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