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   1 /*
   2  *  linux/net/sunrpc/clnt.c
   3  *
   4  *  This file contains the high-level RPC interface.
   5  *  It is modeled as a finite state machine to support both synchronous
   6  *  and asynchronous requests.
   7  *
   8  *  -   RPC header generation and argument serialization.
   9  *  -   Credential refresh.
  10  *  -   TCP connect handling.
  11  *  -   Retry of operation when it is suspected the operation failed because
  12  *      of uid squashing on the server, or when the credentials were stale
  13  *      and need to be refreshed, or when a packet was damaged in transit.
  14  *      This may be have to be moved to the VFS layer.
  15  *
  16  *  NB: BSD uses a more intelligent approach to guessing when a request
  17  *  or reply has been lost by keeping the RTO estimate for each procedure.
  18  *  We currently make do with a constant timeout value.
  19  *
  20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  22  */
  23
  24 #include <asm/system.h>
  25
  26 #include <linux/module.h>
  27 #include <linux/types.h>
  28 #include <linux/mm.h>
  29 #include <linux/slab.h>
  30 #include <linux/smp_lock.h>
  31 #include <linux/utsname.h>
  32 #include <linux/workqueue.h>
  33
  34 #include <linux/sunrpc/clnt.h>
  35 #include <linux/sunrpc/rpc_pipe_fs.h>
  36 #include <linux/sunrpc/metrics.h>
  37
  38
  39 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
  40
  41 #ifdef RPC_DEBUG
  42 # define RPCDBG_FACILITY        RPCDBG_CALL
  43 #endif
  44
  45 #define dprint_status(t)                                        \
  46         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  47                         __FUNCTION__, t->tk_status)
  48
  49 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  50
  51
  52 static void     call_start(struct rpc_task *task);
  53 static void     call_reserve(struct rpc_task *task);
  54 static void     call_reserveresult(struct rpc_task *task);
  55 static void     call_allocate(struct rpc_task *task);
  56 static void     call_encode(struct rpc_task *task);
  57 static void     call_decode(struct rpc_task *task);
  58 static void     call_bind(struct rpc_task *task);
  59 static void     call_bind_status(struct rpc_task *task);
  60 static void     call_transmit(struct rpc_task *task);
  61 static void     call_status(struct rpc_task *task);
  62 static void     call_transmit_status(struct rpc_task *task);
  63 static void     call_refresh(struct rpc_task *task);
  64 static void     call_refreshresult(struct rpc_task *task);
  65 static void     call_timeout(struct rpc_task *task);
  66 static void     call_connect(struct rpc_task *task);
  67 static void     call_connect_status(struct rpc_task *task);
  68 static __be32 * call_header(struct rpc_task *task);
  69 static __be32 * call_verify(struct rpc_task *task);
  70
  71
  72 static int
  73 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  74 {
  75         static uint32_t clntid;
  76         int error;
  77
  78         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
  79         clnt->cl_dentry = ERR_PTR(-ENOENT);
  80         if (dir_name == NULL)
  81                 return 0;
  82
  83         clnt->cl_vfsmnt = rpc_get_mount();
  84         if (IS_ERR(clnt->cl_vfsmnt))
  85                 return PTR_ERR(clnt->cl_vfsmnt);
  86
  87         for (;;) {
  88                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
  89                                 "%s/clnt%x", dir_name,
  90                                 (unsigned int)clntid++);
  91                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
  92                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
  93                 if (!IS_ERR(clnt->cl_dentry))
  94                         return 0;
  95                 error = PTR_ERR(clnt->cl_dentry);
  96                 if (error != -EEXIST) {
  97                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
  98                                         clnt->cl_pathname, error);
  99                         rpc_put_mount();
 100                         return error;
 101                 }
 102         }
 103 }
 104
 105 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
 106 {
 107         struct rpc_version      *version;
 108         struct rpc_clnt         *clnt = NULL;
 109         struct rpc_auth         *auth;
 110         int err;
 111         int len;
 112
 113         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 114                         program->name, servname, xprt);
 115
 116         err = -EINVAL;
 117         if (!xprt)
 118                 goto out_no_xprt;
 119         if (vers >= program->nrvers || !(version = program->version[vers]))
 120                 goto out_err;
 121
 122         err = -ENOMEM;
 123         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 124         if (!clnt)
 125                 goto out_err;
 126         atomic_set(&clnt->cl_users, 0);
 127         atomic_set(&clnt->cl_count, 1);
 128         clnt->cl_parent = clnt;
 129
 130         clnt->cl_server = clnt->cl_inline_name;
 131         len = strlen(servname) + 1;
 132         if (len > sizeof(clnt->cl_inline_name)) {
 133                 char *buf = kmalloc(len, GFP_KERNEL);
 134                 if (buf != 0)
 135                         clnt->cl_server = buf;
 136                 else
 137                         len = sizeof(clnt->cl_inline_name);
 138         }
 139         strlcpy(clnt->cl_server, servname, len);
 140
 141         clnt->cl_xprt     = xprt;
 142         clnt->cl_procinfo = version->procs;
 143         clnt->cl_maxproc  = version->nrprocs;
 144         clnt->cl_protname = program->name;
 145         clnt->cl_prog     = program->number;
 146         clnt->cl_vers     = version->number;
 147         clnt->cl_stats    = program->stats;
 148         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 149         err = -ENOMEM;
 150         if (clnt->cl_metrics == NULL)
 151                 goto out_no_stats;
 152         clnt->cl_program  = program;
 153
 154         if (!xprt_bound(clnt->cl_xprt))
 155                 clnt->cl_autobind = 1;
 156
 157         clnt->cl_rtt = &clnt->cl_rtt_default;
 158         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 159
 160         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 161         if (err < 0)
 162                 goto out_no_path;
 163
 164         auth = rpcauth_create(flavor, clnt);
 165         if (IS_ERR(auth)) {
 166                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 167                                 flavor);
 168                 err = PTR_ERR(auth);
 169                 goto out_no_auth;
 170         }
 171
 172         /* save the nodename */
 173         clnt->cl_nodelen = strlen(utsname()->nodename);
 174         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 175                 clnt->cl_nodelen = UNX_MAXNODENAME;
 176         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 177         return clnt;
 178
 179 out_no_auth:
 180         if (!IS_ERR(clnt->cl_dentry)) {
 181                 rpc_rmdir(clnt->cl_dentry);
 182                 rpc_put_mount();
 183         }
 184 out_no_path:
 185         rpc_free_iostats(clnt->cl_metrics);
 186 out_no_stats:
 187         if (clnt->cl_server != clnt->cl_inline_name)
 188                 kfree(clnt->cl_server);
 189         kfree(clnt);
 190 out_err:
 191         xprt_put(xprt);
 192 out_no_xprt:
 193         return ERR_PTR(err);
 194 }
 195
 196 /*
 197  * rpc_create - create an RPC client and transport with one call
 198  * @args: rpc_clnt create argument structure
 199  *
 200  * Creates and initializes an RPC transport and an RPC client.
 201  *
 202  * It can ping the server in order to determine if it is up, and to see if
 203  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 204  * this behavior so asynchronous tasks can also use rpc_create.
 205  */
 206 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 207 {
 208         struct rpc_xprt *xprt;
 209         struct rpc_clnt *clnt;
 210
 211         xprt = xprt_create_transport(args->protocol, args->address,
 212                                         args->addrsize, args->timeout);
 213         if (IS_ERR(xprt))
 214                 return (struct rpc_clnt *)xprt;
 215
 216         /*
 217          * By default, kernel RPC client connects from a reserved port.
 218          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 219          * but it is always enabled for rpciod, which handles the connect
 220          * operation.
 221          */
 222         xprt->resvport = 1;
 223         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 224                 xprt->resvport = 0;
 225
 226         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 227                         args->program->name, args->servername, xprt);
 228
 229         clnt = rpc_new_client(xprt, args->servername, args->program,
 230                                 args->version, args->authflavor);
 231         if (IS_ERR(clnt))
 232                 return clnt;
 233
 234         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 235                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 236                 if (err != 0) {
 237                         rpc_shutdown_client(clnt);
 238                         return ERR_PTR(err);
 239                 }
 240         }
 241
 242         clnt->cl_softrtry = 1;
 243         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 244                 clnt->cl_softrtry = 0;
 245
 246         if (args->flags & RPC_CLNT_CREATE_INTR)
 247                 clnt->cl_intr = 1;
 248         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 249                 clnt->cl_autobind = 1;
 250         if (args->flags & RPC_CLNT_CREATE_ONESHOT)
 251                 clnt->cl_oneshot = 1;
 252
 253         return clnt;
 254 }
 255 EXPORT_SYMBOL_GPL(rpc_create);
 256
 257 /*
 258  * This function clones the RPC client structure. It allows us to share the
 259  * same transport while varying parameters such as the authentication
 260  * flavour.
 261  */
 262 struct rpc_clnt *
 263 rpc_clone_client(struct rpc_clnt *clnt)
 264 {
 265         struct rpc_clnt *new;
 266         int err = -ENOMEM;
 267
 268         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 269         if (!new)
 270                 goto out_no_clnt;
 271         atomic_set(&new->cl_count, 1);
 272         atomic_set(&new->cl_users, 0);
 273         new->cl_metrics = rpc_alloc_iostats(clnt);
 274         if (new->cl_metrics == NULL)
 275                 goto out_no_stats;
 276         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 277         if (err != 0)
 278                 goto out_no_path;
 279         new->cl_parent = clnt;
 280         atomic_inc(&clnt->cl_count);
 281         new->cl_xprt = xprt_get(clnt->cl_xprt);
 282         /* Turn off autobind on clones */
 283         new->cl_autobind = 0;
 284         new->cl_oneshot = 0;
 285         new->cl_dead = 0;
 286         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
 287         if (new->cl_auth)
 288                 atomic_inc(&new->cl_auth->au_count);
 289         return new;
 290 out_no_path:
 291         rpc_free_iostats(new->cl_metrics);
 292 out_no_stats:
 293         kfree(new);
 294 out_no_clnt:
 295         dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
 296         return ERR_PTR(err);
 297 }
 298
 299 /*
 300  * Properly shut down an RPC client, terminating all outstanding
 301  * requests. Note that we must be certain that cl_oneshot and
 302  * cl_dead are cleared, or else the client would be destroyed
 303  * when the last task releases it.
 304  */
 305 int
 306 rpc_shutdown_client(struct rpc_clnt *clnt)
 307 {
 308         dprintk("RPC:       shutting down %s client for %s, tasks=%d\n",
 309                         clnt->cl_protname, clnt->cl_server,
 310                         atomic_read(&clnt->cl_users));
 311
 312         while (atomic_read(&clnt->cl_users) > 0) {
 313                 /* Don't let rpc_release_client destroy us */
 314                 clnt->cl_oneshot = 0;
 315                 clnt->cl_dead = 0;
 316                 rpc_killall_tasks(clnt);
 317                 wait_event_timeout(destroy_wait,
 318                         !atomic_read(&clnt->cl_users), 1*HZ);
 319         }
 320
 321         if (atomic_read(&clnt->cl_users) < 0) {
 322                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
 323                                 clnt, atomic_read(&clnt->cl_users));
 324 #ifdef RPC_DEBUG
 325                 rpc_show_tasks();
 326 #endif
 327                 BUG();
 328         }
 329
 330         return rpc_destroy_client(clnt);
 331 }
 332
 333 /*
 334  * Delete an RPC client
 335  */
 336 int
 337 rpc_destroy_client(struct rpc_clnt *clnt)
 338 {
 339         if (!atomic_dec_and_test(&clnt->cl_count))
 340                 return 1;
 341         BUG_ON(atomic_read(&clnt->cl_users) != 0);
 342
 343         dprintk("RPC:       destroying %s client for %s\n",
 344                         clnt->cl_protname, clnt->cl_server);
 345         if (clnt->cl_auth) {
 346                 rpcauth_destroy(clnt->cl_auth);
 347                 clnt->cl_auth = NULL;
 348         }
 349         if (!IS_ERR(clnt->cl_dentry)) {
 350                 rpc_rmdir(clnt->cl_dentry);
 351                 rpc_put_mount();
 352         }
 353         if (clnt->cl_parent != clnt) {
 354                 rpc_destroy_client(clnt->cl_parent);
 355                 goto out_free;
 356         }
 357         if (clnt->cl_server != clnt->cl_inline_name)
 358                 kfree(clnt->cl_server);
 359 out_free:
 360         rpc_free_iostats(clnt->cl_metrics);
 361         clnt->cl_metrics = NULL;
 362         xprt_put(clnt->cl_xprt);
 363         kfree(clnt);
 364         return 0;
 365 }
 366
 367 /*
 368  * Release an RPC client
 369  */
 370 void
 371 rpc_release_client(struct rpc_clnt *clnt)
 372 {
 373         dprintk("RPC:       rpc_release_client(%p, %d)\n",
 374                         clnt, atomic_read(&clnt->cl_users));
 375
 376         if (!atomic_dec_and_test(&clnt->cl_users))
 377                 return;
 378         wake_up(&destroy_wait);
 379         if (clnt->cl_oneshot || clnt->cl_dead)
 380                 rpc_destroy_client(clnt);
 381 }
 382
 383 /**
 384  * rpc_bind_new_program - bind a new RPC program to an existing client
 385  * @old - old rpc_client
 386  * @program - rpc program to set
 387  * @vers - rpc program version
 388  *
 389  * Clones the rpc client and sets up a new RPC program. This is mainly
 390  * of use for enabling different RPC programs to share the same transport.
 391  * The Sun NFSv2/v3 ACL protocol can do this.
 392  */
 393 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 394                                       struct rpc_program *program,
 395                                       int vers)
 396 {
 397         struct rpc_clnt *clnt;
 398         struct rpc_version *version;
 399         int err;
 400
 401         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 402         version = program->version[vers];
 403         clnt = rpc_clone_client(old);
 404         if (IS_ERR(clnt))
 405                 goto out;
 406         clnt->cl_procinfo = version->procs;
 407         clnt->cl_maxproc  = version->nrprocs;
 408         clnt->cl_protname = program->name;
 409         clnt->cl_prog     = program->number;
 410         clnt->cl_vers     = version->number;
 411         clnt->cl_stats    = program->stats;
 412         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 413         if (err != 0) {
 414                 rpc_shutdown_client(clnt);
 415                 clnt = ERR_PTR(err);
 416         }
 417 out:
 418         return clnt;
 419 }
 420
 421 /*
 422  * Default callback for async RPC calls
 423  */
 424 static void
 425 rpc_default_callback(struct rpc_task *task, void *data)
 426 {
 427 }
 428
 429 static const struct rpc_call_ops rpc_default_ops = {
 430         .rpc_call_done = rpc_default_callback,
 431 };
 432
 433 /*
 434  *      Export the signal mask handling for synchronous code that
 435  *      sleeps on RPC calls
 436  */
 437 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
 438
 439 static void rpc_save_sigmask(sigset_t *oldset, int intr)
 440 {
 441         unsigned long   sigallow = sigmask(SIGKILL);
 442         sigset_t sigmask;
 443
 444         /* Block all signals except those listed in sigallow */
 445         if (intr)
 446                 sigallow |= RPC_INTR_SIGNALS;
 447         siginitsetinv(&sigmask, sigallow);
 448         sigprocmask(SIG_BLOCK, &sigmask, oldset);
 449 }
 450
 451 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
 452 {
 453         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
 454 }
 455
 456 static inline void rpc_restore_sigmask(sigset_t *oldset)
 457 {
 458         sigprocmask(SIG_SETMASK, oldset, NULL);
 459 }
 460
 461 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
 462 {
 463         rpc_save_sigmask(oldset, clnt->cl_intr);
 464 }
 465
 466 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
 467 {
 468         rpc_restore_sigmask(oldset);
 469 }
 470
 471 /*
 472  * New rpc_call implementation
 473  */
 474 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
 475 {
 476         struct rpc_task *task;
 477         sigset_t        oldset;
 478         int             status;
 479
 480         /* If this client is slain all further I/O fails */
 481         if (clnt->cl_dead)
 482                 return -EIO;
 483
 484         BUG_ON(flags & RPC_TASK_ASYNC);
 485
 486         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
 487         if (task == NULL)
 488                 return -ENOMEM;
 489
 490         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
 491         rpc_task_sigmask(task, &oldset);
 492
 493         /* Set up the call info struct and execute the task */
 494         rpc_call_setup(task, msg, 0);
 495         if (task->tk_status == 0) {
 496                 atomic_inc(&task->tk_count);
 497                 rpc_execute(task);
 498         }
 499         status = task->tk_status;
 500         rpc_put_task(task);
 501         rpc_restore_sigmask(&oldset);
 502         return status;
 503 }
 504
 505 /*
 506  * New rpc_call implementation
 507  */
 508 int
 509 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
 510                const struct rpc_call_ops *tk_ops, void *data)
 511 {
 512         struct rpc_task *task;
 513         sigset_t        oldset;
 514         int             status;
 515
 516         /* If this client is slain all further I/O fails */
 517         status = -EIO;
 518         if (clnt->cl_dead)
 519                 goto out_release;
 520
 521         flags |= RPC_TASK_ASYNC;
 522
 523         /* Create/initialize a new RPC task */
 524         status = -ENOMEM;
 525         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
 526                 goto out_release;
 527
 528         /* Mask signals on GSS_AUTH upcalls */
 529         rpc_task_sigmask(task, &oldset);
 530
 531         rpc_call_setup(task, msg, 0);
 532
 533         /* Set up the call info struct and execute the task */
 534         status = task->tk_status;
 535         if (status == 0)
 536                 rpc_execute(task);
 537         else
 538                 rpc_put_task(task);
 539
 540         rpc_restore_sigmask(&oldset);
 541         return status;
 542 out_release:
 543         rpc_release_calldata(tk_ops, data);
 544         return status;
 545 }
 546
 547
 548 void
 549 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
 550 {
 551         task->tk_msg   = *msg;
 552         task->tk_flags |= flags;
 553         /* Bind the user cred */
 554         if (task->tk_msg.rpc_cred != NULL)
 555                 rpcauth_holdcred(task);
 556         else
 557                 rpcauth_bindcred(task);
 558
 559         if (task->tk_status == 0)
 560                 task->tk_action = call_start;
 561         else
 562                 task->tk_action = rpc_exit_task;
 563 }
 564
 565 /**
 566  * rpc_peeraddr - extract remote peer address from clnt's xprt
 567  * @clnt: RPC client structure
 568  * @buf: target buffer
 569  * @size: length of target buffer
 570  *
 571  * Returns the number of bytes that are actually in the stored address.
 572  */
 573 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 574 {
 575         size_t bytes;
 576         struct rpc_xprt *xprt = clnt->cl_xprt;
 577
 578         bytes = sizeof(xprt->addr);
 579         if (bytes > bufsize)
 580                 bytes = bufsize;
 581         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 582         return xprt->addrlen;
 583 }
 584 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 585
 586 /**
 587  * rpc_peeraddr2str - return remote peer address in printable format
 588  * @clnt: RPC client structure
 589  * @format: address format
 590  *
 591  */
 592 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
 593 {
 594         struct rpc_xprt *xprt = clnt->cl_xprt;
 595
 596         if (xprt->address_strings[format] != NULL)
 597                 return xprt->address_strings[format];
 598         else
 599                 return "unprintable";
 600 }
 601 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 602
 603 void
 604 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 605 {
 606         struct rpc_xprt *xprt = clnt->cl_xprt;
 607         if (xprt->ops->set_buffer_size)
 608                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 609 }
 610
 611 /*
 612  * Return size of largest payload RPC client can support, in bytes
 613  *
 614  * For stream transports, this is one RPC record fragment (see RFC
 615  * 1831), as we don't support multi-record requests yet.  For datagram
 616  * transports, this is the size of an IP packet minus the IP, UDP, and
 617  * RPC header sizes.
 618  */
 619 size_t rpc_max_payload(struct rpc_clnt *clnt)
 620 {
 621         return clnt->cl_xprt->max_payload;
 622 }
 623 EXPORT_SYMBOL_GPL(rpc_max_payload);
 624
 625 /**
 626  * rpc_force_rebind - force transport to check that remote port is unchanged
 627  * @clnt: client to rebind
 628  *
 629  */
 630 void rpc_force_rebind(struct rpc_clnt *clnt)
 631 {
 632         if (clnt->cl_autobind)
 633                 xprt_clear_bound(clnt->cl_xprt);
 634 }
 635 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 636
 637 /*
 638  * Restart an (async) RPC call. Usually called from within the
 639  * exit handler.
 640  */
 641 void
 642 rpc_restart_call(struct rpc_task *task)
 643 {
 644         if (RPC_ASSASSINATED(task))
 645                 return;
 646
 647         task->tk_action = call_start;
 648 }
 649
 650 /*
 651  * 0.  Initial state
 652  *
 653  *     Other FSM states can be visited zero or more times, but
 654  *     this state is visited exactly once for each RPC.
 655  */
 656 static void
 657 call_start(struct rpc_task *task)
 658 {
 659         struct rpc_clnt *clnt = task->tk_client;
 660
 661         dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
 662                         clnt->cl_protname, clnt->cl_vers,
 663                         task->tk_msg.rpc_proc->p_proc,
 664                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 665
 666         /* Increment call count */
 667         task->tk_msg.rpc_proc->p_count++;
 668         clnt->cl_stats->rpccnt++;
 669         task->tk_action = call_reserve;
 670 }
 671
 672 /*
 673  * 1.   Reserve an RPC call slot
 674  */
 675 static void
 676 call_reserve(struct rpc_task *task)
 677 {
 678         dprint_status(task);
 679
 680         if (!rpcauth_uptodatecred(task)) {
 681                 task->tk_action = call_refresh;
 682                 return;
 683         }
 684
 685         task->tk_status  = 0;
 686         task->tk_action  = call_reserveresult;
 687         xprt_reserve(task);
 688 }
 689
 690 /*
 691  * 1b.  Grok the result of xprt_reserve()
 692  */
 693 static void
 694 call_reserveresult(struct rpc_task *task)
 695 {
 696         int status = task->tk_status;
 697
 698         dprint_status(task);
 699
 700         /*
 701          * After a call to xprt_reserve(), we must have either
 702          * a request slot or else an error status.
 703          */
 704         task->tk_status = 0;
 705         if (status >= 0) {
 706                 if (task->tk_rqstp) {
 707                         task->tk_action = call_allocate;
 708                         return;
 709                 }
 710
 711                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 712                                 __FUNCTION__, status);
 713                 rpc_exit(task, -EIO);
 714                 return;
 715         }
 716
 717         /*
 718          * Even though there was an error, we may have acquired
 719          * a request slot somehow.  Make sure not to leak it.
 720          */
 721         if (task->tk_rqstp) {
 722                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 723                                 __FUNCTION__, status);
 724                 xprt_release(task);
 725         }
 726
 727         switch (status) {
 728         case -EAGAIN:   /* woken up; retry */
 729                 task->tk_action = call_reserve;
 730                 return;
 731         case -EIO:      /* probably a shutdown */
 732                 break;
 733         default:
 734                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 735                                 __FUNCTION__, status);
 736                 break;
 737         }
 738         rpc_exit(task, status);
 739 }
 740
 741 /*
 742  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
 743  *      (Note: buffer memory is freed in xprt_release).
 744  */
 745 static void
 746 call_allocate(struct rpc_task *task)
 747 {
 748         struct rpc_rqst *req = task->tk_rqstp;
 749         struct rpc_xprt *xprt = task->tk_xprt;
 750         unsigned int    bufsiz;
 751
 752         dprint_status(task);
 753
 754         task->tk_action = call_bind;
 755         if (req->rq_buffer)
 756                 return;
 757
 758         /* FIXME: compute buffer requirements more exactly using
 759          * auth->au_wslack */
 760         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
 761
 762         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
 763                 return;
 764
 765         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
 766
 767         if (RPC_IS_ASYNC(task) || !signalled()) {
 768                 xprt_release(task);
 769                 task->tk_action = call_reserve;
 770                 rpc_delay(task, HZ>>4);
 771                 return;
 772         }
 773
 774         rpc_exit(task, -ERESTARTSYS);
 775 }
 776
 777 static inline int
 778 rpc_task_need_encode(struct rpc_task *task)
 779 {
 780         return task->tk_rqstp->rq_snd_buf.len == 0;
 781 }
 782
 783 static inline void
 784 rpc_task_force_reencode(struct rpc_task *task)
 785 {
 786         task->tk_rqstp->rq_snd_buf.len = 0;
 787 }
 788
 789 /*
 790  * 3.   Encode arguments of an RPC call
 791  */
 792 static void
 793 call_encode(struct rpc_task *task)
 794 {
 795         struct rpc_rqst *req = task->tk_rqstp;
 796         struct xdr_buf *sndbuf = &req->rq_snd_buf;
 797         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
 798         unsigned int    bufsiz;
 799         kxdrproc_t      encode;
 800         __be32          *p;
 801
 802         dprint_status(task);
 803
 804         /* Default buffer setup */
 805         bufsiz = req->rq_bufsize >> 1;
 806         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
 807         sndbuf->head[0].iov_len  = bufsiz;
 808         sndbuf->tail[0].iov_len  = 0;
 809         sndbuf->page_len         = 0;
 810         sndbuf->len              = 0;
 811         sndbuf->buflen           = bufsiz;
 812         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
 813         rcvbuf->head[0].iov_len  = bufsiz;
 814         rcvbuf->tail[0].iov_len  = 0;
 815         rcvbuf->page_len         = 0;
 816         rcvbuf->len              = 0;
 817         rcvbuf->buflen           = bufsiz;
 818
 819         /* Encode header and provided arguments */
 820         encode = task->tk_msg.rpc_proc->p_encode;
 821         if (!(p = call_header(task))) {
 822                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 823                 rpc_exit(task, -EIO);
 824                 return;
 825         }
 826         if (encode == NULL)
 827                 return;
 828
 829         lock_kernel();
 830         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 831                         task->tk_msg.rpc_argp);
 832         unlock_kernel();
 833         if (task->tk_status == -ENOMEM) {
 834                 /* XXX: Is this sane? */
 835                 rpc_delay(task, 3*HZ);
 836                 task->tk_status = -EAGAIN;
 837         }
 838 }
 839
 840 /*
 841  * 4.   Get the server port number if not yet set
 842  */
 843 static void
 844 call_bind(struct rpc_task *task)
 845 {
 846         struct rpc_xprt *xprt = task->tk_xprt;
 847
 848         dprint_status(task);
 849
 850         task->tk_action = call_connect;
 851         if (!xprt_bound(xprt)) {
 852                 task->tk_action = call_bind_status;
 853                 task->tk_timeout = xprt->bind_timeout;
 854                 xprt->ops->rpcbind(task);
 855         }
 856 }
 857
 858 /*
 859  * 4a.  Sort out bind result
 860  */
 861 static void
 862 call_bind_status(struct rpc_task *task)
 863 {
 864         int status = -EACCES;
 865
 866         if (task->tk_status >= 0) {
 867                 dprint_status(task);
 868                 task->tk_status = 0;
 869                 task->tk_action = call_connect;
 870                 return;
 871         }
 872
 873         switch (task->tk_status) {
 874         case -EACCES:
 875                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
 876                                 "unavailable\n", task->tk_pid);
 877                 rpc_delay(task, 3*HZ);
 878                 goto retry_timeout;
 879         case -ETIMEDOUT:
 880                 dprintk("RPC: %5u rpcbind request timed out\n",
 881                                 task->tk_pid);
 882                 goto retry_timeout;
 883         case -EPFNOSUPPORT:
 884                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
 885                                 task->tk_pid);
 886                 break;
 887         case -EPROTONOSUPPORT:
 888                 dprintk("RPC: %5u remote rpcbind version 2 unavailable\n",
 889                                 task->tk_pid);
 890                 break;
 891         default:
 892                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 893                                 task->tk_pid, -task->tk_status);
 894                 status = -EIO;
 895         }
 896
 897         rpc_exit(task, status);
 898         return;
 899
 900 retry_timeout:
 901         task->tk_action = call_timeout;
 902 }
 903
 904 /*
 905  * 4b.  Connect to the RPC server
 906  */
 907 static void
 908 call_connect(struct rpc_task *task)
 909 {
 910         struct rpc_xprt *xprt = task->tk_xprt;
 911
 912         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
 913                         task->tk_pid, xprt,
 914                         (xprt_connected(xprt) ? "is" : "is not"));
 915
 916         task->tk_action = call_transmit;
 917         if (!xprt_connected(xprt)) {
 918                 task->tk_action = call_connect_status;
 919                 if (task->tk_status < 0)
 920                         return;
 921                 xprt_connect(task);
 922         }
 923 }
 924
 925 /*
 926  * 4c.  Sort out connect result
 927  */
 928 static void
 929 call_connect_status(struct rpc_task *task)
 930 {
 931         struct rpc_clnt *clnt = task->tk_client;
 932         int status = task->tk_status;
 933
 934         dprint_status(task);
 935
 936         task->tk_status = 0;
 937         if (status >= 0) {
 938                 clnt->cl_stats->netreconn++;
 939                 task->tk_action = call_transmit;
 940                 return;
 941         }
 942
 943         /* Something failed: remote service port may have changed */
 944         rpc_force_rebind(clnt);
 945
 946         switch (status) {
 947         case -ENOTCONN:
 948         case -EAGAIN:
 949                 task->tk_action = call_bind;
 950                 if (!RPC_IS_SOFT(task))
 951                         return;
 952                 /* if soft mounted, test if we've timed out */
 953         case -ETIMEDOUT:
 954                 task->tk_action = call_timeout;
 955                 return;
 956         }
 957         rpc_exit(task, -EIO);
 958 }
 959
 960 /*
 961  * 5.   Transmit the RPC request, and wait for reply
 962  */
 963 static void
 964 call_transmit(struct rpc_task *task)
 965 {
 966         dprint_status(task);
 967
 968         task->tk_action = call_status;
 969         if (task->tk_status < 0)
 970                 return;
 971         task->tk_status = xprt_prepare_transmit(task);
 972         if (task->tk_status != 0)
 973                 return;
 974         task->tk_action = call_transmit_status;
 975         /* Encode here so that rpcsec_gss can use correct sequence number. */
 976         if (rpc_task_need_encode(task)) {
 977                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 978                 call_encode(task);
 979                 /* Did the encode result in an error condition? */
 980                 if (task->tk_status != 0)
 981                         return;
 982         }
 983         xprt_transmit(task);
 984         if (task->tk_status < 0)
 985                 return;
 986         /*
 987          * On success, ensure that we call xprt_end_transmit() before sleeping
 988          * in order to allow access to the socket to other RPC requests.
 989          */
 990         call_transmit_status(task);
 991         if (task->tk_msg.rpc_proc->p_decode != NULL)
 992                 return;
 993         task->tk_action = rpc_exit_task;
 994         rpc_wake_up_task(task);
 995 }
 996
 997 /*
 998  * 5a.  Handle cleanup after a transmission
 999  */
1000 static void
1001 call_transmit_status(struct rpc_task *task)
1002 {
1003         task->tk_action = call_status;
1004         /*
1005          * Special case: if we've been waiting on the socket's write_space()
1006          * callback, then don't call xprt_end_transmit().
1007          */
1008         if (task->tk_status == -EAGAIN)
1009                 return;
1010         xprt_end_transmit(task);
1011         rpc_task_force_reencode(task);
1012 }
1013
1014 /*
1015  * 6.   Sort out the RPC call status
1016  */
1017 static void
1018 call_status(struct rpc_task *task)
1019 {
1020         struct rpc_clnt *clnt = task->tk_client;
1021         struct rpc_rqst *req = task->tk_rqstp;
1022         int             status;
1023
1024         if (req->rq_received > 0 && !req->rq_bytes_sent)
1025                 task->tk_status = req->rq_received;
1026
1027         dprint_status(task);
1028
1029         status = task->tk_status;
1030         if (status >= 0) {
1031                 task->tk_action = call_decode;
1032                 return;
1033         }
1034
1035         task->tk_status = 0;
1036         switch(status) {
1037         case -EHOSTDOWN:
1038         case -EHOSTUNREACH:
1039         case -ENETUNREACH:
1040                 /*
1041                  * Delay any retries for 3 seconds, then handle as if it
1042                  * were a timeout.
1043                  */
1044                 rpc_delay(task, 3*HZ);
1045         case -ETIMEDOUT:
1046                 task->tk_action = call_timeout;
1047                 break;
1048         case -ECONNREFUSED:
1049         case -ENOTCONN:
1050                 rpc_force_rebind(clnt);
1051                 task->tk_action = call_bind;
1052                 break;
1053         case -EAGAIN:
1054                 task->tk_action = call_transmit;
1055                 break;
1056         case -EIO:
1057                 /* shutdown or soft timeout */
1058                 rpc_exit(task, status);
1059                 break;
1060         default:
1061                 printk("%s: RPC call returned error %d\n",
1062                                clnt->cl_protname, -status);
1063                 rpc_exit(task, status);
1064         }
1065 }
1066
1067 /*
1068  * 6a.  Handle RPC timeout
1069  *      We do not release the request slot, so we keep using the
1070  *      same XID for all retransmits.
1071  */
1072 static void
1073 call_timeout(struct rpc_task *task)
1074 {
1075         struct rpc_clnt *clnt = task->tk_client;
1076
1077         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1078                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1079                 goto retry;
1080         }
1081
1082         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1083         task->tk_timeouts++;
1084
1085         if (RPC_IS_SOFT(task)) {
1086                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1087                                 clnt->cl_protname, clnt->cl_server);
1088                 rpc_exit(task, -EIO);
1089                 return;
1090         }
1091
1092         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1093                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1094                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1095                         clnt->cl_protname, clnt->cl_server);
1096         }
1097         rpc_force_rebind(clnt);
1098
1099 retry:
1100         clnt->cl_stats->rpcretrans++;
1101         task->tk_action = call_bind;
1102         task->tk_status = 0;
1103 }
1104
1105 /*
1106  * 7.   Decode the RPC reply
1107  */
1108 static void
1109 call_decode(struct rpc_task *task)
1110 {
1111         struct rpc_clnt *clnt = task->tk_client;
1112         struct rpc_rqst *req = task->tk_rqstp;
1113         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1114         __be32          *p;
1115
1116         dprintk("RPC: %5u call_decode (status %d)\n",
1117                         task->tk_pid, task->tk_status);
1118
1119         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1120                 printk(KERN_NOTICE "%s: server %s OK\n",
1121                         clnt->cl_protname, clnt->cl_server);
1122                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1123         }
1124
1125         if (task->tk_status < 12) {
1126                 if (!RPC_IS_SOFT(task)) {
1127                         task->tk_action = call_bind;
1128                         clnt->cl_stats->rpcretrans++;
1129                         goto out_retry;
1130                 }
1131                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1132                                 clnt->cl_protname, task->tk_status);
1133                 task->tk_action = call_timeout;
1134                 goto out_retry;
1135         }
1136
1137         /*
1138          * Ensure that we see all writes made by xprt_complete_rqst()
1139          * before it changed req->rq_received.
1140          */
1141         smp_rmb();
1142         req->rq_rcv_buf.len = req->rq_private_buf.len;
1143
1144         /* Check that the softirq receive buffer is valid */
1145         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1146                                 sizeof(req->rq_rcv_buf)) != 0);
1147
1148         /* Verify the RPC header */
1149         p = call_verify(task);
1150         if (IS_ERR(p)) {
1151                 if (p == ERR_PTR(-EAGAIN))
1152                         goto out_retry;
1153                 return;
1154         }
1155
1156         task->tk_action = rpc_exit_task;
1157
1158         if (decode) {
1159                 lock_kernel();
1160                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1161                                                       task->tk_msg.rpc_resp);
1162                 unlock_kernel();
1163         }
1164         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1165                         task->tk_status);
1166         return;
1167 out_retry:
1168         req->rq_received = req->rq_private_buf.len = 0;
1169         task->tk_status = 0;
1170 }
1171
1172 /*
1173  * 8.   Refresh the credentials if rejected by the server
1174  */
1175 static void
1176 call_refresh(struct rpc_task *task)
1177 {
1178         dprint_status(task);
1179
1180         xprt_release(task);     /* Must do to obtain new XID */
1181         task->tk_action = call_refreshresult;
1182         task->tk_status = 0;
1183         task->tk_client->cl_stats->rpcauthrefresh++;
1184         rpcauth_refreshcred(task);
1185 }
1186
1187 /*
1188  * 8a.  Process the results of a credential refresh
1189  */
1190 static void
1191 call_refreshresult(struct rpc_task *task)
1192 {
1193         int status = task->tk_status;
1194
1195         dprint_status(task);
1196
1197         task->tk_status = 0;
1198         task->tk_action = call_reserve;
1199         if (status >= 0 && rpcauth_uptodatecred(task))
1200                 return;
1201         if (status == -EACCES) {
1202                 rpc_exit(task, -EACCES);
1203                 return;
1204         }
1205         task->tk_action = call_refresh;
1206         if (status != -ETIMEDOUT)
1207                 rpc_delay(task, 3*HZ);
1208         return;
1209 }
1210
1211 /*
1212  * Call header serialization
1213  */
1214 static __be32 *
1215 call_header(struct rpc_task *task)
1216 {
1217         struct rpc_clnt *clnt = task->tk_client;
1218         struct rpc_rqst *req = task->tk_rqstp;
1219         __be32          *p = req->rq_svec[0].iov_base;
1220
1221         /* FIXME: check buffer size? */
1222
1223         p = xprt_skip_transport_header(task->tk_xprt, p);
1224         *p++ = req->rq_xid;             /* XID */
1225         *p++ = htonl(RPC_CALL);         /* CALL */
1226         *p++ = htonl(RPC_VERSION);      /* RPC version */
1227         *p++ = htonl(clnt->cl_prog);    /* program number */
1228         *p++ = htonl(clnt->cl_vers);    /* program version */
1229         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1230         p = rpcauth_marshcred(task, p);
1231         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1232         return p;
1233 }
1234
1235 /*
1236  * Reply header verification
1237  */
1238 static __be32 *
1239 call_verify(struct rpc_task *task)
1240 {
1241         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1242         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1243         __be32  *p = iov->iov_base;
1244         u32 n;
1245         int error = -EACCES;
1246
1247         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1248                 /* RFC-1014 says that the representation of XDR data must be a
1249                  * multiple of four bytes
1250                  * - if it isn't pointer subtraction in the NFS client may give
1251                  *   undefined results
1252                  */
1253                 printk(KERN_WARNING
1254                        "call_verify: XDR representation not a multiple of"
1255                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1256                 goto out_eio;
1257         }
1258         if ((len -= 3) < 0)
1259                 goto out_overflow;
1260         p += 1; /* skip XID */
1261
1262         if ((n = ntohl(*p++)) != RPC_REPLY) {
1263                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1264                 goto out_garbage;
1265         }
1266         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1267                 if (--len < 0)
1268                         goto out_overflow;
1269                 switch ((n = ntohl(*p++))) {
1270                         case RPC_AUTH_ERROR:
1271                                 break;
1272                         case RPC_MISMATCH:
1273                                 dprintk("RPC: %5u %s: RPC call version "
1274                                                 "mismatch!\n",
1275                                                 task->tk_pid, __FUNCTION__);
1276                                 error = -EPROTONOSUPPORT;
1277                                 goto out_err;
1278                         default:
1279                                 dprintk("RPC: %5u %s: RPC call rejected, "
1280                                                 "unknown error: %x\n",
1281                                                 task->tk_pid, __FUNCTION__, n);
1282                                 goto out_eio;
1283                 }
1284                 if (--len < 0)
1285                         goto out_overflow;
1286                 switch ((n = ntohl(*p++))) {
1287                 case RPC_AUTH_REJECTEDCRED:
1288                 case RPC_AUTH_REJECTEDVERF:
1289                 case RPCSEC_GSS_CREDPROBLEM:
1290                 case RPCSEC_GSS_CTXPROBLEM:
1291                         if (!task->tk_cred_retry)
1292                                 break;
1293                         task->tk_cred_retry--;
1294                         dprintk("RPC: %5u %s: retry stale creds\n",
1295                                         task->tk_pid, __FUNCTION__);
1296                         rpcauth_invalcred(task);
1297                         task->tk_action = call_refresh;
1298                         goto out_retry;
1299                 case RPC_AUTH_BADCRED:
1300                 case RPC_AUTH_BADVERF:
1301                         /* possibly garbled cred/verf? */
1302                         if (!task->tk_garb_retry)
1303                                 break;
1304                         task->tk_garb_retry--;
1305                         dprintk("RPC: %5u %s: retry garbled creds\n",
1306                                         task->tk_pid, __FUNCTION__);
1307                         task->tk_action = call_bind;
1308                         goto out_retry;
1309                 case RPC_AUTH_TOOWEAK:
1310                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1311                                "authentication.\n", task->tk_client->cl_server);
1312                         break;
1313                 default:
1314                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1315                         error = -EIO;
1316                 }
1317                 dprintk("RPC: %5u %s: call rejected %d\n",
1318                                 task->tk_pid, __FUNCTION__, n);
1319                 goto out_err;
1320         }
1321         if (!(p = rpcauth_checkverf(task, p))) {
1322                 printk(KERN_WARNING "call_verify: auth check failed\n");
1323                 goto out_garbage;               /* bad verifier, retry */
1324         }
1325         len = p - (__be32 *)iov->iov_base - 1;
1326         if (len < 0)
1327                 goto out_overflow;
1328         switch ((n = ntohl(*p++))) {
1329         case RPC_SUCCESS:
1330                 return p;
1331         case RPC_PROG_UNAVAIL:
1332                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1333                                 task->tk_pid, __FUNCTION__,
1334                                 (unsigned int)task->tk_client->cl_prog,
1335                                 task->tk_client->cl_server);
1336                 error = -EPFNOSUPPORT;
1337                 goto out_err;
1338         case RPC_PROG_MISMATCH:
1339                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1340                                 "server %s\n", task->tk_pid, __FUNCTION__,
1341                                 (unsigned int)task->tk_client->cl_prog,
1342                                 (unsigned int)task->tk_client->cl_vers,
1343                                 task->tk_client->cl_server);
1344                 error = -EPROTONOSUPPORT;
1345                 goto out_err;
1346         case RPC_PROC_UNAVAIL:
1347                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1348                                 "version %u on server %s\n",
1349                                 task->tk_pid, __FUNCTION__,
1350                                 task->tk_msg.rpc_proc,
1351                                 task->tk_client->cl_prog,
1352                                 task->tk_client->cl_vers,
1353                                 task->tk_client->cl_server);
1354                 error = -EOPNOTSUPP;
1355                 goto out_err;
1356         case RPC_GARBAGE_ARGS:
1357                 dprintk("RPC: %5u %s: server saw garbage\n",
1358                                 task->tk_pid, __FUNCTION__);
1359                 break;                  /* retry */
1360         default:
1361                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1362                 /* Also retry */
1363         }
1364
1365 out_garbage:
1366         task->tk_client->cl_stats->rpcgarbage++;
1367         if (task->tk_garb_retry) {
1368                 task->tk_garb_retry--;
1369                 dprintk("RPC: %5u %s: retrying\n",
1370                                 task->tk_pid, __FUNCTION__);
1371                 task->tk_action = call_bind;
1372 out_retry:
1373                 return ERR_PTR(-EAGAIN);
1374         }
1375         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1376 out_eio:
1377         error = -EIO;
1378 out_err:
1379         rpc_exit(task, error);
1380         return ERR_PTR(error);
1381 out_overflow:
1382         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1383         goto out_garbage;
1384 }
1385
1386 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1387 {
1388         return 0;
1389 }
1390
1391 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1392 {
1393         return 0;
1394 }
1395
1396 static struct rpc_procinfo rpcproc_null = {
1397         .p_encode = rpcproc_encode_null,
1398         .p_decode = rpcproc_decode_null,
1399 };
1400
1401 int rpc_ping(struct rpc_clnt *clnt, int flags)
1402 {
1403         struct rpc_message msg = {
1404                 .rpc_proc = &rpcproc_null,
1405         };
1406         int err;
1407         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1408         err = rpc_call_sync(clnt, &msg, flags);
1409         put_rpccred(msg.rpc_cred);
1410         return err;
1411 }