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 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
  40
  41 #ifdef RPC_DEBUG
  42 # define RPCDBG_FACILITY        RPCDBG_CALL
  43 #endif
  44
  45 #define dprint_status(t)                                        \
  46         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  47                         __FUNCTION__, t->tk_status)
  48
  49 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  50
  51
  52 static void     call_start(struct rpc_task *task);
  53 static void     call_reserve(struct rpc_task *task);
  54 static void     call_reserveresult(struct rpc_task *task);
  55 static void     call_allocate(struct rpc_task *task);
  56 static void     call_encode(struct rpc_task *task);
  57 static void     call_decode(struct rpc_task *task);
  58 static void     call_bind(struct rpc_task *task);
  59 static void     call_bind_status(struct rpc_task *task);
  60 static void     call_transmit(struct rpc_task *task);
  61 static void     call_status(struct rpc_task *task);
  62 static void     call_transmit_status(struct rpc_task *task);
  63 static void     call_refresh(struct rpc_task *task);
  64 static void     call_refreshresult(struct rpc_task *task);
  65 static void     call_timeout(struct rpc_task *task);
  66 static void     call_connect(struct rpc_task *task);
  67 static void     call_connect_status(struct rpc_task *task);
  68 static __be32 * call_header(struct rpc_task *task);
  69 static __be32 * call_verify(struct rpc_task *task);
  70
  71
  72 static int
  73 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  74 {
  75         static uint32_t clntid;
  76         int error;
  77
  78         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  79         clnt->cl_dentry = ERR_PTR(-ENOENT);
  80         if (dir_name == NULL)
  81                 return 0;
  82
  83         clnt->cl_vfsmnt = rpc_get_mount();
  84         if (IS_ERR(clnt->cl_vfsmnt))
  85                 return PTR_ERR(clnt->cl_vfsmnt);
  86
  87         for (;;) {
  88                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  89                                 "%s/clnt%x", dir_name,
  90                                 (unsigned int)clntid++);
  91                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  92                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  93                 if (!IS_ERR(clnt->cl_dentry))
  94                         return 0;
  95                 error = PTR_ERR(clnt->cl_dentry);
  96                 if (error != -EEXIST) {
  97                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  98                                         clnt->cl_pathname, error);
  99                         rpc_put_mount();
 100                         return error;
 101                 }
 102         }
 103 }
 104
 105 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
 106 {
 107         struct rpc_version      *version;
 108         struct rpc_clnt         *clnt = NULL;
 109         struct rpc_auth         *auth;
 110         int err;
 111         int len;
 112
 113         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 114                         program->name, servname, xprt);
 115
 116         err = -EINVAL;
 117         if (!xprt)
 118                 goto out_no_xprt;
 119         if (vers >= program->nrvers || !(version = program->version[vers]))
 120                 goto out_err;
 121
 122         err = -ENOMEM;
 123         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 124         if (!clnt)
 125                 goto out_err;
 126         atomic_set(&clnt->cl_users, 0);
 127         atomic_set(&clnt->cl_count, 1);
 128         clnt->cl_parent = clnt;
 129
 130         clnt->cl_server = clnt->cl_inline_name;
 131         len = strlen(servname) + 1;
 132         if (len > sizeof(clnt->cl_inline_name)) {
 133                 char *buf = kmalloc(len, GFP_KERNEL);
 134                 if (buf != 0)
 135                         clnt->cl_server = buf;
 136                 else
 137                         len = sizeof(clnt->cl_inline_name);
 138         }
 139         strlcpy(clnt->cl_server, servname, len);
 140
 141         clnt->cl_xprt     = xprt;
 142         clnt->cl_procinfo = version->procs;
 143         clnt->cl_maxproc  = version->nrprocs;
 144         clnt->cl_protname = program->name;
 145         clnt->cl_prog     = program->number;
 146         clnt->cl_vers     = version->number;
 147         clnt->cl_stats    = program->stats;
 148         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 149         err = -ENOMEM;
 150         if (clnt->cl_metrics == NULL)
 151                 goto out_no_stats;
 152         clnt->cl_program  = program;
 153
 154         if (!xprt_bound(clnt->cl_xprt))
 155                 clnt->cl_autobind = 1;
 156
 157         clnt->cl_rtt = &clnt->cl_rtt_default;
 158         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 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         return clnt;
 178
 179 out_no_auth:
 180         if (!IS_ERR(clnt->cl_dentry)) {
 181                 rpc_rmdir(clnt->cl_dentry);
 182                 rpc_put_mount();
 183         }
 184 out_no_path:
 185         rpc_free_iostats(clnt->cl_metrics);
 186 out_no_stats:
 187         if (clnt->cl_server != clnt->cl_inline_name)
 188                 kfree(clnt->cl_server);
 189         kfree(clnt);
 190 out_err:
 191         xprt_put(xprt);
 192 out_no_xprt:
 193         return ERR_PTR(err);
 194 }
 195
 196 /*
 197  * rpc_create - create an RPC client and transport with one call
 198  * @args: rpc_clnt create argument structure
 199  *
 200  * Creates and initializes an RPC transport and an RPC client.
 201  *
 202  * It can ping the server in order to determine if it is up, and to see if
 203  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 204  * this behavior so asynchronous tasks can also use rpc_create.
 205  */
 206 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 207 {
 208         struct rpc_xprt *xprt;
 209         struct rpc_clnt *clnt;
 210
 211         xprt = xprt_create_transport(args->protocol, args->address,
 212                                         args->addrsize, args->timeout);
 213         if (IS_ERR(xprt))
 214                 return (struct rpc_clnt *)xprt;
 215
 216         /*
 217          * By default, kernel RPC client connects from a reserved port.
 218          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 219          * but it is always enabled for rpciod, which handles the connect
 220          * operation.
 221          */
 222         xprt->resvport = 1;
 223         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 224                 xprt->resvport = 0;
 225
 226         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 227                         args->program->name, args->servername, xprt);
 228
 229         clnt = rpc_new_client(xprt, args->servername, args->program,
 230                                 args->version, args->authflavor);
 231         if (IS_ERR(clnt))
 232                 return clnt;
 233
 234         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 235                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 236                 if (err != 0) {
 237                         rpc_shutdown_client(clnt);
 238                         return ERR_PTR(err);
 239                 }
 240         }
 241
 242         clnt->cl_softrtry = 1;
 243         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 244                 clnt->cl_softrtry = 0;
 245
 246         if (args->flags & RPC_CLNT_CREATE_INTR)
 247                 clnt->cl_intr = 1;
 248         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 249                 clnt->cl_autobind = 1;
 250         if (args->flags & RPC_CLNT_CREATE_ONESHOT)
 251                 clnt->cl_oneshot = 1;
 252         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 253                 clnt->cl_discrtry = 1;
 254
 255         return clnt;
 256 }
 257 EXPORT_SYMBOL_GPL(rpc_create);
 258
 259 /*
 260  * This function clones the RPC client structure. It allows us to share the
 261  * same transport while varying parameters such as the authentication
 262  * flavour.
 263  */
 264 struct rpc_clnt *
 265 rpc_clone_client(struct rpc_clnt *clnt)
 266 {
 267         struct rpc_clnt *new;
 268         int err = -ENOMEM;
 269
 270         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 271         if (!new)
 272                 goto out_no_clnt;
 273         atomic_set(&new->cl_count, 1);
 274         atomic_set(&new->cl_users, 0);
 275         new->cl_metrics = rpc_alloc_iostats(clnt);
 276         if (new->cl_metrics == NULL)
 277                 goto out_no_stats;
 278         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 279         if (err != 0)
 280                 goto out_no_path;
 281         new->cl_parent = clnt;
 282         atomic_inc(&clnt->cl_count);
 283         new->cl_xprt = xprt_get(clnt->cl_xprt);
 284         /* Turn off autobind on clones */
 285         new->cl_autobind = 0;
 286         new->cl_oneshot = 0;
 287         new->cl_dead = 0;
 288         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 289         if (new->cl_auth)
 290                 atomic_inc(&new->cl_auth->au_count);
 291         return new;
 292 out_no_path:
 293         rpc_free_iostats(new->cl_metrics);
 294 out_no_stats:
 295         kfree(new);
 296 out_no_clnt:
 297         dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
 298         return ERR_PTR(err);
 299 }
 300
 301 /*
 302  * Properly shut down an RPC client, terminating all outstanding
 303  * requests. Note that we must be certain that cl_oneshot and
 304  * cl_dead are cleared, or else the client would be destroyed
 305  * when the last task releases it.
 306  */
 307 int
 308 rpc_shutdown_client(struct rpc_clnt *clnt)
 309 {
 310         dprintk("RPC:       shutting down %s client for %s, tasks=%d\n",
 311                         clnt->cl_protname, clnt->cl_server,
 312                         atomic_read(&clnt->cl_users));
 313
 314         while (atomic_read(&clnt->cl_users) > 0) {
 315                 /* Don't let rpc_release_client destroy us */
 316                 clnt->cl_oneshot = 0;
 317                 clnt->cl_dead = 0;
 318                 rpc_killall_tasks(clnt);
 319                 wait_event_timeout(destroy_wait,
 320                         !atomic_read(&clnt->cl_users), 1*HZ);
 321         }
 322
 323         if (atomic_read(&clnt->cl_users) < 0) {
 324                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 325                                 clnt, atomic_read(&clnt->cl_users));
 326 #ifdef RPC_DEBUG
 327                 rpc_show_tasks();
 328 #endif
 329                 BUG();
 330         }
 331
 332         return rpc_destroy_client(clnt);
 333 }
 334
 335 /*
 336  * Delete an RPC client
 337  */
 338 int
 339 rpc_destroy_client(struct rpc_clnt *clnt)
 340 {
 341         if (!atomic_dec_and_test(&clnt->cl_count))
 342                 return 1;
 343         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 344
 345         dprintk("RPC:       destroying %s client for %s\n",
 346                         clnt->cl_protname, clnt->cl_server);
 347         if (clnt->cl_auth) {
 348                 rpcauth_destroy(clnt->cl_auth);
 349                 clnt->cl_auth = NULL;
 350         }
 351         if (!IS_ERR(clnt->cl_dentry)) {
 352                 rpc_rmdir(clnt->cl_dentry);
 353                 rpc_put_mount();
 354         }
 355         if (clnt->cl_parent != clnt) {
 356                 rpc_destroy_client(clnt->cl_parent);
 357                 goto out_free;
 358         }
 359         if (clnt->cl_server != clnt->cl_inline_name)
 360                 kfree(clnt->cl_server);
 361 out_free:
 362         rpc_free_iostats(clnt->cl_metrics);
 363         clnt->cl_metrics = NULL;
 364         xprt_put(clnt->cl_xprt);
 365         kfree(clnt);
 366         return 0;
 367 }
 368
 369 /*
 370  * Release an RPC client
 371  */
 372 void
 373 rpc_release_client(struct rpc_clnt *clnt)
 374 {
 375         dprintk("RPC:       rpc_release_client(%p, %d)\n",
 376                         clnt, atomic_read(&clnt->cl_users));
 377
 378         if (!atomic_dec_and_test(&clnt->cl_users))
 379                 return;
 380         wake_up(&destroy_wait);
 381         if (clnt->cl_oneshot || clnt->cl_dead)
 382                 rpc_destroy_client(clnt);
 383 }
 384
 385 /**
 386  * rpc_bind_new_program - bind a new RPC program to an existing client
 387  * @old - old rpc_client
 388  * @program - rpc program to set
 389  * @vers - rpc program version
 390  *
 391  * Clones the rpc client and sets up a new RPC program. This is mainly
 392  * of use for enabling different RPC programs to share the same transport.
 393  * The Sun NFSv2/v3 ACL protocol can do this.
 394  */
 395 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 396                                       struct rpc_program *program,
 397                                       int vers)
 398 {
 399         struct rpc_clnt *clnt;
 400         struct rpc_version *version;
 401         int err;
 402
 403         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 404         version = program->version[vers];
 405         clnt = rpc_clone_client(old);
 406         if (IS_ERR(clnt))
 407                 goto out;
 408         clnt->cl_procinfo = version->procs;
 409         clnt->cl_maxproc  = version->nrprocs;
 410         clnt->cl_protname = program->name;
 411         clnt->cl_prog     = program->number;
 412         clnt->cl_vers     = version->number;
 413         clnt->cl_stats    = program->stats;
 414         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 415         if (err != 0) {
 416                 rpc_shutdown_client(clnt);
 417                 clnt = ERR_PTR(err);
 418         }
 419 out:
 420         return clnt;
 421 }
 422
 423 /*
 424  * Default callback for async RPC calls
 425  */
 426 static void
 427 rpc_default_callback(struct rpc_task *task, void *data)
 428 {
 429 }
 430
 431 static const struct rpc_call_ops rpc_default_ops = {
 432         .rpc_call_done = rpc_default_callback,
 433 };
 434
 435 /*
 436  *      Export the signal mask handling for synchronous code that
 437  *      sleeps on RPC calls
 438  */
 439 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 440
 441 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 442 {
 443         unsigned long   sigallow = sigmask(SIGKILL);
 444         sigset_t sigmask;
 445
 446         /* Block all signals except those listed in sigallow */
 447         if (intr)
 448                 sigallow |= RPC_INTR_SIGNALS;
 449         siginitsetinv(&sigmask, sigallow);
 450         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 451 }
 452
 453 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 454 {
 455         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 456 }
 457
 458 static inline void rpc_restore_sigmask(sigset_t *oldset)
 459 {
 460         sigprocmask(SIG_SETMASK, oldset, NULL);
 461 }
 462
 463 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 464 {
 465         rpc_save_sigmask(oldset, clnt->cl_intr);
 466 }
 467
 468 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 469 {
 470         rpc_restore_sigmask(oldset);
 471 }
 472
 473 /*
 474  * New rpc_call implementation
 475  */
 476 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 477 {
 478         struct rpc_task *task;
 479         sigset_t        oldset;
 480         int             status;
 481
 482         /* If this client is slain all further I/O fails */
 483         if (clnt->cl_dead)
 484                 return -EIO;
 485
 486         BUG_ON(flags & RPC_TASK_ASYNC);
 487
 488         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 489         if (task == NULL)
 490                 return -ENOMEM;
 491
 492         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 493         rpc_task_sigmask(task, &oldset);
 494
 495         /* Set up the call info struct and execute the task */
 496         rpc_call_setup(task, msg, 0);
 497         if (task->tk_status == 0) {
 498                 atomic_inc(&task->tk_count);
 499                 rpc_execute(task);
 500         }
 501         status = task->tk_status;
 502         rpc_put_task(task);
 503         rpc_restore_sigmask(&oldset);
 504         return status;
 505 }
 506
 507 /*
 508  * New rpc_call implementation
 509  */
 510 int
 511 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 512                const struct rpc_call_ops *tk_ops, void *data)
 513 {
 514         struct rpc_task *task;
 515         sigset_t        oldset;
 516         int             status;
 517
 518         /* If this client is slain all further I/O fails */
 519         status = -EIO;
 520         if (clnt->cl_dead)
 521                 goto out_release;
 522
 523         flags |= RPC_TASK_ASYNC;
 524
 525         /* Create/initialize a new RPC task */
 526         status = -ENOMEM;
 527         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 528                 goto out_release;
 529
 530         /* Mask signals on GSS_AUTH upcalls */
 531         rpc_task_sigmask(task, &oldset);
 532
 533         rpc_call_setup(task, msg, 0);
 534
 535         /* Set up the call info struct and execute the task */
 536         status = task->tk_status;
 537         if (status == 0)
 538                 rpc_execute(task);
 539         else
 540                 rpc_put_task(task);
 541
 542         rpc_restore_sigmask(&oldset);
 543         return status;
 544 out_release:
 545         rpc_release_calldata(tk_ops, data);
 546         return status;
 547 }
 548
 549
 550 void
 551 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 552 {
 553         task->tk_msg   = *msg;
 554         task->tk_flags |= flags;
 555         /* Bind the user cred */
 556         if (task->tk_msg.rpc_cred != NULL)
 557                 rpcauth_holdcred(task);
 558         else
 559                 rpcauth_bindcred(task);
 560
 561         if (task->tk_status == 0)
 562                 task->tk_action = call_start;
 563         else
 564                 task->tk_action = rpc_exit_task;
 565 }
 566
 567 /**
 568  * rpc_peeraddr - extract remote peer address from clnt's xprt
 569  * @clnt: RPC client structure
 570  * @buf: target buffer
 571  * @size: length of target buffer
 572  *
 573  * Returns the number of bytes that are actually in the stored address.
 574  */
 575 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 576 {
 577         size_t bytes;
 578         struct rpc_xprt *xprt = clnt->cl_xprt;
 579
 580         bytes = sizeof(xprt->addr);
 581         if (bytes > bufsize)
 582                 bytes = bufsize;
 583         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 584         return xprt->addrlen;
 585 }
 586 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 587
 588 /**
 589  * rpc_peeraddr2str - return remote peer address in printable format
 590  * @clnt: RPC client structure
 591  * @format: address format
 592  *
 593  */
 594 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 595 {
 596         struct rpc_xprt *xprt = clnt->cl_xprt;
 597
 598         if (xprt->address_strings[format] != NULL)
 599                 return xprt->address_strings[format];
 600         else
 601                 return "unprintable";
 602 }
 603 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 604
 605 void
 606 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 607 {
 608         struct rpc_xprt *xprt = clnt->cl_xprt;
 609         if (xprt->ops->set_buffer_size)
 610                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 611 }
 612
 613 /*
 614  * Return size of largest payload RPC client can support, in bytes
 615  *
 616  * For stream transports, this is one RPC record fragment (see RFC
 617  * 1831), as we don't support multi-record requests yet.  For datagram
 618  * transports, this is the size of an IP packet minus the IP, UDP, and
 619  * RPC header sizes.
 620  */
 621 size_t rpc_max_payload(struct rpc_clnt *clnt)
 622 {
 623         return clnt->cl_xprt->max_payload;
 624 }
 625 EXPORT_SYMBOL_GPL(rpc_max_payload);
 626
 627 /**
 628  * rpc_force_rebind - force transport to check that remote port is unchanged
 629  * @clnt: client to rebind
 630  *
 631  */
 632 void rpc_force_rebind(struct rpc_clnt *clnt)
 633 {
 634         if (clnt->cl_autobind)
 635                 xprt_clear_bound(clnt->cl_xprt);
 636 }
 637 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 638
 639 /*
 640  * Restart an (async) RPC call. Usually called from within the
 641  * exit handler.
 642  */
 643 void
 644 rpc_restart_call(struct rpc_task *task)
 645 {
 646         if (RPC_ASSASSINATED(task))
 647                 return;
 648
 649         task->tk_action = call_start;
 650 }
 651
 652 /*
 653  * 0.  Initial state
 654  *
 655  *     Other FSM states can be visited zero or more times, but
 656  *     this state is visited exactly once for each RPC.
 657  */
 658 static void
 659 call_start(struct rpc_task *task)
 660 {
 661         struct rpc_clnt *clnt = task->tk_client;
 662
 663         dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
 664                         clnt->cl_protname, clnt->cl_vers,
 665                         task->tk_msg.rpc_proc->p_proc,
 666                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 667
 668         /* Increment call count */
 669         task->tk_msg.rpc_proc->p_count++;
 670         clnt->cl_stats->rpccnt++;
 671         task->tk_action = call_reserve;
 672 }
 673
 674 /*
 675  * 1.   Reserve an RPC call slot
 676  */
 677 static void
 678 call_reserve(struct rpc_task *task)
 679 {
 680         dprint_status(task);
 681
 682         if (!rpcauth_uptodatecred(task)) {
 683                 task->tk_action = call_refresh;
 684                 return;
 685         }
 686
 687         task->tk_status  = 0;
 688         task->tk_action  = call_reserveresult;
 689         xprt_reserve(task);
 690 }
 691
 692 /*
 693  * 1b.  Grok the result of xprt_reserve()
 694  */
 695 static void
 696 call_reserveresult(struct rpc_task *task)
 697 {
 698         int status = task->tk_status;
 699
 700         dprint_status(task);
 701
 702         /*
 703          * After a call to xprt_reserve(), we must have either
 704          * a request slot or else an error status.
 705          */
 706         task->tk_status = 0;
 707         if (status >= 0) {
 708                 if (task->tk_rqstp) {
 709                         task->tk_action = call_allocate;
 710                         return;
 711                 }
 712
 713                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 714                                 __FUNCTION__, status);
 715                 rpc_exit(task, -EIO);
 716                 return;
 717         }
 718
 719         /*
 720          * Even though there was an error, we may have acquired
 721          * a request slot somehow.  Make sure not to leak it.
 722          */
 723         if (task->tk_rqstp) {
 724                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 725                                 __FUNCTION__, status);
 726                 xprt_release(task);
 727         }
 728
 729         switch (status) {
 730         case -EAGAIN:   /* woken up; retry */
 731                 task->tk_action = call_reserve;
 732                 return;
 733         case -EIO:      /* probably a shutdown */
 734                 break;
 735         default:
 736                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 737                                 __FUNCTION__, status);
 738                 break;
 739         }
 740         rpc_exit(task, status);
 741 }
 742
 743 /*
 744  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 745  *      (Note: buffer memory is freed in xprt_release).
 746  */
 747 static void
 748 call_allocate(struct rpc_task *task)
 749 {
 750         struct rpc_rqst *req = task->tk_rqstp;
 751         struct rpc_xprt *xprt = task->tk_xprt;
 752         unsigned int    bufsiz;
 753
 754         dprint_status(task);
 755
 756         task->tk_action = call_bind;
 757         if (req->rq_buffer)
 758                 return;
 759
 760         /* FIXME: compute buffer requirements more exactly using
 761          * auth->au_wslack */
 762         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 763
 764         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 765                 return;
 766
 767         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
 768
 769         if (RPC_IS_ASYNC(task) || !signalled()) {
 770                 xprt_release(task);
 771                 task->tk_action = call_reserve;
 772                 rpc_delay(task, HZ>>4);
 773                 return;
 774         }
 775
 776         rpc_exit(task, -ERESTARTSYS);
 777 }
 778
 779 static inline int
 780 rpc_task_need_encode(struct rpc_task *task)
 781 {
 782         return task->tk_rqstp->rq_snd_buf.len == 0;
 783 }
 784
 785 static inline void
 786 rpc_task_force_reencode(struct rpc_task *task)
 787 {
 788         task->tk_rqstp->rq_snd_buf.len = 0;
 789 }
 790
 791 /*
 792  * 3.   Encode arguments of an RPC call
 793  */
 794 static void
 795 call_encode(struct rpc_task *task)
 796 {
 797         struct rpc_rqst *req = task->tk_rqstp;
 798         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 799         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 800         unsigned int    bufsiz;
 801         kxdrproc_t      encode;
 802         __be32          *p;
 803
 804         dprint_status(task);
 805
 806         /* Default buffer setup */
 807         bufsiz = req->rq_bufsize >> 1;
 808         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 809         sndbuf->head[0].iov_len  = bufsiz;
 810         sndbuf->tail[0].iov_len  = 0;
 811         sndbuf->page_len         = 0;
 812         sndbuf->len              = 0;
 813         sndbuf->buflen           = bufsiz;
 814         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 815         rcvbuf->head[0].iov_len  = bufsiz;
 816         rcvbuf->tail[0].iov_len  = 0;
 817         rcvbuf->page_len         = 0;
 818         rcvbuf->len              = 0;
 819         rcvbuf->buflen           = bufsiz;
 820
 821         /* Encode header and provided arguments */
 822         encode = task->tk_msg.rpc_proc->p_encode;
 823         if (!(p = call_header(task))) {
 824                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 825                 rpc_exit(task, -EIO);
 826                 return;
 827         }
 828         if (encode == NULL)
 829                 return;
 830
 831         lock_kernel();
 832         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 833                         task->tk_msg.rpc_argp);
 834         unlock_kernel();
 835         if (task->tk_status == -ENOMEM) {
 836                 /* XXX: Is this sane? */
 837                 rpc_delay(task, 3*HZ);
 838                 task->tk_status = -EAGAIN;
 839         }
 840 }
 841
 842 /*
 843  * 4.   Get the server port number if not yet set
 844  */
 845 static void
 846 call_bind(struct rpc_task *task)
 847 {
 848         struct rpc_xprt *xprt = task->tk_xprt;
 849
 850         dprint_status(task);
 851
 852         task->tk_action = call_connect;
 853         if (!xprt_bound(xprt)) {
 854                 task->tk_action = call_bind_status;
 855                 task->tk_timeout = xprt->bind_timeout;
 856                 xprt->ops->rpcbind(task);
 857         }
 858 }
 859
 860 /*
 861  * 4a.  Sort out bind result
 862  */
 863 static void
 864 call_bind_status(struct rpc_task *task)
 865 {
 866         int status = -EACCES;
 867
 868         if (task->tk_status >= 0) {
 869                 dprint_status(task);
 870                 task->tk_status = 0;
 871                 task->tk_action = call_connect;
 872                 return;
 873         }
 874
 875         switch (task->tk_status) {
 876         case -EACCES:
 877                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
 878                                 "unavailable\n", task->tk_pid);
 879                 rpc_delay(task, 3*HZ);
 880                 goto retry_timeout;
 881         case -ETIMEDOUT:
 882                 dprintk("RPC: %5u rpcbind request timed out\n",
 883                                 task->tk_pid);
 884                 goto retry_timeout;
 885         case -EPFNOSUPPORT:
 886                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
 887                                 task->tk_pid);
 888                 break;
 889         case -EPROTONOSUPPORT:
 890                 dprintk("RPC: %5u remote rpcbind version 2 unavailable\n",
 891                                 task->tk_pid);
 892                 break;
 893         default:
 894                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 895                                 task->tk_pid, -task->tk_status);
 896                 status = -EIO;
 897         }
 898
 899         rpc_exit(task, status);
 900         return;
 901
 902 retry_timeout:
 903         task->tk_action = call_timeout;
 904 }
 905
 906 /*
 907  * 4b.  Connect to the RPC server
 908  */
 909 static void
 910 call_connect(struct rpc_task *task)
 911 {
 912         struct rpc_xprt *xprt = task->tk_xprt;
 913
 914         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
 915                         task->tk_pid, xprt,
 916                         (xprt_connected(xprt) ? "is" : "is not"));
 917
 918         task->tk_action = call_transmit;
 919         if (!xprt_connected(xprt)) {
 920                 task->tk_action = call_connect_status;
 921                 if (task->tk_status < 0)
 922                         return;
 923                 xprt_connect(task);
 924         }
 925 }
 926
 927 /*
 928  * 4c.  Sort out connect result
 929  */
 930 static void
 931 call_connect_status(struct rpc_task *task)
 932 {
 933         struct rpc_clnt *clnt = task->tk_client;
 934         int status = task->tk_status;
 935
 936         dprint_status(task);
 937
 938         task->tk_status = 0;
 939         if (status >= 0) {
 940                 clnt->cl_stats->netreconn++;
 941                 task->tk_action = call_transmit;
 942                 return;
 943         }
 944
 945         /* Something failed: remote service port may have changed */
 946         rpc_force_rebind(clnt);
 947
 948         switch (status) {
 949         case -ENOTCONN:
 950         case -EAGAIN:
 951                 task->tk_action = call_bind;
 952                 if (!RPC_IS_SOFT(task))
 953                         return;
 954                 /* if soft mounted, test if we've timed out */
 955         case -ETIMEDOUT:
 956                 task->tk_action = call_timeout;
 957                 return;
 958         }
 959         rpc_exit(task, -EIO);
 960 }
 961
 962 /*
 963  * 5.   Transmit the RPC request, and wait for reply
 964  */
 965 static void
 966 call_transmit(struct rpc_task *task)
 967 {
 968         dprint_status(task);
 969
 970         task->tk_action = call_status;
 971         if (task->tk_status < 0)
 972                 return;
 973         task->tk_status = xprt_prepare_transmit(task);
 974         if (task->tk_status != 0)
 975                 return;
 976         task->tk_action = call_transmit_status;
 977         /* Encode here so that rpcsec_gss can use correct sequence number. */
 978         if (rpc_task_need_encode(task)) {
 979                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 980                 call_encode(task);
 981                 /* Did the encode result in an error condition? */
 982                 if (task->tk_status != 0)
 983                         return;
 984         }
 985         xprt_transmit(task);
 986         if (task->tk_status < 0)
 987                 return;
 988         /*
 989          * On success, ensure that we call xprt_end_transmit() before sleeping
 990          * in order to allow access to the socket to other RPC requests.
 991          */
 992         call_transmit_status(task);
 993         if (task->tk_msg.rpc_proc->p_decode != NULL)
 994                 return;
 995         task->tk_action = rpc_exit_task;
 996         rpc_wake_up_task(task);
 997 }
 998
 999 /*
1000  * 5a.  Handle cleanup after a transmission
1001  */
1002 static void
1003 call_transmit_status(struct rpc_task *task)
1004 {
1005         task->tk_action = call_status;
1006         /*
1007          * Special case: if we've been waiting on the socket's write_space()
1008          * callback, then don't call xprt_end_transmit().
1009          */
1010         if (task->tk_status == -EAGAIN)
1011                 return;
1012         xprt_end_transmit(task);
1013         rpc_task_force_reencode(task);
1014 }
1015
1016 /*
1017  * 6.   Sort out the RPC call status
1018  */
1019 static void
1020 call_status(struct rpc_task *task)
1021 {
1022         struct rpc_clnt *clnt = task->tk_client;
1023         struct rpc_rqst *req = task->tk_rqstp;
1024         int             status;
1025
1026         if (req->rq_received > 0 && !req->rq_bytes_sent)
1027                 task->tk_status = req->rq_received;
1028
1029         dprint_status(task);
1030
1031         status = task->tk_status;
1032         if (status >= 0) {
1033                 task->tk_action = call_decode;
1034                 return;
1035         }
1036
1037         task->tk_status = 0;
1038         switch(status) {
1039         case -EHOSTDOWN:
1040         case -EHOSTUNREACH:
1041         case -ENETUNREACH:
1042                 /*
1043                  * Delay any retries for 3 seconds, then handle as if it
1044                  * were a timeout.
1045                  */
1046                 rpc_delay(task, 3*HZ);
1047         case -ETIMEDOUT:
1048                 task->tk_action = call_timeout;
1049                 break;
1050         case -ECONNREFUSED:
1051         case -ENOTCONN:
1052                 rpc_force_rebind(clnt);
1053                 task->tk_action = call_bind;
1054                 break;
1055         case -EAGAIN:
1056                 task->tk_action = call_transmit;
1057                 break;
1058         case -EIO:
1059                 /* shutdown or soft timeout */
1060                 rpc_exit(task, status);
1061                 break;
1062         default:
1063                 printk("%s: RPC call returned error %d\n",
1064                                clnt->cl_protname, -status);
1065                 rpc_exit(task, status);
1066         }
1067 }
1068
1069 /*
1070  * 6a.  Handle RPC timeout
1071  *      We do not release the request slot, so we keep using the
1072  *      same XID for all retransmits.
1073  */
1074 static void
1075 call_timeout(struct rpc_task *task)
1076 {
1077         struct rpc_clnt *clnt = task->tk_client;
1078
1079         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1080                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1081                 goto retry;
1082         }
1083
1084         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1085         task->tk_timeouts++;
1086
1087         if (RPC_IS_SOFT(task)) {
1088                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1089                                 clnt->cl_protname, clnt->cl_server);
1090                 rpc_exit(task, -EIO);
1091                 return;
1092         }
1093
1094         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1095                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1096                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1097                         clnt->cl_protname, clnt->cl_server);
1098         }
1099         rpc_force_rebind(clnt);
1100
1101 retry:
1102         clnt->cl_stats->rpcretrans++;
1103         task->tk_action = call_bind;
1104         task->tk_status = 0;
1105 }
1106
1107 /*
1108  * 7.   Decode the RPC reply
1109  */
1110 static void
1111 call_decode(struct rpc_task *task)
1112 {
1113         struct rpc_clnt *clnt = task->tk_client;
1114         struct rpc_rqst *req = task->tk_rqstp;
1115         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1116         __be32          *p;
1117
1118         dprintk("RPC: %5u call_decode (status %d)\n",
1119                         task->tk_pid, task->tk_status);
1120
1121         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1122                 printk(KERN_NOTICE "%s: server %s OK\n",
1123                         clnt->cl_protname, clnt->cl_server);
1124                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1125         }
1126
1127         if (task->tk_status < 12) {
1128                 if (!RPC_IS_SOFT(task)) {
1129                         task->tk_action = call_bind;
1130                         clnt->cl_stats->rpcretrans++;
1131                         goto out_retry;
1132                 }
1133                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1134                                 clnt->cl_protname, task->tk_status);
1135                 task->tk_action = call_timeout;
1136                 goto out_retry;
1137         }
1138
1139         /*
1140          * Ensure that we see all writes made by xprt_complete_rqst()
1141          * before it changed req->rq_received.
1142          */
1143         smp_rmb();
1144         req->rq_rcv_buf.len = req->rq_private_buf.len;
1145
1146         /* Check that the softirq receive buffer is valid */
1147         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1148                                 sizeof(req->rq_rcv_buf)) != 0);
1149
1150         /* Verify the RPC header */
1151         p = call_verify(task);
1152         if (IS_ERR(p)) {
1153                 if (p == ERR_PTR(-EAGAIN))
1154                         goto out_retry;
1155                 return;
1156         }
1157
1158         task->tk_action = rpc_exit_task;
1159
1160         if (decode) {
1161                 lock_kernel();
1162                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1163                                                       task->tk_msg.rpc_resp);
1164                 unlock_kernel();
1165         }
1166         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1167                         task->tk_status);
1168         return;
1169 out_retry:
1170         req->rq_received = req->rq_private_buf.len = 0;
1171         task->tk_status = 0;
1172 }
1173
1174 /*
1175  * 8.   Refresh the credentials if rejected by the server
1176  */
1177 static void
1178 call_refresh(struct rpc_task *task)
1179 {
1180         dprint_status(task);
1181
1182         xprt_release(task);     /* Must do to obtain new XID */
1183         task->tk_action = call_refreshresult;
1184         task->tk_status = 0;
1185         task->tk_client->cl_stats->rpcauthrefresh++;
1186         rpcauth_refreshcred(task);
1187 }
1188
1189 /*
1190  * 8a.  Process the results of a credential refresh
1191  */
1192 static void
1193 call_refreshresult(struct rpc_task *task)
1194 {
1195         int status = task->tk_status;
1196
1197         dprint_status(task);
1198
1199         task->tk_status = 0;
1200         task->tk_action = call_reserve;
1201         if (status >= 0 && rpcauth_uptodatecred(task))
1202                 return;
1203         if (status == -EACCES) {
1204                 rpc_exit(task, -EACCES);
1205                 return;
1206         }
1207         task->tk_action = call_refresh;
1208         if (status != -ETIMEDOUT)
1209                 rpc_delay(task, 3*HZ);
1210         return;
1211 }
1212
1213 /*
1214  * Call header serialization
1215  */
1216 static __be32 *
1217 call_header(struct rpc_task *task)
1218 {
1219         struct rpc_clnt *clnt = task->tk_client;
1220         struct rpc_rqst *req = task->tk_rqstp;
1221         __be32          *p = req->rq_svec[0].iov_base;
1222
1223         /* FIXME: check buffer size? */
1224
1225         p = xprt_skip_transport_header(task->tk_xprt, p);
1226         *p++ = req->rq_xid;             /* XID */
1227         *p++ = htonl(RPC_CALL);         /* CALL */
1228         *p++ = htonl(RPC_VERSION);      /* RPC version */
1229         *p++ = htonl(clnt->cl_prog);    /* program number */
1230         *p++ = htonl(clnt->cl_vers);    /* program version */
1231         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1232         p = rpcauth_marshcred(task, p);
1233         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1234         return p;
1235 }
1236
1237 /*
1238  * Reply header verification
1239  */
1240 static __be32 *
1241 call_verify(struct rpc_task *task)
1242 {
1243         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1244         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1245         __be32  *p = iov->iov_base;
1246         u32 n;
1247         int error = -EACCES;
1248
1249         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1250                 /* RFC-1014 says that the representation of XDR data must be a
1251                  * multiple of four bytes
1252                  * - if it isn't pointer subtraction in the NFS client may give
1253                  *   undefined results
1254                  */
1255                 printk(KERN_WARNING
1256                        "call_verify: XDR representation not a multiple of"
1257                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1258                 goto out_eio;
1259         }
1260         if ((len -= 3) < 0)
1261                 goto out_overflow;
1262         p += 1; /* skip XID */
1263
1264         if ((n = ntohl(*p++)) != RPC_REPLY) {
1265                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1266                 goto out_garbage;
1267         }
1268         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1269                 if (--len < 0)
1270                         goto out_overflow;
1271                 switch ((n = ntohl(*p++))) {
1272                         case RPC_AUTH_ERROR:
1273                                 break;
1274                         case RPC_MISMATCH:
1275                                 dprintk("RPC: %5u %s: RPC call version "
1276                                                 "mismatch!\n",
1277                                                 task->tk_pid, __FUNCTION__);
1278                                 error = -EPROTONOSUPPORT;
1279                                 goto out_err;
1280                         default:
1281                                 dprintk("RPC: %5u %s: RPC call rejected, "
1282                                                 "unknown error: %x\n",
1283                                                 task->tk_pid, __FUNCTION__, n);
1284                                 goto out_eio;
1285                 }
1286                 if (--len < 0)
1287                         goto out_overflow;
1288                 switch ((n = ntohl(*p++))) {
1289                 case RPC_AUTH_REJECTEDCRED:
1290                 case RPC_AUTH_REJECTEDVERF:
1291                 case RPCSEC_GSS_CREDPROBLEM:
1292                 case RPCSEC_GSS_CTXPROBLEM:
1293                         if (!task->tk_cred_retry)
1294                                 break;
1295                         task->tk_cred_retry--;
1296                         dprintk("RPC: %5u %s: retry stale creds\n",
1297                                         task->tk_pid, __FUNCTION__);
1298                         rpcauth_invalcred(task);
1299                         task->tk_action = call_refresh;
1300                         goto out_retry;
1301                 case RPC_AUTH_BADCRED:
1302                 case RPC_AUTH_BADVERF:
1303                         /* possibly garbled cred/verf? */
1304                         if (!task->tk_garb_retry)
1305                                 break;
1306                         task->tk_garb_retry--;
1307                         dprintk("RPC: %5u %s: retry garbled creds\n",
1308                                         task->tk_pid, __FUNCTION__);
1309                         task->tk_action = call_bind;
1310                         goto out_retry;
1311                 case RPC_AUTH_TOOWEAK:
1312                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1313                                "authentication.\n", task->tk_client->cl_server);
1314                         break;
1315                 default:
1316                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1317                         error = -EIO;
1318                 }
1319                 dprintk("RPC: %5u %s: call rejected %d\n",
1320                                 task->tk_pid, __FUNCTION__, n);
1321                 goto out_err;
1322         }
1323         if (!(p = rpcauth_checkverf(task, p))) {
1324                 printk(KERN_WARNING "call_verify: auth check failed\n");
1325                 goto out_garbage;               /* bad verifier, retry */
1326         }
1327         len = p - (__be32 *)iov->iov_base - 1;
1328         if (len < 0)
1329                 goto out_overflow;
1330         switch ((n = ntohl(*p++))) {
1331         case RPC_SUCCESS:
1332                 return p;
1333         case RPC_PROG_UNAVAIL:
1334                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1335                                 task->tk_pid, __FUNCTION__,
1336                                 (unsigned int)task->tk_client->cl_prog,
1337                                 task->tk_client->cl_server);
1338                 error = -EPFNOSUPPORT;
1339                 goto out_err;
1340         case RPC_PROG_MISMATCH:
1341                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1342                                 "server %s\n", task->tk_pid, __FUNCTION__,
1343                                 (unsigned int)task->tk_client->cl_prog,
1344                                 (unsigned int)task->tk_client->cl_vers,
1345                                 task->tk_client->cl_server);
1346                 error = -EPROTONOSUPPORT;
1347                 goto out_err;
1348         case RPC_PROC_UNAVAIL:
1349                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1350                                 "version %u on server %s\n",
1351                                 task->tk_pid, __FUNCTION__,
1352                                 task->tk_msg.rpc_proc,
1353                                 task->tk_client->cl_prog,
1354                                 task->tk_client->cl_vers,
1355                                 task->tk_client->cl_server);
1356                 error = -EOPNOTSUPP;
1357                 goto out_err;
1358         case RPC_GARBAGE_ARGS:
1359                 dprintk("RPC: %5u %s: server saw garbage\n",
1360                                 task->tk_pid, __FUNCTION__);
1361                 break;                  /* retry */
1362         default:
1363                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1364                 /* Also retry */
1365         }
1366
1367 out_garbage:
1368         task->tk_client->cl_stats->rpcgarbage++;
1369         if (task->tk_garb_retry) {
1370                 task->tk_garb_retry--;
1371                 dprintk("RPC: %5u %s: retrying\n",
1372                                 task->tk_pid, __FUNCTION__);
1373                 task->tk_action = call_bind;
1374 out_retry:
1375                 return ERR_PTR(-EAGAIN);
1376         }
1377         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1378 out_eio:
1379         error = -EIO;
1380 out_err:
1381         rpc_exit(task, error);
1382         return ERR_PTR(error);
1383 out_overflow:
1384         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1385         goto out_garbage;
1386 }
1387
1388 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1389 {
1390         return 0;
1391 }
1392
1393 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1394 {
1395         return 0;
1396 }
1397
1398 static struct rpc_procinfo rpcproc_null = {
1399         .p_encode = rpcproc_encode_null,
1400         .p_decode = rpcproc_decode_null,
1401 };
1402
1403 int rpc_ping(struct rpc_clnt *clnt, int flags)
1404 {
1405         struct rpc_message msg = {
1406                 .rpc_proc = &rpcproc_null,
1407         };
1408         int err;
1409         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1410         err = rpc_call_sync(clnt, &msg, flags);
1411         put_rpccred(msg.rpc_cred);
1412         return err;
1413 }