Merge ../linus
[linux-2.6] / net / sunrpc / clnt.c
1 /*
2  *  linux/net/sunrpc/clnt.c
3  *
4  *  This file contains the high-level RPC interface.
5  *  It is modeled as a finite state machine to support both synchronous
6  *  and asynchronous requests.
7  *
8  *  -   RPC header generation and argument serialization.
9  *  -   Credential refresh.
10  *  -   TCP connect handling.
11  *  -   Retry of operation when it is suspected the operation failed because
12  *      of uid squashing on the server, or when the credentials were stale
13  *      and need to be refreshed, or when a packet was damaged in transit.
14  *      This may be have to be moved to the VFS layer.
15  *
16  *  NB: BSD uses a more intelligent approach to guessing when a request
17  *  or reply has been lost by keeping the RTO estimate for each procedure.
18  *  We currently make do with a constant timeout value.
19  *
20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
22  */
23
24 #include <asm/system.h>
25
26 #include <linux/module.h>
27 #include <linux/types.h>
28 #include <linux/mm.h>
29 #include <linux/slab.h>
30 #include <linux/smp_lock.h>
31 #include <linux/utsname.h>
32 #include <linux/workqueue.h>
33
34 #include <linux/sunrpc/clnt.h>
35 #include <linux/sunrpc/rpc_pipe_fs.h>
36 #include <linux/sunrpc/metrics.h>
37
38
39 #define RPC_SLACK_SPACE         (1024)  /* total overkill */
40
41 #ifdef RPC_DEBUG
42 # define RPCDBG_FACILITY        RPCDBG_CALL
43 #endif
44
45 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
46
47
48 static void     call_start(struct rpc_task *task);
49 static void     call_reserve(struct rpc_task *task);
50 static void     call_reserveresult(struct rpc_task *task);
51 static void     call_allocate(struct rpc_task *task);
52 static void     call_encode(struct rpc_task *task);
53 static void     call_decode(struct rpc_task *task);
54 static void     call_bind(struct rpc_task *task);
55 static void     call_bind_status(struct rpc_task *task);
56 static void     call_transmit(struct rpc_task *task);
57 static void     call_status(struct rpc_task *task);
58 static void     call_transmit_status(struct rpc_task *task);
59 static void     call_refresh(struct rpc_task *task);
60 static void     call_refreshresult(struct rpc_task *task);
61 static void     call_timeout(struct rpc_task *task);
62 static void     call_connect(struct rpc_task *task);
63 static void     call_connect_status(struct rpc_task *task);
64 static __be32 * call_header(struct rpc_task *task);
65 static __be32 * call_verify(struct rpc_task *task);
66
67
68 static int
69 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
70 {
71         static uint32_t clntid;
72         int error;
73
74         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
75         clnt->cl_dentry = ERR_PTR(-ENOENT);
76         if (dir_name == NULL)
77                 return 0;
78
79         clnt->cl_vfsmnt = rpc_get_mount();
80         if (IS_ERR(clnt->cl_vfsmnt))
81                 return PTR_ERR(clnt->cl_vfsmnt);
82
83         for (;;) {
84                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
85                                 "%s/clnt%x", dir_name,
86                                 (unsigned int)clntid++);
87                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
88                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
89                 if (!IS_ERR(clnt->cl_dentry))
90                         return 0;
91                 error = PTR_ERR(clnt->cl_dentry);
92                 if (error != -EEXIST) {
93                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
94                                         clnt->cl_pathname, error);
95                         rpc_put_mount();
96                         return error;
97                 }
98         }
99 }
100
101 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
102 {
103         struct rpc_version      *version;
104         struct rpc_clnt         *clnt = NULL;
105         struct rpc_auth         *auth;
106         int err;
107         int len;
108
109         dprintk("RPC: creating %s client for %s (xprt %p)\n",
110                 program->name, servname, xprt);
111
112         err = -EINVAL;
113         if (!xprt)
114                 goto out_no_xprt;
115         if (vers >= program->nrvers || !(version = program->version[vers]))
116                 goto out_err;
117
118         err = -ENOMEM;
119         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
120         if (!clnt)
121                 goto out_err;
122         atomic_set(&clnt->cl_users, 0);
123         atomic_set(&clnt->cl_count, 1);
124         clnt->cl_parent = clnt;
125
126         clnt->cl_server = clnt->cl_inline_name;
127         len = strlen(servname) + 1;
128         if (len > sizeof(clnt->cl_inline_name)) {
129                 char *buf = kmalloc(len, GFP_KERNEL);
130                 if (buf != 0)
131                         clnt->cl_server = buf;
132                 else
133                         len = sizeof(clnt->cl_inline_name);
134         }
135         strlcpy(clnt->cl_server, servname, len);
136
137         clnt->cl_xprt     = xprt;
138         clnt->cl_procinfo = version->procs;
139         clnt->cl_maxproc  = version->nrprocs;
140         clnt->cl_protname = program->name;
141         clnt->cl_prog     = program->number;
142         clnt->cl_vers     = version->number;
143         clnt->cl_stats    = program->stats;
144         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
145         err = -ENOMEM;
146         if (clnt->cl_metrics == NULL)
147                 goto out_no_stats;
148         clnt->cl_program  = program;
149
150         if (!xprt_bound(clnt->cl_xprt))
151                 clnt->cl_autobind = 1;
152
153         clnt->cl_rtt = &clnt->cl_rtt_default;
154         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
155
156         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
157         if (err < 0)
158                 goto out_no_path;
159
160         auth = rpcauth_create(flavor, clnt);
161         if (IS_ERR(auth)) {
162                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
163                                 flavor);
164                 err = PTR_ERR(auth);
165                 goto out_no_auth;
166         }
167
168         /* save the nodename */
169         clnt->cl_nodelen = strlen(utsname()->nodename);
170         if (clnt->cl_nodelen > UNX_MAXNODENAME)
171                 clnt->cl_nodelen = UNX_MAXNODENAME;
172         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
173         return clnt;
174
175 out_no_auth:
176         if (!IS_ERR(clnt->cl_dentry)) {
177                 rpc_rmdir(clnt->cl_dentry);
178                 rpc_put_mount();
179         }
180 out_no_path:
181         rpc_free_iostats(clnt->cl_metrics);
182 out_no_stats:
183         if (clnt->cl_server != clnt->cl_inline_name)
184                 kfree(clnt->cl_server);
185         kfree(clnt);
186 out_err:
187         xprt_put(xprt);
188 out_no_xprt:
189         return ERR_PTR(err);
190 }
191
192 /*
193  * rpc_create - create an RPC client and transport with one call
194  * @args: rpc_clnt create argument structure
195  *
196  * Creates and initializes an RPC transport and an RPC client.
197  *
198  * It can ping the server in order to determine if it is up, and to see if
199  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
200  * this behavior so asynchronous tasks can also use rpc_create.
201  */
202 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
203 {
204         struct rpc_xprt *xprt;
205         struct rpc_clnt *clnt;
206
207         xprt = xprt_create_transport(args->protocol, args->address,
208                                         args->addrsize, args->timeout);
209         if (IS_ERR(xprt))
210                 return (struct rpc_clnt *)xprt;
211
212         /*
213          * By default, kernel RPC client connects from a reserved port.
214          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
215          * but it is always enabled for rpciod, which handles the connect
216          * operation.
217          */
218         xprt->resvport = 1;
219         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
220                 xprt->resvport = 0;
221
222         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
223                 args->program->name, args->servername, xprt);
224
225         clnt = rpc_new_client(xprt, args->servername, args->program,
226                                 args->version, args->authflavor);
227         if (IS_ERR(clnt))
228                 return clnt;
229
230         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
231                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
232                 if (err != 0) {
233                         rpc_shutdown_client(clnt);
234                         return ERR_PTR(err);
235                 }
236         }
237
238         clnt->cl_softrtry = 1;
239         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
240                 clnt->cl_softrtry = 0;
241
242         if (args->flags & RPC_CLNT_CREATE_INTR)
243                 clnt->cl_intr = 1;
244         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
245                 clnt->cl_autobind = 1;
246         if (args->flags & RPC_CLNT_CREATE_ONESHOT)
247                 clnt->cl_oneshot = 1;
248
249         return clnt;
250 }
251 EXPORT_SYMBOL_GPL(rpc_create);
252
253 /*
254  * This function clones the RPC client structure. It allows us to share the
255  * same transport while varying parameters such as the authentication
256  * flavour.
257  */
258 struct rpc_clnt *
259 rpc_clone_client(struct rpc_clnt *clnt)
260 {
261         struct rpc_clnt *new;
262         int err = -ENOMEM;
263
264         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
265         if (!new)
266                 goto out_no_clnt;
267         atomic_set(&new->cl_count, 1);
268         atomic_set(&new->cl_users, 0);
269         new->cl_metrics = rpc_alloc_iostats(clnt);
270         if (new->cl_metrics == NULL)
271                 goto out_no_stats;
272         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
273         if (err != 0)
274                 goto out_no_path;
275         new->cl_parent = clnt;
276         atomic_inc(&clnt->cl_count);
277         new->cl_xprt = xprt_get(clnt->cl_xprt);
278         /* Turn off autobind on clones */
279         new->cl_autobind = 0;
280         new->cl_oneshot = 0;
281         new->cl_dead = 0;
282         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
283         if (new->cl_auth)
284                 atomic_inc(&new->cl_auth->au_count);
285         return new;
286 out_no_path:
287         rpc_free_iostats(new->cl_metrics);
288 out_no_stats:
289         kfree(new);
290 out_no_clnt:
291         dprintk("RPC: %s returned error %d\n", __FUNCTION__, err);
292         return ERR_PTR(err);
293 }
294
295 /*
296  * Properly shut down an RPC client, terminating all outstanding
297  * requests. Note that we must be certain that cl_oneshot and
298  * cl_dead are cleared, or else the client would be destroyed
299  * when the last task releases it.
300  */
301 int
302 rpc_shutdown_client(struct rpc_clnt *clnt)
303 {
304         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
305                         clnt->cl_protname, clnt->cl_server,
306                         atomic_read(&clnt->cl_users));
307
308         while (atomic_read(&clnt->cl_users) > 0) {
309                 /* Don't let rpc_release_client destroy us */
310                 clnt->cl_oneshot = 0;
311                 clnt->cl_dead = 0;
312                 rpc_killall_tasks(clnt);
313                 wait_event_timeout(destroy_wait,
314                         !atomic_read(&clnt->cl_users), 1*HZ);
315         }
316
317         if (atomic_read(&clnt->cl_users) < 0) {
318                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
319                                 clnt, atomic_read(&clnt->cl_users));
320 #ifdef RPC_DEBUG
321                 rpc_show_tasks();
322 #endif
323                 BUG();
324         }
325
326         return rpc_destroy_client(clnt);
327 }
328
329 /*
330  * Delete an RPC client
331  */
332 int
333 rpc_destroy_client(struct rpc_clnt *clnt)
334 {
335         if (!atomic_dec_and_test(&clnt->cl_count))
336                 return 1;
337         BUG_ON(atomic_read(&clnt->cl_users) != 0);
338
339         dprintk("RPC: destroying %s client for %s\n",
340                         clnt->cl_protname, clnt->cl_server);
341         if (clnt->cl_auth) {
342                 rpcauth_destroy(clnt->cl_auth);
343                 clnt->cl_auth = NULL;
344         }
345         if (!IS_ERR(clnt->cl_dentry)) {
346                 rpc_rmdir(clnt->cl_dentry);
347                 rpc_put_mount();
348         }
349         if (clnt->cl_parent != clnt) {
350                 rpc_destroy_client(clnt->cl_parent);
351                 goto out_free;
352         }
353         if (clnt->cl_server != clnt->cl_inline_name)
354                 kfree(clnt->cl_server);
355 out_free:
356         rpc_free_iostats(clnt->cl_metrics);
357         clnt->cl_metrics = NULL;
358         xprt_put(clnt->cl_xprt);
359         kfree(clnt);
360         return 0;
361 }
362
363 /*
364  * Release an RPC client
365  */
366 void
367 rpc_release_client(struct rpc_clnt *clnt)
368 {
369         dprintk("RPC:      rpc_release_client(%p, %d)\n",
370                                 clnt, atomic_read(&clnt->cl_users));
371
372         if (!atomic_dec_and_test(&clnt->cl_users))
373                 return;
374         wake_up(&destroy_wait);
375         if (clnt->cl_oneshot || clnt->cl_dead)
376                 rpc_destroy_client(clnt);
377 }
378
379 /**
380  * rpc_bind_new_program - bind a new RPC program to an existing client
381  * @old - old rpc_client
382  * @program - rpc program to set
383  * @vers - rpc program version
384  *
385  * Clones the rpc client and sets up a new RPC program. This is mainly
386  * of use for enabling different RPC programs to share the same transport.
387  * The Sun NFSv2/v3 ACL protocol can do this.
388  */
389 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
390                                       struct rpc_program *program,
391                                       int vers)
392 {
393         struct rpc_clnt *clnt;
394         struct rpc_version *version;
395         int err;
396
397         BUG_ON(vers >= program->nrvers || !program->version[vers]);
398         version = program->version[vers];
399         clnt = rpc_clone_client(old);
400         if (IS_ERR(clnt))
401                 goto out;
402         clnt->cl_procinfo = version->procs;
403         clnt->cl_maxproc  = version->nrprocs;
404         clnt->cl_protname = program->name;
405         clnt->cl_prog     = program->number;
406         clnt->cl_vers     = version->number;
407         clnt->cl_stats    = program->stats;
408         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
409         if (err != 0) {
410                 rpc_shutdown_client(clnt);
411                 clnt = ERR_PTR(err);
412         }
413 out:    
414         return clnt;
415 }
416
417 /*
418  * Default callback for async RPC calls
419  */
420 static void
421 rpc_default_callback(struct rpc_task *task, void *data)
422 {
423 }
424
425 static const struct rpc_call_ops rpc_default_ops = {
426         .rpc_call_done = rpc_default_callback,
427 };
428
429 /*
430  *      Export the signal mask handling for synchronous code that
431  *      sleeps on RPC calls
432  */
433 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
434  
435 static void rpc_save_sigmask(sigset_t *oldset, int intr)
436 {
437         unsigned long   sigallow = sigmask(SIGKILL);
438         sigset_t sigmask;
439
440         /* Block all signals except those listed in sigallow */
441         if (intr)
442                 sigallow |= RPC_INTR_SIGNALS;
443         siginitsetinv(&sigmask, sigallow);
444         sigprocmask(SIG_BLOCK, &sigmask, oldset);
445 }
446
447 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
448 {
449         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
450 }
451
452 static inline void rpc_restore_sigmask(sigset_t *oldset)
453 {
454         sigprocmask(SIG_SETMASK, oldset, NULL);
455 }
456
457 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
458 {
459         rpc_save_sigmask(oldset, clnt->cl_intr);
460 }
461
462 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
463 {
464         rpc_restore_sigmask(oldset);
465 }
466
467 /*
468  * New rpc_call implementation
469  */
470 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
471 {
472         struct rpc_task *task;
473         sigset_t        oldset;
474         int             status;
475
476         /* If this client is slain all further I/O fails */
477         if (clnt->cl_dead) 
478                 return -EIO;
479
480         BUG_ON(flags & RPC_TASK_ASYNC);
481
482         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
483         if (task == NULL)
484                 return -ENOMEM;
485
486         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
487         rpc_task_sigmask(task, &oldset);
488
489         rpc_call_setup(task, msg, 0);
490
491         /* Set up the call info struct and execute the task */
492         status = task->tk_status;
493         if (status != 0) {
494                 rpc_release_task(task);
495                 goto out;
496         }
497         atomic_inc(&task->tk_count);
498         status = rpc_execute(task);
499         if (status == 0)
500                 status = task->tk_status;
501         rpc_put_task(task);
502 out:
503         rpc_restore_sigmask(&oldset);
504         return status;
505 }
506
507 /*
508  * New rpc_call implementation
509  */
510 int
511 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
512                const struct rpc_call_ops *tk_ops, void *data)
513 {
514         struct rpc_task *task;
515         sigset_t        oldset;
516         int             status;
517
518         /* If this client is slain all further I/O fails */
519         status = -EIO;
520         if (clnt->cl_dead) 
521                 goto out_release;
522
523         flags |= RPC_TASK_ASYNC;
524
525         /* Create/initialize a new RPC task */
526         status = -ENOMEM;
527         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
528                 goto out_release;
529
530         /* Mask signals on GSS_AUTH upcalls */
531         rpc_task_sigmask(task, &oldset);                
532
533         rpc_call_setup(task, msg, 0);
534
535         /* Set up the call info struct and execute the task */
536         status = task->tk_status;
537         if (status == 0)
538                 rpc_execute(task);
539         else
540                 rpc_release_task(task);
541
542         rpc_restore_sigmask(&oldset);           
543         return status;
544 out_release:
545         rpc_release_calldata(tk_ops, data);
546         return status;
547 }
548
549
550 void
551 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
552 {
553         task->tk_msg   = *msg;
554         task->tk_flags |= flags;
555         /* Bind the user cred */
556         if (task->tk_msg.rpc_cred != NULL)
557                 rpcauth_holdcred(task);
558         else
559                 rpcauth_bindcred(task);
560
561         if (task->tk_status == 0)
562                 task->tk_action = call_start;
563         else
564                 task->tk_action = rpc_exit_task;
565 }
566
567 /**
568  * rpc_peeraddr - extract remote peer address from clnt's xprt
569  * @clnt: RPC client structure
570  * @buf: target buffer
571  * @size: length of target buffer
572  *
573  * Returns the number of bytes that are actually in the stored address.
574  */
575 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
576 {
577         size_t bytes;
578         struct rpc_xprt *xprt = clnt->cl_xprt;
579
580         bytes = sizeof(xprt->addr);
581         if (bytes > bufsize)
582                 bytes = bufsize;
583         memcpy(buf, &clnt->cl_xprt->addr, bytes);
584         return xprt->addrlen;
585 }
586 EXPORT_SYMBOL_GPL(rpc_peeraddr);
587
588 /**
589  * rpc_peeraddr2str - return remote peer address in printable format
590  * @clnt: RPC client structure
591  * @format: address format
592  *
593  */
594 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
595 {
596         struct rpc_xprt *xprt = clnt->cl_xprt;
597
598         if (xprt->address_strings[format] != NULL)
599                 return xprt->address_strings[format];
600         else
601                 return "unprintable";
602 }
603 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
604
605 void
606 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
607 {
608         struct rpc_xprt *xprt = clnt->cl_xprt;
609         if (xprt->ops->set_buffer_size)
610                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
611 }
612
613 /*
614  * Return size of largest payload RPC client can support, in bytes
615  *
616  * For stream transports, this is one RPC record fragment (see RFC
617  * 1831), as we don't support multi-record requests yet.  For datagram
618  * transports, this is the size of an IP packet minus the IP, UDP, and
619  * RPC header sizes.
620  */
621 size_t rpc_max_payload(struct rpc_clnt *clnt)
622 {
623         return clnt->cl_xprt->max_payload;
624 }
625 EXPORT_SYMBOL_GPL(rpc_max_payload);
626
627 /**
628  * rpc_force_rebind - force transport to check that remote port is unchanged
629  * @clnt: client to rebind
630  *
631  */
632 void rpc_force_rebind(struct rpc_clnt *clnt)
633 {
634         if (clnt->cl_autobind)
635                 xprt_clear_bound(clnt->cl_xprt);
636 }
637 EXPORT_SYMBOL_GPL(rpc_force_rebind);
638
639 /*
640  * Restart an (async) RPC call. Usually called from within the
641  * exit handler.
642  */
643 void
644 rpc_restart_call(struct rpc_task *task)
645 {
646         if (RPC_ASSASSINATED(task))
647                 return;
648
649         task->tk_action = call_start;
650 }
651
652 /*
653  * 0.  Initial state
654  *
655  *     Other FSM states can be visited zero or more times, but
656  *     this state is visited exactly once for each RPC.
657  */
658 static void
659 call_start(struct rpc_task *task)
660 {
661         struct rpc_clnt *clnt = task->tk_client;
662
663         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
664                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
665                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
666
667         /* Increment call count */
668         task->tk_msg.rpc_proc->p_count++;
669         clnt->cl_stats->rpccnt++;
670         task->tk_action = call_reserve;
671 }
672
673 /*
674  * 1.   Reserve an RPC call slot
675  */
676 static void
677 call_reserve(struct rpc_task *task)
678 {
679         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
680
681         if (!rpcauth_uptodatecred(task)) {
682                 task->tk_action = call_refresh;
683                 return;
684         }
685
686         task->tk_status  = 0;
687         task->tk_action  = call_reserveresult;
688         xprt_reserve(task);
689 }
690
691 /*
692  * 1b.  Grok the result of xprt_reserve()
693  */
694 static void
695 call_reserveresult(struct rpc_task *task)
696 {
697         int status = task->tk_status;
698
699         dprintk("RPC: %4d call_reserveresult (status %d)\n",
700                                 task->tk_pid, task->tk_status);
701
702         /*
703          * After a call to xprt_reserve(), we must have either
704          * a request slot or else an error status.
705          */
706         task->tk_status = 0;
707         if (status >= 0) {
708                 if (task->tk_rqstp) {
709                         task->tk_action = call_allocate;
710                         return;
711                 }
712
713                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
714                                 __FUNCTION__, status);
715                 rpc_exit(task, -EIO);
716                 return;
717         }
718
719         /*
720          * Even though there was an error, we may have acquired
721          * a request slot somehow.  Make sure not to leak it.
722          */
723         if (task->tk_rqstp) {
724                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
725                                 __FUNCTION__, status);
726                 xprt_release(task);
727         }
728
729         switch (status) {
730         case -EAGAIN:   /* woken up; retry */
731                 task->tk_action = call_reserve;
732                 return;
733         case -EIO:      /* probably a shutdown */
734                 break;
735         default:
736                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
737                                 __FUNCTION__, status);
738                 break;
739         }
740         rpc_exit(task, status);
741 }
742
743 /*
744  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
745  *      (Note: buffer memory is freed in xprt_release).
746  */
747 static void
748 call_allocate(struct rpc_task *task)
749 {
750         struct rpc_rqst *req = task->tk_rqstp;
751         struct rpc_xprt *xprt = task->tk_xprt;
752         unsigned int    bufsiz;
753
754         dprintk("RPC: %4d call_allocate (status %d)\n", 
755                                 task->tk_pid, task->tk_status);
756         task->tk_action = call_bind;
757         if (req->rq_buffer)
758                 return;
759
760         /* FIXME: compute buffer requirements more exactly using
761          * auth->au_wslack */
762         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
763
764         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
765                 return;
766         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task); 
767
768         if (RPC_IS_ASYNC(task) || !signalled()) {
769                 xprt_release(task);
770                 task->tk_action = call_reserve;
771                 rpc_delay(task, HZ>>4);
772                 return;
773         }
774
775         rpc_exit(task, -ERESTARTSYS);
776 }
777
778 static inline int
779 rpc_task_need_encode(struct rpc_task *task)
780 {
781         return task->tk_rqstp->rq_snd_buf.len == 0;
782 }
783
784 static inline void
785 rpc_task_force_reencode(struct rpc_task *task)
786 {
787         task->tk_rqstp->rq_snd_buf.len = 0;
788 }
789
790 /*
791  * 3.   Encode arguments of an RPC call
792  */
793 static void
794 call_encode(struct rpc_task *task)
795 {
796         struct rpc_rqst *req = task->tk_rqstp;
797         struct xdr_buf *sndbuf = &req->rq_snd_buf;
798         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
799         unsigned int    bufsiz;
800         kxdrproc_t      encode;
801         __be32          *p;
802
803         dprintk("RPC: %4d call_encode (status %d)\n", 
804                                 task->tk_pid, task->tk_status);
805
806         /* Default buffer setup */
807         bufsiz = req->rq_bufsize >> 1;
808         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
809         sndbuf->head[0].iov_len  = bufsiz;
810         sndbuf->tail[0].iov_len  = 0;
811         sndbuf->page_len         = 0;
812         sndbuf->len              = 0;
813         sndbuf->buflen           = bufsiz;
814         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
815         rcvbuf->head[0].iov_len  = bufsiz;
816         rcvbuf->tail[0].iov_len  = 0;
817         rcvbuf->page_len         = 0;
818         rcvbuf->len              = 0;
819         rcvbuf->buflen           = bufsiz;
820
821         /* Encode header and provided arguments */
822         encode = task->tk_msg.rpc_proc->p_encode;
823         if (!(p = call_header(task))) {
824                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
825                 rpc_exit(task, -EIO);
826                 return;
827         }
828         if (encode == NULL)
829                 return;
830
831         lock_kernel();
832         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
833                         task->tk_msg.rpc_argp);
834         unlock_kernel();
835         if (task->tk_status == -ENOMEM) {
836                 /* XXX: Is this sane? */
837                 rpc_delay(task, 3*HZ);
838                 task->tk_status = -EAGAIN;
839         }
840 }
841
842 /*
843  * 4.   Get the server port number if not yet set
844  */
845 static void
846 call_bind(struct rpc_task *task)
847 {
848         struct rpc_xprt *xprt = task->tk_xprt;
849
850         dprintk("RPC: %4d call_bind (status %d)\n",
851                                 task->tk_pid, task->tk_status);
852
853         task->tk_action = call_connect;
854         if (!xprt_bound(xprt)) {
855                 task->tk_action = call_bind_status;
856                 task->tk_timeout = xprt->bind_timeout;
857                 xprt->ops->rpcbind(task);
858         }
859 }
860
861 /*
862  * 4a.  Sort out bind result
863  */
864 static void
865 call_bind_status(struct rpc_task *task)
866 {
867         int status = -EACCES;
868
869         if (task->tk_status >= 0) {
870                 dprintk("RPC: %4d call_bind_status (status %d)\n",
871                                         task->tk_pid, task->tk_status);
872                 task->tk_status = 0;
873                 task->tk_action = call_connect;
874                 return;
875         }
876
877         switch (task->tk_status) {
878         case -EACCES:
879                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
880                                 task->tk_pid);
881                 rpc_delay(task, 3*HZ);
882                 goto retry_timeout;
883         case -ETIMEDOUT:
884                 dprintk("RPC: %4d rpcbind request timed out\n",
885                                 task->tk_pid);
886                 goto retry_timeout;
887         case -EPFNOSUPPORT:
888                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
889                                 task->tk_pid);
890                 break;
891         case -EPROTONOSUPPORT:
892                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
893                                 task->tk_pid);
894                 break;
895         default:
896                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
897                                 task->tk_pid, -task->tk_status);
898                 status = -EIO;
899         }
900
901         rpc_exit(task, status);
902         return;
903
904 retry_timeout:
905         task->tk_action = call_timeout;
906 }
907
908 /*
909  * 4b.  Connect to the RPC server
910  */
911 static void
912 call_connect(struct rpc_task *task)
913 {
914         struct rpc_xprt *xprt = task->tk_xprt;
915
916         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
917                         task->tk_pid, xprt,
918                         (xprt_connected(xprt) ? "is" : "is not"));
919
920         task->tk_action = call_transmit;
921         if (!xprt_connected(xprt)) {
922                 task->tk_action = call_connect_status;
923                 if (task->tk_status < 0)
924                         return;
925                 xprt_connect(task);
926         }
927 }
928
929 /*
930  * 4c.  Sort out connect result
931  */
932 static void
933 call_connect_status(struct rpc_task *task)
934 {
935         struct rpc_clnt *clnt = task->tk_client;
936         int status = task->tk_status;
937
938         dprintk("RPC: %5u call_connect_status (status %d)\n", 
939                                 task->tk_pid, task->tk_status);
940
941         task->tk_status = 0;
942         if (status >= 0) {
943                 clnt->cl_stats->netreconn++;
944                 task->tk_action = call_transmit;
945                 return;
946         }
947
948         /* Something failed: remote service port may have changed */
949         rpc_force_rebind(clnt);
950
951         switch (status) {
952         case -ENOTCONN:
953         case -EAGAIN:
954                 task->tk_action = call_bind;
955                 if (!RPC_IS_SOFT(task))
956                         return;
957                 /* if soft mounted, test if we've timed out */
958         case -ETIMEDOUT:
959                 task->tk_action = call_timeout;
960                 return;
961         }
962         rpc_exit(task, -EIO);
963 }
964
965 /*
966  * 5.   Transmit the RPC request, and wait for reply
967  */
968 static void
969 call_transmit(struct rpc_task *task)
970 {
971         dprintk("RPC: %4d call_transmit (status %d)\n", 
972                                 task->tk_pid, task->tk_status);
973
974         task->tk_action = call_status;
975         if (task->tk_status < 0)
976                 return;
977         task->tk_status = xprt_prepare_transmit(task);
978         if (task->tk_status != 0)
979                 return;
980         task->tk_action = call_transmit_status;
981         /* Encode here so that rpcsec_gss can use correct sequence number. */
982         if (rpc_task_need_encode(task)) {
983                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
984                 call_encode(task);
985                 /* Did the encode result in an error condition? */
986                 if (task->tk_status != 0)
987                         return;
988         }
989         xprt_transmit(task);
990         if (task->tk_status < 0)
991                 return;
992         /*
993          * On success, ensure that we call xprt_end_transmit() before sleeping
994          * in order to allow access to the socket to other RPC requests.
995          */
996         call_transmit_status(task);
997         if (task->tk_msg.rpc_proc->p_decode != NULL)
998                 return;
999         task->tk_action = rpc_exit_task;
1000         rpc_wake_up_task(task);
1001 }
1002
1003 /*
1004  * 5a.  Handle cleanup after a transmission
1005  */
1006 static void
1007 call_transmit_status(struct rpc_task *task)
1008 {
1009         task->tk_action = call_status;
1010         /*
1011          * Special case: if we've been waiting on the socket's write_space()
1012          * callback, then don't call xprt_end_transmit().
1013          */
1014         if (task->tk_status == -EAGAIN)
1015                 return;
1016         xprt_end_transmit(task);
1017         rpc_task_force_reencode(task);
1018 }
1019
1020 /*
1021  * 6.   Sort out the RPC call status
1022  */
1023 static void
1024 call_status(struct rpc_task *task)
1025 {
1026         struct rpc_clnt *clnt = task->tk_client;
1027         struct rpc_rqst *req = task->tk_rqstp;
1028         int             status;
1029
1030         if (req->rq_received > 0 && !req->rq_bytes_sent)
1031                 task->tk_status = req->rq_received;
1032
1033         dprintk("RPC: %4d call_status (status %d)\n", 
1034                                 task->tk_pid, task->tk_status);
1035
1036         status = task->tk_status;
1037         if (status >= 0) {
1038                 task->tk_action = call_decode;
1039                 return;
1040         }
1041
1042         task->tk_status = 0;
1043         switch(status) {
1044         case -EHOSTDOWN:
1045         case -EHOSTUNREACH:
1046         case -ENETUNREACH:
1047                 /*
1048                  * Delay any retries for 3 seconds, then handle as if it
1049                  * were a timeout.
1050                  */
1051                 rpc_delay(task, 3*HZ);
1052         case -ETIMEDOUT:
1053                 task->tk_action = call_timeout;
1054                 break;
1055         case -ECONNREFUSED:
1056         case -ENOTCONN:
1057                 rpc_force_rebind(clnt);
1058                 task->tk_action = call_bind;
1059                 break;
1060         case -EAGAIN:
1061                 task->tk_action = call_transmit;
1062                 break;
1063         case -EIO:
1064                 /* shutdown or soft timeout */
1065                 rpc_exit(task, status);
1066                 break;
1067         default:
1068                 printk("%s: RPC call returned error %d\n",
1069                                clnt->cl_protname, -status);
1070                 rpc_exit(task, status);
1071         }
1072 }
1073
1074 /*
1075  * 6a.  Handle RPC timeout
1076  *      We do not release the request slot, so we keep using the
1077  *      same XID for all retransmits.
1078  */
1079 static void
1080 call_timeout(struct rpc_task *task)
1081 {
1082         struct rpc_clnt *clnt = task->tk_client;
1083
1084         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1085                 dprintk("RPC: %4d call_timeout (minor)\n", task->tk_pid);
1086                 goto retry;
1087         }
1088
1089         dprintk("RPC: %4d call_timeout (major)\n", task->tk_pid);
1090         task->tk_timeouts++;
1091
1092         if (RPC_IS_SOFT(task)) {
1093                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1094                                 clnt->cl_protname, clnt->cl_server);
1095                 rpc_exit(task, -EIO);
1096                 return;
1097         }
1098
1099         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1100                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1101                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1102                         clnt->cl_protname, clnt->cl_server);
1103         }
1104         rpc_force_rebind(clnt);
1105
1106 retry:
1107         clnt->cl_stats->rpcretrans++;
1108         task->tk_action = call_bind;
1109         task->tk_status = 0;
1110 }
1111
1112 /*
1113  * 7.   Decode the RPC reply
1114  */
1115 static void
1116 call_decode(struct rpc_task *task)
1117 {
1118         struct rpc_clnt *clnt = task->tk_client;
1119         struct rpc_rqst *req = task->tk_rqstp;
1120         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1121         __be32          *p;
1122
1123         dprintk("RPC: %4d call_decode (status %d)\n", 
1124                                 task->tk_pid, task->tk_status);
1125
1126         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1127                 printk(KERN_NOTICE "%s: server %s OK\n",
1128                         clnt->cl_protname, clnt->cl_server);
1129                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1130         }
1131
1132         if (task->tk_status < 12) {
1133                 if (!RPC_IS_SOFT(task)) {
1134                         task->tk_action = call_bind;
1135                         clnt->cl_stats->rpcretrans++;
1136                         goto out_retry;
1137                 }
1138                 dprintk("%s: too small RPC reply size (%d bytes)\n",
1139                         clnt->cl_protname, task->tk_status);
1140                 task->tk_action = call_timeout;
1141                 goto out_retry;
1142         }
1143
1144         /*
1145          * Ensure that we see all writes made by xprt_complete_rqst()
1146          * before it changed req->rq_received.
1147          */
1148         smp_rmb();
1149         req->rq_rcv_buf.len = req->rq_private_buf.len;
1150
1151         /* Check that the softirq receive buffer is valid */
1152         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1153                                 sizeof(req->rq_rcv_buf)) != 0);
1154
1155         /* Verify the RPC header */
1156         p = call_verify(task);
1157         if (IS_ERR(p)) {
1158                 if (p == ERR_PTR(-EAGAIN))
1159                         goto out_retry;
1160                 return;
1161         }
1162
1163         task->tk_action = rpc_exit_task;
1164
1165         if (decode) {
1166                 lock_kernel();
1167                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1168                                                       task->tk_msg.rpc_resp);
1169                 unlock_kernel();
1170         }
1171         dprintk("RPC: %4d call_decode result %d\n", task->tk_pid,
1172                                         task->tk_status);
1173         return;
1174 out_retry:
1175         req->rq_received = req->rq_private_buf.len = 0;
1176         task->tk_status = 0;
1177 }
1178
1179 /*
1180  * 8.   Refresh the credentials if rejected by the server
1181  */
1182 static void
1183 call_refresh(struct rpc_task *task)
1184 {
1185         dprintk("RPC: %4d call_refresh\n", task->tk_pid);
1186
1187         xprt_release(task);     /* Must do to obtain new XID */
1188         task->tk_action = call_refreshresult;
1189         task->tk_status = 0;
1190         task->tk_client->cl_stats->rpcauthrefresh++;
1191         rpcauth_refreshcred(task);
1192 }
1193
1194 /*
1195  * 8a.  Process the results of a credential refresh
1196  */
1197 static void
1198 call_refreshresult(struct rpc_task *task)
1199 {
1200         int status = task->tk_status;
1201         dprintk("RPC: %4d call_refreshresult (status %d)\n", 
1202                                 task->tk_pid, task->tk_status);
1203
1204         task->tk_status = 0;
1205         task->tk_action = call_reserve;
1206         if (status >= 0 && rpcauth_uptodatecred(task))
1207                 return;
1208         if (status == -EACCES) {
1209                 rpc_exit(task, -EACCES);
1210                 return;
1211         }
1212         task->tk_action = call_refresh;
1213         if (status != -ETIMEDOUT)
1214                 rpc_delay(task, 3*HZ);
1215         return;
1216 }
1217
1218 /*
1219  * Call header serialization
1220  */
1221 static __be32 *
1222 call_header(struct rpc_task *task)
1223 {
1224         struct rpc_clnt *clnt = task->tk_client;
1225         struct rpc_rqst *req = task->tk_rqstp;
1226         __be32          *p = req->rq_svec[0].iov_base;
1227
1228         /* FIXME: check buffer size? */
1229
1230         p = xprt_skip_transport_header(task->tk_xprt, p);
1231         *p++ = req->rq_xid;             /* XID */
1232         *p++ = htonl(RPC_CALL);         /* CALL */
1233         *p++ = htonl(RPC_VERSION);      /* RPC version */
1234         *p++ = htonl(clnt->cl_prog);    /* program number */
1235         *p++ = htonl(clnt->cl_vers);    /* program version */
1236         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1237         p = rpcauth_marshcred(task, p);
1238         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1239         return p;
1240 }
1241
1242 /*
1243  * Reply header verification
1244  */
1245 static __be32 *
1246 call_verify(struct rpc_task *task)
1247 {
1248         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1249         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1250         __be32  *p = iov->iov_base;
1251         u32 n;
1252         int error = -EACCES;
1253
1254         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1255                 /* RFC-1014 says that the representation of XDR data must be a
1256                  * multiple of four bytes
1257                  * - if it isn't pointer subtraction in the NFS client may give
1258                  *   undefined results
1259                  */
1260                 printk(KERN_WARNING
1261                        "call_verify: XDR representation not a multiple of"
1262                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1263                 goto out_eio;
1264         }
1265         if ((len -= 3) < 0)
1266                 goto out_overflow;
1267         p += 1; /* skip XID */
1268
1269         if ((n = ntohl(*p++)) != RPC_REPLY) {
1270                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1271                 goto out_garbage;
1272         }
1273         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1274                 if (--len < 0)
1275                         goto out_overflow;
1276                 switch ((n = ntohl(*p++))) {
1277                         case RPC_AUTH_ERROR:
1278                                 break;
1279                         case RPC_MISMATCH:
1280                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1281                                 error = -EPROTONOSUPPORT;
1282                                 goto out_err;
1283                         default:
1284                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1285                                 goto out_eio;
1286                 }
1287                 if (--len < 0)
1288                         goto out_overflow;
1289                 switch ((n = ntohl(*p++))) {
1290                 case RPC_AUTH_REJECTEDCRED:
1291                 case RPC_AUTH_REJECTEDVERF:
1292                 case RPCSEC_GSS_CREDPROBLEM:
1293                 case RPCSEC_GSS_CTXPROBLEM:
1294                         if (!task->tk_cred_retry)
1295                                 break;
1296                         task->tk_cred_retry--;
1297                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1298                                                         task->tk_pid);
1299                         rpcauth_invalcred(task);
1300                         task->tk_action = call_refresh;
1301                         goto out_retry;
1302                 case RPC_AUTH_BADCRED:
1303                 case RPC_AUTH_BADVERF:
1304                         /* possibly garbled cred/verf? */
1305                         if (!task->tk_garb_retry)
1306                                 break;
1307                         task->tk_garb_retry--;
1308                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1309                                                         task->tk_pid);
1310                         task->tk_action = call_bind;
1311                         goto out_retry;
1312                 case RPC_AUTH_TOOWEAK:
1313                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1314                                "authentication.\n", task->tk_client->cl_server);
1315                         break;
1316                 default:
1317                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1318                         error = -EIO;
1319                 }
1320                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1321                                                 task->tk_pid, n);
1322                 goto out_err;
1323         }
1324         if (!(p = rpcauth_checkverf(task, p))) {
1325                 printk(KERN_WARNING "call_verify: auth check failed\n");
1326                 goto out_garbage;               /* bad verifier, retry */
1327         }
1328         len = p - (__be32 *)iov->iov_base - 1;
1329         if (len < 0)
1330                 goto out_overflow;
1331         switch ((n = ntohl(*p++))) {
1332         case RPC_SUCCESS:
1333                 return p;
1334         case RPC_PROG_UNAVAIL:
1335                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1336                                 (unsigned int)task->tk_client->cl_prog,
1337                                 task->tk_client->cl_server);
1338                 error = -EPFNOSUPPORT;
1339                 goto out_err;
1340         case RPC_PROG_MISMATCH:
1341                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1342                                 (unsigned int)task->tk_client->cl_prog,
1343                                 (unsigned int)task->tk_client->cl_vers,
1344                                 task->tk_client->cl_server);
1345                 error = -EPROTONOSUPPORT;
1346                 goto out_err;
1347         case RPC_PROC_UNAVAIL:
1348                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1349                                 task->tk_msg.rpc_proc,
1350                                 task->tk_client->cl_prog,
1351                                 task->tk_client->cl_vers,
1352                                 task->tk_client->cl_server);
1353                 error = -EOPNOTSUPP;
1354                 goto out_err;
1355         case RPC_GARBAGE_ARGS:
1356                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1357                 break;                  /* retry */
1358         default:
1359                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1360                 /* Also retry */
1361         }
1362
1363 out_garbage:
1364         task->tk_client->cl_stats->rpcgarbage++;
1365         if (task->tk_garb_retry) {
1366                 task->tk_garb_retry--;
1367                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1368                 task->tk_action = call_bind;
1369 out_retry:
1370                 return ERR_PTR(-EAGAIN);
1371         }
1372         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1373 out_eio:
1374         error = -EIO;
1375 out_err:
1376         rpc_exit(task, error);
1377         return ERR_PTR(error);
1378 out_overflow:
1379         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1380         goto out_garbage;
1381 }
1382
1383 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1384 {
1385         return 0;
1386 }
1387
1388 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1389 {
1390         return 0;
1391 }
1392
1393 static struct rpc_procinfo rpcproc_null = {
1394         .p_encode = rpcproc_encode_null,
1395         .p_decode = rpcproc_decode_null,
1396 };
1397
1398 int rpc_ping(struct rpc_clnt *clnt, int flags)
1399 {
1400         struct rpc_message msg = {
1401                 .rpc_proc = &rpcproc_null,
1402         };
1403         int err;
1404         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1405         err = rpc_call_sync(clnt, &msg, flags);
1406         put_rpccred(msg.rpc_cred);
1407         return err;
1408 }