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 #include <linux/in6.h>
  34
  35 #include <linux/sunrpc/clnt.h>
  36 #include <linux/sunrpc/rpc_pipe_fs.h>
  37 #include <linux/sunrpc/metrics.h>
  38
  39
  40 #ifdef RPC_DEBUG
  41 # define RPCDBG_FACILITY        RPCDBG_CALL
  42 #endif
  43
  44 #define dprint_status(t)                                        \
  45         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  46                         __func__, t->tk_status)
  47
  48 /*
  49  * All RPC clients are linked into this list
  50  */
  51 static LIST_HEAD(all_clients);
  52 static DEFINE_SPINLOCK(rpc_client_lock);
  53
  54 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  55
  56
  57 static void     call_start(struct rpc_task *task);
  58 static void     call_reserve(struct rpc_task *task);
  59 static void     call_reserveresult(struct rpc_task *task);
  60 static void     call_allocate(struct rpc_task *task);
  61 static void     call_encode(struct rpc_task *task);
  62 static void     call_decode(struct rpc_task *task);
  63 static void     call_bind(struct rpc_task *task);
  64 static void     call_bind_status(struct rpc_task *task);
  65 static void     call_transmit(struct rpc_task *task);
  66 static void     call_status(struct rpc_task *task);
  67 static void     call_transmit_status(struct rpc_task *task);
  68 static void     call_refresh(struct rpc_task *task);
  69 static void     call_refreshresult(struct rpc_task *task);
  70 static void     call_timeout(struct rpc_task *task);
  71 static void     call_connect(struct rpc_task *task);
  72 static void     call_connect_status(struct rpc_task *task);
  73 static __be32 * call_header(struct rpc_task *task);
  74 static __be32 * call_verify(struct rpc_task *task);
  75
  76 static int      rpc_ping(struct rpc_clnt *clnt, int flags);
  77
  78 static void rpc_register_client(struct rpc_clnt *clnt)
  79 {
  80         spin_lock(&rpc_client_lock);
  81         list_add(&clnt->cl_clients, &all_clients);
  82         spin_unlock(&rpc_client_lock);
  83 }
  84
  85 static void rpc_unregister_client(struct rpc_clnt *clnt)
  86 {
  87         spin_lock(&rpc_client_lock);
  88         list_del(&clnt->cl_clients);
  89         spin_unlock(&rpc_client_lock);
  90 }
  91
  92 static int
  93 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  94 {
  95         static uint32_t clntid;
  96         int error;
  97
  98         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  99         clnt->cl_dentry = ERR_PTR(-ENOENT);
 100         if (dir_name == NULL)
 101                 return 0;
 102
 103         clnt->cl_vfsmnt = rpc_get_mount();
 104         if (IS_ERR(clnt->cl_vfsmnt))
 105                 return PTR_ERR(clnt->cl_vfsmnt);
 106
 107         for (;;) {
 108                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
 109                                 "%s/clnt%x", dir_name,
 110                                 (unsigned int)clntid++);
 111                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
 112                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
 113                 if (!IS_ERR(clnt->cl_dentry))
 114                         return 0;
 115                 error = PTR_ERR(clnt->cl_dentry);
 116                 if (error != -EEXIST) {
 117                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
 118                                         clnt->cl_pathname, error);
 119                         rpc_put_mount();
 120                         return error;
 121                 }
 122         }
 123 }
 124
 125 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
 126 {
 127         struct rpc_program      *program = args->program;
 128         struct rpc_version      *version;
 129         struct rpc_clnt         *clnt = NULL;
 130         struct rpc_auth         *auth;
 131         int err;
 132         size_t len;
 133
 134         /* sanity check the name before trying to print it */
 135         err = -EINVAL;
 136         len = strlen(args->servername);
 137         if (len > RPC_MAXNETNAMELEN)
 138                 goto out_no_rpciod;
 139         len++;
 140
 141         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 142                         program->name, args->servername, xprt);
 143
 144         err = rpciod_up();
 145         if (err)
 146                 goto out_no_rpciod;
 147         err = -EINVAL;
 148         if (!xprt)
 149                 goto out_no_xprt;
 150
 151         if (args->version >= program->nrvers)
 152                 goto out_err;
 153         version = program->version[args->version];
 154         if (version == NULL)
 155                 goto out_err;
 156
 157         err = -ENOMEM;
 158         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 159         if (!clnt)
 160                 goto out_err;
 161         clnt->cl_parent = clnt;
 162
 163         clnt->cl_server = clnt->cl_inline_name;
 164         if (len > sizeof(clnt->cl_inline_name)) {
 165                 char *buf = kmalloc(len, GFP_KERNEL);
 166                 if (buf != NULL)
 167                         clnt->cl_server = buf;
 168                 else
 169                         len = sizeof(clnt->cl_inline_name);
 170         }
 171         strlcpy(clnt->cl_server, args->servername, len);
 172
 173         clnt->cl_xprt     = xprt;
 174         clnt->cl_procinfo = version->procs;
 175         clnt->cl_maxproc  = version->nrprocs;
 176         clnt->cl_protname = program->name;
 177         clnt->cl_prog     = program->number;
 178         clnt->cl_vers     = version->number;
 179         clnt->cl_stats    = program->stats;
 180         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 181         err = -ENOMEM;
 182         if (clnt->cl_metrics == NULL)
 183                 goto out_no_stats;
 184         clnt->cl_program  = program;
 185         INIT_LIST_HEAD(&clnt->cl_tasks);
 186         spin_lock_init(&clnt->cl_lock);
 187
 188         if (!xprt_bound(clnt->cl_xprt))
 189                 clnt->cl_autobind = 1;
 190
 191         clnt->cl_timeout = xprt->timeout;
 192         if (args->timeout != NULL) {
 193                 memcpy(&clnt->cl_timeout_default, args->timeout,
 194                                 sizeof(clnt->cl_timeout_default));
 195                 clnt->cl_timeout = &clnt->cl_timeout_default;
 196         }
 197
 198         clnt->cl_rtt = &clnt->cl_rtt_default;
 199         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
 200
 201         kref_init(&clnt->cl_kref);
 202
 203         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 204         if (err < 0)
 205                 goto out_no_path;
 206
 207         auth = rpcauth_create(args->authflavor, clnt);
 208         if (IS_ERR(auth)) {
 209                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 210                                 args->authflavor);
 211                 err = PTR_ERR(auth);
 212                 goto out_no_auth;
 213         }
 214
 215         /* save the nodename */
 216         clnt->cl_nodelen = strlen(utsname()->nodename);
 217         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 218                 clnt->cl_nodelen = UNX_MAXNODENAME;
 219         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 220         rpc_register_client(clnt);
 221         return clnt;
 222
 223 out_no_auth:
 224         if (!IS_ERR(clnt->cl_dentry)) {
 225                 rpc_rmdir(clnt->cl_dentry);
 226                 rpc_put_mount();
 227         }
 228 out_no_path:
 229         rpc_free_iostats(clnt->cl_metrics);
 230 out_no_stats:
 231         if (clnt->cl_server != clnt->cl_inline_name)
 232                 kfree(clnt->cl_server);
 233         kfree(clnt);
 234 out_err:
 235         xprt_put(xprt);
 236 out_no_xprt:
 237         rpciod_down();
 238 out_no_rpciod:
 239         return ERR_PTR(err);
 240 }
 241
 242 /*
 243  * rpc_create - create an RPC client and transport with one call
 244  * @args: rpc_clnt create argument structure
 245  *
 246  * Creates and initializes an RPC transport and an RPC client.
 247  *
 248  * It can ping the server in order to determine if it is up, and to see if
 249  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 250  * this behavior so asynchronous tasks can also use rpc_create.
 251  */
 252 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 253 {
 254         struct rpc_xprt *xprt;
 255         struct rpc_clnt *clnt;
 256         struct xprt_create xprtargs = {
 257                 .ident = args->protocol,
 258                 .srcaddr = args->saddress,
 259                 .dstaddr = args->address,
 260                 .addrlen = args->addrsize,
 261         };
 262         char servername[48];
 263
 264         /*
 265          * If the caller chooses not to specify a hostname, whip
 266          * up a string representation of the passed-in address.
 267          */
 268         if (args->servername == NULL) {
 269                 servername[0] = '\0';
 270                 switch (args->address->sa_family) {
 271                 case AF_INET: {
 272                         struct sockaddr_in *sin =
 273                                         (struct sockaddr_in *)args->address;
 274                         snprintf(servername, sizeof(servername), NIPQUAD_FMT,
 275                                  NIPQUAD(sin->sin_addr.s_addr));
 276                         break;
 277                 }
 278                 case AF_INET6: {
 279                         struct sockaddr_in6 *sin =
 280                                         (struct sockaddr_in6 *)args->address;
 281                         snprintf(servername, sizeof(servername), NIP6_FMT,
 282                                  NIP6(sin->sin6_addr));
 283                         break;
 284                 }
 285                 default:
 286                         /* caller wants default server name, but
 287                          * address family isn't recognized. */
 288                         return ERR_PTR(-EINVAL);
 289                 }
 290                 args->servername = servername;
 291         }
 292
 293         xprt = xprt_create_transport(&xprtargs);
 294         if (IS_ERR(xprt))
 295                 return (struct rpc_clnt *)xprt;
 296
 297         /*
 298          * By default, kernel RPC client connects from a reserved port.
 299          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 300          * but it is always enabled for rpciod, which handles the connect
 301          * operation.
 302          */
 303         xprt->resvport = 1;
 304         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 305                 xprt->resvport = 0;
 306
 307         clnt = rpc_new_client(args, xprt);
 308         if (IS_ERR(clnt))
 309                 return clnt;
 310
 311         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 312                 int err = rpc_ping(clnt, RPC_TASK_SOFT);
 313                 if (err != 0) {
 314                         rpc_shutdown_client(clnt);
 315                         return ERR_PTR(err);
 316                 }
 317         }
 318
 319         clnt->cl_softrtry = 1;
 320         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 321                 clnt->cl_softrtry = 0;
 322
 323         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 324                 clnt->cl_autobind = 1;
 325         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 326                 clnt->cl_discrtry = 1;
 327
 328         return clnt;
 329 }
 330 EXPORT_SYMBOL_GPL(rpc_create);
 331
 332 /*
 333  * This function clones the RPC client structure. It allows us to share the
 334  * same transport while varying parameters such as the authentication
 335  * flavour.
 336  */
 337 struct rpc_clnt *
 338 rpc_clone_client(struct rpc_clnt *clnt)
 339 {
 340         struct rpc_clnt *new;
 341         int err = -ENOMEM;
 342
 343         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 344         if (!new)
 345                 goto out_no_clnt;
 346         new->cl_parent = clnt;
 347         /* Turn off autobind on clones */
 348         new->cl_autobind = 0;
 349         INIT_LIST_HEAD(&new->cl_tasks);
 350         spin_lock_init(&new->cl_lock);
 351         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_timeout->to_initval);
 352         new->cl_metrics = rpc_alloc_iostats(clnt);
 353         if (new->cl_metrics == NULL)
 354                 goto out_no_stats;
 355         kref_init(&new->cl_kref);
 356         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 357         if (err != 0)
 358                 goto out_no_path;
 359         if (new->cl_auth)
 360                 atomic_inc(&new->cl_auth->au_count);
 361         xprt_get(clnt->cl_xprt);
 362         kref_get(&clnt->cl_kref);
 363         rpc_register_client(new);
 364         rpciod_up();
 365         return new;
 366 out_no_path:
 367         rpc_free_iostats(new->cl_metrics);
 368 out_no_stats:
 369         kfree(new);
 370 out_no_clnt:
 371         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 372         return ERR_PTR(err);
 373 }
 374 EXPORT_SYMBOL_GPL(rpc_clone_client);
 375
 376 /*
 377  * Properly shut down an RPC client, terminating all outstanding
 378  * requests.
 379  */
 380 void rpc_shutdown_client(struct rpc_clnt *clnt)
 381 {
 382         dprintk("RPC:       shutting down %s client for %s\n",
 383                         clnt->cl_protname, clnt->cl_server);
 384
 385         while (!list_empty(&clnt->cl_tasks)) {
 386                 rpc_killall_tasks(clnt);
 387                 wait_event_timeout(destroy_wait,
 388                         list_empty(&clnt->cl_tasks), 1*HZ);
 389         }
 390
 391         rpc_release_client(clnt);
 392 }
 393 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 394
 395 /*
 396  * Free an RPC client
 397  */
 398 static void
 399 rpc_free_client(struct kref *kref)
 400 {
 401         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 402
 403         dprintk("RPC:       destroying %s client for %s\n",
 404                         clnt->cl_protname, clnt->cl_server);
 405         if (!IS_ERR(clnt->cl_dentry)) {
 406                 rpc_rmdir(clnt->cl_dentry);
 407                 rpc_put_mount();
 408         }
 409         if (clnt->cl_parent != clnt) {
 410                 rpc_release_client(clnt->cl_parent);
 411                 goto out_free;
 412         }
 413         if (clnt->cl_server != clnt->cl_inline_name)
 414                 kfree(clnt->cl_server);
 415 out_free:
 416         rpc_unregister_client(clnt);
 417         rpc_free_iostats(clnt->cl_metrics);
 418         clnt->cl_metrics = NULL;
 419         xprt_put(clnt->cl_xprt);
 420         rpciod_down();
 421         kfree(clnt);
 422 }
 423
 424 /*
 425  * Free an RPC client
 426  */
 427 static void
 428 rpc_free_auth(struct kref *kref)
 429 {
 430         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 431
 432         if (clnt->cl_auth == NULL) {
 433                 rpc_free_client(kref);
 434                 return;
 435         }
 436
 437         /*
 438          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 439          *       release remaining GSS contexts. This mechanism ensures
 440          *       that it can do so safely.
 441          */
 442         kref_init(kref);
 443         rpcauth_release(clnt->cl_auth);
 444         clnt->cl_auth = NULL;
 445         kref_put(kref, rpc_free_client);
 446 }
 447
 448 /*
 449  * Release reference to the RPC client
 450  */
 451 void
 452 rpc_release_client(struct rpc_clnt *clnt)
 453 {
 454         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 455
 456         if (list_empty(&clnt->cl_tasks))
 457                 wake_up(&destroy_wait);
 458         kref_put(&clnt->cl_kref, rpc_free_auth);
 459 }
 460
 461 /**
 462  * rpc_bind_new_program - bind a new RPC program to an existing client
 463  * @old: old rpc_client
 464  * @program: rpc program to set
 465  * @vers: rpc program version
 466  *
 467  * Clones the rpc client and sets up a new RPC program. This is mainly
 468  * of use for enabling different RPC programs to share the same transport.
 469  * The Sun NFSv2/v3 ACL protocol can do this.
 470  */
 471 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 472                                       struct rpc_program *program,
 473                                       u32 vers)
 474 {
 475         struct rpc_clnt *clnt;
 476         struct rpc_version *version;
 477         int err;
 478
 479         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 480         version = program->version[vers];
 481         clnt = rpc_clone_client(old);
 482         if (IS_ERR(clnt))
 483                 goto out;
 484         clnt->cl_procinfo = version->procs;
 485         clnt->cl_maxproc  = version->nrprocs;
 486         clnt->cl_protname = program->name;
 487         clnt->cl_prog     = program->number;
 488         clnt->cl_vers     = version->number;
 489         clnt->cl_stats    = program->stats;
 490         err = rpc_ping(clnt, RPC_TASK_SOFT);
 491         if (err != 0) {
 492                 rpc_shutdown_client(clnt);
 493                 clnt = ERR_PTR(err);
 494         }
 495 out:
 496         return clnt;
 497 }
 498 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 499
 500 /*
 501  * Default callback for async RPC calls
 502  */
 503 static void
 504 rpc_default_callback(struct rpc_task *task, void *data)
 505 {
 506 }
 507
 508 static const struct rpc_call_ops rpc_default_ops = {
 509         .rpc_call_done = rpc_default_callback,
 510 };
 511
 512 /**
 513  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 514  * @task_setup_data: pointer to task initialisation data
 515  */
 516 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 517 {
 518         struct rpc_task *task, *ret;
 519
 520         task = rpc_new_task(task_setup_data);
 521         if (task == NULL) {
 522                 rpc_release_calldata(task_setup_data->callback_ops,
 523                                 task_setup_data->callback_data);
 524                 ret = ERR_PTR(-ENOMEM);
 525                 goto out;
 526         }
 527
 528         if (task->tk_status != 0) {
 529                 ret = ERR_PTR(task->tk_status);
 530                 rpc_put_task(task);
 531                 goto out;
 532         }
 533         atomic_inc(&task->tk_count);
 534         rpc_execute(task);
 535         ret = task;
 536 out:
 537         return ret;
 538 }
 539 EXPORT_SYMBOL_GPL(rpc_run_task);
 540
 541 /**
 542  * rpc_call_sync - Perform a synchronous RPC call
 543  * @clnt: pointer to RPC client
 544  * @msg: RPC call parameters
 545  * @flags: RPC call flags
 546  */
 547 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 548 {
 549         struct rpc_task *task;
 550         struct rpc_task_setup task_setup_data = {
 551                 .rpc_client = clnt,
 552                 .rpc_message = msg,
 553                 .callback_ops = &rpc_default_ops,
 554                 .flags = flags,
 555         };
 556         int status;
 557
 558         BUG_ON(flags & RPC_TASK_ASYNC);
 559
 560         task = rpc_run_task(&task_setup_data);
 561         if (IS_ERR(task))
 562                 return PTR_ERR(task);
 563         status = task->tk_status;
 564         rpc_put_task(task);
 565         return status;
 566 }
 567 EXPORT_SYMBOL_GPL(rpc_call_sync);
 568
 569 /**
 570  * rpc_call_async - Perform an asynchronous RPC call
 571  * @clnt: pointer to RPC client
 572  * @msg: RPC call parameters
 573  * @flags: RPC call flags
 574  * @tk_ops: RPC call ops
 575  * @data: user call data
 576  */
 577 int
 578 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
 579                const struct rpc_call_ops *tk_ops, void *data)
 580 {
 581         struct rpc_task *task;
 582         struct rpc_task_setup task_setup_data = {
 583                 .rpc_client = clnt,
 584                 .rpc_message = msg,
 585                 .callback_ops = tk_ops,
 586                 .callback_data = data,
 587                 .flags = flags|RPC_TASK_ASYNC,
 588         };
 589
 590         task = rpc_run_task(&task_setup_data);
 591         if (IS_ERR(task))
 592                 return PTR_ERR(task);
 593         rpc_put_task(task);
 594         return 0;
 595 }
 596 EXPORT_SYMBOL_GPL(rpc_call_async);
 597
 598 void
 599 rpc_call_start(struct rpc_task *task)
 600 {
 601         task->tk_action = call_start;
 602 }
 603 EXPORT_SYMBOL_GPL(rpc_call_start);
 604
 605 /**
 606  * rpc_peeraddr - extract remote peer address from clnt's xprt
 607  * @clnt: RPC client structure
 608  * @buf: target buffer
 609  * @bufsize: length of target buffer
 610  *
 611  * Returns the number of bytes that are actually in the stored address.
 612  */
 613 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 614 {
 615         size_t bytes;
 616         struct rpc_xprt *xprt = clnt->cl_xprt;
 617
 618         bytes = sizeof(xprt->addr);
 619         if (bytes > bufsize)
 620                 bytes = bufsize;
 621         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 622         return xprt->addrlen;
 623 }
 624 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 625
 626 /**
 627  * rpc_peeraddr2str - return remote peer address in printable format
 628  * @clnt: RPC client structure
 629  * @format: address format
 630  *
 631  */
 632 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
 633                              enum rpc_display_format_t format)
 634 {
 635         struct rpc_xprt *xprt = clnt->cl_xprt;
 636
 637         if (xprt->address_strings[format] != NULL)
 638                 return xprt->address_strings[format];
 639         else
 640                 return "unprintable";
 641 }
 642 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 643
 644 void
 645 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 646 {
 647         struct rpc_xprt *xprt = clnt->cl_xprt;
 648         if (xprt->ops->set_buffer_size)
 649                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 650 }
 651 EXPORT_SYMBOL_GPL(rpc_setbufsize);
 652
 653 /*
 654  * Return size of largest payload RPC client can support, in bytes
 655  *
 656  * For stream transports, this is one RPC record fragment (see RFC
 657  * 1831), as we don't support multi-record requests yet.  For datagram
 658  * transports, this is the size of an IP packet minus the IP, UDP, and
 659  * RPC header sizes.
 660  */
 661 size_t rpc_max_payload(struct rpc_clnt *clnt)
 662 {
 663         return clnt->cl_xprt->max_payload;
 664 }
 665 EXPORT_SYMBOL_GPL(rpc_max_payload);
 666
 667 /**
 668  * rpc_force_rebind - force transport to check that remote port is unchanged
 669  * @clnt: client to rebind
 670  *
 671  */
 672 void rpc_force_rebind(struct rpc_clnt *clnt)
 673 {
 674         if (clnt->cl_autobind)
 675                 xprt_clear_bound(clnt->cl_xprt);
 676 }
 677 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 678
 679 /*
 680  * Restart an (async) RPC call. Usually called from within the
 681  * exit handler.
 682  */
 683 void
 684 rpc_restart_call(struct rpc_task *task)
 685 {
 686         if (RPC_ASSASSINATED(task))
 687                 return;
 688
 689         task->tk_action = call_start;
 690 }
 691 EXPORT_SYMBOL_GPL(rpc_restart_call);
 692
 693 /*
 694  * 0.  Initial state
 695  *
 696  *     Other FSM states can be visited zero or more times, but
 697  *     this state is visited exactly once for each RPC.
 698  */
 699 static void
 700 call_start(struct rpc_task *task)
 701 {
 702         struct rpc_clnt *clnt = task->tk_client;
 703
 704         dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
 705                         clnt->cl_protname, clnt->cl_vers,
 706                         task->tk_msg.rpc_proc->p_proc,
 707                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 708
 709         /* Increment call count */
 710         task->tk_msg.rpc_proc->p_count++;
 711         clnt->cl_stats->rpccnt++;
 712         task->tk_action = call_reserve;
 713 }
 714
 715 /*
 716  * 1.   Reserve an RPC call slot
 717  */
 718 static void
 719 call_reserve(struct rpc_task *task)
 720 {
 721         dprint_status(task);
 722
 723         if (!rpcauth_uptodatecred(task)) {
 724                 task->tk_action = call_refresh;
 725                 return;
 726         }
 727
 728         task->tk_status  = 0;
 729         task->tk_action  = call_reserveresult;
 730         xprt_reserve(task);
 731 }
 732
 733 /*
 734  * 1b.  Grok the result of xprt_reserve()
 735  */
 736 static void
 737 call_reserveresult(struct rpc_task *task)
 738 {
 739         int status = task->tk_status;
 740
 741         dprint_status(task);
 742
 743         /*
 744          * After a call to xprt_reserve(), we must have either
 745          * a request slot or else an error status.
 746          */
 747         task->tk_status = 0;
 748         if (status >= 0) {
 749                 if (task->tk_rqstp) {
 750                         task->tk_action = call_allocate;
 751                         return;
 752                 }
 753
 754                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 755                                 __func__, status);
 756                 rpc_exit(task, -EIO);
 757                 return;
 758         }
 759
 760         /*
 761          * Even though there was an error, we may have acquired
 762          * a request slot somehow.  Make sure not to leak it.
 763          */
 764         if (task->tk_rqstp) {
 765                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 766                                 __func__, status);
 767                 xprt_release(task);
 768         }
 769
 770         switch (status) {
 771         case -EAGAIN:   /* woken up; retry */
 772                 task->tk_action = call_reserve;
 773                 return;
 774         case -EIO:      /* probably a shutdown */
 775                 break;
 776         default:
 777                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 778                                 __func__, status);
 779                 break;
 780         }
 781         rpc_exit(task, status);
 782 }
 783
 784 /*
 785  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 786  *      (Note: buffer memory is freed in xprt_release).
 787  */
 788 static void
 789 call_allocate(struct rpc_task *task)
 790 {
 791         unsigned int slack = task->tk_msg.rpc_cred->cr_auth->au_cslack;
 792         struct rpc_rqst *req = task->tk_rqstp;
 793         struct rpc_xprt *xprt = task->tk_xprt;
 794         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 795
 796         dprint_status(task);
 797
 798         task->tk_status = 0;
 799         task->tk_action = call_bind;
 800
 801         if (req->rq_buffer)
 802                 return;
 803
 804         if (proc->p_proc != 0) {
 805                 BUG_ON(proc->p_arglen == 0);
 806                 if (proc->p_decode != NULL)
 807                         BUG_ON(proc->p_replen == 0);
 808         }
 809
 810         /*
 811          * Calculate the size (in quads) of the RPC call
 812          * and reply headers, and convert both values
 813          * to byte sizes.
 814          */
 815         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
 816         req->rq_callsize <<= 2;
 817         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
 818         req->rq_rcvsize <<= 2;
 819
 820         req->rq_buffer = xprt->ops->buf_alloc(task,
 821                                         req->rq_callsize + req->rq_rcvsize);
 822         if (req->rq_buffer != NULL)
 823                 return;
 824
 825         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
 826
 827         if (RPC_IS_ASYNC(task) || !signalled()) {
 828                 task->tk_action = call_allocate;
 829                 rpc_delay(task, HZ>>4);
 830                 return;
 831         }
 832
 833         rpc_exit(task, -ERESTARTSYS);
 834 }
 835
 836 static inline int
 837 rpc_task_need_encode(struct rpc_task *task)
 838 {
 839         return task->tk_rqstp->rq_snd_buf.len == 0;
 840 }
 841
 842 static inline void
 843 rpc_task_force_reencode(struct rpc_task *task)
 844 {
 845         task->tk_rqstp->rq_snd_buf.len = 0;
 846 }
 847
 848 static inline void
 849 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
 850 {
 851         buf->head[0].iov_base = start;
 852         buf->head[0].iov_len = len;
 853         buf->tail[0].iov_len = 0;
 854         buf->page_len = 0;
 855         buf->flags = 0;
 856         buf->len = 0;
 857         buf->buflen = len;
 858 }
 859
 860 /*
 861  * 3.   Encode arguments of an RPC call
 862  */
 863 static void
 864 call_encode(struct rpc_task *task)
 865 {
 866         struct rpc_rqst *req = task->tk_rqstp;
 867         kxdrproc_t      encode;
 868         __be32          *p;
 869
 870         dprint_status(task);
 871
 872         rpc_xdr_buf_init(&req->rq_snd_buf,
 873                          req->rq_buffer,
 874                          req->rq_callsize);
 875         rpc_xdr_buf_init(&req->rq_rcv_buf,
 876                          (char *)req->rq_buffer + req->rq_callsize,
 877                          req->rq_rcvsize);
 878
 879         /* Encode header and provided arguments */
 880         encode = task->tk_msg.rpc_proc->p_encode;
 881         if (!(p = call_header(task))) {
 882                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 883                 rpc_exit(task, -EIO);
 884                 return;
 885         }
 886         if (encode == NULL)
 887                 return;
 888
 889         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 890                         task->tk_msg.rpc_argp);
 891         if (task->tk_status == -ENOMEM) {
 892                 /* XXX: Is this sane? */
 893                 rpc_delay(task, 3*HZ);
 894                 task->tk_status = -EAGAIN;
 895         }
 896 }
 897
 898 /*
 899  * 4.   Get the server port number if not yet set
 900  */
 901 static void
 902 call_bind(struct rpc_task *task)
 903 {
 904         struct rpc_xprt *xprt = task->tk_xprt;
 905
 906         dprint_status(task);
 907
 908         task->tk_action = call_connect;
 909         if (!xprt_bound(xprt)) {
 910                 task->tk_action = call_bind_status;
 911                 task->tk_timeout = xprt->bind_timeout;
 912                 xprt->ops->rpcbind(task);
 913         }
 914 }
 915
 916 /*
 917  * 4a.  Sort out bind result
 918  */
 919 static void
 920 call_bind_status(struct rpc_task *task)
 921 {
 922         int status = -EIO;
 923
 924         if (task->tk_status >= 0) {
 925                 dprint_status(task);
 926                 task->tk_status = 0;
 927                 task->tk_action = call_connect;
 928                 return;
 929         }
 930
 931         switch (task->tk_status) {
 932         case -EAGAIN:
 933                 dprintk("RPC: %5u rpcbind waiting for another request "
 934                                 "to finish\n", task->tk_pid);
 935                 /* avoid busy-waiting here -- could be a network outage. */
 936                 rpc_delay(task, 5*HZ);
 937                 goto retry_timeout;
 938         case -EACCES:
 939                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
 940                                 "unavailable\n", task->tk_pid);
 941                 /* fail immediately if this is an RPC ping */
 942                 if (task->tk_msg.rpc_proc->p_proc == 0) {
 943                         status = -EOPNOTSUPP;
 944                         break;
 945                 }
 946                 rpc_delay(task, 3*HZ);
 947                 goto retry_timeout;
 948         case -ETIMEDOUT:
 949                 dprintk("RPC: %5u rpcbind request timed out\n",
 950                                 task->tk_pid);
 951                 goto retry_timeout;
 952         case -EPFNOSUPPORT:
 953                 /* server doesn't support any rpcbind version we know of */
 954                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
 955                                 task->tk_pid);
 956                 break;
 957         case -EPROTONOSUPPORT:
 958                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
 959                                 task->tk_pid);
 960                 task->tk_status = 0;
 961                 task->tk_action = call_bind;
 962                 return;
 963         default:
 964                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 965                                 task->tk_pid, -task->tk_status);
 966         }
 967
 968         rpc_exit(task, status);
 969         return;
 970
 971 retry_timeout:
 972         task->tk_action = call_timeout;
 973 }
 974
 975 /*
 976  * 4b.  Connect to the RPC server
 977  */
 978 static void
 979 call_connect(struct rpc_task *task)
 980 {
 981         struct rpc_xprt *xprt = task->tk_xprt;
 982
 983         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
 984                         task->tk_pid, xprt,
 985                         (xprt_connected(xprt) ? "is" : "is not"));
 986
 987         task->tk_action = call_transmit;
 988         if (!xprt_connected(xprt)) {
 989                 task->tk_action = call_connect_status;
 990                 if (task->tk_status < 0)
 991                         return;
 992                 xprt_connect(task);
 993         }
 994 }
 995
 996 /*
 997  * 4c.  Sort out connect result
 998  */
 999 static void
1000 call_connect_status(struct rpc_task *task)
1001 {
1002         struct rpc_clnt *clnt = task->tk_client;
1003         int status = task->tk_status;
1004
1005         dprint_status(task);
1006
1007         task->tk_status = 0;
1008         if (status >= 0) {
1009                 clnt->cl_stats->netreconn++;
1010                 task->tk_action = call_transmit;
1011                 return;
1012         }
1013
1014         /* Something failed: remote service port may have changed */
1015         rpc_force_rebind(clnt);
1016
1017         switch (status) {
1018         case -ENOTCONN:
1019         case -EAGAIN:
1020                 task->tk_action = call_bind;
1021                 if (!RPC_IS_SOFT(task))
1022                         return;
1023                 /* if soft mounted, test if we've timed out */
1024         case -ETIMEDOUT:
1025                 task->tk_action = call_timeout;
1026                 return;
1027         }
1028         rpc_exit(task, -EIO);
1029 }
1030
1031 /*
1032  * 5.   Transmit the RPC request, and wait for reply
1033  */
1034 static void
1035 call_transmit(struct rpc_task *task)
1036 {
1037         dprint_status(task);
1038
1039         task->tk_action = call_status;
1040         if (task->tk_status < 0)
1041                 return;
1042         task->tk_status = xprt_prepare_transmit(task);
1043         if (task->tk_status != 0)
1044                 return;
1045         task->tk_action = call_transmit_status;
1046         /* Encode here so that rpcsec_gss can use correct sequence number. */
1047         if (rpc_task_need_encode(task)) {
1048                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1049                 call_encode(task);
1050                 /* Did the encode result in an error condition? */
1051                 if (task->tk_status != 0)
1052                         return;
1053         }
1054         xprt_transmit(task);
1055         if (task->tk_status < 0)
1056                 return;
1057         /*
1058          * On success, ensure that we call xprt_end_transmit() before sleeping
1059          * in order to allow access to the socket to other RPC requests.
1060          */
1061         call_transmit_status(task);
1062         if (task->tk_msg.rpc_proc->p_decode != NULL)
1063                 return;
1064         task->tk_action = rpc_exit_task;
1065         rpc_wake_up_queued_task(&task->tk_xprt->pending, task);
1066 }
1067
1068 /*
1069  * 5a.  Handle cleanup after a transmission
1070  */
1071 static void
1072 call_transmit_status(struct rpc_task *task)
1073 {
1074         task->tk_action = call_status;
1075         /*
1076          * Special case: if we've been waiting on the socket's write_space()
1077          * callback, then don't call xprt_end_transmit().
1078          */
1079         if (task->tk_status == -EAGAIN)
1080                 return;
1081         xprt_end_transmit(task);
1082         rpc_task_force_reencode(task);
1083 }
1084
1085 /*
1086  * 6.   Sort out the RPC call status
1087  */
1088 static void
1089 call_status(struct rpc_task *task)
1090 {
1091         struct rpc_clnt *clnt = task->tk_client;
1092         struct rpc_rqst *req = task->tk_rqstp;
1093         int             status;
1094
1095         if (req->rq_received > 0 && !req->rq_bytes_sent)
1096                 task->tk_status = req->rq_received;
1097
1098         dprint_status(task);
1099
1100         status = task->tk_status;
1101         if (status >= 0) {
1102                 task->tk_action = call_decode;
1103                 return;
1104         }
1105
1106         task->tk_status = 0;
1107         switch(status) {
1108         case -EHOSTDOWN:
1109         case -EHOSTUNREACH:
1110         case -ENETUNREACH:
1111                 /*
1112                  * Delay any retries for 3 seconds, then handle as if it
1113                  * were a timeout.
1114                  */
1115                 rpc_delay(task, 3*HZ);
1116         case -ETIMEDOUT:
1117                 task->tk_action = call_timeout;
1118                 if (task->tk_client->cl_discrtry)
1119                         xprt_conditional_disconnect(task->tk_xprt,
1120                                         req->rq_connect_cookie);
1121                 break;
1122         case -ECONNREFUSED:
1123         case -ENOTCONN:
1124                 rpc_force_rebind(clnt);
1125                 task->tk_action = call_bind;
1126                 break;
1127         case -EAGAIN:
1128                 task->tk_action = call_transmit;
1129                 break;
1130         case -EIO:
1131                 /* shutdown or soft timeout */
1132                 rpc_exit(task, status);
1133                 break;
1134         default:
1135                 printk("%s: RPC call returned error %d\n",
1136                                clnt->cl_protname, -status);
1137                 rpc_exit(task, status);
1138         }
1139 }
1140
1141 /*
1142  * 6a.  Handle RPC timeout
1143  *      We do not release the request slot, so we keep using the
1144  *      same XID for all retransmits.
1145  */
1146 static void
1147 call_timeout(struct rpc_task *task)
1148 {
1149         struct rpc_clnt *clnt = task->tk_client;
1150
1151         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1152                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1153                 goto retry;
1154         }
1155
1156         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1157         task->tk_timeouts++;
1158
1159         if (RPC_IS_SOFT(task)) {
1160                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1161                                 clnt->cl_protname, clnt->cl_server);
1162                 rpc_exit(task, -EIO);
1163                 return;
1164         }
1165
1166         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1167                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1168                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1169                         clnt->cl_protname, clnt->cl_server);
1170         }
1171         rpc_force_rebind(clnt);
1172         /*
1173          * Did our request time out due to an RPCSEC_GSS out-of-sequence
1174          * event? RFC2203 requires the server to drop all such requests.
1175          */
1176         rpcauth_invalcred(task);
1177
1178 retry:
1179         clnt->cl_stats->rpcretrans++;
1180         task->tk_action = call_bind;
1181         task->tk_status = 0;
1182 }
1183
1184 /*
1185  * 7.   Decode the RPC reply
1186  */
1187 static void
1188 call_decode(struct rpc_task *task)
1189 {
1190         struct rpc_clnt *clnt = task->tk_client;
1191         struct rpc_rqst *req = task->tk_rqstp;
1192         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1193         __be32          *p;
1194
1195         dprintk("RPC: %5u call_decode (status %d)\n",
1196                         task->tk_pid, task->tk_status);
1197
1198         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1199                 printk(KERN_NOTICE "%s: server %s OK\n",
1200                         clnt->cl_protname, clnt->cl_server);
1201                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1202         }
1203
1204         /*
1205          * Ensure that we see all writes made by xprt_complete_rqst()
1206          * before it changed req->rq_received.
1207          */
1208         smp_rmb();
1209         req->rq_rcv_buf.len = req->rq_private_buf.len;
1210
1211         /* Check that the softirq receive buffer is valid */
1212         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1213                                 sizeof(req->rq_rcv_buf)) != 0);
1214
1215         if (req->rq_rcv_buf.len < 12) {
1216                 if (!RPC_IS_SOFT(task)) {
1217                         task->tk_action = call_bind;
1218                         clnt->cl_stats->rpcretrans++;
1219                         goto out_retry;
1220                 }
1221                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1222                                 clnt->cl_protname, task->tk_status);
1223                 task->tk_action = call_timeout;
1224                 goto out_retry;
1225         }
1226
1227         /* Verify the RPC header */
1228         p = call_verify(task);
1229         if (IS_ERR(p)) {
1230                 if (p == ERR_PTR(-EAGAIN))
1231                         goto out_retry;
1232                 return;
1233         }
1234
1235         task->tk_action = rpc_exit_task;
1236
1237         if (decode) {
1238                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1239                                                       task->tk_msg.rpc_resp);
1240         }
1241         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1242                         task->tk_status);
1243         return;
1244 out_retry:
1245         task->tk_status = 0;
1246         /* Note: call_verify() may have freed the RPC slot */
1247         if (task->tk_rqstp == req) {
1248                 req->rq_received = req->rq_rcv_buf.len = 0;
1249                 if (task->tk_client->cl_discrtry)
1250                         xprt_conditional_disconnect(task->tk_xprt,
1251                                         req->rq_connect_cookie);
1252         }
1253 }
1254
1255 /*
1256  * 8.   Refresh the credentials if rejected by the server
1257  */
1258 static void
1259 call_refresh(struct rpc_task *task)
1260 {
1261         dprint_status(task);
1262
1263         task->tk_action = call_refreshresult;
1264         task->tk_status = 0;
1265         task->tk_client->cl_stats->rpcauthrefresh++;
1266         rpcauth_refreshcred(task);
1267 }
1268
1269 /*
1270  * 8a.  Process the results of a credential refresh
1271  */
1272 static void
1273 call_refreshresult(struct rpc_task *task)
1274 {
1275         int status = task->tk_status;
1276
1277         dprint_status(task);
1278
1279         task->tk_status = 0;
1280         task->tk_action = call_reserve;
1281         if (status >= 0 && rpcauth_uptodatecred(task))
1282                 return;
1283         if (status == -EACCES) {
1284                 rpc_exit(task, -EACCES);
1285                 return;
1286         }
1287         task->tk_action = call_refresh;
1288         if (status != -ETIMEDOUT)
1289                 rpc_delay(task, 3*HZ);
1290         return;
1291 }
1292
1293 /*
1294  * Call header serialization
1295  */
1296 static __be32 *
1297 call_header(struct rpc_task *task)
1298 {
1299         struct rpc_clnt *clnt = task->tk_client;
1300         struct rpc_rqst *req = task->tk_rqstp;
1301         __be32          *p = req->rq_svec[0].iov_base;
1302
1303         /* FIXME: check buffer size? */
1304
1305         p = xprt_skip_transport_header(task->tk_xprt, p);
1306         *p++ = req->rq_xid;             /* XID */
1307         *p++ = htonl(RPC_CALL);         /* CALL */
1308         *p++ = htonl(RPC_VERSION);      /* RPC version */
1309         *p++ = htonl(clnt->cl_prog);    /* program number */
1310         *p++ = htonl(clnt->cl_vers);    /* program version */
1311         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1312         p = rpcauth_marshcred(task, p);
1313         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1314         return p;
1315 }
1316
1317 /*
1318  * Reply header verification
1319  */
1320 static __be32 *
1321 call_verify(struct rpc_task *task)
1322 {
1323         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1324         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1325         __be32  *p = iov->iov_base;
1326         u32 n;
1327         int error = -EACCES;
1328
1329         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1330                 /* RFC-1014 says that the representation of XDR data must be a
1331                  * multiple of four bytes
1332                  * - if it isn't pointer subtraction in the NFS client may give
1333                  *   undefined results
1334                  */
1335                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
1336                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
1337                        task->tk_rqstp->rq_rcv_buf.len);
1338                 goto out_eio;
1339         }
1340         if ((len -= 3) < 0)
1341                 goto out_overflow;
1342         p += 1; /* skip XID */
1343
1344         if ((n = ntohl(*p++)) != RPC_REPLY) {
1345                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1346                                 task->tk_pid, __func__, n);
1347                 goto out_garbage;
1348         }
1349         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1350                 if (--len < 0)
1351                         goto out_overflow;
1352                 switch ((n = ntohl(*p++))) {
1353                         case RPC_AUTH_ERROR:
1354                                 break;
1355                         case RPC_MISMATCH:
1356                                 dprintk("RPC: %5u %s: RPC call version "
1357                                                 "mismatch!\n",
1358                                                 task->tk_pid, __func__);
1359                                 error = -EPROTONOSUPPORT;
1360                                 goto out_err;
1361                         default:
1362                                 dprintk("RPC: %5u %s: RPC call rejected, "
1363                                                 "unknown error: %x\n",
1364                                                 task->tk_pid, __func__, n);
1365                                 goto out_eio;
1366                 }
1367                 if (--len < 0)
1368                         goto out_overflow;
1369                 switch ((n = ntohl(*p++))) {
1370                 case RPC_AUTH_REJECTEDCRED:
1371                 case RPC_AUTH_REJECTEDVERF:
1372                 case RPCSEC_GSS_CREDPROBLEM:
1373                 case RPCSEC_GSS_CTXPROBLEM:
1374                         if (!task->tk_cred_retry)
1375                                 break;
1376                         task->tk_cred_retry--;
1377                         dprintk("RPC: %5u %s: retry stale creds\n",
1378                                         task->tk_pid, __func__);
1379                         rpcauth_invalcred(task);
1380                         /* Ensure we obtain a new XID! */
1381                         xprt_release(task);
1382                         task->tk_action = call_refresh;
1383                         goto out_retry;
1384                 case RPC_AUTH_BADCRED:
1385                 case RPC_AUTH_BADVERF:
1386                         /* possibly garbled cred/verf? */
1387                         if (!task->tk_garb_retry)
1388                                 break;
1389                         task->tk_garb_retry--;
1390                         dprintk("RPC: %5u %s: retry garbled creds\n",
1391                                         task->tk_pid, __func__);
1392                         task->tk_action = call_bind;
1393                         goto out_retry;
1394                 case RPC_AUTH_TOOWEAK:
1395                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1396                                "authentication.\n", task->tk_client->cl_server);
1397                         break;
1398                 default:
1399                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
1400                                         task->tk_pid, __func__, n);
1401                         error = -EIO;
1402                 }
1403                 dprintk("RPC: %5u %s: call rejected %d\n",
1404                                 task->tk_pid, __func__, n);
1405                 goto out_err;
1406         }
1407         if (!(p = rpcauth_checkverf(task, p))) {
1408                 dprintk("RPC: %5u %s: auth check failed\n",
1409                                 task->tk_pid, __func__);
1410                 goto out_garbage;               /* bad verifier, retry */
1411         }
1412         len = p - (__be32 *)iov->iov_base - 1;
1413         if (len < 0)
1414                 goto out_overflow;
1415         switch ((n = ntohl(*p++))) {
1416         case RPC_SUCCESS:
1417                 return p;
1418         case RPC_PROG_UNAVAIL:
1419                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1420                                 task->tk_pid, __func__,
1421                                 (unsigned int)task->tk_client->cl_prog,
1422                                 task->tk_client->cl_server);
1423                 error = -EPFNOSUPPORT;
1424                 goto out_err;
1425         case RPC_PROG_MISMATCH:
1426                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1427                                 "server %s\n", task->tk_pid, __func__,
1428                                 (unsigned int)task->tk_client->cl_prog,
1429                                 (unsigned int)task->tk_client->cl_vers,
1430                                 task->tk_client->cl_server);
1431                 error = -EPROTONOSUPPORT;
1432                 goto out_err;
1433         case RPC_PROC_UNAVAIL:
1434                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1435                                 "version %u on server %s\n",
1436                                 task->tk_pid, __func__,
1437                                 task->tk_msg.rpc_proc,
1438                                 task->tk_client->cl_prog,
1439                                 task->tk_client->cl_vers,
1440                                 task->tk_client->cl_server);
1441                 error = -EOPNOTSUPP;
1442                 goto out_err;
1443         case RPC_GARBAGE_ARGS:
1444                 dprintk("RPC: %5u %s: server saw garbage\n",
1445                                 task->tk_pid, __func__);
1446                 break;                  /* retry */
1447         default:
1448                 dprintk("RPC: %5u %s: server accept status: %x\n",
1449                                 task->tk_pid, __func__, n);
1450                 /* Also retry */
1451         }
1452
1453 out_garbage:
1454         task->tk_client->cl_stats->rpcgarbage++;
1455         if (task->tk_garb_retry) {
1456                 task->tk_garb_retry--;
1457                 dprintk("RPC: %5u %s: retrying\n",
1458                                 task->tk_pid, __func__);
1459                 task->tk_action = call_bind;
1460 out_retry:
1461                 return ERR_PTR(-EAGAIN);
1462         }
1463 out_eio:
1464         error = -EIO;
1465 out_err:
1466         rpc_exit(task, error);
1467         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1468                         __func__, error);
1469         return ERR_PTR(error);
1470 out_overflow:
1471         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1472                         __func__);
1473         goto out_garbage;
1474 }
1475
1476 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1477 {
1478         return 0;
1479 }
1480
1481 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1482 {
1483         return 0;
1484 }
1485
1486 static struct rpc_procinfo rpcproc_null = {
1487         .p_encode = rpcproc_encode_null,
1488         .p_decode = rpcproc_decode_null,
1489 };
1490
1491 static int rpc_ping(struct rpc_clnt *clnt, int flags)
1492 {
1493         struct rpc_message msg = {
1494                 .rpc_proc = &rpcproc_null,
1495         };
1496         int err;
1497         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1498         err = rpc_call_sync(clnt, &msg, flags);
1499         put_rpccred(msg.rpc_cred);
1500         return err;
1501 }
1502
1503 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1504 {
1505         struct rpc_message msg = {
1506                 .rpc_proc = &rpcproc_null,
1507                 .rpc_cred = cred,
1508         };
1509         struct rpc_task_setup task_setup_data = {
1510                 .rpc_client = clnt,
1511                 .rpc_message = &msg,
1512                 .callback_ops = &rpc_default_ops,
1513                 .flags = flags,
1514         };
1515         return rpc_run_task(&task_setup_data);
1516 }
1517 EXPORT_SYMBOL_GPL(rpc_call_null);
1518
1519 #ifdef RPC_DEBUG
1520 void rpc_show_tasks(void)
1521 {
1522         struct rpc_clnt *clnt;
1523         struct rpc_task *t;
1524
1525         spin_lock(&rpc_client_lock);
1526         if (list_empty(&all_clients))
1527                 goto out;
1528         printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
1529                 "-rpcwait -action- ---ops--\n");
1530         list_for_each_entry(clnt, &all_clients, cl_clients) {
1531                 if (list_empty(&clnt->cl_tasks))
1532                         continue;
1533                 spin_lock(&clnt->cl_lock);
1534                 list_for_each_entry(t, &clnt->cl_tasks, tk_task) {
1535                         const char *rpc_waitq = "none";
1536                         int proc;
1537
1538                         if (t->tk_msg.rpc_proc)
1539                                 proc = t->tk_msg.rpc_proc->p_proc;
1540                         else
1541                                 proc = -1;
1542
1543                         if (RPC_IS_QUEUED(t))
1544                                 rpc_waitq = rpc_qname(t->tk_waitqueue);
1545
1546                         printk("%5u %04d %04x %6d %8p %6d %8p %8ld %8s %8p %8p\n",
1547                                 t->tk_pid, proc,
1548                                 t->tk_flags, t->tk_status,
1549                                 t->tk_client,
1550                                 (t->tk_client ? t->tk_client->cl_prog : 0),
1551                                 t->tk_rqstp, t->tk_timeout,
1552                                 rpc_waitq,
1553                                 t->tk_action, t->tk_ops);
1554                 }
1555                 spin_unlock(&clnt->cl_lock);
1556         }
1557 out:
1558         spin_unlock(&rpc_client_lock);
1559 }
1560 #endif