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