err.no Git - linux-2.6/blob - 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 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 /*
 101  * Create an RPC client
 102  * FIXME: This should also take a flags argument (as in task->tk_flags).
 103  * It's called (among others) from pmap_create_client, which may in
 104  * turn be called by an async task. In this case, rpciod should not be
 105  * made to sleep too long.
 106  */
 107 struct rpc_clnt *
 108 rpc_new_client(struct rpc_xprt *xprt, char *servname,
 109                   struct rpc_program *program, u32 vers,
 110                   rpc_authflavor_t flavor)
 111 {
 112         struct rpc_version      *version;
 113         struct rpc_clnt         *clnt = NULL;
 114         struct rpc_auth         *auth;
 115         int err;
 116         int len;
 117
 118         dprintk("RPC: creating %s client for %s (xprt %p)\n",
 119                 program->name, servname, xprt);
 120
 121         err = -EINVAL;
 122         if (!xprt)
 123                 goto out_no_xprt;
 124         if (vers >= program->nrvers || !(version = program->version[vers]))
 125                 goto out_err;
 126
 127         err = -ENOMEM;
 128         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 129         if (!clnt)
 130                 goto out_err;
 131         atomic_set(&clnt->cl_users, 0);
 132         atomic_set(&clnt->cl_count, 1);
 133         clnt->cl_parent = clnt;
 134
 135         clnt->cl_server = clnt->cl_inline_name;
 136         len = strlen(servname) + 1;
 137         if (len > sizeof(clnt->cl_inline_name)) {
 138                 char *buf = kmalloc(len, GFP_KERNEL);
 139                 if (buf != 0)
 140                         clnt->cl_server = buf;
 141                 else
 142                         len = sizeof(clnt->cl_inline_name);
 143         }
 144         strlcpy(clnt->cl_server, servname, len);
 145
 146         clnt->cl_xprt     = xprt;
 147         clnt->cl_procinfo = version->procs;
 148         clnt->cl_maxproc  = version->nrprocs;
 149         clnt->cl_protname = program->name;
 150         clnt->cl_pmap     = &clnt->cl_pmap_default;
 151         clnt->cl_prog     = program->number;
 152         clnt->cl_vers     = version->number;
 153         clnt->cl_prot     = xprt->prot;
 154         clnt->cl_stats    = program->stats;
 155         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 156         rpc_init_wait_queue(&clnt->cl_pmap_default.pm_bindwait, "bindwait");
 157
 158         if (!xprt_bound(clnt->cl_xprt))
 159                 clnt->cl_autobind = 1;
 160
 161         clnt->cl_rtt = &clnt->cl_rtt_default;
 162         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 163
 164         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 165         if (err < 0)
 166                 goto out_no_path;
 167
 168         auth = rpcauth_create(flavor, clnt);
 169         if (IS_ERR(auth)) {
 170                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 171                                 flavor);
 172                 err = PTR_ERR(auth);
 173                 goto out_no_auth;
 174         }
 175
 176         /* save the nodename */
 177         clnt->cl_nodelen = strlen(system_utsname.nodename);
 178         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 179                 clnt->cl_nodelen = UNX_MAXNODENAME;
 180         memcpy(clnt->cl_nodename, system_utsname.nodename, clnt->cl_nodelen);
 181         return clnt;
 182
 183 out_no_auth:
 184         if (!IS_ERR(clnt->cl_dentry)) {
 185                 rpc_rmdir(clnt->cl_dentry);
 186                 rpc_put_mount();
 187         }
 188 out_no_path:
 189         if (clnt->cl_server != clnt->cl_inline_name)
 190                 kfree(clnt->cl_server);
 191         kfree(clnt);
 192 out_err:
 193         xprt_destroy(xprt);
 194 out_no_xprt:
 195         return ERR_PTR(err);
 196 }
 197
 198 /**
 199  * Create an RPC client
 200  * @xprt - pointer to xprt struct
 201  * @servname - name of server
 202  * @info - rpc_program
 203  * @version - rpc_program version
 204  * @authflavor - rpc_auth flavour to use
 205  *
 206  * Creates an RPC client structure, then pings the server in order to
 207  * determine if it is up, and if it supports this program and version.
 208  *
 209  * This function should never be called by asynchronous tasks such as
 210  * the portmapper.
 211  */
 212 struct rpc_clnt *rpc_create_client(struct rpc_xprt *xprt, char *servname,
 213                 struct rpc_program *info, u32 version, rpc_authflavor_t authflavor)
 214 {
 215         struct rpc_clnt *clnt;
 216         int err;
 217
 218         clnt = rpc_new_client(xprt, servname, info, version, authflavor);
 219         if (IS_ERR(clnt))
 220                 return clnt;
 221         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 222         if (err == 0)
 223                 return clnt;
 224         rpc_shutdown_client(clnt);
 225         return ERR_PTR(err);
 226 }
 227
 228 /*
 229  * This function clones the RPC client structure. It allows us to share the
 230  * same transport while varying parameters such as the authentication
 231  * flavour.
 232  */
 233 struct rpc_clnt *
 234 rpc_clone_client(struct rpc_clnt *clnt)
 235 {
 236         struct rpc_clnt *new;
 237
 238         new = kmalloc(sizeof(*new), GFP_KERNEL);
 239         if (!new)
 240                 goto out_no_clnt;
 241         memcpy(new, clnt, sizeof(*new));
 242         atomic_set(&new->cl_count, 1);
 243         atomic_set(&new->cl_users, 0);
 244         new->cl_parent = clnt;
 245         atomic_inc(&clnt->cl_count);
 246         /* Duplicate portmapper */
 247         rpc_init_wait_queue(&new->cl_pmap_default.pm_bindwait, "bindwait");
 248         /* Turn off autobind on clones */
 249         new->cl_autobind = 0;
 250         new->cl_oneshot = 0;
 251         new->cl_dead = 0;
 252         if (!IS_ERR(new->cl_dentry))
 253                 dget(new->cl_dentry);
 254         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 255         if (new->cl_auth)
 256                 atomic_inc(&new->cl_auth->au_count);
 257         new->cl_pmap            = &new->cl_pmap_default;
 258         new->cl_metrics         = rpc_alloc_iostats(clnt);
 259         return new;
 260 out_no_clnt:
 261         printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
 262         return ERR_PTR(-ENOMEM);
 263 }
 264
 265 /*
 266  * Properly shut down an RPC client, terminating all outstanding
 267  * requests. Note that we must be certain that cl_oneshot and
 268  * cl_dead are cleared, or else the client would be destroyed
 269  * when the last task releases it.
 270  */
 271 int
 272 rpc_shutdown_client(struct rpc_clnt *clnt)
 273 {
 274         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
 275                         clnt->cl_protname, clnt->cl_server,
 276                         atomic_read(&clnt->cl_users));
 277
 278         while (atomic_read(&clnt->cl_users) > 0) {
 279                 /* Don't let rpc_release_client destroy us */
 280                 clnt->cl_oneshot = 0;
 281                 clnt->cl_dead = 0;
 282                 rpc_killall_tasks(clnt);
 283                 wait_event_timeout(destroy_wait,
 284                         !atomic_read(&clnt->cl_users), 1*HZ);
 285         }
 286
 287         if (atomic_read(&clnt->cl_users) < 0) {
 288                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 289                                 clnt, atomic_read(&clnt->cl_users));
 290 #ifdef RPC_DEBUG
 291                 rpc_show_tasks();
 292 #endif
 293                 BUG();
 294         }
 295
 296         return rpc_destroy_client(clnt);
 297 }
 298
 299 /*
 300  * Delete an RPC client
 301  */
 302 int
 303 rpc_destroy_client(struct rpc_clnt *clnt)
 304 {
 305         if (!atomic_dec_and_test(&clnt->cl_count))
 306                 return 1;
 307         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 308
 309         dprintk("RPC: destroying %s client for %s\n",
 310                         clnt->cl_protname, clnt->cl_server);
 311         if (clnt->cl_auth) {
 312                 rpcauth_destroy(clnt->cl_auth);
 313                 clnt->cl_auth = NULL;
 314         }
 315         if (clnt->cl_parent != clnt) {
 316                 if (!IS_ERR(clnt->cl_dentry))
 317                         dput(clnt->cl_dentry);
 318                 rpc_destroy_client(clnt->cl_parent);
 319                 goto out_free;
 320         }
 321         if (!IS_ERR(clnt->cl_dentry)) {
 322                 rpc_rmdir(clnt->cl_dentry);
 323                 rpc_put_mount();
 324         }
 325         if (clnt->cl_xprt) {
 326                 xprt_destroy(clnt->cl_xprt);
 327                 clnt->cl_xprt = NULL;
 328         }
 329         if (clnt->cl_server != clnt->cl_inline_name)
 330                 kfree(clnt->cl_server);
 331 out_free:
 332         rpc_free_iostats(clnt->cl_metrics);
 333         clnt->cl_metrics = NULL;
 334         kfree(clnt);
 335         return 0;
 336 }
 337
 338 /*
 339  * Release an RPC client
 340  */
 341 void
 342 rpc_release_client(struct rpc_clnt *clnt)
 343 {
 344         dprintk("RPC:      rpc_release_client(%p, %d)\n",
 345                                 clnt, atomic_read(&clnt->cl_users));
 346
 347         if (!atomic_dec_and_test(&clnt->cl_users))
 348                 return;
 349         wake_up(&destroy_wait);
 350         if (clnt->cl_oneshot || clnt->cl_dead)
 351                 rpc_destroy_client(clnt);
 352 }
 353
 354 /**
 355  * rpc_bind_new_program - bind a new RPC program to an existing client
 356  * @old - old rpc_client
 357  * @program - rpc program to set
 358  * @vers - rpc program version
 359  *
 360  * Clones the rpc client and sets up a new RPC program. This is mainly
 361  * of use for enabling different RPC programs to share the same transport.
 362  * The Sun NFSv2/v3 ACL protocol can do this.
 363  */
 364 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 365                                       struct rpc_program *program,
 366                                       int vers)
 367 {
 368         struct rpc_clnt *clnt;
 369         struct rpc_version *version;
 370         int err;
 371
 372         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 373         version = program->version[vers];
 374         clnt = rpc_clone_client(old);
 375         if (IS_ERR(clnt))
 376                 goto out;
 377         clnt->cl_procinfo = version->procs;
 378         clnt->cl_maxproc  = version->nrprocs;
 379         clnt->cl_protname = program->name;
 380         clnt->cl_prog     = program->number;
 381         clnt->cl_vers     = version->number;
 382         clnt->cl_stats    = program->stats;
 383         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 384         if (err != 0) {
 385                 rpc_shutdown_client(clnt);
 386                 clnt = ERR_PTR(err);
 387         }
 388 out:
 389         return clnt;
 390 }
 391
 392 /*
 393  * Default callback for async RPC calls
 394  */
 395 static void
 396 rpc_default_callback(struct rpc_task *task, void *data)
 397 {
 398 }
 399
 400 static const struct rpc_call_ops rpc_default_ops = {
 401         .rpc_call_done = rpc_default_callback,
 402 };
 403
 404 /*
 405  *      Export the signal mask handling for synchronous code that
 406  *      sleeps on RPC calls
 407  */
 408 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 409
 410 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 411 {
 412         unsigned long   sigallow = sigmask(SIGKILL);
 413         sigset_t sigmask;
 414
 415         /* Block all signals except those listed in sigallow */
 416         if (intr)
 417                 sigallow |= RPC_INTR_SIGNALS;
 418         siginitsetinv(&sigmask, sigallow);
 419         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 420 }
 421
 422 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 423 {
 424         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 425 }
 426
 427 static inline void rpc_restore_sigmask(sigset_t *oldset)
 428 {
 429         sigprocmask(SIG_SETMASK, oldset, NULL);
 430 }
 431
 432 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 433 {
 434         rpc_save_sigmask(oldset, clnt->cl_intr);
 435 }
 436
 437 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 438 {
 439         rpc_restore_sigmask(oldset);
 440 }
 441
 442 /*
 443  * New rpc_call implementation
 444  */
 445 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 446 {
 447         struct rpc_task *task;
 448         sigset_t        oldset;
 449         int             status;
 450
 451         /* If this client is slain all further I/O fails */
 452         if (clnt->cl_dead)
 453                 return -EIO;
 454
 455         BUG_ON(flags & RPC_TASK_ASYNC);
 456
 457         status = -ENOMEM;
 458         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 459         if (task == NULL)
 460                 goto out;
 461
 462         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 463         rpc_task_sigmask(task, &oldset);
 464
 465         rpc_call_setup(task, msg, 0);
 466
 467         /* Set up the call info struct and execute the task */
 468         status = task->tk_status;
 469         if (status == 0) {
 470                 atomic_inc(&task->tk_count);
 471                 status = rpc_execute(task);
 472                 if (status == 0)
 473                         status = task->tk_status;
 474         }
 475         rpc_restore_sigmask(&oldset);
 476         rpc_release_task(task);
 477 out:
 478         return status;
 479 }
 480
 481 /*
 482  * New rpc_call implementation
 483  */
 484 int
 485 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 486                const struct rpc_call_ops *tk_ops, void *data)
 487 {
 488         struct rpc_task *task;
 489         sigset_t        oldset;
 490         int             status;
 491
 492         /* If this client is slain all further I/O fails */
 493         status = -EIO;
 494         if (clnt->cl_dead)
 495                 goto out_release;
 496
 497         flags |= RPC_TASK_ASYNC;
 498
 499         /* Create/initialize a new RPC task */
 500         status = -ENOMEM;
 501         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 502                 goto out_release;
 503
 504         /* Mask signals on GSS_AUTH upcalls */
 505         rpc_task_sigmask(task, &oldset);
 506
 507         rpc_call_setup(task, msg, 0);
 508
 509         /* Set up the call info struct and execute the task */
 510         status = task->tk_status;
 511         if (status == 0)
 512                 rpc_execute(task);
 513         else
 514                 rpc_release_task(task);
 515
 516         rpc_restore_sigmask(&oldset);
 517         return status;
 518 out_release:
 519         if (tk_ops->rpc_release != NULL)
 520                 tk_ops->rpc_release(data);
 521         return status;
 522 }
 523
 524
 525 void
 526 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 527 {
 528         task->tk_msg   = *msg;
 529         task->tk_flags |= flags;
 530         /* Bind the user cred */
 531         if (task->tk_msg.rpc_cred != NULL)
 532                 rpcauth_holdcred(task);
 533         else
 534                 rpcauth_bindcred(task);
 535
 536         if (task->tk_status == 0)
 537                 task->tk_action = call_start;
 538         else
 539                 task->tk_action = rpc_exit_task;
 540 }
 541
 542 void
 543 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 544 {
 545         struct rpc_xprt *xprt = clnt->cl_xprt;
 546         if (xprt->ops->set_buffer_size)
 547                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 548 }
 549
 550 /*
 551  * Return size of largest payload RPC client can support, in bytes
 552  *
 553  * For stream transports, this is one RPC record fragment (see RFC
 554  * 1831), as we don't support multi-record requests yet.  For datagram
 555  * transports, this is the size of an IP packet minus the IP, UDP, and
 556  * RPC header sizes.
 557  */
 558 size_t rpc_max_payload(struct rpc_clnt *clnt)
 559 {
 560         return clnt->cl_xprt->max_payload;
 561 }
 562 EXPORT_SYMBOL(rpc_max_payload);
 563
 564 /**
 565  * rpc_force_rebind - force transport to check that remote port is unchanged
 566  * @clnt: client to rebind
 567  *
 568  */
 569 void rpc_force_rebind(struct rpc_clnt *clnt)
 570 {
 571         if (clnt->cl_autobind)
 572                 xprt_clear_bound(clnt->cl_xprt);
 573 }
 574 EXPORT_SYMBOL(rpc_force_rebind);
 575
 576 /*
 577  * Restart an (async) RPC call. Usually called from within the
 578  * exit handler.
 579  */
 580 void
 581 rpc_restart_call(struct rpc_task *task)
 582 {
 583         if (RPC_ASSASSINATED(task))
 584                 return;
 585
 586         task->tk_action = call_start;
 587 }
 588
 589 /*
 590  * 0.  Initial state
 591  *
 592  *     Other FSM states can be visited zero or more times, but
 593  *     this state is visited exactly once for each RPC.
 594  */
 595 static void
 596 call_start(struct rpc_task *task)
 597 {
 598         struct rpc_clnt *clnt = task->tk_client;
 599
 600         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 601                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 602                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 603
 604         /* Increment call count */
 605         task->tk_msg.rpc_proc->p_count++;
 606         clnt->cl_stats->rpccnt++;
 607         task->tk_action = call_reserve;
 608 }
 609
 610 /*
 611  * 1.   Reserve an RPC call slot
 612  */
 613 static void
 614 call_reserve(struct rpc_task *task)
 615 {
 616         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 617
 618         if (!rpcauth_uptodatecred(task)) {
 619                 task->tk_action = call_refresh;
 620                 return;
 621         }
 622
 623         task->tk_status  = 0;
 624         task->tk_action  = call_reserveresult;
 625         xprt_reserve(task);
 626 }
 627
 628 /*
 629  * 1b.  Grok the result of xprt_reserve()
 630  */
 631 static void
 632 call_reserveresult(struct rpc_task *task)
 633 {
 634         int status = task->tk_status;
 635
 636         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 637                                 task->tk_pid, task->tk_status);
 638
 639         /*
 640          * After a call to xprt_reserve(), we must have either
 641          * a request slot or else an error status.
 642          */
 643         task->tk_status = 0;
 644         if (status >= 0) {
 645                 if (task->tk_rqstp) {
 646                         task->tk_action = call_allocate;
 647                         return;
 648                 }
 649
 650                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 651                                 __FUNCTION__, status);
 652                 rpc_exit(task, -EIO);
 653                 return;
 654         }
 655
 656         /*
 657          * Even though there was an error, we may have acquired
 658          * a request slot somehow.  Make sure not to leak it.
 659          */
 660         if (task->tk_rqstp) {
 661                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 662                                 __FUNCTION__, status);
 663                 xprt_release(task);
 664         }
 665
 666         switch (status) {
 667         case -EAGAIN:   /* woken up; retry */
 668                 task->tk_action = call_reserve;
 669                 return;
 670         case -EIO:      /* probably a shutdown */
 671                 break;
 672         default:
 673                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 674                                 __FUNCTION__, status);
 675                 break;
 676         }
 677         rpc_exit(task, status);
 678 }
 679
 680 /*
 681  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 682  *      (Note: buffer memory is freed in xprt_release).
 683  */
 684 static void
 685 call_allocate(struct rpc_task *task)
 686 {
 687         struct rpc_rqst *req = task->tk_rqstp;
 688         struct rpc_xprt *xprt = task->tk_xprt;
 689         unsigned int    bufsiz;
 690
 691         dprintk("RPC: %4d call_allocate (status %d)\n",
 692                                 task->tk_pid, task->tk_status);
 693         task->tk_action = call_bind;
 694         if (req->rq_buffer)
 695                 return;
 696
 697         /* FIXME: compute buffer requirements more exactly using
 698          * auth->au_wslack */
 699         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 700
 701         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 702                 return;
 703         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 704
 705         if (RPC_IS_ASYNC(task) || !signalled()) {
 706                 xprt_release(task);
 707                 task->tk_action = call_reserve;
 708                 rpc_delay(task, HZ>>4);
 709                 return;
 710         }
 711
 712         rpc_exit(task, -ERESTARTSYS);
 713 }
 714
 715 static inline int
 716 rpc_task_need_encode(struct rpc_task *task)
 717 {
 718         return task->tk_rqstp->rq_snd_buf.len == 0;
 719 }
 720
 721 static inline void
 722 rpc_task_force_reencode(struct rpc_task *task)
 723 {
 724         task->tk_rqstp->rq_snd_buf.len = 0;
 725 }
 726
 727 /*
 728  * 3.   Encode arguments of an RPC call
 729  */
 730 static void
 731 call_encode(struct rpc_task *task)
 732 {
 733         struct rpc_rqst *req = task->tk_rqstp;
 734         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 735         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 736         unsigned int    bufsiz;
 737         kxdrproc_t      encode;
 738         u32             *p;
 739
 740         dprintk("RPC: %4d call_encode (status %d)\n",
 741                                 task->tk_pid, task->tk_status);
 742
 743         /* Default buffer setup */
 744         bufsiz = req->rq_bufsize >> 1;
 745         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 746         sndbuf->head[0].iov_len  = bufsiz;
 747         sndbuf->tail[0].iov_len  = 0;
 748         sndbuf->page_len         = 0;
 749         sndbuf->len              = 0;
 750         sndbuf->buflen           = bufsiz;
 751         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 752         rcvbuf->head[0].iov_len  = bufsiz;
 753         rcvbuf->tail[0].iov_len  = 0;
 754         rcvbuf->page_len         = 0;
 755         rcvbuf->len              = 0;
 756         rcvbuf->buflen           = bufsiz;
 757
 758         /* Encode header and provided arguments */
 759         encode = task->tk_msg.rpc_proc->p_encode;
 760         if (!(p = call_header(task))) {
 761                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 762                 rpc_exit(task, -EIO);
 763                 return;
 764         }
 765         if (encode == NULL)
 766                 return;
 767
 768         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 769                         task->tk_msg.rpc_argp);
 770         if (task->tk_status == -ENOMEM) {
 771                 /* XXX: Is this sane? */
 772                 rpc_delay(task, 3*HZ);
 773                 task->tk_status = -EAGAIN;
 774         }
 775 }
 776
 777 /*
 778  * 4.   Get the server port number if not yet set
 779  */
 780 static void
 781 call_bind(struct rpc_task *task)
 782 {
 783         struct rpc_clnt *clnt = task->tk_client;
 784         struct rpc_xprt *xprt = task->tk_xprt;
 785
 786         dprintk("RPC: %4d call_bind (status %d)\n",
 787                                 task->tk_pid, task->tk_status);
 788
 789         task->tk_action = call_connect;
 790         if (!xprt_bound(xprt)) {
 791                 task->tk_action = call_bind_status;
 792                 task->tk_timeout = xprt->bind_timeout;
 793                 rpc_getport(task, clnt);
 794         }
 795 }
 796
 797 /*
 798  * 4a.  Sort out bind result
 799  */
 800 static void
 801 call_bind_status(struct rpc_task *task)
 802 {
 803         int status = -EACCES;
 804
 805         if (task->tk_status >= 0) {
 806                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 807                                         task->tk_pid, task->tk_status);
 808                 task->tk_status = 0;
 809                 task->tk_action = call_connect;
 810                 return;
 811         }
 812
 813         switch (task->tk_status) {
 814         case -EACCES:
 815                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
 816                                 task->tk_pid);
 817                 rpc_delay(task, 3*HZ);
 818                 goto retry_bind;
 819         case -ETIMEDOUT:
 820                 dprintk("RPC: %4d rpcbind request timed out\n",
 821                                 task->tk_pid);
 822                 if (RPC_IS_SOFT(task)) {
 823                         status = -EIO;
 824                         break;
 825                 }
 826                 goto retry_bind;
 827         case -EPFNOSUPPORT:
 828                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 829                                 task->tk_pid);
 830                 break;
 831         case -EPROTONOSUPPORT:
 832                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 833                                 task->tk_pid);
 834                 break;
 835         default:
 836                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 837                                 task->tk_pid, -task->tk_status);
 838                 status = -EIO;
 839                 break;
 840         }
 841
 842         rpc_exit(task, status);
 843         return;
 844
 845 retry_bind:
 846         task->tk_status = 0;
 847         task->tk_action = call_bind;
 848         return;
 849 }
 850
 851 /*
 852  * 4b.  Connect to the RPC server
 853  */
 854 static void
 855 call_connect(struct rpc_task *task)
 856 {
 857         struct rpc_xprt *xprt = task->tk_xprt;
 858
 859         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 860                         task->tk_pid, xprt,
 861                         (xprt_connected(xprt) ? "is" : "is not"));
 862
 863         task->tk_action = call_transmit;
 864         if (!xprt_connected(xprt)) {
 865                 task->tk_action = call_connect_status;
 866                 if (task->tk_status < 0)
 867                         return;
 868                 xprt_connect(task);
 869         }
 870 }
 871
 872 /*
 873  * 4c.  Sort out connect result
 874  */
 875 static void
 876 call_connect_status(struct rpc_task *task)
 877 {
 878         struct rpc_clnt *clnt = task->tk_client;
 879         int status = task->tk_status;
 880
 881         dprintk("RPC: %5u call_connect_status (status %d)\n",
 882                                 task->tk_pid, task->tk_status);
 883
 884         task->tk_status = 0;
 885         if (status >= 0) {
 886                 clnt->cl_stats->netreconn++;
 887                 task->tk_action = call_transmit;
 888                 return;
 889         }
 890
 891         /* Something failed: remote service port may have changed */
 892         rpc_force_rebind(clnt);
 893
 894         switch (status) {
 895         case -ENOTCONN:
 896         case -ETIMEDOUT:
 897         case -EAGAIN:
 898                 task->tk_action = call_bind;
 899                 break;
 900         default:
 901                 rpc_exit(task, -EIO);
 902                 break;
 903         }
 904 }
 905
 906 /*
 907  * 5.   Transmit the RPC request, and wait for reply
 908  */
 909 static void
 910 call_transmit(struct rpc_task *task)
 911 {
 912         dprintk("RPC: %4d call_transmit (status %d)\n",
 913                                 task->tk_pid, task->tk_status);
 914
 915         task->tk_action = call_status;
 916         if (task->tk_status < 0)
 917                 return;
 918         task->tk_status = xprt_prepare_transmit(task);
 919         if (task->tk_status != 0)
 920                 return;
 921         task->tk_action = call_transmit_status;
 922         /* Encode here so that rpcsec_gss can use correct sequence number. */
 923         if (rpc_task_need_encode(task)) {
 924                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 925                 call_encode(task);
 926                 /* Did the encode result in an error condition? */
 927                 if (task->tk_status != 0)
 928                         return;
 929         }
 930         xprt_transmit(task);
 931         if (task->tk_status < 0)
 932                 return;
 933         /*
 934          * On success, ensure that we call xprt_end_transmit() before sleeping
 935          * in order to allow access to the socket to other RPC requests.
 936          */
 937         call_transmit_status(task);
 938         if (task->tk_msg.rpc_proc->p_decode != NULL)
 939                 return;
 940         task->tk_action = rpc_exit_task;
 941         rpc_wake_up_task(task);
 942 }
 943
 944 /*
 945  * 5a.  Handle cleanup after a transmission
 946  */
 947 static void
 948 call_transmit_status(struct rpc_task *task)
 949 {
 950         task->tk_action = call_status;
 951         /*
 952          * Special case: if we've been waiting on the socket's write_space()
 953          * callback, then don't call xprt_end_transmit().
 954          */
 955         if (task->tk_status == -EAGAIN)
 956                 return;
 957         xprt_end_transmit(task);
 958         rpc_task_force_reencode(task);
 959 }
 960
 961 /*
 962  * 6.   Sort out the RPC call status
 963  */
 964 static void
 965 call_status(struct rpc_task *task)
 966 {
 967         struct rpc_clnt *clnt = task->tk_client;
 968         struct rpc_rqst *req = task->tk_rqstp;
 969         int             status;
 970
 971         if (req->rq_received > 0 && !req->rq_bytes_sent)
 972                 task->tk_status = req->rq_received;
 973
 974         dprintk("RPC: %4d call_status (status %d)\n",
 975                                 task->tk_pid, task->tk_status);
 976
 977         status = task->tk_status;
 978         if (status >= 0) {
 979                 task->tk_action = call_decode;
 980                 return;
 981         }
 982
 983         task->tk_status = 0;
 984         switch(status) {
 985         case -ETIMEDOUT:
 986                 task->tk_action = call_timeout;
 987                 break;
 988         case -ECONNREFUSED:
 989         case -ENOTCONN:
 990                 rpc_force_rebind(clnt);
 991                 task->tk_action = call_bind;
 992                 break;
 993         case -EAGAIN:
 994                 task->tk_action = call_transmit;
 995                 break;
 996         case -EIO:
 997                 /* shutdown or soft timeout */
 998                 rpc_exit(task, status);
 999                 break;
1000         default:
1001                 printk("%s: RPC call returned error %d\n",
1002                                clnt->cl_protname, -status);
1003                 rpc_exit(task, status);
1004                 break;
1005         }
1006 }
1007
1008 /*
1009  * 6a.  Handle RPC timeout
1010  *      We do not release the request slot, so we keep using the
1011  *      same XID for all retransmits.
1012  */
1013 static void
1014 call_timeout(struct rpc_task *task)
1015 {
1016         struct rpc_clnt *clnt = task->tk_client;
1017
1018         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1019                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1020                 goto retry;
1021         }
1022
1023         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1024         task->tk_timeouts++;
1025
1026         if (RPC_IS_SOFT(task)) {
1027                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1028                                 clnt->cl_protname, clnt->cl_server);
1029                 rpc_exit(task, -EIO);
1030                 return;
1031         }
1032
1033         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1034                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1035                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1036                         clnt->cl_protname, clnt->cl_server);
1037         }
1038         rpc_force_rebind(clnt);
1039
1040 retry:
1041         clnt->cl_stats->rpcretrans++;
1042         task->tk_action = call_bind;
1043         task->tk_status = 0;
1044 }
1045
1046 /*
1047  * 7.   Decode the RPC reply
1048  */
1049 static void
1050 call_decode(struct rpc_task *task)
1051 {
1052         struct rpc_clnt *clnt = task->tk_client;
1053         struct rpc_rqst *req = task->tk_rqstp;
1054         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1055         u32             *p;
1056
1057         dprintk("RPC: %4d call_decode (status %d)\n",
1058                                 task->tk_pid, task->tk_status);
1059
1060         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1061                 printk(KERN_NOTICE "%s: server %s OK\n",
1062                         clnt->cl_protname, clnt->cl_server);
1063                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1064         }
1065
1066         if (task->tk_status < 12) {
1067                 if (!RPC_IS_SOFT(task)) {
1068                         task->tk_action = call_bind;
1069                         clnt->cl_stats->rpcretrans++;
1070                         goto out_retry;
1071                 }
1072                 printk(KERN_WARNING "%s: too small RPC reply size (%d bytes)\n",
1073                         clnt->cl_protname, task->tk_status);
1074                 rpc_exit(task, -EIO);
1075                 return;
1076         }
1077
1078         /*
1079          * Ensure that we see all writes made by xprt_complete_rqst()
1080          * before it changed req->rq_received.
1081          */
1082         smp_rmb();
1083         req->rq_rcv_buf.len = req->rq_private_buf.len;
1084
1085         /* Check that the softirq receive buffer is valid */
1086         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1087                                 sizeof(req->rq_rcv_buf)) != 0);
1088
1089         /* Verify the RPC header */
1090         p = call_verify(task);
1091         if (IS_ERR(p)) {
1092                 if (p == ERR_PTR(-EAGAIN))
1093                         goto out_retry;
1094                 return;
1095         }
1096
1097         task->tk_action = rpc_exit_task;
1098
1099         if (decode)
1100                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1101                                                       task->tk_msg.rpc_resp);
1102         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1103                                         task->tk_status);
1104         return;
1105 out_retry:
1106         req->rq_received = req->rq_private_buf.len = 0;
1107         task->tk_status = 0;
1108 }
1109
1110 /*
1111  * 8.   Refresh the credentials if rejected by the server
1112  */
1113 static void
1114 call_refresh(struct rpc_task *task)
1115 {
1116         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1117
1118         xprt_release(task);     /* Must do to obtain new XID */
1119         task->tk_action = call_refreshresult;
1120         task->tk_status = 0;
1121         task->tk_client->cl_stats->rpcauthrefresh++;
1122         rpcauth_refreshcred(task);
1123 }
1124
1125 /*
1126  * 8a.  Process the results of a credential refresh
1127  */
1128 static void
1129 call_refreshresult(struct rpc_task *task)
1130 {
1131         int status = task->tk_status;
1132         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1133                                 task->tk_pid, task->tk_status);
1134
1135         task->tk_status = 0;
1136         task->tk_action = call_reserve;
1137         if (status >= 0 && rpcauth_uptodatecred(task))
1138                 return;
1139         if (status == -EACCES) {
1140                 rpc_exit(task, -EACCES);
1141                 return;
1142         }
1143         task->tk_action = call_refresh;
1144         if (status != -ETIMEDOUT)
1145                 rpc_delay(task, 3*HZ);
1146         return;
1147 }
1148
1149 /*
1150  * Call header serialization
1151  */
1152 static u32 *
1153 call_header(struct rpc_task *task)
1154 {
1155         struct rpc_clnt *clnt = task->tk_client;
1156         struct rpc_rqst *req = task->tk_rqstp;
1157         u32             *p = req->rq_svec[0].iov_base;
1158
1159         /* FIXME: check buffer size? */
1160
1161         p = xprt_skip_transport_header(task->tk_xprt, p);
1162         *p++ = req->rq_xid;             /* XID */
1163         *p++ = htonl(RPC_CALL);         /* CALL */
1164         *p++ = htonl(RPC_VERSION);      /* RPC version */
1165         *p++ = htonl(clnt->cl_prog);    /* program number */
1166         *p++ = htonl(clnt->cl_vers);    /* program version */
1167         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1168         p = rpcauth_marshcred(task, p);
1169         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1170         return p;
1171 }
1172
1173 /*
1174  * Reply header verification
1175  */
1176 static u32 *
1177 call_verify(struct rpc_task *task)
1178 {
1179         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1180         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1181         u32     *p = iov->iov_base, n;
1182         int error = -EACCES;
1183
1184         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1185                 /* RFC-1014 says that the representation of XDR data must be a
1186                  * multiple of four bytes
1187                  * - if it isn't pointer subtraction in the NFS client may give
1188                  *   undefined results
1189                  */
1190                 printk(KERN_WARNING
1191                        "call_verify: XDR representation not a multiple of"
1192                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1193                 goto out_eio;
1194         }
1195         if ((len -= 3) < 0)
1196                 goto out_overflow;
1197         p += 1; /* skip XID */
1198
1199         if ((n = ntohl(*p++)) != RPC_REPLY) {
1200                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1201                 goto out_garbage;
1202         }
1203         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1204                 if (--len < 0)
1205                         goto out_overflow;
1206                 switch ((n = ntohl(*p++))) {
1207                         case RPC_AUTH_ERROR:
1208                                 break;
1209                         case RPC_MISMATCH:
1210                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1211                                 error = -EPROTONOSUPPORT;
1212                                 goto out_err;
1213                         default:
1214                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1215                                 goto out_eio;
1216                 }
1217                 if (--len < 0)
1218                         goto out_overflow;
1219                 switch ((n = ntohl(*p++))) {
1220                 case RPC_AUTH_REJECTEDCRED:
1221                 case RPC_AUTH_REJECTEDVERF:
1222                 case RPCSEC_GSS_CREDPROBLEM:
1223                 case RPCSEC_GSS_CTXPROBLEM:
1224                         if (!task->tk_cred_retry)
1225                                 break;
1226                         task->tk_cred_retry--;
1227                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1228                                                         task->tk_pid);
1229                         rpcauth_invalcred(task);
1230                         task->tk_action = call_refresh;
1231                         goto out_retry;
1232                 case RPC_AUTH_BADCRED:
1233                 case RPC_AUTH_BADVERF:
1234                         /* possibly garbled cred/verf? */
1235                         if (!task->tk_garb_retry)
1236                                 break;
1237                         task->tk_garb_retry--;
1238                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1239                                                         task->tk_pid);
1240                         task->tk_action = call_bind;
1241                         goto out_retry;
1242                 case RPC_AUTH_TOOWEAK:
1243                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1244                                "authentication.\n", task->tk_client->cl_server);
1245                         break;
1246                 default:
1247                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1248                         error = -EIO;
1249                 }
1250                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1251                                                 task->tk_pid, n);
1252                 goto out_err;
1253         }
1254         if (!(p = rpcauth_checkverf(task, p))) {
1255                 printk(KERN_WARNING "call_verify: auth check failed\n");
1256                 goto out_garbage;               /* bad verifier, retry */
1257         }
1258         len = p - (u32 *)iov->iov_base - 1;
1259         if (len < 0)
1260                 goto out_overflow;
1261         switch ((n = ntohl(*p++))) {
1262         case RPC_SUCCESS:
1263                 return p;
1264         case RPC_PROG_UNAVAIL:
1265                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1266                                 (unsigned int)task->tk_client->cl_prog,
1267                                 task->tk_client->cl_server);
1268                 error = -EPFNOSUPPORT;
1269                 goto out_err;
1270         case RPC_PROG_MISMATCH:
1271                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1272                                 (unsigned int)task->tk_client->cl_prog,
1273                                 (unsigned int)task->tk_client->cl_vers,
1274                                 task->tk_client->cl_server);
1275                 error = -EPROTONOSUPPORT;
1276                 goto out_err;
1277         case RPC_PROC_UNAVAIL:
1278                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1279                                 task->tk_msg.rpc_proc,
1280                                 task->tk_client->cl_prog,
1281                                 task->tk_client->cl_vers,
1282                                 task->tk_client->cl_server);
1283                 error = -EOPNOTSUPP;
1284                 goto out_err;
1285         case RPC_GARBAGE_ARGS:
1286                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1287                 break;                  /* retry */
1288         default:
1289                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1290                 /* Also retry */
1291         }
1292
1293 out_garbage:
1294         task->tk_client->cl_stats->rpcgarbage++;
1295         if (task->tk_garb_retry) {
1296                 task->tk_garb_retry--;
1297                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1298                 task->tk_action = call_bind;
1299 out_retry:
1300                 return ERR_PTR(-EAGAIN);
1301         }
1302         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1303 out_eio:
1304         error = -EIO;
1305 out_err:
1306         rpc_exit(task, error);
1307         return ERR_PTR(error);
1308 out_overflow:
1309         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1310         goto out_garbage;
1311 }
1312
1313 static int rpcproc_encode_null(void *rqstp, u32 *data, void *obj)
1314 {
1315         return 0;
1316 }
1317
1318 static int rpcproc_decode_null(void *rqstp, u32 *data, void *obj)
1319 {
1320         return 0;
1321 }
1322
1323 static struct rpc_procinfo rpcproc_null = {
1324         .p_encode = rpcproc_encode_null,
1325         .p_decode = rpcproc_decode_null,
1326 };
1327
1328 int rpc_ping(struct rpc_clnt *clnt, int flags)
1329 {
1330         struct rpc_message msg = {
1331                 .rpc_proc = &rpcproc_null,
1332         };
1333         int err;
1334         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1335         err = rpc_call_sync(clnt, &msg, flags);
1336         put_rpccred(msg.rpc_cred);
1337         return err;
1338 }