git.oblomov.eu Git - linux-2.6/blob - net/sunrpc/clnt.c

   1 /*
   2  *  linux/net/sunrpc/clnt.c
   3  *
   4  *  This file contains the high-level RPC interface.
   5  *  It is modeled as a finite state machine to support both synchronous
   6  *  and asynchronous requests.
   7  *
   8  *  -   RPC header generation and argument serialization.
   9  *  -   Credential refresh.
  10  *  -   TCP connect handling.
  11  *  -   Retry of operation when it is suspected the operation failed because
  12  *      of uid squashing on the server, or when the credentials were stale
  13  *      and need to be refreshed, or when a packet was damaged in transit.
  14  *      This may be have to be moved to the VFS layer.
  15  *
  16  *  NB: BSD uses a more intelligent approach to guessing when a request
  17  *  or reply has been lost by keeping the RTO estimate for each procedure.
  18  *  We currently make do with a constant timeout value.
  19  *
  20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  22  */
  23
  24 #include <asm/system.h>
  25
  26 #include <linux/module.h>
  27 #include <linux/types.h>
  28 #include <linux/mm.h>
  29 #include <linux/slab.h>
  30 #include <linux/utsname.h>
  31 #include <linux/workqueue.h>
  32
  33 #include <linux/sunrpc/clnt.h>
  34 #include <linux/sunrpc/rpc_pipe_fs.h>
  35 #include <linux/sunrpc/metrics.h>
  36
  37
  38 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
  39
  40 #ifdef RPC_DEBUG
  41 # define RPCDBG_FACILITY        RPCDBG_CALL
  42 #endif
  43
  44 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  45
  46
  47 static void     call_start(struct rpc_task *task);
  48 static void     call_reserve(struct rpc_task *task);
  49 static void     call_reserveresult(struct rpc_task *task);
  50 static void     call_allocate(struct rpc_task *task);
  51 static void     call_encode(struct rpc_task *task);
  52 static void     call_decode(struct rpc_task *task);
  53 static void     call_bind(struct rpc_task *task);
  54 static void     call_bind_status(struct rpc_task *task);
  55 static void     call_transmit(struct rpc_task *task);
  56 static void     call_status(struct rpc_task *task);
  57 static void     call_transmit_status(struct rpc_task *task);
  58 static void     call_refresh(struct rpc_task *task);
  59 static void     call_refreshresult(struct rpc_task *task);
  60 static void     call_timeout(struct rpc_task *task);
  61 static void     call_connect(struct rpc_task *task);
  62 static void     call_connect_status(struct rpc_task *task);
  63 static u32 *    call_header(struct rpc_task *task);
  64 static u32 *    call_verify(struct rpc_task *task);
  65
  66
  67 static int
  68 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  69 {
  70         static uint32_t clntid;
  71         int error;
  72
  73         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  74         clnt->cl_dentry = ERR_PTR(-ENOENT);
  75         if (dir_name == NULL)
  76                 return 0;
  77
  78         clnt->cl_vfsmnt = rpc_get_mount();
  79         if (IS_ERR(clnt->cl_vfsmnt))
  80                 return PTR_ERR(clnt->cl_vfsmnt);
  81
  82         for (;;) {
  83                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  84                                 "%s/clnt%x", dir_name,
  85                                 (unsigned int)clntid++);
  86                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  87                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  88                 if (!IS_ERR(clnt->cl_dentry))
  89                         return 0;
  90                 error = PTR_ERR(clnt->cl_dentry);
  91                 if (error != -EEXIST) {
  92                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  93                                         clnt->cl_pathname, error);
  94                         rpc_put_mount();
  95                         return error;
  96                 }
  97         }
  98 }
  99
 100 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
 101 {
 102         struct rpc_version      *version;
 103         struct rpc_clnt         *clnt = NULL;
 104         struct rpc_auth         *auth;
 105         int err;
 106         int len;
 107
 108         dprintk("RPC: creating %s client for %s (xprt %p)\n",
 109                 program->name, servname, xprt);
 110
 111         err = -EINVAL;
 112         if (!xprt)
 113                 goto out_no_xprt;
 114         if (vers >= program->nrvers || !(version = program->version[vers]))
 115                 goto out_err;
 116
 117         err = -ENOMEM;
 118         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 119         if (!clnt)
 120                 goto out_err;
 121         atomic_set(&clnt->cl_users, 0);
 122         atomic_set(&clnt->cl_count, 1);
 123         clnt->cl_parent = clnt;
 124
 125         clnt->cl_server = clnt->cl_inline_name;
 126         len = strlen(servname) + 1;
 127         if (len > sizeof(clnt->cl_inline_name)) {
 128                 char *buf = kmalloc(len, GFP_KERNEL);
 129                 if (buf != 0)
 130                         clnt->cl_server = buf;
 131                 else
 132                         len = sizeof(clnt->cl_inline_name);
 133         }
 134         strlcpy(clnt->cl_server, servname, len);
 135
 136         clnt->cl_xprt     = xprt;
 137         clnt->cl_procinfo = version->procs;
 138         clnt->cl_maxproc  = version->nrprocs;
 139         clnt->cl_protname = program->name;
 140         clnt->cl_prog     = program->number;
 141         clnt->cl_vers     = version->number;
 142         clnt->cl_stats    = program->stats;
 143         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 144
 145         if (!xprt_bound(clnt->cl_xprt))
 146                 clnt->cl_autobind = 1;
 147
 148         clnt->cl_rtt = &clnt->cl_rtt_default;
 149         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 150
 151         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 152         if (err < 0)
 153                 goto out_no_path;
 154
 155         auth = rpcauth_create(flavor, clnt);
 156         if (IS_ERR(auth)) {
 157                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 158                                 flavor);
 159                 err = PTR_ERR(auth);
 160                 goto out_no_auth;
 161         }
 162
 163         /* save the nodename */
 164         clnt->cl_nodelen = strlen(system_utsname.nodename);
 165         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 166                 clnt->cl_nodelen = UNX_MAXNODENAME;
 167         memcpy(clnt->cl_nodename, system_utsname.nodename, clnt->cl_nodelen);
 168         return clnt;
 169
 170 out_no_auth:
 171         if (!IS_ERR(clnt->cl_dentry)) {
 172                 rpc_rmdir(clnt->cl_dentry);
 173                 rpc_put_mount();
 174         }
 175 out_no_path:
 176         if (clnt->cl_server != clnt->cl_inline_name)
 177                 kfree(clnt->cl_server);
 178         kfree(clnt);
 179 out_err:
 180         xprt_destroy(xprt);
 181 out_no_xprt:
 182         return ERR_PTR(err);
 183 }
 184
 185 /*
 186  * rpc_create - create an RPC client and transport with one call
 187  * @args: rpc_clnt create argument structure
 188  *
 189  * Creates and initializes an RPC transport and an RPC client.
 190  *
 191  * It can ping the server in order to determine if it is up, and to see if
 192  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 193  * this behavior so asynchronous tasks can also use rpc_create.
 194  */
 195 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 196 {
 197         struct rpc_xprt *xprt;
 198         struct rpc_clnt *clnt;
 199
 200         xprt = xprt_create_transport(args->protocol, args->address,
 201                                         args->addrsize, args->timeout);
 202         if (IS_ERR(xprt))
 203                 return (struct rpc_clnt *)xprt;
 204
 205         /*
 206          * By default, kernel RPC client connects from a reserved port.
 207          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 208          * but it is always enabled for rpciod, which handles the connect
 209          * operation.
 210          */
 211         xprt->resvport = 1;
 212         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 213                 xprt->resvport = 0;
 214
 215         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 216                 args->program->name, args->servername, xprt);
 217
 218         clnt = rpc_new_client(xprt, args->servername, args->program,
 219                                 args->version, args->authflavor);
 220         if (IS_ERR(clnt))
 221                 return clnt;
 222
 223         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 224                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 225                 if (err != 0) {
 226                         rpc_shutdown_client(clnt);
 227                         return ERR_PTR(err);
 228                 }
 229         }
 230
 231         clnt->cl_softrtry = 1;
 232         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 233                 clnt->cl_softrtry = 0;
 234
 235         if (args->flags & RPC_CLNT_CREATE_INTR)
 236                 clnt->cl_intr = 1;
 237         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 238                 clnt->cl_autobind = 1;
 239         if (args->flags & RPC_CLNT_CREATE_ONESHOT)
 240                 clnt->cl_oneshot = 1;
 241
 242         return clnt;
 243 }
 244 EXPORT_SYMBOL_GPL(rpc_create);
 245
 246 /*
 247  * This function clones the RPC client structure. It allows us to share the
 248  * same transport while varying parameters such as the authentication
 249  * flavour.
 250  */
 251 struct rpc_clnt *
 252 rpc_clone_client(struct rpc_clnt *clnt)
 253 {
 254         struct rpc_clnt *new;
 255
 256         new = kmalloc(sizeof(*new), GFP_KERNEL);
 257         if (!new)
 258                 goto out_no_clnt;
 259         memcpy(new, clnt, sizeof(*new));
 260         atomic_set(&new->cl_count, 1);
 261         atomic_set(&new->cl_users, 0);
 262         new->cl_parent = clnt;
 263         atomic_inc(&clnt->cl_count);
 264         /* Turn off autobind on clones */
 265         new->cl_autobind = 0;
 266         new->cl_oneshot = 0;
 267         new->cl_dead = 0;
 268         if (!IS_ERR(new->cl_dentry))
 269                 dget(new->cl_dentry);
 270         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 271         if (new->cl_auth)
 272                 atomic_inc(&new->cl_auth->au_count);
 273         new->cl_metrics = rpc_alloc_iostats(clnt);
 274         return new;
 275 out_no_clnt:
 276         printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
 277         return ERR_PTR(-ENOMEM);
 278 }
 279
 280 /*
 281  * Properly shut down an RPC client, terminating all outstanding
 282  * requests. Note that we must be certain that cl_oneshot and
 283  * cl_dead are cleared, or else the client would be destroyed
 284  * when the last task releases it.
 285  */
 286 int
 287 rpc_shutdown_client(struct rpc_clnt *clnt)
 288 {
 289         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
 290                         clnt->cl_protname, clnt->cl_server,
 291                         atomic_read(&clnt->cl_users));
 292
 293         while (atomic_read(&clnt->cl_users) > 0) {
 294                 /* Don't let rpc_release_client destroy us */
 295                 clnt->cl_oneshot = 0;
 296                 clnt->cl_dead = 0;
 297                 rpc_killall_tasks(clnt);
 298                 wait_event_timeout(destroy_wait,
 299                         !atomic_read(&clnt->cl_users), 1*HZ);
 300         }
 301
 302         if (atomic_read(&clnt->cl_users) < 0) {
 303                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 304                                 clnt, atomic_read(&clnt->cl_users));
 305 #ifdef RPC_DEBUG
 306                 rpc_show_tasks();
 307 #endif
 308                 BUG();
 309         }
 310
 311         return rpc_destroy_client(clnt);
 312 }
 313
 314 /*
 315  * Delete an RPC client
 316  */
 317 int
 318 rpc_destroy_client(struct rpc_clnt *clnt)
 319 {
 320         if (!atomic_dec_and_test(&clnt->cl_count))
 321                 return 1;
 322         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 323
 324         dprintk("RPC: destroying %s client for %s\n",
 325                         clnt->cl_protname, clnt->cl_server);
 326         if (clnt->cl_auth) {
 327                 rpcauth_destroy(clnt->cl_auth);
 328                 clnt->cl_auth = NULL;
 329         }
 330         if (clnt->cl_parent != clnt) {
 331                 if (!IS_ERR(clnt->cl_dentry))
 332                         dput(clnt->cl_dentry);
 333                 rpc_destroy_client(clnt->cl_parent);
 334                 goto out_free;
 335         }
 336         if (!IS_ERR(clnt->cl_dentry)) {
 337                 rpc_rmdir(clnt->cl_dentry);
 338                 rpc_put_mount();
 339         }
 340         if (clnt->cl_xprt) {
 341                 xprt_destroy(clnt->cl_xprt);
 342                 clnt->cl_xprt = NULL;
 343         }
 344         if (clnt->cl_server != clnt->cl_inline_name)
 345                 kfree(clnt->cl_server);
 346 out_free:
 347         rpc_free_iostats(clnt->cl_metrics);
 348         clnt->cl_metrics = NULL;
 349         kfree(clnt);
 350         return 0;
 351 }
 352
 353 /*
 354  * Release an RPC client
 355  */
 356 void
 357 rpc_release_client(struct rpc_clnt *clnt)
 358 {
 359         dprintk("RPC:      rpc_release_client(%p, %d)\n",
 360                                 clnt, atomic_read(&clnt->cl_users));
 361
 362         if (!atomic_dec_and_test(&clnt->cl_users))
 363                 return;
 364         wake_up(&destroy_wait);
 365         if (clnt->cl_oneshot || clnt->cl_dead)
 366                 rpc_destroy_client(clnt);
 367 }
 368
 369 /**
 370  * rpc_bind_new_program - bind a new RPC program to an existing client
 371  * @old - old rpc_client
 372  * @program - rpc program to set
 373  * @vers - rpc program version
 374  *
 375  * Clones the rpc client and sets up a new RPC program. This is mainly
 376  * of use for enabling different RPC programs to share the same transport.
 377  * The Sun NFSv2/v3 ACL protocol can do this.
 378  */
 379 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 380                                       struct rpc_program *program,
 381                                       int vers)
 382 {
 383         struct rpc_clnt *clnt;
 384         struct rpc_version *version;
 385         int err;
 386
 387         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 388         version = program->version[vers];
 389         clnt = rpc_clone_client(old);
 390         if (IS_ERR(clnt))
 391                 goto out;
 392         clnt->cl_procinfo = version->procs;
 393         clnt->cl_maxproc  = version->nrprocs;
 394         clnt->cl_protname = program->name;
 395         clnt->cl_prog     = program->number;
 396         clnt->cl_vers     = version->number;
 397         clnt->cl_stats    = program->stats;
 398         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 399         if (err != 0) {
 400                 rpc_shutdown_client(clnt);
 401                 clnt = ERR_PTR(err);
 402         }
 403 out:
 404         return clnt;
 405 }
 406
 407 /*
 408  * Default callback for async RPC calls
 409  */
 410 static void
 411 rpc_default_callback(struct rpc_task *task, void *data)
 412 {
 413 }
 414
 415 static const struct rpc_call_ops rpc_default_ops = {
 416         .rpc_call_done = rpc_default_callback,
 417 };
 418
 419 /*
 420  *      Export the signal mask handling for synchronous code that
 421  *      sleeps on RPC calls
 422  */
 423 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 424
 425 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 426 {
 427         unsigned long   sigallow = sigmask(SIGKILL);
 428         sigset_t sigmask;
 429
 430         /* Block all signals except those listed in sigallow */
 431         if (intr)
 432                 sigallow |= RPC_INTR_SIGNALS;
 433         siginitsetinv(&sigmask, sigallow);
 434         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 435 }
 436
 437 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 438 {
 439         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 440 }
 441
 442 static inline void rpc_restore_sigmask(sigset_t *oldset)
 443 {
 444         sigprocmask(SIG_SETMASK, oldset, NULL);
 445 }
 446
 447 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 448 {
 449         rpc_save_sigmask(oldset, clnt->cl_intr);
 450 }
 451
 452 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 453 {
 454         rpc_restore_sigmask(oldset);
 455 }
 456
 457 /*
 458  * New rpc_call implementation
 459  */
 460 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 461 {
 462         struct rpc_task *task;
 463         sigset_t        oldset;
 464         int             status;
 465
 466         /* If this client is slain all further I/O fails */
 467         if (clnt->cl_dead)
 468                 return -EIO;
 469
 470         BUG_ON(flags & RPC_TASK_ASYNC);
 471
 472         status = -ENOMEM;
 473         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 474         if (task == NULL)
 475                 goto out;
 476
 477         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 478         rpc_task_sigmask(task, &oldset);
 479
 480         rpc_call_setup(task, msg, 0);
 481
 482         /* Set up the call info struct and execute the task */
 483         status = task->tk_status;
 484         if (status == 0) {
 485                 atomic_inc(&task->tk_count);
 486                 status = rpc_execute(task);
 487                 if (status == 0)
 488                         status = task->tk_status;
 489         }
 490         rpc_restore_sigmask(&oldset);
 491         rpc_release_task(task);
 492 out:
 493         return status;
 494 }
 495
 496 /*
 497  * New rpc_call implementation
 498  */
 499 int
 500 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 501                const struct rpc_call_ops *tk_ops, void *data)
 502 {
 503         struct rpc_task *task;
 504         sigset_t        oldset;
 505         int             status;
 506
 507         /* If this client is slain all further I/O fails */
 508         status = -EIO;
 509         if (clnt->cl_dead)
 510                 goto out_release;
 511
 512         flags |= RPC_TASK_ASYNC;
 513
 514         /* Create/initialize a new RPC task */
 515         status = -ENOMEM;
 516         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 517                 goto out_release;
 518
 519         /* Mask signals on GSS_AUTH upcalls */
 520         rpc_task_sigmask(task, &oldset);
 521
 522         rpc_call_setup(task, msg, 0);
 523
 524         /* Set up the call info struct and execute the task */
 525         status = task->tk_status;
 526         if (status == 0)
 527                 rpc_execute(task);
 528         else
 529                 rpc_release_task(task);
 530
 531         rpc_restore_sigmask(&oldset);
 532         return status;
 533 out_release:
 534         if (tk_ops->rpc_release != NULL)
 535                 tk_ops->rpc_release(data);
 536         return status;
 537 }
 538
 539
 540 void
 541 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 542 {
 543         task->tk_msg   = *msg;
 544         task->tk_flags |= flags;
 545         /* Bind the user cred */
 546         if (task->tk_msg.rpc_cred != NULL)
 547                 rpcauth_holdcred(task);
 548         else
 549                 rpcauth_bindcred(task);
 550
 551         if (task->tk_status == 0)
 552                 task->tk_action = call_start;
 553         else
 554                 task->tk_action = rpc_exit_task;
 555 }
 556
 557 /**
 558  * rpc_peeraddr - extract remote peer address from clnt's xprt
 559  * @clnt: RPC client structure
 560  * @buf: target buffer
 561  * @size: length of target buffer
 562  *
 563  * Returns the number of bytes that are actually in the stored address.
 564  */
 565 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 566 {
 567         size_t bytes;
 568         struct rpc_xprt *xprt = clnt->cl_xprt;
 569
 570         bytes = sizeof(xprt->addr);
 571         if (bytes > bufsize)
 572                 bytes = bufsize;
 573         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 574         return xprt->addrlen;
 575 }
 576 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 577
 578 /**
 579  * rpc_peeraddr2str - return remote peer address in printable format
 580  * @clnt: RPC client structure
 581  * @format: address format
 582  *
 583  */
 584 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 585 {
 586         struct rpc_xprt *xprt = clnt->cl_xprt;
 587         return xprt->ops->print_addr(xprt, format);
 588 }
 589 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 590
 591 void
 592 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 593 {
 594         struct rpc_xprt *xprt = clnt->cl_xprt;
 595         if (xprt->ops->set_buffer_size)
 596                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 597 }
 598
 599 /*
 600  * Return size of largest payload RPC client can support, in bytes
 601  *
 602  * For stream transports, this is one RPC record fragment (see RFC
 603  * 1831), as we don't support multi-record requests yet.  For datagram
 604  * transports, this is the size of an IP packet minus the IP, UDP, and
 605  * RPC header sizes.
 606  */
 607 size_t rpc_max_payload(struct rpc_clnt *clnt)
 608 {
 609         return clnt->cl_xprt->max_payload;
 610 }
 611 EXPORT_SYMBOL_GPL(rpc_max_payload);
 612
 613 /**
 614  * rpc_force_rebind - force transport to check that remote port is unchanged
 615  * @clnt: client to rebind
 616  *
 617  */
 618 void rpc_force_rebind(struct rpc_clnt *clnt)
 619 {
 620         if (clnt->cl_autobind)
 621                 xprt_clear_bound(clnt->cl_xprt);
 622 }
 623 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 624
 625 /*
 626  * Restart an (async) RPC call. Usually called from within the
 627  * exit handler.
 628  */
 629 void
 630 rpc_restart_call(struct rpc_task *task)
 631 {
 632         if (RPC_ASSASSINATED(task))
 633                 return;
 634
 635         task->tk_action = call_start;
 636 }
 637
 638 /*
 639  * 0.  Initial state
 640  *
 641  *     Other FSM states can be visited zero or more times, but
 642  *     this state is visited exactly once for each RPC.
 643  */
 644 static void
 645 call_start(struct rpc_task *task)
 646 {
 647         struct rpc_clnt *clnt = task->tk_client;
 648
 649         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
 650                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
 651                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
 652
 653         /* Increment call count */
 654         task->tk_msg.rpc_proc->p_count++;
 655         clnt->cl_stats->rpccnt++;
 656         task->tk_action = call_reserve;
 657 }
 658
 659 /*
 660  * 1.   Reserve an RPC call slot
 661  */
 662 static void
 663 call_reserve(struct rpc_task *task)
 664 {
 665         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
 666
 667         if (!rpcauth_uptodatecred(task)) {
 668                 task->tk_action = call_refresh;
 669                 return;
 670         }
 671
 672         task->tk_status  = 0;
 673         task->tk_action  = call_reserveresult;
 674         xprt_reserve(task);
 675 }
 676
 677 /*
 678  * 1b.  Grok the result of xprt_reserve()
 679  */
 680 static void
 681 call_reserveresult(struct rpc_task *task)
 682 {
 683         int status = task->tk_status;
 684
 685         dprintk("RPC: %4d call_reserveresult (status %d)\n",
 686                                 task->tk_pid, task->tk_status);
 687
 688         /*
 689          * After a call to xprt_reserve(), we must have either
 690          * a request slot or else an error status.
 691          */
 692         task->tk_status = 0;
 693         if (status >= 0) {
 694                 if (task->tk_rqstp) {
 695                         task->tk_action = call_allocate;
 696                         return;
 697                 }
 698
 699                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 700                                 __FUNCTION__, status);
 701                 rpc_exit(task, -EIO);
 702                 return;
 703         }
 704
 705         /*
 706          * Even though there was an error, we may have acquired
 707          * a request slot somehow.  Make sure not to leak it.
 708          */
 709         if (task->tk_rqstp) {
 710                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 711                                 __FUNCTION__, status);
 712                 xprt_release(task);
 713         }
 714
 715         switch (status) {
 716         case -EAGAIN:   /* woken up; retry */
 717                 task->tk_action = call_reserve;
 718                 return;
 719         case -EIO:      /* probably a shutdown */
 720                 break;
 721         default:
 722                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 723                                 __FUNCTION__, status);
 724                 break;
 725         }
 726         rpc_exit(task, status);
 727 }
 728
 729 /*
 730  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 731  *      (Note: buffer memory is freed in xprt_release).
 732  */
 733 static void
 734 call_allocate(struct rpc_task *task)
 735 {
 736         struct rpc_rqst *req = task->tk_rqstp;
 737         struct rpc_xprt *xprt = task->tk_xprt;
 738         unsigned int    bufsiz;
 739
 740         dprintk("RPC: %4d call_allocate (status %d)\n",
 741                                 task->tk_pid, task->tk_status);
 742         task->tk_action = call_bind;
 743         if (req->rq_buffer)
 744                 return;
 745
 746         /* FIXME: compute buffer requirements more exactly using
 747          * auth->au_wslack */
 748         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 749
 750         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 751                 return;
 752         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task);
 753
 754         if (RPC_IS_ASYNC(task) || !signalled()) {
 755                 xprt_release(task);
 756                 task->tk_action = call_reserve;
 757                 rpc_delay(task, HZ>>4);
 758                 return;
 759         }
 760
 761         rpc_exit(task, -ERESTARTSYS);
 762 }
 763
 764 static inline int
 765 rpc_task_need_encode(struct rpc_task *task)
 766 {
 767         return task->tk_rqstp->rq_snd_buf.len == 0;
 768 }
 769
 770 static inline void
 771 rpc_task_force_reencode(struct rpc_task *task)
 772 {
 773         task->tk_rqstp->rq_snd_buf.len = 0;
 774 }
 775
 776 /*
 777  * 3.   Encode arguments of an RPC call
 778  */
 779 static void
 780 call_encode(struct rpc_task *task)
 781 {
 782         struct rpc_rqst *req = task->tk_rqstp;
 783         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 784         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 785         unsigned int    bufsiz;
 786         kxdrproc_t      encode;
 787         u32             *p;
 788
 789         dprintk("RPC: %4d call_encode (status %d)\n",
 790                                 task->tk_pid, task->tk_status);
 791
 792         /* Default buffer setup */
 793         bufsiz = req->rq_bufsize >> 1;
 794         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 795         sndbuf->head[0].iov_len  = bufsiz;
 796         sndbuf->tail[0].iov_len  = 0;
 797         sndbuf->page_len         = 0;
 798         sndbuf->len              = 0;
 799         sndbuf->buflen           = bufsiz;
 800         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 801         rcvbuf->head[0].iov_len  = bufsiz;
 802         rcvbuf->tail[0].iov_len  = 0;
 803         rcvbuf->page_len         = 0;
 804         rcvbuf->len              = 0;
 805         rcvbuf->buflen           = bufsiz;
 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         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 818                         task->tk_msg.rpc_argp);
 819         if (task->tk_status == -ENOMEM) {
 820                 /* XXX: Is this sane? */
 821                 rpc_delay(task, 3*HZ);
 822                 task->tk_status = -EAGAIN;
 823         }
 824 }
 825
 826 /*
 827  * 4.   Get the server port number if not yet set
 828  */
 829 static void
 830 call_bind(struct rpc_task *task)
 831 {
 832         struct rpc_xprt *xprt = task->tk_xprt;
 833
 834         dprintk("RPC: %4d call_bind (status %d)\n",
 835                                 task->tk_pid, task->tk_status);
 836
 837         task->tk_action = call_connect;
 838         if (!xprt_bound(xprt)) {
 839                 task->tk_action = call_bind_status;
 840                 task->tk_timeout = xprt->bind_timeout;
 841                 xprt->ops->rpcbind(task);
 842         }
 843 }
 844
 845 /*
 846  * 4a.  Sort out bind result
 847  */
 848 static void
 849 call_bind_status(struct rpc_task *task)
 850 {
 851         int status = -EACCES;
 852
 853         if (task->tk_status >= 0) {
 854                 dprintk("RPC: %4d call_bind_status (status %d)\n",
 855                                         task->tk_pid, task->tk_status);
 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: %4d remote rpcbind: RPC program/version unavailable\n",
 864                                 task->tk_pid);
 865                 rpc_delay(task, 3*HZ);
 866                 goto retry_bind;
 867         case -ETIMEDOUT:
 868                 dprintk("RPC: %4d rpcbind request timed out\n",
 869                                 task->tk_pid);
 870                 if (RPC_IS_SOFT(task)) {
 871                         status = -EIO;
 872                         break;
 873                 }
 874                 goto retry_bind;
 875         case -EPFNOSUPPORT:
 876                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
 877                                 task->tk_pid);
 878                 break;
 879         case -EPROTONOSUPPORT:
 880                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
 881                                 task->tk_pid);
 882                 break;
 883         default:
 884                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
 885                                 task->tk_pid, -task->tk_status);
 886                 status = -EIO;
 887                 break;
 888         }
 889
 890         rpc_exit(task, status);
 891         return;
 892
 893 retry_bind:
 894         task->tk_status = 0;
 895         task->tk_action = call_bind;
 896         return;
 897 }
 898
 899 /*
 900  * 4b.  Connect to the RPC server
 901  */
 902 static void
 903 call_connect(struct rpc_task *task)
 904 {
 905         struct rpc_xprt *xprt = task->tk_xprt;
 906
 907         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
 908                         task->tk_pid, xprt,
 909                         (xprt_connected(xprt) ? "is" : "is not"));
 910
 911         task->tk_action = call_transmit;
 912         if (!xprt_connected(xprt)) {
 913                 task->tk_action = call_connect_status;
 914                 if (task->tk_status < 0)
 915                         return;
 916                 xprt_connect(task);
 917         }
 918 }
 919
 920 /*
 921  * 4c.  Sort out connect result
 922  */
 923 static void
 924 call_connect_status(struct rpc_task *task)
 925 {
 926         struct rpc_clnt *clnt = task->tk_client;
 927         int status = task->tk_status;
 928
 929         dprintk("RPC: %5u call_connect_status (status %d)\n",
 930                                 task->tk_pid, task->tk_status);
 931
 932         task->tk_status = 0;
 933         if (status >= 0) {
 934                 clnt->cl_stats->netreconn++;
 935                 task->tk_action = call_transmit;
 936                 return;
 937         }
 938
 939         /* Something failed: remote service port may have changed */
 940         rpc_force_rebind(clnt);
 941
 942         switch (status) {
 943         case -ENOTCONN:
 944         case -ETIMEDOUT:
 945         case -EAGAIN:
 946                 task->tk_action = call_bind;
 947                 break;
 948         default:
 949                 rpc_exit(task, -EIO);
 950                 break;
 951         }
 952 }
 953
 954 /*
 955  * 5.   Transmit the RPC request, and wait for reply
 956  */
 957 static void
 958 call_transmit(struct rpc_task *task)
 959 {
 960         dprintk("RPC: %4d call_transmit (status %d)\n",
 961                                 task->tk_pid, task->tk_status);
 962
 963         task->tk_action = call_status;
 964         if (task->tk_status < 0)
 965                 return;
 966         task->tk_status = xprt_prepare_transmit(task);
 967         if (task->tk_status != 0)
 968                 return;
 969         task->tk_action = call_transmit_status;
 970         /* Encode here so that rpcsec_gss can use correct sequence number. */
 971         if (rpc_task_need_encode(task)) {
 972                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 973                 call_encode(task);
 974                 /* Did the encode result in an error condition? */
 975                 if (task->tk_status != 0)
 976                         return;
 977         }
 978         xprt_transmit(task);
 979         if (task->tk_status < 0)
 980                 return;
 981         /*
 982          * On success, ensure that we call xprt_end_transmit() before sleeping
 983          * in order to allow access to the socket to other RPC requests.
 984          */
 985         call_transmit_status(task);
 986         if (task->tk_msg.rpc_proc->p_decode != NULL)
 987                 return;
 988         task->tk_action = rpc_exit_task;
 989         rpc_wake_up_task(task);
 990 }
 991
 992 /*
 993  * 5a.  Handle cleanup after a transmission
 994  */
 995 static void
 996 call_transmit_status(struct rpc_task *task)
 997 {
 998         task->tk_action = call_status;
 999         /*
1000          * Special case: if we've been waiting on the socket's write_space()
1001          * callback, then don't call xprt_end_transmit().
1002          */
1003         if (task->tk_status == -EAGAIN)
1004                 return;
1005         xprt_end_transmit(task);
1006         rpc_task_force_reencode(task);
1007 }
1008
1009 /*
1010  * 6.   Sort out the RPC call status
1011  */
1012 static void
1013 call_status(struct rpc_task *task)
1014 {
1015         struct rpc_clnt *clnt = task->tk_client;
1016         struct rpc_rqst *req = task->tk_rqstp;
1017         int             status;
1018
1019         if (req->rq_received > 0 && !req->rq_bytes_sent)
1020                 task->tk_status = req->rq_received;
1021
1022         dprintk("RPC: %4d call_status (status %d)\n",
1023                                 task->tk_pid, task->tk_status);
1024
1025         status = task->tk_status;
1026         if (status >= 0) {
1027                 task->tk_action = call_decode;
1028                 return;
1029         }
1030
1031         task->tk_status = 0;
1032         switch(status) {
1033         case -ETIMEDOUT:
1034                 task->tk_action = call_timeout;
1035                 break;
1036         case -ECONNREFUSED:
1037         case -ENOTCONN:
1038                 rpc_force_rebind(clnt);
1039                 task->tk_action = call_bind;
1040                 break;
1041         case -EAGAIN:
1042                 task->tk_action = call_transmit;
1043                 break;
1044         case -EIO:
1045                 /* shutdown or soft timeout */
1046                 rpc_exit(task, status);
1047                 break;
1048         default:
1049                 printk("%s: RPC call returned error %d\n",
1050                                clnt->cl_protname, -status);
1051                 rpc_exit(task, status);
1052                 break;
1053         }
1054 }
1055
1056 /*
1057  * 6a.  Handle RPC timeout
1058  *      We do not release the request slot, so we keep using the
1059  *      same XID for all retransmits.
1060  */
1061 static void
1062 call_timeout(struct rpc_task *task)
1063 {
1064         struct rpc_clnt *clnt = task->tk_client;
1065
1066         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1067                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1068                 goto retry;
1069         }
1070
1071         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1072         task->tk_timeouts++;
1073
1074         if (RPC_IS_SOFT(task)) {
1075                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1076                                 clnt->cl_protname, clnt->cl_server);
1077                 rpc_exit(task, -EIO);
1078                 return;
1079         }
1080
1081         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1082                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1083                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1084                         clnt->cl_protname, clnt->cl_server);
1085         }
1086         rpc_force_rebind(clnt);
1087
1088 retry:
1089         clnt->cl_stats->rpcretrans++;
1090         task->tk_action = call_bind;
1091         task->tk_status = 0;
1092 }
1093
1094 /*
1095  * 7.   Decode the RPC reply
1096  */
1097 static void
1098 call_decode(struct rpc_task *task)
1099 {
1100         struct rpc_clnt *clnt = task->tk_client;
1101         struct rpc_rqst *req = task->tk_rqstp;
1102         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1103         u32             *p;
1104
1105         dprintk("RPC: %4d call_decode (status %d)\n",
1106                                 task->tk_pid, task->tk_status);
1107
1108         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1109                 printk(KERN_NOTICE "%s: server %s OK\n",
1110                         clnt->cl_protname, clnt->cl_server);
1111                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1112         }
1113
1114         if (task->tk_status < 12) {
1115                 if (!RPC_IS_SOFT(task)) {
1116                         task->tk_action = call_bind;
1117                         clnt->cl_stats->rpcretrans++;
1118                         goto out_retry;
1119                 }
1120                 printk(KERN_WARNING "%s: too small RPC reply size (%d bytes)\n",
1121                         clnt->cl_protname, task->tk_status);
1122                 rpc_exit(task, -EIO);
1123                 return;
1124         }
1125
1126         /*
1127          * Ensure that we see all writes made by xprt_complete_rqst()
1128          * before it changed req->rq_received.
1129          */
1130         smp_rmb();
1131         req->rq_rcv_buf.len = req->rq_private_buf.len;
1132
1133         /* Check that the softirq receive buffer is valid */
1134         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1135                                 sizeof(req->rq_rcv_buf)) != 0);
1136
1137         /* Verify the RPC header */
1138         p = call_verify(task);
1139         if (IS_ERR(p)) {
1140                 if (p == ERR_PTR(-EAGAIN))
1141                         goto out_retry;
1142                 return;
1143         }
1144
1145         task->tk_action = rpc_exit_task;
1146
1147         if (decode)
1148                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1149                                                       task->tk_msg.rpc_resp);
1150         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1151                                         task->tk_status);
1152         return;
1153 out_retry:
1154         req->rq_received = req->rq_private_buf.len = 0;
1155         task->tk_status = 0;
1156 }
1157
1158 /*
1159  * 8.   Refresh the credentials if rejected by the server
1160  */
1161 static void
1162 call_refresh(struct rpc_task *task)
1163 {
1164         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1165
1166         xprt_release(task);     /* Must do to obtain new XID */
1167         task->tk_action = call_refreshresult;
1168         task->tk_status = 0;
1169         task->tk_client->cl_stats->rpcauthrefresh++;
1170         rpcauth_refreshcred(task);
1171 }
1172
1173 /*
1174  * 8a.  Process the results of a credential refresh
1175  */
1176 static void
1177 call_refreshresult(struct rpc_task *task)
1178 {
1179         int status = task->tk_status;
1180         dprintk("RPC: %4d call_refreshresult (status %d)\n",
1181                                 task->tk_pid, task->tk_status);
1182
1183         task->tk_status = 0;
1184         task->tk_action = call_reserve;
1185         if (status >= 0 && rpcauth_uptodatecred(task))
1186                 return;
1187         if (status == -EACCES) {
1188                 rpc_exit(task, -EACCES);
1189                 return;
1190         }
1191         task->tk_action = call_refresh;
1192         if (status != -ETIMEDOUT)
1193                 rpc_delay(task, 3*HZ);
1194         return;
1195 }
1196
1197 /*
1198  * Call header serialization
1199  */
1200 static u32 *
1201 call_header(struct rpc_task *task)
1202 {
1203         struct rpc_clnt *clnt = task->tk_client;
1204         struct rpc_rqst *req = task->tk_rqstp;
1205         u32             *p = req->rq_svec[0].iov_base;
1206
1207         /* FIXME: check buffer size? */
1208
1209         p = xprt_skip_transport_header(task->tk_xprt, p);
1210         *p++ = req->rq_xid;             /* XID */
1211         *p++ = htonl(RPC_CALL);         /* CALL */
1212         *p++ = htonl(RPC_VERSION);      /* RPC version */
1213         *p++ = htonl(clnt->cl_prog);    /* program number */
1214         *p++ = htonl(clnt->cl_vers);    /* program version */
1215         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1216         p = rpcauth_marshcred(task, p);
1217         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1218         return p;
1219 }
1220
1221 /*
1222  * Reply header verification
1223  */
1224 static u32 *
1225 call_verify(struct rpc_task *task)
1226 {
1227         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1228         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1229         u32     *p = iov->iov_base, n;
1230         int error = -EACCES;
1231
1232         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1233                 /* RFC-1014 says that the representation of XDR data must be a
1234                  * multiple of four bytes
1235                  * - if it isn't pointer subtraction in the NFS client may give
1236                  *   undefined results
1237                  */
1238                 printk(KERN_WARNING
1239                        "call_verify: XDR representation not a multiple of"
1240                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1241                 goto out_eio;
1242         }
1243         if ((len -= 3) < 0)
1244                 goto out_overflow;
1245         p += 1; /* skip XID */
1246
1247         if ((n = ntohl(*p++)) != RPC_REPLY) {
1248                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1249                 goto out_garbage;
1250         }
1251         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1252                 if (--len < 0)
1253                         goto out_overflow;
1254                 switch ((n = ntohl(*p++))) {
1255                         case RPC_AUTH_ERROR:
1256                                 break;
1257                         case RPC_MISMATCH:
1258                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1259                                 error = -EPROTONOSUPPORT;
1260                                 goto out_err;
1261                         default:
1262                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1263                                 goto out_eio;
1264                 }
1265                 if (--len < 0)
1266                         goto out_overflow;
1267                 switch ((n = ntohl(*p++))) {
1268                 case RPC_AUTH_REJECTEDCRED:
1269                 case RPC_AUTH_REJECTEDVERF:
1270                 case RPCSEC_GSS_CREDPROBLEM:
1271                 case RPCSEC_GSS_CTXPROBLEM:
1272                         if (!task->tk_cred_retry)
1273                                 break;
1274                         task->tk_cred_retry--;
1275                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1276                                                         task->tk_pid);
1277                         rpcauth_invalcred(task);
1278                         task->tk_action = call_refresh;
1279                         goto out_retry;
1280                 case RPC_AUTH_BADCRED:
1281                 case RPC_AUTH_BADVERF:
1282                         /* possibly garbled cred/verf? */
1283                         if (!task->tk_garb_retry)
1284                                 break;
1285                         task->tk_garb_retry--;
1286                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1287                                                         task->tk_pid);
1288                         task->tk_action = call_bind;
1289                         goto out_retry;
1290                 case RPC_AUTH_TOOWEAK:
1291                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1292                                "authentication.\n", task->tk_client->cl_server);
1293                         break;
1294                 default:
1295                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1296                         error = -EIO;
1297                 }
1298                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1299                                                 task->tk_pid, n);
1300                 goto out_err;
1301         }
1302         if (!(p = rpcauth_checkverf(task, p))) {
1303                 printk(KERN_WARNING "call_verify: auth check failed\n");
1304                 goto out_garbage;               /* bad verifier, retry */
1305         }
1306         len = p - (u32 *)iov->iov_base - 1;
1307         if (len < 0)
1308                 goto out_overflow;
1309         switch ((n = ntohl(*p++))) {
1310         case RPC_SUCCESS:
1311                 return p;
1312         case RPC_PROG_UNAVAIL:
1313                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1314                                 (unsigned int)task->tk_client->cl_prog,
1315                                 task->tk_client->cl_server);
1316                 error = -EPFNOSUPPORT;
1317                 goto out_err;
1318         case RPC_PROG_MISMATCH:
1319                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1320                                 (unsigned int)task->tk_client->cl_prog,
1321                                 (unsigned int)task->tk_client->cl_vers,
1322                                 task->tk_client->cl_server);
1323                 error = -EPROTONOSUPPORT;
1324                 goto out_err;
1325         case RPC_PROC_UNAVAIL:
1326                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1327                                 task->tk_msg.rpc_proc,
1328                                 task->tk_client->cl_prog,
1329                                 task->tk_client->cl_vers,
1330                                 task->tk_client->cl_server);
1331                 error = -EOPNOTSUPP;
1332                 goto out_err;
1333         case RPC_GARBAGE_ARGS:
1334                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1335                 break;                  /* retry */
1336         default:
1337                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1338                 /* Also retry */
1339         }
1340
1341 out_garbage:
1342         task->tk_client->cl_stats->rpcgarbage++;
1343         if (task->tk_garb_retry) {
1344                 task->tk_garb_retry--;
1345                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1346                 task->tk_action = call_bind;
1347 out_retry:
1348                 return ERR_PTR(-EAGAIN);
1349         }
1350         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1351 out_eio:
1352         error = -EIO;
1353 out_err:
1354         rpc_exit(task, error);
1355         return ERR_PTR(error);
1356 out_overflow:
1357         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1358         goto out_garbage;
1359 }
1360
1361 static int rpcproc_encode_null(void *rqstp, u32 *data, void *obj)
1362 {
1363         return 0;
1364 }
1365
1366 static int rpcproc_decode_null(void *rqstp, u32 *data, void *obj)
1367 {
1368         return 0;
1369 }
1370
1371 static struct rpc_procinfo rpcproc_null = {
1372         .p_encode = rpcproc_encode_null,
1373         .p_decode = rpcproc_decode_null,
1374 };
1375
1376 int rpc_ping(struct rpc_clnt *clnt, int flags)
1377 {
1378         struct rpc_message msg = {
1379                 .rpc_proc = &rpcproc_null,
1380         };
1381         int err;
1382         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1383         err = rpc_call_sync(clnt, &msg, flags);
1384         put_rpccred(msg.rpc_cred);
1385         return err;
1386 }