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