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  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
  17  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
  18  */
  19
  20 #include <asm/system.h>
  21
  22 #include <linux/module.h>
  23 #include <linux/types.h>
  24 #include <linux/kallsyms.h>
  25 #include <linux/mm.h>
  26 #include <linux/namei.h>
  27 #include <linux/mount.h>
  28 #include <linux/slab.h>
  29 #include <linux/utsname.h>
  30 #include <linux/workqueue.h>
  31 #include <linux/in.h>
  32 #include <linux/in6.h>
  33 #include <linux/un.h>
  34
  35 #include <linux/sunrpc/clnt.h>
  36 #include <linux/sunrpc/rpc_pipe_fs.h>
  37 #include <linux/sunrpc/metrics.h>
  38 #include <linux/sunrpc/bc_xprt.h>
  39
  40 #include "sunrpc.h"
  41
  42 #ifdef RPC_DEBUG
  43 # define RPCDBG_FACILITY        RPCDBG_CALL
  44 #endif
  45
  46 #define dprint_status(t)                                        \
  47         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  48                         __func__, t->tk_status)
  49
  50 /*
  51  * All RPC clients are linked into this list
  52  */
  53 static LIST_HEAD(all_clients);
  54 static DEFINE_SPINLOCK(rpc_client_lock);
  55
  56 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  57
  58
  59 static void     call_start(struct rpc_task *task);
  60 static void     call_reserve(struct rpc_task *task);
  61 static void     call_reserveresult(struct rpc_task *task);
  62 static void     call_allocate(struct rpc_task *task);
  63 static void     call_decode(struct rpc_task *task);
  64 static void     call_bind(struct rpc_task *task);
  65 static void     call_bind_status(struct rpc_task *task);
  66 static void     call_transmit(struct rpc_task *task);
  67 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
  68 static void     call_bc_transmit(struct rpc_task *task);
  69 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
  70 static void     call_status(struct rpc_task *task);
  71 static void     call_transmit_status(struct rpc_task *task);
  72 static void     call_refresh(struct rpc_task *task);
  73 static void     call_refreshresult(struct rpc_task *task);
  74 static void     call_timeout(struct rpc_task *task);
  75 static void     call_connect(struct rpc_task *task);
  76 static void     call_connect_status(struct rpc_task *task);
  77
  78 static __be32   *rpc_encode_header(struct rpc_task *task);
  79 static __be32   *rpc_verify_header(struct rpc_task *task);
  80 static int      rpc_ping(struct rpc_clnt *clnt);
  81
  82 static void rpc_register_client(struct rpc_clnt *clnt)
  83 {
  84         spin_lock(&rpc_client_lock);
  85         list_add(&clnt->cl_clients, &all_clients);
  86         spin_unlock(&rpc_client_lock);
  87 }
  88
  89 static void rpc_unregister_client(struct rpc_clnt *clnt)
  90 {
  91         spin_lock(&rpc_client_lock);
  92         list_del(&clnt->cl_clients);
  93         spin_unlock(&rpc_client_lock);
  94 }
  95
  96 static int
  97 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
  98 {
  99         static uint32_t clntid;
 100         struct path path, dir;
 101         char name[15];
 102         struct qstr q = {
 103                 .name = name,
 104         };
 105         int error;
 106
 107         clnt->cl_path.mnt = ERR_PTR(-ENOENT);
 108         clnt->cl_path.dentry = ERR_PTR(-ENOENT);
 109         if (dir_name == NULL)
 110                 return 0;
 111
 112         path.mnt = rpc_get_mount();
 113         if (IS_ERR(path.mnt))
 114                 return PTR_ERR(path.mnt);
 115         error = vfs_path_lookup(path.mnt->mnt_root, path.mnt, dir_name, 0, &dir);
 116         if (error)
 117                 goto err;
 118
 119         for (;;) {
 120                 q.len = snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
 121                 name[sizeof(name) - 1] = '\0';
 122                 q.hash = full_name_hash(q.name, q.len);
 123                 path.dentry = rpc_create_client_dir(dir.dentry, &q, clnt);
 124                 if (!IS_ERR(path.dentry))
 125                         break;
 126                 error = PTR_ERR(path.dentry);
 127                 if (error != -EEXIST) {
 128                         printk(KERN_INFO "RPC: Couldn't create pipefs entry"
 129                                         " %s/%s, error %d\n",
 130                                         dir_name, name, error);
 131                         goto err_path_put;
 132                 }
 133         }
 134         path_put(&dir);
 135         clnt->cl_path = path;
 136         return 0;
 137 err_path_put:
 138         path_put(&dir);
 139 err:
 140         rpc_put_mount();
 141         return error;
 142 }
 143
 144 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
 145 {
 146         struct rpc_program      *program = args->program;
 147         struct rpc_version      *version;
 148         struct rpc_clnt         *clnt = NULL;
 149         struct rpc_auth         *auth;
 150         int err;
 151         size_t len;
 152
 153         /* sanity check the name before trying to print it */
 154         err = -EINVAL;
 155         len = strlen(args->servername);
 156         if (len > RPC_MAXNETNAMELEN)
 157                 goto out_no_rpciod;
 158         len++;
 159
 160         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 161                         program->name, args->servername, xprt);
 162
 163         err = rpciod_up();
 164         if (err)
 165                 goto out_no_rpciod;
 166         err = -EINVAL;
 167         if (!xprt)
 168                 goto out_no_xprt;
 169
 170         if (args->version >= program->nrvers)
 171                 goto out_err;
 172         version = program->version[args->version];
 173         if (version == NULL)
 174                 goto out_err;
 175
 176         err = -ENOMEM;
 177         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 178         if (!clnt)
 179                 goto out_err;
 180         clnt->cl_parent = clnt;
 181
 182         clnt->cl_server = clnt->cl_inline_name;
 183         if (len > sizeof(clnt->cl_inline_name)) {
 184                 char *buf = kmalloc(len, GFP_KERNEL);
 185                 if (buf != NULL)
 186                         clnt->cl_server = buf;
 187                 else
 188                         len = sizeof(clnt->cl_inline_name);
 189         }
 190         strlcpy(clnt->cl_server, args->servername, len);
 191
 192         clnt->cl_xprt     = xprt;
 193         clnt->cl_procinfo = version->procs;
 194         clnt->cl_maxproc  = version->nrprocs;
 195         clnt->cl_protname = program->name;
 196         clnt->cl_prog     = args->prognumber ? : program->number;
 197         clnt->cl_vers     = version->number;
 198         clnt->cl_stats    = program->stats;
 199         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 200         err = -ENOMEM;
 201         if (clnt->cl_metrics == NULL)
 202                 goto out_no_stats;
 203         clnt->cl_program  = program;
 204         INIT_LIST_HEAD(&clnt->cl_tasks);
 205         spin_lock_init(&clnt->cl_lock);
 206
 207         if (!xprt_bound(clnt->cl_xprt))
 208                 clnt->cl_autobind = 1;
 209
 210         clnt->cl_timeout = xprt->timeout;
 211         if (args->timeout != NULL) {
 212                 memcpy(&clnt->cl_timeout_default, args->timeout,
 213                                 sizeof(clnt->cl_timeout_default));
 214                 clnt->cl_timeout = &clnt->cl_timeout_default;
 215         }
 216
 217         clnt->cl_rtt = &clnt->cl_rtt_default;
 218         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
 219         clnt->cl_principal = NULL;
 220         if (args->client_name) {
 221                 clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
 222                 if (!clnt->cl_principal)
 223                         goto out_no_principal;
 224         }
 225
 226         atomic_set(&clnt->cl_count, 1);
 227
 228         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
 229         if (err < 0)
 230                 goto out_no_path;
 231
 232         auth = rpcauth_create(args->authflavor, clnt);
 233         if (IS_ERR(auth)) {
 234                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
 235                                 args->authflavor);
 236                 err = PTR_ERR(auth);
 237                 goto out_no_auth;
 238         }
 239
 240         /* save the nodename */
 241         clnt->cl_nodelen = strlen(init_utsname()->nodename);
 242         if (clnt->cl_nodelen > UNX_MAXNODENAME)
 243                 clnt->cl_nodelen = UNX_MAXNODENAME;
 244         memcpy(clnt->cl_nodename, init_utsname()->nodename, clnt->cl_nodelen);
 245         rpc_register_client(clnt);
 246         return clnt;
 247
 248 out_no_auth:
 249         if (!IS_ERR(clnt->cl_path.dentry)) {
 250                 rpc_remove_client_dir(clnt->cl_path.dentry);
 251                 rpc_put_mount();
 252         }
 253 out_no_path:
 254         kfree(clnt->cl_principal);
 255 out_no_principal:
 256         rpc_free_iostats(clnt->cl_metrics);
 257 out_no_stats:
 258         if (clnt->cl_server != clnt->cl_inline_name)
 259                 kfree(clnt->cl_server);
 260         kfree(clnt);
 261 out_err:
 262         xprt_put(xprt);
 263 out_no_xprt:
 264         rpciod_down();
 265 out_no_rpciod:
 266         return ERR_PTR(err);
 267 }
 268
 269 /*
 270  * rpc_create - create an RPC client and transport with one call
 271  * @args: rpc_clnt create argument structure
 272  *
 273  * Creates and initializes an RPC transport and an RPC client.
 274  *
 275  * It can ping the server in order to determine if it is up, and to see if
 276  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 277  * this behavior so asynchronous tasks can also use rpc_create.
 278  */
 279 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 280 {
 281         struct rpc_xprt *xprt;
 282         struct rpc_clnt *clnt;
 283         struct xprt_create xprtargs = {
 284                 .net = args->net,
 285                 .ident = args->protocol,
 286                 .srcaddr = args->saddress,
 287                 .dstaddr = args->address,
 288                 .addrlen = args->addrsize,
 289                 .bc_xprt = args->bc_xprt,
 290         };
 291         char servername[48];
 292
 293         /*
 294          * If the caller chooses not to specify a hostname, whip
 295          * up a string representation of the passed-in address.
 296          */
 297         if (args->servername == NULL) {
 298                 struct sockaddr_un *sun =
 299                                 (struct sockaddr_un *)args->address;
 300                 struct sockaddr_in *sin =
 301                                 (struct sockaddr_in *)args->address;
 302                 struct sockaddr_in6 *sin6 =
 303                                 (struct sockaddr_in6 *)args->address;
 304
 305                 servername[0] = '\0';
 306                 switch (args->address->sa_family) {
 307                 case AF_LOCAL:
 308                         snprintf(servername, sizeof(servername), "%s",
 309                                  sun->sun_path);
 310                         break;
 311                 case AF_INET:
 312                         snprintf(servername, sizeof(servername), "%pI4",
 313                                  &sin->sin_addr.s_addr);
 314                         break;
 315                 case AF_INET6:
 316                         snprintf(servername, sizeof(servername), "%pI6",
 317                                  &sin6->sin6_addr);
 318                         break;
 319                 default:
 320                         /* caller wants default server name, but
 321                          * address family isn't recognized. */
 322                         return ERR_PTR(-EINVAL);
 323                 }
 324                 args->servername = servername;
 325         }
 326
 327         xprt = xprt_create_transport(&xprtargs);
 328         if (IS_ERR(xprt))
 329                 return (struct rpc_clnt *)xprt;
 330
 331         /*
 332          * By default, kernel RPC client connects from a reserved port.
 333          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 334          * but it is always enabled for rpciod, which handles the connect
 335          * operation.
 336          */
 337         xprt->resvport = 1;
 338         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 339                 xprt->resvport = 0;
 340
 341         clnt = rpc_new_client(args, xprt);
 342         if (IS_ERR(clnt))
 343                 return clnt;
 344
 345         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 346                 int err = rpc_ping(clnt);
 347                 if (err != 0) {
 348                         rpc_shutdown_client(clnt);
 349                         return ERR_PTR(err);
 350                 }
 351         }
 352
 353         clnt->cl_softrtry = 1;
 354         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 355                 clnt->cl_softrtry = 0;
 356
 357         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 358                 clnt->cl_autobind = 1;
 359         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 360                 clnt->cl_discrtry = 1;
 361         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 362                 clnt->cl_chatty = 1;
 363
 364         return clnt;
 365 }
 366 EXPORT_SYMBOL_GPL(rpc_create);
 367
 368 /*
 369  * This function clones the RPC client structure. It allows us to share the
 370  * same transport while varying parameters such as the authentication
 371  * flavour.
 372  */
 373 struct rpc_clnt *
 374 rpc_clone_client(struct rpc_clnt *clnt)
 375 {
 376         struct rpc_clnt *new;
 377         int err = -ENOMEM;
 378
 379         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
 380         if (!new)
 381                 goto out_no_clnt;
 382         new->cl_parent = clnt;
 383         /* Turn off autobind on clones */
 384         new->cl_autobind = 0;
 385         INIT_LIST_HEAD(&new->cl_tasks);
 386         spin_lock_init(&new->cl_lock);
 387         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_timeout->to_initval);
 388         new->cl_metrics = rpc_alloc_iostats(clnt);
 389         if (new->cl_metrics == NULL)
 390                 goto out_no_stats;
 391         if (clnt->cl_principal) {
 392                 new->cl_principal = kstrdup(clnt->cl_principal, GFP_KERNEL);
 393                 if (new->cl_principal == NULL)
 394                         goto out_no_principal;
 395         }
 396         atomic_set(&new->cl_count, 1);
 397         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
 398         if (err != 0)
 399                 goto out_no_path;
 400         if (new->cl_auth)
 401                 atomic_inc(&new->cl_auth->au_count);
 402         xprt_get(clnt->cl_xprt);
 403         atomic_inc(&clnt->cl_count);
 404         rpc_register_client(new);
 405         rpciod_up();
 406         return new;
 407 out_no_path:
 408         kfree(new->cl_principal);
 409 out_no_principal:
 410         rpc_free_iostats(new->cl_metrics);
 411 out_no_stats:
 412         kfree(new);
 413 out_no_clnt:
 414         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 415         return ERR_PTR(err);
 416 }
 417 EXPORT_SYMBOL_GPL(rpc_clone_client);
 418
 419 /*
 420  * Kill all tasks for the given client.
 421  * XXX: kill their descendants as well?
 422  */
 423 void rpc_killall_tasks(struct rpc_clnt *clnt)
 424 {
 425         struct rpc_task *rovr;
 426
 427
 428         if (list_empty(&clnt->cl_tasks))
 429                 return;
 430         dprintk("RPC:       killing all tasks for client %p\n", clnt);
 431         /*
 432          * Spin lock all_tasks to prevent changes...
 433          */
 434         spin_lock(&clnt->cl_lock);
 435         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
 436                 if (!RPC_IS_ACTIVATED(rovr))
 437                         continue;
 438                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
 439                         rovr->tk_flags |= RPC_TASK_KILLED;
 440                         rpc_exit(rovr, -EIO);
 441                         if (RPC_IS_QUEUED(rovr))
 442                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
 443                                                         rovr);
 444                 }
 445         }
 446         spin_unlock(&clnt->cl_lock);
 447 }
 448 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
 449
 450 /*
 451  * Properly shut down an RPC client, terminating all outstanding
 452  * requests.
 453  */
 454 void rpc_shutdown_client(struct rpc_clnt *clnt)
 455 {
 456         dprintk("RPC:       shutting down %s client for %s\n",
 457                         clnt->cl_protname, clnt->cl_server);
 458
 459         while (!list_empty(&clnt->cl_tasks)) {
 460                 rpc_killall_tasks(clnt);
 461                 wait_event_timeout(destroy_wait,
 462                         list_empty(&clnt->cl_tasks), 1*HZ);
 463         }
 464
 465         rpc_release_client(clnt);
 466 }
 467 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 468
 469 /*
 470  * Free an RPC client
 471  */
 472 static void
 473 rpc_free_client(struct rpc_clnt *clnt)
 474 {
 475         dprintk("RPC:       destroying %s client for %s\n",
 476                         clnt->cl_protname, clnt->cl_server);
 477         if (!IS_ERR(clnt->cl_path.dentry)) {
 478                 rpc_remove_client_dir(clnt->cl_path.dentry);
 479                 rpc_put_mount();
 480         }
 481         if (clnt->cl_parent != clnt) {
 482                 rpc_release_client(clnt->cl_parent);
 483                 goto out_free;
 484         }
 485         if (clnt->cl_server != clnt->cl_inline_name)
 486                 kfree(clnt->cl_server);
 487 out_free:
 488         rpc_unregister_client(clnt);
 489         rpc_free_iostats(clnt->cl_metrics);
 490         kfree(clnt->cl_principal);
 491         clnt->cl_metrics = NULL;
 492         xprt_put(clnt->cl_xprt);
 493         rpciod_down();
 494         kfree(clnt);
 495 }
 496
 497 /*
 498  * Free an RPC client
 499  */
 500 static void
 501 rpc_free_auth(struct rpc_clnt *clnt)
 502 {
 503         if (clnt->cl_auth == NULL) {
 504                 rpc_free_client(clnt);
 505                 return;
 506         }
 507
 508         /*
 509          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 510          *       release remaining GSS contexts. This mechanism ensures
 511          *       that it can do so safely.
 512          */
 513         atomic_inc(&clnt->cl_count);
 514         rpcauth_release(clnt->cl_auth);
 515         clnt->cl_auth = NULL;
 516         if (atomic_dec_and_test(&clnt->cl_count))
 517                 rpc_free_client(clnt);
 518 }
 519
 520 /*
 521  * Release reference to the RPC client
 522  */
 523 void
 524 rpc_release_client(struct rpc_clnt *clnt)
 525 {
 526         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 527
 528         if (list_empty(&clnt->cl_tasks))
 529                 wake_up(&destroy_wait);
 530         if (atomic_dec_and_test(&clnt->cl_count))
 531                 rpc_free_auth(clnt);
 532 }
 533
 534 /**
 535  * rpc_bind_new_program - bind a new RPC program to an existing client
 536  * @old: old rpc_client
 537  * @program: rpc program to set
 538  * @vers: rpc program version
 539  *
 540  * Clones the rpc client and sets up a new RPC program. This is mainly
 541  * of use for enabling different RPC programs to share the same transport.
 542  * The Sun NFSv2/v3 ACL protocol can do this.
 543  */
 544 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 545                                       struct rpc_program *program,
 546                                       u32 vers)
 547 {
 548         struct rpc_clnt *clnt;
 549         struct rpc_version *version;
 550         int err;
 551
 552         BUG_ON(vers >= program->nrvers || !program->version[vers]);
 553         version = program->version[vers];
 554         clnt = rpc_clone_client(old);
 555         if (IS_ERR(clnt))
 556                 goto out;
 557         clnt->cl_procinfo = version->procs;
 558         clnt->cl_maxproc  = version->nrprocs;
 559         clnt->cl_protname = program->name;
 560         clnt->cl_prog     = program->number;
 561         clnt->cl_vers     = version->number;
 562         clnt->cl_stats    = program->stats;
 563         err = rpc_ping(clnt);
 564         if (err != 0) {
 565                 rpc_shutdown_client(clnt);
 566                 clnt = ERR_PTR(err);
 567         }
 568 out:
 569         return clnt;
 570 }
 571 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 572
 573 void rpc_task_release_client(struct rpc_task *task)
 574 {
 575         struct rpc_clnt *clnt = task->tk_client;
 576
 577         if (clnt != NULL) {
 578                 /* Remove from client task list */
 579                 spin_lock(&clnt->cl_lock);
 580                 list_del(&task->tk_task);
 581                 spin_unlock(&clnt->cl_lock);
 582                 task->tk_client = NULL;
 583
 584                 rpc_release_client(clnt);
 585         }
 586 }
 587
 588 static
 589 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
 590 {
 591         if (clnt != NULL) {
 592                 rpc_task_release_client(task);
 593                 task->tk_client = clnt;
 594                 atomic_inc(&clnt->cl_count);
 595                 if (clnt->cl_softrtry)
 596                         task->tk_flags |= RPC_TASK_SOFT;
 597                 /* Add to the client's list of all tasks */
 598                 spin_lock(&clnt->cl_lock);
 599                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
 600                 spin_unlock(&clnt->cl_lock);
 601         }
 602 }
 603
 604 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
 605 {
 606         rpc_task_release_client(task);
 607         rpc_task_set_client(task, clnt);
 608 }
 609 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
 610
 611
 612 static void
 613 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
 614 {
 615         if (msg != NULL) {
 616                 task->tk_msg.rpc_proc = msg->rpc_proc;
 617                 task->tk_msg.rpc_argp = msg->rpc_argp;
 618                 task->tk_msg.rpc_resp = msg->rpc_resp;
 619                 if (msg->rpc_cred != NULL)
 620                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
 621         }
 622 }
 623
 624 /*
 625  * Default callback for async RPC calls
 626  */
 627 static void
 628 rpc_default_callback(struct rpc_task *task, void *data)
 629 {
 630 }
 631
 632 static const struct rpc_call_ops rpc_default_ops = {
 633         .rpc_call_done = rpc_default_callback,
 634 };
 635
 636 /**
 637  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 638  * @task_setup_data: pointer to task initialisation data
 639  */
 640 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 641 {
 642         struct rpc_task *task;
 643
 644         task = rpc_new_task(task_setup_data);
 645         if (IS_ERR(task))
 646                 goto out;
 647
 648         rpc_task_set_client(task, task_setup_data->rpc_client);
 649         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
 650
 651         if (task->tk_action == NULL)
 652                 rpc_call_start(task);
 653
 654         atomic_inc(&task->tk_count);
 655         rpc_execute(task);
 656 out:
 657         return task;
 658 }
 659 EXPORT_SYMBOL_GPL(rpc_run_task);
 660
 661 /**
 662  * rpc_call_sync - Perform a synchronous RPC call
 663  * @clnt: pointer to RPC client
 664  * @msg: RPC call parameters
 665  * @flags: RPC call flags
 666  */
 667 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 668 {
 669         struct rpc_task *task;
 670         struct rpc_task_setup task_setup_data = {
 671                 .rpc_client = clnt,
 672                 .rpc_message = msg,
 673                 .callback_ops = &rpc_default_ops,
 674                 .flags = flags,
 675         };
 676         int status;
 677
 678         BUG_ON(flags & RPC_TASK_ASYNC);
 679
 680         task = rpc_run_task(&task_setup_data);
 681         if (IS_ERR(task))
 682                 return PTR_ERR(task);
 683         status = task->tk_status;
 684         rpc_put_task(task);
 685         return status;
 686 }
 687 EXPORT_SYMBOL_GPL(rpc_call_sync);
 688
 689 /**
 690  * rpc_call_async - Perform an asynchronous RPC call
 691  * @clnt: pointer to RPC client
 692  * @msg: RPC call parameters
 693  * @flags: RPC call flags
 694  * @tk_ops: RPC call ops
 695  * @data: user call data
 696  */
 697 int
 698 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
 699                const struct rpc_call_ops *tk_ops, void *data)
 700 {
 701         struct rpc_task *task;
 702         struct rpc_task_setup task_setup_data = {
 703                 .rpc_client = clnt,
 704                 .rpc_message = msg,
 705                 .callback_ops = tk_ops,
 706                 .callback_data = data,
 707                 .flags = flags|RPC_TASK_ASYNC,
 708         };
 709
 710         task = rpc_run_task(&task_setup_data);
 711         if (IS_ERR(task))
 712                 return PTR_ERR(task);
 713         rpc_put_task(task);
 714         return 0;
 715 }
 716 EXPORT_SYMBOL_GPL(rpc_call_async);
 717
 718 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 719 /**
 720  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
 721  * rpc_execute against it
 722  * @req: RPC request
 723  * @tk_ops: RPC call ops
 724  */
 725 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
 726                                 const struct rpc_call_ops *tk_ops)
 727 {
 728         struct rpc_task *task;
 729         struct xdr_buf *xbufp = &req->rq_snd_buf;
 730         struct rpc_task_setup task_setup_data = {
 731                 .callback_ops = tk_ops,
 732         };
 733
 734         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
 735         /*
 736          * Create an rpc_task to send the data
 737          */
 738         task = rpc_new_task(&task_setup_data);
 739         if (IS_ERR(task)) {
 740                 xprt_free_bc_request(req);
 741                 goto out;
 742         }
 743         task->tk_rqstp = req;
 744
 745         /*
 746          * Set up the xdr_buf length.
 747          * This also indicates that the buffer is XDR encoded already.
 748          */
 749         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
 750                         xbufp->tail[0].iov_len;
 751
 752         task->tk_action = call_bc_transmit;
 753         atomic_inc(&task->tk_count);
 754         BUG_ON(atomic_read(&task->tk_count) != 2);
 755         rpc_execute(task);
 756
 757 out:
 758         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
 759         return task;
 760 }
 761 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
 762
 763 void
 764 rpc_call_start(struct rpc_task *task)
 765 {
 766         task->tk_action = call_start;
 767 }
 768 EXPORT_SYMBOL_GPL(rpc_call_start);
 769
 770 /**
 771  * rpc_peeraddr - extract remote peer address from clnt's xprt
 772  * @clnt: RPC client structure
 773  * @buf: target buffer
 774  * @bufsize: length of target buffer
 775  *
 776  * Returns the number of bytes that are actually in the stored address.
 777  */
 778 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
 779 {
 780         size_t bytes;
 781         struct rpc_xprt *xprt = clnt->cl_xprt;
 782
 783         bytes = sizeof(xprt->addr);
 784         if (bytes > bufsize)
 785                 bytes = bufsize;
 786         memcpy(buf, &clnt->cl_xprt->addr, bytes);
 787         return xprt->addrlen;
 788 }
 789 EXPORT_SYMBOL_GPL(rpc_peeraddr);
 790
 791 /**
 792  * rpc_peeraddr2str - return remote peer address in printable format
 793  * @clnt: RPC client structure
 794  * @format: address format
 795  *
 796  */
 797 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
 798                              enum rpc_display_format_t format)
 799 {
 800         struct rpc_xprt *xprt = clnt->cl_xprt;
 801
 802         if (xprt->address_strings[format] != NULL)
 803                 return xprt->address_strings[format];
 804         else
 805                 return "unprintable";
 806 }
 807 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
 808
 809 void
 810 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
 811 {
 812         struct rpc_xprt *xprt = clnt->cl_xprt;
 813         if (xprt->ops->set_buffer_size)
 814                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
 815 }
 816 EXPORT_SYMBOL_GPL(rpc_setbufsize);
 817
 818 /*
 819  * Return size of largest payload RPC client can support, in bytes
 820  *
 821  * For stream transports, this is one RPC record fragment (see RFC
 822  * 1831), as we don't support multi-record requests yet.  For datagram
 823  * transports, this is the size of an IP packet minus the IP, UDP, and
 824  * RPC header sizes.
 825  */
 826 size_t rpc_max_payload(struct rpc_clnt *clnt)
 827 {
 828         return clnt->cl_xprt->max_payload;
 829 }
 830 EXPORT_SYMBOL_GPL(rpc_max_payload);
 831
 832 /**
 833  * rpc_force_rebind - force transport to check that remote port is unchanged
 834  * @clnt: client to rebind
 835  *
 836  */
 837 void rpc_force_rebind(struct rpc_clnt *clnt)
 838 {
 839         if (clnt->cl_autobind)
 840                 xprt_clear_bound(clnt->cl_xprt);
 841 }
 842 EXPORT_SYMBOL_GPL(rpc_force_rebind);
 843
 844 /*
 845  * Restart an (async) RPC call from the call_prepare state.
 846  * Usually called from within the exit handler.
 847  */
 848 int
 849 rpc_restart_call_prepare(struct rpc_task *task)
 850 {
 851         if (RPC_ASSASSINATED(task))
 852                 return 0;
 853         task->tk_action = rpc_prepare_task;
 854         return 1;
 855 }
 856 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
 857
 858 /*
 859  * Restart an (async) RPC call. Usually called from within the
 860  * exit handler.
 861  */
 862 int
 863 rpc_restart_call(struct rpc_task *task)
 864 {
 865         if (RPC_ASSASSINATED(task))
 866                 return 0;
 867         task->tk_action = call_start;
 868         return 1;
 869 }
 870 EXPORT_SYMBOL_GPL(rpc_restart_call);
 871
 872 #ifdef RPC_DEBUG
 873 static const char *rpc_proc_name(const struct rpc_task *task)
 874 {
 875         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
 876
 877         if (proc) {
 878                 if (proc->p_name)
 879                         return proc->p_name;
 880                 else
 881                         return "NULL";
 882         } else
 883                 return "no proc";
 884 }
 885 #endif
 886
 887 /*
 888  * 0.  Initial state
 889  *
 890  *     Other FSM states can be visited zero or more times, but
 891  *     this state is visited exactly once for each RPC.
 892  */
 893 static void
 894 call_start(struct rpc_task *task)
 895 {
 896         struct rpc_clnt *clnt = task->tk_client;
 897
 898         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
 899                         clnt->cl_protname, clnt->cl_vers,
 900                         rpc_proc_name(task),
 901                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
 902
 903         /* Increment call count */
 904         task->tk_msg.rpc_proc->p_count++;
 905         clnt->cl_stats->rpccnt++;
 906         task->tk_action = call_reserve;
 907 }
 908
 909 /*
 910  * 1.   Reserve an RPC call slot
 911  */
 912 static void
 913 call_reserve(struct rpc_task *task)
 914 {
 915         dprint_status(task);
 916
 917         task->tk_status  = 0;
 918         task->tk_action  = call_reserveresult;
 919         xprt_reserve(task);
 920 }
 921
 922 /*
 923  * 1b.  Grok the result of xprt_reserve()
 924  */
 925 static void
 926 call_reserveresult(struct rpc_task *task)
 927 {
 928         int status = task->tk_status;
 929
 930         dprint_status(task);
 931
 932         /*
 933          * After a call to xprt_reserve(), we must have either
 934          * a request slot or else an error status.
 935          */
 936         task->tk_status = 0;
 937         if (status >= 0) {
 938                 if (task->tk_rqstp) {
 939                         task->tk_action = call_refresh;
 940                         return;
 941                 }
 942
 943                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
 944                                 __func__, status);
 945                 rpc_exit(task, -EIO);
 946                 return;
 947         }
 948
 949         /*
 950          * Even though there was an error, we may have acquired
 951          * a request slot somehow.  Make sure not to leak it.
 952          */
 953         if (task->tk_rqstp) {
 954                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
 955                                 __func__, status);
 956                 xprt_release(task);
 957         }
 958
 959         switch (status) {
 960         case -EAGAIN:   /* woken up; retry */
 961                 task->tk_action = call_reserve;
 962                 return;
 963         case -EIO:      /* probably a shutdown */
 964                 break;
 965         default:
 966                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
 967                                 __func__, status);
 968                 break;
 969         }
 970         rpc_exit(task, status);
 971 }
 972
 973 /*
 974  * 2.   Bind and/or refresh the credentials
 975  */
 976 static void
 977 call_refresh(struct rpc_task *task)
 978 {
 979         dprint_status(task);
 980
 981         task->tk_action = call_refreshresult;
 982         task->tk_status = 0;
 983         task->tk_client->cl_stats->rpcauthrefresh++;
 984         rpcauth_refreshcred(task);
 985 }
 986
 987 /*
 988  * 2a.  Process the results of a credential refresh
 989  */
 990 static void
 991 call_refreshresult(struct rpc_task *task)
 992 {
 993         int status = task->tk_status;
 994
 995         dprint_status(task);
 996
 997         task->tk_status = 0;
 998         task->tk_action = call_refresh;
 999         switch (status) {
1000         case 0:
1001                 if (rpcauth_uptodatecred(task))
1002                         task->tk_action = call_allocate;
1003                 return;
1004         case -ETIMEDOUT:
1005                 rpc_delay(task, 3*HZ);
1006         case -EAGAIN:
1007                 status = -EACCES;
1008                 if (!task->tk_cred_retry)
1009                         break;
1010                 task->tk_cred_retry--;
1011                 dprintk("RPC: %5u %s: retry refresh creds\n",
1012                                 task->tk_pid, __func__);
1013                 return;
1014         }
1015         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1016                                 task->tk_pid, __func__, status);
1017         rpc_exit(task, status);
1018 }
1019
1020 /*
1021  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1022  *      (Note: buffer memory is freed in xprt_release).
1023  */
1024 static void
1025 call_allocate(struct rpc_task *task)
1026 {
1027         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1028         struct rpc_rqst *req = task->tk_rqstp;
1029         struct rpc_xprt *xprt = task->tk_xprt;
1030         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1031
1032         dprint_status(task);
1033
1034         task->tk_status = 0;
1035         task->tk_action = call_bind;
1036
1037         if (req->rq_buffer)
1038                 return;
1039
1040         if (proc->p_proc != 0) {
1041                 BUG_ON(proc->p_arglen == 0);
1042                 if (proc->p_decode != NULL)
1043                         BUG_ON(proc->p_replen == 0);
1044         }
1045
1046         /*
1047          * Calculate the size (in quads) of the RPC call
1048          * and reply headers, and convert both values
1049          * to byte sizes.
1050          */
1051         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1052         req->rq_callsize <<= 2;
1053         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1054         req->rq_rcvsize <<= 2;
1055
1056         req->rq_buffer = xprt->ops->buf_alloc(task,
1057                                         req->rq_callsize + req->rq_rcvsize);
1058         if (req->rq_buffer != NULL)
1059                 return;
1060
1061         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1062
1063         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1064                 task->tk_action = call_allocate;
1065                 rpc_delay(task, HZ>>4);
1066                 return;
1067         }
1068
1069         rpc_exit(task, -ERESTARTSYS);
1070 }
1071
1072 static inline int
1073 rpc_task_need_encode(struct rpc_task *task)
1074 {
1075         return task->tk_rqstp->rq_snd_buf.len == 0;
1076 }
1077
1078 static inline void
1079 rpc_task_force_reencode(struct rpc_task *task)
1080 {
1081         task->tk_rqstp->rq_snd_buf.len = 0;
1082         task->tk_rqstp->rq_bytes_sent = 0;
1083 }
1084
1085 static inline void
1086 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1087 {
1088         buf->head[0].iov_base = start;
1089         buf->head[0].iov_len = len;
1090         buf->tail[0].iov_len = 0;
1091         buf->page_len = 0;
1092         buf->flags = 0;
1093         buf->len = 0;
1094         buf->buflen = len;
1095 }
1096
1097 /*
1098  * 3.   Encode arguments of an RPC call
1099  */
1100 static void
1101 rpc_xdr_encode(struct rpc_task *task)
1102 {
1103         struct rpc_rqst *req = task->tk_rqstp;
1104         kxdreproc_t     encode;
1105         __be32          *p;
1106
1107         dprint_status(task);
1108
1109         rpc_xdr_buf_init(&req->rq_snd_buf,
1110                          req->rq_buffer,
1111                          req->rq_callsize);
1112         rpc_xdr_buf_init(&req->rq_rcv_buf,
1113                          (char *)req->rq_buffer + req->rq_callsize,
1114                          req->rq_rcvsize);
1115
1116         p = rpc_encode_header(task);
1117         if (p == NULL) {
1118                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1119                 rpc_exit(task, -EIO);
1120                 return;
1121         }
1122
1123         encode = task->tk_msg.rpc_proc->p_encode;
1124         if (encode == NULL)
1125                 return;
1126
1127         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1128                         task->tk_msg.rpc_argp);
1129 }
1130
1131 /*
1132  * 4.   Get the server port number if not yet set
1133  */
1134 static void
1135 call_bind(struct rpc_task *task)
1136 {
1137         struct rpc_xprt *xprt = task->tk_xprt;
1138
1139         dprint_status(task);
1140
1141         task->tk_action = call_connect;
1142         if (!xprt_bound(xprt)) {
1143                 task->tk_action = call_bind_status;
1144                 task->tk_timeout = xprt->bind_timeout;
1145                 xprt->ops->rpcbind(task);
1146         }
1147 }
1148
1149 /*
1150  * 4a.  Sort out bind result
1151  */
1152 static void
1153 call_bind_status(struct rpc_task *task)
1154 {
1155         int status = -EIO;
1156
1157         if (task->tk_status >= 0) {
1158                 dprint_status(task);
1159                 task->tk_status = 0;
1160                 task->tk_action = call_connect;
1161                 return;
1162         }
1163
1164         switch (task->tk_status) {
1165         case -ENOMEM:
1166                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1167                 rpc_delay(task, HZ >> 2);
1168                 goto retry_timeout;
1169         case -EACCES:
1170                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1171                                 "unavailable\n", task->tk_pid);
1172                 /* fail immediately if this is an RPC ping */
1173                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1174                         status = -EOPNOTSUPP;
1175                         break;
1176                 }
1177                 if (task->tk_rebind_retry == 0)
1178                         break;
1179                 task->tk_rebind_retry--;
1180                 rpc_delay(task, 3*HZ);
1181                 goto retry_timeout;
1182         case -ETIMEDOUT:
1183                 dprintk("RPC: %5u rpcbind request timed out\n",
1184                                 task->tk_pid);
1185                 goto retry_timeout;
1186         case -EPFNOSUPPORT:
1187                 /* server doesn't support any rpcbind version we know of */
1188                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1189                                 task->tk_pid);
1190                 break;
1191         case -EPROTONOSUPPORT:
1192                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1193                                 task->tk_pid);
1194                 task->tk_status = 0;
1195                 task->tk_action = call_bind;
1196                 return;
1197         case -ECONNREFUSED:             /* connection problems */
1198         case -ECONNRESET:
1199         case -ENOTCONN:
1200         case -EHOSTDOWN:
1201         case -EHOSTUNREACH:
1202         case -ENETUNREACH:
1203         case -EPIPE:
1204                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1205                                 task->tk_pid, task->tk_status);
1206                 if (!RPC_IS_SOFTCONN(task)) {
1207                         rpc_delay(task, 5*HZ);
1208                         goto retry_timeout;
1209                 }
1210                 status = task->tk_status;
1211                 break;
1212         default:
1213                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1214                                 task->tk_pid, -task->tk_status);
1215         }
1216
1217         rpc_exit(task, status);
1218         return;
1219
1220 retry_timeout:
1221         task->tk_action = call_timeout;
1222 }
1223
1224 /*
1225  * 4b.  Connect to the RPC server
1226  */
1227 static void
1228 call_connect(struct rpc_task *task)
1229 {
1230         struct rpc_xprt *xprt = task->tk_xprt;
1231
1232         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1233                         task->tk_pid, xprt,
1234                         (xprt_connected(xprt) ? "is" : "is not"));
1235
1236         task->tk_action = call_transmit;
1237         if (!xprt_connected(xprt)) {
1238                 task->tk_action = call_connect_status;
1239                 if (task->tk_status < 0)
1240                         return;
1241                 xprt_connect(task);
1242         }
1243 }
1244
1245 /*
1246  * 4c.  Sort out connect result
1247  */
1248 static void
1249 call_connect_status(struct rpc_task *task)
1250 {
1251         struct rpc_clnt *clnt = task->tk_client;
1252         int status = task->tk_status;
1253
1254         dprint_status(task);
1255
1256         task->tk_status = 0;
1257         if (status >= 0 || status == -EAGAIN) {
1258                 clnt->cl_stats->netreconn++;
1259                 task->tk_action = call_transmit;
1260                 return;
1261         }
1262
1263         switch (status) {
1264                 /* if soft mounted, test if we've timed out */
1265         case -ETIMEDOUT:
1266                 task->tk_action = call_timeout;
1267                 break;
1268         default:
1269                 rpc_exit(task, -EIO);
1270         }
1271 }
1272
1273 /*
1274  * 5.   Transmit the RPC request, and wait for reply
1275  */
1276 static void
1277 call_transmit(struct rpc_task *task)
1278 {
1279         dprint_status(task);
1280
1281         task->tk_action = call_status;
1282         if (task->tk_status < 0)
1283                 return;
1284         task->tk_status = xprt_prepare_transmit(task);
1285         if (task->tk_status != 0)
1286                 return;
1287         task->tk_action = call_transmit_status;
1288         /* Encode here so that rpcsec_gss can use correct sequence number. */
1289         if (rpc_task_need_encode(task)) {
1290                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1291                 rpc_xdr_encode(task);
1292                 /* Did the encode result in an error condition? */
1293                 if (task->tk_status != 0) {
1294                         /* Was the error nonfatal? */
1295                         if (task->tk_status == -EAGAIN)
1296                                 rpc_delay(task, HZ >> 4);
1297                         else
1298                                 rpc_exit(task, task->tk_status);
1299                         return;
1300                 }
1301         }
1302         xprt_transmit(task);
1303         if (task->tk_status < 0)
1304                 return;
1305         /*
1306          * On success, ensure that we call xprt_end_transmit() before sleeping
1307          * in order to allow access to the socket to other RPC requests.
1308          */
1309         call_transmit_status(task);
1310         if (rpc_reply_expected(task))
1311                 return;
1312         task->tk_action = rpc_exit_task;
1313         rpc_wake_up_queued_task(&task->tk_xprt->pending, task);
1314 }
1315
1316 /*
1317  * 5a.  Handle cleanup after a transmission
1318  */
1319 static void
1320 call_transmit_status(struct rpc_task *task)
1321 {
1322         task->tk_action = call_status;
1323
1324         /*
1325          * Common case: success.  Force the compiler to put this
1326          * test first.
1327          */
1328         if (task->tk_status == 0) {
1329                 xprt_end_transmit(task);
1330                 rpc_task_force_reencode(task);
1331                 return;
1332         }
1333
1334         switch (task->tk_status) {
1335         case -EAGAIN:
1336                 break;
1337         default:
1338                 dprint_status(task);
1339                 xprt_end_transmit(task);
1340                 rpc_task_force_reencode(task);
1341                 break;
1342                 /*
1343                  * Special cases: if we've been waiting on the
1344                  * socket's write_space() callback, or if the
1345                  * socket just returned a connection error,
1346                  * then hold onto the transport lock.
1347                  */
1348         case -ECONNREFUSED:
1349         case -EHOSTDOWN:
1350         case -EHOSTUNREACH:
1351         case -ENETUNREACH:
1352                 if (RPC_IS_SOFTCONN(task)) {
1353                         xprt_end_transmit(task);
1354                         rpc_exit(task, task->tk_status);
1355                         break;
1356                 }
1357         case -ECONNRESET:
1358         case -ENOTCONN:
1359         case -EPIPE:
1360                 rpc_task_force_reencode(task);
1361         }
1362 }
1363
1364 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1365 /*
1366  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1367  * addition, disconnect on connectivity errors.
1368  */
1369 static void
1370 call_bc_transmit(struct rpc_task *task)
1371 {
1372         struct rpc_rqst *req = task->tk_rqstp;
1373
1374         BUG_ON(task->tk_status != 0);
1375         task->tk_status = xprt_prepare_transmit(task);
1376         if (task->tk_status == -EAGAIN) {
1377                 /*
1378                  * Could not reserve the transport. Try again after the
1379                  * transport is released.
1380                  */
1381                 task->tk_status = 0;
1382                 task->tk_action = call_bc_transmit;
1383                 return;
1384         }
1385
1386         task->tk_action = rpc_exit_task;
1387         if (task->tk_status < 0) {
1388                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1389                         "error: %d\n", task->tk_status);
1390                 return;
1391         }
1392
1393         xprt_transmit(task);
1394         xprt_end_transmit(task);
1395         dprint_status(task);
1396         switch (task->tk_status) {
1397         case 0:
1398                 /* Success */
1399                 break;
1400         case -EHOSTDOWN:
1401         case -EHOSTUNREACH:
1402         case -ENETUNREACH:
1403         case -ETIMEDOUT:
1404                 /*
1405                  * Problem reaching the server.  Disconnect and let the
1406                  * forechannel reestablish the connection.  The server will
1407                  * have to retransmit the backchannel request and we'll
1408                  * reprocess it.  Since these ops are idempotent, there's no
1409                  * need to cache our reply at this time.
1410                  */
1411                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1412                         "error: %d\n", task->tk_status);
1413                 xprt_conditional_disconnect(task->tk_xprt,
1414                         req->rq_connect_cookie);
1415                 break;
1416         default:
1417                 /*
1418                  * We were unable to reply and will have to drop the
1419                  * request.  The server should reconnect and retransmit.
1420                  */
1421                 BUG_ON(task->tk_status == -EAGAIN);
1422                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1423                         "error: %d\n", task->tk_status);
1424                 break;
1425         }
1426         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1427 }
1428 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1429
1430 /*
1431  * 6.   Sort out the RPC call status
1432  */
1433 static void
1434 call_status(struct rpc_task *task)
1435 {
1436         struct rpc_clnt *clnt = task->tk_client;
1437         struct rpc_rqst *req = task->tk_rqstp;
1438         int             status;
1439
1440         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
1441                 task->tk_status = req->rq_reply_bytes_recvd;
1442
1443         dprint_status(task);
1444
1445         status = task->tk_status;
1446         if (status >= 0) {
1447                 task->tk_action = call_decode;
1448                 return;
1449         }
1450
1451         task->tk_status = 0;
1452         switch(status) {
1453         case -EHOSTDOWN:
1454         case -EHOSTUNREACH:
1455         case -ENETUNREACH:
1456                 /*
1457                  * Delay any retries for 3 seconds, then handle as if it
1458                  * were a timeout.
1459                  */
1460                 rpc_delay(task, 3*HZ);
1461         case -ETIMEDOUT:
1462                 task->tk_action = call_timeout;
1463                 if (task->tk_client->cl_discrtry)
1464                         xprt_conditional_disconnect(task->tk_xprt,
1465                                         req->rq_connect_cookie);
1466                 break;
1467         case -ECONNRESET:
1468         case -ECONNREFUSED:
1469                 rpc_force_rebind(clnt);
1470                 rpc_delay(task, 3*HZ);
1471         case -EPIPE:
1472         case -ENOTCONN:
1473                 task->tk_action = call_bind;
1474                 break;
1475         case -EAGAIN:
1476                 task->tk_action = call_transmit;
1477                 break;
1478         case -EIO:
1479                 /* shutdown or soft timeout */
1480                 rpc_exit(task, status);
1481                 break;
1482         default:
1483                 if (clnt->cl_chatty)
1484                         printk("%s: RPC call returned error %d\n",
1485                                clnt->cl_protname, -status);
1486                 rpc_exit(task, status);
1487         }
1488 }
1489
1490 /*
1491  * 6a.  Handle RPC timeout
1492  *      We do not release the request slot, so we keep using the
1493  *      same XID for all retransmits.
1494  */
1495 static void
1496 call_timeout(struct rpc_task *task)
1497 {
1498         struct rpc_clnt *clnt = task->tk_client;
1499
1500         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1501                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1502                 goto retry;
1503         }
1504
1505         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1506         task->tk_timeouts++;
1507
1508         if (RPC_IS_SOFTCONN(task)) {
1509                 rpc_exit(task, -ETIMEDOUT);
1510                 return;
1511         }
1512         if (RPC_IS_SOFT(task)) {
1513                 if (clnt->cl_chatty)
1514                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1515                                 clnt->cl_protname, clnt->cl_server);
1516                 if (task->tk_flags & RPC_TASK_TIMEOUT)
1517                         rpc_exit(task, -ETIMEDOUT);
1518                 else
1519                         rpc_exit(task, -EIO);
1520                 return;
1521         }
1522
1523         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1524                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1525                 if (clnt->cl_chatty)
1526                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1527                         clnt->cl_protname, clnt->cl_server);
1528         }
1529         rpc_force_rebind(clnt);
1530         /*
1531          * Did our request time out due to an RPCSEC_GSS out-of-sequence
1532          * event? RFC2203 requires the server to drop all such requests.
1533          */
1534         rpcauth_invalcred(task);
1535
1536 retry:
1537         clnt->cl_stats->rpcretrans++;
1538         task->tk_action = call_bind;
1539         task->tk_status = 0;
1540 }
1541
1542 /*
1543  * 7.   Decode the RPC reply
1544  */
1545 static void
1546 call_decode(struct rpc_task *task)
1547 {
1548         struct rpc_clnt *clnt = task->tk_client;
1549         struct rpc_rqst *req = task->tk_rqstp;
1550         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
1551         __be32          *p;
1552
1553         dprint_status(task);
1554
1555         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1556                 if (clnt->cl_chatty)
1557                         printk(KERN_NOTICE "%s: server %s OK\n",
1558                                 clnt->cl_protname, clnt->cl_server);
1559                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1560         }
1561
1562         /*
1563          * Ensure that we see all writes made by xprt_complete_rqst()
1564          * before it changed req->rq_reply_bytes_recvd.
1565          */
1566         smp_rmb();
1567         req->rq_rcv_buf.len = req->rq_private_buf.len;
1568
1569         /* Check that the softirq receive buffer is valid */
1570         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1571                                 sizeof(req->rq_rcv_buf)) != 0);
1572
1573         if (req->rq_rcv_buf.len < 12) {
1574                 if (!RPC_IS_SOFT(task)) {
1575                         task->tk_action = call_bind;
1576                         clnt->cl_stats->rpcretrans++;
1577                         goto out_retry;
1578                 }
1579                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1580                                 clnt->cl_protname, task->tk_status);
1581                 task->tk_action = call_timeout;
1582                 goto out_retry;
1583         }
1584
1585         p = rpc_verify_header(task);
1586         if (IS_ERR(p)) {
1587                 if (p == ERR_PTR(-EAGAIN))
1588                         goto out_retry;
1589                 return;
1590         }
1591
1592         task->tk_action = rpc_exit_task;
1593
1594         if (decode) {
1595                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1596                                                       task->tk_msg.rpc_resp);
1597         }
1598         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1599                         task->tk_status);
1600         return;
1601 out_retry:
1602         task->tk_status = 0;
1603         /* Note: rpc_verify_header() may have freed the RPC slot */
1604         if (task->tk_rqstp == req) {
1605                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
1606                 if (task->tk_client->cl_discrtry)
1607                         xprt_conditional_disconnect(task->tk_xprt,
1608                                         req->rq_connect_cookie);
1609         }
1610 }
1611
1612 static __be32 *
1613 rpc_encode_header(struct rpc_task *task)
1614 {
1615         struct rpc_clnt *clnt = task->tk_client;
1616         struct rpc_rqst *req = task->tk_rqstp;
1617         __be32          *p = req->rq_svec[0].iov_base;
1618
1619         /* FIXME: check buffer size? */
1620
1621         p = xprt_skip_transport_header(task->tk_xprt, p);
1622         *p++ = req->rq_xid;             /* XID */
1623         *p++ = htonl(RPC_CALL);         /* CALL */
1624         *p++ = htonl(RPC_VERSION);      /* RPC version */
1625         *p++ = htonl(clnt->cl_prog);    /* program number */
1626         *p++ = htonl(clnt->cl_vers);    /* program version */
1627         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1628         p = rpcauth_marshcred(task, p);
1629         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1630         return p;
1631 }
1632
1633 static __be32 *
1634 rpc_verify_header(struct rpc_task *task)
1635 {
1636         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1637         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1638         __be32  *p = iov->iov_base;
1639         u32 n;
1640         int error = -EACCES;
1641
1642         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1643                 /* RFC-1014 says that the representation of XDR data must be a
1644                  * multiple of four bytes
1645                  * - if it isn't pointer subtraction in the NFS client may give
1646                  *   undefined results
1647                  */
1648                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
1649                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
1650                        task->tk_rqstp->rq_rcv_buf.len);
1651                 goto out_eio;
1652         }
1653         if ((len -= 3) < 0)
1654                 goto out_overflow;
1655
1656         p += 1; /* skip XID */
1657         if ((n = ntohl(*p++)) != RPC_REPLY) {
1658                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1659                         task->tk_pid, __func__, n);
1660                 goto out_garbage;
1661         }
1662
1663         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1664                 if (--len < 0)
1665                         goto out_overflow;
1666                 switch ((n = ntohl(*p++))) {
1667                 case RPC_AUTH_ERROR:
1668                         break;
1669                 case RPC_MISMATCH:
1670                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
1671                                 task->tk_pid, __func__);
1672                         error = -EPROTONOSUPPORT;
1673                         goto out_err;
1674                 default:
1675                         dprintk("RPC: %5u %s: RPC call rejected, "
1676                                 "unknown error: %x\n",
1677                                 task->tk_pid, __func__, n);
1678                         goto out_eio;
1679                 }
1680                 if (--len < 0)
1681                         goto out_overflow;
1682                 switch ((n = ntohl(*p++))) {
1683                 case RPC_AUTH_REJECTEDCRED:
1684                 case RPC_AUTH_REJECTEDVERF:
1685                 case RPCSEC_GSS_CREDPROBLEM:
1686                 case RPCSEC_GSS_CTXPROBLEM:
1687                         if (!task->tk_cred_retry)
1688                                 break;
1689                         task->tk_cred_retry--;
1690                         dprintk("RPC: %5u %s: retry stale creds\n",
1691                                         task->tk_pid, __func__);
1692                         rpcauth_invalcred(task);
1693                         /* Ensure we obtain a new XID! */
1694                         xprt_release(task);
1695                         task->tk_action = call_reserve;
1696                         goto out_retry;
1697                 case RPC_AUTH_BADCRED:
1698                 case RPC_AUTH_BADVERF:
1699                         /* possibly garbled cred/verf? */
1700                         if (!task->tk_garb_retry)
1701                                 break;
1702                         task->tk_garb_retry--;
1703                         dprintk("RPC: %5u %s: retry garbled creds\n",
1704                                         task->tk_pid, __func__);
1705                         task->tk_action = call_bind;
1706                         goto out_retry;
1707                 case RPC_AUTH_TOOWEAK:
1708                         printk(KERN_NOTICE "RPC: server %s requires stronger "
1709                                "authentication.\n", task->tk_client->cl_server);
1710                         break;
1711                 default:
1712                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
1713                                         task->tk_pid, __func__, n);
1714                         error = -EIO;
1715                 }
1716                 dprintk("RPC: %5u %s: call rejected %d\n",
1717                                 task->tk_pid, __func__, n);
1718                 goto out_err;
1719         }
1720         if (!(p = rpcauth_checkverf(task, p))) {
1721                 dprintk("RPC: %5u %s: auth check failed\n",
1722                                 task->tk_pid, __func__);
1723                 goto out_garbage;               /* bad verifier, retry */
1724         }
1725         len = p - (__be32 *)iov->iov_base - 1;
1726         if (len < 0)
1727                 goto out_overflow;
1728         switch ((n = ntohl(*p++))) {
1729         case RPC_SUCCESS:
1730                 return p;
1731         case RPC_PROG_UNAVAIL:
1732                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1733                                 task->tk_pid, __func__,
1734                                 (unsigned int)task->tk_client->cl_prog,
1735                                 task->tk_client->cl_server);
1736                 error = -EPFNOSUPPORT;
1737                 goto out_err;
1738         case RPC_PROG_MISMATCH:
1739                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1740                                 "server %s\n", task->tk_pid, __func__,
1741                                 (unsigned int)task->tk_client->cl_prog,
1742                                 (unsigned int)task->tk_client->cl_vers,
1743                                 task->tk_client->cl_server);
1744                 error = -EPROTONOSUPPORT;
1745                 goto out_err;
1746         case RPC_PROC_UNAVAIL:
1747                 dprintk("RPC: %5u %s: proc %s unsupported by program %u, "
1748                                 "version %u on server %s\n",
1749                                 task->tk_pid, __func__,
1750                                 rpc_proc_name(task),
1751                                 task->tk_client->cl_prog,
1752                                 task->tk_client->cl_vers,
1753                                 task->tk_client->cl_server);
1754                 error = -EOPNOTSUPP;
1755                 goto out_err;
1756         case RPC_GARBAGE_ARGS:
1757                 dprintk("RPC: %5u %s: server saw garbage\n",
1758                                 task->tk_pid, __func__);
1759                 break;                  /* retry */
1760         default:
1761                 dprintk("RPC: %5u %s: server accept status: %x\n",
1762                                 task->tk_pid, __func__, n);
1763                 /* Also retry */
1764         }
1765
1766 out_garbage:
1767         task->tk_client->cl_stats->rpcgarbage++;
1768         if (task->tk_garb_retry) {
1769                 task->tk_garb_retry--;
1770                 dprintk("RPC: %5u %s: retrying\n",
1771                                 task->tk_pid, __func__);
1772                 task->tk_action = call_bind;
1773 out_retry:
1774                 return ERR_PTR(-EAGAIN);
1775         }
1776 out_eio:
1777         error = -EIO;
1778 out_err:
1779         rpc_exit(task, error);
1780         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1781                         __func__, error);
1782         return ERR_PTR(error);
1783 out_overflow:
1784         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1785                         __func__);
1786         goto out_garbage;
1787 }
1788
1789 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
1790 {
1791 }
1792
1793 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
1794 {
1795         return 0;
1796 }
1797
1798 static struct rpc_procinfo rpcproc_null = {
1799         .p_encode = rpcproc_encode_null,
1800         .p_decode = rpcproc_decode_null,
1801 };
1802
1803 static int rpc_ping(struct rpc_clnt *clnt)
1804 {
1805         struct rpc_message msg = {
1806                 .rpc_proc = &rpcproc_null,
1807         };
1808         int err;
1809         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1810         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
1811         put_rpccred(msg.rpc_cred);
1812         return err;
1813 }
1814
1815 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1816 {
1817         struct rpc_message msg = {
1818                 .rpc_proc = &rpcproc_null,
1819                 .rpc_cred = cred,
1820         };
1821         struct rpc_task_setup task_setup_data = {
1822                 .rpc_client = clnt,
1823                 .rpc_message = &msg,
1824                 .callback_ops = &rpc_default_ops,
1825                 .flags = flags,
1826         };
1827         return rpc_run_task(&task_setup_data);
1828 }
1829 EXPORT_SYMBOL_GPL(rpc_call_null);
1830
1831 #ifdef RPC_DEBUG
1832 static void rpc_show_header(void)
1833 {
1834         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
1835                 "-timeout ---ops--\n");
1836 }
1837
1838 static void rpc_show_task(const struct rpc_clnt *clnt,
1839                           const struct rpc_task *task)
1840 {
1841         const char *rpc_waitq = "none";
1842
1843         if (RPC_IS_QUEUED(task))
1844                 rpc_waitq = rpc_qname(task->tk_waitqueue);
1845
1846         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
1847                 task->tk_pid, task->tk_flags, task->tk_status,
1848                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
1849                 clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
1850                 task->tk_action, rpc_waitq);
1851 }
1852
1853 void rpc_show_tasks(void)
1854 {
1855         struct rpc_clnt *clnt;
1856         struct rpc_task *task;
1857         int header = 0;
1858
1859         spin_lock(&rpc_client_lock);
1860         list_for_each_entry(clnt, &all_clients, cl_clients) {
1861                 spin_lock(&clnt->cl_lock);
1862                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
1863                         if (!header) {
1864                                 rpc_show_header();
1865                                 header++;
1866                         }
1867                         rpc_show_task(clnt, task);
1868                 }
1869                 spin_unlock(&clnt->cl_lock);
1870         }
1871         spin_unlock(&rpc_client_lock);
1872 }
1873 #endif