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/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 = -EINVAL;
 115         if (!xprt)
 116                 goto out_no_xprt;
 117         if (vers >= program->nrvers || !(version = program->version[vers]))
 118                 goto out_err;
 119
 120         err = -ENOMEM;
 121         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 122         if (!clnt)
 123                 goto out_err;
 124         clnt->cl_parent = clnt;
 125
 126         clnt->cl_server = clnt->cl_inline_name;
 127         len = strlen(servname) + 1;
 128         if (len > sizeof(clnt->cl_inline_name)) {
 129                 char *buf = kmalloc(len, GFP_KERNEL);
 130                 if (buf != 0)
 131                         clnt->cl_server = buf;
 132                 else
 133                         len = sizeof(clnt->cl_inline_name);
 134         }
 135         strlcpy(clnt->cl_server, servname, len);
 136
 137         clnt->cl_xprt     = xprt;
 138         clnt->cl_procinfo = version->procs;
 139         clnt->cl_maxproc  = version->nrprocs;
 140         clnt->cl_protname = program->name;
 141         clnt->cl_prog     = program->number;
 142         clnt->cl_vers     = version->number;
 143         clnt->cl_stats    = program->stats;
 144         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 145         err = -ENOMEM;
 146         if (clnt->cl_metrics == NULL)
 147                 goto out_no_stats;
 148         clnt->cl_program  = program;
 149         INIT_LIST_HEAD(&clnt->cl_tasks);
 150         spin_lock_init(&clnt->cl_lock);
 151
 152         if (!xprt_bound(clnt->cl_xprt))
 153                 clnt->cl_autobind = 1;
 154
 155         clnt->cl_rtt = &clnt->cl_rtt_default;
 156         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 157
 158         kref_init(&clnt->cl_kref);
 159
 160         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 161         if (err < 0)
 162                 goto out_no_path;
 163
 164         auth = rpcauth_create(flavor, clnt);
 165         if (IS_ERR(auth)) {
 166                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 167                                 flavor);
 168                 err = PTR_ERR(auth);
 169                 goto out_no_auth;
 170         }
 171
 172         /* save the nodename */
 173         clnt->cl_nodelen = strlen(utsname()->nodename);
 174         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 175                 clnt->cl_nodelen = UNX_MAXNODENAME;
 176         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 177         rpc_register_client(clnt);
 178         return clnt;
 179
 180 out_no_auth:
 181         if (!IS_ERR(clnt->cl_dentry)) {
 182                 rpc_rmdir(clnt->cl_dentry);
 183                 rpc_put_mount();
 184         }
 185 out_no_path:
 186         rpc_free_iostats(clnt->cl_metrics);
 187 out_no_stats:
 188         if (clnt->cl_server != clnt->cl_inline_name)
 189                 kfree(clnt->cl_server);
 190         kfree(clnt);
 191 out_err:
 192         xprt_put(xprt);
 193 out_no_xprt:
 194         return ERR_PTR(err);
 195 }
 196
 197 /*
 198  * rpc_create - create an RPC client and transport with one call
 199  * @args: rpc_clnt create argument structure
 200  *
 201  * Creates and initializes an RPC transport and an RPC client.
 202  *
 203  * It can ping the server in order to determine if it is up, and to see if
 204  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 205  * this behavior so asynchronous tasks can also use rpc_create.
 206  */
 207 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 208 {
 209         struct rpc_xprt *xprt;
 210         struct rpc_clnt *clnt;
 211
 212         xprt = xprt_create_transport(args->protocol, args->address,
 213                                         args->addrsize, args->timeout);
 214         if (IS_ERR(xprt))
 215                 return (struct rpc_clnt *)xprt;
 216
 217         /*
 218          * By default, kernel RPC client connects from a reserved port.
 219          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 220          * but it is always enabled for rpciod, which handles the connect
 221          * operation.
 222          */
 223         xprt->resvport = 1;
 224         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 225                 xprt->resvport = 0;
 226
 227         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 228                         args->program->name, args->servername, xprt);
 229
 230         clnt = rpc_new_client(xprt, args->servername, args->program,
 231                                 args->version, args->authflavor);
 232         if (IS_ERR(clnt))
 233                 return clnt;
 234
 235         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 236                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 237                 if (err != 0) {
 238                         rpc_shutdown_client(clnt);
 239                         return ERR_PTR(err);
 240                 }
 241         }
 242
 243         clnt->cl_softrtry = 1;
 244         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 245                 clnt->cl_softrtry = 0;
 246
 247         if (args->flags & RPC_CLNT_CREATE_INTR)
 248                 clnt->cl_intr = 1;
 249         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 250                 clnt->cl_autobind = 1;
 251         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 252                 clnt->cl_discrtry = 1;
 253
 254         return clnt;
 255 }
 256 EXPORT_SYMBOL_GPL(rpc_create);
 257
 258 /*
 259  * This function clones the RPC client structure. It allows us to share the
 260  * same transport while varying parameters such as the authentication
 261  * flavour.
 262  */
 263 struct rpc_clnt *
 264 rpc_clone_client(struct rpc_clnt *clnt)
 265 {
 266         struct rpc_clnt *new;
 267         int err = -ENOMEM;
 268
 269         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 270         if (!new)
 271                 goto out_no_clnt;
 272         new->cl_metrics = rpc_alloc_iostats(clnt);
 273         if (new->cl_metrics == NULL)
 274                 goto out_no_stats;
 275         kref_init(&new->cl_kref);
 276         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 277         if (err != 0)
 278                 goto out_no_path;
 279         new->cl_parent = clnt;
 280         kref_get(&clnt->cl_kref);
 281         new->cl_xprt = xprt_get(clnt->cl_xprt);
 282         /* Turn off autobind on clones */
 283         new->cl_autobind = 0;
 284         INIT_LIST_HEAD(&new->cl_tasks);
 285         spin_lock_init(&new->cl_lock);
 286         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 287         if (new->cl_auth)
 288                 atomic_inc(&new->cl_auth->au_count);
 289         rpc_register_client(new);
 290         return new;
 291 out_no_path:
 292         rpc_free_iostats(new->cl_metrics);
 293 out_no_stats:
 294         kfree(new);
 295 out_no_clnt:
 296         dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
 297         return ERR_PTR(err);
 298 }
 299
 300 /*
 301  * Properly shut down an RPC client, terminating all outstanding
 302  * requests.
 303  */
 304 void rpc_shutdown_client(struct rpc_clnt *clnt)
 305 {
 306         dprintk("RPC:       shutting down %s client for %s\n",
 307                         clnt->cl_protname, clnt->cl_server);
 308
 309         while (!list_empty(&clnt->cl_tasks)) {
 310                 rpc_killall_tasks(clnt);
 311                 wait_event_timeout(destroy_wait,
 312                         list_empty(&clnt->cl_tasks), 1*HZ);
 313         }
 314
 315         rpc_release_client(clnt);
 316 }
 317
 318 /*
 319  * Free an RPC client
 320  */
 321 static void
 322 rpc_free_client(struct kref *kref)
 323 {
 324         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 325
 326         dprintk("RPC:       destroying %s client for %s\n",
 327                         clnt->cl_protname, clnt->cl_server);
 328         if (clnt->cl_auth) {
 329                 rpcauth_destroy(clnt->cl_auth);
 330                 clnt->cl_auth = NULL;
 331         }
 332         if (!IS_ERR(clnt->cl_dentry)) {
 333                 rpc_rmdir(clnt->cl_dentry);
 334                 rpc_put_mount();
 335         }
 336         if (clnt->cl_parent != clnt) {
 337                 rpc_release_client(clnt->cl_parent);
 338                 goto out_free;
 339         }
 340         if (clnt->cl_server != clnt->cl_inline_name)
 341                 kfree(clnt->cl_server);
 342 out_free:
 343         rpc_unregister_client(clnt);
 344         rpc_free_iostats(clnt->cl_metrics);
 345         clnt->cl_metrics = NULL;
 346         xprt_put(clnt->cl_xprt);
 347         kfree(clnt);
 348 }
 349
 350 /*
 351  * Release reference to the RPC client
 352  */
 353 void
 354 rpc_release_client(struct rpc_clnt *clnt)
 355 {
 356         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 357
 358         if (list_empty(&clnt->cl_tasks))
 359                 wake_up(&destroy_wait);
 360         kref_put(&clnt->cl_kref, rpc_free_client);
 361 }
 362
 363 /**
 364  * rpc_bind_new_program - bind a new RPC program to an existing client
 365  * @old - old rpc_client
 366  * @program - rpc program to set
 367  * @vers - rpc program version
 368  *
 369  * Clones the rpc client and sets up a new RPC program. This is mainly
 370  * of use for enabling different RPC programs to share the same transport.
 371  * The Sun NFSv2/v3 ACL protocol can do this.
 372  */
 373 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 374                                       struct rpc_program *program,
 375                                       int vers)
 376 {
 377         struct rpc_clnt *clnt;
 378         struct rpc_version *version;
 379         int err;
 380
 381         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 382         version = program->version[vers];
 383         clnt = rpc_clone_client(old);
 384         if (IS_ERR(clnt))
 385                 goto out;
 386         clnt->cl_procinfo = version->procs;
 387         clnt->cl_maxproc  = version->nrprocs;
 388         clnt->cl_protname = program->name;
 389         clnt->cl_prog     = program->number;
 390         clnt->cl_vers     = version->number;
 391         clnt->cl_stats    = program->stats;
 392         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 393         if (err != 0) {
 394                 rpc_shutdown_client(clnt);
 395                 clnt = ERR_PTR(err);
 396         }
 397 out:
 398         return clnt;
 399 }
 400
 401 /*
 402  * Default callback for async RPC calls
 403  */
 404 static void
 405 rpc_default_callback(struct rpc_task *task, void *data)
 406 {
 407 }
 408
 409 static const struct rpc_call_ops rpc_default_ops = {
 410         .rpc_call_done = rpc_default_callback,
 411 };
 412
 413 /*
 414  *      Export the signal mask handling for synchronous code that
 415  *      sleeps on RPC calls
 416  */
 417 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 418
 419 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 420 {
 421         unsigned long   sigallow = sigmask(SIGKILL);
 422         sigset_t sigmask;
 423
 424         /* Block all signals except those listed in sigallow */
 425         if (intr)
 426                 sigallow |= RPC_INTR_SIGNALS;
 427         siginitsetinv(&sigmask, sigallow);
 428         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 429 }
 430
 431 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 432 {
 433         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 434 }
 435
 436 static inline void rpc_restore_sigmask(sigset_t *oldset)
 437 {
 438         sigprocmask(SIG_SETMASK, oldset, NULL);
 439 }
 440
 441 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 442 {
 443         rpc_save_sigmask(oldset, clnt->cl_intr);
 444 }
 445
 446 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 447 {
 448         rpc_restore_sigmask(oldset);
 449 }
 450
 451 /*
 452  * New rpc_call implementation
 453  */
 454 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 455 {
 456         struct rpc_task *task;
 457         sigset_t        oldset;
 458         int             status;
 459
 460         BUG_ON(flags & RPC_TASK_ASYNC);
 461
 462         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 463         if (task == NULL)
 464                 return -ENOMEM;
 465
 466         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 467         rpc_task_sigmask(task, &oldset);
 468
 469         /* Set up the call info struct and execute the task */
 470         rpc_call_setup(task, msg, 0);
 471         if (task->tk_status == 0) {
 472                 atomic_inc(&task->tk_count);
 473                 rpc_execute(task);
 474         }
 475         status = task->tk_status;
 476         rpc_put_task(task);
 477         rpc_restore_sigmask(&oldset);
 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         flags |= RPC_TASK_ASYNC;
 493
 494         /* Create/initialize a new RPC task */
 495         status = -ENOMEM;
 496         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 497                 goto out_release;
 498
 499         /* Mask signals on GSS_AUTH upcalls */
 500         rpc_task_sigmask(task, &oldset);
 501
 502         rpc_call_setup(task, msg, 0);
 503
 504         /* Set up the call info struct and execute the task */
 505         status = task->tk_status;
 506         if (status == 0)
 507                 rpc_execute(task);
 508         else
 509                 rpc_put_task(task);
 510
 511         rpc_restore_sigmask(&oldset);
 512         return status;
 513 out_release:
 514         rpc_release_calldata(tk_ops, data);
 515         return status;
 516 }
 517
 518
 519 void
 520 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 521 {
 522         task->tk_msg   = *msg;
 523         task->tk_flags |= flags;
 524         /* Bind the user cred */
 525         if (task->tk_msg.rpc_cred != NULL)
 526                 rpcauth_holdcred(task);
 527         else
 528                 rpcauth_bindcred(task);
 529
 530         if (task->tk_status == 0)
 531                 task->tk_action = call_start;
 532         else
 533                 task->tk_action = rpc_exit_task;
 534 }
 535
 536 /**
 537  * rpc_peeraddr - extract remote peer address from clnt's xprt
 538  * @clnt: RPC client structure
 539  * @buf: target buffer
 540  * @size: length of target buffer
 541  *
 542  * Returns the number of bytes that are actually in the stored address.
 543  */
 544 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 545 {
 546         size_t bytes;
 547         struct rpc_xprt *xprt = clnt->cl_xprt;
 548
 549         bytes = sizeof(xprt->addr);
 550         if (bytes > bufsize)
 551                 bytes = bufsize;
 552         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 553         return xprt->addrlen;
 554 }
 555 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 556
 557 /**
 558  * rpc_peeraddr2str - return remote peer address in printable format
 559  * @clnt: RPC client structure
 560  * @format: address format
 561  *
 562  */
 563 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 564 {
 565         struct rpc_xprt *xprt = clnt->cl_xprt;
 566
 567         if (xprt->address_strings[format] != NULL)
 568                 return xprt->address_strings[format];
 569         else
 570                 return "unprintable";
 571 }
 572 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 573
 574 void
 575 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 576 {
 577         struct rpc_xprt *xprt = clnt->cl_xprt;
 578         if (xprt->ops->set_buffer_size)
 579                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 580 }
 581
 582 /*
 583  * Return size of largest payload RPC client can support, in bytes
 584  *
 585  * For stream transports, this is one RPC record fragment (see RFC
 586  * 1831), as we don't support multi-record requests yet.  For datagram
 587  * transports, this is the size of an IP packet minus the IP, UDP, and
 588  * RPC header sizes.
 589  */
 590 size_t rpc_max_payload(struct rpc_clnt *clnt)
 591 {
 592         return clnt->cl_xprt->max_payload;
 593 }
 594 EXPORT_SYMBOL_GPL(rpc_max_payload);
 595
 596 /**
 597  * rpc_force_rebind - force transport to check that remote port is unchanged
 598  * @clnt: client to rebind
 599  *
 600  */
 601 void rpc_force_rebind(struct rpc_clnt *clnt)
 602 {
 603         if (clnt->cl_autobind)
 604                 xprt_clear_bound(clnt->cl_xprt);
 605 }
 606 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 607
 608 /*
 609  * Restart an (async) RPC call. Usually called from within the
 610  * exit handler.
 611  */
 612 void
 613 rpc_restart_call(struct rpc_task *task)
 614 {
 615         if (RPC_ASSASSINATED(task))
 616                 return;
 617
 618         task->tk_action = call_start;
 619 }
 620
 621 /*
 622  * 0.  Initial state
 623  *
 624  *     Other FSM states can be visited zero or more times, but
 625  *     this state is visited exactly once for each RPC.
 626  */
 627 static void
 628 call_start(struct rpc_task *task)
 629 {
 630         struct rpc_clnt *clnt = task->tk_client;
 631
 632         dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
 633                         clnt->cl_protname, clnt->cl_vers,
 634                         task->tk_msg.rpc_proc->p_proc,
 635                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 636
 637         /* Increment call count */
 638         task->tk_msg.rpc_proc->p_count++;
 639         clnt->cl_stats->rpccnt++;
 640         task->tk_action = call_reserve;
 641 }
 642
 643 /*
 644  * 1.   Reserve an RPC call slot
 645  */
 646 static void
 647 call_reserve(struct rpc_task *task)
 648 {
 649         dprint_status(task);
 650
 651         if (!rpcauth_uptodatecred(task)) {
 652                 task->tk_action = call_refresh;
 653                 return;
 654         }
 655
 656         task->tk_status  = 0;
 657         task->tk_action  = call_reserveresult;
 658         xprt_reserve(task);
 659 }
 660
 661 /*
 662  * 1b.  Grok the result of xprt_reserve()
 663  */
 664 static void
 665 call_reserveresult(struct rpc_task *task)
 666 {
 667         int status = task->tk_status;
 668
 669         dprint_status(task);
 670
 671         /*
 672          * After a call to xprt_reserve(), we must have either
 673          * a request slot or else an error status.
 674          */
 675         task->tk_status = 0;
 676         if (status >= 0) {
 677                 if (task->tk_rqstp) {
 678                         task->tk_action = call_allocate;
 679                         return;
 680                 }
 681
 682                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 683                                 __FUNCTION__, status);
 684                 rpc_exit(task, -EIO);
 685                 return;
 686         }
 687
 688         /*
 689          * Even though there was an error, we may have acquired
 690          * a request slot somehow.  Make sure not to leak it.
 691          */
 692         if (task->tk_rqstp) {
 693                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 694                                 __FUNCTION__, status);
 695                 xprt_release(task);
 696         }
 697
 698         switch (status) {
 699         case -EAGAIN:   /* woken up; retry */
 700                 task->tk_action = call_reserve;
 701                 return;
 702         case -EIO:      /* probably a shutdown */
 703                 break;
 704         default:
 705                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 706                                 __FUNCTION__, status);
 707                 break;
 708         }
 709         rpc_exit(task, status);
 710 }
 711
 712 /*
 713  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 714  *      (Note: buffer memory is freed in xprt_release).
 715  */
 716 static void
 717 call_allocate(struct rpc_task *task)
 718 {
 719         unsigned int slack = task->tk_auth->au_cslack;
 720         struct rpc_rqst *req = task->tk_rqstp;
 721         struct rpc_xprt *xprt = task->tk_xprt;
 722         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 723
 724         dprint_status(task);
 725
 726         task->tk_status = 0;
 727         task->tk_action = call_bind;
 728
 729         if (req->rq_buffer)
 730                 return;
 731
 732         if (proc->p_proc != 0) {
 733                 BUG_ON(proc->p_arglen == 0);
 734                 if (proc->p_decode != NULL)
 735                         BUG_ON(proc->p_replen == 0);
 736         }
 737
 738         /*
 739          * Calculate the size (in quads) of the RPC call
 740          * and reply headers, and convert both values
 741          * to byte sizes.
 742          */
 743         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
 744         req->rq_callsize <<= 2;
 745         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
 746         req->rq_rcvsize <<= 2;
 747
 748         req->rq_buffer = xprt->ops->buf_alloc(task,
 749                                         req->rq_callsize + req->rq_rcvsize);
 750         if (req->rq_buffer != NULL)
 751                 return;
 752
 753         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
 754
 755         if (RPC_IS_ASYNC(task) || !signalled()) {
 756                 xprt_release(task);
 757                 task->tk_action = call_reserve;
 758                 rpc_delay(task, HZ>>4);
 759                 return;
 760         }
 761
 762         rpc_exit(task, -ERESTARTSYS);
 763 }
 764
 765 static inline int
 766 rpc_task_need_encode(struct rpc_task *task)
 767 {
 768         return task->tk_rqstp->rq_snd_buf.len == 0;
 769 }
 770
 771 static inline void
 772 rpc_task_force_reencode(struct rpc_task *task)
 773 {
 774         task->tk_rqstp->rq_snd_buf.len = 0;
 775 }
 776
 777 static inline void
 778 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
 779 {
 780         buf->head[0].iov_base = start;
 781         buf->head[0].iov_len = len;
 782         buf->tail[0].iov_len = 0;
 783         buf->page_len = 0;
 784         buf->len = 0;
 785         buf->buflen = len;
 786 }
 787
 788 /*
 789  * 3.   Encode arguments of an RPC call
 790  */
 791 static void
 792 call_encode(struct rpc_task *task)
 793 {
 794         struct rpc_rqst *req = task->tk_rqstp;
 795         kxdrproc_t      encode;
 796         __be32          *p;
 797
 798         dprint_status(task);
 799
 800         rpc_xdr_buf_init(&req->rq_snd_buf,
 801                          req->rq_buffer,
 802                          req->rq_callsize);
 803         rpc_xdr_buf_init(&req->rq_rcv_buf,
 804                          (char *)req->rq_buffer + req->rq_callsize,
 805                          req->rq_rcvsize);
 806
 807         /* Encode header and provided arguments */
 808         encode = task->tk_msg.rpc_proc->p_encode;
 809         if (!(p = call_header(task))) {
 810                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 811                 rpc_exit(task, -EIO);
 812                 return;
 813         }
 814         if (encode == NULL)
 815                 return;
 816
 817         lock_kernel();
 818         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 819                         task->tk_msg.rpc_argp);
 820         unlock_kernel();
 821         if (task->tk_status == -ENOMEM) {
 822                 /* XXX: Is this sane? */
 823                 rpc_delay(task, 3*HZ);
 824                 task->tk_status = -EAGAIN;
 825         }
 826 }
 827
 828 /*
 829  * 4.   Get the server port number if not yet set
 830  */
 831 static void
 832 call_bind(struct rpc_task *task)
 833 {
 834         struct rpc_xprt *xprt = task->tk_xprt;
 835
 836         dprint_status(task);
 837
 838         task->tk_action = call_connect;
 839         if (!xprt_bound(xprt)) {
 840                 task->tk_action = call_bind_status;
 841                 task->tk_timeout = xprt->bind_timeout;
 842                 xprt->ops->rpcbind(task);
 843         }
 844 }
 845
 846 /*
 847  * 4a.  Sort out bind result
 848  */
 849 static void
 850 call_bind_status(struct rpc_task *task)
 851 {
 852         int status = -EACCES;
 853
 854         if (task->tk_status >= 0) {
 855                 dprint_status(task);
 856                 task->tk_status = 0;
 857                 task->tk_action = call_connect;
 858                 return;
 859         }
 860
 861         switch (task->tk_status) {
 862         case -EACCES:
 863                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
 864                                 "unavailable\n", task->tk_pid);
 865                 rpc_delay(task, 3*HZ);
 866                 goto retry_timeout;
 867         case -ETIMEDOUT:
 868                 dprintk("RPC: %5u rpcbind request timed out\n",
 869                                 task->tk_pid);
 870                 goto retry_timeout;
 871         case -EPFNOSUPPORT:
 872                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
 873                                 task->tk_pid);
 874                 break;
 875         case -EPROTONOSUPPORT:
 876                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
 877                                 task->tk_pid);
 878                 task->tk_status = 0;
 879                 task->tk_action = call_bind;
 880                 return;
 881         default:
 882                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 883                                 task->tk_pid, -task->tk_status);
 884                 status = -EIO;
 885         }
 886
 887         rpc_exit(task, status);
 888         return;
 889
 890 retry_timeout:
 891         task->tk_action = call_timeout;
 892 }
 893
 894 /*
 895  * 4b.  Connect to the RPC server
 896  */
 897 static void
 898 call_connect(struct rpc_task *task)
 899 {
 900         struct rpc_xprt *xprt = task->tk_xprt;
 901
 902         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
 903                         task->tk_pid, xprt,
 904                         (xprt_connected(xprt) ? "is" : "is not"));
 905
 906         task->tk_action = call_transmit;
 907         if (!xprt_connected(xprt)) {
 908                 task->tk_action = call_connect_status;
 909                 if (task->tk_status < 0)
 910                         return;
 911                 xprt_connect(task);
 912         }
 913 }
 914
 915 /*
 916  * 4c.  Sort out connect result
 917  */
 918 static void
 919 call_connect_status(struct rpc_task *task)
 920 {
 921         struct rpc_clnt *clnt = task->tk_client;
 922         int status = task->tk_status;
 923
 924         dprint_status(task);
 925
 926         task->tk_status = 0;
 927         if (status >= 0) {
 928                 clnt->cl_stats->netreconn++;
 929                 task->tk_action = call_transmit;
 930                 return;
 931         }
 932
 933         /* Something failed: remote service port may have changed */
 934         rpc_force_rebind(clnt);
 935
 936         switch (status) {
 937         case -ENOTCONN:
 938         case -EAGAIN:
 939                 task->tk_action = call_bind;
 940                 if (!RPC_IS_SOFT(task))
 941                         return;
 942                 /* if soft mounted, test if we've timed out */
 943         case -ETIMEDOUT:
 944                 task->tk_action = call_timeout;
 945                 return;
 946         }
 947         rpc_exit(task, -EIO);
 948 }
 949
 950 /*
 951  * 5.   Transmit the RPC request, and wait for reply
 952  */
 953 static void
 954 call_transmit(struct rpc_task *task)
 955 {
 956         dprint_status(task);
 957
 958         task->tk_action = call_status;
 959         if (task->tk_status < 0)
 960                 return;
 961         task->tk_status = xprt_prepare_transmit(task);
 962         if (task->tk_status != 0)
 963                 return;
 964         task->tk_action = call_transmit_status;
 965         /* Encode here so that rpcsec_gss can use correct sequence number. */
 966         if (rpc_task_need_encode(task)) {
 967                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 968                 call_encode(task);
 969                 /* Did the encode result in an error condition? */
 970                 if (task->tk_status != 0)
 971                         return;
 972         }
 973         xprt_transmit(task);
 974         if (task->tk_status < 0)
 975                 return;
 976         /*
 977          * On success, ensure that we call xprt_end_transmit() before sleeping
 978          * in order to allow access to the socket to other RPC requests.
 979          */
 980         call_transmit_status(task);
 981         if (task->tk_msg.rpc_proc->p_decode != NULL)
 982                 return;
 983         task->tk_action = rpc_exit_task;
 984         rpc_wake_up_task(task);
 985 }
 986
 987 /*
 988  * 5a.  Handle cleanup after a transmission
 989  */
 990 static void
 991 call_transmit_status(struct rpc_task *task)
 992 {
 993         task->tk_action = call_status;
 994         /*
 995          * Special case: if we've been waiting on the socket's write_space()
 996          * callback, then don't call xprt_end_transmit().
 997          */
 998         if (task->tk_status == -EAGAIN)
 999                 return;
1000         xprt_end_transmit(task);
1001         rpc_task_force_reencode(task);
1002 }
1003
1004 /*
1005  * 6.   Sort out the RPC call status
1006  */
1007 static void
1008 call_status(struct rpc_task *task)
1009 {
1010         struct rpc_clnt *clnt = task->tk_client;
1011         struct rpc_rqst *req = task->tk_rqstp;
1012         int             status;
1013
1014         if (req->rq_received > 0 && !req->rq_bytes_sent)
1015                 task->tk_status = req->rq_received;
1016
1017         dprint_status(task);
1018
1019         status = task->tk_status;
1020         if (status >= 0) {
1021                 task->tk_action = call_decode;
1022                 return;
1023         }
1024
1025         task->tk_status = 0;
1026         switch(status) {
1027         case -EHOSTDOWN:
1028         case -EHOSTUNREACH:
1029         case -ENETUNREACH:
1030                 /*
1031                  * Delay any retries for 3 seconds, then handle as if it
1032                  * were a timeout.
1033                  */
1034                 rpc_delay(task, 3*HZ);
1035         case -ETIMEDOUT:
1036                 task->tk_action = call_timeout;
1037                 if (task->tk_client->cl_discrtry)
1038                         xprt_disconnect(task->tk_xprt);
1039                 break;
1040         case -ECONNREFUSED:
1041         case -ENOTCONN:
1042                 rpc_force_rebind(clnt);
1043                 task->tk_action = call_bind;
1044                 break;
1045         case -EAGAIN:
1046                 task->tk_action = call_transmit;
1047                 break;
1048         case -EIO:
1049                 /* shutdown or soft timeout */
1050                 rpc_exit(task, status);
1051                 break;
1052         default:
1053                 printk("%s: RPC call returned error %d\n",
1054                                clnt->cl_protname, -status);
1055                 rpc_exit(task, status);
1056         }
1057 }
1058
1059 /*
1060  * 6a.  Handle RPC timeout
1061  *      We do not release the request slot, so we keep using the
1062  *      same XID for all retransmits.
1063  */
1064 static void
1065 call_timeout(struct rpc_task *task)
1066 {
1067         struct rpc_clnt *clnt = task->tk_client;
1068
1069         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1070                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1071                 goto retry;
1072         }
1073
1074         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1075         task->tk_timeouts++;
1076
1077         if (RPC_IS_SOFT(task)) {
1078                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1079                                 clnt->cl_protname, clnt->cl_server);
1080                 rpc_exit(task, -EIO);
1081                 return;
1082         }
1083
1084         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1085                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1086                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1087                         clnt->cl_protname, clnt->cl_server);
1088         }
1089         rpc_force_rebind(clnt);
1090
1091 retry:
1092         clnt->cl_stats->rpcretrans++;
1093         task->tk_action = call_bind;
1094         task->tk_status = 0;
1095 }
1096
1097 /*
1098  * 7.   Decode the RPC reply
1099  */
1100 static void
1101 call_decode(struct rpc_task *task)
1102 {
1103         struct rpc_clnt *clnt = task->tk_client;
1104         struct rpc_rqst *req = task->tk_rqstp;
1105         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1106         __be32          *p;
1107
1108         dprintk("RPC: %5u call_decode (status %d)\n",
1109                         task->tk_pid, task->tk_status);
1110
1111         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1112                 printk(KERN_NOTICE "%s: server %s OK\n",
1113                         clnt->cl_protname, clnt->cl_server);
1114                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1115         }
1116
1117         if (task->tk_status < 12) {
1118                 if (!RPC_IS_SOFT(task)) {
1119                         task->tk_action = call_bind;
1120                         clnt->cl_stats->rpcretrans++;
1121                         goto out_retry;
1122                 }
1123                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1124                                 clnt->cl_protname, task->tk_status);
1125                 task->tk_action = call_timeout;
1126                 goto out_retry;
1127         }
1128
1129         /*
1130          * Ensure that we see all writes made by xprt_complete_rqst()
1131          * before it changed req->rq_received.
1132          */
1133         smp_rmb();
1134         req->rq_rcv_buf.len = req->rq_private_buf.len;
1135
1136         /* Check that the softirq receive buffer is valid */
1137         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1138                                 sizeof(req->rq_rcv_buf)) != 0);
1139
1140         /* Verify the RPC header */
1141         p = call_verify(task);
1142         if (IS_ERR(p)) {
1143                 if (p == ERR_PTR(-EAGAIN))
1144                         goto out_retry;
1145                 return;
1146         }
1147
1148         task->tk_action = rpc_exit_task;
1149
1150         if (decode) {
1151                 lock_kernel();
1152                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1153                                                       task->tk_msg.rpc_resp);
1154                 unlock_kernel();
1155         }
1156         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1157                         task->tk_status);
1158         return;
1159 out_retry:
1160         req->rq_received = req->rq_private_buf.len = 0;
1161         task->tk_status = 0;
1162         if (task->tk_client->cl_discrtry)
1163                 xprt_disconnect(task->tk_xprt);
1164 }
1165
1166 /*
1167  * 8.   Refresh the credentials if rejected by the server
1168  */
1169 static void
1170 call_refresh(struct rpc_task *task)
1171 {
1172         dprint_status(task);
1173
1174         xprt_release(task);     /* Must do to obtain new XID */
1175         task->tk_action = call_refreshresult;
1176         task->tk_status = 0;
1177         task->tk_client->cl_stats->rpcauthrefresh++;
1178         rpcauth_refreshcred(task);
1179 }
1180
1181 /*
1182  * 8a.  Process the results of a credential refresh
1183  */
1184 static void
1185 call_refreshresult(struct rpc_task *task)
1186 {
1187         int status = task->tk_status;
1188
1189         dprint_status(task);
1190
1191         task->tk_status = 0;
1192         task->tk_action = call_reserve;
1193         if (status >= 0 && rpcauth_uptodatecred(task))
1194                 return;
1195         if (status == -EACCES) {
1196                 rpc_exit(task, -EACCES);
1197                 return;
1198         }
1199         task->tk_action = call_refresh;
1200         if (status != -ETIMEDOUT)
1201                 rpc_delay(task, 3*HZ);
1202         return;
1203 }
1204
1205 /*
1206  * Call header serialization
1207  */
1208 static __be32 *
1209 call_header(struct rpc_task *task)
1210 {
1211         struct rpc_clnt *clnt = task->tk_client;
1212         struct rpc_rqst *req = task->tk_rqstp;
1213         __be32          *p = req->rq_svec[0].iov_base;
1214
1215         /* FIXME: check buffer size? */
1216
1217         p = xprt_skip_transport_header(task->tk_xprt, p);
1218         *p++ = req->rq_xid;             /* XID */
1219         *p++ = htonl(RPC_CALL);         /* CALL */
1220         *p++ = htonl(RPC_VERSION);      /* RPC version */
1221         *p++ = htonl(clnt->cl_prog);    /* program number */
1222         *p++ = htonl(clnt->cl_vers);    /* program version */
1223         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1224         p = rpcauth_marshcred(task, p);
1225         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1226         return p;
1227 }
1228
1229 /*
1230  * Reply header verification
1231  */
1232 static __be32 *
1233 call_verify(struct rpc_task *task)
1234 {
1235         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1236         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1237         __be32  *p = iov->iov_base;
1238         u32 n;
1239         int error = -EACCES;
1240
1241         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1242                 /* RFC-1014 says that the representation of XDR data must be a
1243                  * multiple of four bytes
1244                  * - if it isn't pointer subtraction in the NFS client may give
1245                  *   undefined results
1246                  */
1247                 printk(KERN_WARNING
1248                        "call_verify: XDR representation not a multiple of"
1249                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1250                 goto out_eio;
1251         }
1252         if ((len -= 3) < 0)
1253                 goto out_overflow;
1254         p += 1; /* skip XID */
1255
1256         if ((n = ntohl(*p++)) != RPC_REPLY) {
1257                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1258                 goto out_garbage;
1259         }
1260         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1261                 if (--len < 0)
1262                         goto out_overflow;
1263                 switch ((n = ntohl(*p++))) {
1264                         case RPC_AUTH_ERROR:
1265                                 break;
1266                         case RPC_MISMATCH:
1267                                 dprintk("RPC: %5u %s: RPC call version "
1268                                                 "mismatch!\n",
1269                                                 task->tk_pid, __FUNCTION__);
1270                                 error = -EPROTONOSUPPORT;
1271                                 goto out_err;
1272                         default:
1273                                 dprintk("RPC: %5u %s: RPC call rejected, "
1274                                                 "unknown error: %x\n",
1275                                                 task->tk_pid, __FUNCTION__, n);
1276                                 goto out_eio;
1277                 }
1278                 if (--len < 0)
1279                         goto out_overflow;
1280                 switch ((n = ntohl(*p++))) {
1281                 case RPC_AUTH_REJECTEDCRED:
1282                 case RPC_AUTH_REJECTEDVERF:
1283                 case RPCSEC_GSS_CREDPROBLEM:
1284                 case RPCSEC_GSS_CTXPROBLEM:
1285                         if (!task->tk_cred_retry)
1286                                 break;
1287                         task->tk_cred_retry--;
1288                         dprintk("RPC: %5u %s: retry stale creds\n",
1289                                         task->tk_pid, __FUNCTION__);
1290                         rpcauth_invalcred(task);
1291                         task->tk_action = call_refresh;
1292                         goto out_retry;
1293                 case RPC_AUTH_BADCRED:
1294                 case RPC_AUTH_BADVERF:
1295                         /* possibly garbled cred/verf? */
1296                         if (!task->tk_garb_retry)
1297                                 break;
1298                         task->tk_garb_retry--;
1299                         dprintk("RPC: %5u %s: retry garbled creds\n",
1300                                         task->tk_pid, __FUNCTION__);
1301                         task->tk_action = call_bind;
1302                         goto out_retry;
1303                 case RPC_AUTH_TOOWEAK:
1304                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1305                                "authentication.\n", task->tk_client->cl_server);
1306                         break;
1307                 default:
1308                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1309                         error = -EIO;
1310                 }
1311                 dprintk("RPC: %5u %s: call rejected %d\n",
1312                                 task->tk_pid, __FUNCTION__, n);
1313                 goto out_err;
1314         }
1315         if (!(p = rpcauth_checkverf(task, p))) {
1316                 printk(KERN_WARNING "call_verify: auth check failed\n");
1317                 goto out_garbage;               /* bad verifier, retry */
1318         }
1319         len = p - (__be32 *)iov->iov_base - 1;
1320         if (len < 0)
1321                 goto out_overflow;
1322         switch ((n = ntohl(*p++))) {
1323         case RPC_SUCCESS:
1324                 return p;
1325         case RPC_PROG_UNAVAIL:
1326                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1327                                 task->tk_pid, __FUNCTION__,
1328                                 (unsigned int)task->tk_client->cl_prog,
1329                                 task->tk_client->cl_server);
1330                 error = -EPFNOSUPPORT;
1331                 goto out_err;
1332         case RPC_PROG_MISMATCH:
1333                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1334                                 "server %s\n", task->tk_pid, __FUNCTION__,
1335                                 (unsigned int)task->tk_client->cl_prog,
1336                                 (unsigned int)task->tk_client->cl_vers,
1337                                 task->tk_client->cl_server);
1338                 error = -EPROTONOSUPPORT;
1339                 goto out_err;
1340         case RPC_PROC_UNAVAIL:
1341                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1342                                 "version %u on server %s\n",
1343                                 task->tk_pid, __FUNCTION__,
1344                                 task->tk_msg.rpc_proc,
1345                                 task->tk_client->cl_prog,
1346                                 task->tk_client->cl_vers,
1347                                 task->tk_client->cl_server);
1348                 error = -EOPNOTSUPP;
1349                 goto out_err;
1350         case RPC_GARBAGE_ARGS:
1351                 dprintk("RPC: %5u %s: server saw garbage\n",
1352                                 task->tk_pid, __FUNCTION__);
1353                 break;                  /* retry */
1354         default:
1355                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1356                 /* Also retry */
1357         }
1358
1359 out_garbage:
1360         task->tk_client->cl_stats->rpcgarbage++;
1361         if (task->tk_garb_retry) {
1362                 task->tk_garb_retry--;
1363                 dprintk("RPC: %5u %s: retrying\n",
1364                                 task->tk_pid, __FUNCTION__);
1365                 task->tk_action = call_bind;
1366 out_retry:
1367                 return ERR_PTR(-EAGAIN);
1368         }
1369         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1370 out_eio:
1371         error = -EIO;
1372 out_err:
1373         rpc_exit(task, error);
1374         return ERR_PTR(error);
1375 out_overflow:
1376         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1377         goto out_garbage;
1378 }
1379
1380 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1381 {
1382         return 0;
1383 }
1384
1385 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1386 {
1387         return 0;
1388 }
1389
1390 static struct rpc_procinfo rpcproc_null = {
1391         .p_encode = rpcproc_encode_null,
1392         .p_decode = rpcproc_decode_null,
1393 };
1394
1395 int rpc_ping(struct rpc_clnt *clnt, int flags)
1396 {
1397         struct rpc_message msg = {
1398                 .rpc_proc = &rpcproc_null,
1399         };
1400         int err;
1401         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1402         err = rpc_call_sync(clnt, &msg, flags);
1403         put_rpccred(msg.rpc_cred);
1404         return err;
1405 }