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

   1 /*
   2  *  linux/net/sunrpc/clnt.c
   3  *
   4  *  This file contains the high-level RPC interface.
   5  *  It is modeled as a finite state machine to support both synchronous
   6  *  and asynchronous requests.
   7  *
   8  *  -   RPC header generation and argument serialization.
   9  *  -   Credential refresh.
  10  *  -   TCP connect handling.
  11  *  -   Retry of operation when it is suspected the operation failed because
  12  *      of uid squashing on the server, or when the credentials were stale
  13  *      and need to be refreshed, or when a packet was damaged in transit.
  14  *      This may be have to be moved to the VFS layer.
  15  *
  16  *  NB: BSD uses a more intelligent approach to guessing when a request
  17  *  or reply has been lost by keeping the RTO estimate for each procedure.
  18  *  We currently make do with a constant timeout value.
  19  *
  20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  22  */
  23
  24 #include <asm/system.h>
  25
  26 #include <linux/module.h>
  27 #include <linux/types.h>
  28 #include <linux/mm.h>
  29 #include <linux/slab.h>
  30 #include <linux/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_users, 0);
 125         atomic_set(&clnt->cl_count, 1);
 126         clnt->cl_parent = clnt;
 127
 128         clnt->cl_server = clnt->cl_inline_name;
 129         len = strlen(servname) + 1;
 130         if (len > sizeof(clnt->cl_inline_name)) {
 131                 char *buf = kmalloc(len, GFP_KERNEL);
 132                 if (buf != 0)
 133                         clnt->cl_server = buf;
 134                 else
 135                         len = sizeof(clnt->cl_inline_name);
 136         }
 137         strlcpy(clnt->cl_server, servname, len);
 138
 139         clnt->cl_xprt     = xprt;
 140         clnt->cl_procinfo = version->procs;
 141         clnt->cl_maxproc  = version->nrprocs;
 142         clnt->cl_protname = program->name;
 143         clnt->cl_prog     = program->number;
 144         clnt->cl_vers     = version->number;
 145         clnt->cl_stats    = program->stats;
 146         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 147         err = -ENOMEM;
 148         if (clnt->cl_metrics == NULL)
 149                 goto out_no_stats;
 150         clnt->cl_program  = program;
 151
 152         if (!xprt_bound(clnt->cl_xprt))
 153                 clnt->cl_autobind = 1;
 154
 155         clnt->cl_rtt = &clnt->cl_rtt_default;
 156         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
 157
 158         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 159         if (err < 0)
 160                 goto out_no_path;
 161
 162         auth = rpcauth_create(flavor, clnt);
 163         if (IS_ERR(auth)) {
 164                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 165                                 flavor);
 166                 err = PTR_ERR(auth);
 167                 goto out_no_auth;
 168         }
 169
 170         /* save the nodename */
 171         clnt->cl_nodelen = strlen(utsname()->nodename);
 172         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 173                 clnt->cl_nodelen = UNX_MAXNODENAME;
 174         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
 175         return clnt;
 176
 177 out_no_auth:
 178         if (!IS_ERR(clnt->cl_dentry)) {
 179                 rpc_rmdir(clnt->cl_dentry);
 180                 rpc_put_mount();
 181         }
 182 out_no_path:
 183         rpc_free_iostats(clnt->cl_metrics);
 184 out_no_stats:
 185         if (clnt->cl_server != clnt->cl_inline_name)
 186                 kfree(clnt->cl_server);
 187         kfree(clnt);
 188 out_err:
 189         xprt_put(xprt);
 190 out_no_xprt:
 191         return ERR_PTR(err);
 192 }
 193
 194 /*
 195  * rpc_create - create an RPC client and transport with one call
 196  * @args: rpc_clnt create argument structure
 197  *
 198  * Creates and initializes an RPC transport and an RPC client.
 199  *
 200  * It can ping the server in order to determine if it is up, and to see if
 201  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 202  * this behavior so asynchronous tasks can also use rpc_create.
 203  */
 204 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 205 {
 206         struct rpc_xprt *xprt;
 207         struct rpc_clnt *clnt;
 208
 209         xprt = xprt_create_transport(args->protocol, args->address,
 210                                         args->addrsize, args->timeout);
 211         if (IS_ERR(xprt))
 212                 return (struct rpc_clnt *)xprt;
 213
 214         /*
 215          * By default, kernel RPC client connects from a reserved port.
 216          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 217          * but it is always enabled for rpciod, which handles the connect
 218          * operation.
 219          */
 220         xprt->resvport = 1;
 221         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 222                 xprt->resvport = 0;
 223
 224         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 225                         args->program->name, args->servername, xprt);
 226
 227         clnt = rpc_new_client(xprt, args->servername, args->program,
 228                                 args->version, args->authflavor);
 229         if (IS_ERR(clnt))
 230                 return clnt;
 231
 232         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 233                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
 234                 if (err != 0) {
 235                         rpc_shutdown_client(clnt);
 236                         return ERR_PTR(err);
 237                 }
 238         }
 239
 240         clnt->cl_softrtry = 1;
 241         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 242                 clnt->cl_softrtry = 0;
 243
 244         if (args->flags & RPC_CLNT_CREATE_INTR)
 245                 clnt->cl_intr = 1;
 246         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 247                 clnt->cl_autobind = 1;
 248         if (args->flags & RPC_CLNT_CREATE_ONESHOT)
 249                 clnt->cl_oneshot = 1;
 250         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 251                 clnt->cl_discrtry = 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         unsigned int slack = task->tk_auth->au_cslack;
 749         struct rpc_rqst *req = task->tk_rqstp;
 750         struct rpc_xprt *xprt = task->tk_xprt;
 751         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 752
 753         dprint_status(task);
 754
 755         task->tk_status = 0;
 756         task->tk_action = call_bind;
 757
 758         if (req->rq_buffer)
 759                 return;
 760
 761         if (proc->p_proc != 0) {
 762                 BUG_ON(proc->p_arglen == 0);
 763                 if (proc->p_decode != NULL)
 764                         BUG_ON(proc->p_replen == 0);
 765         }
 766
 767         /*
 768          * Calculate the size (in quads) of the RPC call
 769          * and reply headers, and convert both values
 770          * to byte sizes.
 771          */
 772         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
 773         req->rq_callsize <<= 2;
 774         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
 775         req->rq_rcvsize <<= 2;
 776
 777         xprt->ops->buf_alloc(task, req->rq_callsize + req->rq_rcvsize);
 778         if (req->rq_buffer != NULL)
 779                 return;
 780
 781         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
 782
 783         if (RPC_IS_ASYNC(task) || !signalled()) {
 784                 xprt_release(task);
 785                 task->tk_action = call_reserve;
 786                 rpc_delay(task, HZ>>4);
 787                 return;
 788         }
 789
 790         rpc_exit(task, -ERESTARTSYS);
 791 }
 792
 793 static inline int
 794 rpc_task_need_encode(struct rpc_task *task)
 795 {
 796         return task->tk_rqstp->rq_snd_buf.len == 0;
 797 }
 798
 799 static inline void
 800 rpc_task_force_reencode(struct rpc_task *task)
 801 {
 802         task->tk_rqstp->rq_snd_buf.len = 0;
 803 }
 804
 805 static inline void
 806 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
 807 {
 808         buf->head[0].iov_base = start;
 809         buf->head[0].iov_len = len;
 810         buf->tail[0].iov_len = 0;
 811         buf->page_len = 0;
 812         buf->len = 0;
 813         buf->buflen = len;
 814 }
 815
 816 /*
 817  * 3.   Encode arguments of an RPC call
 818  */
 819 static void
 820 call_encode(struct rpc_task *task)
 821 {
 822         struct rpc_rqst *req = task->tk_rqstp;
 823         kxdrproc_t      encode;
 824         __be32          *p;
 825
 826         dprint_status(task);
 827
 828         rpc_xdr_buf_init(&req->rq_snd_buf,
 829                          req->rq_buffer,
 830                          req->rq_callsize);
 831         rpc_xdr_buf_init(&req->rq_rcv_buf,
 832                          (char *)req->rq_buffer + req->rq_callsize,
 833                          req->rq_rcvsize);
 834
 835         /* Encode header and provided arguments */
 836         encode = task->tk_msg.rpc_proc->p_encode;
 837         if (!(p = call_header(task))) {
 838                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
 839                 rpc_exit(task, -EIO);
 840                 return;
 841         }
 842         if (encode == NULL)
 843                 return;
 844
 845         lock_kernel();
 846         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
 847                         task->tk_msg.rpc_argp);
 848         unlock_kernel();
 849         if (task->tk_status == -ENOMEM) {
 850                 /* XXX: Is this sane? */
 851                 rpc_delay(task, 3*HZ);
 852                 task->tk_status = -EAGAIN;
 853         }
 854 }
 855
 856 /*
 857  * 4.   Get the server port number if not yet set
 858  */
 859 static void
 860 call_bind(struct rpc_task *task)
 861 {
 862         struct rpc_xprt *xprt = task->tk_xprt;
 863
 864         dprint_status(task);
 865
 866         task->tk_action = call_connect;
 867         if (!xprt_bound(xprt)) {
 868                 task->tk_action = call_bind_status;
 869                 task->tk_timeout = xprt->bind_timeout;
 870                 xprt->ops->rpcbind(task);
 871         }
 872 }
 873
 874 /*
 875  * 4a.  Sort out bind result
 876  */
 877 static void
 878 call_bind_status(struct rpc_task *task)
 879 {
 880         int status = -EACCES;
 881
 882         if (task->tk_status >= 0) {
 883                 dprint_status(task);
 884                 task->tk_status = 0;
 885                 task->tk_action = call_connect;
 886                 return;
 887         }
 888
 889         switch (task->tk_status) {
 890         case -EACCES:
 891                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
 892                                 "unavailable\n", task->tk_pid);
 893                 rpc_delay(task, 3*HZ);
 894                 goto retry_timeout;
 895         case -ETIMEDOUT:
 896                 dprintk("RPC: %5u rpcbind request timed out\n",
 897                                 task->tk_pid);
 898                 goto retry_timeout;
 899         case -EPFNOSUPPORT:
 900                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
 901                                 task->tk_pid);
 902                 break;
 903         case -EPROTONOSUPPORT:
 904                 dprintk("RPC: %5u remote rpcbind version 2 unavailable\n",
 905                                 task->tk_pid);
 906                 break;
 907         default:
 908                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
 909                                 task->tk_pid, -task->tk_status);
 910                 status = -EIO;
 911         }
 912
 913         rpc_exit(task, status);
 914         return;
 915
 916 retry_timeout:
 917         task->tk_action = call_timeout;
 918 }
 919
 920 /*
 921  * 4b.  Connect to the RPC server
 922  */
 923 static void
 924 call_connect(struct rpc_task *task)
 925 {
 926         struct rpc_xprt *xprt = task->tk_xprt;
 927
 928         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
 929                         task->tk_pid, xprt,
 930                         (xprt_connected(xprt) ? "is" : "is not"));
 931
 932         task->tk_action = call_transmit;
 933         if (!xprt_connected(xprt)) {
 934                 task->tk_action = call_connect_status;
 935                 if (task->tk_status < 0)
 936                         return;
 937                 xprt_connect(task);
 938         }
 939 }
 940
 941 /*
 942  * 4c.  Sort out connect result
 943  */
 944 static void
 945 call_connect_status(struct rpc_task *task)
 946 {
 947         struct rpc_clnt *clnt = task->tk_client;
 948         int status = task->tk_status;
 949
 950         dprint_status(task);
 951
 952         task->tk_status = 0;
 953         if (status >= 0) {
 954                 clnt->cl_stats->netreconn++;
 955                 task->tk_action = call_transmit;
 956                 return;
 957         }
 958
 959         /* Something failed: remote service port may have changed */
 960         rpc_force_rebind(clnt);
 961
 962         switch (status) {
 963         case -ENOTCONN:
 964         case -EAGAIN:
 965                 task->tk_action = call_bind;
 966                 if (!RPC_IS_SOFT(task))
 967                         return;
 968                 /* if soft mounted, test if we've timed out */
 969         case -ETIMEDOUT:
 970                 task->tk_action = call_timeout;
 971                 return;
 972         }
 973         rpc_exit(task, -EIO);
 974 }
 975
 976 /*
 977  * 5.   Transmit the RPC request, and wait for reply
 978  */
 979 static void
 980 call_transmit(struct rpc_task *task)
 981 {
 982         dprint_status(task);
 983
 984         task->tk_action = call_status;
 985         if (task->tk_status < 0)
 986                 return;
 987         task->tk_status = xprt_prepare_transmit(task);
 988         if (task->tk_status != 0)
 989                 return;
 990         task->tk_action = call_transmit_status;
 991         /* Encode here so that rpcsec_gss can use correct sequence number. */
 992         if (rpc_task_need_encode(task)) {
 993                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
 994                 call_encode(task);
 995                 /* Did the encode result in an error condition? */
 996                 if (task->tk_status != 0)
 997                         return;
 998         }
 999         xprt_transmit(task);
1000         if (task->tk_status < 0)
1001                 return;
1002         /*
1003          * On success, ensure that we call xprt_end_transmit() before sleeping
1004          * in order to allow access to the socket to other RPC requests.
1005          */
1006         call_transmit_status(task);
1007         if (task->tk_msg.rpc_proc->p_decode != NULL)
1008                 return;
1009         task->tk_action = rpc_exit_task;
1010         rpc_wake_up_task(task);
1011 }
1012
1013 /*
1014  * 5a.  Handle cleanup after a transmission
1015  */
1016 static void
1017 call_transmit_status(struct rpc_task *task)
1018 {
1019         task->tk_action = call_status;
1020         /*
1021          * Special case: if we've been waiting on the socket's write_space()
1022          * callback, then don't call xprt_end_transmit().
1023          */
1024         if (task->tk_status == -EAGAIN)
1025                 return;
1026         xprt_end_transmit(task);
1027         rpc_task_force_reencode(task);
1028 }
1029
1030 /*
1031  * 6.   Sort out the RPC call status
1032  */
1033 static void
1034 call_status(struct rpc_task *task)
1035 {
1036         struct rpc_clnt *clnt = task->tk_client;
1037         struct rpc_rqst *req = task->tk_rqstp;
1038         int             status;
1039
1040         if (req->rq_received > 0 && !req->rq_bytes_sent)
1041                 task->tk_status = req->rq_received;
1042
1043         dprint_status(task);
1044
1045         status = task->tk_status;
1046         if (status >= 0) {
1047                 task->tk_action = call_decode;
1048                 return;
1049         }
1050
1051         task->tk_status = 0;
1052         switch(status) {
1053         case -EHOSTDOWN:
1054         case -EHOSTUNREACH:
1055         case -ENETUNREACH:
1056                 /*
1057                  * Delay any retries for 3 seconds, then handle as if it
1058                  * were a timeout.
1059                  */
1060                 rpc_delay(task, 3*HZ);
1061         case -ETIMEDOUT:
1062                 task->tk_action = call_timeout;
1063                 if (task->tk_client->cl_discrtry)
1064                         xprt_disconnect(task->tk_xprt);
1065                 break;
1066         case -ECONNREFUSED:
1067         case -ENOTCONN:
1068                 rpc_force_rebind(clnt);
1069                 task->tk_action = call_bind;
1070                 break;
1071         case -EAGAIN:
1072                 task->tk_action = call_transmit;
1073                 break;
1074         case -EIO:
1075                 /* shutdown or soft timeout */
1076                 rpc_exit(task, status);
1077                 break;
1078         default:
1079                 printk("%s: RPC call returned error %d\n",
1080                                clnt->cl_protname, -status);
1081                 rpc_exit(task, status);
1082         }
1083 }
1084
1085 /*
1086  * 6a.  Handle RPC timeout
1087  *      We do not release the request slot, so we keep using the
1088  *      same XID for all retransmits.
1089  */
1090 static void
1091 call_timeout(struct rpc_task *task)
1092 {
1093         struct rpc_clnt *clnt = task->tk_client;
1094
1095         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1096                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1097                 goto retry;
1098         }
1099
1100         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1101         task->tk_timeouts++;
1102
1103         if (RPC_IS_SOFT(task)) {
1104                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1105                                 clnt->cl_protname, clnt->cl_server);
1106                 rpc_exit(task, -EIO);
1107                 return;
1108         }
1109
1110         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1111                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1112                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1113                         clnt->cl_protname, clnt->cl_server);
1114         }
1115         rpc_force_rebind(clnt);
1116
1117 retry:
1118         clnt->cl_stats->rpcretrans++;
1119         task->tk_action = call_bind;
1120         task->tk_status = 0;
1121 }
1122
1123 /*
1124  * 7.   Decode the RPC reply
1125  */
1126 static void
1127 call_decode(struct rpc_task *task)
1128 {
1129         struct rpc_clnt *clnt = task->tk_client;
1130         struct rpc_rqst *req = task->tk_rqstp;
1131         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1132         __be32          *p;
1133
1134         dprintk("RPC: %5u call_decode (status %d)\n",
1135                         task->tk_pid, task->tk_status);
1136
1137         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1138                 printk(KERN_NOTICE "%s: server %s OK\n",
1139                         clnt->cl_protname, clnt->cl_server);
1140                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1141         }
1142
1143         if (task->tk_status < 12) {
1144                 if (!RPC_IS_SOFT(task)) {
1145                         task->tk_action = call_bind;
1146                         clnt->cl_stats->rpcretrans++;
1147                         goto out_retry;
1148                 }
1149                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1150                                 clnt->cl_protname, task->tk_status);
1151                 task->tk_action = call_timeout;
1152                 goto out_retry;
1153         }
1154
1155         /*
1156          * Ensure that we see all writes made by xprt_complete_rqst()
1157          * before it changed req->rq_received.
1158          */
1159         smp_rmb();
1160         req->rq_rcv_buf.len = req->rq_private_buf.len;
1161
1162         /* Check that the softirq receive buffer is valid */
1163         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1164                                 sizeof(req->rq_rcv_buf)) != 0);
1165
1166         /* Verify the RPC header */
1167         p = call_verify(task);
1168         if (IS_ERR(p)) {
1169                 if (p == ERR_PTR(-EAGAIN))
1170                         goto out_retry;
1171                 return;
1172         }
1173
1174         task->tk_action = rpc_exit_task;
1175
1176         if (decode) {
1177                 lock_kernel();
1178                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1179                                                       task->tk_msg.rpc_resp);
1180                 unlock_kernel();
1181         }
1182         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1183                         task->tk_status);
1184         return;
1185 out_retry:
1186         req->rq_received = req->rq_private_buf.len = 0;
1187         task->tk_status = 0;
1188         if (task->tk_client->cl_discrtry)
1189                 xprt_disconnect(task->tk_xprt);
1190 }
1191
1192 /*
1193  * 8.   Refresh the credentials if rejected by the server
1194  */
1195 static void
1196 call_refresh(struct rpc_task *task)
1197 {
1198         dprint_status(task);
1199
1200         xprt_release(task);     /* Must do to obtain new XID */
1201         task->tk_action = call_refreshresult;
1202         task->tk_status = 0;
1203         task->tk_client->cl_stats->rpcauthrefresh++;
1204         rpcauth_refreshcred(task);
1205 }
1206
1207 /*
1208  * 8a.  Process the results of a credential refresh
1209  */
1210 static void
1211 call_refreshresult(struct rpc_task *task)
1212 {
1213         int status = task->tk_status;
1214
1215         dprint_status(task);
1216
1217         task->tk_status = 0;
1218         task->tk_action = call_reserve;
1219         if (status >= 0 && rpcauth_uptodatecred(task))
1220                 return;
1221         if (status == -EACCES) {
1222                 rpc_exit(task, -EACCES);
1223                 return;
1224         }
1225         task->tk_action = call_refresh;
1226         if (status != -ETIMEDOUT)
1227                 rpc_delay(task, 3*HZ);
1228         return;
1229 }
1230
1231 /*
1232  * Call header serialization
1233  */
1234 static __be32 *
1235 call_header(struct rpc_task *task)
1236 {
1237         struct rpc_clnt *clnt = task->tk_client;
1238         struct rpc_rqst *req = task->tk_rqstp;
1239         __be32          *p = req->rq_svec[0].iov_base;
1240
1241         /* FIXME: check buffer size? */
1242
1243         p = xprt_skip_transport_header(task->tk_xprt, p);
1244         *p++ = req->rq_xid;             /* XID */
1245         *p++ = htonl(RPC_CALL);         /* CALL */
1246         *p++ = htonl(RPC_VERSION);      /* RPC version */
1247         *p++ = htonl(clnt->cl_prog);    /* program number */
1248         *p++ = htonl(clnt->cl_vers);    /* program version */
1249         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1250         p = rpcauth_marshcred(task, p);
1251         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1252         return p;
1253 }
1254
1255 /*
1256  * Reply header verification
1257  */
1258 static __be32 *
1259 call_verify(struct rpc_task *task)
1260 {
1261         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1262         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1263         __be32  *p = iov->iov_base;
1264         u32 n;
1265         int error = -EACCES;
1266
1267         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1268                 /* RFC-1014 says that the representation of XDR data must be a
1269                  * multiple of four bytes
1270                  * - if it isn't pointer subtraction in the NFS client may give
1271                  *   undefined results
1272                  */
1273                 printk(KERN_WARNING
1274                        "call_verify: XDR representation not a multiple of"
1275                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1276                 goto out_eio;
1277         }
1278         if ((len -= 3) < 0)
1279                 goto out_overflow;
1280         p += 1; /* skip XID */
1281
1282         if ((n = ntohl(*p++)) != RPC_REPLY) {
1283                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1284                 goto out_garbage;
1285         }
1286         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1287                 if (--len < 0)
1288                         goto out_overflow;
1289                 switch ((n = ntohl(*p++))) {
1290                         case RPC_AUTH_ERROR:
1291                                 break;
1292                         case RPC_MISMATCH:
1293                                 dprintk("RPC: %5u %s: RPC call version "
1294                                                 "mismatch!\n",
1295                                                 task->tk_pid, __FUNCTION__);
1296                                 error = -EPROTONOSUPPORT;
1297                                 goto out_err;
1298                         default:
1299                                 dprintk("RPC: %5u %s: RPC call rejected, "
1300                                                 "unknown error: %x\n",
1301                                                 task->tk_pid, __FUNCTION__, n);
1302                                 goto out_eio;
1303                 }
1304                 if (--len < 0)
1305                         goto out_overflow;
1306                 switch ((n = ntohl(*p++))) {
1307                 case RPC_AUTH_REJECTEDCRED:
1308                 case RPC_AUTH_REJECTEDVERF:
1309                 case RPCSEC_GSS_CREDPROBLEM:
1310                 case RPCSEC_GSS_CTXPROBLEM:
1311                         if (!task->tk_cred_retry)
1312                                 break;
1313                         task->tk_cred_retry--;
1314                         dprintk("RPC: %5u %s: retry stale creds\n",
1315                                         task->tk_pid, __FUNCTION__);
1316                         rpcauth_invalcred(task);
1317                         task->tk_action = call_refresh;
1318                         goto out_retry;
1319                 case RPC_AUTH_BADCRED:
1320                 case RPC_AUTH_BADVERF:
1321                         /* possibly garbled cred/verf? */
1322                         if (!task->tk_garb_retry)
1323                                 break;
1324                         task->tk_garb_retry--;
1325                         dprintk("RPC: %5u %s: retry garbled creds\n",
1326                                         task->tk_pid, __FUNCTION__);
1327                         task->tk_action = call_bind;
1328                         goto out_retry;
1329                 case RPC_AUTH_TOOWEAK:
1330                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1331                                "authentication.\n", task->tk_client->cl_server);
1332                         break;
1333                 default:
1334                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1335                         error = -EIO;
1336                 }
1337                 dprintk("RPC: %5u %s: call rejected %d\n",
1338                                 task->tk_pid, __FUNCTION__, n);
1339                 goto out_err;
1340         }
1341         if (!(p = rpcauth_checkverf(task, p))) {
1342                 printk(KERN_WARNING "call_verify: auth check failed\n");
1343                 goto out_garbage;               /* bad verifier, retry */
1344         }
1345         len = p - (__be32 *)iov->iov_base - 1;
1346         if (len < 0)
1347                 goto out_overflow;
1348         switch ((n = ntohl(*p++))) {
1349         case RPC_SUCCESS:
1350                 return p;
1351         case RPC_PROG_UNAVAIL:
1352                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1353                                 task->tk_pid, __FUNCTION__,
1354                                 (unsigned int)task->tk_client->cl_prog,
1355                                 task->tk_client->cl_server);
1356                 error = -EPFNOSUPPORT;
1357                 goto out_err;
1358         case RPC_PROG_MISMATCH:
1359                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1360                                 "server %s\n", task->tk_pid, __FUNCTION__,
1361                                 (unsigned int)task->tk_client->cl_prog,
1362                                 (unsigned int)task->tk_client->cl_vers,
1363                                 task->tk_client->cl_server);
1364                 error = -EPROTONOSUPPORT;
1365                 goto out_err;
1366         case RPC_PROC_UNAVAIL:
1367                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1368                                 "version %u on server %s\n",
1369                                 task->tk_pid, __FUNCTION__,
1370                                 task->tk_msg.rpc_proc,
1371                                 task->tk_client->cl_prog,
1372                                 task->tk_client->cl_vers,
1373                                 task->tk_client->cl_server);
1374                 error = -EOPNOTSUPP;
1375                 goto out_err;
1376         case RPC_GARBAGE_ARGS:
1377                 dprintk("RPC: %5u %s: server saw garbage\n",
1378                                 task->tk_pid, __FUNCTION__);
1379                 break;                  /* retry */
1380         default:
1381                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1382                 /* Also retry */
1383         }
1384
1385 out_garbage:
1386         task->tk_client->cl_stats->rpcgarbage++;
1387         if (task->tk_garb_retry) {
1388                 task->tk_garb_retry--;
1389                 dprintk("RPC: %5u %s: retrying\n",
1390                                 task->tk_pid, __FUNCTION__);
1391                 task->tk_action = call_bind;
1392 out_retry:
1393                 return ERR_PTR(-EAGAIN);
1394         }
1395         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1396 out_eio:
1397         error = -EIO;
1398 out_err:
1399         rpc_exit(task, error);
1400         return ERR_PTR(error);
1401 out_overflow:
1402         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1403         goto out_garbage;
1404 }
1405
1406 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1407 {
1408         return 0;
1409 }
1410
1411 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1412 {
1413         return 0;
1414 }
1415
1416 static struct rpc_procinfo rpcproc_null = {
1417         .p_encode = rpcproc_encode_null,
1418         .p_decode = rpcproc_decode_null,
1419 };
1420
1421 int rpc_ping(struct rpc_clnt *clnt, int flags)
1422 {
1423         struct rpc_message msg = {
1424                 .rpc_proc = &rpcproc_null,
1425         };
1426         int err;
1427         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1428         err = rpc_call_sync(clnt, &msg, flags);
1429         put_rpccred(msg.rpc_cred);
1430         return err;
1431 }