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  *  NB: BSD uses a more intelligent approach to guessing when a request
  17  *  or reply has been lost by keeping the RTO estimate for each procedure.
  18  *  We currently make do with a constant timeout value.
  19  *
  20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  22  */
  23
  24 #include <asm/system.h>
  25
  26 #include <linux/module.h>
  27 #include <linux/types.h>
  28 #include <linux/mm.h>
  29 #include <linux/slab.h>
  30 #include <linux/utsname.h>
  31 #include <linux/workqueue.h>
  32
  33 #include <linux/sunrpc/clnt.h>
  34 #include <linux/sunrpc/rpc_pipe_fs.h>
  35 #include <linux/sunrpc/metrics.h>
  36
  37
  38 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
  39
  40 #ifdef RPC_DEBUG
  41 # define RPCDBG_FACILITY        RPCDBG_CALL
  42 #endif
  43
  44 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  45
  46
  47 static void     call_start(struct rpc_task *task);
  48 static void     call_reserve(struct rpc_task *task);
  49 static void     call_reserveresult(struct rpc_task *task);
  50 static void     call_allocate(struct rpc_task *task);
  51 static void     call_encode(struct rpc_task *task);
  52 static void     call_decode(struct rpc_task *task);
  53 static void     call_bind(struct rpc_task *task);
  54 static void     call_bind_status(struct rpc_task *task);
  55 static void     call_transmit(struct rpc_task *task);
  56 static void     call_status(struct rpc_task *task);
  57 static void     call_transmit_status(struct rpc_task *task);
  58 static void     call_refresh(struct rpc_task *task);
  59 static void     call_refreshresult(struct rpc_task *task);
  60 static void     call_timeout(struct rpc_task *task);
  61 static void     call_connect(struct rpc_task *task);
  62 static void     call_connect_status(struct rpc_task *task);
  63 static __be32 * call_header(struct rpc_task *task);
  64 static __be32 * call_verify(struct rpc_task *task);
  65
  66
  67 static int
  68 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  69 {
  70         static uint32_t clntid;
  71         int error;
  72
  73         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  74         clnt->cl_dentry = ERR_PTR(-ENOENT);
  75         if (dir_name == NULL)
  76                 return 0;
  77
  78         clnt->cl_vfsmnt = rpc_get_mount();
  79         if (IS_ERR(clnt->cl_vfsmnt))
  80                 return PTR_ERR(clnt->cl_vfsmnt);
  81
  82         for (;;) {
  83                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  84                                 "%s/clnt%x", dir_name,
  85                                 (unsigned int)clntid++);
  86                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  87                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  88                 if (!IS_ERR(clnt->cl_dentry))
  89                         return 0;
  90                 error = PTR_ERR(clnt->cl_dentry);
  91                 if (error != -EEXIST) {
  92                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  93                                         clnt->cl_pathname, error);
  94                         rpc_put_mount();
  95                         return error;
  96                 }
  97         }
  98 }
  99
 100 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
 101 {
 102         struct rpc_version      *version;
 103         struct rpc_clnt         *clnt = NULL;
 104         struct rpc_auth         *auth;
 105         int err;
 106         int len;
 107
 108         dprintk("RPC: creating %s client for %s (xprt %p)\n",
 109                 program->name, servname, xprt);
 110
 111         err = -EINVAL;
 112         if (!xprt)
 113                 goto out_no_xprt;
 114         if (vers >= program->nrvers || !(version = program->version[vers]))
 115                 goto out_err;
 116
 117         err = -ENOMEM;
 118         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 119         if (!clnt)
 120                 goto out_err;
 121         atomic_set(&clnt->cl_users, 0);
 122         atomic_set(&clnt->cl_count, 1);
 123         clnt->cl_parent = clnt;
 124
 125         clnt->cl_server = clnt->cl_inline_name;
 126         len = strlen(servname) + 1;
 127         if (len > sizeof(clnt->cl_inline_name)) {
 128                 char *buf = kmalloc(len, GFP_KERNEL);
 129                 if (buf != 0)
 130                         clnt->cl_server = buf;
 131                 else
 132                         len = sizeof(clnt->cl_inline_name);
 133         }
 134         strlcpy(clnt->cl_server, servname, len);
 135
 136         clnt->cl_xprt     = xprt;
 137         clnt->cl_procinfo = version->procs;
 138         clnt->cl_maxproc  = version->nrprocs;
 139         clnt->cl_protname = program->name;
 140         clnt->cl_prog     = program->number;
 141         clnt->cl_vers     = version->number;
 142         clnt->cl_stats    = program->stats;
 143         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 144         err = -ENOMEM;
 145         if (clnt->cl_metrics == NULL)
 146                 goto out_no_stats;
 147
 148         if (!xprt_bound(clnt->cl_xprt))
 149                 clnt->cl_autobind = 1;
 150
 151         clnt->cl_rtt = &clnt->cl_rtt_default;
 152         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 153
 154         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 155         if (err < 0)
 156                 goto out_no_path;
 157
 158         auth = rpcauth_create(flavor, clnt);
 159         if (IS_ERR(auth)) {
 160                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 161                                 flavor);
 162                 err = PTR_ERR(auth);
 163                 goto out_no_auth;
 164         }
 165
 166         /* save the nodename */
 167         clnt->cl_nodelen = strlen(utsname()->nodename);
 168         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 169                 clnt->cl_nodelen = UNX_MAXNODENAME;
 170         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 171         return clnt;
 172
 173 out_no_auth:
 174         if (!IS_ERR(clnt->cl_dentry)) {
 175                 rpc_rmdir(clnt->cl_dentry);
 176                 rpc_put_mount();
 177         }
 178 out_no_path:
 179         rpc_free_iostats(clnt->cl_metrics);
 180 out_no_stats:
 181         if (clnt->cl_server != clnt->cl_inline_name)
 182                 kfree(clnt->cl_server);
 183         kfree(clnt);
 184 out_err:
 185         xprt_put(xprt);
 186 out_no_xprt:
 187         return ERR_PTR(err);
 188 }
 189
 190 /*
 191  * rpc_create - create an RPC client and transport with one call
 192  * @args: rpc_clnt create argument structure
 193  *
 194  * Creates and initializes an RPC transport and an RPC client.
 195  *
 196  * It can ping the server in order to determine if it is up, and to see if
 197  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 198  * this behavior so asynchronous tasks can also use rpc_create.
 199  */
 200 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 201 {
 202         struct rpc_xprt *xprt;
 203         struct rpc_clnt *clnt;
 204
 205         xprt = xprt_create_transport(args->protocol, args->address,
 206                                         args->addrsize, args->timeout);
 207         if (IS_ERR(xprt))
 208                 return (struct rpc_clnt *)xprt;
 209
 210         /*
 211          * By default, kernel RPC client connects from a reserved port.
 212          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 213          * but it is always enabled for rpciod, which handles the connect
 214          * operation.
 215          */
 216         xprt->resvport = 1;
 217         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 218                 xprt->resvport = 0;
 219
 220         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 221                 args->program->name, args->servername, xprt);
 222
 223         clnt = rpc_new_client(xprt, args->servername, args->program,
 224                                 args->version, args->authflavor);
 225         if (IS_ERR(clnt))
 226                 return clnt;
 227
 228         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 229                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 230                 if (err != 0) {
 231                         rpc_shutdown_client(clnt);
 232                         return ERR_PTR(err);
 233                 }
 234         }
 235
 236         clnt->cl_softrtry = 1;
 237         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 238                 clnt->cl_softrtry = 0;
 239
 240         if (args->flags & RPC_CLNT_CREATE_INTR)
 241                 clnt->cl_intr = 1;
 242         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 243                 clnt->cl_autobind = 1;
 244         if (args->flags & RPC_CLNT_CREATE_ONESHOT)
 245                 clnt->cl_oneshot = 1;
 246
 247         return clnt;
 248 }
 249 EXPORT_SYMBOL_GPL(rpc_create);
 250
 251 /*
 252  * This function clones the RPC client structure. It allows us to share the
 253  * same transport while varying parameters such as the authentication
 254  * flavour.
 255  */
 256 struct rpc_clnt *
 257 rpc_clone_client(struct rpc_clnt *clnt)
 258 {
 259         struct rpc_clnt *new;
 260
 261         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 262         if (!new)
 263                 goto out_no_clnt;
 264         atomic_set(&new->cl_count, 1);
 265         atomic_set(&new->cl_users, 0);
 266         new->cl_metrics = rpc_alloc_iostats(clnt);
 267         if (new->cl_metrics == NULL)
 268                 goto out_no_stats;
 269         new->cl_parent = clnt;
 270         atomic_inc(&clnt->cl_count);
 271         new->cl_xprt = xprt_get(clnt->cl_xprt);
 272         /* Turn off autobind on clones */
 273         new->cl_autobind = 0;
 274         new->cl_oneshot = 0;
 275         new->cl_dead = 0;
 276         if (!IS_ERR(new->cl_dentry))
 277                 dget(new->cl_dentry);
 278         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 279         if (new->cl_auth)
 280                 atomic_inc(&new->cl_auth->au_count);
 281         return new;
 282 out_no_stats:
 283         kfree(new);
 284 out_no_clnt:
 285         printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
 286         return ERR_PTR(-ENOMEM);
 287 }
 288
 289 /*
 290  * Properly shut down an RPC client, terminating all outstanding
 291  * requests. Note that we must be certain that cl_oneshot and
 292  * cl_dead are cleared, or else the client would be destroyed
 293  * when the last task releases it.
 294  */
 295 int
 296 rpc_shutdown_client(struct rpc_clnt *clnt)
 297 {
 298         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
 299                         clnt->cl_protname, clnt->cl_server,
 300                         atomic_read(&clnt->cl_users));
 301
 302         while (atomic_read(&clnt->cl_users) > 0) {
 303                 /* Don't let rpc_release_client destroy us */
 304                 clnt->cl_oneshot = 0;
 305                 clnt->cl_dead = 0;
 306                 rpc_killall_tasks(clnt);
 307                 wait_event_timeout(destroy_wait,
 308                         !atomic_read(&clnt->cl_users), 1*HZ);
 309         }
 310
 311         if (atomic_read(&clnt->cl_users) < 0) {
 312                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 313                                 clnt, atomic_read(&clnt->cl_users));
 314 #ifdef RPC_DEBUG
 315                 rpc_show_tasks();
 316 #endif
 317                 BUG();
 318         }
 319
 320         return rpc_destroy_client(clnt);
 321 }
 322
 323 /*
 324  * Delete an RPC client
 325  */
 326 int
 327 rpc_destroy_client(struct rpc_clnt *clnt)
 328 {
 329         if (!atomic_dec_and_test(&clnt->cl_count))
 330                 return 1;
 331         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 332
 333         dprintk("RPC: destroying %s client for %s\n",
 334                         clnt->cl_protname, clnt->cl_server);
 335         if (clnt->cl_auth) {
 336                 rpcauth_destroy(clnt->cl_auth);
 337                 clnt->cl_auth = NULL;
 338         }
 339         if (clnt->cl_parent != clnt) {
 340                 if (!IS_ERR(clnt->cl_dentry))
 341                         dput(clnt->cl_dentry);
 342                 rpc_destroy_client(clnt->cl_parent);
 343                 goto out_free;
 344         }
 345         if (!IS_ERR(clnt->cl_dentry)) {
 346                 rpc_rmdir(clnt->cl_dentry);
 347                 rpc_put_mount();
 348         }
 349         if (clnt->cl_server != clnt->cl_inline_name)
 350                 kfree(clnt->cl_server);
 351 out_free:
 352         rpc_free_iostats(clnt->cl_metrics);
 353         clnt->cl_metrics = NULL;
 354         xprt_put(clnt->cl_xprt);
 355         kfree(clnt);
 356         return 0;
 357 }
 358
 359 /*
 360  * Release an RPC client
 361  */
 362 void
 363 rpc_release_client(struct rpc_clnt *clnt)
 364 {
 365         dprintk("RPC:      rpc_release_client(%p, %d)\n",
 366                                 clnt, atomic_read(&clnt->cl_users));
 367
 368         if (!atomic_dec_and_test(&clnt->cl_users))
 369                 return;
 370         wake_up(&destroy_wait);
 371         if (clnt->cl_oneshot || clnt->cl_dead)
 372                 rpc_destroy_client(clnt);
 373 }
 374
 375 /**
 376  * rpc_bind_new_program - bind a new RPC program to an existing client
 377  * @old - old rpc_client
 378  * @program - rpc program to set
 379  * @vers - rpc program version
 380  *
 381  * Clones the rpc client and sets up a new RPC program. This is mainly
 382  * of use for enabling different RPC programs to share the same transport.
 383  * The Sun NFSv2/v3 ACL protocol can do this.
 384  */
 385 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 386                                       struct rpc_program *program,
 387                                       int vers)
 388 {
 389         struct rpc_clnt *clnt;
 390         struct rpc_version *version;
 391         int err;
 392
 393         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 394         version = program->version[vers];
 395         clnt = rpc_clone_client(old);
 396         if (IS_ERR(clnt))
 397                 goto out;
 398         clnt->cl_procinfo = version->procs;
 399         clnt->cl_maxproc  = version->nrprocs;
 400         clnt->cl_protname = program->name;
 401         clnt->cl_prog     = program->number;
 402         clnt->cl_vers     = version->number;
 403         clnt->cl_stats    = program->stats;
 404         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 405         if (err != 0) {
 406                 rpc_shutdown_client(clnt);
 407                 clnt = ERR_PTR(err);
 408         }
 409 out:
 410         return clnt;
 411 }
 412
 413 /*
 414  * Default callback for async RPC calls
 415  */
 416 static void
 417 rpc_default_callback(struct rpc_task *task, void *data)
 418 {
 419 }
 420
 421 static const struct rpc_call_ops rpc_default_ops = {
 422         .rpc_call_done = rpc_default_callback,
 423 };
 424
 425 /*
 426  *      Export the signal mask handling for synchronous code that
 427  *      sleeps on RPC calls
 428  */
 429 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 430
 431 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 432 {
 433         unsigned long   sigallow = sigmask(SIGKILL);
 434         sigset_t sigmask;
 435
 436         /* Block all signals except those listed in sigallow */
 437         if (intr)
 438                 sigallow |= RPC_INTR_SIGNALS;
 439         siginitsetinv(&sigmask, sigallow);
 440         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 441 }
 442
 443 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 444 {
 445         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 446 }
 447
 448 static inline void rpc_restore_sigmask(sigset_t *oldset)
 449 {
 450         sigprocmask(SIG_SETMASK, oldset, NULL);
 451 }
 452
 453 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 454 {
 455         rpc_save_sigmask(oldset, clnt->cl_intr);
 456 }
 457
 458 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 459 {
 460         rpc_restore_sigmask(oldset);
 461 }
 462
 463 /*
 464  * New rpc_call implementation
 465  */
 466 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 467 {
 468         struct rpc_task *task;
 469         sigset_t        oldset;
 470         int             status;
 471
 472         /* If this client is slain all further I/O fails */
 473         if (clnt->cl_dead)
 474                 return -EIO;
 475
 476         BUG_ON(flags & RPC_TASK_ASYNC);
 477
 478         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 479         if (task == NULL)
 480                 return -ENOMEM;
 481
 482         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 483         rpc_task_sigmask(task, &oldset);
 484
 485         rpc_call_setup(task, msg, 0);
 486
 487         /* Set up the call info struct and execute the task */
 488         status = task->tk_status;
 489         if (status != 0) {
 490                 rpc_release_task(task);
 491                 goto out;
 492         }
 493         atomic_inc(&task->tk_count);
 494         status = rpc_execute(task);
 495         if (status == 0)
 496                 status = task->tk_status;
 497         rpc_put_task(task);
 498 out:
 499         rpc_restore_sigmask(&oldset);
 500         return status;
 501 }
 502
 503 /*
 504  * New rpc_call implementation
 505  */
 506 int
 507 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 508                const struct rpc_call_ops *tk_ops, void *data)
 509 {
 510         struct rpc_task *task;
 511         sigset_t        oldset;
 512         int             status;
 513
 514         /* If this client is slain all further I/O fails */
 515         status = -EIO;
 516         if (clnt->cl_dead)
 517                 goto out_release;
 518
 519         flags |= RPC_TASK_ASYNC;
 520
 521         /* Create/initialize a new RPC task */
 522         status = -ENOMEM;
 523         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 524                 goto out_release;
 525
 526         /* Mask signals on GSS_AUTH upcalls */
 527         rpc_task_sigmask(task, &oldset);
 528
 529         rpc_call_setup(task, msg, 0);
 530
 531         /* Set up the call info struct and execute the task */
 532         status = task->tk_status;
 533         if (status == 0)
 534                 rpc_execute(task);
 535         else
 536                 rpc_release_task(task);
 537
 538         rpc_restore_sigmask(&oldset);
 539         return status;
 540 out_release:
 541         if (tk_ops->rpc_release != NULL)
 542                 tk_ops->rpc_release(data);
 543         return status;
 544 }
 545
 546
 547 void
 548 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 549 {
 550         task->tk_msg   = *msg;
 551         task->tk_flags |= flags;
 552         /* Bind the user cred */
 553         if (task->tk_msg.rpc_cred != NULL)
 554                 rpcauth_holdcred(task);
 555         else
 556                 rpcauth_bindcred(task);
 557
 558         if (task->tk_status == 0)
 559                 task->tk_action = call_start;
 560         else
 561                 task->tk_action = rpc_exit_task;
 562 }
 563
 564 /**
 565  * rpc_peeraddr - extract remote peer address from clnt's xprt
 566  * @clnt: RPC client structure
 567  * @buf: target buffer
 568  * @size: length of target buffer
 569  *
 570  * Returns the number of bytes that are actually in the stored address.
 571  */
 572 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 573 {
 574         size_t bytes;
 575         struct rpc_xprt *xprt = clnt->cl_xprt;
 576
 577         bytes = sizeof(xprt->addr);
 578         if (bytes > bufsize)
 579                 bytes = bufsize;
 580         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 581         return xprt->addrlen;
 582 }
 583 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 584
 585 /**
 586  * rpc_peeraddr2str - return remote peer address in printable format
 587  * @clnt: RPC client structure
 588  * @format: address format
 589  *
 590  */
 591 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 592 {
 593         struct rpc_xprt *xprt = clnt->cl_xprt;
 594         return xprt->ops->print_addr(xprt, format);
 595 }
 596 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 597
 598 void
 599 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 600 {
 601         struct rpc_xprt *xprt = clnt->cl_xprt;
 602         if (xprt->ops->set_buffer_size)
 603                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 604 }
 605
 606 /*
 607  * Return size of largest payload RPC client can support, in bytes
 608  *
 609  * For stream transports, this is one RPC record fragment (see RFC
 610  * 1831), as we don't support multi-record requests yet.  For datagram
 611  * transports, this is the size of an IP packet minus the IP, UDP, and
 612  * RPC header sizes.
 613  */
 614 size_t rpc_max_payload(struct rpc_clnt *clnt)
 615 {
 616         return clnt->cl_xprt->max_payload;
 617 }
 618 EXPORT_SYMBOL_GPL(rpc_max_payload);
 619
 620 /**
 621  * rpc_force_rebind - force transport to check that remote port is unchanged
 622  * @clnt: client to rebind
 623  *
 624  */
 625 void rpc_force_rebind(struct rpc_clnt *clnt)
 626 {
 627         if (clnt->cl_autobind)
 628                 xprt_clear_bound(clnt->cl_xprt);
 629 }
 630 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 631
 632 /*
 633  * Restart an (async) RPC call. Usually called from within the
 634  * exit handler.
 635  */
 636 void
 637 rpc_restart_call(struct rpc_task *task)
 638 {
 639         if (RPC_ASSASSINATED(task))
 640                 return;
 641
 642         task->tk_action = call_start;
 643 }
 644
 645 /*
 646  * 0.  Initial state
 647  *
 648  *     Other FSM states can be visited zero or more times, but
 649  *     this state is visited exactly once for each RPC.
 650  */
 651 static void
 652 call_start(struct rpc_task *task)
 653 {
 654         struct rpc_clnt *clnt = task->tk_client;
 655
 656         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 657                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 658                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 659
 660         /* Increment call count */
 661         task->tk_msg.rpc_proc->p_count++;
 662         clnt->cl_stats->rpccnt++;
 663         task->tk_action = call_reserve;
 664 }
 665
 666 /*
 667  * 1.   Reserve an RPC call slot
 668  */
 669 static void
 670 call_reserve(struct rpc_task *task)
 671 {
 672         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 673
 674         if (!rpcauth_uptodatecred(task)) {
 675                 task->tk_action = call_refresh;
 676                 return;
 677         }
 678
 679         task->tk_status  = 0;
 680         task->tk_action  = call_reserveresult;
 681         xprt_reserve(task);
 682 }
 683
 684 /*
 685  * 1b.  Grok the result of xprt_reserve()
 686  */
 687 static void
 688 call_reserveresult(struct rpc_task *task)
 689 {
 690         int status = task->tk_status;
 691
 692         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 693                                 task->tk_pid, task->tk_status);
 694
 695         /*
 696          * After a call to xprt_reserve(), we must have either
 697          * a request slot or else an error status.
 698          */
 699         task->tk_status = 0;
 700         if (status >= 0) {
 701                 if (task->tk_rqstp) {
 702                         task->tk_action = call_allocate;
 703                         return;
 704                 }
 705
 706                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 707                                 __FUNCTION__, status);
 708                 rpc_exit(task, -EIO);
 709                 return;
 710         }
 711
 712         /*
 713          * Even though there was an error, we may have acquired
 714          * a request slot somehow.  Make sure not to leak it.
 715          */
 716         if (task->tk_rqstp) {
 717                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 718                                 __FUNCTION__, status);
 719                 xprt_release(task);
 720         }
 721
 722         switch (status) {
 723         case -EAGAIN:   /* woken up; retry */
 724                 task->tk_action = call_reserve;
 725                 return;
 726         case -EIO:      /* probably a shutdown */
 727                 break;
 728         default:
 729                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 730                                 __FUNCTION__, status);
 731                 break;
 732         }
 733         rpc_exit(task, status);
 734 }
 735
 736 /*
 737  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 738  *      (Note: buffer memory is freed in xprt_release).
 739  */
 740 static void
 741 call_allocate(struct rpc_task *task)
 742 {
 743         struct rpc_rqst *req = task->tk_rqstp;
 744         struct rpc_xprt *xprt = task->tk_xprt;
 745         unsigned int    bufsiz;
 746
 747         dprintk("RPC: %4d call_allocate (status %d)\n",
 748                                 task->tk_pid, task->tk_status);
 749         task->tk_action = call_bind;
 750         if (req->rq_buffer)
 751                 return;
 752
 753         /* FIXME: compute buffer requirements more exactly using
 754          * auth->au_wslack */
 755         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 756
 757         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 758                 return;
 759         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 760
 761         if (RPC_IS_ASYNC(task) || !signalled()) {
 762                 xprt_release(task);
 763                 task->tk_action = call_reserve;
 764                 rpc_delay(task, HZ>>4);
 765                 return;
 766         }
 767
 768         rpc_exit(task, -ERESTARTSYS);
 769 }
 770
 771 static inline int
 772 rpc_task_need_encode(struct rpc_task *task)
 773 {
 774         return task->tk_rqstp->rq_snd_buf.len == 0;
 775 }
 776
 777 static inline void
 778 rpc_task_force_reencode(struct rpc_task *task)
 779 {
 780         task->tk_rqstp->rq_snd_buf.len = 0;
 781 }
 782
 783 /*
 784  * 3.   Encode arguments of an RPC call
 785  */
 786 static void
 787 call_encode(struct rpc_task *task)
 788 {
 789         struct rpc_rqst *req = task->tk_rqstp;
 790         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 791         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 792         unsigned int    bufsiz;
 793         kxdrproc_t      encode;
 794         __be32          *p;
 795
 796         dprintk("RPC: %4d call_encode (status %d)\n",
 797                                 task->tk_pid, task->tk_status);
 798
 799         /* Default buffer setup */
 800         bufsiz = req->rq_bufsize >> 1;
 801         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 802         sndbuf->head[0].iov_len  = bufsiz;
 803         sndbuf->tail[0].iov_len  = 0;
 804         sndbuf->page_len         = 0;
 805         sndbuf->len              = 0;
 806         sndbuf->buflen           = bufsiz;
 807         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 808         rcvbuf->head[0].iov_len  = bufsiz;
 809         rcvbuf->tail[0].iov_len  = 0;
 810         rcvbuf->page_len         = 0;
 811         rcvbuf->len              = 0;
 812         rcvbuf->buflen           = bufsiz;
 813
 814         /* Encode header and provided arguments */
 815         encode = task->tk_msg.rpc_proc->p_encode;
 816         if (!(p = call_header(task))) {
 817                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 818                 rpc_exit(task, -EIO);
 819                 return;
 820         }
 821         if (encode == NULL)
 822                 return;
 823
 824         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 825                         task->tk_msg.rpc_argp);
 826         if (task->tk_status == -ENOMEM) {
 827                 /* XXX: Is this sane? */
 828                 rpc_delay(task, 3*HZ);
 829                 task->tk_status = -EAGAIN;
 830         }
 831 }
 832
 833 /*
 834  * 4.   Get the server port number if not yet set
 835  */
 836 static void
 837 call_bind(struct rpc_task *task)
 838 {
 839         struct rpc_xprt *xprt = task->tk_xprt;
 840
 841         dprintk("RPC: %4d call_bind (status %d)\n",
 842                                 task->tk_pid, task->tk_status);
 843
 844         task->tk_action = call_connect;
 845         if (!xprt_bound(xprt)) {
 846                 task->tk_action = call_bind_status;
 847                 task->tk_timeout = xprt->bind_timeout;
 848                 xprt->ops->rpcbind(task);
 849         }
 850 }
 851
 852 /*
 853  * 4a.  Sort out bind result
 854  */
 855 static void
 856 call_bind_status(struct rpc_task *task)
 857 {
 858         int status = -EACCES;
 859
 860         if (task->tk_status >= 0) {
 861                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 862                                         task->tk_pid, task->tk_status);
 863                 task->tk_status = 0;
 864                 task->tk_action = call_connect;
 865                 return;
 866         }
 867
 868         switch (task->tk_status) {
 869         case -EACCES:
 870                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
 871                                 task->tk_pid);
 872                 rpc_delay(task, 3*HZ);
 873                 goto retry_timeout;
 874         case -ETIMEDOUT:
 875                 dprintk("RPC: %4d rpcbind request timed out\n",
 876                                 task->tk_pid);
 877                 goto retry_timeout;
 878         case -EPFNOSUPPORT:
 879                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 880                                 task->tk_pid);
 881                 break;
 882         case -EPROTONOSUPPORT:
 883                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 884                                 task->tk_pid);
 885                 break;
 886         default:
 887                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 888                                 task->tk_pid, -task->tk_status);
 889                 status = -EIO;
 890         }
 891
 892         rpc_exit(task, status);
 893         return;
 894
 895 retry_timeout:
 896         task->tk_action = call_timeout;
 897 }
 898
 899 /*
 900  * 4b.  Connect to the RPC server
 901  */
 902 static void
 903 call_connect(struct rpc_task *task)
 904 {
 905         struct rpc_xprt *xprt = task->tk_xprt;
 906
 907         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 908                         task->tk_pid, xprt,
 909                         (xprt_connected(xprt) ? "is" : "is not"));
 910
 911         task->tk_action = call_transmit;
 912         if (!xprt_connected(xprt)) {
 913                 task->tk_action = call_connect_status;
 914                 if (task->tk_status < 0)
 915                         return;
 916                 xprt_connect(task);
 917         }
 918 }
 919
 920 /*
 921  * 4c.  Sort out connect result
 922  */
 923 static void
 924 call_connect_status(struct rpc_task *task)
 925 {
 926         struct rpc_clnt *clnt = task->tk_client;
 927         int status = task->tk_status;
 928
 929         dprintk("RPC: %5u call_connect_status (status %d)\n",
 930                                 task->tk_pid, task->tk_status);
 931
 932         task->tk_status = 0;
 933         if (status >= 0) {
 934                 clnt->cl_stats->netreconn++;
 935                 task->tk_action = call_transmit;
 936                 return;
 937         }
 938
 939         /* Something failed: remote service port may have changed */
 940         rpc_force_rebind(clnt);
 941
 942         switch (status) {
 943         case -ENOTCONN:
 944         case -EAGAIN:
 945                 task->tk_action = call_bind;
 946                 if (!RPC_IS_SOFT(task))
 947                         return;
 948                 /* if soft mounted, test if we've timed out */
 949         case -ETIMEDOUT:
 950                 task->tk_action = call_timeout;
 951                 return;
 952         }
 953         rpc_exit(task, -EIO);
 954 }
 955
 956 /*
 957  * 5.   Transmit the RPC request, and wait for reply
 958  */
 959 static void
 960 call_transmit(struct rpc_task *task)
 961 {
 962         dprintk("RPC: %4d call_transmit (status %d)\n",
 963                                 task->tk_pid, task->tk_status);
 964
 965         task->tk_action = call_status;
 966         if (task->tk_status < 0)
 967                 return;
 968         task->tk_status = xprt_prepare_transmit(task);
 969         if (task->tk_status != 0)
 970                 return;
 971         task->tk_action = call_transmit_status;
 972         /* Encode here so that rpcsec_gss can use correct sequence number. */
 973         if (rpc_task_need_encode(task)) {
 974                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 975                 call_encode(task);
 976                 /* Did the encode result in an error condition? */
 977                 if (task->tk_status != 0)
 978                         return;
 979         }
 980         xprt_transmit(task);
 981         if (task->tk_status < 0)
 982                 return;
 983         /*
 984          * On success, ensure that we call xprt_end_transmit() before sleeping
 985          * in order to allow access to the socket to other RPC requests.
 986          */
 987         call_transmit_status(task);
 988         if (task->tk_msg.rpc_proc->p_decode != NULL)
 989                 return;
 990         task->tk_action = rpc_exit_task;
 991         rpc_wake_up_task(task);
 992 }
 993
 994 /*
 995  * 5a.  Handle cleanup after a transmission
 996  */
 997 static void
 998 call_transmit_status(struct rpc_task *task)
 999 {
1000         task->tk_action = call_status;
1001         /*
1002          * Special case: if we've been waiting on the socket's write_space()
1003          * callback, then don't call xprt_end_transmit().
1004          */
1005         if (task->tk_status == -EAGAIN)
1006                 return;
1007         xprt_end_transmit(task);
1008         rpc_task_force_reencode(task);
1009 }
1010
1011 /*
1012  * 6.   Sort out the RPC call status
1013  */
1014 static void
1015 call_status(struct rpc_task *task)
1016 {
1017         struct rpc_clnt *clnt = task->tk_client;
1018         struct rpc_rqst *req = task->tk_rqstp;
1019         int             status;
1020
1021         if (req->rq_received > 0 && !req->rq_bytes_sent)
1022                 task->tk_status = req->rq_received;
1023
1024         dprintk("RPC: %4d call_status (status %d)\n",
1025                                 task->tk_pid, task->tk_status);
1026
1027         status = task->tk_status;
1028         if (status >= 0) {
1029                 task->tk_action = call_decode;
1030                 return;
1031         }
1032
1033         task->tk_status = 0;
1034         switch(status) {
1035         case -EHOSTDOWN:
1036         case -EHOSTUNREACH:
1037         case -ENETUNREACH:
1038                 /*
1039                  * Delay any retries for 3 seconds, then handle as if it
1040                  * were a timeout.
1041                  */
1042                 rpc_delay(task, 3*HZ);
1043         case -ETIMEDOUT:
1044                 task->tk_action = call_timeout;
1045                 break;
1046         case -ECONNREFUSED:
1047         case -ENOTCONN:
1048                 rpc_force_rebind(clnt);
1049                 task->tk_action = call_bind;
1050                 break;
1051         case -EAGAIN:
1052                 task->tk_action = call_transmit;
1053                 break;
1054         case -EIO:
1055                 /* shutdown or soft timeout */
1056                 rpc_exit(task, status);
1057                 break;
1058         default:
1059                 printk("%s: RPC call returned error %d\n",
1060                                clnt->cl_protname, -status);
1061                 rpc_exit(task, status);
1062         }
1063 }
1064
1065 /*
1066  * 6a.  Handle RPC timeout
1067  *      We do not release the request slot, so we keep using the
1068  *      same XID for all retransmits.
1069  */
1070 static void
1071 call_timeout(struct rpc_task *task)
1072 {
1073         struct rpc_clnt *clnt = task->tk_client;
1074
1075         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1076                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1077                 goto retry;
1078         }
1079
1080         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1081         task->tk_timeouts++;
1082
1083         if (RPC_IS_SOFT(task)) {
1084                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1085                                 clnt->cl_protname, clnt->cl_server);
1086                 rpc_exit(task, -EIO);
1087                 return;
1088         }
1089
1090         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1091                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1092                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1093                         clnt->cl_protname, clnt->cl_server);
1094         }
1095         rpc_force_rebind(clnt);
1096
1097 retry:
1098         clnt->cl_stats->rpcretrans++;
1099         task->tk_action = call_bind;
1100         task->tk_status = 0;
1101 }
1102
1103 /*
1104  * 7.   Decode the RPC reply
1105  */
1106 static void
1107 call_decode(struct rpc_task *task)
1108 {
1109         struct rpc_clnt *clnt = task->tk_client;
1110         struct rpc_rqst *req = task->tk_rqstp;
1111         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1112         __be32          *p;
1113
1114         dprintk("RPC: %4d call_decode (status %d)\n",
1115                                 task->tk_pid, task->tk_status);
1116
1117         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1118                 printk(KERN_NOTICE "%s: server %s OK\n",
1119                         clnt->cl_protname, clnt->cl_server);
1120                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1121         }
1122
1123         if (task->tk_status < 12) {
1124                 if (!RPC_IS_SOFT(task)) {
1125                         task->tk_action = call_bind;
1126                         clnt->cl_stats->rpcretrans++;
1127                         goto out_retry;
1128                 }
1129                 dprintk("%s: too small RPC reply size (%d bytes)\n",
1130                         clnt->cl_protname, task->tk_status);
1131                 task->tk_action = call_timeout;
1132                 goto out_retry;
1133         }
1134
1135         /*
1136          * Ensure that we see all writes made by xprt_complete_rqst()
1137          * before it changed req->rq_received.
1138          */
1139         smp_rmb();
1140         req->rq_rcv_buf.len = req->rq_private_buf.len;
1141
1142         /* Check that the softirq receive buffer is valid */
1143         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1144                                 sizeof(req->rq_rcv_buf)) != 0);
1145
1146         /* Verify the RPC header */
1147         p = call_verify(task);
1148         if (IS_ERR(p)) {
1149                 if (p == ERR_PTR(-EAGAIN))
1150                         goto out_retry;
1151                 return;
1152         }
1153
1154         task->tk_action = rpc_exit_task;
1155
1156         if (decode)
1157                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1158                                                       task->tk_msg.rpc_resp);
1159         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1160                                         task->tk_status);
1161         return;
1162 out_retry:
1163         req->rq_received = req->rq_private_buf.len = 0;
1164         task->tk_status = 0;
1165 }
1166
1167 /*
1168  * 8.   Refresh the credentials if rejected by the server
1169  */
1170 static void
1171 call_refresh(struct rpc_task *task)
1172 {
1173         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1174
1175         xprt_release(task);     /* Must do to obtain new XID */
1176         task->tk_action = call_refreshresult;
1177         task->tk_status = 0;
1178         task->tk_client->cl_stats->rpcauthrefresh++;
1179         rpcauth_refreshcred(task);
1180 }
1181
1182 /*
1183  * 8a.  Process the results of a credential refresh
1184  */
1185 static void
1186 call_refreshresult(struct rpc_task *task)
1187 {
1188         int status = task->tk_status;
1189         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1190                                 task->tk_pid, task->tk_status);
1191
1192         task->tk_status = 0;
1193         task->tk_action = call_reserve;
1194         if (status >= 0 && rpcauth_uptodatecred(task))
1195                 return;
1196         if (status == -EACCES) {
1197                 rpc_exit(task, -EACCES);
1198                 return;
1199         }
1200         task->tk_action = call_refresh;
1201         if (status != -ETIMEDOUT)
1202                 rpc_delay(task, 3*HZ);
1203         return;
1204 }
1205
1206 /*
1207  * Call header serialization
1208  */
1209 static __be32 *
1210 call_header(struct rpc_task *task)
1211 {
1212         struct rpc_clnt *clnt = task->tk_client;
1213         struct rpc_rqst *req = task->tk_rqstp;
1214         __be32          *p = req->rq_svec[0].iov_base;
1215
1216         /* FIXME: check buffer size? */
1217
1218         p = xprt_skip_transport_header(task->tk_xprt, p);
1219         *p++ = req->rq_xid;             /* XID */
1220         *p++ = htonl(RPC_CALL);         /* CALL */
1221         *p++ = htonl(RPC_VERSION);      /* RPC version */
1222         *p++ = htonl(clnt->cl_prog);    /* program number */
1223         *p++ = htonl(clnt->cl_vers);    /* program version */
1224         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1225         p = rpcauth_marshcred(task, p);
1226         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1227         return p;
1228 }
1229
1230 /*
1231  * Reply header verification
1232  */
1233 static __be32 *
1234 call_verify(struct rpc_task *task)
1235 {
1236         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1237         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1238         __be32  *p = iov->iov_base;
1239         u32 n;
1240         int error = -EACCES;
1241
1242         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1243                 /* RFC-1014 says that the representation of XDR data must be a
1244                  * multiple of four bytes
1245                  * - if it isn't pointer subtraction in the NFS client may give
1246                  *   undefined results
1247                  */
1248                 printk(KERN_WARNING
1249                        "call_verify: XDR representation not a multiple of"
1250                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1251                 goto out_eio;
1252         }
1253         if ((len -= 3) < 0)
1254                 goto out_overflow;
1255         p += 1; /* skip XID */
1256
1257         if ((n = ntohl(*p++)) != RPC_REPLY) {
1258                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1259                 goto out_garbage;
1260         }
1261         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1262                 if (--len < 0)
1263                         goto out_overflow;
1264                 switch ((n = ntohl(*p++))) {
1265                         case RPC_AUTH_ERROR:
1266                                 break;
1267                         case RPC_MISMATCH:
1268                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1269                                 error = -EPROTONOSUPPORT;
1270                                 goto out_err;
1271                         default:
1272                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1273                                 goto out_eio;
1274                 }
1275                 if (--len < 0)
1276                         goto out_overflow;
1277                 switch ((n = ntohl(*p++))) {
1278                 case RPC_AUTH_REJECTEDCRED:
1279                 case RPC_AUTH_REJECTEDVERF:
1280                 case RPCSEC_GSS_CREDPROBLEM:
1281                 case RPCSEC_GSS_CTXPROBLEM:
1282                         if (!task->tk_cred_retry)
1283                                 break;
1284                         task->tk_cred_retry--;
1285                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1286                                                         task->tk_pid);
1287                         rpcauth_invalcred(task);
1288                         task->tk_action = call_refresh;
1289                         goto out_retry;
1290                 case RPC_AUTH_BADCRED:
1291                 case RPC_AUTH_BADVERF:
1292                         /* possibly garbled cred/verf? */
1293                         if (!task->tk_garb_retry)
1294                                 break;
1295                         task->tk_garb_retry--;
1296                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1297                                                         task->tk_pid);
1298                         task->tk_action = call_bind;
1299                         goto out_retry;
1300                 case RPC_AUTH_TOOWEAK:
1301                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1302                                "authentication.\n", task->tk_client->cl_server);
1303                         break;
1304                 default:
1305                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1306                         error = -EIO;
1307                 }
1308                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1309                                                 task->tk_pid, n);
1310                 goto out_err;
1311         }
1312         if (!(p = rpcauth_checkverf(task, p))) {
1313                 printk(KERN_WARNING "call_verify: auth check failed\n");
1314                 goto out_garbage;               /* bad verifier, retry */
1315         }
1316         len = p - (__be32 *)iov->iov_base - 1;
1317         if (len < 0)
1318                 goto out_overflow;
1319         switch ((n = ntohl(*p++))) {
1320         case RPC_SUCCESS:
1321                 return p;
1322         case RPC_PROG_UNAVAIL:
1323                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1324                                 (unsigned int)task->tk_client->cl_prog,
1325                                 task->tk_client->cl_server);
1326                 error = -EPFNOSUPPORT;
1327                 goto out_err;
1328         case RPC_PROG_MISMATCH:
1329                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1330                                 (unsigned int)task->tk_client->cl_prog,
1331                                 (unsigned int)task->tk_client->cl_vers,
1332                                 task->tk_client->cl_server);
1333                 error = -EPROTONOSUPPORT;
1334                 goto out_err;
1335         case RPC_PROC_UNAVAIL:
1336                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1337                                 task->tk_msg.rpc_proc,
1338                                 task->tk_client->cl_prog,
1339                                 task->tk_client->cl_vers,
1340                                 task->tk_client->cl_server);
1341                 error = -EOPNOTSUPP;
1342                 goto out_err;
1343         case RPC_GARBAGE_ARGS:
1344                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1345                 break;                  /* retry */
1346         default:
1347                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1348                 /* Also retry */
1349         }
1350
1351 out_garbage:
1352         task->tk_client->cl_stats->rpcgarbage++;
1353         if (task->tk_garb_retry) {
1354                 task->tk_garb_retry--;
1355                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1356                 task->tk_action = call_bind;
1357 out_retry:
1358                 return ERR_PTR(-EAGAIN);
1359         }
1360         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1361 out_eio:
1362         error = -EIO;
1363 out_err:
1364         rpc_exit(task, error);
1365         return ERR_PTR(error);
1366 out_overflow:
1367         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1368         goto out_garbage;
1369 }
1370
1371 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1372 {
1373         return 0;
1374 }
1375
1376 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1377 {
1378         return 0;
1379 }
1380
1381 static struct rpc_procinfo rpcproc_null = {
1382         .p_encode = rpcproc_encode_null,
1383         .p_decode = rpcproc_decode_null,
1384 };
1385
1386 int rpc_ping(struct rpc_clnt *clnt, int flags)
1387 {
1388         struct rpc_message msg = {
1389                 .rpc_proc = &rpcproc_null,
1390         };
1391         int err;
1392         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1393         err = rpc_call_sync(clnt, &msg, flags);
1394         put_rpccred(msg.rpc_cred);
1395         return err;
1396 }