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   1 /*
   2  *  linux/net/sunrpc/clnt.c
   3  *
   4  *  This file contains the high-level RPC interface.
   5  *  It is modeled as a finite state machine to support both synchronous
   6  *  and asynchronous requests.
   7  *
   8  *  -   RPC header generation and argument serialization.
   9  *  -   Credential refresh.
  10  *  -   TCP connect handling.
  11  *  -   Retry of operation when it is suspected the operation failed because
  12  *      of uid squashing on the server, or when the credentials were stale
  13  *      and need to be refreshed, or when a packet was damaged in transit.
  14  *      This may be have to be moved to the VFS layer.
  15  *
  16  *  NB: BSD uses a more intelligent approach to guessing when a request
  17  *  or reply has been lost by keeping the RTO estimate for each procedure.
  18  *  We currently make do with a constant timeout value.
  19  *
  20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  22  */
  23
  24 #include <asm/system.h>
  25
  26 #include <linux/module.h>
  27 #include <linux/types.h>
  28 #include <linux/mm.h>
  29 #include <linux/slab.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/utsname.h>
  32 #include <linux/workqueue.h>
  33
  34 #include <linux/sunrpc/clnt.h>
  35 #include <linux/sunrpc/rpc_pipe_fs.h>
  36 #include <linux/sunrpc/metrics.h>
  37
  38
  39 #ifdef RPC_DEBUG
  40 # define RPCDBG_FACILITY        RPCDBG_CALL
  41 #endif
  42
  43 #define dprint_status(t)                                        \
  44         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  45                         __FUNCTION__, t->tk_status)
  46
  47 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  48
  49
  50 static void     call_start(struct rpc_task *task);
  51 static void     call_reserve(struct rpc_task *task);
  52 static void     call_reserveresult(struct rpc_task *task);
  53 static void     call_allocate(struct rpc_task *task);
  54 static void     call_encode(struct rpc_task *task);
  55 static void     call_decode(struct rpc_task *task);
  56 static void     call_bind(struct rpc_task *task);
  57 static void     call_bind_status(struct rpc_task *task);
  58 static void     call_transmit(struct rpc_task *task);
  59 static void     call_status(struct rpc_task *task);
  60 static void     call_transmit_status(struct rpc_task *task);
  61 static void     call_refresh(struct rpc_task *task);
  62 static void     call_refreshresult(struct rpc_task *task);
  63 static void     call_timeout(struct rpc_task *task);
  64 static void     call_connect(struct rpc_task *task);
  65 static void     call_connect_status(struct rpc_task *task);
  66 static __be32 * call_header(struct rpc_task *task);
  67 static __be32 * call_verify(struct rpc_task *task);
  68
  69
  70 static int
  71 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  72 {
  73         static uint32_t clntid;
  74         int error;
  75
  76         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  77         clnt->cl_dentry = ERR_PTR(-ENOENT);
  78         if (dir_name == NULL)
  79                 return 0;
  80
  81         clnt->cl_vfsmnt = rpc_get_mount();
  82         if (IS_ERR(clnt->cl_vfsmnt))
  83                 return PTR_ERR(clnt->cl_vfsmnt);
  84
  85         for (;;) {
  86                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  87                                 "%s/clnt%x", dir_name,
  88                                 (unsigned int)clntid++);
  89                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  90                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  91                 if (!IS_ERR(clnt->cl_dentry))
  92                         return 0;
  93                 error = PTR_ERR(clnt->cl_dentry);
  94                 if (error != -EEXIST) {
  95                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  96                                         clnt->cl_pathname, error);
  97                         rpc_put_mount();
  98                         return error;
  99                 }
 100         }
 101 }
 102
 103 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
 104 {
 105         struct rpc_version      *version;
 106         struct rpc_clnt         *clnt = NULL;
 107         struct rpc_auth         *auth;
 108         int err;
 109         int len;
 110
 111         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 112                         program->name, servname, xprt);
 113
 114         err = rpciod_up();
 115         if (err)
 116                 goto out_no_rpciod;
 117         err = -EINVAL;
 118         if (!xprt)
 119                 goto out_no_xprt;
 120         if (vers >= program->nrvers || !(version = program->version[vers]))
 121                 goto out_err;
 122
 123         err = -ENOMEM;
 124         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 125         if (!clnt)
 126                 goto out_err;
 127         clnt->cl_parent = clnt;
 128
 129         clnt->cl_server = clnt->cl_inline_name;
 130         len = strlen(servname) + 1;
 131         if (len > sizeof(clnt->cl_inline_name)) {
 132                 char *buf = kmalloc(len, GFP_KERNEL);
 133                 if (buf != 0)
 134                         clnt->cl_server = buf;
 135                 else
 136                         len = sizeof(clnt->cl_inline_name);
 137         }
 138         strlcpy(clnt->cl_server, servname, len);
 139
 140         clnt->cl_xprt     = xprt;
 141         clnt->cl_procinfo = version->procs;
 142         clnt->cl_maxproc  = version->nrprocs;
 143         clnt->cl_protname = program->name;
 144         clnt->cl_prog     = program->number;
 145         clnt->cl_vers     = version->number;
 146         clnt->cl_stats    = program->stats;
 147         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 148         err = -ENOMEM;
 149         if (clnt->cl_metrics == NULL)
 150                 goto out_no_stats;
 151         clnt->cl_program  = program;
 152         INIT_LIST_HEAD(&clnt->cl_tasks);
 153         spin_lock_init(&clnt->cl_lock);
 154
 155         if (!xprt_bound(clnt->cl_xprt))
 156                 clnt->cl_autobind = 1;
 157
 158         clnt->cl_rtt = &clnt->cl_rtt_default;
 159         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 160
 161         kref_init(&clnt->cl_kref);
 162
 163         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 164         if (err < 0)
 165                 goto out_no_path;
 166
 167         auth = rpcauth_create(flavor, clnt);
 168         if (IS_ERR(auth)) {
 169                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 170                                 flavor);
 171                 err = PTR_ERR(auth);
 172                 goto out_no_auth;
 173         }
 174
 175         /* save the nodename */
 176         clnt->cl_nodelen = strlen(utsname()->nodename);
 177         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 178                 clnt->cl_nodelen = UNX_MAXNODENAME;
 179         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 180         rpc_register_client(clnt);
 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         rpc_free_iostats(clnt->cl_metrics);
 190 out_no_stats:
 191         if (clnt->cl_server != clnt->cl_inline_name)
 192                 kfree(clnt->cl_server);
 193         kfree(clnt);
 194 out_err:
 195         xprt_put(xprt);
 196 out_no_xprt:
 197         rpciod_down();
 198 out_no_rpciod:
 199         return ERR_PTR(err);
 200 }
 201
 202 /*
 203  * rpc_create - create an RPC client and transport with one call
 204  * @args: rpc_clnt create argument structure
 205  *
 206  * Creates and initializes an RPC transport and an RPC client.
 207  *
 208  * It can ping the server in order to determine if it is up, and to see if
 209  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 210  * this behavior so asynchronous tasks can also use rpc_create.
 211  */
 212 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 213 {
 214         struct rpc_xprt *xprt;
 215         struct rpc_clnt *clnt;
 216
 217         xprt = xprt_create_transport(args->protocol, args->address,
 218                                         args->addrsize, args->timeout);
 219         if (IS_ERR(xprt))
 220                 return (struct rpc_clnt *)xprt;
 221
 222         /*
 223          * By default, kernel RPC client connects from a reserved port.
 224          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 225          * but it is always enabled for rpciod, which handles the connect
 226          * operation.
 227          */
 228         xprt->resvport = 1;
 229         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 230                 xprt->resvport = 0;
 231
 232         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 233                         args->program->name, args->servername, xprt);
 234
 235         clnt = rpc_new_client(xprt, args->servername, args->program,
 236                                 args->version, args->authflavor);
 237         if (IS_ERR(clnt))
 238                 return clnt;
 239
 240         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 241                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 242                 if (err != 0) {
 243                         rpc_shutdown_client(clnt);
 244                         return ERR_PTR(err);
 245                 }
 246         }
 247
 248         clnt->cl_softrtry = 1;
 249         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 250                 clnt->cl_softrtry = 0;
 251
 252         if (args->flags & RPC_CLNT_CREATE_INTR)
 253                 clnt->cl_intr = 1;
 254         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 255                 clnt->cl_autobind = 1;
 256         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 257                 clnt->cl_discrtry = 1;
 258
 259         return clnt;
 260 }
 261 EXPORT_SYMBOL_GPL(rpc_create);
 262
 263 /*
 264  * This function clones the RPC client structure. It allows us to share the
 265  * same transport while varying parameters such as the authentication
 266  * flavour.
 267  */
 268 struct rpc_clnt *
 269 rpc_clone_client(struct rpc_clnt *clnt)
 270 {
 271         struct rpc_clnt *new;
 272         int err = -ENOMEM;
 273
 274         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 275         if (!new)
 276                 goto out_no_clnt;
 277         new->cl_parent = clnt;
 278         /* Turn off autobind on clones */
 279         new->cl_autobind = 0;
 280         INIT_LIST_HEAD(&new->cl_tasks);
 281         spin_lock_init(&new->cl_lock);
 282         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 283         new->cl_metrics = rpc_alloc_iostats(clnt);
 284         if (new->cl_metrics == NULL)
 285                 goto out_no_stats;
 286         kref_init(&new->cl_kref);
 287         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 288         if (err != 0)
 289                 goto out_no_path;
 290         if (new->cl_auth)
 291                 atomic_inc(&new->cl_auth->au_count);
 292         xprt_get(clnt->cl_xprt);
 293         kref_get(&clnt->cl_kref);
 294         rpc_register_client(new);
 295         rpciod_up();
 296         return new;
 297 out_no_path:
 298         rpc_free_iostats(new->cl_metrics);
 299 out_no_stats:
 300         kfree(new);
 301 out_no_clnt:
 302         dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
 303         return ERR_PTR(err);
 304 }
 305
 306 /*
 307  * Properly shut down an RPC client, terminating all outstanding
 308  * requests.
 309  */
 310 void rpc_shutdown_client(struct rpc_clnt *clnt)
 311 {
 312         dprintk("RPC:       shutting down %s client for %s\n",
 313                         clnt->cl_protname, clnt->cl_server);
 314
 315         while (!list_empty(&clnt->cl_tasks)) {
 316                 rpc_killall_tasks(clnt);
 317                 wait_event_timeout(destroy_wait,
 318                         list_empty(&clnt->cl_tasks), 1*HZ);
 319         }
 320
 321         rpc_release_client(clnt);
 322 }
 323
 324 /*
 325  * Free an RPC client
 326  */
 327 static void
 328 rpc_free_client(struct kref *kref)
 329 {
 330         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 331
 332         dprintk("RPC:       destroying %s client for %s\n",
 333                         clnt->cl_protname, clnt->cl_server);
 334         if (clnt->cl_auth) {
 335                 rpcauth_destroy(clnt->cl_auth);
 336                 clnt->cl_auth = NULL;
 337         }
 338         if (!IS_ERR(clnt->cl_dentry)) {
 339                 rpc_rmdir(clnt->cl_dentry);
 340                 rpc_put_mount();
 341         }
 342         if (clnt->cl_parent != clnt) {
 343                 rpc_release_client(clnt->cl_parent);
 344                 goto out_free;
 345         }
 346         if (clnt->cl_server != clnt->cl_inline_name)
 347                 kfree(clnt->cl_server);
 348 out_free:
 349         rpc_unregister_client(clnt);
 350         rpc_free_iostats(clnt->cl_metrics);
 351         clnt->cl_metrics = NULL;
 352         xprt_put(clnt->cl_xprt);
 353         rpciod_down();
 354         kfree(clnt);
 355 }
 356
 357 /*
 358  * Release reference to the RPC client
 359  */
 360 void
 361 rpc_release_client(struct rpc_clnt *clnt)
 362 {
 363         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 364
 365         if (list_empty(&clnt->cl_tasks))
 366                 wake_up(&destroy_wait);
 367         kref_put(&clnt->cl_kref, rpc_free_client);
 368 }
 369
 370 /**
 371  * rpc_bind_new_program - bind a new RPC program to an existing client
 372  * @old - old rpc_client
 373  * @program - rpc program to set
 374  * @vers - rpc program version
 375  *
 376  * Clones the rpc client and sets up a new RPC program. This is mainly
 377  * of use for enabling different RPC programs to share the same transport.
 378  * The Sun NFSv2/v3 ACL protocol can do this.
 379  */
 380 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 381                                       struct rpc_program *program,
 382                                       int vers)
 383 {
 384         struct rpc_clnt *clnt;
 385         struct rpc_version *version;
 386         int err;
 387
 388         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 389         version = program->version[vers];
 390         clnt = rpc_clone_client(old);
 391         if (IS_ERR(clnt))
 392                 goto out;
 393         clnt->cl_procinfo = version->procs;
 394         clnt->cl_maxproc  = version->nrprocs;
 395         clnt->cl_protname = program->name;
 396         clnt->cl_prog     = program->number;
 397         clnt->cl_vers     = version->number;
 398         clnt->cl_stats    = program->stats;
 399         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 400         if (err != 0) {
 401                 rpc_shutdown_client(clnt);
 402                 clnt = ERR_PTR(err);
 403         }
 404 out:
 405         return clnt;
 406 }
 407
 408 /*
 409  * Default callback for async RPC calls
 410  */
 411 static void
 412 rpc_default_callback(struct rpc_task *task, void *data)
 413 {
 414 }
 415
 416 static const struct rpc_call_ops rpc_default_ops = {
 417         .rpc_call_done = rpc_default_callback,
 418 };
 419
 420 /*
 421  *      Export the signal mask handling for synchronous code that
 422  *      sleeps on RPC calls
 423  */
 424 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 425
 426 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 427 {
 428         unsigned long   sigallow = sigmask(SIGKILL);
 429         sigset_t sigmask;
 430
 431         /* Block all signals except those listed in sigallow */
 432         if (intr)
 433                 sigallow |= RPC_INTR_SIGNALS;
 434         siginitsetinv(&sigmask, sigallow);
 435         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 436 }
 437
 438 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 439 {
 440         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 441 }
 442
 443 static inline void rpc_restore_sigmask(sigset_t *oldset)
 444 {
 445         sigprocmask(SIG_SETMASK, oldset, NULL);
 446 }
 447
 448 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 449 {
 450         rpc_save_sigmask(oldset, clnt->cl_intr);
 451 }
 452
 453 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 454 {
 455         rpc_restore_sigmask(oldset);
 456 }
 457
 458 /*
 459  * New rpc_call implementation
 460  */
 461 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 462 {
 463         struct rpc_task *task;
 464         sigset_t        oldset;
 465         int             status;
 466
 467         BUG_ON(flags & RPC_TASK_ASYNC);
 468
 469         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 470         if (task == NULL)
 471                 return -ENOMEM;
 472
 473         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 474         rpc_task_sigmask(task, &oldset);
 475
 476         /* Set up the call info struct and execute the task */
 477         rpc_call_setup(task, msg, 0);
 478         if (task->tk_status == 0) {
 479                 atomic_inc(&task->tk_count);
 480                 rpc_execute(task);
 481         }
 482         status = task->tk_status;
 483         rpc_put_task(task);
 484         rpc_restore_sigmask(&oldset);
 485         return status;
 486 }
 487
 488 /*
 489  * New rpc_call implementation
 490  */
 491 int
 492 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 493                const struct rpc_call_ops *tk_ops, void *data)
 494 {
 495         struct rpc_task *task;
 496         sigset_t        oldset;
 497         int             status;
 498
 499         flags |= RPC_TASK_ASYNC;
 500
 501         /* Create/initialize a new RPC task */
 502         status = -ENOMEM;
 503         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 504                 goto out_release;
 505
 506         /* Mask signals on GSS_AUTH upcalls */
 507         rpc_task_sigmask(task, &oldset);
 508
 509         rpc_call_setup(task, msg, 0);
 510
 511         /* Set up the call info struct and execute the task */
 512         status = task->tk_status;
 513         if (status == 0)
 514                 rpc_execute(task);
 515         else
 516                 rpc_put_task(task);
 517
 518         rpc_restore_sigmask(&oldset);
 519         return status;
 520 out_release:
 521         rpc_release_calldata(tk_ops, data);
 522         return status;
 523 }
 524
 525
 526 void
 527 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 528 {
 529         task->tk_msg   = *msg;
 530         task->tk_flags |= flags;
 531         /* Bind the user cred */
 532         if (task->tk_msg.rpc_cred != NULL)
 533                 rpcauth_holdcred(task);
 534         else
 535                 rpcauth_bindcred(task);
 536
 537         if (task->tk_status == 0)
 538                 task->tk_action = call_start;
 539         else
 540                 task->tk_action = rpc_exit_task;
 541 }
 542
 543 /**
 544  * rpc_peeraddr - extract remote peer address from clnt's xprt
 545  * @clnt: RPC client structure
 546  * @buf: target buffer
 547  * @size: length of target buffer
 548  *
 549  * Returns the number of bytes that are actually in the stored address.
 550  */
 551 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 552 {
 553         size_t bytes;
 554         struct rpc_xprt *xprt = clnt->cl_xprt;
 555
 556         bytes = sizeof(xprt->addr);
 557         if (bytes > bufsize)
 558                 bytes = bufsize;
 559         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 560         return xprt->addrlen;
 561 }
 562 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 563
 564 /**
 565  * rpc_peeraddr2str - return remote peer address in printable format
 566  * @clnt: RPC client structure
 567  * @format: address format
 568  *
 569  */
 570 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 571 {
 572         struct rpc_xprt *xprt = clnt->cl_xprt;
 573
 574         if (xprt->address_strings[format] != NULL)
 575                 return xprt->address_strings[format];
 576         else
 577                 return "unprintable";
 578 }
 579 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 580
 581 void
 582 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 583 {
 584         struct rpc_xprt *xprt = clnt->cl_xprt;
 585         if (xprt->ops->set_buffer_size)
 586                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 587 }
 588
 589 /*
 590  * Return size of largest payload RPC client can support, in bytes
 591  *
 592  * For stream transports, this is one RPC record fragment (see RFC
 593  * 1831), as we don't support multi-record requests yet.  For datagram
 594  * transports, this is the size of an IP packet minus the IP, UDP, and
 595  * RPC header sizes.
 596  */
 597 size_t rpc_max_payload(struct rpc_clnt *clnt)
 598 {
 599         return clnt->cl_xprt->max_payload;
 600 }
 601 EXPORT_SYMBOL_GPL(rpc_max_payload);
 602
 603 /**
 604  * rpc_force_rebind - force transport to check that remote port is unchanged
 605  * @clnt: client to rebind
 606  *
 607  */
 608 void rpc_force_rebind(struct rpc_clnt *clnt)
 609 {
 610         if (clnt->cl_autobind)
 611                 xprt_clear_bound(clnt->cl_xprt);
 612 }
 613 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 614
 615 /*
 616  * Restart an (async) RPC call. Usually called from within the
 617  * exit handler.
 618  */
 619 void
 620 rpc_restart_call(struct rpc_task *task)
 621 {
 622         if (RPC_ASSASSINATED(task))
 623                 return;
 624
 625         task->tk_action = call_start;
 626 }
 627
 628 /*
 629  * 0.  Initial state
 630  *
 631  *     Other FSM states can be visited zero or more times, but
 632  *     this state is visited exactly once for each RPC.
 633  */
 634 static void
 635 call_start(struct rpc_task *task)
 636 {
 637         struct rpc_clnt *clnt = task->tk_client;
 638
 639         dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
 640                         clnt->cl_protname, clnt->cl_vers,
 641                         task->tk_msg.rpc_proc->p_proc,
 642                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 643
 644         /* Increment call count */
 645         task->tk_msg.rpc_proc->p_count++;
 646         clnt->cl_stats->rpccnt++;
 647         task->tk_action = call_reserve;
 648 }
 649
 650 /*
 651  * 1.   Reserve an RPC call slot
 652  */
 653 static void
 654 call_reserve(struct rpc_task *task)
 655 {
 656         dprint_status(task);
 657
 658         if (!rpcauth_uptodatecred(task)) {
 659                 task->tk_action = call_refresh;
 660                 return;
 661         }
 662
 663         task->tk_status  = 0;
 664         task->tk_action  = call_reserveresult;
 665         xprt_reserve(task);
 666 }
 667
 668 /*
 669  * 1b.  Grok the result of xprt_reserve()
 670  */
 671 static void
 672 call_reserveresult(struct rpc_task *task)
 673 {
 674         int status = task->tk_status;
 675
 676         dprint_status(task);
 677
 678         /*
 679          * After a call to xprt_reserve(), we must have either
 680          * a request slot or else an error status.
 681          */
 682         task->tk_status = 0;
 683         if (status >= 0) {
 684                 if (task->tk_rqstp) {
 685                         task->tk_action = call_allocate;
 686                         return;
 687                 }
 688
 689                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 690                                 __FUNCTION__, status);
 691                 rpc_exit(task, -EIO);
 692                 return;
 693         }
 694
 695         /*
 696          * Even though there was an error, we may have acquired
 697          * a request slot somehow.  Make sure not to leak it.
 698          */
 699         if (task->tk_rqstp) {
 700                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 701                                 __FUNCTION__, status);
 702                 xprt_release(task);
 703         }
 704
 705         switch (status) {
 706         case -EAGAIN:   /* woken up; retry */
 707                 task->tk_action = call_reserve;
 708                 return;
 709         case -EIO:      /* probably a shutdown */
 710                 break;
 711         default:
 712                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 713                                 __FUNCTION__, status);
 714                 break;
 715         }
 716         rpc_exit(task, status);
 717 }
 718
 719 /*
 720  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 721  *      (Note: buffer memory is freed in xprt_release).
 722  */
 723 static void
 724 call_allocate(struct rpc_task *task)
 725 {
 726         unsigned int slack = task->tk_auth->au_cslack;
 727         struct rpc_rqst *req = task->tk_rqstp;
 728         struct rpc_xprt *xprt = task->tk_xprt;
 729         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 730
 731         dprint_status(task);
 732
 733         task->tk_status = 0;
 734         task->tk_action = call_bind;
 735
 736         if (req->rq_buffer)
 737                 return;
 738
 739         if (proc->p_proc != 0) {
 740                 BUG_ON(proc->p_arglen == 0);
 741                 if (proc->p_decode != NULL)
 742                         BUG_ON(proc->p_replen == 0);
 743         }
 744
 745         /*
 746          * Calculate the size (in quads) of the RPC call
 747          * and reply headers, and convert both values
 748          * to byte sizes.
 749          */
 750         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
 751         req->rq_callsize <<= 2;
 752         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
 753         req->rq_rcvsize <<= 2;
 754
 755         req->rq_buffer = xprt->ops->buf_alloc(task,
 756                                         req->rq_callsize + req->rq_rcvsize);
 757         if (req->rq_buffer != NULL)
 758                 return;
 759
 760         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
 761
 762         if (RPC_IS_ASYNC(task) || !signalled()) {
 763                 xprt_release(task);
 764                 task->tk_action = call_reserve;
 765                 rpc_delay(task, HZ>>4);
 766                 return;
 767         }
 768
 769         rpc_exit(task, -ERESTARTSYS);
 770 }
 771
 772 static inline int
 773 rpc_task_need_encode(struct rpc_task *task)
 774 {
 775         return task->tk_rqstp->rq_snd_buf.len == 0;
 776 }
 777
 778 static inline void
 779 rpc_task_force_reencode(struct rpc_task *task)
 780 {
 781         task->tk_rqstp->rq_snd_buf.len = 0;
 782 }
 783
 784 static inline void
 785 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
 786 {
 787         buf->head[0].iov_base = start;
 788         buf->head[0].iov_len = len;
 789         buf->tail[0].iov_len = 0;
 790         buf->page_len = 0;
 791         buf->len = 0;
 792         buf->buflen = len;
 793 }
 794
 795 /*
 796  * 3.   Encode arguments of an RPC call
 797  */
 798 static void
 799 call_encode(struct rpc_task *task)
 800 {
 801         struct rpc_rqst *req = task->tk_rqstp;
 802         kxdrproc_t      encode;
 803         __be32          *p;
 804
 805         dprint_status(task);
 806
 807         rpc_xdr_buf_init(&req->rq_snd_buf,
 808                          req->rq_buffer,
 809                          req->rq_callsize);
 810         rpc_xdr_buf_init(&req->rq_rcv_buf,
 811                          (char *)req->rq_buffer + req->rq_callsize,
 812                          req->rq_rcvsize);
 813
 814         /* Encode header and provided arguments */
 815         encode = task->tk_msg.rpc_proc->p_encode;
 816         if (!(p = call_header(task))) {
 817                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 818                 rpc_exit(task, -EIO);
 819                 return;
 820         }
 821         if (encode == NULL)
 822                 return;
 823
 824         lock_kernel();
 825         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 826                         task->tk_msg.rpc_argp);
 827         unlock_kernel();
 828         if (task->tk_status == -ENOMEM) {
 829                 /* XXX: Is this sane? */
 830                 rpc_delay(task, 3*HZ);
 831                 task->tk_status = -EAGAIN;
 832         }
 833 }
 834
 835 /*
 836  * 4.   Get the server port number if not yet set
 837  */
 838 static void
 839 call_bind(struct rpc_task *task)
 840 {
 841         struct rpc_xprt *xprt = task->tk_xprt;
 842
 843         dprint_status(task);
 844
 845         task->tk_action = call_connect;
 846         if (!xprt_bound(xprt)) {
 847                 task->tk_action = call_bind_status;
 848                 task->tk_timeout = xprt->bind_timeout;
 849                 xprt->ops->rpcbind(task);
 850         }
 851 }
 852
 853 /*
 854  * 4a.  Sort out bind result
 855  */
 856 static void
 857 call_bind_status(struct rpc_task *task)
 858 {
 859         int status = -EACCES;
 860
 861         if (task->tk_status >= 0) {
 862                 dprint_status(task);
 863                 task->tk_status = 0;
 864                 task->tk_action = call_connect;
 865                 return;
 866         }
 867
 868         switch (task->tk_status) {
 869         case -EACCES:
 870                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
 871                                 "unavailable\n", task->tk_pid);
 872                 rpc_delay(task, 3*HZ);
 873                 goto retry_timeout;
 874         case -ETIMEDOUT:
 875                 dprintk("RPC: %5u rpcbind request timed out\n",
 876                                 task->tk_pid);
 877                 goto retry_timeout;
 878         case -EPFNOSUPPORT:
 879                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
 880                                 task->tk_pid);
 881                 break;
 882         case -EPROTONOSUPPORT:
 883                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
 884                                 task->tk_pid);
 885                 task->tk_status = 0;
 886                 task->tk_action = call_bind;
 887                 return;
 888         default:
 889                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 890                                 task->tk_pid, -task->tk_status);
 891                 status = -EIO;
 892         }
 893
 894         rpc_exit(task, status);
 895         return;
 896
 897 retry_timeout:
 898         task->tk_action = call_timeout;
 899 }
 900
 901 /*
 902  * 4b.  Connect to the RPC server
 903  */
 904 static void
 905 call_connect(struct rpc_task *task)
 906 {
 907         struct rpc_xprt *xprt = task->tk_xprt;
 908
 909         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
 910                         task->tk_pid, xprt,
 911                         (xprt_connected(xprt) ? "is" : "is not"));
 912
 913         task->tk_action = call_transmit;
 914         if (!xprt_connected(xprt)) {
 915                 task->tk_action = call_connect_status;
 916                 if (task->tk_status < 0)
 917                         return;
 918                 xprt_connect(task);
 919         }
 920 }
 921
 922 /*
 923  * 4c.  Sort out connect result
 924  */
 925 static void
 926 call_connect_status(struct rpc_task *task)
 927 {
 928         struct rpc_clnt *clnt = task->tk_client;
 929         int status = task->tk_status;
 930
 931         dprint_status(task);
 932
 933         task->tk_status = 0;
 934         if (status >= 0) {
 935                 clnt->cl_stats->netreconn++;
 936                 task->tk_action = call_transmit;
 937                 return;
 938         }
 939
 940         /* Something failed: remote service port may have changed */
 941         rpc_force_rebind(clnt);
 942
 943         switch (status) {
 944         case -ENOTCONN:
 945         case -EAGAIN:
 946                 task->tk_action = call_bind;
 947                 if (!RPC_IS_SOFT(task))
 948                         return;
 949                 /* if soft mounted, test if we've timed out */
 950         case -ETIMEDOUT:
 951                 task->tk_action = call_timeout;
 952                 return;
 953         }
 954         rpc_exit(task, -EIO);
 955 }
 956
 957 /*
 958  * 5.   Transmit the RPC request, and wait for reply
 959  */
 960 static void
 961 call_transmit(struct rpc_task *task)
 962 {
 963         dprint_status(task);
 964
 965         task->tk_action = call_status;
 966         if (task->tk_status < 0)
 967                 return;
 968         task->tk_status = xprt_prepare_transmit(task);
 969         if (task->tk_status != 0)
 970                 return;
 971         task->tk_action = call_transmit_status;
 972         /* Encode here so that rpcsec_gss can use correct sequence number. */
 973         if (rpc_task_need_encode(task)) {
 974                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 975                 call_encode(task);
 976                 /* Did the encode result in an error condition? */
 977                 if (task->tk_status != 0)
 978                         return;
 979         }
 980         xprt_transmit(task);
 981         if (task->tk_status < 0)
 982                 return;
 983         /*
 984          * On success, ensure that we call xprt_end_transmit() before sleeping
 985          * in order to allow access to the socket to other RPC requests.
 986          */
 987         call_transmit_status(task);
 988         if (task->tk_msg.rpc_proc->p_decode != NULL)
 989                 return;
 990         task->tk_action = rpc_exit_task;
 991         rpc_wake_up_task(task);
 992 }
 993
 994 /*
 995  * 5a.  Handle cleanup after a transmission
 996  */
 997 static void
 998 call_transmit_status(struct rpc_task *task)
 999 {
1000         task->tk_action = call_status;
1001         /*
1002          * Special case: if we've been waiting on the socket's write_space()
1003          * callback, then don't call xprt_end_transmit().
1004          */
1005         if (task->tk_status == -EAGAIN)
1006                 return;
1007         xprt_end_transmit(task);
1008         rpc_task_force_reencode(task);
1009 }
1010
1011 /*
1012  * 6.   Sort out the RPC call status
1013  */
1014 static void
1015 call_status(struct rpc_task *task)
1016 {
1017         struct rpc_clnt *clnt = task->tk_client;
1018         struct rpc_rqst *req = task->tk_rqstp;
1019         int             status;
1020
1021         if (req->rq_received > 0 && !req->rq_bytes_sent)
1022                 task->tk_status = req->rq_received;
1023
1024         dprint_status(task);
1025
1026         status = task->tk_status;
1027         if (status >= 0) {
1028                 task->tk_action = call_decode;
1029                 return;
1030         }
1031
1032         task->tk_status = 0;
1033         switch(status) {
1034         case -EHOSTDOWN:
1035         case -EHOSTUNREACH:
1036         case -ENETUNREACH:
1037                 /*
1038                  * Delay any retries for 3 seconds, then handle as if it
1039                  * were a timeout.
1040                  */
1041                 rpc_delay(task, 3*HZ);
1042         case -ETIMEDOUT:
1043                 task->tk_action = call_timeout;
1044                 if (task->tk_client->cl_discrtry)
1045                         xprt_disconnect(task->tk_xprt);
1046                 break;
1047         case -ECONNREFUSED:
1048         case -ENOTCONN:
1049                 rpc_force_rebind(clnt);
1050                 task->tk_action = call_bind;
1051                 break;
1052         case -EAGAIN:
1053                 task->tk_action = call_transmit;
1054                 break;
1055         case -EIO:
1056                 /* shutdown or soft timeout */
1057                 rpc_exit(task, status);
1058                 break;
1059         default:
1060                 printk("%s: RPC call returned error %d\n",
1061                                clnt->cl_protname, -status);
1062                 rpc_exit(task, status);
1063         }
1064 }
1065
1066 /*
1067  * 6a.  Handle RPC timeout
1068  *      We do not release the request slot, so we keep using the
1069  *      same XID for all retransmits.
1070  */
1071 static void
1072 call_timeout(struct rpc_task *task)
1073 {
1074         struct rpc_clnt *clnt = task->tk_client;
1075
1076         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1077                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1078                 goto retry;
1079         }
1080
1081         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1082         task->tk_timeouts++;
1083
1084         if (RPC_IS_SOFT(task)) {
1085                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1086                                 clnt->cl_protname, clnt->cl_server);
1087                 rpc_exit(task, -EIO);
1088                 return;
1089         }
1090
1091         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1092                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1093                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1094                         clnt->cl_protname, clnt->cl_server);
1095         }
1096         rpc_force_rebind(clnt);
1097
1098 retry:
1099         clnt->cl_stats->rpcretrans++;
1100         task->tk_action = call_bind;
1101         task->tk_status = 0;
1102 }
1103
1104 /*
1105  * 7.   Decode the RPC reply
1106  */
1107 static void
1108 call_decode(struct rpc_task *task)
1109 {
1110         struct rpc_clnt *clnt = task->tk_client;
1111         struct rpc_rqst *req = task->tk_rqstp;
1112         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1113         __be32          *p;
1114
1115         dprintk("RPC: %5u call_decode (status %d)\n",
1116                         task->tk_pid, task->tk_status);
1117
1118         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1119                 printk(KERN_NOTICE "%s: server %s OK\n",
1120                         clnt->cl_protname, clnt->cl_server);
1121                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1122         }
1123
1124         if (task->tk_status < 12) {
1125                 if (!RPC_IS_SOFT(task)) {
1126                         task->tk_action = call_bind;
1127                         clnt->cl_stats->rpcretrans++;
1128                         goto out_retry;
1129                 }
1130                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1131                                 clnt->cl_protname, task->tk_status);
1132                 task->tk_action = call_timeout;
1133                 goto out_retry;
1134         }
1135
1136         /*
1137          * Ensure that we see all writes made by xprt_complete_rqst()
1138          * before it changed req->rq_received.
1139          */
1140         smp_rmb();
1141         req->rq_rcv_buf.len = req->rq_private_buf.len;
1142
1143         /* Check that the softirq receive buffer is valid */
1144         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1145                                 sizeof(req->rq_rcv_buf)) != 0);
1146
1147         /* Verify the RPC header */
1148         p = call_verify(task);
1149         if (IS_ERR(p)) {
1150                 if (p == ERR_PTR(-EAGAIN))
1151                         goto out_retry;
1152                 return;
1153         }
1154
1155         task->tk_action = rpc_exit_task;
1156
1157         if (decode) {
1158                 lock_kernel();
1159                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1160                                                       task->tk_msg.rpc_resp);
1161                 unlock_kernel();
1162         }
1163         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1164                         task->tk_status);
1165         return;
1166 out_retry:
1167         req->rq_received = req->rq_private_buf.len = 0;
1168         task->tk_status = 0;
1169         if (task->tk_client->cl_discrtry)
1170                 xprt_disconnect(task->tk_xprt);
1171 }
1172
1173 /*
1174  * 8.   Refresh the credentials if rejected by the server
1175  */
1176 static void
1177 call_refresh(struct rpc_task *task)
1178 {
1179         dprint_status(task);
1180
1181         xprt_release(task);     /* Must do to obtain new XID */
1182         task->tk_action = call_refreshresult;
1183         task->tk_status = 0;
1184         task->tk_client->cl_stats->rpcauthrefresh++;
1185         rpcauth_refreshcred(task);
1186 }
1187
1188 /*
1189  * 8a.  Process the results of a credential refresh
1190  */
1191 static void
1192 call_refreshresult(struct rpc_task *task)
1193 {
1194         int status = task->tk_status;
1195
1196         dprint_status(task);
1197
1198         task->tk_status = 0;
1199         task->tk_action = call_reserve;
1200         if (status >= 0 && rpcauth_uptodatecred(task))
1201                 return;
1202         if (status == -EACCES) {
1203                 rpc_exit(task, -EACCES);
1204                 return;
1205         }
1206         task->tk_action = call_refresh;
1207         if (status != -ETIMEDOUT)
1208                 rpc_delay(task, 3*HZ);
1209         return;
1210 }
1211
1212 /*
1213  * Call header serialization
1214  */
1215 static __be32 *
1216 call_header(struct rpc_task *task)
1217 {
1218         struct rpc_clnt *clnt = task->tk_client;
1219         struct rpc_rqst *req = task->tk_rqstp;
1220         __be32          *p = req->rq_svec[0].iov_base;
1221
1222         /* FIXME: check buffer size? */
1223
1224         p = xprt_skip_transport_header(task->tk_xprt, p);
1225         *p++ = req->rq_xid;             /* XID */
1226         *p++ = htonl(RPC_CALL);         /* CALL */
1227         *p++ = htonl(RPC_VERSION);      /* RPC version */
1228         *p++ = htonl(clnt->cl_prog);    /* program number */
1229         *p++ = htonl(clnt->cl_vers);    /* program version */
1230         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1231         p = rpcauth_marshcred(task, p);
1232         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1233         return p;
1234 }
1235
1236 /*
1237  * Reply header verification
1238  */
1239 static __be32 *
1240 call_verify(struct rpc_task *task)
1241 {
1242         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1243         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1244         __be32  *p = iov->iov_base;
1245         u32 n;
1246         int error = -EACCES;
1247
1248         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1249                 /* RFC-1014 says that the representation of XDR data must be a
1250                  * multiple of four bytes
1251                  * - if it isn't pointer subtraction in the NFS client may give
1252                  *   undefined results
1253                  */
1254                 printk(KERN_WARNING
1255                        "call_verify: XDR representation not a multiple of"
1256                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1257                 goto out_eio;
1258         }
1259         if ((len -= 3) < 0)
1260                 goto out_overflow;
1261         p += 1; /* skip XID */
1262
1263         if ((n = ntohl(*p++)) != RPC_REPLY) {
1264                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1265                 goto out_garbage;
1266         }
1267         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1268                 if (--len < 0)
1269                         goto out_overflow;
1270                 switch ((n = ntohl(*p++))) {
1271                         case RPC_AUTH_ERROR:
1272                                 break;
1273                         case RPC_MISMATCH:
1274                                 dprintk("RPC: %5u %s: RPC call version "
1275                                                 "mismatch!\n",
1276                                                 task->tk_pid, __FUNCTION__);
1277                                 error = -EPROTONOSUPPORT;
1278                                 goto out_err;
1279                         default:
1280                                 dprintk("RPC: %5u %s: RPC call rejected, "
1281                                                 "unknown error: %x\n",
1282                                                 task->tk_pid, __FUNCTION__, n);
1283                                 goto out_eio;
1284                 }
1285                 if (--len < 0)
1286                         goto out_overflow;
1287                 switch ((n = ntohl(*p++))) {
1288                 case RPC_AUTH_REJECTEDCRED:
1289                 case RPC_AUTH_REJECTEDVERF:
1290                 case RPCSEC_GSS_CREDPROBLEM:
1291                 case RPCSEC_GSS_CTXPROBLEM:
1292                         if (!task->tk_cred_retry)
1293                                 break;
1294                         task->tk_cred_retry--;
1295                         dprintk("RPC: %5u %s: retry stale creds\n",
1296                                         task->tk_pid, __FUNCTION__);
1297                         rpcauth_invalcred(task);
1298                         task->tk_action = call_refresh;
1299                         goto out_retry;
1300                 case RPC_AUTH_BADCRED:
1301                 case RPC_AUTH_BADVERF:
1302                         /* possibly garbled cred/verf? */
1303                         if (!task->tk_garb_retry)
1304                                 break;
1305                         task->tk_garb_retry--;
1306                         dprintk("RPC: %5u %s: retry garbled creds\n",
1307                                         task->tk_pid, __FUNCTION__);
1308                         task->tk_action = call_bind;
1309                         goto out_retry;
1310                 case RPC_AUTH_TOOWEAK:
1311                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1312                                "authentication.\n", task->tk_client->cl_server);
1313                         break;
1314                 default:
1315                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1316                         error = -EIO;
1317                 }
1318                 dprintk("RPC: %5u %s: call rejected %d\n",
1319                                 task->tk_pid, __FUNCTION__, n);
1320                 goto out_err;
1321         }
1322         if (!(p = rpcauth_checkverf(task, p))) {
1323                 printk(KERN_WARNING "call_verify: auth check failed\n");
1324                 goto out_garbage;               /* bad verifier, retry */
1325         }
1326         len = p - (__be32 *)iov->iov_base - 1;
1327         if (len < 0)
1328                 goto out_overflow;
1329         switch ((n = ntohl(*p++))) {
1330         case RPC_SUCCESS:
1331                 return p;
1332         case RPC_PROG_UNAVAIL:
1333                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1334                                 task->tk_pid, __FUNCTION__,
1335                                 (unsigned int)task->tk_client->cl_prog,
1336                                 task->tk_client->cl_server);
1337                 error = -EPFNOSUPPORT;
1338                 goto out_err;
1339         case RPC_PROG_MISMATCH:
1340                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1341                                 "server %s\n", task->tk_pid, __FUNCTION__,
1342                                 (unsigned int)task->tk_client->cl_prog,
1343                                 (unsigned int)task->tk_client->cl_vers,
1344                                 task->tk_client->cl_server);
1345                 error = -EPROTONOSUPPORT;
1346                 goto out_err;
1347         case RPC_PROC_UNAVAIL:
1348                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1349                                 "version %u on server %s\n",
1350                                 task->tk_pid, __FUNCTION__,
1351                                 task->tk_msg.rpc_proc,
1352                                 task->tk_client->cl_prog,
1353                                 task->tk_client->cl_vers,
1354                                 task->tk_client->cl_server);
1355                 error = -EOPNOTSUPP;
1356                 goto out_err;
1357         case RPC_GARBAGE_ARGS:
1358                 dprintk("RPC: %5u %s: server saw garbage\n",
1359                                 task->tk_pid, __FUNCTION__);
1360                 break;                  /* retry */
1361         default:
1362                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1363                 /* Also retry */
1364         }
1365
1366 out_garbage:
1367         task->tk_client->cl_stats->rpcgarbage++;
1368         if (task->tk_garb_retry) {
1369                 task->tk_garb_retry--;
1370                 dprintk("RPC: %5u %s: retrying\n",
1371                                 task->tk_pid, __FUNCTION__);
1372                 task->tk_action = call_bind;
1373 out_retry:
1374                 return ERR_PTR(-EAGAIN);
1375         }
1376         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1377 out_eio:
1378         error = -EIO;
1379 out_err:
1380         rpc_exit(task, error);
1381         return ERR_PTR(error);
1382 out_overflow:
1383         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1384         goto out_garbage;
1385 }
1386
1387 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1388 {
1389         return 0;
1390 }
1391
1392 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1393 {
1394         return 0;
1395 }
1396
1397 static struct rpc_procinfo rpcproc_null = {
1398         .p_encode = rpcproc_encode_null,
1399         .p_decode = rpcproc_decode_null,
1400 };
1401
1402 int rpc_ping(struct rpc_clnt *clnt, int flags)
1403 {
1404         struct rpc_message msg = {
1405                 .rpc_proc = &rpcproc_null,
1406         };
1407         int err;
1408         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1409         err = rpc_call_sync(clnt, &msg, flags);
1410         put_rpccred(msg.rpc_cred);
1411         return err;
1412 }