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
 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(utsname()->nodename);
 165         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 166                 clnt->cl_nodelen = UNX_MAXNODENAME;
 167         memcpy(clnt->cl_nodename, 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 = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 257         if (!new)
 258                 goto out_no_clnt;
 259         atomic_set(&new->cl_count, 1);
 260         atomic_set(&new->cl_users, 0);
 261         new->cl_parent = clnt;
 262         atomic_inc(&clnt->cl_count);
 263         new->cl_xprt = xprt_get(clnt->cl_xprt);
 264         /* Turn off autobind on clones */
 265         new->cl_autobind = 0;
 266         new->cl_oneshot = 0;
 267         new->cl_dead = 0;
 268         if (!IS_ERR(new->cl_dentry))
 269                 dget(new->cl_dentry);
 270         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 271         if (new->cl_auth)
 272                 atomic_inc(&new->cl_auth->au_count);
 273         new->cl_metrics = rpc_alloc_iostats(clnt);
 274         return new;
 275 out_no_clnt:
 276         printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
 277         return ERR_PTR(-ENOMEM);
 278 }
 279
 280 /*
 281  * Properly shut down an RPC client, terminating all outstanding
 282  * requests. Note that we must be certain that cl_oneshot and
 283  * cl_dead are cleared, or else the client would be destroyed
 284  * when the last task releases it.
 285  */
 286 int
 287 rpc_shutdown_client(struct rpc_clnt *clnt)
 288 {
 289         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
 290                         clnt->cl_protname, clnt->cl_server,
 291                         atomic_read(&clnt->cl_users));
 292
 293         while (atomic_read(&clnt->cl_users) > 0) {
 294                 /* Don't let rpc_release_client destroy us */
 295                 clnt->cl_oneshot = 0;
 296                 clnt->cl_dead = 0;
 297                 rpc_killall_tasks(clnt);
 298                 wait_event_timeout(destroy_wait,
 299                         !atomic_read(&clnt->cl_users), 1*HZ);
 300         }
 301
 302         if (atomic_read(&clnt->cl_users) < 0) {
 303                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 304                                 clnt, atomic_read(&clnt->cl_users));
 305 #ifdef RPC_DEBUG
 306                 rpc_show_tasks();
 307 #endif
 308                 BUG();
 309         }
 310
 311         return rpc_destroy_client(clnt);
 312 }
 313
 314 /*
 315  * Delete an RPC client
 316  */
 317 int
 318 rpc_destroy_client(struct rpc_clnt *clnt)
 319 {
 320         if (!atomic_dec_and_test(&clnt->cl_count))
 321                 return 1;
 322         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 323
 324         dprintk("RPC: destroying %s client for %s\n",
 325                         clnt->cl_protname, clnt->cl_server);
 326         if (clnt->cl_auth) {
 327                 rpcauth_destroy(clnt->cl_auth);
 328                 clnt->cl_auth = NULL;
 329         }
 330         if (clnt->cl_parent != clnt) {
 331                 if (!IS_ERR(clnt->cl_dentry))
 332                         dput(clnt->cl_dentry);
 333                 rpc_destroy_client(clnt->cl_parent);
 334                 goto out_free;
 335         }
 336         if (!IS_ERR(clnt->cl_dentry)) {
 337                 rpc_rmdir(clnt->cl_dentry);
 338                 rpc_put_mount();
 339         }
 340         if (clnt->cl_server != clnt->cl_inline_name)
 341                 kfree(clnt->cl_server);
 342 out_free:
 343         rpc_free_iostats(clnt->cl_metrics);
 344         clnt->cl_metrics = NULL;
 345         xprt_put(clnt->cl_xprt);
 346         kfree(clnt);
 347         return 0;
 348 }
 349
 350 /*
 351  * Release an RPC client
 352  */
 353 void
 354 rpc_release_client(struct rpc_clnt *clnt)
 355 {
 356         dprintk("RPC:      rpc_release_client(%p, %d)\n",
 357                                 clnt, atomic_read(&clnt->cl_users));
 358
 359         if (!atomic_dec_and_test(&clnt->cl_users))
 360                 return;
 361         wake_up(&destroy_wait);
 362         if (clnt->cl_oneshot || clnt->cl_dead)
 363                 rpc_destroy_client(clnt);
 364 }
 365
 366 /**
 367  * rpc_bind_new_program - bind a new RPC program to an existing client
 368  * @old - old rpc_client
 369  * @program - rpc program to set
 370  * @vers - rpc program version
 371  *
 372  * Clones the rpc client and sets up a new RPC program. This is mainly
 373  * of use for enabling different RPC programs to share the same transport.
 374  * The Sun NFSv2/v3 ACL protocol can do this.
 375  */
 376 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 377                                       struct rpc_program *program,
 378                                       int vers)
 379 {
 380         struct rpc_clnt *clnt;
 381         struct rpc_version *version;
 382         int err;
 383
 384         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 385         version = program->version[vers];
 386         clnt = rpc_clone_client(old);
 387         if (IS_ERR(clnt))
 388                 goto out;
 389         clnt->cl_procinfo = version->procs;
 390         clnt->cl_maxproc  = version->nrprocs;
 391         clnt->cl_protname = program->name;
 392         clnt->cl_prog     = program->number;
 393         clnt->cl_vers     = version->number;
 394         clnt->cl_stats    = program->stats;
 395         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 396         if (err != 0) {
 397                 rpc_shutdown_client(clnt);
 398                 clnt = ERR_PTR(err);
 399         }
 400 out:
 401         return clnt;
 402 }
 403
 404 /*
 405  * Default callback for async RPC calls
 406  */
 407 static void
 408 rpc_default_callback(struct rpc_task *task, void *data)
 409 {
 410 }
 411
 412 static const struct rpc_call_ops rpc_default_ops = {
 413         .rpc_call_done = rpc_default_callback,
 414 };
 415
 416 /*
 417  *      Export the signal mask handling for synchronous code that
 418  *      sleeps on RPC calls
 419  */
 420 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 421
 422 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 423 {
 424         unsigned long   sigallow = sigmask(SIGKILL);
 425         sigset_t sigmask;
 426
 427         /* Block all signals except those listed in sigallow */
 428         if (intr)
 429                 sigallow |= RPC_INTR_SIGNALS;
 430         siginitsetinv(&sigmask, sigallow);
 431         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 432 }
 433
 434 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 435 {
 436         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 437 }
 438
 439 static inline void rpc_restore_sigmask(sigset_t *oldset)
 440 {
 441         sigprocmask(SIG_SETMASK, oldset, NULL);
 442 }
 443
 444 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 445 {
 446         rpc_save_sigmask(oldset, clnt->cl_intr);
 447 }
 448
 449 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 450 {
 451         rpc_restore_sigmask(oldset);
 452 }
 453
 454 /*
 455  * New rpc_call implementation
 456  */
 457 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 458 {
 459         struct rpc_task *task;
 460         sigset_t        oldset;
 461         int             status;
 462
 463         /* If this client is slain all further I/O fails */
 464         if (clnt->cl_dead)
 465                 return -EIO;
 466
 467         BUG_ON(flags & RPC_TASK_ASYNC);
 468
 469         status = -ENOMEM;
 470         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 471         if (task == NULL)
 472                 goto out;
 473
 474         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 475         rpc_task_sigmask(task, &oldset);
 476
 477         rpc_call_setup(task, msg, 0);
 478
 479         /* Set up the call info struct and execute the task */
 480         status = task->tk_status;
 481         if (status == 0) {
 482                 atomic_inc(&task->tk_count);
 483                 status = rpc_execute(task);
 484                 if (status == 0)
 485                         status = task->tk_status;
 486         }
 487         rpc_restore_sigmask(&oldset);
 488         rpc_release_task(task);
 489 out:
 490         return status;
 491 }
 492
 493 /*
 494  * New rpc_call implementation
 495  */
 496 int
 497 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 498                const struct rpc_call_ops *tk_ops, void *data)
 499 {
 500         struct rpc_task *task;
 501         sigset_t        oldset;
 502         int             status;
 503
 504         /* If this client is slain all further I/O fails */
 505         status = -EIO;
 506         if (clnt->cl_dead)
 507                 goto out_release;
 508
 509         flags |= RPC_TASK_ASYNC;
 510
 511         /* Create/initialize a new RPC task */
 512         status = -ENOMEM;
 513         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 514                 goto out_release;
 515
 516         /* Mask signals on GSS_AUTH upcalls */
 517         rpc_task_sigmask(task, &oldset);
 518
 519         rpc_call_setup(task, msg, 0);
 520
 521         /* Set up the call info struct and execute the task */
 522         status = task->tk_status;
 523         if (status == 0)
 524                 rpc_execute(task);
 525         else
 526                 rpc_release_task(task);
 527
 528         rpc_restore_sigmask(&oldset);
 529         return status;
 530 out_release:
 531         if (tk_ops->rpc_release != NULL)
 532                 tk_ops->rpc_release(data);
 533         return status;
 534 }
 535
 536
 537 void
 538 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 539 {
 540         task->tk_msg   = *msg;
 541         task->tk_flags |= flags;
 542         /* Bind the user cred */
 543         if (task->tk_msg.rpc_cred != NULL)
 544                 rpcauth_holdcred(task);
 545         else
 546                 rpcauth_bindcred(task);
 547
 548         if (task->tk_status == 0)
 549                 task->tk_action = call_start;
 550         else
 551                 task->tk_action = rpc_exit_task;
 552 }
 553
 554 /**
 555  * rpc_peeraddr - extract remote peer address from clnt's xprt
 556  * @clnt: RPC client structure
 557  * @buf: target buffer
 558  * @size: length of target buffer
 559  *
 560  * Returns the number of bytes that are actually in the stored address.
 561  */
 562 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 563 {
 564         size_t bytes;
 565         struct rpc_xprt *xprt = clnt->cl_xprt;
 566
 567         bytes = sizeof(xprt->addr);
 568         if (bytes > bufsize)
 569                 bytes = bufsize;
 570         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 571         return xprt->addrlen;
 572 }
 573 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 574
 575 /**
 576  * rpc_peeraddr2str - return remote peer address in printable format
 577  * @clnt: RPC client structure
 578  * @format: address format
 579  *
 580  */
 581 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 582 {
 583         struct rpc_xprt *xprt = clnt->cl_xprt;
 584         return xprt->ops->print_addr(xprt, format);
 585 }
 586 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 587
 588 void
 589 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 590 {
 591         struct rpc_xprt *xprt = clnt->cl_xprt;
 592         if (xprt->ops->set_buffer_size)
 593                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 594 }
 595
 596 /*
 597  * Return size of largest payload RPC client can support, in bytes
 598  *
 599  * For stream transports, this is one RPC record fragment (see RFC
 600  * 1831), as we don't support multi-record requests yet.  For datagram
 601  * transports, this is the size of an IP packet minus the IP, UDP, and
 602  * RPC header sizes.
 603  */
 604 size_t rpc_max_payload(struct rpc_clnt *clnt)
 605 {
 606         return clnt->cl_xprt->max_payload;
 607 }
 608 EXPORT_SYMBOL_GPL(rpc_max_payload);
 609
 610 /**
 611  * rpc_force_rebind - force transport to check that remote port is unchanged
 612  * @clnt: client to rebind
 613  *
 614  */
 615 void rpc_force_rebind(struct rpc_clnt *clnt)
 616 {
 617         if (clnt->cl_autobind)
 618                 xprt_clear_bound(clnt->cl_xprt);
 619 }
 620 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 621
 622 /*
 623  * Restart an (async) RPC call. Usually called from within the
 624  * exit handler.
 625  */
 626 void
 627 rpc_restart_call(struct rpc_task *task)
 628 {
 629         if (RPC_ASSASSINATED(task))
 630                 return;
 631
 632         task->tk_action = call_start;
 633 }
 634
 635 /*
 636  * 0.  Initial state
 637  *
 638  *     Other FSM states can be visited zero or more times, but
 639  *     this state is visited exactly once for each RPC.
 640  */
 641 static void
 642 call_start(struct rpc_task *task)
 643 {
 644         struct rpc_clnt *clnt = task->tk_client;
 645
 646         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 647                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 648                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 649
 650         /* Increment call count */
 651         task->tk_msg.rpc_proc->p_count++;
 652         clnt->cl_stats->rpccnt++;
 653         task->tk_action = call_reserve;
 654 }
 655
 656 /*
 657  * 1.   Reserve an RPC call slot
 658  */
 659 static void
 660 call_reserve(struct rpc_task *task)
 661 {
 662         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 663
 664         if (!rpcauth_uptodatecred(task)) {
 665                 task->tk_action = call_refresh;
 666                 return;
 667         }
 668
 669         task->tk_status  = 0;
 670         task->tk_action  = call_reserveresult;
 671         xprt_reserve(task);
 672 }
 673
 674 /*
 675  * 1b.  Grok the result of xprt_reserve()
 676  */
 677 static void
 678 call_reserveresult(struct rpc_task *task)
 679 {
 680         int status = task->tk_status;
 681
 682         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 683                                 task->tk_pid, task->tk_status);
 684
 685         /*
 686          * After a call to xprt_reserve(), we must have either
 687          * a request slot or else an error status.
 688          */
 689         task->tk_status = 0;
 690         if (status >= 0) {
 691                 if (task->tk_rqstp) {
 692                         task->tk_action = call_allocate;
 693                         return;
 694                 }
 695
 696                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 697                                 __FUNCTION__, status);
 698                 rpc_exit(task, -EIO);
 699                 return;
 700         }
 701
 702         /*
 703          * Even though there was an error, we may have acquired
 704          * a request slot somehow.  Make sure not to leak it.
 705          */
 706         if (task->tk_rqstp) {
 707                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 708                                 __FUNCTION__, status);
 709                 xprt_release(task);
 710         }
 711
 712         switch (status) {
 713         case -EAGAIN:   /* woken up; retry */
 714                 task->tk_action = call_reserve;
 715                 return;
 716         case -EIO:      /* probably a shutdown */
 717                 break;
 718         default:
 719                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 720                                 __FUNCTION__, status);
 721                 break;
 722         }
 723         rpc_exit(task, status);
 724 }
 725
 726 /*
 727  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 728  *      (Note: buffer memory is freed in xprt_release).
 729  */
 730 static void
 731 call_allocate(struct rpc_task *task)
 732 {
 733         struct rpc_rqst *req = task->tk_rqstp;
 734         struct rpc_xprt *xprt = task->tk_xprt;
 735         unsigned int    bufsiz;
 736
 737         dprintk("RPC: %4d call_allocate (status %d)\n",
 738                                 task->tk_pid, task->tk_status);
 739         task->tk_action = call_bind;
 740         if (req->rq_buffer)
 741                 return;
 742
 743         /* FIXME: compute buffer requirements more exactly using
 744          * auth->au_wslack */
 745         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 746
 747         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 748                 return;
 749         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 750
 751         if (RPC_IS_ASYNC(task) || !signalled()) {
 752                 xprt_release(task);
 753                 task->tk_action = call_reserve;
 754                 rpc_delay(task, HZ>>4);
 755                 return;
 756         }
 757
 758         rpc_exit(task, -ERESTARTSYS);
 759 }
 760
 761 static inline int
 762 rpc_task_need_encode(struct rpc_task *task)
 763 {
 764         return task->tk_rqstp->rq_snd_buf.len == 0;
 765 }
 766
 767 static inline void
 768 rpc_task_force_reencode(struct rpc_task *task)
 769 {
 770         task->tk_rqstp->rq_snd_buf.len = 0;
 771 }
 772
 773 /*
 774  * 3.   Encode arguments of an RPC call
 775  */
 776 static void
 777 call_encode(struct rpc_task *task)
 778 {
 779         struct rpc_rqst *req = task->tk_rqstp;
 780         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 781         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 782         unsigned int    bufsiz;
 783         kxdrproc_t      encode;
 784         __be32          *p;
 785
 786         dprintk("RPC: %4d call_encode (status %d)\n",
 787                                 task->tk_pid, task->tk_status);
 788
 789         /* Default buffer setup */
 790         bufsiz = req->rq_bufsize >> 1;
 791         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 792         sndbuf->head[0].iov_len  = bufsiz;
 793         sndbuf->tail[0].iov_len  = 0;
 794         sndbuf->page_len         = 0;
 795         sndbuf->len              = 0;
 796         sndbuf->buflen           = bufsiz;
 797         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 798         rcvbuf->head[0].iov_len  = bufsiz;
 799         rcvbuf->tail[0].iov_len  = 0;
 800         rcvbuf->page_len         = 0;
 801         rcvbuf->len              = 0;
 802         rcvbuf->buflen           = bufsiz;
 803
 804         /* Encode header and provided arguments */
 805         encode = task->tk_msg.rpc_proc->p_encode;
 806         if (!(p = call_header(task))) {
 807                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 808                 rpc_exit(task, -EIO);
 809                 return;
 810         }
 811         if (encode == NULL)
 812                 return;
 813
 814         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 815                         task->tk_msg.rpc_argp);
 816         if (task->tk_status == -ENOMEM) {
 817                 /* XXX: Is this sane? */
 818                 rpc_delay(task, 3*HZ);
 819                 task->tk_status = -EAGAIN;
 820         }
 821 }
 822
 823 /*
 824  * 4.   Get the server port number if not yet set
 825  */
 826 static void
 827 call_bind(struct rpc_task *task)
 828 {
 829         struct rpc_xprt *xprt = task->tk_xprt;
 830
 831         dprintk("RPC: %4d call_bind (status %d)\n",
 832                                 task->tk_pid, task->tk_status);
 833
 834         task->tk_action = call_connect;
 835         if (!xprt_bound(xprt)) {
 836                 task->tk_action = call_bind_status;
 837                 task->tk_timeout = xprt->bind_timeout;
 838                 xprt->ops->rpcbind(task);
 839         }
 840 }
 841
 842 /*
 843  * 4a.  Sort out bind result
 844  */
 845 static void
 846 call_bind_status(struct rpc_task *task)
 847 {
 848         int status = -EACCES;
 849
 850         if (task->tk_status >= 0) {
 851                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 852                                         task->tk_pid, task->tk_status);
 853                 task->tk_status = 0;
 854                 task->tk_action = call_connect;
 855                 return;
 856         }
 857
 858         switch (task->tk_status) {
 859         case -EACCES:
 860                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
 861                                 task->tk_pid);
 862                 rpc_delay(task, 3*HZ);
 863                 goto retry_timeout;
 864         case -ETIMEDOUT:
 865                 dprintk("RPC: %4d rpcbind request timed out\n",
 866                                 task->tk_pid);
 867                 goto retry_timeout;
 868         case -EPFNOSUPPORT:
 869                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 870                                 task->tk_pid);
 871                 break;
 872         case -EPROTONOSUPPORT:
 873                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 874                                 task->tk_pid);
 875                 break;
 876         default:
 877                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 878                                 task->tk_pid, -task->tk_status);
 879                 status = -EIO;
 880         }
 881
 882         rpc_exit(task, status);
 883         return;
 884
 885 retry_timeout:
 886         task->tk_action = call_timeout;
 887 }
 888
 889 /*
 890  * 4b.  Connect to the RPC server
 891  */
 892 static void
 893 call_connect(struct rpc_task *task)
 894 {
 895         struct rpc_xprt *xprt = task->tk_xprt;
 896
 897         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 898                         task->tk_pid, xprt,
 899                         (xprt_connected(xprt) ? "is" : "is not"));
 900
 901         task->tk_action = call_transmit;
 902         if (!xprt_connected(xprt)) {
 903                 task->tk_action = call_connect_status;
 904                 if (task->tk_status < 0)
 905                         return;
 906                 xprt_connect(task);
 907         }
 908 }
 909
 910 /*
 911  * 4c.  Sort out connect result
 912  */
 913 static void
 914 call_connect_status(struct rpc_task *task)
 915 {
 916         struct rpc_clnt *clnt = task->tk_client;
 917         int status = task->tk_status;
 918
 919         dprintk("RPC: %5u call_connect_status (status %d)\n",
 920                                 task->tk_pid, task->tk_status);
 921
 922         task->tk_status = 0;
 923         if (status >= 0) {
 924                 clnt->cl_stats->netreconn++;
 925                 task->tk_action = call_transmit;
 926                 return;
 927         }
 928
 929         /* Something failed: remote service port may have changed */
 930         rpc_force_rebind(clnt);
 931
 932         switch (status) {
 933         case -ENOTCONN:
 934         case -EAGAIN:
 935                 task->tk_action = call_bind;
 936                 if (!RPC_IS_SOFT(task))
 937                         return;
 938                 /* if soft mounted, test if we've timed out */
 939         case -ETIMEDOUT:
 940                 task->tk_action = call_timeout;
 941                 return;
 942         }
 943         rpc_exit(task, -EIO);
 944 }
 945
 946 /*
 947  * 5.   Transmit the RPC request, and wait for reply
 948  */
 949 static void
 950 call_transmit(struct rpc_task *task)
 951 {
 952         dprintk("RPC: %4d call_transmit (status %d)\n",
 953                                 task->tk_pid, task->tk_status);
 954
 955         task->tk_action = call_status;
 956         if (task->tk_status < 0)
 957                 return;
 958         task->tk_status = xprt_prepare_transmit(task);
 959         if (task->tk_status != 0)
 960                 return;
 961         task->tk_action = call_transmit_status;
 962         /* Encode here so that rpcsec_gss can use correct sequence number. */
 963         if (rpc_task_need_encode(task)) {
 964                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 965                 call_encode(task);
 966                 /* Did the encode result in an error condition? */
 967                 if (task->tk_status != 0)
 968                         return;
 969         }
 970         xprt_transmit(task);
 971         if (task->tk_status < 0)
 972                 return;
 973         /*
 974          * On success, ensure that we call xprt_end_transmit() before sleeping
 975          * in order to allow access to the socket to other RPC requests.
 976          */
 977         call_transmit_status(task);
 978         if (task->tk_msg.rpc_proc->p_decode != NULL)
 979                 return;
 980         task->tk_action = rpc_exit_task;
 981         rpc_wake_up_task(task);
 982 }
 983
 984 /*
 985  * 5a.  Handle cleanup after a transmission
 986  */
 987 static void
 988 call_transmit_status(struct rpc_task *task)
 989 {
 990         task->tk_action = call_status;
 991         /*
 992          * Special case: if we've been waiting on the socket's write_space()
 993          * callback, then don't call xprt_end_transmit().
 994          */
 995         if (task->tk_status == -EAGAIN)
 996                 return;
 997         xprt_end_transmit(task);
 998         rpc_task_force_reencode(task);
 999 }
1000
1001 /*
1002  * 6.   Sort out the RPC call status
1003  */
1004 static void
1005 call_status(struct rpc_task *task)
1006 {
1007         struct rpc_clnt *clnt = task->tk_client;
1008         struct rpc_rqst *req = task->tk_rqstp;
1009         int             status;
1010
1011         if (req->rq_received > 0 && !req->rq_bytes_sent)
1012                 task->tk_status = req->rq_received;
1013
1014         dprintk("RPC: %4d call_status (status %d)\n",
1015                                 task->tk_pid, task->tk_status);
1016
1017         status = task->tk_status;
1018         if (status >= 0) {
1019                 task->tk_action = call_decode;
1020                 return;
1021         }
1022
1023         task->tk_status = 0;
1024         switch(status) {
1025         case -EHOSTDOWN:
1026         case -EHOSTUNREACH:
1027         case -ENETUNREACH:
1028                 /*
1029                  * Delay any retries for 3 seconds, then handle as if it
1030                  * were a timeout.
1031                  */
1032                 rpc_delay(task, 3*HZ);
1033         case -ETIMEDOUT:
1034                 task->tk_action = call_timeout;
1035                 break;
1036         case -ECONNREFUSED:
1037         case -ENOTCONN:
1038                 rpc_force_rebind(clnt);
1039                 task->tk_action = call_bind;
1040                 break;
1041         case -EAGAIN:
1042                 task->tk_action = call_transmit;
1043                 break;
1044         case -EIO:
1045                 /* shutdown or soft timeout */
1046                 rpc_exit(task, status);
1047                 break;
1048         default:
1049                 printk("%s: RPC call returned error %d\n",
1050                                clnt->cl_protname, -status);
1051                 rpc_exit(task, status);
1052         }
1053 }
1054
1055 /*
1056  * 6a.  Handle RPC timeout
1057  *      We do not release the request slot, so we keep using the
1058  *      same XID for all retransmits.
1059  */
1060 static void
1061 call_timeout(struct rpc_task *task)
1062 {
1063         struct rpc_clnt *clnt = task->tk_client;
1064
1065         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1066                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1067                 goto retry;
1068         }
1069
1070         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1071         task->tk_timeouts++;
1072
1073         if (RPC_IS_SOFT(task)) {
1074                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1075                                 clnt->cl_protname, clnt->cl_server);
1076                 rpc_exit(task, -EIO);
1077                 return;
1078         }
1079
1080         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1081                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1082                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1083                         clnt->cl_protname, clnt->cl_server);
1084         }
1085         rpc_force_rebind(clnt);
1086
1087 retry:
1088         clnt->cl_stats->rpcretrans++;
1089         task->tk_action = call_bind;
1090         task->tk_status = 0;
1091 }
1092
1093 /*
1094  * 7.   Decode the RPC reply
1095  */
1096 static void
1097 call_decode(struct rpc_task *task)
1098 {
1099         struct rpc_clnt *clnt = task->tk_client;
1100         struct rpc_rqst *req = task->tk_rqstp;
1101         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1102         __be32          *p;
1103
1104         dprintk("RPC: %4d call_decode (status %d)\n",
1105                                 task->tk_pid, task->tk_status);
1106
1107         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1108                 printk(KERN_NOTICE "%s: server %s OK\n",
1109                         clnt->cl_protname, clnt->cl_server);
1110                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1111         }
1112
1113         if (task->tk_status < 12) {
1114                 if (!RPC_IS_SOFT(task)) {
1115                         task->tk_action = call_bind;
1116                         clnt->cl_stats->rpcretrans++;
1117                         goto out_retry;
1118                 }
1119                 dprintk("%s: too small RPC reply size (%d bytes)\n",
1120                         clnt->cl_protname, task->tk_status);
1121                 task->tk_action = call_timeout;
1122                 goto out_retry;
1123         }
1124
1125         /*
1126          * Ensure that we see all writes made by xprt_complete_rqst()
1127          * before it changed req->rq_received.
1128          */
1129         smp_rmb();
1130         req->rq_rcv_buf.len = req->rq_private_buf.len;
1131
1132         /* Check that the softirq receive buffer is valid */
1133         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1134                                 sizeof(req->rq_rcv_buf)) != 0);
1135
1136         /* Verify the RPC header */
1137         p = call_verify(task);
1138         if (IS_ERR(p)) {
1139                 if (p == ERR_PTR(-EAGAIN))
1140                         goto out_retry;
1141                 return;
1142         }
1143
1144         task->tk_action = rpc_exit_task;
1145
1146         if (decode)
1147                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1148                                                       task->tk_msg.rpc_resp);
1149         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1150                                         task->tk_status);
1151         return;
1152 out_retry:
1153         req->rq_received = req->rq_private_buf.len = 0;
1154         task->tk_status = 0;
1155 }
1156
1157 /*
1158  * 8.   Refresh the credentials if rejected by the server
1159  */
1160 static void
1161 call_refresh(struct rpc_task *task)
1162 {
1163         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1164
1165         xprt_release(task);     /* Must do to obtain new XID */
1166         task->tk_action = call_refreshresult;
1167         task->tk_status = 0;
1168         task->tk_client->cl_stats->rpcauthrefresh++;
1169         rpcauth_refreshcred(task);
1170 }
1171
1172 /*
1173  * 8a.  Process the results of a credential refresh
1174  */
1175 static void
1176 call_refreshresult(struct rpc_task *task)
1177 {
1178         int status = task->tk_status;
1179         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1180                                 task->tk_pid, task->tk_status);
1181
1182         task->tk_status = 0;
1183         task->tk_action = call_reserve;
1184         if (status >= 0 && rpcauth_uptodatecred(task))
1185                 return;
1186         if (status == -EACCES) {
1187                 rpc_exit(task, -EACCES);
1188                 return;
1189         }
1190         task->tk_action = call_refresh;
1191         if (status != -ETIMEDOUT)
1192                 rpc_delay(task, 3*HZ);
1193         return;
1194 }
1195
1196 /*
1197  * Call header serialization
1198  */
1199 static __be32 *
1200 call_header(struct rpc_task *task)
1201 {
1202         struct rpc_clnt *clnt = task->tk_client;
1203         struct rpc_rqst *req = task->tk_rqstp;
1204         __be32          *p = req->rq_svec[0].iov_base;
1205
1206         /* FIXME: check buffer size? */
1207
1208         p = xprt_skip_transport_header(task->tk_xprt, p);
1209         *p++ = req->rq_xid;             /* XID */
1210         *p++ = htonl(RPC_CALL);         /* CALL */
1211         *p++ = htonl(RPC_VERSION);      /* RPC version */
1212         *p++ = htonl(clnt->cl_prog);    /* program number */
1213         *p++ = htonl(clnt->cl_vers);    /* program version */
1214         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1215         p = rpcauth_marshcred(task, p);
1216         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1217         return p;
1218 }
1219
1220 /*
1221  * Reply header verification
1222  */
1223 static __be32 *
1224 call_verify(struct rpc_task *task)
1225 {
1226         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1227         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1228         __be32  *p = iov->iov_base;
1229         u32 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 - (__be32 *)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, __be32 *data, void *obj)
1362 {
1363         return 0;
1364 }
1365
1366 static int rpcproc_decode_null(void *rqstp, __be32 *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 }