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 <[email protected]>
  21  *  Copyright (C) 1995,1996 Olaf Kirch <[email protected]>
  22  */
  23
  24 #include <asm/system.h>
  25
  26 #include <linux/module.h>
  27 #include <linux/types.h>
  28 #include <linux/mm.h>
  29 #include <linux/slab.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/utsname.h>
  32 #include <linux/workqueue.h>
  33
  34 #include <linux/sunrpc/clnt.h>
  35 #include <linux/sunrpc/rpc_pipe_fs.h>
  36 #include <linux/sunrpc/metrics.h>
  37
  38
  39 #ifdef RPC_DEBUG
  40 # define RPCDBG_FACILITY        RPCDBG_CALL
  41 #endif
  42
  43 #define dprint_status(t)                                        \
  44         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  45                         __FUNCTION__, t->tk_status)
  46
  47 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  48
  49
  50 static void     call_start(struct rpc_task *task);
  51 static void     call_reserve(struct rpc_task *task);
  52 static void     call_reserveresult(struct rpc_task *task);
  53 static void     call_allocate(struct rpc_task *task);
  54 static void     call_encode(struct rpc_task *task);
  55 static void     call_decode(struct rpc_task *task);
  56 static void     call_bind(struct rpc_task *task);
  57 static void     call_bind_status(struct rpc_task *task);
  58 static void     call_transmit(struct rpc_task *task);
  59 static void     call_status(struct rpc_task *task);
  60 static void     call_transmit_status(struct rpc_task *task);
  61 static void     call_refresh(struct rpc_task *task);
  62 static void     call_refreshresult(struct rpc_task *task);
  63 static void     call_timeout(struct rpc_task *task);
  64 static void     call_connect(struct rpc_task *task);
  65 static void     call_connect_status(struct rpc_task *task);
  66 static __be32 * call_header(struct rpc_task *task);
  67 static __be32 * call_verify(struct rpc_task *task);
  68
  69
  70 static int
  71 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  72 {
  73         static uint32_t clntid;
  74         int error;
  75
  76         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  77         clnt->cl_dentry = ERR_PTR(-ENOENT);
  78         if (dir_name == NULL)
  79                 return 0;
  80
  81         clnt->cl_vfsmnt = rpc_get_mount();
  82         if (IS_ERR(clnt->cl_vfsmnt))
  83                 return PTR_ERR(clnt->cl_vfsmnt);
  84
  85         for (;;) {
  86                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  87                                 "%s/clnt%x", dir_name,
  88                                 (unsigned int)clntid++);
  89                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  90                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  91                 if (!IS_ERR(clnt->cl_dentry))
  92                         return 0;
  93                 error = PTR_ERR(clnt->cl_dentry);
  94                 if (error != -EEXIST) {
  95                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  96                                         clnt->cl_pathname, error);
  97                         rpc_put_mount();
  98                         return error;
  99                 }
 100         }
 101 }
 102
 103 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
 104 {
 105         struct rpc_version      *version;
 106         struct rpc_clnt         *clnt = NULL;
 107         struct rpc_auth         *auth;
 108         int err;
 109         int len;
 110
 111         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 112                         program->name, servname, xprt);
 113
 114         err = -EINVAL;
 115         if (!xprt)
 116                 goto out_no_xprt;
 117         if (vers >= program->nrvers || !(version = program->version[vers]))
 118                 goto out_err;
 119
 120         err = -ENOMEM;
 121         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 122         if (!clnt)
 123                 goto out_err;
 124         atomic_set(&clnt->cl_count, 1);
 125         clnt->cl_parent = clnt;
 126
 127         clnt->cl_server = clnt->cl_inline_name;
 128         len = strlen(servname) + 1;
 129         if (len > sizeof(clnt->cl_inline_name)) {
 130                 char *buf = kmalloc(len, GFP_KERNEL);
 131                 if (buf != 0)
 132                         clnt->cl_server = buf;
 133                 else
 134                         len = sizeof(clnt->cl_inline_name);
 135         }
 136         strlcpy(clnt->cl_server, servname, len);
 137
 138         clnt->cl_xprt     = xprt;
 139         clnt->cl_procinfo = version->procs;
 140         clnt->cl_maxproc  = version->nrprocs;
 141         clnt->cl_protname = program->name;
 142         clnt->cl_prog     = program->number;
 143         clnt->cl_vers     = version->number;
 144         clnt->cl_stats    = program->stats;
 145         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 146         err = -ENOMEM;
 147         if (clnt->cl_metrics == NULL)
 148                 goto out_no_stats;
 149         clnt->cl_program  = program;
 150         INIT_LIST_HEAD(&clnt->cl_tasks);
 151         spin_lock_init(&clnt->cl_lock);
 152
 153         if (!xprt_bound(clnt->cl_xprt))
 154                 clnt->cl_autobind = 1;
 155
 156         clnt->cl_rtt = &clnt->cl_rtt_default;
 157         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 158
 159         kref_init(&clnt->cl_kref);
 160
 161         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 162         if (err < 0)
 163                 goto out_no_path;
 164
 165         auth = rpcauth_create(flavor, clnt);
 166         if (IS_ERR(auth)) {
 167                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 168                                 flavor);
 169                 err = PTR_ERR(auth);
 170                 goto out_no_auth;
 171         }
 172
 173         /* save the nodename */
 174         clnt->cl_nodelen = strlen(utsname()->nodename);
 175         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 176                 clnt->cl_nodelen = UNX_MAXNODENAME;
 177         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 178         rpc_register_client(clnt);
 179         return clnt;
 180
 181 out_no_auth:
 182         if (!IS_ERR(clnt->cl_dentry)) {
 183                 rpc_rmdir(clnt->cl_dentry);
 184                 rpc_put_mount();
 185         }
 186 out_no_path:
 187         rpc_free_iostats(clnt->cl_metrics);
 188 out_no_stats:
 189         if (clnt->cl_server != clnt->cl_inline_name)
 190                 kfree(clnt->cl_server);
 191         kfree(clnt);
 192 out_err:
 193         xprt_put(xprt);
 194 out_no_xprt:
 195         return ERR_PTR(err);
 196 }
 197
 198 /*
 199  * rpc_create - create an RPC client and transport with one call
 200  * @args: rpc_clnt create argument structure
 201  *
 202  * Creates and initializes an RPC transport and an RPC client.
 203  *
 204  * It can ping the server in order to determine if it is up, and to see if
 205  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 206  * this behavior so asynchronous tasks can also use rpc_create.
 207  */
 208 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 209 {
 210         struct rpc_xprt *xprt;
 211         struct rpc_clnt *clnt;
 212
 213         xprt = xprt_create_transport(args->protocol, args->address,
 214                                         args->addrsize, args->timeout);
 215         if (IS_ERR(xprt))
 216                 return (struct rpc_clnt *)xprt;
 217
 218         /*
 219          * By default, kernel RPC client connects from a reserved port.
 220          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 221          * but it is always enabled for rpciod, which handles the connect
 222          * operation.
 223          */
 224         xprt->resvport = 1;
 225         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 226                 xprt->resvport = 0;
 227
 228         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 229                         args->program->name, args->servername, xprt);
 230
 231         clnt = rpc_new_client(xprt, args->servername, args->program,
 232                                 args->version, args->authflavor);
 233         if (IS_ERR(clnt))
 234                 return clnt;
 235
 236         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 237                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 238                 if (err != 0) {
 239                         rpc_shutdown_client(clnt);
 240                         return ERR_PTR(err);
 241                 }
 242         }
 243
 244         clnt->cl_softrtry = 1;
 245         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 246                 clnt->cl_softrtry = 0;
 247
 248         if (args->flags & RPC_CLNT_CREATE_INTR)
 249                 clnt->cl_intr = 1;
 250         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 251                 clnt->cl_autobind = 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         new->cl_metrics = rpc_alloc_iostats(clnt);
 275         if (new->cl_metrics == NULL)
 276                 goto out_no_stats;
 277         kref_init(&new->cl_kref);
 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         INIT_LIST_HEAD(&new->cl_tasks);
 287         spin_lock_init(&new->cl_lock);
 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         rpc_register_client(new);
 292         return new;
 293 out_no_path:
 294         rpc_free_iostats(new->cl_metrics);
 295 out_no_stats:
 296         kfree(new);
 297 out_no_clnt:
 298         dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
 299         return ERR_PTR(err);
 300 }
 301
 302 /*
 303  * Properly shut down an RPC client, terminating all outstanding
 304  * requests.
 305  */
 306 int
 307 rpc_shutdown_client(struct rpc_clnt *clnt)
 308 {
 309         dprintk("RPC:       shutting down %s client for %s\n",
 310                         clnt->cl_protname, clnt->cl_server);
 311
 312         while (!list_empty(&clnt->cl_tasks)) {
 313                 rpc_killall_tasks(clnt);
 314                 wait_event_timeout(destroy_wait,
 315                         list_empty(&clnt->cl_tasks), 1*HZ);
 316         }
 317
 318         return rpc_destroy_client(clnt);
 319 }
 320
 321 /*
 322  * Free an RPC client
 323  */
 324 static void
 325 rpc_free_client(struct kref *kref)
 326 {
 327         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
 328
 329         dprintk("RPC:       destroying %s client for %s\n",
 330                         clnt->cl_protname, clnt->cl_server);
 331         if (clnt->cl_auth) {
 332                 rpcauth_destroy(clnt->cl_auth);
 333                 clnt->cl_auth = NULL;
 334         }
 335         if (!IS_ERR(clnt->cl_dentry)) {
 336                 rpc_rmdir(clnt->cl_dentry);
 337                 rpc_put_mount();
 338         }
 339         if (clnt->cl_parent != clnt) {
 340                 rpc_destroy_client(clnt->cl_parent);
 341                 goto out_free;
 342         }
 343         if (clnt->cl_server != clnt->cl_inline_name)
 344                 kfree(clnt->cl_server);
 345 out_free:
 346         rpc_unregister_client(clnt);
 347         rpc_free_iostats(clnt->cl_metrics);
 348         clnt->cl_metrics = NULL;
 349         xprt_put(clnt->cl_xprt);
 350         kfree(clnt);
 351 }
 352
 353 /*
 354  * Release reference to the RPC client
 355  */
 356 void
 357 rpc_release_client(struct rpc_clnt *clnt)
 358 {
 359         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 360
 361         if (list_empty(&clnt->cl_tasks))
 362                 wake_up(&destroy_wait);
 363         kref_put(&clnt->cl_kref, rpc_free_client);
 364 }
 365
 366 /*
 367  * Delete an RPC client
 368  */
 369 int
 370 rpc_destroy_client(struct rpc_clnt *clnt)
 371 {
 372         if (!atomic_dec_and_test(&clnt->cl_count))
 373                 return 1;
 374         kref_put(&clnt->cl_kref, rpc_free_client);
 375         return 0;
 376 }
 377
 378 /**
 379  * rpc_bind_new_program - bind a new RPC program to an existing client
 380  * @old - old rpc_client
 381  * @program - rpc program to set
 382  * @vers - rpc program version
 383  *
 384  * Clones the rpc client and sets up a new RPC program. This is mainly
 385  * of use for enabling different RPC programs to share the same transport.
 386  * The Sun NFSv2/v3 ACL protocol can do this.
 387  */
 388 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 389                                       struct rpc_program *program,
 390                                       int vers)
 391 {
 392         struct rpc_clnt *clnt;
 393         struct rpc_version *version;
 394         int err;
 395
 396         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 397         version = program->version[vers];
 398         clnt = rpc_clone_client(old);
 399         if (IS_ERR(clnt))
 400                 goto out;
 401         clnt->cl_procinfo = version->procs;
 402         clnt->cl_maxproc  = version->nrprocs;
 403         clnt->cl_protname = program->name;
 404         clnt->cl_prog     = program->number;
 405         clnt->cl_vers     = version->number;
 406         clnt->cl_stats    = program->stats;
 407         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 408         if (err != 0) {
 409                 rpc_shutdown_client(clnt);
 410                 clnt = ERR_PTR(err);
 411         }
 412 out:
 413         return clnt;
 414 }
 415
 416 /*
 417  * Default callback for async RPC calls
 418  */
 419 static void
 420 rpc_default_callback(struct rpc_task *task, void *data)
 421 {
 422 }
 423
 424 static const struct rpc_call_ops rpc_default_ops = {
 425         .rpc_call_done = rpc_default_callback,
 426 };
 427
 428 /*
 429  *      Export the signal mask handling for synchronous code that
 430  *      sleeps on RPC calls
 431  */
 432 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 433
 434 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 435 {
 436         unsigned long   sigallow = sigmask(SIGKILL);
 437         sigset_t sigmask;
 438
 439         /* Block all signals except those listed in sigallow */
 440         if (intr)
 441                 sigallow |= RPC_INTR_SIGNALS;
 442         siginitsetinv(&sigmask, sigallow);
 443         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 444 }
 445
 446 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 447 {
 448         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 449 }
 450
 451 static inline void rpc_restore_sigmask(sigset_t *oldset)
 452 {
 453         sigprocmask(SIG_SETMASK, oldset, NULL);
 454 }
 455
 456 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 457 {
 458         rpc_save_sigmask(oldset, clnt->cl_intr);
 459 }
 460
 461 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 462 {
 463         rpc_restore_sigmask(oldset);
 464 }
 465
 466 /*
 467  * New rpc_call implementation
 468  */
 469 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 470 {
 471         struct rpc_task *task;
 472         sigset_t        oldset;
 473         int             status;
 474
 475         BUG_ON(flags & RPC_TASK_ASYNC);
 476
 477         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 478         if (task == NULL)
 479                 return -ENOMEM;
 480
 481         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 482         rpc_task_sigmask(task, &oldset);
 483
 484         /* Set up the call info struct and execute the task */
 485         rpc_call_setup(task, msg, 0);
 486         if (task->tk_status == 0) {
 487                 atomic_inc(&task->tk_count);
 488                 rpc_execute(task);
 489         }
 490         status = task->tk_status;
 491         rpc_put_task(task);
 492         rpc_restore_sigmask(&oldset);
 493         return status;
 494 }
 495
 496 /*
 497  * New rpc_call implementation
 498  */
 499 int
 500 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 501                const struct rpc_call_ops *tk_ops, void *data)
 502 {
 503         struct rpc_task *task;
 504         sigset_t        oldset;
 505         int             status;
 506
 507         flags |= RPC_TASK_ASYNC;
 508
 509         /* Create/initialize a new RPC task */
 510         status = -ENOMEM;
 511         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 512                 goto out_release;
 513
 514         /* Mask signals on GSS_AUTH upcalls */
 515         rpc_task_sigmask(task, &oldset);
 516
 517         rpc_call_setup(task, msg, 0);
 518
 519         /* Set up the call info struct and execute the task */
 520         status = task->tk_status;
 521         if (status == 0)
 522                 rpc_execute(task);
 523         else
 524                 rpc_put_task(task);
 525
 526         rpc_restore_sigmask(&oldset);
 527         return status;
 528 out_release:
 529         rpc_release_calldata(tk_ops, data);
 530         return status;
 531 }
 532
 533
 534 void
 535 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 536 {
 537         task->tk_msg   = *msg;
 538         task->tk_flags |= flags;
 539         /* Bind the user cred */
 540         if (task->tk_msg.rpc_cred != NULL)
 541                 rpcauth_holdcred(task);
 542         else
 543                 rpcauth_bindcred(task);
 544
 545         if (task->tk_status == 0)
 546                 task->tk_action = call_start;
 547         else
 548                 task->tk_action = rpc_exit_task;
 549 }
 550
 551 /**
 552  * rpc_peeraddr - extract remote peer address from clnt's xprt
 553  * @clnt: RPC client structure
 554  * @buf: target buffer
 555  * @size: length of target buffer
 556  *
 557  * Returns the number of bytes that are actually in the stored address.
 558  */
 559 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 560 {
 561         size_t bytes;
 562         struct rpc_xprt *xprt = clnt->cl_xprt;
 563
 564         bytes = sizeof(xprt->addr);
 565         if (bytes > bufsize)
 566                 bytes = bufsize;
 567         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 568         return xprt->addrlen;
 569 }
 570 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 571
 572 /**
 573  * rpc_peeraddr2str - return remote peer address in printable format
 574  * @clnt: RPC client structure
 575  * @format: address format
 576  *
 577  */
 578 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 579 {
 580         struct rpc_xprt *xprt = clnt->cl_xprt;
 581
 582         if (xprt->address_strings[format] != NULL)
 583                 return xprt->address_strings[format];
 584         else
 585                 return "unprintable";
 586 }
 587 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 588
 589 void
 590 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 591 {
 592         struct rpc_xprt *xprt = clnt->cl_xprt;
 593         if (xprt->ops->set_buffer_size)
 594                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 595 }
 596
 597 /*
 598  * Return size of largest payload RPC client can support, in bytes
 599  *
 600  * For stream transports, this is one RPC record fragment (see RFC
 601  * 1831), as we don't support multi-record requests yet.  For datagram
 602  * transports, this is the size of an IP packet minus the IP, UDP, and
 603  * RPC header sizes.
 604  */
 605 size_t rpc_max_payload(struct rpc_clnt *clnt)
 606 {
 607         return clnt->cl_xprt->max_payload;
 608 }
 609 EXPORT_SYMBOL_GPL(rpc_max_payload);
 610
 611 /**
 612  * rpc_force_rebind - force transport to check that remote port is unchanged
 613  * @clnt: client to rebind
 614  *
 615  */
 616 void rpc_force_rebind(struct rpc_clnt *clnt)
 617 {
 618         if (clnt->cl_autobind)
 619                 xprt_clear_bound(clnt->cl_xprt);
 620 }
 621 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 622
 623 /*
 624  * Restart an (async) RPC call. Usually called from within the
 625  * exit handler.
 626  */
 627 void
 628 rpc_restart_call(struct rpc_task *task)
 629 {
 630         if (RPC_ASSASSINATED(task))
 631                 return;
 632
 633         task->tk_action = call_start;
 634 }
 635
 636 /*
 637  * 0.  Initial state
 638  *
 639  *     Other FSM states can be visited zero or more times, but
 640  *     this state is visited exactly once for each RPC.
 641  */
 642 static void
 643 call_start(struct rpc_task *task)
 644 {
 645         struct rpc_clnt *clnt = task->tk_client;
 646
 647         dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
 648                         clnt->cl_protname, clnt->cl_vers,
 649                         task->tk_msg.rpc_proc->p_proc,
 650                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 651
 652         /* Increment call count */
 653         task->tk_msg.rpc_proc->p_count++;
 654         clnt->cl_stats->rpccnt++;
 655         task->tk_action = call_reserve;
 656 }
 657
 658 /*
 659  * 1.   Reserve an RPC call slot
 660  */
 661 static void
 662 call_reserve(struct rpc_task *task)
 663 {
 664         dprint_status(task);
 665
 666         if (!rpcauth_uptodatecred(task)) {
 667                 task->tk_action = call_refresh;
 668                 return;
 669         }
 670
 671         task->tk_status  = 0;
 672         task->tk_action  = call_reserveresult;
 673         xprt_reserve(task);
 674 }
 675
 676 /*
 677  * 1b.  Grok the result of xprt_reserve()
 678  */
 679 static void
 680 call_reserveresult(struct rpc_task *task)
 681 {
 682         int status = task->tk_status;
 683
 684         dprint_status(task);
 685
 686         /*
 687          * After a call to xprt_reserve(), we must have either
 688          * a request slot or else an error status.
 689          */
 690         task->tk_status = 0;
 691         if (status >= 0) {
 692                 if (task->tk_rqstp) {
 693                         task->tk_action = call_allocate;
 694                         return;
 695                 }
 696
 697                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 698                                 __FUNCTION__, status);
 699                 rpc_exit(task, -EIO);
 700                 return;
 701         }
 702
 703         /*
 704          * Even though there was an error, we may have acquired
 705          * a request slot somehow.  Make sure not to leak it.
 706          */
 707         if (task->tk_rqstp) {
 708                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 709                                 __FUNCTION__, status);
 710                 xprt_release(task);
 711         }
 712
 713         switch (status) {
 714         case -EAGAIN:   /* woken up; retry */
 715                 task->tk_action = call_reserve;
 716                 return;
 717         case -EIO:      /* probably a shutdown */
 718                 break;
 719         default:
 720                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 721                                 __FUNCTION__, status);
 722                 break;
 723         }
 724         rpc_exit(task, status);
 725 }
 726
 727 /*
 728  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 729  *      (Note: buffer memory is freed in xprt_release).
 730  */
 731 static void
 732 call_allocate(struct rpc_task *task)
 733 {
 734         unsigned int slack = task->tk_auth->au_cslack;
 735         struct rpc_rqst *req = task->tk_rqstp;
 736         struct rpc_xprt *xprt = task->tk_xprt;
 737         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 738
 739         dprint_status(task);
 740
 741         task->tk_status = 0;
 742         task->tk_action = call_bind;
 743
 744         if (req->rq_buffer)
 745                 return;
 746
 747         if (proc->p_proc != 0) {
 748                 BUG_ON(proc->p_arglen == 0);
 749                 if (proc->p_decode != NULL)
 750                         BUG_ON(proc->p_replen == 0);
 751         }
 752
 753         /*
 754          * Calculate the size (in quads) of the RPC call
 755          * and reply headers, and convert both values
 756          * to byte sizes.
 757          */
 758         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
 759         req->rq_callsize <<= 2;
 760         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
 761         req->rq_rcvsize <<= 2;
 762
 763         req->rq_buffer = xprt->ops->buf_alloc(task,
 764                                         req->rq_callsize + req->rq_rcvsize);
 765         if (req->rq_buffer != NULL)
 766                 return;
 767
 768         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
 769
 770         if (RPC_IS_ASYNC(task) || !signalled()) {
 771                 xprt_release(task);
 772                 task->tk_action = call_reserve;
 773                 rpc_delay(task, HZ>>4);
 774                 return;
 775         }
 776
 777         rpc_exit(task, -ERESTARTSYS);
 778 }
 779
 780 static inline int
 781 rpc_task_need_encode(struct rpc_task *task)
 782 {
 783         return task->tk_rqstp->rq_snd_buf.len == 0;
 784 }
 785
 786 static inline void
 787 rpc_task_force_reencode(struct rpc_task *task)
 788 {
 789         task->tk_rqstp->rq_snd_buf.len = 0;
 790 }
 791
 792 static inline void
 793 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
 794 {
 795         buf->head[0].iov_base = start;
 796         buf->head[0].iov_len = len;
 797         buf->tail[0].iov_len = 0;
 798         buf->page_len = 0;
 799         buf->len = 0;
 800         buf->buflen = len;
 801 }
 802
 803 /*
 804  * 3.   Encode arguments of an RPC call
 805  */
 806 static void
 807 call_encode(struct rpc_task *task)
 808 {
 809         struct rpc_rqst *req = task->tk_rqstp;
 810         kxdrproc_t      encode;
 811         __be32          *p;
 812
 813         dprint_status(task);
 814
 815         rpc_xdr_buf_init(&req->rq_snd_buf,
 816                          req->rq_buffer,
 817                          req->rq_callsize);
 818         rpc_xdr_buf_init(&req->rq_rcv_buf,
 819                          (char *)req->rq_buffer + req->rq_callsize,
 820                          req->rq_rcvsize);
 821
 822         /* Encode header and provided arguments */
 823         encode = task->tk_msg.rpc_proc->p_encode;
 824         if (!(p = call_header(task))) {
 825                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 826                 rpc_exit(task, -EIO);
 827                 return;
 828         }
 829         if (encode == NULL)
 830                 return;
 831
 832         lock_kernel();
 833         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 834                         task->tk_msg.rpc_argp);
 835         unlock_kernel();
 836         if (task->tk_status == -ENOMEM) {
 837                 /* XXX: Is this sane? */
 838                 rpc_delay(task, 3*HZ);
 839                 task->tk_status = -EAGAIN;
 840         }
 841 }
 842
 843 /*
 844  * 4.   Get the server port number if not yet set
 845  */
 846 static void
 847 call_bind(struct rpc_task *task)
 848 {
 849         struct rpc_xprt *xprt = task->tk_xprt;
 850
 851         dprint_status(task);
 852
 853         task->tk_action = call_connect;
 854         if (!xprt_bound(xprt)) {
 855                 task->tk_action = call_bind_status;
 856                 task->tk_timeout = xprt->bind_timeout;
 857                 xprt->ops->rpcbind(task);
 858         }
 859 }
 860
 861 /*
 862  * 4a.  Sort out bind result
 863  */
 864 static void
 865 call_bind_status(struct rpc_task *task)
 866 {
 867         int status = -EACCES;
 868
 869         if (task->tk_status >= 0) {
 870                 dprint_status(task);
 871                 task->tk_status = 0;
 872                 task->tk_action = call_connect;
 873                 return;
 874         }
 875
 876         switch (task->tk_status) {
 877         case -EACCES:
 878                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
 879                                 "unavailable\n", task->tk_pid);
 880                 rpc_delay(task, 3*HZ);
 881                 goto retry_timeout;
 882         case -ETIMEDOUT:
 883                 dprintk("RPC: %5u rpcbind request timed out\n",
 884                                 task->tk_pid);
 885                 goto retry_timeout;
 886         case -EPFNOSUPPORT:
 887                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
 888                                 task->tk_pid);
 889                 break;
 890         case -EPROTONOSUPPORT:
 891                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
 892                                 task->tk_pid);
 893                 task->tk_status = 0;
 894                 task->tk_action = call_bind;
 895                 return;
 896         default:
 897                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 898                                 task->tk_pid, -task->tk_status);
 899                 status = -EIO;
 900         }
 901
 902         rpc_exit(task, status);
 903         return;
 904
 905 retry_timeout:
 906         task->tk_action = call_timeout;
 907 }
 908
 909 /*
 910  * 4b.  Connect to the RPC server
 911  */
 912 static void
 913 call_connect(struct rpc_task *task)
 914 {
 915         struct rpc_xprt *xprt = task->tk_xprt;
 916
 917         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
 918                         task->tk_pid, xprt,
 919                         (xprt_connected(xprt) ? "is" : "is not"));
 920
 921         task->tk_action = call_transmit;
 922         if (!xprt_connected(xprt)) {
 923                 task->tk_action = call_connect_status;
 924                 if (task->tk_status < 0)
 925                         return;
 926                 xprt_connect(task);
 927         }
 928 }
 929
 930 /*
 931  * 4c.  Sort out connect result
 932  */
 933 static void
 934 call_connect_status(struct rpc_task *task)
 935 {
 936         struct rpc_clnt *clnt = task->tk_client;
 937         int status = task->tk_status;
 938
 939         dprint_status(task);
 940
 941         task->tk_status = 0;
 942         if (status >= 0) {
 943                 clnt->cl_stats->netreconn++;
 944                 task->tk_action = call_transmit;
 945                 return;
 946         }
 947
 948         /* Something failed: remote service port may have changed */
 949         rpc_force_rebind(clnt);
 950
 951         switch (status) {
 952         case -ENOTCONN:
 953         case -EAGAIN:
 954                 task->tk_action = call_bind;
 955                 if (!RPC_IS_SOFT(task))
 956                         return;
 957                 /* if soft mounted, test if we've timed out */
 958         case -ETIMEDOUT:
 959                 task->tk_action = call_timeout;
 960                 return;
 961         }
 962         rpc_exit(task, -EIO);
 963 }
 964
 965 /*
 966  * 5.   Transmit the RPC request, and wait for reply
 967  */
 968 static void
 969 call_transmit(struct rpc_task *task)
 970 {
 971         dprint_status(task);
 972
 973         task->tk_action = call_status;
 974         if (task->tk_status < 0)
 975                 return;
 976         task->tk_status = xprt_prepare_transmit(task);
 977         if (task->tk_status != 0)
 978                 return;
 979         task->tk_action = call_transmit_status;
 980         /* Encode here so that rpcsec_gss can use correct sequence number. */
 981         if (rpc_task_need_encode(task)) {
 982                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 983                 call_encode(task);
 984                 /* Did the encode result in an error condition? */
 985                 if (task->tk_status != 0)
 986                         return;
 987         }
 988         xprt_transmit(task);
 989         if (task->tk_status < 0)
 990                 return;
 991         /*
 992          * On success, ensure that we call xprt_end_transmit() before sleeping
 993          * in order to allow access to the socket to other RPC requests.
 994          */
 995         call_transmit_status(task);
 996         if (task->tk_msg.rpc_proc->p_decode != NULL)
 997                 return;
 998         task->tk_action = rpc_exit_task;
 999         rpc_wake_up_task(task);
1000 }
1001
1002 /*
1003  * 5a.  Handle cleanup after a transmission
1004  */
1005 static void
1006 call_transmit_status(struct rpc_task *task)
1007 {
1008         task->tk_action = call_status;
1009         /*
1010          * Special case: if we've been waiting on the socket's write_space()
1011          * callback, then don't call xprt_end_transmit().
1012          */
1013         if (task->tk_status == -EAGAIN)
1014                 return;
1015         xprt_end_transmit(task);
1016         rpc_task_force_reencode(task);
1017 }
1018
1019 /*
1020  * 6.   Sort out the RPC call status
1021  */
1022 static void
1023 call_status(struct rpc_task *task)
1024 {
1025         struct rpc_clnt *clnt = task->tk_client;
1026         struct rpc_rqst *req = task->tk_rqstp;
1027         int             status;
1028
1029         if (req->rq_received > 0 && !req->rq_bytes_sent)
1030                 task->tk_status = req->rq_received;
1031
1032         dprint_status(task);
1033
1034         status = task->tk_status;
1035         if (status >= 0) {
1036                 task->tk_action = call_decode;
1037                 return;
1038         }
1039
1040         task->tk_status = 0;
1041         switch(status) {
1042         case -EHOSTDOWN:
1043         case -EHOSTUNREACH:
1044         case -ENETUNREACH:
1045                 /*
1046                  * Delay any retries for 3 seconds, then handle as if it
1047                  * were a timeout.
1048                  */
1049                 rpc_delay(task, 3*HZ);
1050         case -ETIMEDOUT:
1051                 task->tk_action = call_timeout;
1052                 if (task->tk_client->cl_discrtry)
1053                         xprt_disconnect(task->tk_xprt);
1054                 break;
1055         case -ECONNREFUSED:
1056         case -ENOTCONN:
1057                 rpc_force_rebind(clnt);
1058                 task->tk_action = call_bind;
1059                 break;
1060         case -EAGAIN:
1061                 task->tk_action = call_transmit;
1062                 break;
1063         case -EIO:
1064                 /* shutdown or soft timeout */
1065                 rpc_exit(task, status);
1066                 break;
1067         default:
1068                 printk("%s: RPC call returned error %d\n",
1069                                clnt->cl_protname, -status);
1070                 rpc_exit(task, status);
1071         }
1072 }
1073
1074 /*
1075  * 6a.  Handle RPC timeout
1076  *      We do not release the request slot, so we keep using the
1077  *      same XID for all retransmits.
1078  */
1079 static void
1080 call_timeout(struct rpc_task *task)
1081 {
1082         struct rpc_clnt *clnt = task->tk_client;
1083
1084         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1085                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1086                 goto retry;
1087         }
1088
1089         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1090         task->tk_timeouts++;
1091
1092         if (RPC_IS_SOFT(task)) {
1093                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1094                                 clnt->cl_protname, clnt->cl_server);
1095                 rpc_exit(task, -EIO);
1096                 return;
1097         }
1098
1099         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1100                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1101                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1102                         clnt->cl_protname, clnt->cl_server);
1103         }
1104         rpc_force_rebind(clnt);
1105
1106 retry:
1107         clnt->cl_stats->rpcretrans++;
1108         task->tk_action = call_bind;
1109         task->tk_status = 0;
1110 }
1111
1112 /*
1113  * 7.   Decode the RPC reply
1114  */
1115 static void
1116 call_decode(struct rpc_task *task)
1117 {
1118         struct rpc_clnt *clnt = task->tk_client;
1119         struct rpc_rqst *req = task->tk_rqstp;
1120         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1121         __be32          *p;
1122
1123         dprintk("RPC: %5u call_decode (status %d)\n",
1124                         task->tk_pid, task->tk_status);
1125
1126         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1127                 printk(KERN_NOTICE "%s: server %s OK\n",
1128                         clnt->cl_protname, clnt->cl_server);
1129                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1130         }
1131
1132         if (task->tk_status < 12) {
1133                 if (!RPC_IS_SOFT(task)) {
1134                         task->tk_action = call_bind;
1135                         clnt->cl_stats->rpcretrans++;
1136                         goto out_retry;
1137                 }
1138                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1139                                 clnt->cl_protname, task->tk_status);
1140                 task->tk_action = call_timeout;
1141                 goto out_retry;
1142         }
1143
1144         /*
1145          * Ensure that we see all writes made by xprt_complete_rqst()
1146          * before it changed req->rq_received.
1147          */
1148         smp_rmb();
1149         req->rq_rcv_buf.len = req->rq_private_buf.len;
1150
1151         /* Check that the softirq receive buffer is valid */
1152         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1153                                 sizeof(req->rq_rcv_buf)) != 0);
1154
1155         /* Verify the RPC header */
1156         p = call_verify(task);
1157         if (IS_ERR(p)) {
1158                 if (p == ERR_PTR(-EAGAIN))
1159                         goto out_retry;
1160                 return;
1161         }
1162
1163         task->tk_action = rpc_exit_task;
1164
1165         if (decode) {
1166                 lock_kernel();
1167                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1168                                                       task->tk_msg.rpc_resp);
1169                 unlock_kernel();
1170         }
1171         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1172                         task->tk_status);
1173         return;
1174 out_retry:
1175         req->rq_received = req->rq_private_buf.len = 0;
1176         task->tk_status = 0;
1177         if (task->tk_client->cl_discrtry)
1178                 xprt_disconnect(task->tk_xprt);
1179 }
1180
1181 /*
1182  * 8.   Refresh the credentials if rejected by the server
1183  */
1184 static void
1185 call_refresh(struct rpc_task *task)
1186 {
1187         dprint_status(task);
1188
1189         xprt_release(task);     /* Must do to obtain new XID */
1190         task->tk_action = call_refreshresult;
1191         task->tk_status = 0;
1192         task->tk_client->cl_stats->rpcauthrefresh++;
1193         rpcauth_refreshcred(task);
1194 }
1195
1196 /*
1197  * 8a.  Process the results of a credential refresh
1198  */
1199 static void
1200 call_refreshresult(struct rpc_task *task)
1201 {
1202         int status = task->tk_status;
1203
1204         dprint_status(task);
1205
1206         task->tk_status = 0;
1207         task->tk_action = call_reserve;
1208         if (status >= 0 && rpcauth_uptodatecred(task))
1209                 return;
1210         if (status == -EACCES) {
1211                 rpc_exit(task, -EACCES);
1212                 return;
1213         }
1214         task->tk_action = call_refresh;
1215         if (status != -ETIMEDOUT)
1216                 rpc_delay(task, 3*HZ);
1217         return;
1218 }
1219
1220 /*
1221  * Call header serialization
1222  */
1223 static __be32 *
1224 call_header(struct rpc_task *task)
1225 {
1226         struct rpc_clnt *clnt = task->tk_client;
1227         struct rpc_rqst *req = task->tk_rqstp;
1228         __be32          *p = req->rq_svec[0].iov_base;
1229
1230         /* FIXME: check buffer size? */
1231
1232         p = xprt_skip_transport_header(task->tk_xprt, p);
1233         *p++ = req->rq_xid;             /* XID */
1234         *p++ = htonl(RPC_CALL);         /* CALL */
1235         *p++ = htonl(RPC_VERSION);      /* RPC version */
1236         *p++ = htonl(clnt->cl_prog);    /* program number */
1237         *p++ = htonl(clnt->cl_vers);    /* program version */
1238         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1239         p = rpcauth_marshcred(task, p);
1240         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1241         return p;
1242 }
1243
1244 /*
1245  * Reply header verification
1246  */
1247 static __be32 *
1248 call_verify(struct rpc_task *task)
1249 {
1250         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1251         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1252         __be32  *p = iov->iov_base;
1253         u32 n;
1254         int error = -EACCES;
1255
1256         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1257                 /* RFC-1014 says that the representation of XDR data must be a
1258                  * multiple of four bytes
1259                  * - if it isn't pointer subtraction in the NFS client may give
1260                  *   undefined results
1261                  */
1262                 printk(KERN_WARNING
1263                        "call_verify: XDR representation not a multiple of"
1264                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1265                 goto out_eio;
1266         }
1267         if ((len -= 3) < 0)
1268                 goto out_overflow;
1269         p += 1; /* skip XID */
1270
1271         if ((n = ntohl(*p++)) != RPC_REPLY) {
1272                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1273                 goto out_garbage;
1274         }
1275         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1276                 if (--len < 0)
1277                         goto out_overflow;
1278                 switch ((n = ntohl(*p++))) {
1279                         case RPC_AUTH_ERROR:
1280                                 break;
1281                         case RPC_MISMATCH:
1282                                 dprintk("RPC: %5u %s: RPC call version "
1283                                                 "mismatch!\n",
1284                                                 task->tk_pid, __FUNCTION__);
1285                                 error = -EPROTONOSUPPORT;
1286                                 goto out_err;
1287                         default:
1288                                 dprintk("RPC: %5u %s: RPC call rejected, "
1289                                                 "unknown error: %x\n",
1290                                                 task->tk_pid, __FUNCTION__, n);
1291                                 goto out_eio;
1292                 }
1293                 if (--len < 0)
1294                         goto out_overflow;
1295                 switch ((n = ntohl(*p++))) {
1296                 case RPC_AUTH_REJECTEDCRED:
1297                 case RPC_AUTH_REJECTEDVERF:
1298                 case RPCSEC_GSS_CREDPROBLEM:
1299                 case RPCSEC_GSS_CTXPROBLEM:
1300                         if (!task->tk_cred_retry)
1301                                 break;
1302                         task->tk_cred_retry--;
1303                         dprintk("RPC: %5u %s: retry stale creds\n",
1304                                         task->tk_pid, __FUNCTION__);
1305                         rpcauth_invalcred(task);
1306                         task->tk_action = call_refresh;
1307                         goto out_retry;
1308                 case RPC_AUTH_BADCRED:
1309                 case RPC_AUTH_BADVERF:
1310                         /* possibly garbled cred/verf? */
1311                         if (!task->tk_garb_retry)
1312                                 break;
1313                         task->tk_garb_retry--;
1314                         dprintk("RPC: %5u %s: retry garbled creds\n",
1315                                         task->tk_pid, __FUNCTION__);
1316                         task->tk_action = call_bind;
1317                         goto out_retry;
1318                 case RPC_AUTH_TOOWEAK:
1319                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1320                                "authentication.\n", task->tk_client->cl_server);
1321                         break;
1322                 default:
1323                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1324                         error = -EIO;
1325                 }
1326                 dprintk("RPC: %5u %s: call rejected %d\n",
1327                                 task->tk_pid, __FUNCTION__, n);
1328                 goto out_err;
1329         }
1330         if (!(p = rpcauth_checkverf(task, p))) {
1331                 printk(KERN_WARNING "call_verify: auth check failed\n");
1332                 goto out_garbage;               /* bad verifier, retry */
1333         }
1334         len = p - (__be32 *)iov->iov_base - 1;
1335         if (len < 0)
1336                 goto out_overflow;
1337         switch ((n = ntohl(*p++))) {
1338         case RPC_SUCCESS:
1339                 return p;
1340         case RPC_PROG_UNAVAIL:
1341                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1342                                 task->tk_pid, __FUNCTION__,
1343                                 (unsigned int)task->tk_client->cl_prog,
1344                                 task->tk_client->cl_server);
1345                 error = -EPFNOSUPPORT;
1346                 goto out_err;
1347         case RPC_PROG_MISMATCH:
1348                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1349                                 "server %s\n", task->tk_pid, __FUNCTION__,
1350                                 (unsigned int)task->tk_client->cl_prog,
1351                                 (unsigned int)task->tk_client->cl_vers,
1352                                 task->tk_client->cl_server);
1353                 error = -EPROTONOSUPPORT;
1354                 goto out_err;
1355         case RPC_PROC_UNAVAIL:
1356                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1357                                 "version %u on server %s\n",
1358                                 task->tk_pid, __FUNCTION__,
1359                                 task->tk_msg.rpc_proc,
1360                                 task->tk_client->cl_prog,
1361                                 task->tk_client->cl_vers,
1362                                 task->tk_client->cl_server);
1363                 error = -EOPNOTSUPP;
1364                 goto out_err;
1365         case RPC_GARBAGE_ARGS:
1366                 dprintk("RPC: %5u %s: server saw garbage\n",
1367                                 task->tk_pid, __FUNCTION__);
1368                 break;                  /* retry */
1369         default:
1370                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1371                 /* Also retry */
1372         }
1373
1374 out_garbage:
1375         task->tk_client->cl_stats->rpcgarbage++;
1376         if (task->tk_garb_retry) {
1377                 task->tk_garb_retry--;
1378                 dprintk("RPC: %5u %s: retrying\n",
1379                                 task->tk_pid, __FUNCTION__);
1380                 task->tk_action = call_bind;
1381 out_retry:
1382                 return ERR_PTR(-EAGAIN);
1383         }
1384         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1385 out_eio:
1386         error = -EIO;
1387 out_err:
1388         rpc_exit(task, error);
1389         return ERR_PTR(error);
1390 out_overflow:
1391         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1392         goto out_garbage;
1393 }
1394
1395 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1396 {
1397         return 0;
1398 }
1399
1400 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1401 {
1402         return 0;
1403 }
1404
1405 static struct rpc_procinfo rpcproc_null = {
1406         .p_encode = rpcproc_encode_null,
1407         .p_decode = rpcproc_decode_null,
1408 };
1409
1410 int rpc_ping(struct rpc_clnt *clnt, int flags)
1411 {
1412         struct rpc_message msg = {
1413                 .rpc_proc = &rpcproc_null,
1414         };
1415         int err;
1416         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1417         err = rpc_call_sync(clnt, &msg, flags);
1418         put_rpccred(msg.rpc_cred);
1419         return err;
1420 }