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
  21 #include <linux/module.h>
  22 #include <linux/types.h>
  23 #include <linux/kallsyms.h>
  24 #include <linux/mm.h>
  25 #include <linux/namei.h>
  26 #include <linux/mount.h>
  27 #include <linux/slab.h>
  28 #include <linux/rcupdate.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/addr.h>
  37 #include <linux/sunrpc/rpc_pipe_fs.h>
  38 #include <linux/sunrpc/metrics.h>
  39 #include <linux/sunrpc/bc_xprt.h>
  40 #include <trace/events/sunrpc.h>
  41
  42 #include "sunrpc.h"
  43 #include "netns.h"
  44
  45 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
  46 # define RPCDBG_FACILITY        RPCDBG_CALL
  47 #endif
  48
  49 #define dprint_status(t)                                        \
  50         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
  51                         __func__, t->tk_status)
  52
  53 /*
  54  * All RPC clients are linked into this list
  55  */
  56
  57 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
  58
  59
  60 static void     call_start(struct rpc_task *task);
  61 static void     call_reserve(struct rpc_task *task);
  62 static void     call_reserveresult(struct rpc_task *task);
  63 static void     call_allocate(struct rpc_task *task);
  64 static void     call_decode(struct rpc_task *task);
  65 static void     call_bind(struct rpc_task *task);
  66 static void     call_bind_status(struct rpc_task *task);
  67 static void     call_transmit(struct rpc_task *task);
  68 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
  69 static void     call_bc_transmit(struct rpc_task *task);
  70 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
  71 static void     call_status(struct rpc_task *task);
  72 static void     call_transmit_status(struct rpc_task *task);
  73 static void     call_refresh(struct rpc_task *task);
  74 static void     call_refreshresult(struct rpc_task *task);
  75 static void     call_timeout(struct rpc_task *task);
  76 static void     call_connect(struct rpc_task *task);
  77 static void     call_connect_status(struct rpc_task *task);
  78
  79 static __be32   *rpc_encode_header(struct rpc_task *task);
  80 static __be32   *rpc_verify_header(struct rpc_task *task);
  81 static int      rpc_ping(struct rpc_clnt *clnt);
  82
  83 static void rpc_register_client(struct rpc_clnt *clnt)
  84 {
  85         struct net *net = rpc_net_ns(clnt);
  86         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
  87
  88         spin_lock(&sn->rpc_client_lock);
  89         list_add(&clnt->cl_clients, &sn->all_clients);
  90         spin_unlock(&sn->rpc_client_lock);
  91 }
  92
  93 static void rpc_unregister_client(struct rpc_clnt *clnt)
  94 {
  95         struct net *net = rpc_net_ns(clnt);
  96         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
  97
  98         spin_lock(&sn->rpc_client_lock);
  99         list_del(&clnt->cl_clients);
 100         spin_unlock(&sn->rpc_client_lock);
 101 }
 102
 103 static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
 104 {
 105         rpc_remove_client_dir(clnt);
 106 }
 107
 108 static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
 109 {
 110         struct net *net = rpc_net_ns(clnt);
 111         struct super_block *pipefs_sb;
 112
 113         pipefs_sb = rpc_get_sb_net(net);
 114         if (pipefs_sb) {
 115                 __rpc_clnt_remove_pipedir(clnt);
 116                 rpc_put_sb_net(net);
 117         }
 118 }
 119
 120 static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
 121                                     struct rpc_clnt *clnt)
 122 {
 123         static uint32_t clntid;
 124         const char *dir_name = clnt->cl_program->pipe_dir_name;
 125         char name[15];
 126         struct dentry *dir, *dentry;
 127
 128         dir = rpc_d_lookup_sb(sb, dir_name);
 129         if (dir == NULL) {
 130                 pr_info("RPC: pipefs directory doesn't exist: %s\n", dir_name);
 131                 return dir;
 132         }
 133         for (;;) {
 134                 snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
 135                 name[sizeof(name) - 1] = '\0';
 136                 dentry = rpc_create_client_dir(dir, name, clnt);
 137                 if (!IS_ERR(dentry))
 138                         break;
 139                 if (dentry == ERR_PTR(-EEXIST))
 140                         continue;
 141                 printk(KERN_INFO "RPC: Couldn't create pipefs entry"
 142                                 " %s/%s, error %ld\n",
 143                                 dir_name, name, PTR_ERR(dentry));
 144                 break;
 145         }
 146         dput(dir);
 147         return dentry;
 148 }
 149
 150 static int
 151 rpc_setup_pipedir(struct super_block *pipefs_sb, struct rpc_clnt *clnt)
 152 {
 153         struct dentry *dentry;
 154
 155         if (clnt->cl_program->pipe_dir_name != NULL) {
 156                 dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt);
 157                 if (IS_ERR(dentry))
 158                         return PTR_ERR(dentry);
 159         }
 160         return 0;
 161 }
 162
 163 static int rpc_clnt_skip_event(struct rpc_clnt *clnt, unsigned long event)
 164 {
 165         if (clnt->cl_program->pipe_dir_name == NULL)
 166                 return 1;
 167
 168         switch (event) {
 169         case RPC_PIPEFS_MOUNT:
 170                 if (clnt->cl_pipedir_objects.pdh_dentry != NULL)
 171                         return 1;
 172                 if (atomic_read(&clnt->cl_count) == 0)
 173                         return 1;
 174                 break;
 175         case RPC_PIPEFS_UMOUNT:
 176                 if (clnt->cl_pipedir_objects.pdh_dentry == NULL)
 177                         return 1;
 178                 break;
 179         }
 180         return 0;
 181 }
 182
 183 static int __rpc_clnt_handle_event(struct rpc_clnt *clnt, unsigned long event,
 184                                    struct super_block *sb)
 185 {
 186         struct dentry *dentry;
 187         int err = 0;
 188
 189         switch (event) {
 190         case RPC_PIPEFS_MOUNT:
 191                 dentry = rpc_setup_pipedir_sb(sb, clnt);
 192                 if (!dentry)
 193                         return -ENOENT;
 194                 if (IS_ERR(dentry))
 195                         return PTR_ERR(dentry);
 196                 break;
 197         case RPC_PIPEFS_UMOUNT:
 198                 __rpc_clnt_remove_pipedir(clnt);
 199                 break;
 200         default:
 201                 printk(KERN_ERR "%s: unknown event: %ld\n", __func__, event);
 202                 return -ENOTSUPP;
 203         }
 204         return err;
 205 }
 206
 207 static int __rpc_pipefs_event(struct rpc_clnt *clnt, unsigned long event,
 208                                 struct super_block *sb)
 209 {
 210         int error = 0;
 211
 212         for (;; clnt = clnt->cl_parent) {
 213                 if (!rpc_clnt_skip_event(clnt, event))
 214                         error = __rpc_clnt_handle_event(clnt, event, sb);
 215                 if (error || clnt == clnt->cl_parent)
 216                         break;
 217         }
 218         return error;
 219 }
 220
 221 static struct rpc_clnt *rpc_get_client_for_event(struct net *net, int event)
 222 {
 223         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
 224         struct rpc_clnt *clnt;
 225
 226         spin_lock(&sn->rpc_client_lock);
 227         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
 228                 if (rpc_clnt_skip_event(clnt, event))
 229                         continue;
 230                 spin_unlock(&sn->rpc_client_lock);
 231                 return clnt;
 232         }
 233         spin_unlock(&sn->rpc_client_lock);
 234         return NULL;
 235 }
 236
 237 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
 238                             void *ptr)
 239 {
 240         struct super_block *sb = ptr;
 241         struct rpc_clnt *clnt;
 242         int error = 0;
 243
 244         while ((clnt = rpc_get_client_for_event(sb->s_fs_info, event))) {
 245                 error = __rpc_pipefs_event(clnt, event, sb);
 246                 if (error)
 247                         break;
 248         }
 249         return error;
 250 }
 251
 252 static struct notifier_block rpc_clients_block = {
 253         .notifier_call  = rpc_pipefs_event,
 254         .priority       = SUNRPC_PIPEFS_RPC_PRIO,
 255 };
 256
 257 int rpc_clients_notifier_register(void)
 258 {
 259         return rpc_pipefs_notifier_register(&rpc_clients_block);
 260 }
 261
 262 void rpc_clients_notifier_unregister(void)
 263 {
 264         return rpc_pipefs_notifier_unregister(&rpc_clients_block);
 265 }
 266
 267 static struct rpc_xprt *rpc_clnt_set_transport(struct rpc_clnt *clnt,
 268                 struct rpc_xprt *xprt,
 269                 const struct rpc_timeout *timeout)
 270 {
 271         struct rpc_xprt *old;
 272
 273         spin_lock(&clnt->cl_lock);
 274         old = rcu_dereference_protected(clnt->cl_xprt,
 275                         lockdep_is_held(&clnt->cl_lock));
 276
 277         if (!xprt_bound(xprt))
 278                 clnt->cl_autobind = 1;
 279
 280         clnt->cl_timeout = timeout;
 281         rcu_assign_pointer(clnt->cl_xprt, xprt);
 282         spin_unlock(&clnt->cl_lock);
 283
 284         return old;
 285 }
 286
 287 static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename)
 288 {
 289         clnt->cl_nodelen = strlcpy(clnt->cl_nodename,
 290                         nodename, sizeof(clnt->cl_nodename));
 291 }
 292
 293 static int rpc_client_register(struct rpc_clnt *clnt,
 294                                rpc_authflavor_t pseudoflavor,
 295                                const char *client_name)
 296 {
 297         struct rpc_auth_create_args auth_args = {
 298                 .pseudoflavor = pseudoflavor,
 299                 .target_name = client_name,
 300         };
 301         struct rpc_auth *auth;
 302         struct net *net = rpc_net_ns(clnt);
 303         struct super_block *pipefs_sb;
 304         int err;
 305
 306         rpc_clnt_debugfs_register(clnt);
 307
 308         pipefs_sb = rpc_get_sb_net(net);
 309         if (pipefs_sb) {
 310                 err = rpc_setup_pipedir(pipefs_sb, clnt);
 311                 if (err)
 312                         goto out;
 313         }
 314
 315         rpc_register_client(clnt);
 316         if (pipefs_sb)
 317                 rpc_put_sb_net(net);
 318
 319         auth = rpcauth_create(&auth_args, clnt);
 320         if (IS_ERR(auth)) {
 321                 dprintk("RPC:       Couldn't create auth handle (flavor %u)\n",
 322                                 pseudoflavor);
 323                 err = PTR_ERR(auth);
 324                 goto err_auth;
 325         }
 326         return 0;
 327 err_auth:
 328         pipefs_sb = rpc_get_sb_net(net);
 329         rpc_unregister_client(clnt);
 330         __rpc_clnt_remove_pipedir(clnt);
 331 out:
 332         if (pipefs_sb)
 333                 rpc_put_sb_net(net);
 334         rpc_clnt_debugfs_unregister(clnt);
 335         return err;
 336 }
 337
 338 static DEFINE_IDA(rpc_clids);
 339
 340 static int rpc_alloc_clid(struct rpc_clnt *clnt)
 341 {
 342         int clid;
 343
 344         clid = ida_simple_get(&rpc_clids, 0, 0, GFP_KERNEL);
 345         if (clid < 0)
 346                 return clid;
 347         clnt->cl_clid = clid;
 348         return 0;
 349 }
 350
 351 static void rpc_free_clid(struct rpc_clnt *clnt)
 352 {
 353         ida_simple_remove(&rpc_clids, clnt->cl_clid);
 354 }
 355
 356 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args,
 357                 struct rpc_xprt *xprt,
 358                 struct rpc_clnt *parent)
 359 {
 360         const struct rpc_program *program = args->program;
 361         const struct rpc_version *version;
 362         struct rpc_clnt *clnt = NULL;
 363         const struct rpc_timeout *timeout;
 364         const char *nodename = args->nodename;
 365         int err;
 366
 367         /* sanity check the name before trying to print it */
 368         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
 369                         program->name, args->servername, xprt);
 370
 371         err = rpciod_up();
 372         if (err)
 373                 goto out_no_rpciod;
 374
 375         err = -EINVAL;
 376         if (args->version >= program->nrvers)
 377                 goto out_err;
 378         version = program->version[args->version];
 379         if (version == NULL)
 380                 goto out_err;
 381
 382         err = -ENOMEM;
 383         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
 384         if (!clnt)
 385                 goto out_err;
 386         clnt->cl_parent = parent ? : clnt;
 387
 388         err = rpc_alloc_clid(clnt);
 389         if (err)
 390                 goto out_no_clid;
 391
 392         clnt->cl_procinfo = version->procs;
 393         clnt->cl_maxproc  = version->nrprocs;
 394         clnt->cl_prog     = args->prognumber ? : program->number;
 395         clnt->cl_vers     = version->number;
 396         clnt->cl_stats    = program->stats;
 397         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
 398         rpc_init_pipe_dir_head(&clnt->cl_pipedir_objects);
 399         err = -ENOMEM;
 400         if (clnt->cl_metrics == NULL)
 401                 goto out_no_stats;
 402         clnt->cl_program  = program;
 403         INIT_LIST_HEAD(&clnt->cl_tasks);
 404         spin_lock_init(&clnt->cl_lock);
 405
 406         timeout = xprt->timeout;
 407         if (args->timeout != NULL) {
 408                 memcpy(&clnt->cl_timeout_default, args->timeout,
 409                                 sizeof(clnt->cl_timeout_default));
 410                 timeout = &clnt->cl_timeout_default;
 411         }
 412
 413         rpc_clnt_set_transport(clnt, xprt, timeout);
 414
 415         clnt->cl_rtt = &clnt->cl_rtt_default;
 416         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
 417
 418         atomic_set(&clnt->cl_count, 1);
 419
 420         if (nodename == NULL)
 421                 nodename = utsname()->nodename;
 422         /* save the nodename */
 423         rpc_clnt_set_nodename(clnt, nodename);
 424
 425         err = rpc_client_register(clnt, args->authflavor, args->client_name);
 426         if (err)
 427                 goto out_no_path;
 428         if (parent)
 429                 atomic_inc(&parent->cl_count);
 430         return clnt;
 431
 432 out_no_path:
 433         rpc_free_iostats(clnt->cl_metrics);
 434 out_no_stats:
 435         rpc_free_clid(clnt);
 436 out_no_clid:
 437         kfree(clnt);
 438 out_err:
 439         rpciod_down();
 440 out_no_rpciod:
 441         xprt_put(xprt);
 442         return ERR_PTR(err);
 443 }
 444
 445 static struct rpc_clnt *rpc_create_xprt(struct rpc_create_args *args,
 446                                         struct rpc_xprt *xprt)
 447 {
 448         struct rpc_clnt *clnt = NULL;
 449
 450         clnt = rpc_new_client(args, xprt, NULL);
 451         if (IS_ERR(clnt))
 452                 return clnt;
 453
 454         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
 455                 int err = rpc_ping(clnt);
 456                 if (err != 0) {
 457                         rpc_shutdown_client(clnt);
 458                         return ERR_PTR(err);
 459                 }
 460         }
 461
 462         clnt->cl_softrtry = 1;
 463         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
 464                 clnt->cl_softrtry = 0;
 465
 466         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
 467                 clnt->cl_autobind = 1;
 468         if (args->flags & RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT)
 469                 clnt->cl_noretranstimeo = 1;
 470         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
 471                 clnt->cl_discrtry = 1;
 472         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
 473                 clnt->cl_chatty = 1;
 474
 475         return clnt;
 476 }
 477
 478 /**
 479  * rpc_create - create an RPC client and transport with one call
 480  * @args: rpc_clnt create argument structure
 481  *
 482  * Creates and initializes an RPC transport and an RPC client.
 483  *
 484  * It can ping the server in order to determine if it is up, and to see if
 485  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
 486  * this behavior so asynchronous tasks can also use rpc_create.
 487  */
 488 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
 489 {
 490         struct rpc_xprt *xprt;
 491         struct xprt_create xprtargs = {
 492                 .net = args->net,
 493                 .ident = args->protocol,
 494                 .srcaddr = args->saddress,
 495                 .dstaddr = args->address,
 496                 .addrlen = args->addrsize,
 497                 .servername = args->servername,
 498                 .bc_xprt = args->bc_xprt,
 499         };
 500         char servername[48];
 501
 502         if (args->bc_xprt) {
 503                 WARN_ON(args->protocol != XPRT_TRANSPORT_BC_TCP);
 504                 xprt = args->bc_xprt->xpt_bc_xprt;
 505                 if (xprt) {
 506                         xprt_get(xprt);
 507                         return rpc_create_xprt(args, xprt);
 508                 }
 509         }
 510
 511         if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
 512                 xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
 513         if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
 514                 xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
 515         /*
 516          * If the caller chooses not to specify a hostname, whip
 517          * up a string representation of the passed-in address.
 518          */
 519         if (xprtargs.servername == NULL) {
 520                 struct sockaddr_un *sun =
 521                                 (struct sockaddr_un *)args->address;
 522                 struct sockaddr_in *sin =
 523                                 (struct sockaddr_in *)args->address;
 524                 struct sockaddr_in6 *sin6 =
 525                                 (struct sockaddr_in6 *)args->address;
 526
 527                 servername[0] = '\0';
 528                 switch (args->address->sa_family) {
 529                 case AF_LOCAL:
 530                         snprintf(servername, sizeof(servername), "%s",
 531                                  sun->sun_path);
 532                         break;
 533                 case AF_INET:
 534                         snprintf(servername, sizeof(servername), "%pI4",
 535                                  &sin->sin_addr.s_addr);
 536                         break;
 537                 case AF_INET6:
 538                         snprintf(servername, sizeof(servername), "%pI6",
 539                                  &sin6->sin6_addr);
 540                         break;
 541                 default:
 542                         /* caller wants default server name, but
 543                          * address family isn't recognized. */
 544                         return ERR_PTR(-EINVAL);
 545                 }
 546                 xprtargs.servername = servername;
 547         }
 548
 549         xprt = xprt_create_transport(&xprtargs);
 550         if (IS_ERR(xprt))
 551                 return (struct rpc_clnt *)xprt;
 552
 553         /*
 554          * By default, kernel RPC client connects from a reserved port.
 555          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
 556          * but it is always enabled for rpciod, which handles the connect
 557          * operation.
 558          */
 559         xprt->resvport = 1;
 560         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
 561                 xprt->resvport = 0;
 562
 563         return rpc_create_xprt(args, xprt);
 564 }
 565 EXPORT_SYMBOL_GPL(rpc_create);
 566
 567 /*
 568  * This function clones the RPC client structure. It allows us to share the
 569  * same transport while varying parameters such as the authentication
 570  * flavour.
 571  */
 572 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
 573                                            struct rpc_clnt *clnt)
 574 {
 575         struct rpc_xprt *xprt;
 576         struct rpc_clnt *new;
 577         int err;
 578
 579         err = -ENOMEM;
 580         rcu_read_lock();
 581         xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
 582         rcu_read_unlock();
 583         if (xprt == NULL)
 584                 goto out_err;
 585         args->servername = xprt->servername;
 586         args->nodename = clnt->cl_nodename;
 587
 588         new = rpc_new_client(args, xprt, clnt);
 589         if (IS_ERR(new)) {
 590                 err = PTR_ERR(new);
 591                 goto out_err;
 592         }
 593
 594         /* Turn off autobind on clones */
 595         new->cl_autobind = 0;
 596         new->cl_softrtry = clnt->cl_softrtry;
 597         new->cl_noretranstimeo = clnt->cl_noretranstimeo;
 598         new->cl_discrtry = clnt->cl_discrtry;
 599         new->cl_chatty = clnt->cl_chatty;
 600         return new;
 601
 602 out_err:
 603         dprintk("RPC:       %s: returned error %d\n", __func__, err);
 604         return ERR_PTR(err);
 605 }
 606
 607 /**
 608  * rpc_clone_client - Clone an RPC client structure
 609  *
 610  * @clnt: RPC client whose parameters are copied
 611  *
 612  * Returns a fresh RPC client or an ERR_PTR.
 613  */
 614 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
 615 {
 616         struct rpc_create_args args = {
 617                 .program        = clnt->cl_program,
 618                 .prognumber     = clnt->cl_prog,
 619                 .version        = clnt->cl_vers,
 620                 .authflavor     = clnt->cl_auth->au_flavor,
 621         };
 622         return __rpc_clone_client(&args, clnt);
 623 }
 624 EXPORT_SYMBOL_GPL(rpc_clone_client);
 625
 626 /**
 627  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
 628  *
 629  * @clnt: RPC client whose parameters are copied
 630  * @flavor: security flavor for new client
 631  *
 632  * Returns a fresh RPC client or an ERR_PTR.
 633  */
 634 struct rpc_clnt *
 635 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
 636 {
 637         struct rpc_create_args args = {
 638                 .program        = clnt->cl_program,
 639                 .prognumber     = clnt->cl_prog,
 640                 .version        = clnt->cl_vers,
 641                 .authflavor     = flavor,
 642         };
 643         return __rpc_clone_client(&args, clnt);
 644 }
 645 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
 646
 647 /**
 648  * rpc_switch_client_transport: switch the RPC transport on the fly
 649  * @clnt: pointer to a struct rpc_clnt
 650  * @args: pointer to the new transport arguments
 651  * @timeout: pointer to the new timeout parameters
 652  *
 653  * This function allows the caller to switch the RPC transport for the
 654  * rpc_clnt structure 'clnt' to allow it to connect to a mirrored NFS
 655  * server, for instance.  It assumes that the caller has ensured that
 656  * there are no active RPC tasks by using some form of locking.
 657  *
 658  * Returns zero if "clnt" is now using the new xprt.  Otherwise a
 659  * negative errno is returned, and "clnt" continues to use the old
 660  * xprt.
 661  */
 662 int rpc_switch_client_transport(struct rpc_clnt *clnt,
 663                 struct xprt_create *args,
 664                 const struct rpc_timeout *timeout)
 665 {
 666         const struct rpc_timeout *old_timeo;
 667         rpc_authflavor_t pseudoflavor;
 668         struct rpc_xprt *xprt, *old;
 669         struct rpc_clnt *parent;
 670         int err;
 671
 672         xprt = xprt_create_transport(args);
 673         if (IS_ERR(xprt)) {
 674                 dprintk("RPC:       failed to create new xprt for clnt %p\n",
 675                         clnt);
 676                 return PTR_ERR(xprt);
 677         }
 678
 679         pseudoflavor = clnt->cl_auth->au_flavor;
 680
 681         old_timeo = clnt->cl_timeout;
 682         old = rpc_clnt_set_transport(clnt, xprt, timeout);
 683
 684         rpc_unregister_client(clnt);
 685         __rpc_clnt_remove_pipedir(clnt);
 686         rpc_clnt_debugfs_unregister(clnt);
 687
 688         /*
 689          * A new transport was created.  "clnt" therefore
 690          * becomes the root of a new cl_parent tree.  clnt's
 691          * children, if it has any, still point to the old xprt.
 692          */
 693         parent = clnt->cl_parent;
 694         clnt->cl_parent = clnt;
 695
 696         /*
 697          * The old rpc_auth cache cannot be re-used.  GSS
 698          * contexts in particular are between a single
 699          * client and server.
 700          */
 701         err = rpc_client_register(clnt, pseudoflavor, NULL);
 702         if (err)
 703                 goto out_revert;
 704
 705         synchronize_rcu();
 706         if (parent != clnt)
 707                 rpc_release_client(parent);
 708         xprt_put(old);
 709         dprintk("RPC:       replaced xprt for clnt %p\n", clnt);
 710         return 0;
 711
 712 out_revert:
 713         rpc_clnt_set_transport(clnt, old, old_timeo);
 714         clnt->cl_parent = parent;
 715         rpc_client_register(clnt, pseudoflavor, NULL);
 716         xprt_put(xprt);
 717         dprintk("RPC:       failed to switch xprt for clnt %p\n", clnt);
 718         return err;
 719 }
 720 EXPORT_SYMBOL_GPL(rpc_switch_client_transport);
 721
 722 /*
 723  * Kill all tasks for the given client.
 724  * XXX: kill their descendants as well?
 725  */
 726 void rpc_killall_tasks(struct rpc_clnt *clnt)
 727 {
 728         struct rpc_task *rovr;
 729
 730
 731         if (list_empty(&clnt->cl_tasks))
 732                 return;
 733         dprintk("RPC:       killing all tasks for client %p\n", clnt);
 734         /*
 735          * Spin lock all_tasks to prevent changes...
 736          */
 737         spin_lock(&clnt->cl_lock);
 738         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
 739                 if (!RPC_IS_ACTIVATED(rovr))
 740                         continue;
 741                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
 742                         rovr->tk_flags |= RPC_TASK_KILLED;
 743                         rpc_exit(rovr, -EIO);
 744                         if (RPC_IS_QUEUED(rovr))
 745                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
 746                                                         rovr);
 747                 }
 748         }
 749         spin_unlock(&clnt->cl_lock);
 750 }
 751 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
 752
 753 /*
 754  * Properly shut down an RPC client, terminating all outstanding
 755  * requests.
 756  */
 757 void rpc_shutdown_client(struct rpc_clnt *clnt)
 758 {
 759         might_sleep();
 760
 761         dprintk_rcu("RPC:       shutting down %s client for %s\n",
 762                         clnt->cl_program->name,
 763                         rcu_dereference(clnt->cl_xprt)->servername);
 764
 765         while (!list_empty(&clnt->cl_tasks)) {
 766                 rpc_killall_tasks(clnt);
 767                 wait_event_timeout(destroy_wait,
 768                         list_empty(&clnt->cl_tasks), 1*HZ);
 769         }
 770
 771         rpc_release_client(clnt);
 772 }
 773 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
 774
 775 /*
 776  * Free an RPC client
 777  */
 778 static struct rpc_clnt *
 779 rpc_free_client(struct rpc_clnt *clnt)
 780 {
 781         struct rpc_clnt *parent = NULL;
 782
 783         dprintk_rcu("RPC:       destroying %s client for %s\n",
 784                         clnt->cl_program->name,
 785                         rcu_dereference(clnt->cl_xprt)->servername);
 786         if (clnt->cl_parent != clnt)
 787                 parent = clnt->cl_parent;
 788         rpc_clnt_debugfs_unregister(clnt);
 789         rpc_clnt_remove_pipedir(clnt);
 790         rpc_unregister_client(clnt);
 791         rpc_free_iostats(clnt->cl_metrics);
 792         clnt->cl_metrics = NULL;
 793         xprt_put(rcu_dereference_raw(clnt->cl_xprt));
 794         rpciod_down();
 795         rpc_free_clid(clnt);
 796         kfree(clnt);
 797         return parent;
 798 }
 799
 800 /*
 801  * Free an RPC client
 802  */
 803 static struct rpc_clnt *
 804 rpc_free_auth(struct rpc_clnt *clnt)
 805 {
 806         if (clnt->cl_auth == NULL)
 807                 return rpc_free_client(clnt);
 808
 809         /*
 810          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
 811          *       release remaining GSS contexts. This mechanism ensures
 812          *       that it can do so safely.
 813          */
 814         atomic_inc(&clnt->cl_count);
 815         rpcauth_release(clnt->cl_auth);
 816         clnt->cl_auth = NULL;
 817         if (atomic_dec_and_test(&clnt->cl_count))
 818                 return rpc_free_client(clnt);
 819         return NULL;
 820 }
 821
 822 /*
 823  * Release reference to the RPC client
 824  */
 825 void
 826 rpc_release_client(struct rpc_clnt *clnt)
 827 {
 828         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
 829
 830         do {
 831                 if (list_empty(&clnt->cl_tasks))
 832                         wake_up(&destroy_wait);
 833                 if (!atomic_dec_and_test(&clnt->cl_count))
 834                         break;
 835                 clnt = rpc_free_auth(clnt);
 836         } while (clnt != NULL);
 837 }
 838 EXPORT_SYMBOL_GPL(rpc_release_client);
 839
 840 /**
 841  * rpc_bind_new_program - bind a new RPC program to an existing client
 842  * @old: old rpc_client
 843  * @program: rpc program to set
 844  * @vers: rpc program version
 845  *
 846  * Clones the rpc client and sets up a new RPC program. This is mainly
 847  * of use for enabling different RPC programs to share the same transport.
 848  * The Sun NFSv2/v3 ACL protocol can do this.
 849  */
 850 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
 851                                       const struct rpc_program *program,
 852                                       u32 vers)
 853 {
 854         struct rpc_create_args args = {
 855                 .program        = program,
 856                 .prognumber     = program->number,
 857                 .version        = vers,
 858                 .authflavor     = old->cl_auth->au_flavor,
 859         };
 860         struct rpc_clnt *clnt;
 861         int err;
 862
 863         clnt = __rpc_clone_client(&args, old);
 864         if (IS_ERR(clnt))
 865                 goto out;
 866         err = rpc_ping(clnt);
 867         if (err != 0) {
 868                 rpc_shutdown_client(clnt);
 869                 clnt = ERR_PTR(err);
 870         }
 871 out:
 872         return clnt;
 873 }
 874 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
 875
 876 void rpc_task_release_client(struct rpc_task *task)
 877 {
 878         struct rpc_clnt *clnt = task->tk_client;
 879
 880         if (clnt != NULL) {
 881                 /* Remove from client task list */
 882                 spin_lock(&clnt->cl_lock);
 883                 list_del(&task->tk_task);
 884                 spin_unlock(&clnt->cl_lock);
 885                 task->tk_client = NULL;
 886
 887                 rpc_release_client(clnt);
 888         }
 889 }
 890
 891 static
 892 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
 893 {
 894         if (clnt != NULL) {
 895                 rpc_task_release_client(task);
 896                 task->tk_client = clnt;
 897                 atomic_inc(&clnt->cl_count);
 898                 if (clnt->cl_softrtry)
 899                         task->tk_flags |= RPC_TASK_SOFT;
 900                 if (clnt->cl_noretranstimeo)
 901                         task->tk_flags |= RPC_TASK_NO_RETRANS_TIMEOUT;
 902                 if (atomic_read(&clnt->cl_swapper))
 903                         task->tk_flags |= RPC_TASK_SWAPPER;
 904                 /* Add to the client's list of all tasks */
 905                 spin_lock(&clnt->cl_lock);
 906                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
 907                 spin_unlock(&clnt->cl_lock);
 908         }
 909 }
 910
 911 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
 912 {
 913         rpc_task_release_client(task);
 914         rpc_task_set_client(task, clnt);
 915 }
 916 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
 917
 918
 919 static void
 920 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
 921 {
 922         if (msg != NULL) {
 923                 task->tk_msg.rpc_proc = msg->rpc_proc;
 924                 task->tk_msg.rpc_argp = msg->rpc_argp;
 925                 task->tk_msg.rpc_resp = msg->rpc_resp;
 926                 if (msg->rpc_cred != NULL)
 927                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
 928         }
 929 }
 930
 931 /*
 932  * Default callback for async RPC calls
 933  */
 934 static void
 935 rpc_default_callback(struct rpc_task *task, void *data)
 936 {
 937 }
 938
 939 static const struct rpc_call_ops rpc_default_ops = {
 940         .rpc_call_done = rpc_default_callback,
 941 };
 942
 943 /**
 944  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
 945  * @task_setup_data: pointer to task initialisation data
 946  */
 947 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
 948 {
 949         struct rpc_task *task;
 950
 951         task = rpc_new_task(task_setup_data);
 952         if (IS_ERR(task))
 953                 goto out;
 954
 955         rpc_task_set_client(task, task_setup_data->rpc_client);
 956         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
 957
 958         if (task->tk_action == NULL)
 959                 rpc_call_start(task);
 960
 961         atomic_inc(&task->tk_count);
 962         rpc_execute(task);
 963 out:
 964         return task;
 965 }
 966 EXPORT_SYMBOL_GPL(rpc_run_task);
 967
 968 /**
 969  * rpc_call_sync - Perform a synchronous RPC call
 970  * @clnt: pointer to RPC client
 971  * @msg: RPC call parameters
 972  * @flags: RPC call flags
 973  */
 974 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
 975 {
 976         struct rpc_task *task;
 977         struct rpc_task_setup task_setup_data = {
 978                 .rpc_client = clnt,
 979                 .rpc_message = msg,
 980                 .callback_ops = &rpc_default_ops,
 981                 .flags = flags,
 982         };
 983         int status;
 984
 985         WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
 986         if (flags & RPC_TASK_ASYNC) {
 987                 rpc_release_calldata(task_setup_data.callback_ops,
 988                         task_setup_data.callback_data);
 989                 return -EINVAL;
 990         }
 991
 992         task = rpc_run_task(&task_setup_data);
 993         if (IS_ERR(task))
 994                 return PTR_ERR(task);
 995         status = task->tk_status;
 996         rpc_put_task(task);
 997         return status;
 998 }
 999 EXPORT_SYMBOL_GPL(rpc_call_sync);
1000
1001 /**
1002  * rpc_call_async - Perform an asynchronous RPC call
1003  * @clnt: pointer to RPC client
1004  * @msg: RPC call parameters
1005  * @flags: RPC call flags
1006  * @tk_ops: RPC call ops
1007  * @data: user call data
1008  */
1009 int
1010 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
1011                const struct rpc_call_ops *tk_ops, void *data)
1012 {
1013         struct rpc_task *task;
1014         struct rpc_task_setup task_setup_data = {
1015                 .rpc_client = clnt,
1016                 .rpc_message = msg,
1017                 .callback_ops = tk_ops,
1018                 .callback_data = data,
1019                 .flags = flags|RPC_TASK_ASYNC,
1020         };
1021
1022         task = rpc_run_task(&task_setup_data);
1023         if (IS_ERR(task))
1024                 return PTR_ERR(task);
1025         rpc_put_task(task);
1026         return 0;
1027 }
1028 EXPORT_SYMBOL_GPL(rpc_call_async);
1029
1030 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1031 /**
1032  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
1033  * rpc_execute against it
1034  * @req: RPC request
1035  */
1036 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req)
1037 {
1038         struct rpc_task *task;
1039         struct xdr_buf *xbufp = &req->rq_snd_buf;
1040         struct rpc_task_setup task_setup_data = {
1041                 .callback_ops = &rpc_default_ops,
1042                 .flags = RPC_TASK_SOFTCONN,
1043         };
1044
1045         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
1046         /*
1047          * Create an rpc_task to send the data
1048          */
1049         task = rpc_new_task(&task_setup_data);
1050         if (IS_ERR(task)) {
1051                 xprt_free_bc_request(req);
1052                 goto out;
1053         }
1054         task->tk_rqstp = req;
1055
1056         /*
1057          * Set up the xdr_buf length.
1058          * This also indicates that the buffer is XDR encoded already.
1059          */
1060         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
1061                         xbufp->tail[0].iov_len;
1062
1063         task->tk_action = call_bc_transmit;
1064         atomic_inc(&task->tk_count);
1065         WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
1066         rpc_execute(task);
1067
1068 out:
1069         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
1070         return task;
1071 }
1072 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1073
1074 void
1075 rpc_call_start(struct rpc_task *task)
1076 {
1077         task->tk_action = call_start;
1078 }
1079 EXPORT_SYMBOL_GPL(rpc_call_start);
1080
1081 /**
1082  * rpc_peeraddr - extract remote peer address from clnt's xprt
1083  * @clnt: RPC client structure
1084  * @buf: target buffer
1085  * @bufsize: length of target buffer
1086  *
1087  * Returns the number of bytes that are actually in the stored address.
1088  */
1089 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
1090 {
1091         size_t bytes;
1092         struct rpc_xprt *xprt;
1093
1094         rcu_read_lock();
1095         xprt = rcu_dereference(clnt->cl_xprt);
1096
1097         bytes = xprt->addrlen;
1098         if (bytes > bufsize)
1099                 bytes = bufsize;
1100         memcpy(buf, &xprt->addr, bytes);
1101         rcu_read_unlock();
1102
1103         return bytes;
1104 }
1105 EXPORT_SYMBOL_GPL(rpc_peeraddr);
1106
1107 /**
1108  * rpc_peeraddr2str - return remote peer address in printable format
1109  * @clnt: RPC client structure
1110  * @format: address format
1111  *
1112  * NB: the lifetime of the memory referenced by the returned pointer is
1113  * the same as the rpc_xprt itself.  As long as the caller uses this
1114  * pointer, it must hold the RCU read lock.
1115  */
1116 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
1117                              enum rpc_display_format_t format)
1118 {
1119         struct rpc_xprt *xprt;
1120
1121         xprt = rcu_dereference(clnt->cl_xprt);
1122
1123         if (xprt->address_strings[format] != NULL)
1124                 return xprt->address_strings[format];
1125         else
1126                 return "unprintable";
1127 }
1128 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
1129
1130 static const struct sockaddr_in rpc_inaddr_loopback = {
1131         .sin_family             = AF_INET,
1132         .sin_addr.s_addr        = htonl(INADDR_ANY),
1133 };
1134
1135 static const struct sockaddr_in6 rpc_in6addr_loopback = {
1136         .sin6_family            = AF_INET6,
1137         .sin6_addr              = IN6ADDR_ANY_INIT,
1138 };
1139
1140 /*
1141  * Try a getsockname() on a connected datagram socket.  Using a
1142  * connected datagram socket prevents leaving a socket in TIME_WAIT.
1143  * This conserves the ephemeral port number space.
1144  *
1145  * Returns zero and fills in "buf" if successful; otherwise, a
1146  * negative errno is returned.
1147  */
1148 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1149                         struct sockaddr *buf, int buflen)
1150 {
1151         struct socket *sock;
1152         int err;
1153
1154         err = __sock_create(net, sap->sa_family,
1155                                 SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1156         if (err < 0) {
1157                 dprintk("RPC:       can't create UDP socket (%d)\n", err);
1158                 goto out;
1159         }
1160
1161         switch (sap->sa_family) {
1162         case AF_INET:
1163                 err = kernel_bind(sock,
1164                                 (struct sockaddr *)&rpc_inaddr_loopback,
1165                                 sizeof(rpc_inaddr_loopback));
1166                 break;
1167         case AF_INET6:
1168                 err = kernel_bind(sock,
1169                                 (struct sockaddr *)&rpc_in6addr_loopback,
1170                                 sizeof(rpc_in6addr_loopback));
1171                 break;
1172         default:
1173                 err = -EAFNOSUPPORT;
1174                 goto out;
1175         }
1176         if (err < 0) {
1177                 dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1178                 goto out_release;
1179         }
1180
1181         err = kernel_connect(sock, sap, salen, 0);
1182         if (err < 0) {
1183                 dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1184                 goto out_release;
1185         }
1186
1187         err = kernel_getsockname(sock, buf, &buflen);
1188         if (err < 0) {
1189                 dprintk("RPC:       getsockname failed (%d)\n", err);
1190                 goto out_release;
1191         }
1192
1193         err = 0;
1194         if (buf->sa_family == AF_INET6) {
1195                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1196                 sin6->sin6_scope_id = 0;
1197         }
1198         dprintk("RPC:       %s succeeded\n", __func__);
1199
1200 out_release:
1201         sock_release(sock);
1202 out:
1203         return err;
1204 }
1205
1206 /*
1207  * Scraping a connected socket failed, so we don't have a useable
1208  * local address.  Fallback: generate an address that will prevent
1209  * the server from calling us back.
1210  *
1211  * Returns zero and fills in "buf" if successful; otherwise, a
1212  * negative errno is returned.
1213  */
1214 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1215 {
1216         switch (family) {
1217         case AF_INET:
1218                 if (buflen < sizeof(rpc_inaddr_loopback))
1219                         return -EINVAL;
1220                 memcpy(buf, &rpc_inaddr_loopback,
1221                                 sizeof(rpc_inaddr_loopback));
1222                 break;
1223         case AF_INET6:
1224                 if (buflen < sizeof(rpc_in6addr_loopback))
1225                         return -EINVAL;
1226                 memcpy(buf, &rpc_in6addr_loopback,
1227                                 sizeof(rpc_in6addr_loopback));
1228         default:
1229                 dprintk("RPC:       %s: address family not supported\n",
1230                         __func__);
1231                 return -EAFNOSUPPORT;
1232         }
1233         dprintk("RPC:       %s: succeeded\n", __func__);
1234         return 0;
1235 }
1236
1237 /**
1238  * rpc_localaddr - discover local endpoint address for an RPC client
1239  * @clnt: RPC client structure
1240  * @buf: target buffer
1241  * @buflen: size of target buffer, in bytes
1242  *
1243  * Returns zero and fills in "buf" and "buflen" if successful;
1244  * otherwise, a negative errno is returned.
1245  *
1246  * This works even if the underlying transport is not currently connected,
1247  * or if the upper layer never previously provided a source address.
1248  *
1249  * The result of this function call is transient: multiple calls in
1250  * succession may give different results, depending on how local
1251  * networking configuration changes over time.
1252  */
1253 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1254 {
1255         struct sockaddr_storage address;
1256         struct sockaddr *sap = (struct sockaddr *)&address;
1257         struct rpc_xprt *xprt;
1258         struct net *net;
1259         size_t salen;
1260         int err;
1261
1262         rcu_read_lock();
1263         xprt = rcu_dereference(clnt->cl_xprt);
1264         salen = xprt->addrlen;
1265         memcpy(sap, &xprt->addr, salen);
1266         net = get_net(xprt->xprt_net);
1267         rcu_read_unlock();
1268
1269         rpc_set_port(sap, 0);
1270         err = rpc_sockname(net, sap, salen, buf, buflen);
1271         put_net(net);
1272         if (err != 0)
1273                 /* Couldn't discover local address, return ANYADDR */
1274                 return rpc_anyaddr(sap->sa_family, buf, buflen);
1275         return 0;
1276 }
1277 EXPORT_SYMBOL_GPL(rpc_localaddr);
1278
1279 void
1280 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1281 {
1282         struct rpc_xprt *xprt;
1283
1284         rcu_read_lock();
1285         xprt = rcu_dereference(clnt->cl_xprt);
1286         if (xprt->ops->set_buffer_size)
1287                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1288         rcu_read_unlock();
1289 }
1290 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1291
1292 /**
1293  * rpc_protocol - Get transport protocol number for an RPC client
1294  * @clnt: RPC client to query
1295  *
1296  */
1297 int rpc_protocol(struct rpc_clnt *clnt)
1298 {
1299         int protocol;
1300
1301         rcu_read_lock();
1302         protocol = rcu_dereference(clnt->cl_xprt)->prot;
1303         rcu_read_unlock();
1304         return protocol;
1305 }
1306 EXPORT_SYMBOL_GPL(rpc_protocol);
1307
1308 /**
1309  * rpc_net_ns - Get the network namespace for this RPC client
1310  * @clnt: RPC client to query
1311  *
1312  */
1313 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1314 {
1315         struct net *ret;
1316
1317         rcu_read_lock();
1318         ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1319         rcu_read_unlock();
1320         return ret;
1321 }
1322 EXPORT_SYMBOL_GPL(rpc_net_ns);
1323
1324 /**
1325  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1326  * @clnt: RPC client to query
1327  *
1328  * For stream transports, this is one RPC record fragment (see RFC
1329  * 1831), as we don't support multi-record requests yet.  For datagram
1330  * transports, this is the size of an IP packet minus the IP, UDP, and
1331  * RPC header sizes.
1332  */
1333 size_t rpc_max_payload(struct rpc_clnt *clnt)
1334 {
1335         size_t ret;
1336
1337         rcu_read_lock();
1338         ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1339         rcu_read_unlock();
1340         return ret;
1341 }
1342 EXPORT_SYMBOL_GPL(rpc_max_payload);
1343
1344 /**
1345  * rpc_get_timeout - Get timeout for transport in units of HZ
1346  * @clnt: RPC client to query
1347  */
1348 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1349 {
1350         unsigned long ret;
1351
1352         rcu_read_lock();
1353         ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1354         rcu_read_unlock();
1355         return ret;
1356 }
1357 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1358
1359 /**
1360  * rpc_force_rebind - force transport to check that remote port is unchanged
1361  * @clnt: client to rebind
1362  *
1363  */
1364 void rpc_force_rebind(struct rpc_clnt *clnt)
1365 {
1366         if (clnt->cl_autobind) {
1367                 rcu_read_lock();
1368                 xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1369                 rcu_read_unlock();
1370         }
1371 }
1372 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1373
1374 /*
1375  * Restart an (async) RPC call from the call_prepare state.
1376  * Usually called from within the exit handler.
1377  */
1378 int
1379 rpc_restart_call_prepare(struct rpc_task *task)
1380 {
1381         if (RPC_ASSASSINATED(task))
1382                 return 0;
1383         task->tk_action = call_start;
1384         task->tk_status = 0;
1385         if (task->tk_ops->rpc_call_prepare != NULL)
1386                 task->tk_action = rpc_prepare_task;
1387         return 1;
1388 }
1389 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1390
1391 /*
1392  * Restart an (async) RPC call. Usually called from within the
1393  * exit handler.
1394  */
1395 int
1396 rpc_restart_call(struct rpc_task *task)
1397 {
1398         if (RPC_ASSASSINATED(task))
1399                 return 0;
1400         task->tk_action = call_start;
1401         task->tk_status = 0;
1402         return 1;
1403 }
1404 EXPORT_SYMBOL_GPL(rpc_restart_call);
1405
1406 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
1407 const char
1408 *rpc_proc_name(const struct rpc_task *task)
1409 {
1410         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1411
1412         if (proc) {
1413                 if (proc->p_name)
1414                         return proc->p_name;
1415                 else
1416                         return "NULL";
1417         } else
1418                 return "no proc";
1419 }
1420 #endif
1421
1422 /*
1423  * 0.  Initial state
1424  *
1425  *     Other FSM states can be visited zero or more times, but
1426  *     this state is visited exactly once for each RPC.
1427  */
1428 static void
1429 call_start(struct rpc_task *task)
1430 {
1431         struct rpc_clnt *clnt = task->tk_client;
1432
1433         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1434                         clnt->cl_program->name, clnt->cl_vers,
1435                         rpc_proc_name(task),
1436                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
1437
1438         /* Increment call count */
1439         task->tk_msg.rpc_proc->p_count++;
1440         clnt->cl_stats->rpccnt++;
1441         task->tk_action = call_reserve;
1442 }
1443
1444 /*
1445  * 1.   Reserve an RPC call slot
1446  */
1447 static void
1448 call_reserve(struct rpc_task *task)
1449 {
1450         dprint_status(task);
1451
1452         task->tk_status  = 0;
1453         task->tk_action  = call_reserveresult;
1454         xprt_reserve(task);
1455 }
1456
1457 static void call_retry_reserve(struct rpc_task *task);
1458
1459 /*
1460  * 1b.  Grok the result of xprt_reserve()
1461  */
1462 static void
1463 call_reserveresult(struct rpc_task *task)
1464 {
1465         int status = task->tk_status;
1466
1467         dprint_status(task);
1468
1469         /*
1470          * After a call to xprt_reserve(), we must have either
1471          * a request slot or else an error status.
1472          */
1473         task->tk_status = 0;
1474         if (status >= 0) {
1475                 if (task->tk_rqstp) {
1476                         task->tk_action = call_refresh;
1477                         return;
1478                 }
1479
1480                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1481                                 __func__, status);
1482                 rpc_exit(task, -EIO);
1483                 return;
1484         }
1485
1486         /*
1487          * Even though there was an error, we may have acquired
1488          * a request slot somehow.  Make sure not to leak it.
1489          */
1490         if (task->tk_rqstp) {
1491                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1492                                 __func__, status);
1493                 xprt_release(task);
1494         }
1495
1496         switch (status) {
1497         case -ENOMEM:
1498                 rpc_delay(task, HZ >> 2);
1499         case -EAGAIN:   /* woken up; retry */
1500                 task->tk_action = call_retry_reserve;
1501                 return;
1502         case -EIO:      /* probably a shutdown */
1503                 break;
1504         default:
1505                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1506                                 __func__, status);
1507                 break;
1508         }
1509         rpc_exit(task, status);
1510 }
1511
1512 /*
1513  * 1c.  Retry reserving an RPC call slot
1514  */
1515 static void
1516 call_retry_reserve(struct rpc_task *task)
1517 {
1518         dprint_status(task);
1519
1520         task->tk_status  = 0;
1521         task->tk_action  = call_reserveresult;
1522         xprt_retry_reserve(task);
1523 }
1524
1525 /*
1526  * 2.   Bind and/or refresh the credentials
1527  */
1528 static void
1529 call_refresh(struct rpc_task *task)
1530 {
1531         dprint_status(task);
1532
1533         task->tk_action = call_refreshresult;
1534         task->tk_status = 0;
1535         task->tk_client->cl_stats->rpcauthrefresh++;
1536         rpcauth_refreshcred(task);
1537 }
1538
1539 /*
1540  * 2a.  Process the results of a credential refresh
1541  */
1542 static void
1543 call_refreshresult(struct rpc_task *task)
1544 {
1545         int status = task->tk_status;
1546
1547         dprint_status(task);
1548
1549         task->tk_status = 0;
1550         task->tk_action = call_refresh;
1551         switch (status) {
1552         case 0:
1553                 if (rpcauth_uptodatecred(task)) {
1554                         task->tk_action = call_allocate;
1555                         return;
1556                 }
1557                 /* Use rate-limiting and a max number of retries if refresh
1558                  * had status 0 but failed to update the cred.
1559                  */
1560         case -ETIMEDOUT:
1561                 rpc_delay(task, 3*HZ);
1562         case -EAGAIN:
1563                 status = -EACCES;
1564         case -EKEYEXPIRED:
1565                 if (!task->tk_cred_retry)
1566                         break;
1567                 task->tk_cred_retry--;
1568                 dprintk("RPC: %5u %s: retry refresh creds\n",
1569                                 task->tk_pid, __func__);
1570                 return;
1571         }
1572         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1573                                 task->tk_pid, __func__, status);
1574         rpc_exit(task, status);
1575 }
1576
1577 /*
1578  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1579  *      (Note: buffer memory is freed in xprt_release).
1580  */
1581 static void
1582 call_allocate(struct rpc_task *task)
1583 {
1584         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1585         struct rpc_rqst *req = task->tk_rqstp;
1586         struct rpc_xprt *xprt = req->rq_xprt;
1587         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1588
1589         dprint_status(task);
1590
1591         task->tk_status = 0;
1592         task->tk_action = call_bind;
1593
1594         if (req->rq_buffer)
1595                 return;
1596
1597         if (proc->p_proc != 0) {
1598                 BUG_ON(proc->p_arglen == 0);
1599                 if (proc->p_decode != NULL)
1600                         BUG_ON(proc->p_replen == 0);
1601         }
1602
1603         /*
1604          * Calculate the size (in quads) of the RPC call
1605          * and reply headers, and convert both values
1606          * to byte sizes.
1607          */
1608         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1609         req->rq_callsize <<= 2;
1610         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1611         req->rq_rcvsize <<= 2;
1612
1613         req->rq_buffer = xprt->ops->buf_alloc(task,
1614                                         req->rq_callsize + req->rq_rcvsize);
1615         if (req->rq_buffer != NULL)
1616                 return;
1617         xprt_inject_disconnect(xprt);
1618
1619         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1620
1621         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1622                 task->tk_action = call_allocate;
1623                 rpc_delay(task, HZ>>4);
1624                 return;
1625         }
1626
1627         rpc_exit(task, -ERESTARTSYS);
1628 }
1629
1630 static inline int
1631 rpc_task_need_encode(struct rpc_task *task)
1632 {
1633         return task->tk_rqstp->rq_snd_buf.len == 0;
1634 }
1635
1636 static inline void
1637 rpc_task_force_reencode(struct rpc_task *task)
1638 {
1639         task->tk_rqstp->rq_snd_buf.len = 0;
1640         task->tk_rqstp->rq_bytes_sent = 0;
1641 }
1642
1643 static inline void
1644 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1645 {
1646         buf->head[0].iov_base = start;
1647         buf->head[0].iov_len = len;
1648         buf->tail[0].iov_len = 0;
1649         buf->page_len = 0;
1650         buf->flags = 0;
1651         buf->len = 0;
1652         buf->buflen = len;
1653 }
1654
1655 /*
1656  * 3.   Encode arguments of an RPC call
1657  */
1658 static void
1659 rpc_xdr_encode(struct rpc_task *task)
1660 {
1661         struct rpc_rqst *req = task->tk_rqstp;
1662         kxdreproc_t     encode;
1663         __be32          *p;
1664
1665         dprint_status(task);
1666
1667         rpc_xdr_buf_init(&req->rq_snd_buf,
1668                          req->rq_buffer,
1669                          req->rq_callsize);
1670         rpc_xdr_buf_init(&req->rq_rcv_buf,
1671                          (char *)req->rq_buffer + req->rq_callsize,
1672                          req->rq_rcvsize);
1673
1674         p = rpc_encode_header(task);
1675         if (p == NULL) {
1676                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1677                 rpc_exit(task, -EIO);
1678                 return;
1679         }
1680
1681         encode = task->tk_msg.rpc_proc->p_encode;
1682         if (encode == NULL)
1683                 return;
1684
1685         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1686                         task->tk_msg.rpc_argp);
1687 }
1688
1689 /*
1690  * 4.   Get the server port number if not yet set
1691  */
1692 static void
1693 call_bind(struct rpc_task *task)
1694 {
1695         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1696
1697         dprint_status(task);
1698
1699         task->tk_action = call_connect;
1700         if (!xprt_bound(xprt)) {
1701                 task->tk_action = call_bind_status;
1702                 task->tk_timeout = xprt->bind_timeout;
1703                 xprt->ops->rpcbind(task);
1704         }
1705 }
1706
1707 /*
1708  * 4a.  Sort out bind result
1709  */
1710 static void
1711 call_bind_status(struct rpc_task *task)
1712 {
1713         int status = -EIO;
1714
1715         if (task->tk_status >= 0) {
1716                 dprint_status(task);
1717                 task->tk_status = 0;
1718                 task->tk_action = call_connect;
1719                 return;
1720         }
1721
1722         trace_rpc_bind_status(task);
1723         switch (task->tk_status) {
1724         case -ENOMEM:
1725                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1726                 rpc_delay(task, HZ >> 2);
1727                 goto retry_timeout;
1728         case -EACCES:
1729                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1730                                 "unavailable\n", task->tk_pid);
1731                 /* fail immediately if this is an RPC ping */
1732                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1733                         status = -EOPNOTSUPP;
1734                         break;
1735                 }
1736                 if (task->tk_rebind_retry == 0)
1737                         break;
1738                 task->tk_rebind_retry--;
1739                 rpc_delay(task, 3*HZ);
1740                 goto retry_timeout;
1741         case -ETIMEDOUT:
1742                 dprintk("RPC: %5u rpcbind request timed out\n",
1743                                 task->tk_pid);
1744                 goto retry_timeout;
1745         case -EPFNOSUPPORT:
1746                 /* server doesn't support any rpcbind version we know of */
1747                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1748                                 task->tk_pid);
1749                 break;
1750         case -EPROTONOSUPPORT:
1751                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1752                                 task->tk_pid);
1753                 goto retry_timeout;
1754         case -ECONNREFUSED:             /* connection problems */
1755         case -ECONNRESET:
1756         case -ECONNABORTED:
1757         case -ENOTCONN:
1758         case -EHOSTDOWN:
1759         case -EHOSTUNREACH:
1760         case -ENETUNREACH:
1761         case -ENOBUFS:
1762         case -EPIPE:
1763                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1764                                 task->tk_pid, task->tk_status);
1765                 if (!RPC_IS_SOFTCONN(task)) {
1766                         rpc_delay(task, 5*HZ);
1767                         goto retry_timeout;
1768                 }
1769                 status = task->tk_status;
1770                 break;
1771         default:
1772                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1773                                 task->tk_pid, -task->tk_status);
1774         }
1775
1776         rpc_exit(task, status);
1777         return;
1778
1779 retry_timeout:
1780         task->tk_status = 0;
1781         task->tk_action = call_timeout;
1782 }
1783
1784 /*
1785  * 4b.  Connect to the RPC server
1786  */
1787 static void
1788 call_connect(struct rpc_task *task)
1789 {
1790         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1791
1792         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1793                         task->tk_pid, xprt,
1794                         (xprt_connected(xprt) ? "is" : "is not"));
1795
1796         task->tk_action = call_transmit;
1797         if (!xprt_connected(xprt)) {
1798                 task->tk_action = call_connect_status;
1799                 if (task->tk_status < 0)
1800                         return;
1801                 if (task->tk_flags & RPC_TASK_NOCONNECT) {
1802                         rpc_exit(task, -ENOTCONN);
1803                         return;
1804                 }
1805                 xprt_connect(task);
1806         }
1807 }
1808
1809 /*
1810  * 4c.  Sort out connect result
1811  */
1812 static void
1813 call_connect_status(struct rpc_task *task)
1814 {
1815         struct rpc_clnt *clnt = task->tk_client;
1816         int status = task->tk_status;
1817
1818         dprint_status(task);
1819
1820         trace_rpc_connect_status(task, status);
1821         task->tk_status = 0;
1822         switch (status) {
1823         case -ECONNREFUSED:
1824         case -ECONNRESET:
1825         case -ECONNABORTED:
1826         case -ENETUNREACH:
1827         case -EHOSTUNREACH:
1828         case -EADDRINUSE:
1829         case -ENOBUFS:
1830         case -EPIPE:
1831                 if (RPC_IS_SOFTCONN(task))
1832                         break;
1833                 /* retry with existing socket, after a delay */
1834                 rpc_delay(task, 3*HZ);
1835         case -EAGAIN:
1836                 /* Check for timeouts before looping back to call_bind */
1837         case -ETIMEDOUT:
1838                 task->tk_action = call_timeout;
1839                 return;
1840         case 0:
1841                 clnt->cl_stats->netreconn++;
1842                 task->tk_action = call_transmit;
1843                 return;
1844         }
1845         rpc_exit(task, status);
1846 }
1847
1848 /*
1849  * 5.   Transmit the RPC request, and wait for reply
1850  */
1851 static void
1852 call_transmit(struct rpc_task *task)
1853 {
1854         int is_retrans = RPC_WAS_SENT(task);
1855
1856         dprint_status(task);
1857
1858         task->tk_action = call_status;
1859         if (task->tk_status < 0)
1860                 return;
1861         if (!xprt_prepare_transmit(task))
1862                 return;
1863         task->tk_action = call_transmit_status;
1864         /* Encode here so that rpcsec_gss can use correct sequence number. */
1865         if (rpc_task_need_encode(task)) {
1866                 rpc_xdr_encode(task);
1867                 /* Did the encode result in an error condition? */
1868                 if (task->tk_status != 0) {
1869                         /* Was the error nonfatal? */
1870                         if (task->tk_status == -EAGAIN)
1871                                 rpc_delay(task, HZ >> 4);
1872                         else
1873                                 rpc_exit(task, task->tk_status);
1874                         return;
1875                 }
1876         }
1877         xprt_transmit(task);
1878         if (task->tk_status < 0)
1879                 return;
1880         if (is_retrans)
1881                 task->tk_client->cl_stats->rpcretrans++;
1882         /*
1883          * On success, ensure that we call xprt_end_transmit() before sleeping
1884          * in order to allow access to the socket to other RPC requests.
1885          */
1886         call_transmit_status(task);
1887         if (rpc_reply_expected(task))
1888                 return;
1889         task->tk_action = rpc_exit_task;
1890         rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1891 }
1892
1893 /*
1894  * 5a.  Handle cleanup after a transmission
1895  */
1896 static void
1897 call_transmit_status(struct rpc_task *task)
1898 {
1899         task->tk_action = call_status;
1900
1901         /*
1902          * Common case: success.  Force the compiler to put this
1903          * test first.
1904          */
1905         if (task->tk_status == 0) {
1906                 xprt_end_transmit(task);
1907                 rpc_task_force_reencode(task);
1908                 return;
1909         }
1910
1911         switch (task->tk_status) {
1912         case -EAGAIN:
1913         case -ENOBUFS:
1914                 break;
1915         default:
1916                 dprint_status(task);
1917                 xprt_end_transmit(task);
1918                 rpc_task_force_reencode(task);
1919                 break;
1920                 /*
1921                  * Special cases: if we've been waiting on the
1922                  * socket's write_space() callback, or if the
1923                  * socket just returned a connection error,
1924                  * then hold onto the transport lock.
1925                  */
1926         case -ECONNREFUSED:
1927         case -EHOSTDOWN:
1928         case -EHOSTUNREACH:
1929         case -ENETUNREACH:
1930         case -EPERM:
1931                 if (RPC_IS_SOFTCONN(task)) {
1932                         xprt_end_transmit(task);
1933                         rpc_exit(task, task->tk_status);
1934                         break;
1935                 }
1936         case -ECONNRESET:
1937         case -ECONNABORTED:
1938         case -EADDRINUSE:
1939         case -ENOTCONN:
1940         case -EPIPE:
1941                 rpc_task_force_reencode(task);
1942         }
1943 }
1944
1945 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1946 /*
1947  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1948  * addition, disconnect on connectivity errors.
1949  */
1950 static void
1951 call_bc_transmit(struct rpc_task *task)
1952 {
1953         struct rpc_rqst *req = task->tk_rqstp;
1954
1955         if (!xprt_prepare_transmit(task))
1956                 goto out_retry;
1957
1958         if (task->tk_status < 0) {
1959                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1960                         "error: %d\n", task->tk_status);
1961                 goto out_done;
1962         }
1963         if (req->rq_connect_cookie != req->rq_xprt->connect_cookie)
1964                 req->rq_bytes_sent = 0;
1965
1966         xprt_transmit(task);
1967
1968         if (task->tk_status == -EAGAIN)
1969                 goto out_nospace;
1970
1971         xprt_end_transmit(task);
1972         dprint_status(task);
1973         switch (task->tk_status) {
1974         case 0:
1975                 /* Success */
1976         case -EHOSTDOWN:
1977         case -EHOSTUNREACH:
1978         case -ENETUNREACH:
1979         case -ECONNRESET:
1980         case -ECONNREFUSED:
1981         case -EADDRINUSE:
1982         case -ENOTCONN:
1983         case -EPIPE:
1984                 break;
1985         case -ETIMEDOUT:
1986                 /*
1987                  * Problem reaching the server.  Disconnect and let the
1988                  * forechannel reestablish the connection.  The server will
1989                  * have to retransmit the backchannel request and we'll
1990                  * reprocess it.  Since these ops are idempotent, there's no
1991                  * need to cache our reply at this time.
1992                  */
1993                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1994                         "error: %d\n", task->tk_status);
1995                 xprt_conditional_disconnect(req->rq_xprt,
1996                         req->rq_connect_cookie);
1997                 break;
1998         default:
1999                 /*
2000                  * We were unable to reply and will have to drop the
2001                  * request.  The server should reconnect and retransmit.
2002                  */
2003                 WARN_ON_ONCE(task->tk_status == -EAGAIN);
2004                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
2005                         "error: %d\n", task->tk_status);
2006                 break;
2007         }
2008         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
2009 out_done:
2010         task->tk_action = rpc_exit_task;
2011         return;
2012 out_nospace:
2013         req->rq_connect_cookie = req->rq_xprt->connect_cookie;
2014 out_retry:
2015         task->tk_status = 0;
2016 }
2017 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
2018
2019 /*
2020  * 6.   Sort out the RPC call status
2021  */
2022 static void
2023 call_status(struct rpc_task *task)
2024 {
2025         struct rpc_clnt *clnt = task->tk_client;
2026         struct rpc_rqst *req = task->tk_rqstp;
2027         int             status;
2028
2029         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
2030                 task->tk_status = req->rq_reply_bytes_recvd;
2031
2032         dprint_status(task);
2033
2034         status = task->tk_status;
2035         if (status >= 0) {
2036                 task->tk_action = call_decode;
2037                 return;
2038         }
2039
2040         trace_rpc_call_status(task);
2041         task->tk_status = 0;
2042         switch(status) {
2043         case -EHOSTDOWN:
2044         case -EHOSTUNREACH:
2045         case -ENETUNREACH:
2046         case -EPERM:
2047                 if (RPC_IS_SOFTCONN(task)) {
2048                         rpc_exit(task, status);
2049                         break;
2050                 }
2051                 /*
2052                  * Delay any retries for 3 seconds, then handle as if it
2053                  * were a timeout.
2054                  */
2055                 rpc_delay(task, 3*HZ);
2056         case -ETIMEDOUT:
2057                 task->tk_action = call_timeout;
2058                 if (!(task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT)
2059                     && task->tk_client->cl_discrtry)
2060                         xprt_conditional_disconnect(req->rq_xprt,
2061                                         req->rq_connect_cookie);
2062                 break;
2063         case -ECONNREFUSED:
2064         case -ECONNRESET:
2065         case -ECONNABORTED:
2066                 rpc_force_rebind(clnt);
2067         case -EADDRINUSE:
2068                 rpc_delay(task, 3*HZ);
2069         case -EPIPE:
2070         case -ENOTCONN:
2071                 task->tk_action = call_bind;
2072                 break;
2073         case -ENOBUFS:
2074                 rpc_delay(task, HZ>>2);
2075         case -EAGAIN:
2076                 task->tk_action = call_transmit;
2077                 break;
2078         case -EIO:
2079                 /* shutdown or soft timeout */
2080                 rpc_exit(task, status);
2081                 break;
2082         default:
2083                 if (clnt->cl_chatty)
2084                         printk("%s: RPC call returned error %d\n",
2085                                clnt->cl_program->name, -status);
2086                 rpc_exit(task, status);
2087         }
2088 }
2089
2090 /*
2091  * 6a.  Handle RPC timeout
2092  *      We do not release the request slot, so we keep using the
2093  *      same XID for all retransmits.
2094  */
2095 static void
2096 call_timeout(struct rpc_task *task)
2097 {
2098         struct rpc_clnt *clnt = task->tk_client;
2099
2100         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
2101                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
2102                 goto retry;
2103         }
2104
2105         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
2106         task->tk_timeouts++;
2107
2108         if (RPC_IS_SOFTCONN(task)) {
2109                 rpc_exit(task, -ETIMEDOUT);
2110                 return;
2111         }
2112         if (RPC_IS_SOFT(task)) {
2113                 if (clnt->cl_chatty) {
2114                         rcu_read_lock();
2115                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
2116                                 clnt->cl_program->name,
2117                                 rcu_dereference(clnt->cl_xprt)->servername);
2118                         rcu_read_unlock();
2119                 }
2120                 if (task->tk_flags & RPC_TASK_TIMEOUT)
2121                         rpc_exit(task, -ETIMEDOUT);
2122                 else
2123                         rpc_exit(task, -EIO);
2124                 return;
2125         }
2126
2127         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
2128                 task->tk_flags |= RPC_CALL_MAJORSEEN;
2129                 if (clnt->cl_chatty) {
2130                         rcu_read_lock();
2131                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
2132                         clnt->cl_program->name,
2133                         rcu_dereference(clnt->cl_xprt)->servername);
2134                         rcu_read_unlock();
2135                 }
2136         }
2137         rpc_force_rebind(clnt);
2138         /*
2139          * Did our request time out due to an RPCSEC_GSS out-of-sequence
2140          * event? RFC2203 requires the server to drop all such requests.
2141          */
2142         rpcauth_invalcred(task);
2143
2144 retry:
2145         task->tk_action = call_bind;
2146         task->tk_status = 0;
2147 }
2148
2149 /*
2150  * 7.   Decode the RPC reply
2151  */
2152 static void
2153 call_decode(struct rpc_task *task)
2154 {
2155         struct rpc_clnt *clnt = task->tk_client;
2156         struct rpc_rqst *req = task->tk_rqstp;
2157         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
2158         __be32          *p;
2159
2160         dprint_status(task);
2161
2162         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
2163                 if (clnt->cl_chatty) {
2164                         rcu_read_lock();
2165                         printk(KERN_NOTICE "%s: server %s OK\n",
2166                                 clnt->cl_program->name,
2167                                 rcu_dereference(clnt->cl_xprt)->servername);
2168                         rcu_read_unlock();
2169                 }
2170                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
2171         }
2172
2173         /*
2174          * Ensure that we see all writes made by xprt_complete_rqst()
2175          * before it changed req->rq_reply_bytes_recvd.
2176          */
2177         smp_rmb();
2178         req->rq_rcv_buf.len = req->rq_private_buf.len;
2179
2180         /* Check that the softirq receive buffer is valid */
2181         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
2182                                 sizeof(req->rq_rcv_buf)) != 0);
2183
2184         if (req->rq_rcv_buf.len < 12) {
2185                 if (!RPC_IS_SOFT(task)) {
2186                         task->tk_action = call_bind;
2187                         goto out_retry;
2188                 }
2189                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2190                                 clnt->cl_program->name, task->tk_status);
2191                 task->tk_action = call_timeout;
2192                 goto out_retry;
2193         }
2194
2195         p = rpc_verify_header(task);
2196         if (IS_ERR(p)) {
2197                 if (p == ERR_PTR(-EAGAIN))
2198                         goto out_retry;
2199                 return;
2200         }
2201
2202         task->tk_action = rpc_exit_task;
2203
2204         if (decode) {
2205                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2206                                                       task->tk_msg.rpc_resp);
2207         }
2208         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2209                         task->tk_status);
2210         return;
2211 out_retry:
2212         task->tk_status = 0;
2213         /* Note: rpc_verify_header() may have freed the RPC slot */
2214         if (task->tk_rqstp == req) {
2215                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2216                 if (task->tk_client->cl_discrtry)
2217                         xprt_conditional_disconnect(req->rq_xprt,
2218                                         req->rq_connect_cookie);
2219         }
2220 }
2221
2222 static __be32 *
2223 rpc_encode_header(struct rpc_task *task)
2224 {
2225         struct rpc_clnt *clnt = task->tk_client;
2226         struct rpc_rqst *req = task->tk_rqstp;
2227         __be32          *p = req->rq_svec[0].iov_base;
2228
2229         /* FIXME: check buffer size? */
2230
2231         p = xprt_skip_transport_header(req->rq_xprt, p);
2232         *p++ = req->rq_xid;             /* XID */
2233         *p++ = htonl(RPC_CALL);         /* CALL */
2234         *p++ = htonl(RPC_VERSION);      /* RPC version */
2235         *p++ = htonl(clnt->cl_prog);    /* program number */
2236         *p++ = htonl(clnt->cl_vers);    /* program version */
2237         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
2238         p = rpcauth_marshcred(task, p);
2239         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2240         return p;
2241 }
2242
2243 static __be32 *
2244 rpc_verify_header(struct rpc_task *task)
2245 {
2246         struct rpc_clnt *clnt = task->tk_client;
2247         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2248         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2249         __be32  *p = iov->iov_base;
2250         u32 n;
2251         int error = -EACCES;
2252
2253         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2254                 /* RFC-1014 says that the representation of XDR data must be a
2255                  * multiple of four bytes
2256                  * - if it isn't pointer subtraction in the NFS client may give
2257                  *   undefined results
2258                  */
2259                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
2260                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2261                        task->tk_rqstp->rq_rcv_buf.len);
2262                 error = -EIO;
2263                 goto out_err;
2264         }
2265         if ((len -= 3) < 0)
2266                 goto out_overflow;
2267
2268         p += 1; /* skip XID */
2269         if ((n = ntohl(*p++)) != RPC_REPLY) {
2270                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2271                         task->tk_pid, __func__, n);
2272                 error = -EIO;
2273                 goto out_garbage;
2274         }
2275
2276         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2277                 if (--len < 0)
2278                         goto out_overflow;
2279                 switch ((n = ntohl(*p++))) {
2280                 case RPC_AUTH_ERROR:
2281                         break;
2282                 case RPC_MISMATCH:
2283                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2284                                 task->tk_pid, __func__);
2285                         error = -EPROTONOSUPPORT;
2286                         goto out_err;
2287                 default:
2288                         dprintk("RPC: %5u %s: RPC call rejected, "
2289                                 "unknown error: %x\n",
2290                                 task->tk_pid, __func__, n);
2291                         error = -EIO;
2292                         goto out_err;
2293                 }
2294                 if (--len < 0)
2295                         goto out_overflow;
2296                 switch ((n = ntohl(*p++))) {
2297                 case RPC_AUTH_REJECTEDCRED:
2298                 case RPC_AUTH_REJECTEDVERF:
2299                 case RPCSEC_GSS_CREDPROBLEM:
2300                 case RPCSEC_GSS_CTXPROBLEM:
2301                         if (!task->tk_cred_retry)
2302                                 break;
2303                         task->tk_cred_retry--;
2304                         dprintk("RPC: %5u %s: retry stale creds\n",
2305                                         task->tk_pid, __func__);
2306                         rpcauth_invalcred(task);
2307                         /* Ensure we obtain a new XID! */
2308                         xprt_release(task);
2309                         task->tk_action = call_reserve;
2310                         goto out_retry;
2311                 case RPC_AUTH_BADCRED:
2312                 case RPC_AUTH_BADVERF:
2313                         /* possibly garbled cred/verf? */
2314                         if (!task->tk_garb_retry)
2315                                 break;
2316                         task->tk_garb_retry--;
2317                         dprintk("RPC: %5u %s: retry garbled creds\n",
2318                                         task->tk_pid, __func__);
2319                         task->tk_action = call_bind;
2320                         goto out_retry;
2321                 case RPC_AUTH_TOOWEAK:
2322                         rcu_read_lock();
2323                         printk(KERN_NOTICE "RPC: server %s requires stronger "
2324                                "authentication.\n",
2325                                rcu_dereference(clnt->cl_xprt)->servername);
2326                         rcu_read_unlock();
2327                         break;
2328                 default:
2329                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
2330                                         task->tk_pid, __func__, n);
2331                         error = -EIO;
2332                 }
2333                 dprintk("RPC: %5u %s: call rejected %d\n",
2334                                 task->tk_pid, __func__, n);
2335                 goto out_err;
2336         }
2337         p = rpcauth_checkverf(task, p);
2338         if (IS_ERR(p)) {
2339                 error = PTR_ERR(p);
2340                 dprintk("RPC: %5u %s: auth check failed with %d\n",
2341                                 task->tk_pid, __func__, error);
2342                 goto out_garbage;               /* bad verifier, retry */
2343         }
2344         len = p - (__be32 *)iov->iov_base - 1;
2345         if (len < 0)
2346                 goto out_overflow;
2347         switch ((n = ntohl(*p++))) {
2348         case RPC_SUCCESS:
2349                 return p;
2350         case RPC_PROG_UNAVAIL:
2351                 dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2352                                 "by server %s\n", task->tk_pid, __func__,
2353                                 (unsigned int)clnt->cl_prog,
2354                                 rcu_dereference(clnt->cl_xprt)->servername);
2355                 error = -EPFNOSUPPORT;
2356                 goto out_err;
2357         case RPC_PROG_MISMATCH:
2358                 dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2359                                 "by server %s\n", task->tk_pid, __func__,
2360                                 (unsigned int)clnt->cl_prog,
2361                                 (unsigned int)clnt->cl_vers,
2362                                 rcu_dereference(clnt->cl_xprt)->servername);
2363                 error = -EPROTONOSUPPORT;
2364                 goto out_err;
2365         case RPC_PROC_UNAVAIL:
2366                 dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2367                                 "version %u on server %s\n",
2368                                 task->tk_pid, __func__,
2369                                 rpc_proc_name(task),
2370                                 clnt->cl_prog, clnt->cl_vers,
2371                                 rcu_dereference(clnt->cl_xprt)->servername);
2372                 error = -EOPNOTSUPP;
2373                 goto out_err;
2374         case RPC_GARBAGE_ARGS:
2375                 dprintk("RPC: %5u %s: server saw garbage\n",
2376                                 task->tk_pid, __func__);
2377                 break;                  /* retry */
2378         default:
2379                 dprintk("RPC: %5u %s: server accept status: %x\n",
2380                                 task->tk_pid, __func__, n);
2381                 /* Also retry */
2382         }
2383
2384 out_garbage:
2385         clnt->cl_stats->rpcgarbage++;
2386         if (task->tk_garb_retry) {
2387                 task->tk_garb_retry--;
2388                 dprintk("RPC: %5u %s: retrying\n",
2389                                 task->tk_pid, __func__);
2390                 task->tk_action = call_bind;
2391 out_retry:
2392                 return ERR_PTR(-EAGAIN);
2393         }
2394 out_err:
2395         rpc_exit(task, error);
2396         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2397                         __func__, error);
2398         return ERR_PTR(error);
2399 out_overflow:
2400         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2401                         __func__);
2402         goto out_garbage;
2403 }
2404
2405 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2406 {
2407 }
2408
2409 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2410 {
2411         return 0;
2412 }
2413
2414 static struct rpc_procinfo rpcproc_null = {
2415         .p_encode = rpcproc_encode_null,
2416         .p_decode = rpcproc_decode_null,
2417 };
2418
2419 static int rpc_ping(struct rpc_clnt *clnt)
2420 {
2421         struct rpc_message msg = {
2422                 .rpc_proc = &rpcproc_null,
2423         };
2424         int err;
2425         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2426         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2427         put_rpccred(msg.rpc_cred);
2428         return err;
2429 }
2430
2431 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2432 {
2433         struct rpc_message msg = {
2434                 .rpc_proc = &rpcproc_null,
2435                 .rpc_cred = cred,
2436         };
2437         struct rpc_task_setup task_setup_data = {
2438                 .rpc_client = clnt,
2439                 .rpc_message = &msg,
2440                 .callback_ops = &rpc_default_ops,
2441                 .flags = flags,
2442         };
2443         return rpc_run_task(&task_setup_data);
2444 }
2445 EXPORT_SYMBOL_GPL(rpc_call_null);
2446
2447 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
2448 static void rpc_show_header(void)
2449 {
2450         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2451                 "-timeout ---ops--\n");
2452 }
2453
2454 static void rpc_show_task(const struct rpc_clnt *clnt,
2455                           const struct rpc_task *task)
2456 {
2457         const char *rpc_waitq = "none";
2458
2459         if (RPC_IS_QUEUED(task))
2460                 rpc_waitq = rpc_qname(task->tk_waitqueue);
2461
2462         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2463                 task->tk_pid, task->tk_flags, task->tk_status,
2464                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2465                 clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
2466                 task->tk_action, rpc_waitq);
2467 }
2468
2469 void rpc_show_tasks(struct net *net)
2470 {
2471         struct rpc_clnt *clnt;
2472         struct rpc_task *task;
2473         int header = 0;
2474         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2475
2476         spin_lock(&sn->rpc_client_lock);
2477         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2478                 spin_lock(&clnt->cl_lock);
2479                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2480                         if (!header) {
2481                                 rpc_show_header();
2482                                 header++;
2483                         }
2484                         rpc_show_task(clnt, task);
2485                 }
2486                 spin_unlock(&clnt->cl_lock);
2487         }
2488         spin_unlock(&sn->rpc_client_lock);
2489 }
2490 #endif
2491
2492 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
2493 int
2494 rpc_clnt_swap_activate(struct rpc_clnt *clnt)
2495 {
2496         int ret = 0;
2497         struct rpc_xprt *xprt;
2498
2499         if (atomic_inc_return(&clnt->cl_swapper) == 1) {
2500 retry:
2501                 rcu_read_lock();
2502                 xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
2503                 rcu_read_unlock();
2504                 if (!xprt) {
2505                         /*
2506                          * If we didn't get a reference, then we likely are
2507                          * racing with a migration event. Wait for a grace
2508                          * period and try again.
2509                          */
2510                         synchronize_rcu();
2511                         goto retry;
2512                 }
2513
2514                 ret = xprt_enable_swap(xprt);
2515                 xprt_put(xprt);
2516         }
2517         return ret;
2518 }
2519 EXPORT_SYMBOL_GPL(rpc_clnt_swap_activate);
2520
2521 void
2522 rpc_clnt_swap_deactivate(struct rpc_clnt *clnt)
2523 {
2524         struct rpc_xprt *xprt;
2525
2526         if (atomic_dec_if_positive(&clnt->cl_swapper) == 0) {
2527 retry:
2528                 rcu_read_lock();
2529                 xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
2530                 rcu_read_unlock();
2531                 if (!xprt) {
2532                         /*
2533                          * If we didn't get a reference, then we likely are
2534                          * racing with a migration event. Wait for a grace
2535                          * period and try again.
2536                          */
2537                         synchronize_rcu();
2538                         goto retry;
2539                 }
2540
2541                 xprt_disable_swap(xprt);
2542                 xprt_put(xprt);
2543         }
2544 }
2545 EXPORT_SYMBOL_GPL(rpc_clnt_swap_deactivate);
2546 #endif /* CONFIG_SUNRPC_SWAP */