         const struct rpc_version *version;
 364         struct rpc_clnt *clnt = NULL;
 365         const struct rpc_timeout *timeout;
 366         const char *nodename = args->nodename;
 367         int err;
 368
 369         /* sanity check the name before trying to print it */
 370         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 371                         program->name, args->servername, xprt);
 372
 373         err = rpciod_up();
 374         if (err)
 375                 goto out_no_rpciod;
 376
 377         err = -EINVAL;
 378         if (args->version >= program->nrvers)
 379                 goto out_err;
 380         version = program->version[args->version];
 381         if (version == NULL)
 382                 goto out_err;
 383
 384         err = -ENOMEM;
 385         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 386         if (!clnt)
 387                 goto out_err;
 388         clnt->cl_parent = parent ? : clnt;
 389
 390         err = rpc_alloc_clid(clnt);
 391         if (err)
 392                 goto out_no_clid;
 393
 394         clnt->cl_procinfo = version->procs;
 395         clnt->cl_maxproc  = version->nrprocs;
 396         clnt->cl_prog     = args->prognumber ? : program->number;
 397         clnt->cl_vers     = version->number;
 398         clnt->cl_stats    = program->stats;
 399         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 400         rpc_init_pipe_dir_head(&clnt->cl_pipedir_objects);
 401         err = -ENOMEM;
 402         if (clnt->cl_metrics == NULL)
 403                 goto out_no_stats;
 404         clnt->cl_program  = program;
 405         INIT_LIST_HEAD(&clnt->cl_tasks);
 406         spin_lock_init(&clnt->cl_lock);
 407
 408         timeout = xprt->timeout;
 409         if (args->timeout != NULL) {
 410                 memcpy(&clnt->cl_timeout_default, args->timeout,
 411                                 sizeof(clnt->cl_timeout_default));
 412                 timeout = &clnt->cl_timeout_default;
 413         }
 414
 415         rpc_clnt_set_transport(clnt, xprt, timeout);
 416
 417         clnt->cl_rtt = &clnt->cl_rtt_default;
 418         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
 419
 420         atomic_set(&clnt->cl_count, 1);
 421
 422         if (nodename == NULL)
 423                 nodename = utsname()->nodename;
 424         /* save the nodename */
 425         rpc_clnt_set_nodename(clnt, nodename);
 426
 427         err = rpc_client_register(clnt, args->authflavor, args->client_name);
 428         if (err)
 429                 goto out_no_path;
 430         if (parent)
 431                 atomic_inc(&parent->cl_count);
 432         return clnt;
 433
 434 out_no_path:
 435         rpc_free_iostats(clnt->cl_metrics);
 436 out_no_stats:
 437         rpc_free_clid(clnt);
 438 out_no_clid:
 439         kfree(clnt);
 440 out_err:
 441         rpciod_down();
 442 out_no_rpciod:
 443         xprt_put(xprt);
 444         return ERR_PTR(err);
 445 }
 446
 447 struct rpc_clnt *rpc_create_xprt(struct rpc_create_args *args,
 448                                         struct rpc_xprt *xprt)
 449 {
 450         struct rpc_clnt *clnt = NULL;
 451
 452         clnt = rpc_new_client(args, xprt, NULL);
 453         if (IS_ERR(clnt))
 454                 return clnt;
 455
 456         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 457                 int err = rpc_ping(clnt);
 458                 if (err != 0) {
 459                         rpc_shutdown_client(clnt);
 460                         return ERR_PTR(err);
 461                 }
 462         }
 463
 464         clnt->cl_softrtry = 1;
 465         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 466                 clnt->cl_softrtry = 0;
 467
 468         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 469                 clnt->cl_autobind = 1;
 470         if (args->flags & RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT)
 471                 clnt->cl_noretranstimeo = 1;
 472         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 473                 clnt->cl_discrtry = 1;
 474         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 475                 clnt->cl_chatty = 1;
 476
 477         return clnt;
 478 }
 479 EXPORT_SYMBOL_GPL(rpc_create_xprt);
 480
 481 /**
 482  * rpc_create - create an RPC client and transport with one call
 483  * @args: rpc_clnt create argument structure
 484  *
 485  * Creates and initializes an RPC transport and an RPC client.
 486  *
 487  * It can ping the server in order to determine if it is up, and to see if
 488  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 489  * this behavior so asynchronous tasks can also use rpc_create.
 490  */
 491 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 492 {
 493         struct rpc_xprt *xprt;
 494         struct xprt_create xprtargs = {
 495                 .net = args->net,
 496                 .ident = args->protocol,
 497                 .srcaddr = args->saddress,
 498                 .dstaddr = args->address,
 499                 .addrlen = args->addrsize,
 500                 .servername = args->servername,
 501                 .bc_xprt = args->bc_xprt,
 502         };
 503         char servername[48];
 504
 505         if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
 506                 xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
 507         if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
 508                 xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
 509         /*
 510          * If the caller chooses not to specify a hostname, whip
 511          * up a string representation of the passed-in address.
 512          */
 513         if (xprtargs.servername == NULL) {
 514                 struct sockaddr_un *sun =
 515                                 (struct sockaddr_un *)args->address;
 516                 struct sockaddr_in *sin =
 517                                 (struct sockaddr_in *)args->address;
 518                 struct sockaddr_in6 *sin6 =
 519                                 (struct sockaddr_in6 *)args->address;
 520
 521                 servername[0] = '\0';
 522                 switch (args->address->sa_family) {
 523                 case AF_LOCAL:
 524                         snprintf(servername, sizeof(servername), "%s",
 525                                  sun->sun_path);
 526                         break;
 527                 case AF_INET:
 528                         snprintf(servername, sizeof(servername), "%pI4",
 529                                  &sin->sin_addr.s_addr);
 530                         break;
 531                 case AF_INET6:
 532                         snprintf(servername, sizeof(servername), "%pI6",
 533                                  &sin6->sin6_addr);
 534                         break;
 535                 default:
 536                         /* caller wants default server name, but
 537                          * address family isn't recognized. */
 538                         return ERR_PTR(-EINVAL);
 539                 }
 540                 xprtargs.servername = servername;
 541         }
 542
 543         xprt = xprt_create_transport(&xprtargs);
 544         if (IS_ERR(xprt))
 545                 return (struct rpc_clnt *)xprt;
 546
 547         /*
 548          * By default, kernel RPC client connects from a reserved port.
 549          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 550          * but it is always enabled for rpciod, which handles the connect
 551          * operation.
 552          */
 553         xprt->resvport = 1;
 554         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 555                 xprt->resvport = 0;
 556
 557         return rpc_create_xprt(args, xprt);
 558 }
 559 EXPORT_SYMBOL_GPL(rpc_create);
 560
 561 /*
 562  * This function clones the RPC client structure. It allows us to share the
 563  * same transport while varying parameters such as the authentication
 564  * flavour.
 565  */
 566 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
 567                                            struct rpc_clnt *clnt)
 568 {
 569         struct rpc_xprt *xprt;
 570         struct rpc_clnt *new;
 571         int err;
 572
 573         err = -ENOMEM;
 574         rcu_read_lock();
 575         xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
 576         rcu_read_unlock();
 577         if (xprt == NULL)
 578                 goto out_err;
 579         args->servername = xprt->servername;
 580         args->nodename = clnt->cl_nodename;
 581
 582         new = rpc_new_client(args, xprt, clnt);
 583         if (IS_ERR(new)) {
 584                 err = PTR_ERR(new);
 585                 goto out_err;
 586         }
 587
 588         /* Turn off autobind on clones */
 589         new->cl_autobind = 0;
 590         new->cl_softrtry = clnt->cl_softrtry;
 591         new->cl_noretranstimeo = clnt->cl_noretranstimeo;
 592         new->cl_discrtry = clnt->cl_discrtry;
 593         new->cl_chatty = clnt->cl_chatty;
 594         return new;
 595
 596 out_err:
 597         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 598         return ERR_PTR(err);
 599 }
 600
 601 /**
 602  * rpc_clone_client - Clone an RPC client structure
 603  *
 604  * @clnt: RPC client whose parameters are copied
 605  *
 606  * Returns a fresh RPC client or an ERR_PTR.
 607  */
 608 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
 609 {
 610         struct rpc_create_args args = {
 611                 .program        = clnt->cl_program,
 612                 .prognumber     = clnt->cl_prog,
 613                 .version        = clnt->cl_vers,
 614                 .authflavor     = clnt->cl_auth->au_flavor,
 615         };
 616         return __rpc_clone_client(&args, clnt);
 617 }
 618 EXPORT_SYMBOL_GPL(rpc_clone_client);
 619
 620 /**
 621  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
 622  *
 623  * @clnt: RPC client whose parameters are copied
 624  * @flavor: security flavor for new client
 625  *
 626  * Returns a fresh RPC client or an ERR_PTR.
 627  */
 628 struct rpc_clnt *
 629 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
 630 {
 631         struct rpc_create_args args = {
 632                 .program        = clnt->cl_program,
 633                 .prognumber     = clnt->cl_prog,
 634                 .version        = clnt->cl_vers,
 635                 .authflavor     = flavor,
 636         };
 637         return __rpc_clone_client(&args, clnt);
 638 }
 639 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
 640
 641 /**
 642  * rpc_switch_client_transport: switch the RPC transport on the fly
 643  * @clnt: pointer to a struct rpc_clnt
 644  * @args: pointer to the new transport arguments
 645  * @timeout: pointer to the new timeout parameters
 646  *
 647  * This function allows the caller to switch the RPC transport for the
 648  * rpc_clnt structure 'clnt' to allow it to connect to a mirrored NFS
 649  * server, for instance.  It assumes that the caller has ensured that
 650  * there are no active RPC tasks by using some form of locking.
 651  *
 652  * Returns zero if "clnt" is now using the new xprt.  Otherwise a
 653  * negative errno is returned, and "clnt" continues to use the old
 654  * xprt.
 655  */
 656 int rpc_switch_client_transport(struct rpc_clnt *clnt,
 657                 struct xprt_create *args,
 658                 const struct rpc_timeout *timeout)
 659 {
 660         const struct rpc_timeout *old_timeo;
 661         rpc_authflavor_t pseudoflavor;
 662         struct rpc_xprt *xprt, *old;
 663         struct rpc_clnt *parent;
 664         int err;
 665
 666         xprt = xprt_create_transport(args);
 667         if (IS_ERR(xprt)) {
 668                 dprintk("RPC:       failed to create new xprt for clnt %p\n",
 669                         clnt);
 670                 return PTR_ERR(xprt);
 671         }
 672
 673         pseudoflavor = clnt->cl_auth->au_flavor;
 674
 675         old_timeo = clnt->cl_timeout;
 676         old = rpc_clnt_set_transport(clnt, xprt, timeout);
 677
 678         rpc_unregister_client(clnt);
 679         __rpc_clnt_remove_pipedir(clnt);
 680         rpc_clnt_debugfs_unregister(clnt);
 681
 682         /*
 683          * A new transport was created.  "clnt" therefore
 684          * becomes the root of a new cl_parent tree.  clnt's
 685          * children, if it has any, still point to the old xprt.
 686          */
 687         parent = clnt->cl_parent;
 688         clnt->cl_parent = clnt;
 689
 690         /*
 691          * The old rpc_auth cache cannot be re-used.  GSS
 692          * contexts in particular are between a single
 693          * client and server.
 694          */
 695         err = rpc_client_register(clnt, pseudoflavor, NULL);
 696         if (err)
 697                 goto out_revert;
 698
 699         synchronize_rcu();
 700         if (parent != clnt)
 701                 rpc_release_client(parent);
 702         xprt_put(old);
 703         dprintk("RPC:       replaced xprt for clnt %p\n", clnt);
 704         return 0;
 705
 706 out_revert:
 707         rpc_clnt_set_transport(clnt, old, old_timeo);
 708         clnt->cl_parent = parent;
 709         rpc_client_register(clnt, pseudoflavor, NULL);
 710         xprt_put(xprt);
 711         dprintk("RPC:       failed to switch xprt for clnt %p\n", clnt);
 712         return err;
 713 }
 714 EXPORT_SYMBOL_GPL(rpc_switch_client_transport);
 715
 716 /*
 717  * Kill all tasks for the given client.
 718  * XXX: kill their descendants as well?
 719  */
 720 void rpc_killall_tasks(struct rpc_clnt *clnt)
 721 {
 722         struct rpc_task *rovr;
 723
 724
 725         if (list_empty(&clnt->cl_tasks))
 726                 return;
 727         dprintk("RPC:       killing all tasks for client %p\n", clnt);
 728         /*
 729          * Spin lock all_tasks to prevent changes...
 730          */
 731         spin_lock(&clnt->cl_lock);
 732         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
 733                 if (!RPC_IS_ACTIVATED(rovr))
 734                         continue;
 735                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
 736                         rovr->tk_flags |= RPC_TASK_KILLED;
 737                         rpc_exit(rovr, -EIO);
 738                         if (RPC_IS_QUEUED(rovr))
 739                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
 740                                                         rovr);
 741                 }
 742         }
 743         spin_unlock(&clnt->cl_lock);
 744 }
 745 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
 746
 747 /*
 748  * Properly shut down an RPC client, terminating all outstanding
 749  * requests.
 750  */
 751 void rpc_shutdown_client(struct rpc_clnt *clnt)
 752 {
 753         might_sleep();
 754
 755         dprintk_rcu("RPC:       shutting down %s client for %s\n",
 756                         clnt->cl_program->name,
 757                         rcu_dereference(clnt->cl_xprt)->servername);
 758
 759         while (!list_empty(&clnt->cl_tasks)) {
 760                 rpc_killall_tasks(clnt);
 761                 wait_event_timeout(destroy_wait,
 762                         list_empty(&clnt->cl_tasks), 1*HZ);
 763         }
 764
 765         rpc_release_client(clnt);
 766 }
 767 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 768
 769 /*
 770  * Free an RPC client
 771  */
 772 static struct rpc_clnt *
 773 rpc_free_client(struct rpc_clnt *clnt)
 774 {
 775         struct rpc_clnt *parent = NULL;
 776
 777         dprintk_rcu("RPC:       destroying %s client for %s\n",
 778                         clnt->cl_program->name,
 779                         rcu_dereference(clnt->cl_xprt)->servername);
 780         if (clnt->cl_parent != clnt)
 781                 parent = clnt->cl_parent;
 782         rpc_clnt_debugfs_unregister(clnt);
 783         rpc_clnt_remove_pipedir(clnt);
 784         rpc_unregister_client(clnt);
 785         rpc_free_iostats(clnt->cl_metrics);
 786         clnt->cl_metrics = NULL;
 787         xprt_put(rcu_dereference_raw(clnt->cl_xprt));
 788         rpciod_down();
 789         rpc_free_clid(clnt);
 790         kfree(clnt);
 791         return parent;
 792 }
 793
 794 /*
 795  * Free an RPC client
 796  */
 797 static struct rpc_clnt *
 798 rpc_free_auth(struct rpc_clnt *clnt)
 799 {
 800         if (clnt->cl_auth == NULL)
 801                 return rpc_free_client(clnt);
 802
 803         /*
 804          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 805          *       release remaining GSS contexts. This mechanism ensures
 806          *       that it can do so safely.
 807          */
 808         atomic_inc(&clnt->cl_count);
 809         rpcauth_release(clnt->cl_auth);
 810         clnt->cl_auth = NULL;
 811         if (atomic_dec_and_test(&clnt->cl_count))
 812                 return rpc_free_client(clnt);
 813         return NULL;
 814 }
 815
 816 /*
 817  * Release reference to the RPC client
 818  */
 819 void
 820 rpc_release_client(struct rpc_clnt *clnt)
 821 {
 822         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 823
 824         do {
 825                 if (list_empty(&clnt->cl_tasks))
 826                         wake_up(&destroy_wait);
 827                 if (!atomic_dec_and_test(&clnt->cl_count))
 828                         break;
 829                 clnt = rpc_free_auth(clnt);
 830         } while (clnt != NULL);
 831 }
 832 EXPORT_SYMBOL_GPL(rpc_release_client);
 833
 834 /**
 835  * rpc_bind_new_program - bind a new RPC program to an existing client
 836  * @old: old rpc_client
 837  * @program: rpc program to set
 838  * @vers: rpc program version
 839  *
 840  * Clones the rpc client and sets up a new RPC program. This is mainly
 841  * of use for enabling different RPC programs to share the same transport.
 842  * The Sun NFSv2/v3 ACL protocol can do this.
 843  */
 844 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 845                                       const struct rpc_program *program,
 846                                       u32 vers)
 847 {
 848         struct rpc_create_args args = {
 849                 .program        = program,
 850                 .prognumber     = program->number,
 851                 .version        = vers,
 852                 .authflavor     = old->cl_auth->au_flavor,
 853         };
 854         struct rpc_clnt *clnt;
 855         int err;
 856
 857         clnt = __rpc_clone_client(&args, old);
 858         if (IS_ERR(clnt))
 859                 goto out;
 860         err = rpc_ping(clnt);
 861         if (err != 0) {
 862                 rpc_shutdown_client(clnt);
 863                 clnt = ERR_PTR(err);
 864         }
 865 out:
 866         return clnt;
 867 }
 868 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 869
 870 void rpc_task_release_client(struct rpc_task *task)
 871 {
 872         struct rpc_clnt *clnt = task->tk_client;
 873
 874         if (clnt != NULL) {
 875                 /* Remove from client task list */
 876                 spin_lock(&clnt->cl_lock);
 877                 list_del(&task->tk_task);
 878                 spin_unlock(&clnt->cl_lock);
 879                 task->tk_client = NULL;
 880
 881                 rpc_release_client(clnt);
 882         }
 883 }
 884
 885 static
 886 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
 887 {
 888         if (clnt != NULL) {
 889                 rpc_task_release_client(task);
 890                 task->tk_client = clnt;
 891                 atomic_inc(&clnt->cl_count);
 892                 if (clnt->cl_softrtry)
 893                         task->tk_flags |= RPC_TASK_SOFT;
 894                 if (clnt->cl_noretranstimeo)
 895                         task->tk_flags |= RPC_TASK_NO_RETRANS_TIMEOUT;
 896                 if (sk_memalloc_socks()) {
 897                         struct rpc_xprt *xprt;
 898
 899                         rcu_read_lock();
 900                         xprt = rcu_dereference(clnt->cl_xprt);
 901                         if (xprt->swapper)
 902                                 task->tk_flags |= RPC_TASK_SWAPPER;
 903                         rcu_read_unlock();
 904                 }
 905                 /* Add to the client's list of all tasks */
 906                 spin_lock(&clnt->cl_lock);
 907                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
 908                 spin_unlock(&clnt->cl_lock);
 909         }
 910 }
 911
 912 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
 913 {
 914         rpc_task_release_client(task);
 915         rpc_task_set_client(task, clnt);
 916 }
 917 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
 918
 919
 920 static void
 921 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
 922 {
 923         if (msg != NULL) {
 924                 task->tk_msg.rpc_proc = msg->rpc_proc;
 925                 task->tk_msg.rpc_argp = msg->rpc_argp;
 926                 task->tk_msg.rpc_resp = msg->rpc_resp;
 927                 if (msg->rpc_cred != NULL)
 928                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
 929         }
 930 }
 931
 932 /*
 933  * Default callback for async RPC calls
 934  */
 935 static void
 936 rpc_default_callback(struct rpc_task *task, void *data)
 937 {
 938 }
 939
 940 static const struct rpc_call_ops rpc_default_ops = {
 941         .rpc_call_done = rpc_default_callback,
 942 };
 943
 944 /**
 945  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 946  * @task_setup_data: pointer to task initialisation data
 947  */
 948 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 949 {
 950         struct rpc_task *task;
 951
 952         task = rpc_new_task(task_setup_data);
 953         if (IS_ERR(task))
 954                 goto out;
 955
 956         rpc_task_set_client(task, task_setup_data->rpc_client);
 957         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
 958
 959         if (task->tk_action == NULL)
 960                 rpc_call_start(task);
 961
 962         atomic_inc(&task->tk_count);
 963         rpc_execute(task);
 964 out:
 965         return task;
 966 }
 967 EXPORT_SYMBOL_GPL(rpc_run_task);
 968
 969 /**
 970  * rpc_call_sync - Perform a synchronous RPC call
 971  * @clnt: pointer to RPC client
 972  * @msg: RPC call parameters
 973  * @flags: RPC call flags
 974  */
 975 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 976 {
 977         struct rpc_task *task;
 978         struct rpc_task_setup task_setup_data = {
 979                 .rpc_client = clnt,
 980                 .rpc_message = msg,
 981                 .callback_ops = &rpc_default_ops,
 982                 .flags = flags,
 983         };
 984         int status;
 985
 986         WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
 987         if (flags & RPC_TASK_ASYNC) {
 988                 rpc_release_calldata(task_setup_data.callback_ops,
 989                         task_setup_data.callback_data);
 990                 return -EINVAL;
 991         }
 992
 993         task = rpc_run_task(&task_setup_data);
 994         if (IS_ERR(task))
 995                 return PTR_ERR(task);
 996         status = task->tk_status;
 997         rpc_put_task(task);
 998         return status;
 999 }
1000 EXPORT_SYMBOL_GPL(rpc_call_sync);
1001
1002 /**
1003  * rpc_call_async - Perform an asynchronous RPC call
1004  * @clnt: pointer to RPC client
1005  * @msg: RPC call parameters
1006  * @flags: RPC call flags
1007  * @tk_ops: RPC call ops
1008  * @data: user call data
1009  */
1010 int
1011 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
1012                const struct rpc_call_ops *tk_ops, void *data)
1013 {
1014         struct rpc_task *task;
1015         struct rpc_task_setup task_setup_data = {
1016                 .rpc_client = clnt,
1017                 .rpc_message = msg,
1018                 .callback_ops = tk_ops,
1019                 .callback_data = data,
1020                 .flags = flags|RPC_TASK_ASYNC,
1021         };
1022
1023         task = rpc_run_task(&task_setup_data);
1024         if (IS_ERR(task))
1025                 return PTR_ERR(task);
1026         rpc_put_task(task);
1027         return 0;
1028 }
1029 EXPORT_SYMBOL_GPL(rpc_call_async);
1030
1031 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1032 /**
1033  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
1034  * rpc_execute against it
1035  * @req: RPC request
1036  * @tk_ops: RPC call ops
1037  */
1038 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
1039                                 const struct rpc_call_ops *tk_ops)
1040 {
1041         struct rpc_task *task;
1042         struct xdr_buf *xbufp = &req->rq_snd_buf;
1043         struct rpc_task_setup task_setup_data = {
1044                 .callback_ops = tk_ops,
1045         };
1046
1047         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
1048         /*
1049          * Create an rpc_task to send the data
1050          */
1051         task = rpc_new_task(&task_setup_data);
1052         if (IS_ERR(task)) {
1053                 xprt_free_bc_request(req);
1054                 goto out;
1055         }
1056         task->tk_rqstp = req;
1057
1058         /*
1059          * Set up the xdr_buf length.
1060          * This also indicates that the buffer is XDR encoded already.
1061          */
1062         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
1063                         xbufp->tail[0].iov_len;
1064
1065         task->tk_action = call_bc_transmit;
1066         atomic_inc(&task->tk_count);
1067         WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
1068         rpc_execute(task);
1069
1070 out:
1071         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
1072         return task;
1073 }
1074 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1075
1076 void
1077 rpc_call_start(struct rpc_task *task)
1078 {
1079         task->tk_action = call_start;
1080 }
1081 EXPORT_SYMBOL_GPL(rpc_call_start);
1082
1083 /**
1084  * rpc_peeraddr - extract remote peer address from clnt's xprt
1085  * @clnt: RPC client structure
1086  * @buf: target buffer
1087  * @bufsize: length of target buffer
1088  *
1089  * Returns the number of bytes that are actually in the stored address.
1090  */
1091 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
1092 {
1093         size_t bytes;
1094         struct rpc_xprt *xprt;
1095
1096         rcu_read_lock();
1097         xprt = rcu_dereference(clnt->cl_xprt);
1098
1099         bytes = xprt->addrlen;
1100         if (bytes > bufsize)
1101                 bytes = bufsize;
1102         memcpy(buf, &xprt->addr, bytes);
1103         rcu_read_unlock();
1104
1105         return bytes;
1106 }
1107 EXPORT_SYMBOL_GPL(rpc_peeraddr);
1108
1109 /**
1110  * rpc_peeraddr2str - return remote peer address in printable format
1111  * @clnt: RPC client structure
1112  * @format: address format
1113  *
1114  * NB: the lifetime of the memory referenced by the returned pointer is
1115  * the same as the rpc_xprt itself.  As long as the caller uses this
1116  * pointer, it must hold the RCU read lock.
1117  */
1118 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
1119                              enum rpc_display_format_t format)
1120 {
1121         struct rpc_xprt *xprt;
1122
1123         xprt = rcu_dereference(clnt->cl_xprt);
1124
1125         if (xprt->address_strings[format] != NULL)
1126                 return xprt->address_strings[format];
1127         else
1128                 return "unprintable";
1129 }
1130 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
1131
1132 static const struct sockaddr_in rpc_inaddr_loopback = {
1133         .sin_family             = AF_INET,
1134         .sin_addr.s_addr        = htonl(INADDR_ANY),
1135 };
1136
1137 static const struct sockaddr_in6 rpc_in6addr_loopback = {
1138         .sin6_family            = AF_INET6,
1139         .sin6_addr              = IN6ADDR_ANY_INIT,
1140 };
1141
1142 /*
1143  * Try a getsockname() on a connected datagram socket.  Using a
1144  * connected datagram socket prevents leaving a socket in TIME_WAIT.
1145  * This conserves the ephemeral port number space.
1146  *
1147  * Returns zero and fills in "buf" if successful; otherwise, a
1148  * negative errno is returned.
1149  */
1150 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1151                         struct sockaddr *buf, int buflen)
1152 {
1153         struct socket *sock;
1154         int err;
1155
1156         err = __sock_create(net, sap->sa_family,
1157                                 SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1158         if (err < 0) {
1159                 dprintk("RPC:       can't create UDP socket (%d)\n", err);
1160                 goto out;
1161         }
1162
1163         switch (sap->sa_family) {
1164         case AF_INET:
1165                 err = kernel_bind(sock,
1166                                 (struct sockaddr *)&rpc_inaddr_loopback,
1167                                 sizeof(rpc_inaddr_loopback));
1168                 break;
1169         case AF_INET6:
1170                 err = kernel_bind(sock,
1171                                 (struct sockaddr *)&rpc_in6addr_loopback,
1172                                 sizeof(rpc_in6addr_loopback));
1173                 break;
1174         default:
1175                 err = -EAFNOSUPPORT;
1176                 goto out;
1177         }
1178         if (err < 0) {
1179                 dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1180                 goto out_release;
1181         }
1182
1183         err = kernel_connect(sock, sap, salen, 0);
1184         if (err < 0) {
1185                 dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1186                 goto out_release;
1187         }
1188
1189         err = kernel_getsockname(sock, buf, &buflen);
1190         if (err < 0) {
1191                 dprintk("RPC:       getsockname failed (%d)\n", err);
1192                 goto out_release;
1193         }
1194
1195         err = 0;
1196         if (buf->sa_family == AF_INET6) {
1197                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1198                 sin6->sin6_scope_id = 0;
1199         }
1200         dprintk("RPC:       %s succeeded\n", __func__);
1201
1202 out_release:
1203         sock_release(sock);
1204 out:
1205         return err;
1206 }
1207
1208 /*
1209  * Scraping a connected socket failed, so we don't have a useable
1210  * local address.  Fallback: generate an address that will prevent
1211  * the server from calling us back.
1212  *
1213  * Returns zero and fills in "buf" if successful; otherwise, a
1214  * negative errno is returned.
1215  */
1216 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1217 {
1218         switch (family) {
1219         case AF_INET:
1220                 if (buflen < sizeof(rpc_inaddr_loopback))
1221                         return -EINVAL;
1222                 memcpy(buf, &rpc_inaddr_loopback,
1223                                 sizeof(rpc_inaddr_loopback));
1224                 break;
1225         case AF_INET6:
1226                 if (buflen < sizeof(rpc_in6addr_loopback))
1227                         return -EINVAL;
1228                 memcpy(buf, &rpc_in6addr_loopback,
1229                                 sizeof(rpc_in6addr_loopback));
1230         default:
1231                 dprintk("RPC:       %s: address family not supported\n",
1232                         __func__);
1233                 return -EAFNOSUPPORT;
1234         }
1235         dprintk("RPC:       %s: succeeded\n", __func__);
1236         return 0;
1237 }
1238
1239 /**
1240  * rpc_localaddr - discover local endpoint address for an RPC client
1241  * @clnt: RPC client structure
1242  * @buf: target buffer
1243  * @buflen: size of target buffer, in bytes
1244  *
1245  * Returns zero and fills in "buf" and "buflen" if successful;
1246  * otherwise, a negative errno is returned.
1247  *
1248  * This works even if the underlying transport is not currently connected,
1249  * or if the upper layer never previously provided a source address.
1250  *
1251  * The result of this function call is transient: multiple calls in
1252  * succession may give different results, depending on how local
1253  * networking configuration changes over time.
1254  */
1255 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1256 {
1257         struct sockaddr_storage address;
1258         struct sockaddr *sap = (struct sockaddr *)&address;
1259         struct rpc_xprt *xprt;
1260         struct net *net;
1261         size_t salen;
1262         int err;
1263
1264         rcu_read_lock();
1265         xprt = rcu_dereference(clnt->cl_xprt);
1266         salen = xprt->addrlen;
1267         memcpy(sap, &xprt->addr, salen);
1268         net = get_net(xprt->xprt_net);
1269         rcu_read_unlock();
1270
1271         rpc_set_port(sap, 0);
1272         err = rpc_sockname(net, sap, salen, buf, buflen);
1273         put_net(net);
1274         if (err != 0)
1275                 /* Couldn't discover local address, return ANYADDR */
1276                 return rpc_anyaddr(sap->sa_family, buf, buflen);
1277         return 0;
1278 }
1279 EXPORT_SYMBOL_GPL(rpc_localaddr);
1280
1281 void
1282 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1283 {
1284         struct rpc_xprt *xprt;
1285
1286         rcu_read_lock();
1287         xprt = rcu_dereference(clnt->cl_xprt);
1288         if (xprt->ops->set_buffer_size)
1289                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1290         rcu_read_unlock();
1291 }
1292 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1293
1294 /**
1295  * rpc_protocol - Get transport protocol number for an RPC client
1296  * @clnt: RPC client to query
1297  *
1298  */
1299 int rpc_protocol(struct rpc_clnt *clnt)
1300 {
1301         int protocol;
1302
1303         rcu_read_lock();
1304         protocol = rcu_dereference(clnt->cl_xprt)->prot;
1305         rcu_read_unlock();
1306         return protocol;
1307 }
1308 EXPORT_SYMBOL_GPL(rpc_protocol);
1309
1310 /**
1311  * rpc_net_ns - Get the network namespace for this RPC client
1312  * @clnt: RPC client to query
1313  *
1314  */
1315 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1316 {
1317         struct net *ret;
1318
1319         rcu_read_lock();
1320         ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1321         rcu_read_unlock();
1322         return ret;
1323 }
1324 EXPORT_SYMBOL_GPL(rpc_net_ns);
1325
1326 /**
1327  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1328  * @clnt: RPC client to query
1329  *
1330  * For stream transports, this is one RPC record fragment (see RFC
1331  * 1831), as we don't support multi-record requests yet.  For datagram
1332  * transports, this is the size of an IP packet minus the IP, UDP, and
1333  * RPC header sizes.
1334  */
1335 size_t rpc_max_payload(struct rpc_clnt *clnt)
1336 {
1337         size_t ret;
1338
1339         rcu_read_lock();
1340         ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1341         rcu_read_unlock();
1342         return ret;
1343 }
1344 EXPORT_SYMBOL_GPL(rpc_max_payload);
1345
1346 /**
1347  * rpc_get_timeout - Get timeout for transport in units of HZ
1348  * @clnt: RPC client to query
1349  */
1350 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1351 {
1352         unsigned long ret;
1353
1354         rcu_read_lock();
1355         ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1356         rcu_read_unlock();
1357         return ret;
1358 }
1359 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1360
1361 /**
1362  * rpc_force_rebind - force transport to check that remote port is unchanged
1363  * @clnt: client to rebind
1364  *
1365  */
1366 void rpc_force_rebind(struct rpc_clnt *clnt)
1367 {
1368         if (clnt->cl_autobind) {
1369                 rcu_read_lock();
1370                 xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1371                 rcu_read_unlock();
1372         }
1373 }
1374 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1375
1376 /*
1377  * Restart an (async) RPC call from the call_prepare state.
1378  * Usually called from within the exit handler.
1379  */
1380 int
1381 rpc_restart_call_prepare(struct rpc_task *task)
1382 {
1383         if (RPC_ASSASSINATED(task))
1384                 return 0;
1385         task->tk_action = call_start;
1386         task->tk_status = 0;
1387         if (task->tk_ops->rpc_call_prepare != NULL)
1388                 task->tk_action = rpc_prepare_task;
1389         return 1;
1390 }
1391 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1392
1393 /*
1394  * Restart an (async) RPC call. Usually called from within the
1395  * exit handler.
1396  */
1397 int
1398 rpc_restart_call(struct rpc_task *task)
1399 {
1400         if (RPC_ASSASSINATED(task))
1401                 return 0;
1402         task->tk_action = call_start;
1403         task->tk_status = 0;
1404         return 1;
1405 }
1406 EXPORT_SYMBOL_GPL(rpc_restart_call);
1407
1408 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
1409 const char
1410 *rpc_proc_name(const struct rpc_task *task)
1411 {
1412         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1413
1414         if (proc) {
1415                 if (proc->p_name)
1416                         return proc->p_name;
1417                 else
1418                         return "NULL";
1419         } else
1420                 return "no proc";
1421 }
1422 #endif
1423
1424 /*
1425  * 0.  Initial state
1426  *
1427  *     Other FSM states can be visited zero or more times, but
1428  *     this state is visited exactly once for each RPC.
1429  */
1430 static void
1431 call_start(struct rpc_task *task)
1432 {
1433         struct rpc_clnt *clnt = task->tk_client;
1434
1435         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1436                         clnt->cl_program->name, clnt->cl_vers,
1437                         rpc_proc_name(task),
1438                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
1439
1440         /* Increment call count */
1441         task->tk_msg.rpc_proc->p_count++;
1442         clnt->cl_stats->rpccnt++;
1443         task->tk_action = call_reserve;
1444 }
1445
1446 /*
1447  * 1.   Reserve an RPC call slot
1448  */
1449 static void
1450 call_reserve(struct rpc_task *task)
1451 {
1452         dprint_status(task);
1453
1454         task->tk_status  = 0;
1455         task->tk_action  = call_reserveresult;
1456         xprt_reserve(task);
1457 }
1458
1459 static void call_retry_reserve(struct rpc_task *task);
1460
1461 /*
1462  * 1b.  Grok the result of xprt_reserve()
1463  */
1464 static void
1465 call_reserveresult(struct rpc_task *task)
1466 {
1467         int status = task->tk_status;
1468
1469         dprint_status(task);
1470
1471         /*
1472          * After a call to xprt_reserve(), we must have either
1473          * a request slot or else an error status.
1474          */
1475         task->tk_status = 0;
1476         if (status >= 0) {
1477                 if (task->tk_rqstp) {
1478                         task->tk_action = call_refresh;
1479                         return;
1480                 }
1481
1482                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1483                                 __func__, status);
1484                 rpc_exit(task, -EIO);
1485                 return;
1486         }
1487
1488         /*
1489          * Even though there was an error, we may have acquired
1490          * a request slot somehow.  Make sure not to leak it.
1491          */
1492         if (task->tk_rqstp) {
1493                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1494                                 __func__, status);
1495                 xprt_release(task);
1496         }
1497
1498         switch (status) {
1499         case -ENOMEM:
1500                 rpc_delay(task, HZ >> 2);
1501         case -EAGAIN:   /* woken up; retry */
1502                 task->tk_action = call_retry_reserve;
1503                 return;
1504         case -EIO:      /* probably a shutdown */
1505                 break;
1506         default:
1507                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1508                                 __func__, status);
1509                 break;
1510         }
1511         rpc_exit(task, status);
1512 }
1513
1514 /*
1515  * 1c.  Retry reserving an RPC call slot
1516  */
1517 static void
1518 call_retry_reserve(struct rpc_task *task)
1519 {
1520         dprint_status(task);
1521
1522         task->tk_status  = 0;
1523         task->tk_action  = call_reserveresult;
1524         xprt_retry_reserve(task);
1525 }
1526
1527 /*
1528  * 2.   Bind and/or refresh the credentials
1529  */
1530 static void
1531 call_refresh(struct rpc_task *task)
1532 {
1533         dprint_status(task);
1534
1535         task->tk_action = call_refreshresult;
1536         task->tk_status = 0;
1537         task->tk_client->cl_stats->rpcauthrefresh++;
1538         rpcauth_refreshcred(task);
1539 }
1540
1541 /*
1542  * 2a.  Process the results of a credential refresh
1543  */
1544 static void
1545 call_refreshresult(struct rpc_task *task)
1546 {
1547         int status = task->tk_status;
1548
1549         dprint_status(task);
1550
1551         task->tk_status = 0;
1552         task->tk_action = call_refresh;
1553         switch (status) {
1554         case 0:
1555                 if (rpcauth_uptodatecred(task)) {
1556                         task->tk_action = call_allocate;
1557                         return;
1558                 }
1559                 /* Use rate-limiting and a max number of retries if refresh
1560                  * had status 0 but failed to update the cred.
1561                  */
1562         case -ETIMEDOUT:
1563                 rpc_delay(task, 3*HZ);
1564         case -EAGAIN:
1565                 status = -EACCES;
1566         case -EKEYEXPIRED:
1567                 if (!task->tk_cred_retry)
1568                         break;
1569                 task->tk_cred_retry--;
1570                 dprintk("RPC: %5u %s: retry refresh creds\n",
1571                                 task->tk_pid, __func__);
1572                 return;
1573         }
1574         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1575                                 task->tk_pid, __func__, status);
1576         rpc_exit(task, status);
1577 }
1578
1579 /*
1580  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1581  *      (Note: buffer memory is freed in xprt_release).
1582  */
1583 static void
1584 call_allocate(struct rpc_task *task)
1585 {
1586         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1587         struct rpc_rqst *req = task->tk_rqstp;
1588         struct rpc_xprt *xprt = req->rq_xprt;
1589         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1590
1591         dprint_status(task);
1592
1593         task->tk_status = 0;
1594         task->tk_action = call_bind;
1595
1596         if (req->rq_buffer)
1597                 return;
1598
1599         if (proc->p_proc != 0) {
1600                 BUG_ON(proc->p_arglen == 0);
1601                 if (proc->p_decode != NULL)
1602                         BUG_ON(proc->p_replen == 0);
1603         }
1604
1605         /*
1606          * Calculate the size (in quads) of the RPC call
1607          * and reply headers, and convert both values
1608          * to byte sizes.
1609          */
1610         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1611         req->rq_callsize <<= 2;
1612         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1613         req->rq_rcvsize <<= 2;
1614
1615         req->rq_buffer = xprt->ops->buf_alloc(task,
1616                                         req->rq_callsize + req->rq_rcvsize);
1617         if (req->rq_buffer != NULL)
1618                 return;
1619
1620         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1621
1622         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1623                 task->tk_action = call_allocate;
1624                 rpc_delay(task, HZ>>4);
1625                 return;
1626         }
1627
1628         rpc_exit(task, -ERESTARTSYS);
1629 }
1630
1631 static inline int
1632 rpc_task_need_encode(struct rpc_task *task)
1633 {
1634         return task->tk_rqstp->rq_snd_buf.len == 0;
1635 }
1636
1637 static inline void
1638 rpc_task_force_reencode(struct rpc_task *task)
1639 {
1640         task->tk_rqstp->rq_snd_buf.len = 0;
1641         task->tk_rqstp->rq_bytes_sent = 0;
1642 }
1643
1644 static inline void
1645 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1646 {
1647         buf->head[0].iov_base = start;
1648         buf->head[0].iov_len = len;
1649         buf->tail[0].iov_len = 0;
1650         buf->page_len = 0;
1651         buf->flags = 0;
1652         buf->len = 0;
1653         buf->buflen = len;
1654 }
1655
1656 /*
1657  * 3.   Encode arguments of an RPC call
1658  */
1659 static void
1660 rpc_xdr_encode(struct rpc_task *task)
1661 {
1662         struct rpc_rqst *req = task->tk_rqstp;
1663         kxdreproc_t     encode;
1664         __be32          *p;
1665
1666         dprint_status(task);
1667
1668         rpc_xdr_buf_init(&req->rq_snd_buf,
1669                          req->rq_buffer,
1670                          req->rq_callsize);
1671         rpc_xdr_buf_init(&req->rq_rcv_buf,
1672                          (char *)req->rq_buffer + req->rq_callsize,
1673                          req->rq_rcvsize);
1674
1675         p = rpc_encode_header(task);
1676         if (p == NULL) {
1677                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1678                 rpc_exit(task, -EIO);
1679                 return;
1680         }
1681
1682         encode = task->tk_msg.rpc_proc->p_encode;
1683         if (encode == NULL)
1684                 return;
1685
1686         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1687                         task->tk_msg.rpc_argp);
1688 }
1689
1690 /*
1691  * 4.   Get the server port number if not yet set
1692  */
1693 static void
1694 call_bind(struct rpc_task *task)
1695 {
1696         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1697
1698         dprint_status(task);
1699
1700         task->tk_action = call_connect;
1701         if (!xprt_bound(xprt)) {
1702                 task->tk_action = call_bind_status;
1703                 task->tk_timeout = xprt->bind_timeout;
1704                 xprt->ops->rpcbind(task);
1705         }
1706 }
1707
1708 /*
1709  * 4a.  Sort out bind result
1710  */
1711 static void
1712 call_bind_status(struct rpc_task *task)
1713 {
1714         int status = -EIO;
1715
1716         if (task->tk_status >= 0) {
1717                 dprint_status(task);
1718                 task->tk_status = 0;
1719                 task->tk_action = call_connect;
1720                 return;
1721         }
1722
1723         trace_rpc_bind_status(task);
1724         switch (task->tk_status) {
1725         case -ENOMEM:
1726                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1727                 rpc_delay(task, HZ >> 2);
1728                 goto retry_timeout;
1729         case -EACCES:
1730                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1731                                 "unavailable\n", task->tk_pid);
1732                 /* fail immediately if this is an RPC ping */
1733                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1734                         status = -EOPNOTSUPP;
1735                         break;
1736                 }
1737                 if (task->tk_rebind_retry == 0)
1738                         break;
1739                 task->tk_rebind_retry--;
1740                 rpc_delay(task, 3*HZ);
1741                 goto retry_timeout;
1742         case -ETIMEDOUT:
1743                 dprintk("RPC: %5u rpcbind request timed out\n",
1744                                 task->tk_pid);
1745                 goto retry_timeout;
1746         case -EPFNOSUPPORT:
1747                 /* server doesn't support any rpcbind version we know of */
1748                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1749                                 task->tk_pid);
1750                 break;
1751         case -EPROTONOSUPPORT:
1752                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1753                                 task->tk_pid);
1754                 goto retry_timeout;
1755         case -ECONNREFUSED:             /* connection problems */
1756         case -ECONNRESET:
1757         case -ECONNABORTED:
1758         case -ENOTCONN:
1759         case -EHOSTDOWN:
1760         case -EHOSTUNREACH:
1761         case -ENETUNREACH:
1762         case -ENOBUFS:
1763         case -EPIPE:
1764                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1765                                 task->tk_pid, task->tk_status);
1766                 if (!RPC_IS_SOFTCONN(task)) {
1767                         rpc_delay(task, 5*HZ);
1768                         goto retry_timeout;
1769                 }
1770                 status = task->tk_status;
1771                 break;
1772         default:
1773                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1774                                 task->tk_pid, -task->tk_status);
1775         }
1776
1777         rpc_exit(task, status);
1778         return;
1779
1780 retry_timeout:
1781         task->tk_status = 0;
1782         task->tk_action = call_timeout;
1783 }
1784
1785 /*
1786  * 4b.  Connect to the RPC server
1787  */
1788 static void
1789 call_connect(struct rpc_task *task)
1790 {
1791         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1792
1793         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1794                         task->tk_pid, xprt,
1795                         (xprt_connected(xprt) ? "is" : "is not"));
1796
1797         task->tk_action = call_transmit;
1798         if (!xprt_connected(xprt)) {
1799                 task->tk_action = call_connect_status;
1800                 if (task->tk_status < 0)
1801                         return;
1802                 if (task->tk_flags & RPC_TASK_NOCONNECT) {
1803                         rpc_exit(task, -ENOTCONN);
1804                         return;
1805                 }
1806                 xprt_connect(task);
1807         }
1808 }
1809
1810 /*
1811  * 4c.  Sort out connect result
1812  */
1813 static void
1814 call_connect_status(struct rpc_task *task)
1815 {
1816         struct rpc_clnt *clnt = task->tk_client;
1817         int status = task->tk_status;
1818
1819         dprint_status(task);
1820
1821         trace_rpc_connect_status(task, status);
1822         task->tk_status = 0;
1823         switch (status) {
1824         case -ECONNREFUSED:
1825         case -ECONNRESET:
1826         case -ECONNABORTED:
1827         case -ENETUNREACH:
1828         case -EHOSTUNREACH:
1829         case -EADDRINUSE:
1830         case -ENOBUFS:
1831         case -EPIPE:
1832                 if (RPC_IS_SOFTCONN(task))
1833                         break;
1834                 /* retry with existing socket, after a delay */
1835                 rpc_delay(task, 3*HZ);
1836         case -EAGAIN:
1837                 /* Check for timeouts before looping back to call_bind */
1838         case -ETIMEDOUT:
1839                 task->tk_action = call_timeout;
1840                 return;
1841         case 0:
1842                 clnt->cl_stats->netreconn++;
1843                 task->tk_action = call_transmit;
1844                 return;
1845         }
1846         rpc_exit(task, status);
1847 }
1848
1849 /*
1850  * 5.   Transmit the RPC request, and wait for reply
1851  */
1852 static void
1853 call_transmit(struct rpc_task *task)
1854 {
1855         int is_retrans = RPC_WAS_SENT(task);
1856
1857         dprint_status(task);
1858
1859         task->tk_action = call_status;
1860         if (task->tk_status < 0)
1861                 return;
1862         if (!xprt_prepare_transmit(task))
1863                 return;
1864         task->tk_action = call_transmit_status;
1865         /* Encode here so that rpcsec_gss can use correct sequence number. */
1866         if (rpc_task_need_encode(task)) {
1867                 rpc_xdr_encode(task);
1868                 /* Did the encode result in an error condition? */
1869                 if (task->tk_status != 0) {
1870                         /* Was the error nonfatal? */
1871                         if (task->tk_status == -EAGAIN)
1872                                 rpc_delay(task, HZ >> 4);
1873                         else
1874                                 rpc_exit(task, task->tk_status);
1875                         return;
1876                 }
1877         }
1878         xprt_transmit(task);
1879         if (task->tk_status < 0)
1880                 return;
1881         if (is_retrans)
1882                 task->tk_client->cl_stats->rpcretrans++;
1883         /*
1884          * On success, ensure that we call xprt_end_transmit() before sleeping
1885          * in order to allow access to the socket to other RPC requests.
1886          */
1887         call_transmit_status(task);
1888         if (rpc_reply_expected(task))
1889                 return;
1890         task->tk_action = rpc_exit_task;
1891         rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1892 }
1893
1894 /*
1895  * 5a.  Handle cleanup after a transmission
1896  */
1897 static void
1898 call_transmit_status(struct rpc_task *task)
1899 {
1900         task->tk_action = call_status;
1901
1902         /*
1903          * Common case: success.  Force the compiler to put this
1904          * test first.
1905          */
1906         if (task->tk_status == 0) {
1907                 xprt_end_transmit(task);
1908                 rpc_task_force_reencode(task);
1909                 return;
1910         }
1911
1912         switch (task->tk_status) {
1913         case -EAGAIN:
1914                 break;
1915         default:
1916                 dprint_status(task);
1917                 xprt_end_transmit(task);
1918                 rpc_task_force_reencode(task);
1919                 break;
1920                 /*
1921                  * Special cases: if we've been waiting on the
1922                  * socket's write_space() callback, or if the
1923                  * socket just returned a connection error,
1924                  * then hold onto the transport lock.
1925                  */
1926         case -ECONNREFUSED:
1927         case -EHOSTDOWN:
1928         case -EHOSTUNREACH:
1929         case -ENETUNREACH:
1930         case -EPERM:
1931                 if (RPC_IS_SOFTCONN(task)) {
1932                         xprt_end_transmit(task);
1933                         rpc_exit(task, task->tk_status);
1934                         break;
1935                 }
1936         case -ECONNRESET:
1937         case -ECONNABORTED:
1938         case -EADDRINUSE:
1939         case -ENOTCONN:
1940         case -ENOBUFS:
1941         case -EPIPE:
1942                 rpc_task_force_reencode(task);
1943         }
1944 }
1945
1946 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1947 /*
1948  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1949  * addition, disconnect on connectivity errors.
1950  */
1951 static void
1952 call_bc_transmit(struct rpc_task *task)
1953 {
1954         struct rpc_rqst *req = task->tk_rqstp;
1955
1956         if (!xprt_prepare_transmit(task)) {
1957                 /*
1958                  * Could not reserve the transport. Try again after the
1959                  * transport is released.
1960                  */
1961                 task->tk_status = 0;
1962                 task->tk_action = call_bc_transmit;
1963                 return;
1964         }
1965
1966         task->tk_action = rpc_exit_task;
1967         if (task->tk_status < 0) {
1968                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1969                         "error: %d\n", task->tk_status);
1970                 return;
1971         }
1972
1973         xprt_transmit(task);
1974         xprt_end_transmit(task);
1975         dprint_status(task);
1976         switch (task->tk_status) {
1977         case 0:
1978                 /* Success */
1979                 break;
1980         case -EHOSTDOWN:
1981         case -EHOSTUNREACH:
1982         case -ENETUNREACH:
1983         case -ETIMEDOUT:
1984                 /*
1985                  * Problem reaching the server.  Disconnect and let the
1986                  * forechannel reestablish the connection.  The server will
1987                  * have to retransmit the backchannel request and we'll
1988                  * reprocess it.  Since these ops are idempotent, there's no
1989                  * need to cache our reply at this time.
1990                  */
1991                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1992                         "error: %d\n", task->tk_status);
1993                 xprt_conditional_disconnect(req->rq_xprt,
1994                         req->rq_connect_cookie);
1995                 break;
1996         default:
1997                 /*
1998                  * We were unable to reply and will have to drop the
1999                  * request.  The server should reconnect and retransmit.
2000                  */
2001                 WARN_ON_ONCE(task->tk_status == -EAGAIN);
2002                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
2003                         "error: %d\n", task->tk_status);
2004                 break;
2005         }
2006         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
2007 }
2008 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
2009
2010 /*
2011  * 6.   Sort out the RPC call status
2012  */
2013 static void
2014 call_status(struct rpc_task *task)
2015 {
2016         struct rpc_clnt *clnt = task->tk_client;
2017         struct rpc_rqst *req = task->tk_rqstp;
2018         int             status;
2019
2020         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
2021                 task->tk_status = req->rq_reply_bytes_recvd;
2022
2023         dprint_status(task);
2024
2025         status = task->tk_status;
2026         if (status >= 0) {
2027                 task->tk_action = call_decode;
2028                 return;
2029         }
2030
2031         trace_rpc_call_status(task);
2032         task->tk_status = 0;
2033         switch(status) {
2034         case -EHOSTDOWN:
2035         case -EHOSTUNREACH:
2036         case -ENETUNREACH:
2037         case -EPERM:
2038                 if (RPC_IS_SOFTCONN(task)) {
2039                         rpc_exit(task, status);
2040                         break;
2041                 }
2042                 /*
2043                  * Delay any retries for 3 seconds, then handle as if it
2044                  * were a timeout.
2045                  */
2046                 rpc_delay(task, 3*HZ);
2047         case -ETIMEDOUT:
2048                 task->tk_action = call_timeout;
2049                 if (!(task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT)
2050                     && task->tk_client->cl_discrtry)
2051                         xprt_conditional_disconnect(req->rq_xprt,
2052                                         req->rq_connect_cookie);
2053                 break;
2054         case -ECONNREFUSED:
2055         case -ECONNRESET:
2056         case -ECONNABORTED:
2057                 rpc_force_rebind(clnt);
2058         case -EADDRINUSE:
2059         case -ENOBUFS:
2060                 rpc_delay(task, 3*HZ);
2061         case -EPIPE:
2062         case -ENOTCONN:
2063                 task->tk_action = call_bind;
2064                 break;
2065         case -EAGAIN:
2066                 task->tk_action = call_transmit;
2067                 break;
2068         case -EIO:
2069                 /* shutdown or soft timeout */
2070                 rpc_exit(task, status);
2071                 break;
2072         default:
2073                 if (clnt->cl_chatty)
2074                         printk("%s: RPC call returned error %d\n",
2075                                clnt->cl_program->name, -status);
2076                 rpc_exit(task, status);
2077         }
2078 }
2079
2080 /*
2081  * 6a.  Handle RPC timeout
2082  *      We do not release the request slot, so we keep using the
2083  *      same XID for all retransmits.
2084  */
2085 static void
2086 call_timeout(struct rpc_task *task)
2087 {
2088         struct rpc_clnt *clnt = task->tk_client;
2089
2090         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
2091                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
2092                 goto retry;
2093         }
2094
2095         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
2096         task->tk_timeouts++;
2097
2098         if (RPC_IS_SOFTCONN(task)) {
2099                 rpc_exit(task, -ETIMEDOUT);
2100                 return;
2101         }
2102         if (RPC_IS_SOFT(task)) {
2103                 if (clnt->cl_chatty) {
2104                         rcu_read_lock();
2105                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
2106                                 clnt->cl_program->name,
2107                                 rcu_dereference(clnt->cl_xprt)->servername);
2108                         rcu_read_unlock();
2109                 }
2110                 if (task->tk_flags & RPC_TASK_TIMEOUT)
2111                         rpc_exit(task, -ETIMEDOUT);
2112                 else
2113                         rpc_exit(task, -EIO);
2114                 return;
2115         }
2116
2117         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
2118                 task->tk_flags |= RPC_CALL_MAJORSEEN;
2119                 if (clnt->cl_chatty) {
2120                         rcu_read_lock();
2121                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
2122                         clnt->cl_program->name,
2123                         rcu_dereference(clnt->cl_xprt)->servername);
2124                         rcu_read_unlock();
2125                 }
2126         }
2127         rpc_force_rebind(clnt);
2128         /*
2129          * Did our request time out due to an RPCSEC_GSS out-of-sequence
2130          * event? RFC2203 requires the server to drop all such requests.
2131          */
2132         rpcauth_invalcred(task);
2133
2134 retry:
2135         task->tk_action = call_bind;
2136         task->tk_status = 0;
2137 }
2138
2139 /*
2140  * 7.   Decode the RPC reply
2141  */
2142 static void
2143 call_decode(struct rpc_task *task)
2144 {
2145         struct rpc_clnt *clnt = task->tk_client;
2146         struct rpc_rqst *req = task->tk_rqstp;
2147         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
2148         __be32          *p;
2149
2150         dprint_status(task);
2151
2152         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
2153                 if (clnt->cl_chatty) {
2154                         rcu_read_lock();
2155                         printk(KERN_NOTICE "%s: server %s OK\n",
2156                                 clnt->cl_program->name,
2157                                 rcu_dereference(clnt->cl_xprt)->servername);
2158                         rcu_read_unlock();
2159                 }
2160                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
2161         }
2162
2163         /*
2164          * Ensure that we see all writes made by xprt_complete_rqst()
2165          * before it changed req->rq_reply_bytes_recvd.
2166          */
2167         smp_rmb();
2168         req->rq_rcv_buf.len = req->rq_private_buf.len;
2169
2170         /* Check that the softirq receive buffer is valid */
2171         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
2172                                 sizeof(req->rq_rcv_buf)) != 0);
2173
2174         if (req->rq_rcv_buf.len < 12) {
2175                 if (!RPC_IS_SOFT(task)) {
2176                         task->tk_action = call_bind;
2177                         goto out_retry;
2178                 }
2179                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2180                                 clnt->cl_program->name, task->tk_status);
2181                 task->tk_action = call_timeout;
2182                 goto out_retry;
2183         }
2184
2185         p = rpc_verify_header(task);
2186         if (IS_ERR(p)) {
2187                 if (p == ERR_PTR(-EAGAIN))
2188                         goto out_retry;
2189                 return;
2190         }
2191
2192         task->tk_action = rpc_exit_task;
2193
2194         if (decode) {
2195                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2196                                                       task->tk_msg.rpc_resp);
2197         }
2198         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2199                         task->tk_status);
2200         return;
2201 out_retry:
2202         task->tk_status = 0;
2203         /* Note: rpc_verify_header() may have freed the RPC slot */
2204         if (task->tk_rqstp == req) {
2205                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2206                 if (task->tk_client->cl_discrtry)
2207                         xprt_conditional_disconnect(req->rq_xprt,
2208                                         req->rq_connect_cookie);
2209         }
2210 }
2211
2212 static __be32 *
2213 rpc_encode_header(struct rpc_task *task)
2214 {
2215         struct rpc_clnt *clnt = task->tk_client;
2216         struct rpc_rqst *req = task->tk_rqstp;
2217         __be32          *p = req->rq_svec[0].iov_base;
2218
2219         /* FIXME: check buffer size? */
2220
2221         p = xprt_skip_transport_header(req->rq_xprt, p);
2222         *p++ = req->rq_xid;             /* XID */
2223         *p++ = htonl(RPC_CALL);         /* CALL */
2224         *p++ = htonl(RPC_VERSION);      /* RPC version */
2225         *p++ = htonl(clnt->cl_prog);    /* program number */
2226         *p++ = htonl(clnt->cl_vers);    /* program version */
2227         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
2228         p = rpcauth_marshcred(task, p);
2229         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2230         return p;
2231 }
2232
2233 static __be32 *
2234 rpc_verify_header(struct rpc_task *task)
2235 {
2236         struct rpc_clnt *clnt = task->tk_client;
2237         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2238         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2239         __be32  *p = iov->iov_base;
2240         u32 n;
2241         int error = -EACCES;
2242
2243         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2244                 /* RFC-1014 says that the representation of XDR data must be a
2245                  * multiple of four bytes
2246                  * - if it isn't pointer subtraction in the NFS client may give
2247                  *   undefined results
2248                  */
2249                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
2250                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2251                        task->tk_rqstp->rq_rcv_buf.len);
2252                 error = -EIO;
2253                 goto out_err;
2254         }
2255         if ((len -= 3) < 0)
2256                 goto out_overflow;
2257
2258         p += 1; /* skip XID */
2259         if ((n = ntohl(*p++)) != RPC_REPLY) {
2260                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2261                         task->tk_pid, __func__, n);
2262                 error = -EIO;
2263                 goto out_garbage;
2264         }
2265
2266         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2267                 if (--len < 0)
2268                         goto out_overflow;
2269                 switch ((n = ntohl(*p++))) {
2270                 case RPC_AUTH_ERROR:
2271                         break;
2272                 case RPC_MISMATCH:
2273                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2274                                 task->tk_pid, __func__);
2275                         error = -EPROTONOSUPPORT;
2276                         goto out_err;
2277                 default:
2278                         dprintk("RPC: %5u %s: RPC call rejected, "
2279                                 "unknown error: %x\n",
2280                                 task->tk_pid, __func__, n);
2281                         error = -EIO;
2282                         goto out_err;
2283                 }
2284                 if (--len < 0)
2285                         goto out_overflow;
2286                 switch ((n = ntohl(*p++))) {
2287                 case RPC_AUTH_REJECTEDCRED:
2288                 case RPC_AUTH_REJECTEDVERF:
2289                 case RPCSEC_GSS_CREDPROBLEM:
2290                 case RPCSEC_GSS_CTXPROBLEM:
2291                         if (!task->tk_cred_retry)
2292                                 break;
2293                         task->tk_cred_retry--;
2294                         dprintk("RPC: %5u %s: retry stale creds\n",
2295                                         task->tk_pid, __func__);
2296                         rpcauth_invalcred(task);
2297                         /* Ensure we obtain a new XID! */
2298                         xprt_release(task);
2299                         task->tk_action = call_reserve;
2300                         goto out_retry;
2301                 case RPC_AUTH_BADCRED:
2302                 case RPC_AUTH_BADVERF:
2303                         /* possibly garbled cred/verf? */
2304                         if (!task->tk_garb_retry)
2305                                 break;
2306                         task->tk_garb_retry--;
2307                         dprintk("RPC: %5u %s: retry garbled creds\n",
2308                                         task->tk_pid, __func__);
2309                         task->tk_action = call_bind;
2310                         goto out_retry;
2311                 case RPC_AUTH_TOOWEAK:
2312                         rcu_read_lock();
2313                         printk(KERN_NOTICE "RPC: server %s requires stronger "
2314                                "authentication.\n",
2315                                rcu_dereference(clnt->cl_xprt)->servername);
2316                         rcu_read_unlock();
2317                         break;
2318                 default:
2319                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
2320                                         task->tk_pid, __func__, n);
2321                         error = -EIO;
2322                 }
2323                 dprintk("RPC: %5u %s: call rejected %d\n",
2324                                 task->tk_pid, __func__, n);
2325                 goto out_err;
2326         }
2327         p = rpcauth_checkverf(task, p);
2328         if (IS_ERR(p)) {
2329                 error = PTR_ERR(p);
2330                 dprintk("RPC: %5u %s: auth check failed with %d\n",
2331                                 task->tk_pid, __func__, error);
2332                 goto out_garbage;               /* bad verifier, retry */
2333         }
2334         len = p - (__be32 *)iov->iov_base - 1;
2335         if (len < 0)
2336                 goto out_overflow;
2337         switch ((n = ntohl(*p++))) {
2338         case RPC_SUCCESS:
2339                 return p;
2340         case RPC_PROG_UNAVAIL:
2341                 dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2342                                 "by server %s\n", task->tk_pid, __func__,
2343                                 (unsigned int)clnt->cl_prog,
2344                                 rcu_dereference(clnt->cl_xprt)->servername);
2345                 error = -EPFNOSUPPORT;
2346                 goto out_err;
2347         case RPC_PROG_MISMATCH:
2348                 dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2349                                 "by server %s\n", task->tk_pid, __func__,
2350                                 (unsigned int)clnt->cl_prog,
2351                                 (unsigned int)clnt->cl_vers,
2352                                 rcu_dereference(clnt->cl_xprt)->servername);
2353                 error = -EPROTONOSUPPORT;
2354                 goto out_err;
2355         case RPC_PROC_UNAVAIL:
2356                 dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2357                                 "version %u on server %s\n",
2358                                 task->tk_pid, __func__,
2359                                 rpc_proc_name(task),
2360                                 clnt->cl_prog, clnt->cl_vers,
2361                                 rcu_dereference(clnt->cl_xprt)->servername);
2362                 error = -EOPNOTSUPP;
2363                 goto out_err;
2364         case RPC_GARBAGE_ARGS:
2365                 dprintk("RPC: %5u %s: server saw garbage\n",
2366                                 task->tk_pid, __func__);
2367                 break;                  /* retry */
2368         default:
2369                 dprintk("RPC: %5u %s: server accept status: %x\n",
2370                                 task->tk_pid, __func__, n);
2371                 /* Also retry */
2372         }
2373
2374 out_garbage:
2375         clnt->cl_stats->rpcgarbage++;
2376         if (task->tk_garb_retry) {
2377                 task->tk_garb_retry--;
2378                 dprintk("RPC: %5u %s: retrying\n",
2379                                 task->tk_pid, __func__);
2380                 task->tk_action = call_bind;
2381 out_retry:
2382                 return ERR_PTR(-EAGAIN);
2383         }
2384 out_err:
2385         rpc_exit(task, error);
2386         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2387                         __func__, error);
2388         return ERR_PTR(error);
2389 out_overflow:
2390         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2391                         __func__);
2392         goto out_garbage;
2393 }
2394
2395 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2396 {
2397 }
2398
2399 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2400 {
2401         return 0;
2402 }
2403
2404 static struct rpc_procinfo rpcproc_null = {
2405         .p_encode = rpcproc_encode_null,
2406         .p_decode = rpcproc_decode_null,
2407 };
2408
2409 static int rpc_ping(struct rpc_clnt *clnt)
2410 {
2411         struct rpc_message msg = {
2412                 .rpc_proc = &rpcproc_null,
2413         };
2414         int err;
2415         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2416         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2417         put_rpccred(msg.rpc_cred);
2418         return err;
2419 }
2420
2421 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2422 {
2423         struct rpc_message msg = {
2424                 .rpc_proc = &rpcproc_null,
2425                 .rpc_cred = cred,
2426         };
2427         struct rpc_task_setup task_setup_data = {
2428                 .rpc_client = clnt,
2429                 .rpc_message = &msg,
2430                 .callback_ops = &rpc_default_ops,
2431                 .flags = flags,
2432         };
2433         return rpc_run_task(&task_setup_data);
2434 }
2435 EXPORT_SYMBOL_GPL(rpc_call_null);
2436
2437 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
2438 static void rpc_show_header(void)
2439 {
2440         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2441                 "-timeout ---ops--\n");
2442 }
2443
2444 static void rpc_show_task(const struct rpc_clnt *clnt,
2445                           const struct rpc_task *task)
2446 {
2447         const char *rpc_waitq = "none";
2448
2449         if (RPC_IS_QUEUED(task))
2450                 rpc_waitq = rpc_qname(task->tk_waitqueue);
2451
2452         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2453                 task->tk_pid, task->tk_flags, task->tk_status,
2454                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2455                 clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
2456                 task->tk_action, rpc_waitq);
2457 }
2458
2459 void rpc_show_tasks(struct net *net)
2460 {
2461         struct rpc_clnt *clnt;
2462         struct rpc_task *task;
2463         int header = 0;
2464         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2465
2466         spin_lock(&sn->rpc_client_lock);
2467         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2468                 spin_lock(&clnt->cl_lock);
2469                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2470                         if (!header) {
2471                                 rpc_show_header();
2472                                 header++;
2473                         }
2474                         rpc_show_task(clnt, task);
2475                 }
2476                 spin_unlock(&clnt->cl_lock);
2477         }
2478         spin_unlock(&sn->rpc_client_lock);
2479 }
2480 #endif