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Linux/net/sunrpc/clnt.c

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  1 /*
  2  *  linux/net/sunrpc/clnt.c
  3  *
  4  *  This file contains the high-level RPC interface.
  5  *  It is modeled as a finite state machine to support both synchronous
  6  *  and asynchronous requests.
  7  *
  8  *  -   RPC header generation and argument serialization.
  9  *  -   Credential refresh.
 10  *  -   TCP connect handling.
 11  *  -   Retry of operation when it is suspected the operation failed because
 12  *      of uid squashing on the server, or when the credentials were stale
 13  *      and need to be refreshed, or when a packet was damaged in transit.
 14  *      This may be have to be moved to the VFS layer.
 15  *
 16  *  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/utsname.h>
 29 #include <linux/workqueue.h>
 30 #include <linux/in.h>
 31 #include <linux/in6.h>
 32 #include <linux/un.h>
 33 #include <linux/rcupdate.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 #ifdef RPC_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         if (clnt->cl_dentry) {
106                 if (clnt->cl_auth && clnt->cl_auth->au_ops->pipes_destroy)
107                         clnt->cl_auth->au_ops->pipes_destroy(clnt->cl_auth);
108                 rpc_remove_client_dir(clnt->cl_dentry);
109         }
110         clnt->cl_dentry = NULL;
111 }
112 
113 static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
114 {
115         struct net *net = rpc_net_ns(clnt);
116         struct super_block *pipefs_sb;
117 
118         pipefs_sb = rpc_get_sb_net(net);
119         if (pipefs_sb) {
120                 __rpc_clnt_remove_pipedir(clnt);
121                 rpc_put_sb_net(net);
122         }
123 }
124 
125 static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
126                                     struct rpc_clnt *clnt,
127                                     const char *dir_name)
128 {
129         static uint32_t clntid;
130         char name[15];
131         struct qstr q = { .name = name };
132         struct dentry *dir, *dentry;
133         int error;
134 
135         dir = rpc_d_lookup_sb(sb, dir_name);
136         if (dir == NULL) {
137                 pr_info("RPC: pipefs directory doesn't exist: %s\n", dir_name);
138                 return dir;
139         }
140         for (;;) {
141                 q.len = snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
142                 name[sizeof(name) - 1] = '\0';
143                 q.hash = full_name_hash(q.name, q.len);
144                 dentry = rpc_create_client_dir(dir, &q, clnt);
145                 if (!IS_ERR(dentry))
146                         break;
147                 error = PTR_ERR(dentry);
148                 if (error != -EEXIST) {
149                         printk(KERN_INFO "RPC: Couldn't create pipefs entry"
150                                         " %s/%s, error %d\n",
151                                         dir_name, name, error);
152                         break;
153                 }
154         }
155         dput(dir);
156         return dentry;
157 }
158 
159 static int
160 rpc_setup_pipedir(struct rpc_clnt *clnt, const char *dir_name)
161 {
162         struct net *net = rpc_net_ns(clnt);
163         struct super_block *pipefs_sb;
164         struct dentry *dentry;
165 
166         clnt->cl_dentry = NULL;
167         if (dir_name == NULL)
168                 return 0;
169         pipefs_sb = rpc_get_sb_net(net);
170         if (!pipefs_sb)
171                 return 0;
172         dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt, dir_name);
173         rpc_put_sb_net(net);
174         if (IS_ERR(dentry))
175                 return PTR_ERR(dentry);
176         clnt->cl_dentry = dentry;
177         return 0;
178 }
179 
180 static inline int rpc_clnt_skip_event(struct rpc_clnt *clnt, unsigned long event)
181 {
182         if (((event == RPC_PIPEFS_MOUNT) && clnt->cl_dentry) ||
183             ((event == RPC_PIPEFS_UMOUNT) && !clnt->cl_dentry))
184                 return 1;
185         return 0;
186 }
187 
188 static int __rpc_clnt_handle_event(struct rpc_clnt *clnt, unsigned long event,
189                                    struct super_block *sb)
190 {
191         struct dentry *dentry;
192         int err = 0;
193 
194         switch (event) {
195         case RPC_PIPEFS_MOUNT:
196                 dentry = rpc_setup_pipedir_sb(sb, clnt,
197                                               clnt->cl_program->pipe_dir_name);
198                 if (!dentry)
199                         return -ENOENT;
200                 if (IS_ERR(dentry))
201                         return PTR_ERR(dentry);
202                 clnt->cl_dentry = dentry;
203                 if (clnt->cl_auth->au_ops->pipes_create) {
204                         err = clnt->cl_auth->au_ops->pipes_create(clnt->cl_auth);
205                         if (err)
206                                 __rpc_clnt_remove_pipedir(clnt);
207                 }
208                 break;
209         case RPC_PIPEFS_UMOUNT:
210                 __rpc_clnt_remove_pipedir(clnt);
211                 break;
212         default:
213                 printk(KERN_ERR "%s: unknown event: %ld\n", __func__, event);
214                 return -ENOTSUPP;
215         }
216         return err;
217 }
218 
219 static int __rpc_pipefs_event(struct rpc_clnt *clnt, unsigned long event,
220                                 struct super_block *sb)
221 {
222         int error = 0;
223 
224         for (;; clnt = clnt->cl_parent) {
225                 if (!rpc_clnt_skip_event(clnt, event))
226                         error = __rpc_clnt_handle_event(clnt, event, sb);
227                 if (error || clnt == clnt->cl_parent)
228                         break;
229         }
230         return error;
231 }
232 
233 static struct rpc_clnt *rpc_get_client_for_event(struct net *net, int event)
234 {
235         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
236         struct rpc_clnt *clnt;
237 
238         spin_lock(&sn->rpc_client_lock);
239         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
240                 if (clnt->cl_program->pipe_dir_name == NULL)
241                         continue;
242                 if (rpc_clnt_skip_event(clnt, event))
243                         continue;
244                 if (atomic_inc_not_zero(&clnt->cl_count) == 0)
245                         continue;
246                 spin_unlock(&sn->rpc_client_lock);
247                 return clnt;
248         }
249         spin_unlock(&sn->rpc_client_lock);
250         return NULL;
251 }
252 
253 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
254                             void *ptr)
255 {
256         struct super_block *sb = ptr;
257         struct rpc_clnt *clnt;
258         int error = 0;
259 
260         while ((clnt = rpc_get_client_for_event(sb->s_fs_info, event))) {
261                 error = __rpc_pipefs_event(clnt, event, sb);
262                 rpc_release_client(clnt);
263                 if (error)
264                         break;
265         }
266         return error;
267 }
268 
269 static struct notifier_block rpc_clients_block = {
270         .notifier_call  = rpc_pipefs_event,
271         .priority       = SUNRPC_PIPEFS_RPC_PRIO,
272 };
273 
274 int rpc_clients_notifier_register(void)
275 {
276         return rpc_pipefs_notifier_register(&rpc_clients_block);
277 }
278 
279 void rpc_clients_notifier_unregister(void)
280 {
281         return rpc_pipefs_notifier_unregister(&rpc_clients_block);
282 }
283 
284 static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename)
285 {
286         clnt->cl_nodelen = strlen(nodename);
287         if (clnt->cl_nodelen > UNX_MAXNODENAME)
288                 clnt->cl_nodelen = UNX_MAXNODENAME;
289         memcpy(clnt->cl_nodename, nodename, clnt->cl_nodelen);
290 }
291 
292 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
293 {
294         const struct rpc_program *program = args->program;
295         const struct rpc_version *version;
296         struct rpc_clnt         *clnt = NULL;
297         struct rpc_auth         *auth;
298         int err;
299 
300         /* sanity check the name before trying to print it */
301         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
302                         program->name, args->servername, xprt);
303 
304         err = rpciod_up();
305         if (err)
306                 goto out_no_rpciod;
307 
308         err = -EINVAL;
309         if (args->version >= program->nrvers)
310                 goto out_err;
311         version = program->version[args->version];
312         if (version == NULL)
313                 goto out_err;
314 
315         err = -ENOMEM;
316         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
317         if (!clnt)
318                 goto out_err;
319         clnt->cl_parent = clnt;
320 
321         rcu_assign_pointer(clnt->cl_xprt, xprt);
322         clnt->cl_procinfo = version->procs;
323         clnt->cl_maxproc  = version->nrprocs;
324         clnt->cl_protname = program->name;
325         clnt->cl_prog     = args->prognumber ? : program->number;
326         clnt->cl_vers     = version->number;
327         clnt->cl_stats    = program->stats;
328         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
329         err = -ENOMEM;
330         if (clnt->cl_metrics == NULL)
331                 goto out_no_stats;
332         clnt->cl_program  = program;
333         INIT_LIST_HEAD(&clnt->cl_tasks);
334         spin_lock_init(&clnt->cl_lock);
335 
336         if (!xprt_bound(xprt))
337                 clnt->cl_autobind = 1;
338 
339         clnt->cl_timeout = xprt->timeout;
340         if (args->timeout != NULL) {
341                 memcpy(&clnt->cl_timeout_default, args->timeout,
342                                 sizeof(clnt->cl_timeout_default));
343                 clnt->cl_timeout = &clnt->cl_timeout_default;
344         }
345 
346         clnt->cl_rtt = &clnt->cl_rtt_default;
347         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
348         clnt->cl_principal = NULL;
349         if (args->client_name) {
350                 clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
351                 if (!clnt->cl_principal)
352                         goto out_no_principal;
353         }
354 
355         atomic_set(&clnt->cl_count, 1);
356 
357         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
358         if (err < 0)
359                 goto out_no_path;
360 
361         auth = rpcauth_create(args->authflavor, clnt);
362         if (IS_ERR(auth)) {
363                 dprintk("RPC:       Couldn't create auth handle (flavor %u)\n",
364                                 args->authflavor);
365                 err = PTR_ERR(auth);
366                 goto out_no_auth;
367         }
368 
369         /* save the nodename */
370         rpc_clnt_set_nodename(clnt, utsname()->nodename);
371         rpc_register_client(clnt);
372         return clnt;
373 
374 out_no_auth:
375         rpc_clnt_remove_pipedir(clnt);
376 out_no_path:
377         kfree(clnt->cl_principal);
378 out_no_principal:
379         rpc_free_iostats(clnt->cl_metrics);
380 out_no_stats:
381         kfree(clnt);
382 out_err:
383         rpciod_down();
384 out_no_rpciod:
385         xprt_put(xprt);
386         return ERR_PTR(err);
387 }
388 
389 /**
390  * rpc_create - create an RPC client and transport with one call
391  * @args: rpc_clnt create argument structure
392  *
393  * Creates and initializes an RPC transport and an RPC client.
394  *
395  * It can ping the server in order to determine if it is up, and to see if
396  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
397  * this behavior so asynchronous tasks can also use rpc_create.
398  */
399 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
400 {
401         struct rpc_xprt *xprt;
402         struct rpc_clnt *clnt;
403         struct xprt_create xprtargs = {
404                 .net = args->net,
405                 .ident = args->protocol,
406                 .srcaddr = args->saddress,
407                 .dstaddr = args->address,
408                 .addrlen = args->addrsize,
409                 .servername = args->servername,
410                 .bc_xprt = args->bc_xprt,
411         };
412         char servername[48];
413 
414         if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
415                 xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
416         if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
417                 xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
418         /*
419          * If the caller chooses not to specify a hostname, whip
420          * up a string representation of the passed-in address.
421          */
422         if (xprtargs.servername == NULL) {
423                 struct sockaddr_un *sun =
424                                 (struct sockaddr_un *)args->address;
425                 struct sockaddr_in *sin =
426                                 (struct sockaddr_in *)args->address;
427                 struct sockaddr_in6 *sin6 =
428                                 (struct sockaddr_in6 *)args->address;
429 
430                 servername[0] = '\0';
431                 switch (args->address->sa_family) {
432                 case AF_LOCAL:
433                         snprintf(servername, sizeof(servername), "%s",
434                                  sun->sun_path);
435                         break;
436                 case AF_INET:
437                         snprintf(servername, sizeof(servername), "%pI4",
438                                  &sin->sin_addr.s_addr);
439                         break;
440                 case AF_INET6:
441                         snprintf(servername, sizeof(servername), "%pI6",
442                                  &sin6->sin6_addr);
443                         break;
444                 default:
445                         /* caller wants default server name, but
446                          * address family isn't recognized. */
447                         return ERR_PTR(-EINVAL);
448                 }
449                 xprtargs.servername = servername;
450         }
451 
452         xprt = xprt_create_transport(&xprtargs);
453         if (IS_ERR(xprt))
454                 return (struct rpc_clnt *)xprt;
455 
456         /*
457          * By default, kernel RPC client connects from a reserved port.
458          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
459          * but it is always enabled for rpciod, which handles the connect
460          * operation.
461          */
462         xprt->resvport = 1;
463         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
464                 xprt->resvport = 0;
465 
466         clnt = rpc_new_client(args, xprt);
467         if (IS_ERR(clnt))
468                 return clnt;
469 
470         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
471                 int err = rpc_ping(clnt);
472                 if (err != 0) {
473                         rpc_shutdown_client(clnt);
474                         return ERR_PTR(err);
475                 }
476         }
477 
478         clnt->cl_softrtry = 1;
479         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
480                 clnt->cl_softrtry = 0;
481 
482         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
483                 clnt->cl_autobind = 1;
484         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
485                 clnt->cl_discrtry = 1;
486         if (!(args->flags & RPC_CLNT_CREATE_QUIET))
487                 clnt->cl_chatty = 1;
488 
489         return clnt;
490 }
491 EXPORT_SYMBOL_GPL(rpc_create);
492 
493 /*
494  * This function clones the RPC client structure. It allows us to share the
495  * same transport while varying parameters such as the authentication
496  * flavour.
497  */
498 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
499                                            struct rpc_clnt *clnt)
500 {
501         struct rpc_xprt *xprt;
502         struct rpc_clnt *new;
503         int err;
504 
505         err = -ENOMEM;
506         rcu_read_lock();
507         xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
508         rcu_read_unlock();
509         if (xprt == NULL)
510                 goto out_err;
511         args->servername = xprt->servername;
512 
513         new = rpc_new_client(args, xprt);
514         if (IS_ERR(new)) {
515                 err = PTR_ERR(new);
516                 goto out_err;
517         }
518 
519         atomic_inc(&clnt->cl_count);
520         new->cl_parent = clnt;
521 
522         /* Turn off autobind on clones */
523         new->cl_autobind = 0;
524         new->cl_softrtry = clnt->cl_softrtry;
525         new->cl_discrtry = clnt->cl_discrtry;
526         new->cl_chatty = clnt->cl_chatty;
527         return new;
528 
529 out_err:
530         dprintk("RPC:       %s: returned error %d\n", __func__, err);
531         return ERR_PTR(err);
532 }
533 
534 /**
535  * rpc_clone_client - Clone an RPC client structure
536  *
537  * @clnt: RPC client whose parameters are copied
538  *
539  * Returns a fresh RPC client or an ERR_PTR.
540  */
541 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
542 {
543         struct rpc_create_args args = {
544                 .program        = clnt->cl_program,
545                 .prognumber     = clnt->cl_prog,
546                 .version        = clnt->cl_vers,
547                 .authflavor     = clnt->cl_auth->au_flavor,
548                 .client_name    = clnt->cl_principal,
549         };
550         return __rpc_clone_client(&args, clnt);
551 }
552 EXPORT_SYMBOL_GPL(rpc_clone_client);
553 
554 /**
555  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
556  *
557  * @clnt: RPC client whose parameters are copied
558  * @flavor: security flavor for new client
559  *
560  * Returns a fresh RPC client or an ERR_PTR.
561  */
562 struct rpc_clnt *
563 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
564 {
565         struct rpc_create_args args = {
566                 .program        = clnt->cl_program,
567                 .prognumber     = clnt->cl_prog,
568                 .version        = clnt->cl_vers,
569                 .authflavor     = flavor,
570                 .client_name    = clnt->cl_principal,
571         };
572         return __rpc_clone_client(&args, clnt);
573 }
574 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
575 
576 /*
577  * Kill all tasks for the given client.
578  * XXX: kill their descendants as well?
579  */
580 void rpc_killall_tasks(struct rpc_clnt *clnt)
581 {
582         struct rpc_task *rovr;
583 
584 
585         if (list_empty(&clnt->cl_tasks))
586                 return;
587         dprintk("RPC:       killing all tasks for client %p\n", clnt);
588         /*
589          * Spin lock all_tasks to prevent changes...
590          */
591         spin_lock(&clnt->cl_lock);
592         list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
593                 if (!RPC_IS_ACTIVATED(rovr))
594                         continue;
595                 if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
596                         rovr->tk_flags |= RPC_TASK_KILLED;
597                         rpc_exit(rovr, -EIO);
598                         if (RPC_IS_QUEUED(rovr))
599                                 rpc_wake_up_queued_task(rovr->tk_waitqueue,
600                                                         rovr);
601                 }
602         }
603         spin_unlock(&clnt->cl_lock);
604 }
605 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
606 
607 /*
608  * Properly shut down an RPC client, terminating all outstanding
609  * requests.
610  */
611 void rpc_shutdown_client(struct rpc_clnt *clnt)
612 {
613         might_sleep();
614 
615         dprintk_rcu("RPC:       shutting down %s client for %s\n",
616                         clnt->cl_protname,
617                         rcu_dereference(clnt->cl_xprt)->servername);
618 
619         while (!list_empty(&clnt->cl_tasks)) {
620                 rpc_killall_tasks(clnt);
621                 wait_event_timeout(destroy_wait,
622                         list_empty(&clnt->cl_tasks), 1*HZ);
623         }
624 
625         rpc_release_client(clnt);
626 }
627 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
628 
629 /*
630  * Free an RPC client
631  */
632 static void
633 rpc_free_client(struct rpc_clnt *clnt)
634 {
635         dprintk_rcu("RPC:       destroying %s client for %s\n",
636                         clnt->cl_protname,
637                         rcu_dereference(clnt->cl_xprt)->servername);
638         if (clnt->cl_parent != clnt)
639                 rpc_release_client(clnt->cl_parent);
640         rpc_unregister_client(clnt);
641         rpc_clnt_remove_pipedir(clnt);
642         rpc_free_iostats(clnt->cl_metrics);
643         kfree(clnt->cl_principal);
644         clnt->cl_metrics = NULL;
645         xprt_put(rcu_dereference_raw(clnt->cl_xprt));
646         rpciod_down();
647         kfree(clnt);
648 }
649 
650 /*
651  * Free an RPC client
652  */
653 static void
654 rpc_free_auth(struct rpc_clnt *clnt)
655 {
656         if (clnt->cl_auth == NULL) {
657                 rpc_free_client(clnt);
658                 return;
659         }
660 
661         /*
662          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
663          *       release remaining GSS contexts. This mechanism ensures
664          *       that it can do so safely.
665          */
666         atomic_inc(&clnt->cl_count);
667         rpcauth_release(clnt->cl_auth);
668         clnt->cl_auth = NULL;
669         if (atomic_dec_and_test(&clnt->cl_count))
670                 rpc_free_client(clnt);
671 }
672 
673 /*
674  * Release reference to the RPC client
675  */
676 void
677 rpc_release_client(struct rpc_clnt *clnt)
678 {
679         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
680 
681         if (list_empty(&clnt->cl_tasks))
682                 wake_up(&destroy_wait);
683         if (atomic_dec_and_test(&clnt->cl_count))
684                 rpc_free_auth(clnt);
685 }
686 EXPORT_SYMBOL_GPL(rpc_release_client);
687 
688 /**
689  * rpc_bind_new_program - bind a new RPC program to an existing client
690  * @old: old rpc_client
691  * @program: rpc program to set
692  * @vers: rpc program version
693  *
694  * Clones the rpc client and sets up a new RPC program. This is mainly
695  * of use for enabling different RPC programs to share the same transport.
696  * The Sun NFSv2/v3 ACL protocol can do this.
697  */
698 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
699                                       const struct rpc_program *program,
700                                       u32 vers)
701 {
702         struct rpc_create_args args = {
703                 .program        = program,
704                 .prognumber     = program->number,
705                 .version        = vers,
706                 .authflavor     = old->cl_auth->au_flavor,
707                 .client_name    = old->cl_principal,
708         };
709         struct rpc_clnt *clnt;
710         int err;
711 
712         clnt = __rpc_clone_client(&args, old);
713         if (IS_ERR(clnt))
714                 goto out;
715         err = rpc_ping(clnt);
716         if (err != 0) {
717                 rpc_shutdown_client(clnt);
718                 clnt = ERR_PTR(err);
719         }
720 out:
721         return clnt;
722 }
723 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
724 
725 void rpc_task_release_client(struct rpc_task *task)
726 {
727         struct rpc_clnt *clnt = task->tk_client;
728 
729         if (clnt != NULL) {
730                 /* Remove from client task list */
731                 spin_lock(&clnt->cl_lock);
732                 list_del(&task->tk_task);
733                 spin_unlock(&clnt->cl_lock);
734                 task->tk_client = NULL;
735 
736                 rpc_release_client(clnt);
737         }
738 }
739 
740 static
741 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
742 {
743         if (clnt != NULL) {
744                 rpc_task_release_client(task);
745                 task->tk_client = clnt;
746                 atomic_inc(&clnt->cl_count);
747                 if (clnt->cl_softrtry)
748                         task->tk_flags |= RPC_TASK_SOFT;
749                 if (sk_memalloc_socks()) {
750                         struct rpc_xprt *xprt;
751 
752                         rcu_read_lock();
753                         xprt = rcu_dereference(clnt->cl_xprt);
754                         if (xprt->swapper)
755                                 task->tk_flags |= RPC_TASK_SWAPPER;
756                         rcu_read_unlock();
757                 }
758                 /* Add to the client's list of all tasks */
759                 spin_lock(&clnt->cl_lock);
760                 list_add_tail(&task->tk_task, &clnt->cl_tasks);
761                 spin_unlock(&clnt->cl_lock);
762         }
763 }
764 
765 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
766 {
767         rpc_task_release_client(task);
768         rpc_task_set_client(task, clnt);
769 }
770 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
771 
772 
773 static void
774 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
775 {
776         if (msg != NULL) {
777                 task->tk_msg.rpc_proc = msg->rpc_proc;
778                 task->tk_msg.rpc_argp = msg->rpc_argp;
779                 task->tk_msg.rpc_resp = msg->rpc_resp;
780                 if (msg->rpc_cred != NULL)
781                         task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
782         }
783 }
784 
785 /*
786  * Default callback for async RPC calls
787  */
788 static void
789 rpc_default_callback(struct rpc_task *task, void *data)
790 {
791 }
792 
793 static const struct rpc_call_ops rpc_default_ops = {
794         .rpc_call_done = rpc_default_callback,
795 };
796 
797 /**
798  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
799  * @task_setup_data: pointer to task initialisation data
800  */
801 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
802 {
803         struct rpc_task *task;
804 
805         task = rpc_new_task(task_setup_data);
806         if (IS_ERR(task))
807                 goto out;
808 
809         rpc_task_set_client(task, task_setup_data->rpc_client);
810         rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
811 
812         if (task->tk_action == NULL)
813                 rpc_call_start(task);
814 
815         atomic_inc(&task->tk_count);
816         rpc_execute(task);
817 out:
818         return task;
819 }
820 EXPORT_SYMBOL_GPL(rpc_run_task);
821 
822 /**
823  * rpc_call_sync - Perform a synchronous RPC call
824  * @clnt: pointer to RPC client
825  * @msg: RPC call parameters
826  * @flags: RPC call flags
827  */
828 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
829 {
830         struct rpc_task *task;
831         struct rpc_task_setup task_setup_data = {
832                 .rpc_client = clnt,
833                 .rpc_message = msg,
834                 .callback_ops = &rpc_default_ops,
835                 .flags = flags,
836         };
837         int status;
838 
839         WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
840         if (flags & RPC_TASK_ASYNC) {
841                 rpc_release_calldata(task_setup_data.callback_ops,
842                         task_setup_data.callback_data);
843                 return -EINVAL;
844         }
845 
846         task = rpc_run_task(&task_setup_data);
847         if (IS_ERR(task))
848                 return PTR_ERR(task);
849         status = task->tk_status;
850         rpc_put_task(task);
851         return status;
852 }
853 EXPORT_SYMBOL_GPL(rpc_call_sync);
854 
855 /**
856  * rpc_call_async - Perform an asynchronous RPC call
857  * @clnt: pointer to RPC client
858  * @msg: RPC call parameters
859  * @flags: RPC call flags
860  * @tk_ops: RPC call ops
861  * @data: user call data
862  */
863 int
864 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
865                const struct rpc_call_ops *tk_ops, void *data)
866 {
867         struct rpc_task *task;
868         struct rpc_task_setup task_setup_data = {
869                 .rpc_client = clnt,
870                 .rpc_message = msg,
871                 .callback_ops = tk_ops,
872                 .callback_data = data,
873                 .flags = flags|RPC_TASK_ASYNC,
874         };
875 
876         task = rpc_run_task(&task_setup_data);
877         if (IS_ERR(task))
878                 return PTR_ERR(task);
879         rpc_put_task(task);
880         return 0;
881 }
882 EXPORT_SYMBOL_GPL(rpc_call_async);
883 
884 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
885 /**
886  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
887  * rpc_execute against it
888  * @req: RPC request
889  * @tk_ops: RPC call ops
890  */
891 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
892                                 const struct rpc_call_ops *tk_ops)
893 {
894         struct rpc_task *task;
895         struct xdr_buf *xbufp = &req->rq_snd_buf;
896         struct rpc_task_setup task_setup_data = {
897                 .callback_ops = tk_ops,
898         };
899 
900         dprintk("RPC: rpc_run_bc_task req= %p\n", req);
901         /*
902          * Create an rpc_task to send the data
903          */
904         task = rpc_new_task(&task_setup_data);
905         if (IS_ERR(task)) {
906                 xprt_free_bc_request(req);
907                 goto out;
908         }
909         task->tk_rqstp = req;
910 
911         /*
912          * Set up the xdr_buf length.
913          * This also indicates that the buffer is XDR encoded already.
914          */
915         xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
916                         xbufp->tail[0].iov_len;
917 
918         task->tk_action = call_bc_transmit;
919         atomic_inc(&task->tk_count);
920         WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
921         rpc_execute(task);
922 
923 out:
924         dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
925         return task;
926 }
927 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
928 
929 void
930 rpc_call_start(struct rpc_task *task)
931 {
932         task->tk_action = call_start;
933 }
934 EXPORT_SYMBOL_GPL(rpc_call_start);
935 
936 /**
937  * rpc_peeraddr - extract remote peer address from clnt's xprt
938  * @clnt: RPC client structure
939  * @buf: target buffer
940  * @bufsize: length of target buffer
941  *
942  * Returns the number of bytes that are actually in the stored address.
943  */
944 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
945 {
946         size_t bytes;
947         struct rpc_xprt *xprt;
948 
949         rcu_read_lock();
950         xprt = rcu_dereference(clnt->cl_xprt);
951 
952         bytes = xprt->addrlen;
953         if (bytes > bufsize)
954                 bytes = bufsize;
955         memcpy(buf, &xprt->addr, bytes);
956         rcu_read_unlock();
957 
958         return bytes;
959 }
960 EXPORT_SYMBOL_GPL(rpc_peeraddr);
961 
962 /**
963  * rpc_peeraddr2str - return remote peer address in printable format
964  * @clnt: RPC client structure
965  * @format: address format
966  *
967  * NB: the lifetime of the memory referenced by the returned pointer is
968  * the same as the rpc_xprt itself.  As long as the caller uses this
969  * pointer, it must hold the RCU read lock.
970  */
971 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
972                              enum rpc_display_format_t format)
973 {
974         struct rpc_xprt *xprt;
975 
976         xprt = rcu_dereference(clnt->cl_xprt);
977 
978         if (xprt->address_strings[format] != NULL)
979                 return xprt->address_strings[format];
980         else
981                 return "unprintable";
982 }
983 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
984 
985 static const struct sockaddr_in rpc_inaddr_loopback = {
986         .sin_family             = AF_INET,
987         .sin_addr.s_addr        = htonl(INADDR_ANY),
988 };
989 
990 static const struct sockaddr_in6 rpc_in6addr_loopback = {
991         .sin6_family            = AF_INET6,
992         .sin6_addr              = IN6ADDR_ANY_INIT,
993 };
994 
995 /*
996  * Try a getsockname() on a connected datagram socket.  Using a
997  * connected datagram socket prevents leaving a socket in TIME_WAIT.
998  * This conserves the ephemeral port number space.
999  *
1000  * Returns zero and fills in "buf" if successful; otherwise, a
1001  * negative errno is returned.
1002  */
1003 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1004                         struct sockaddr *buf, int buflen)
1005 {
1006         struct socket *sock;
1007         int err;
1008 
1009         err = __sock_create(net, sap->sa_family,
1010                                 SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1011         if (err < 0) {
1012                 dprintk("RPC:       can't create UDP socket (%d)\n", err);
1013                 goto out;
1014         }
1015 
1016         switch (sap->sa_family) {
1017         case AF_INET:
1018                 err = kernel_bind(sock,
1019                                 (struct sockaddr *)&rpc_inaddr_loopback,
1020                                 sizeof(rpc_inaddr_loopback));
1021                 break;
1022         case AF_INET6:
1023                 err = kernel_bind(sock,
1024                                 (struct sockaddr *)&rpc_in6addr_loopback,
1025                                 sizeof(rpc_in6addr_loopback));
1026                 break;
1027         default:
1028                 err = -EAFNOSUPPORT;
1029                 goto out;
1030         }
1031         if (err < 0) {
1032                 dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1033                 goto out_release;
1034         }
1035 
1036         err = kernel_connect(sock, sap, salen, 0);
1037         if (err < 0) {
1038                 dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1039                 goto out_release;
1040         }
1041 
1042         err = kernel_getsockname(sock, buf, &buflen);
1043         if (err < 0) {
1044                 dprintk("RPC:       getsockname failed (%d)\n", err);
1045                 goto out_release;
1046         }
1047 
1048         err = 0;
1049         if (buf->sa_family == AF_INET6) {
1050                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1051                 sin6->sin6_scope_id = 0;
1052         }
1053         dprintk("RPC:       %s succeeded\n", __func__);
1054 
1055 out_release:
1056         sock_release(sock);
1057 out:
1058         return err;
1059 }
1060 
1061 /*
1062  * Scraping a connected socket failed, so we don't have a useable
1063  * local address.  Fallback: generate an address that will prevent
1064  * the server from calling us back.
1065  *
1066  * Returns zero and fills in "buf" if successful; otherwise, a
1067  * negative errno is returned.
1068  */
1069 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1070 {
1071         switch (family) {
1072         case AF_INET:
1073                 if (buflen < sizeof(rpc_inaddr_loopback))
1074                         return -EINVAL;
1075                 memcpy(buf, &rpc_inaddr_loopback,
1076                                 sizeof(rpc_inaddr_loopback));
1077                 break;
1078         case AF_INET6:
1079                 if (buflen < sizeof(rpc_in6addr_loopback))
1080                         return -EINVAL;
1081                 memcpy(buf, &rpc_in6addr_loopback,
1082                                 sizeof(rpc_in6addr_loopback));
1083         default:
1084                 dprintk("RPC:       %s: address family not supported\n",
1085                         __func__);
1086                 return -EAFNOSUPPORT;
1087         }
1088         dprintk("RPC:       %s: succeeded\n", __func__);
1089         return 0;
1090 }
1091 
1092 /**
1093  * rpc_localaddr - discover local endpoint address for an RPC client
1094  * @clnt: RPC client structure
1095  * @buf: target buffer
1096  * @buflen: size of target buffer, in bytes
1097  *
1098  * Returns zero and fills in "buf" and "buflen" if successful;
1099  * otherwise, a negative errno is returned.
1100  *
1101  * This works even if the underlying transport is not currently connected,
1102  * or if the upper layer never previously provided a source address.
1103  *
1104  * The result of this function call is transient: multiple calls in
1105  * succession may give different results, depending on how local
1106  * networking configuration changes over time.
1107  */
1108 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1109 {
1110         struct sockaddr_storage address;
1111         struct sockaddr *sap = (struct sockaddr *)&address;
1112         struct rpc_xprt *xprt;
1113         struct net *net;
1114         size_t salen;
1115         int err;
1116 
1117         rcu_read_lock();
1118         xprt = rcu_dereference(clnt->cl_xprt);
1119         salen = xprt->addrlen;
1120         memcpy(sap, &xprt->addr, salen);
1121         net = get_net(xprt->xprt_net);
1122         rcu_read_unlock();
1123 
1124         rpc_set_port(sap, 0);
1125         err = rpc_sockname(net, sap, salen, buf, buflen);
1126         put_net(net);
1127         if (err != 0)
1128                 /* Couldn't discover local address, return ANYADDR */
1129                 return rpc_anyaddr(sap->sa_family, buf, buflen);
1130         return 0;
1131 }
1132 EXPORT_SYMBOL_GPL(rpc_localaddr);
1133 
1134 void
1135 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1136 {
1137         struct rpc_xprt *xprt;
1138 
1139         rcu_read_lock();
1140         xprt = rcu_dereference(clnt->cl_xprt);
1141         if (xprt->ops->set_buffer_size)
1142                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1143         rcu_read_unlock();
1144 }
1145 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1146 
1147 /**
1148  * rpc_protocol - Get transport protocol number for an RPC client
1149  * @clnt: RPC client to query
1150  *
1151  */
1152 int rpc_protocol(struct rpc_clnt *clnt)
1153 {
1154         int protocol;
1155 
1156         rcu_read_lock();
1157         protocol = rcu_dereference(clnt->cl_xprt)->prot;
1158         rcu_read_unlock();
1159         return protocol;
1160 }
1161 EXPORT_SYMBOL_GPL(rpc_protocol);
1162 
1163 /**
1164  * rpc_net_ns - Get the network namespace for this RPC client
1165  * @clnt: RPC client to query
1166  *
1167  */
1168 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1169 {
1170         struct net *ret;
1171 
1172         rcu_read_lock();
1173         ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1174         rcu_read_unlock();
1175         return ret;
1176 }
1177 EXPORT_SYMBOL_GPL(rpc_net_ns);
1178 
1179 /**
1180  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1181  * @clnt: RPC client to query
1182  *
1183  * For stream transports, this is one RPC record fragment (see RFC
1184  * 1831), as we don't support multi-record requests yet.  For datagram
1185  * transports, this is the size of an IP packet minus the IP, UDP, and
1186  * RPC header sizes.
1187  */
1188 size_t rpc_max_payload(struct rpc_clnt *clnt)
1189 {
1190         size_t ret;
1191 
1192         rcu_read_lock();
1193         ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1194         rcu_read_unlock();
1195         return ret;
1196 }
1197 EXPORT_SYMBOL_GPL(rpc_max_payload);
1198 
1199 /**
1200  * rpc_get_timeout - Get timeout for transport in units of HZ
1201  * @clnt: RPC client to query
1202  */
1203 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1204 {
1205         unsigned long ret;
1206 
1207         rcu_read_lock();
1208         ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1209         rcu_read_unlock();
1210         return ret;
1211 }
1212 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1213 
1214 /**
1215  * rpc_force_rebind - force transport to check that remote port is unchanged
1216  * @clnt: client to rebind
1217  *
1218  */
1219 void rpc_force_rebind(struct rpc_clnt *clnt)
1220 {
1221         if (clnt->cl_autobind) {
1222                 rcu_read_lock();
1223                 xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1224                 rcu_read_unlock();
1225         }
1226 }
1227 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1228 
1229 /*
1230  * Restart an (async) RPC call from the call_prepare state.
1231  * Usually called from within the exit handler.
1232  */
1233 int
1234 rpc_restart_call_prepare(struct rpc_task *task)
1235 {
1236         if (RPC_ASSASSINATED(task))
1237                 return 0;
1238         task->tk_action = call_start;
1239         if (task->tk_ops->rpc_call_prepare != NULL)
1240                 task->tk_action = rpc_prepare_task;
1241         return 1;
1242 }
1243 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1244 
1245 /*
1246  * Restart an (async) RPC call. Usually called from within the
1247  * exit handler.
1248  */
1249 int
1250 rpc_restart_call(struct rpc_task *task)
1251 {
1252         if (RPC_ASSASSINATED(task))
1253                 return 0;
1254         task->tk_action = call_start;
1255         return 1;
1256 }
1257 EXPORT_SYMBOL_GPL(rpc_restart_call);
1258 
1259 #ifdef RPC_DEBUG
1260 static const char *rpc_proc_name(const struct rpc_task *task)
1261 {
1262         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1263 
1264         if (proc) {
1265                 if (proc->p_name)
1266                         return proc->p_name;
1267                 else
1268                         return "NULL";
1269         } else
1270                 return "no proc";
1271 }
1272 #endif
1273 
1274 /*
1275  * 0.  Initial state
1276  *
1277  *     Other FSM states can be visited zero or more times, but
1278  *     this state is visited exactly once for each RPC.
1279  */
1280 static void
1281 call_start(struct rpc_task *task)
1282 {
1283         struct rpc_clnt *clnt = task->tk_client;
1284 
1285         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1286                         clnt->cl_protname, clnt->cl_vers,
1287                         rpc_proc_name(task),
1288                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
1289 
1290         /* Increment call count */
1291         task->tk_msg.rpc_proc->p_count++;
1292         clnt->cl_stats->rpccnt++;
1293         task->tk_action = call_reserve;
1294 }
1295 
1296 /*
1297  * 1.   Reserve an RPC call slot
1298  */
1299 static void
1300 call_reserve(struct rpc_task *task)
1301 {
1302         dprint_status(task);
1303 
1304         task->tk_status  = 0;
1305         task->tk_action  = call_reserveresult;
1306         xprt_reserve(task);
1307 }
1308 
1309 static void call_retry_reserve(struct rpc_task *task);
1310 
1311 /*
1312  * 1b.  Grok the result of xprt_reserve()
1313  */
1314 static void
1315 call_reserveresult(struct rpc_task *task)
1316 {
1317         int status = task->tk_status;
1318 
1319         dprint_status(task);
1320 
1321         /*
1322          * After a call to xprt_reserve(), we must have either
1323          * a request slot or else an error status.
1324          */
1325         task->tk_status = 0;
1326         if (status >= 0) {
1327                 if (task->tk_rqstp) {
1328                         task->tk_action = call_refresh;
1329                         return;
1330                 }
1331 
1332                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1333                                 __func__, status);
1334                 rpc_exit(task, -EIO);
1335                 return;
1336         }
1337 
1338         /*
1339          * Even though there was an error, we may have acquired
1340          * a request slot somehow.  Make sure not to leak it.
1341          */
1342         if (task->tk_rqstp) {
1343                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1344                                 __func__, status);
1345                 xprt_release(task);
1346         }
1347 
1348         switch (status) {
1349         case -ENOMEM:
1350                 rpc_delay(task, HZ >> 2);
1351         case -EAGAIN:   /* woken up; retry */
1352                 task->tk_action = call_retry_reserve;
1353                 return;
1354         case -EIO:      /* probably a shutdown */
1355                 break;
1356         default:
1357                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1358                                 __func__, status);
1359                 break;
1360         }
1361         rpc_exit(task, status);
1362 }
1363 
1364 /*
1365  * 1c.  Retry reserving an RPC call slot
1366  */
1367 static void
1368 call_retry_reserve(struct rpc_task *task)
1369 {
1370         dprint_status(task);
1371 
1372         task->tk_status  = 0;
1373         task->tk_action  = call_reserveresult;
1374         xprt_retry_reserve(task);
1375 }
1376 
1377 /*
1378  * 2.   Bind and/or refresh the credentials
1379  */
1380 static void
1381 call_refresh(struct rpc_task *task)
1382 {
1383         dprint_status(task);
1384 
1385         task->tk_action = call_refreshresult;
1386         task->tk_status = 0;
1387         task->tk_client->cl_stats->rpcauthrefresh++;
1388         rpcauth_refreshcred(task);
1389 }
1390 
1391 /*
1392  * 2a.  Process the results of a credential refresh
1393  */
1394 static void
1395 call_refreshresult(struct rpc_task *task)
1396 {
1397         int status = task->tk_status;
1398 
1399         dprint_status(task);
1400 
1401         task->tk_status = 0;
1402         task->tk_action = call_refresh;
1403         switch (status) {
1404         case 0:
1405                 if (rpcauth_uptodatecred(task)) {
1406                         task->tk_action = call_allocate;
1407                         return;
1408                 }
1409                 /* Use rate-limiting and a max number of retries if refresh
1410                  * had status 0 but failed to update the cred.
1411                  */
1412         case -ETIMEDOUT:
1413                 rpc_delay(task, 3*HZ);
1414         case -EAGAIN:
1415                 status = -EACCES;
1416         case -EKEYEXPIRED:
1417                 if (!task->tk_cred_retry)
1418                         break;
1419                 task->tk_cred_retry--;
1420                 dprintk("RPC: %5u %s: retry refresh creds\n",
1421                                 task->tk_pid, __func__);
1422                 return;
1423         }
1424         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1425                                 task->tk_pid, __func__, status);
1426         rpc_exit(task, status);
1427 }
1428 
1429 /*
1430  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1431  *      (Note: buffer memory is freed in xprt_release).
1432  */
1433 static void
1434 call_allocate(struct rpc_task *task)
1435 {
1436         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1437         struct rpc_rqst *req = task->tk_rqstp;
1438         struct rpc_xprt *xprt = req->rq_xprt;
1439         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1440 
1441         dprint_status(task);
1442 
1443         task->tk_status = 0;
1444         task->tk_action = call_bind;
1445 
1446         if (req->rq_buffer)
1447                 return;
1448 
1449         if (proc->p_proc != 0) {
1450                 BUG_ON(proc->p_arglen == 0);
1451                 if (proc->p_decode != NULL)
1452                         BUG_ON(proc->p_replen == 0);
1453         }
1454 
1455         /*
1456          * Calculate the size (in quads) of the RPC call
1457          * and reply headers, and convert both values
1458          * to byte sizes.
1459          */
1460         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1461         req->rq_callsize <<= 2;
1462         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1463         req->rq_rcvsize <<= 2;
1464 
1465         req->rq_buffer = xprt->ops->buf_alloc(task,
1466                                         req->rq_callsize + req->rq_rcvsize);
1467         if (req->rq_buffer != NULL)
1468                 return;
1469 
1470         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1471 
1472         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1473                 task->tk_action = call_allocate;
1474                 rpc_delay(task, HZ>>4);
1475                 return;
1476         }
1477 
1478         rpc_exit(task, -ERESTARTSYS);
1479 }
1480 
1481 static inline int
1482 rpc_task_need_encode(struct rpc_task *task)
1483 {
1484         return task->tk_rqstp->rq_snd_buf.len == 0;
1485 }
1486 
1487 static inline void
1488 rpc_task_force_reencode(struct rpc_task *task)
1489 {
1490         task->tk_rqstp->rq_snd_buf.len = 0;
1491         task->tk_rqstp->rq_bytes_sent = 0;
1492 }
1493 
1494 static inline void
1495 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1496 {
1497         buf->head[0].iov_base = start;
1498         buf->head[0].iov_len = len;
1499         buf->tail[0].iov_len = 0;
1500         buf->page_len = 0;
1501         buf->flags = 0;
1502         buf->len = 0;
1503         buf->buflen = len;
1504 }
1505 
1506 /*
1507  * 3.   Encode arguments of an RPC call
1508  */
1509 static void
1510 rpc_xdr_encode(struct rpc_task *task)
1511 {
1512         struct rpc_rqst *req = task->tk_rqstp;
1513         kxdreproc_t     encode;
1514         __be32          *p;
1515 
1516         dprint_status(task);
1517 
1518         rpc_xdr_buf_init(&req->rq_snd_buf,
1519                          req->rq_buffer,
1520                          req->rq_callsize);
1521         rpc_xdr_buf_init(&req->rq_rcv_buf,
1522                          (char *)req->rq_buffer + req->rq_callsize,
1523                          req->rq_rcvsize);
1524 
1525         p = rpc_encode_header(task);
1526         if (p == NULL) {
1527                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1528                 rpc_exit(task, -EIO);
1529                 return;
1530         }
1531 
1532         encode = task->tk_msg.rpc_proc->p_encode;
1533         if (encode == NULL)
1534                 return;
1535 
1536         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1537                         task->tk_msg.rpc_argp);
1538 }
1539 
1540 /*
1541  * 4.   Get the server port number if not yet set
1542  */
1543 static void
1544 call_bind(struct rpc_task *task)
1545 {
1546         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1547 
1548         dprint_status(task);
1549 
1550         task->tk_action = call_connect;
1551         if (!xprt_bound(xprt)) {
1552                 task->tk_action = call_bind_status;
1553                 task->tk_timeout = xprt->bind_timeout;
1554                 xprt->ops->rpcbind(task);
1555         }
1556 }
1557 
1558 /*
1559  * 4a.  Sort out bind result
1560  */
1561 static void
1562 call_bind_status(struct rpc_task *task)
1563 {
1564         int status = -EIO;
1565 
1566         if (task->tk_status >= 0) {
1567                 dprint_status(task);
1568                 task->tk_status = 0;
1569                 task->tk_action = call_connect;
1570                 return;
1571         }
1572 
1573         trace_rpc_bind_status(task);
1574         switch (task->tk_status) {
1575         case -ENOMEM:
1576                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1577                 rpc_delay(task, HZ >> 2);
1578                 goto retry_timeout;
1579         case -EACCES:
1580                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1581                                 "unavailable\n", task->tk_pid);
1582                 /* fail immediately if this is an RPC ping */
1583                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1584                         status = -EOPNOTSUPP;
1585                         break;
1586                 }
1587                 if (task->tk_rebind_retry == 0)
1588                         break;
1589                 task->tk_rebind_retry--;
1590                 rpc_delay(task, 3*HZ);
1591                 goto retry_timeout;
1592         case -ETIMEDOUT:
1593                 dprintk("RPC: %5u rpcbind request timed out\n",
1594                                 task->tk_pid);
1595                 goto retry_timeout;
1596         case -EPFNOSUPPORT:
1597                 /* server doesn't support any rpcbind version we know of */
1598                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1599                                 task->tk_pid);
1600                 break;
1601         case -EPROTONOSUPPORT:
1602                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1603                                 task->tk_pid);
1604                 task->tk_status = 0;
1605                 task->tk_action = call_bind;
1606                 return;
1607         case -ECONNREFUSED:             /* connection problems */
1608         case -ECONNRESET:
1609         case -ENOTCONN:
1610         case -EHOSTDOWN:
1611         case -EHOSTUNREACH:
1612         case -ENETUNREACH:
1613         case -EPIPE:
1614                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1615                                 task->tk_pid, task->tk_status);
1616                 if (!RPC_IS_SOFTCONN(task)) {
1617                         rpc_delay(task, 5*HZ);
1618                         goto retry_timeout;
1619                 }
1620                 status = task->tk_status;
1621                 break;
1622         default:
1623                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1624                                 task->tk_pid, -task->tk_status);
1625         }
1626 
1627         rpc_exit(task, status);
1628         return;
1629 
1630 retry_timeout:
1631         task->tk_action = call_timeout;
1632 }
1633 
1634 /*
1635  * 4b.  Connect to the RPC server
1636  */
1637 static void
1638 call_connect(struct rpc_task *task)
1639 {
1640         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1641 
1642         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1643                         task->tk_pid, xprt,
1644                         (xprt_connected(xprt) ? "is" : "is not"));
1645 
1646         task->tk_action = call_transmit;
1647         if (!xprt_connected(xprt)) {
1648                 task->tk_action = call_connect_status;
1649                 if (task->tk_status < 0)
1650                         return;
1651                 if (task->tk_flags & RPC_TASK_NOCONNECT) {
1652                         rpc_exit(task, -ENOTCONN);
1653                         return;
1654                 }
1655                 xprt_connect(task);
1656         }
1657 }
1658 
1659 /*
1660  * 4c.  Sort out connect result
1661  */
1662 static void
1663 call_connect_status(struct rpc_task *task)
1664 {
1665         struct rpc_clnt *clnt = task->tk_client;
1666         int status = task->tk_status;
1667 
1668         dprint_status(task);
1669 
1670         trace_rpc_connect_status(task, status);
1671         switch (status) {
1672                 /* if soft mounted, test if we've timed out */
1673         case -ETIMEDOUT:
1674                 task->tk_action = call_timeout;
1675                 return;
1676         case -ECONNREFUSED:
1677         case -ECONNRESET:
1678         case -ENETUNREACH:
1679                 if (RPC_IS_SOFTCONN(task))
1680                         break;
1681                 /* retry with existing socket, after a delay */
1682         case 0:
1683         case -EAGAIN:
1684                 task->tk_status = 0;
1685                 clnt->cl_stats->netreconn++;
1686                 task->tk_action = call_transmit;
1687                 return;
1688         }
1689         rpc_exit(task, status);
1690 }
1691 
1692 /*
1693  * 5.   Transmit the RPC request, and wait for reply
1694  */
1695 static void
1696 call_transmit(struct rpc_task *task)
1697 {
1698         dprint_status(task);
1699 
1700         task->tk_action = call_status;
1701         if (task->tk_status < 0)
1702                 return;
1703         task->tk_status = xprt_prepare_transmit(task);
1704         if (task->tk_status != 0)
1705                 return;
1706         task->tk_action = call_transmit_status;
1707         /* Encode here so that rpcsec_gss can use correct sequence number. */
1708         if (rpc_task_need_encode(task)) {
1709                 rpc_xdr_encode(task);
1710                 /* Did the encode result in an error condition? */
1711                 if (task->tk_status != 0) {
1712                         /* Was the error nonfatal? */
1713                         if (task->tk_status == -EAGAIN)
1714                                 rpc_delay(task, HZ >> 4);
1715                         else
1716                                 rpc_exit(task, task->tk_status);
1717                         return;
1718                 }
1719         }
1720         xprt_transmit(task);
1721         if (task->tk_status < 0)
1722                 return;
1723         /*
1724          * On success, ensure that we call xprt_end_transmit() before sleeping
1725          * in order to allow access to the socket to other RPC requests.
1726          */
1727         call_transmit_status(task);
1728         if (rpc_reply_expected(task))
1729                 return;
1730         task->tk_action = rpc_exit_task;
1731         rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1732 }
1733 
1734 /*
1735  * 5a.  Handle cleanup after a transmission
1736  */
1737 static void
1738 call_transmit_status(struct rpc_task *task)
1739 {
1740         task->tk_action = call_status;
1741 
1742         /*
1743          * Common case: success.  Force the compiler to put this
1744          * test first.
1745          */
1746         if (task->tk_status == 0) {
1747                 xprt_end_transmit(task);
1748                 rpc_task_force_reencode(task);
1749                 return;
1750         }
1751 
1752         switch (task->tk_status) {
1753         case -EAGAIN:
1754                 break;
1755         default:
1756                 dprint_status(task);
1757                 xprt_end_transmit(task);
1758                 rpc_task_force_reencode(task);
1759                 break;
1760                 /*
1761                  * Special cases: if we've been waiting on the
1762                  * socket's write_space() callback, or if the
1763                  * socket just returned a connection error,
1764                  * then hold onto the transport lock.
1765                  */
1766         case -ECONNREFUSED:
1767         case -EHOSTDOWN:
1768         case -EHOSTUNREACH:
1769         case -ENETUNREACH:
1770                 if (RPC_IS_SOFTCONN(task)) {
1771                         xprt_end_transmit(task);
1772                         rpc_exit(task, task->tk_status);
1773                         break;
1774                 }
1775         case -ECONNRESET:
1776         case -ENOTCONN:
1777         case -EPIPE:
1778                 rpc_task_force_reencode(task);
1779         }
1780 }
1781 
1782 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1783 /*
1784  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
1785  * addition, disconnect on connectivity errors.
1786  */
1787 static void
1788 call_bc_transmit(struct rpc_task *task)
1789 {
1790         struct rpc_rqst *req = task->tk_rqstp;
1791 
1792         task->tk_status = xprt_prepare_transmit(task);
1793         if (task->tk_status == -EAGAIN) {
1794                 /*
1795                  * Could not reserve the transport. Try again after the
1796                  * transport is released.
1797                  */
1798                 task->tk_status = 0;
1799                 task->tk_action = call_bc_transmit;
1800                 return;
1801         }
1802 
1803         task->tk_action = rpc_exit_task;
1804         if (task->tk_status < 0) {
1805                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1806                         "error: %d\n", task->tk_status);
1807                 return;
1808         }
1809 
1810         xprt_transmit(task);
1811         xprt_end_transmit(task);
1812         dprint_status(task);
1813         switch (task->tk_status) {
1814         case 0:
1815                 /* Success */
1816                 break;
1817         case -EHOSTDOWN:
1818         case -EHOSTUNREACH:
1819         case -ENETUNREACH:
1820         case -ETIMEDOUT:
1821                 /*
1822                  * Problem reaching the server.  Disconnect and let the
1823                  * forechannel reestablish the connection.  The server will
1824                  * have to retransmit the backchannel request and we'll
1825                  * reprocess it.  Since these ops are idempotent, there's no
1826                  * need to cache our reply at this time.
1827                  */
1828                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1829                         "error: %d\n", task->tk_status);
1830                 xprt_conditional_disconnect(req->rq_xprt,
1831                         req->rq_connect_cookie);
1832                 break;
1833         default:
1834                 /*
1835                  * We were unable to reply and will have to drop the
1836                  * request.  The server should reconnect and retransmit.
1837                  */
1838                 WARN_ON_ONCE(task->tk_status == -EAGAIN);
1839                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1840                         "error: %d\n", task->tk_status);
1841                 break;
1842         }
1843         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1844 }
1845 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1846 
1847 /*
1848  * 6.   Sort out the RPC call status
1849  */
1850 static void
1851 call_status(struct rpc_task *task)
1852 {
1853         struct rpc_clnt *clnt = task->tk_client;
1854         struct rpc_rqst *req = task->tk_rqstp;
1855         int             status;
1856 
1857         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
1858                 task->tk_status = req->rq_reply_bytes_recvd;
1859 
1860         dprint_status(task);
1861 
1862         status = task->tk_status;
1863         if (status >= 0) {
1864                 task->tk_action = call_decode;
1865                 return;
1866         }
1867 
1868         trace_rpc_call_status(task);
1869         task->tk_status = 0;
1870         switch(status) {
1871         case -EHOSTDOWN:
1872         case -EHOSTUNREACH:
1873         case -ENETUNREACH:
1874                 /*
1875                  * Delay any retries for 3 seconds, then handle as if it
1876                  * were a timeout.
1877                  */
1878                 rpc_delay(task, 3*HZ);
1879         case -ETIMEDOUT:
1880                 task->tk_action = call_timeout;
1881                 if (task->tk_client->cl_discrtry)
1882                         xprt_conditional_disconnect(req->rq_xprt,
1883                                         req->rq_connect_cookie);
1884                 break;
1885         case -ECONNRESET:
1886         case -ECONNREFUSED:
1887                 rpc_force_rebind(clnt);
1888                 rpc_delay(task, 3*HZ);
1889         case -EPIPE:
1890         case -ENOTCONN:
1891                 task->tk_action = call_bind;
1892                 break;
1893         case -EAGAIN:
1894                 task->tk_action = call_transmit;
1895                 break;
1896         case -EIO:
1897                 /* shutdown or soft timeout */
1898                 rpc_exit(task, status);
1899                 break;
1900         default:
1901                 if (clnt->cl_chatty)
1902                         printk("%s: RPC call returned error %d\n",
1903                                clnt->cl_protname, -status);
1904                 rpc_exit(task, status);
1905         }
1906 }
1907 
1908 /*
1909  * 6a.  Handle RPC timeout
1910  *      We do not release the request slot, so we keep using the
1911  *      same XID for all retransmits.
1912  */
1913 static void
1914 call_timeout(struct rpc_task *task)
1915 {
1916         struct rpc_clnt *clnt = task->tk_client;
1917 
1918         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1919                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1920                 goto retry;
1921         }
1922 
1923         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1924         task->tk_timeouts++;
1925 
1926         if (RPC_IS_SOFTCONN(task)) {
1927                 rpc_exit(task, -ETIMEDOUT);
1928                 return;
1929         }
1930         if (RPC_IS_SOFT(task)) {
1931                 if (clnt->cl_chatty) {
1932                         rcu_read_lock();
1933                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1934                                 clnt->cl_protname,
1935                                 rcu_dereference(clnt->cl_xprt)->servername);
1936                         rcu_read_unlock();
1937                 }
1938                 if (task->tk_flags & RPC_TASK_TIMEOUT)
1939                         rpc_exit(task, -ETIMEDOUT);
1940                 else
1941                         rpc_exit(task, -EIO);
1942                 return;
1943         }
1944 
1945         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1946                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1947                 if (clnt->cl_chatty) {
1948                         rcu_read_lock();
1949                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1950                         clnt->cl_protname,
1951                         rcu_dereference(clnt->cl_xprt)->servername);
1952                         rcu_read_unlock();
1953                 }
1954         }
1955         rpc_force_rebind(clnt);
1956         /*
1957          * Did our request time out due to an RPCSEC_GSS out-of-sequence
1958          * event? RFC2203 requires the server to drop all such requests.
1959          */
1960         rpcauth_invalcred(task);
1961 
1962 retry:
1963         clnt->cl_stats->rpcretrans++;
1964         task->tk_action = call_bind;
1965         task->tk_status = 0;
1966 }
1967 
1968 /*
1969  * 7.   Decode the RPC reply
1970  */
1971 static void
1972 call_decode(struct rpc_task *task)
1973 {
1974         struct rpc_clnt *clnt = task->tk_client;
1975         struct rpc_rqst *req = task->tk_rqstp;
1976         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
1977         __be32          *p;
1978 
1979         dprint_status(task);
1980 
1981         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1982                 if (clnt->cl_chatty) {
1983                         rcu_read_lock();
1984                         printk(KERN_NOTICE "%s: server %s OK\n",
1985                                 clnt->cl_protname,
1986                                 rcu_dereference(clnt->cl_xprt)->servername);
1987                         rcu_read_unlock();
1988                 }
1989                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1990         }
1991 
1992         /*
1993          * Ensure that we see all writes made by xprt_complete_rqst()
1994          * before it changed req->rq_reply_bytes_recvd.
1995          */
1996         smp_rmb();
1997         req->rq_rcv_buf.len = req->rq_private_buf.len;
1998 
1999         /* Check that the softirq receive buffer is valid */
2000         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
2001                                 sizeof(req->rq_rcv_buf)) != 0);
2002 
2003         if (req->rq_rcv_buf.len < 12) {
2004                 if (!RPC_IS_SOFT(task)) {
2005                         task->tk_action = call_bind;
2006                         clnt->cl_stats->rpcretrans++;
2007                         goto out_retry;
2008                 }
2009                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2010                                 clnt->cl_protname, task->tk_status);
2011                 task->tk_action = call_timeout;
2012                 goto out_retry;
2013         }
2014 
2015         p = rpc_verify_header(task);
2016         if (IS_ERR(p)) {
2017                 if (p == ERR_PTR(-EAGAIN))
2018                         goto out_retry;
2019                 return;
2020         }
2021 
2022         task->tk_action = rpc_exit_task;
2023 
2024         if (decode) {
2025                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2026                                                       task->tk_msg.rpc_resp);
2027         }
2028         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2029                         task->tk_status);
2030         return;
2031 out_retry:
2032         task->tk_status = 0;
2033         /* Note: rpc_verify_header() may have freed the RPC slot */
2034         if (task->tk_rqstp == req) {
2035                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2036                 if (task->tk_client->cl_discrtry)
2037                         xprt_conditional_disconnect(req->rq_xprt,
2038                                         req->rq_connect_cookie);
2039         }
2040 }
2041 
2042 static __be32 *
2043 rpc_encode_header(struct rpc_task *task)
2044 {
2045         struct rpc_clnt *clnt = task->tk_client;
2046         struct rpc_rqst *req = task->tk_rqstp;
2047         __be32          *p = req->rq_svec[0].iov_base;
2048 
2049         /* FIXME: check buffer size? */
2050 
2051         p = xprt_skip_transport_header(req->rq_xprt, p);
2052         *p++ = req->rq_xid;             /* XID */
2053         *p++ = htonl(RPC_CALL);         /* CALL */
2054         *p++ = htonl(RPC_VERSION);      /* RPC version */
2055         *p++ = htonl(clnt->cl_prog);    /* program number */
2056         *p++ = htonl(clnt->cl_vers);    /* program version */
2057         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
2058         p = rpcauth_marshcred(task, p);
2059         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2060         return p;
2061 }
2062 
2063 static __be32 *
2064 rpc_verify_header(struct rpc_task *task)
2065 {
2066         struct rpc_clnt *clnt = task->tk_client;
2067         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2068         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2069         __be32  *p = iov->iov_base;
2070         u32 n;
2071         int error = -EACCES;
2072 
2073         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2074                 /* RFC-1014 says that the representation of XDR data must be a
2075                  * multiple of four bytes
2076                  * - if it isn't pointer subtraction in the NFS client may give
2077                  *   undefined results
2078                  */
2079                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
2080                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2081                        task->tk_rqstp->rq_rcv_buf.len);
2082                 goto out_eio;
2083         }
2084         if ((len -= 3) < 0)
2085                 goto out_overflow;
2086 
2087         p += 1; /* skip XID */
2088         if ((n = ntohl(*p++)) != RPC_REPLY) {
2089                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2090                         task->tk_pid, __func__, n);
2091                 goto out_garbage;
2092         }
2093 
2094         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2095                 if (--len < 0)
2096                         goto out_overflow;
2097                 switch ((n = ntohl(*p++))) {
2098                 case RPC_AUTH_ERROR:
2099                         break;
2100                 case RPC_MISMATCH:
2101                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2102                                 task->tk_pid, __func__);
2103                         error = -EPROTONOSUPPORT;
2104                         goto out_err;
2105                 default:
2106                         dprintk("RPC: %5u %s: RPC call rejected, "
2107                                 "unknown error: %x\n",
2108                                 task->tk_pid, __func__, n);
2109                         goto out_eio;
2110                 }
2111                 if (--len < 0)
2112                         goto out_overflow;
2113                 switch ((n = ntohl(*p++))) {
2114                 case RPC_AUTH_REJECTEDCRED:
2115                 case RPC_AUTH_REJECTEDVERF:
2116                 case RPCSEC_GSS_CREDPROBLEM:
2117                 case RPCSEC_GSS_CTXPROBLEM:
2118                         if (!task->tk_cred_retry)
2119                                 break;
2120                         task->tk_cred_retry--;
2121                         dprintk("RPC: %5u %s: retry stale creds\n",
2122                                         task->tk_pid, __func__);
2123                         rpcauth_invalcred(task);
2124                         /* Ensure we obtain a new XID! */
2125                         xprt_release(task);
2126                         task->tk_action = call_reserve;
2127                         goto out_retry;
2128                 case RPC_AUTH_BADCRED:
2129                 case RPC_AUTH_BADVERF:
2130                         /* possibly garbled cred/verf? */
2131                         if (!task->tk_garb_retry)
2132                                 break;
2133                         task->tk_garb_retry--;
2134                         dprintk("RPC: %5u %s: retry garbled creds\n",
2135                                         task->tk_pid, __func__);
2136                         task->tk_action = call_bind;
2137                         goto out_retry;
2138                 case RPC_AUTH_TOOWEAK:
2139                         rcu_read_lock();
2140                         printk(KERN_NOTICE "RPC: server %s requires stronger "
2141                                "authentication.\n",
2142                                rcu_dereference(clnt->cl_xprt)->servername);
2143                         rcu_read_unlock();
2144                         break;
2145                 default:
2146                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
2147                                         task->tk_pid, __func__, n);
2148                         error = -EIO;
2149                 }
2150                 dprintk("RPC: %5u %s: call rejected %d\n",
2151                                 task->tk_pid, __func__, n);
2152                 goto out_err;
2153         }
2154         if (!(p = rpcauth_checkverf(task, p))) {
2155                 dprintk("RPC: %5u %s: auth check failed\n",
2156                                 task->tk_pid, __func__);
2157                 goto out_garbage;               /* bad verifier, retry */
2158         }
2159         len = p - (__be32 *)iov->iov_base - 1;
2160         if (len < 0)
2161                 goto out_overflow;
2162         switch ((n = ntohl(*p++))) {
2163         case RPC_SUCCESS:
2164                 return p;
2165         case RPC_PROG_UNAVAIL:
2166                 dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2167                                 "by server %s\n", task->tk_pid, __func__,
2168                                 (unsigned int)clnt->cl_prog,
2169                                 rcu_dereference(clnt->cl_xprt)->servername);
2170                 error = -EPFNOSUPPORT;
2171                 goto out_err;
2172         case RPC_PROG_MISMATCH:
2173                 dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2174                                 "by server %s\n", task->tk_pid, __func__,
2175                                 (unsigned int)clnt->cl_prog,
2176                                 (unsigned int)clnt->cl_vers,
2177                                 rcu_dereference(clnt->cl_xprt)->servername);
2178                 error = -EPROTONOSUPPORT;
2179                 goto out_err;
2180         case RPC_PROC_UNAVAIL:
2181                 dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2182                                 "version %u on server %s\n",
2183                                 task->tk_pid, __func__,
2184                                 rpc_proc_name(task),
2185                                 clnt->cl_prog, clnt->cl_vers,
2186                                 rcu_dereference(clnt->cl_xprt)->servername);
2187                 error = -EOPNOTSUPP;
2188                 goto out_err;
2189         case RPC_GARBAGE_ARGS:
2190                 dprintk("RPC: %5u %s: server saw garbage\n",
2191                                 task->tk_pid, __func__);
2192                 break;                  /* retry */
2193         default:
2194                 dprintk("RPC: %5u %s: server accept status: %x\n",
2195                                 task->tk_pid, __func__, n);
2196                 /* Also retry */
2197         }
2198 
2199 out_garbage:
2200         clnt->cl_stats->rpcgarbage++;
2201         if (task->tk_garb_retry) {
2202                 task->tk_garb_retry--;
2203                 dprintk("RPC: %5u %s: retrying\n",
2204                                 task->tk_pid, __func__);
2205                 task->tk_action = call_bind;
2206 out_retry:
2207                 return ERR_PTR(-EAGAIN);
2208         }
2209 out_eio:
2210         error = -EIO;
2211 out_err:
2212         rpc_exit(task, error);
2213         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2214                         __func__, error);
2215         return ERR_PTR(error);
2216 out_overflow:
2217         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2218                         __func__);
2219         goto out_garbage;
2220 }
2221 
2222 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2223 {
2224 }
2225 
2226 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2227 {
2228         return 0;
2229 }
2230 
2231 static struct rpc_procinfo rpcproc_null = {
2232         .p_encode = rpcproc_encode_null,
2233         .p_decode = rpcproc_decode_null,
2234 };
2235 
2236 static int rpc_ping(struct rpc_clnt *clnt)
2237 {
2238         struct rpc_message msg = {
2239                 .rpc_proc = &rpcproc_null,
2240         };
2241         int err;
2242         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2243         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2244         put_rpccred(msg.rpc_cred);
2245         return err;
2246 }
2247 
2248 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2249 {
2250         struct rpc_message msg = {
2251                 .rpc_proc = &rpcproc_null,
2252                 .rpc_cred = cred,
2253         };
2254         struct rpc_task_setup task_setup_data = {
2255                 .rpc_client = clnt,
2256                 .rpc_message = &msg,
2257                 .callback_ops = &rpc_default_ops,
2258                 .flags = flags,
2259         };
2260         return rpc_run_task(&task_setup_data);
2261 }
2262 EXPORT_SYMBOL_GPL(rpc_call_null);
2263 
2264 #ifdef RPC_DEBUG
2265 static void rpc_show_header(void)
2266 {
2267         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2268                 "-timeout ---ops--\n");
2269 }
2270 
2271 static void rpc_show_task(const struct rpc_clnt *clnt,
2272                           const struct rpc_task *task)
2273 {
2274         const char *rpc_waitq = "none";
2275 
2276         if (RPC_IS_QUEUED(task))
2277                 rpc_waitq = rpc_qname(task->tk_waitqueue);
2278 
2279         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2280                 task->tk_pid, task->tk_flags, task->tk_status,
2281                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2282                 clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
2283                 task->tk_action, rpc_waitq);
2284 }
2285 
2286 void rpc_show_tasks(struct net *net)
2287 {
2288         struct rpc_clnt *clnt;
2289         struct rpc_task *task;
2290         int header = 0;
2291         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2292 
2293         spin_lock(&sn->rpc_client_lock);
2294         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2295                 spin_lock(&clnt->cl_lock);
2296                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2297                         if (!header) {
2298                                 rpc_show_header();
2299                                 header++;
2300                         }
2301                         rpc_show_task(clnt, task);
2302                 }
2303                 spin_unlock(&clnt->cl_lock);
2304         }
2305         spin_unlock(&sn->rpc_client_lock);
2306 }
2307 #endif
2308 

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