SUNRPC: export new RPC client functions with _GPL
[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/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 u32 *    call_header(struct rpc_task *task);
64 static u32 *    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(system_utsname.nodename);
165         if (clnt->cl_nodelen > UNX_MAXNODENAME)
166                 clnt->cl_nodelen = UNX_MAXNODENAME;
167         memcpy(clnt->cl_nodename, system_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_destroy(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         /* Turn off autobind on clones */
265         new->cl_autobind = 0;
266         new->cl_oneshot = 0;
267         new->cl_dead = 0;
268         if (!IS_ERR(new->cl_dentry))
269                 dget(new->cl_dentry);
270         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
271         if (new->cl_auth)
272                 atomic_inc(&new->cl_auth->au_count);
273         new->cl_metrics = rpc_alloc_iostats(clnt);
274         return new;
275 out_no_clnt:
276         printk(KERN_INFO "RPC: out of memory in %s\n", __FUNCTION__);
277         return ERR_PTR(-ENOMEM);
278 }
279
280 /*
281  * Properly shut down an RPC client, terminating all outstanding
282  * requests. Note that we must be certain that cl_oneshot and
283  * cl_dead are cleared, or else the client would be destroyed
284  * when the last task releases it.
285  */
286 int
287 rpc_shutdown_client(struct rpc_clnt *clnt)
288 {
289         dprintk("RPC: shutting down %s client for %s, tasks=%d\n",
290                         clnt->cl_protname, clnt->cl_server,
291                         atomic_read(&clnt->cl_users));
292
293         while (atomic_read(&clnt->cl_users) > 0) {
294                 /* Don't let rpc_release_client destroy us */
295                 clnt->cl_oneshot = 0;
296                 clnt->cl_dead = 0;
297                 rpc_killall_tasks(clnt);
298                 wait_event_timeout(destroy_wait,
299                         !atomic_read(&clnt->cl_users), 1*HZ);
300         }
301
302         if (atomic_read(&clnt->cl_users) < 0) {
303                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
304                                 clnt, atomic_read(&clnt->cl_users));
305 #ifdef RPC_DEBUG
306                 rpc_show_tasks();
307 #endif
308                 BUG();
309         }
310
311         return rpc_destroy_client(clnt);
312 }
313
314 /*
315  * Delete an RPC client
316  */
317 int
318 rpc_destroy_client(struct rpc_clnt *clnt)
319 {
320         if (!atomic_dec_and_test(&clnt->cl_count))
321                 return 1;
322         BUG_ON(atomic_read(&clnt->cl_users) != 0);
323
324         dprintk("RPC: destroying %s client for %s\n",
325                         clnt->cl_protname, clnt->cl_server);
326         if (clnt->cl_auth) {
327                 rpcauth_destroy(clnt->cl_auth);
328                 clnt->cl_auth = NULL;
329         }
330         if (clnt->cl_parent != clnt) {
331                 if (!IS_ERR(clnt->cl_dentry))
332                         dput(clnt->cl_dentry);
333                 rpc_destroy_client(clnt->cl_parent);
334                 goto out_free;
335         }
336         if (!IS_ERR(clnt->cl_dentry)) {
337                 rpc_rmdir(clnt->cl_dentry);
338                 rpc_put_mount();
339         }
340         if (clnt->cl_xprt) {
341                 xprt_destroy(clnt->cl_xprt);
342                 clnt->cl_xprt = NULL;
343         }
344         if (clnt->cl_server != clnt->cl_inline_name)
345                 kfree(clnt->cl_server);
346 out_free:
347         rpc_free_iostats(clnt->cl_metrics);
348         clnt->cl_metrics = NULL;
349         kfree(clnt);
350         return 0;
351 }
352
353 /*
354  * Release an RPC client
355  */
356 void
357 rpc_release_client(struct rpc_clnt *clnt)
358 {
359         dprintk("RPC:      rpc_release_client(%p, %d)\n",
360                                 clnt, atomic_read(&clnt->cl_users));
361
362         if (!atomic_dec_and_test(&clnt->cl_users))
363                 return;
364         wake_up(&destroy_wait);
365         if (clnt->cl_oneshot || clnt->cl_dead)
366                 rpc_destroy_client(clnt);
367 }
368
369 /**
370  * rpc_bind_new_program - bind a new RPC program to an existing client
371  * @old - old rpc_client
372  * @program - rpc program to set
373  * @vers - rpc program version
374  *
375  * Clones the rpc client and sets up a new RPC program. This is mainly
376  * of use for enabling different RPC programs to share the same transport.
377  * The Sun NFSv2/v3 ACL protocol can do this.
378  */
379 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
380                                       struct rpc_program *program,
381                                       int vers)
382 {
383         struct rpc_clnt *clnt;
384         struct rpc_version *version;
385         int err;
386
387         BUG_ON(vers >= program->nrvers || !program->version[vers]);
388         version = program->version[vers];
389         clnt = rpc_clone_client(old);
390         if (IS_ERR(clnt))
391                 goto out;
392         clnt->cl_procinfo = version->procs;
393         clnt->cl_maxproc  = version->nrprocs;
394         clnt->cl_protname = program->name;
395         clnt->cl_prog     = program->number;
396         clnt->cl_vers     = version->number;
397         clnt->cl_stats    = program->stats;
398         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
399         if (err != 0) {
400                 rpc_shutdown_client(clnt);
401                 clnt = ERR_PTR(err);
402         }
403 out:    
404         return clnt;
405 }
406
407 /*
408  * Default callback for async RPC calls
409  */
410 static void
411 rpc_default_callback(struct rpc_task *task, void *data)
412 {
413 }
414
415 static const struct rpc_call_ops rpc_default_ops = {
416         .rpc_call_done = rpc_default_callback,
417 };
418
419 /*
420  *      Export the signal mask handling for synchronous code that
421  *      sleeps on RPC calls
422  */
423 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
424  
425 static void rpc_save_sigmask(sigset_t *oldset, int intr)
426 {
427         unsigned long   sigallow = sigmask(SIGKILL);
428         sigset_t sigmask;
429
430         /* Block all signals except those listed in sigallow */
431         if (intr)
432                 sigallow |= RPC_INTR_SIGNALS;
433         siginitsetinv(&sigmask, sigallow);
434         sigprocmask(SIG_BLOCK, &sigmask, oldset);
435 }
436
437 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
438 {
439         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
440 }
441
442 static inline void rpc_restore_sigmask(sigset_t *oldset)
443 {
444         sigprocmask(SIG_SETMASK, oldset, NULL);
445 }
446
447 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
448 {
449         rpc_save_sigmask(oldset, clnt->cl_intr);
450 }
451
452 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
453 {
454         rpc_restore_sigmask(oldset);
455 }
456
457 /*
458  * New rpc_call implementation
459  */
460 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
461 {
462         struct rpc_task *task;
463         sigset_t        oldset;
464         int             status;
465
466         /* If this client is slain all further I/O fails */
467         if (clnt->cl_dead) 
468                 return -EIO;
469
470         BUG_ON(flags & RPC_TASK_ASYNC);
471
472         status = -ENOMEM;
473         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
474         if (task == NULL)
475                 goto out;
476
477         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
478         rpc_task_sigmask(task, &oldset);
479
480         rpc_call_setup(task, msg, 0);
481
482         /* Set up the call info struct and execute the task */
483         status = task->tk_status;
484         if (status == 0) {
485                 atomic_inc(&task->tk_count);
486                 status = rpc_execute(task);
487                 if (status == 0)
488                         status = task->tk_status;
489         }
490         rpc_restore_sigmask(&oldset);
491         rpc_release_task(task);
492 out:
493         return status;
494 }
495
496 /*
497  * New rpc_call implementation
498  */
499 int
500 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
501                const struct rpc_call_ops *tk_ops, void *data)
502 {
503         struct rpc_task *task;
504         sigset_t        oldset;
505         int             status;
506
507         /* If this client is slain all further I/O fails */
508         status = -EIO;
509         if (clnt->cl_dead) 
510                 goto out_release;
511
512         flags |= RPC_TASK_ASYNC;
513
514         /* Create/initialize a new RPC task */
515         status = -ENOMEM;
516         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
517                 goto out_release;
518
519         /* Mask signals on GSS_AUTH upcalls */
520         rpc_task_sigmask(task, &oldset);                
521
522         rpc_call_setup(task, msg, 0);
523
524         /* Set up the call info struct and execute the task */
525         status = task->tk_status;
526         if (status == 0)
527                 rpc_execute(task);
528         else
529                 rpc_release_task(task);
530
531         rpc_restore_sigmask(&oldset);           
532         return status;
533 out_release:
534         if (tk_ops->rpc_release != NULL)
535                 tk_ops->rpc_release(data);
536         return status;
537 }
538
539
540 void
541 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
542 {
543         task->tk_msg   = *msg;
544         task->tk_flags |= flags;
545         /* Bind the user cred */
546         if (task->tk_msg.rpc_cred != NULL)
547                 rpcauth_holdcred(task);
548         else
549                 rpcauth_bindcred(task);
550
551         if (task->tk_status == 0)
552                 task->tk_action = call_start;
553         else
554                 task->tk_action = rpc_exit_task;
555 }
556
557 /**
558  * rpc_peeraddr - extract remote peer address from clnt's xprt
559  * @clnt: RPC client structure
560  * @buf: target buffer
561  * @size: length of target buffer
562  *
563  * Returns the number of bytes that are actually in the stored address.
564  */
565 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
566 {
567         size_t bytes;
568         struct rpc_xprt *xprt = clnt->cl_xprt;
569
570         bytes = sizeof(xprt->addr);
571         if (bytes > bufsize)
572                 bytes = bufsize;
573         memcpy(buf, &clnt->cl_xprt->addr, bytes);
574         return xprt->addrlen;
575 }
576 EXPORT_SYMBOL_GPL(rpc_peeraddr);
577
578 /**
579  * rpc_peeraddr2str - return remote peer address in printable format
580  * @clnt: RPC client structure
581  * @format: address format
582  *
583  */
584 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
585 {
586         struct rpc_xprt *xprt = clnt->cl_xprt;
587         return xprt->ops->print_addr(xprt, format);
588 }
589 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
590
591 void
592 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
593 {
594         struct rpc_xprt *xprt = clnt->cl_xprt;
595         if (xprt->ops->set_buffer_size)
596                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
597 }
598
599 /*
600  * Return size of largest payload RPC client can support, in bytes
601  *
602  * For stream transports, this is one RPC record fragment (see RFC
603  * 1831), as we don't support multi-record requests yet.  For datagram
604  * transports, this is the size of an IP packet minus the IP, UDP, and
605  * RPC header sizes.
606  */
607 size_t rpc_max_payload(struct rpc_clnt *clnt)
608 {
609         return clnt->cl_xprt->max_payload;
610 }
611 EXPORT_SYMBOL_GPL(rpc_max_payload);
612
613 /**
614  * rpc_force_rebind - force transport to check that remote port is unchanged
615  * @clnt: client to rebind
616  *
617  */
618 void rpc_force_rebind(struct rpc_clnt *clnt)
619 {
620         if (clnt->cl_autobind)
621                 xprt_clear_bound(clnt->cl_xprt);
622 }
623 EXPORT_SYMBOL_GPL(rpc_force_rebind);
624
625 /*
626  * Restart an (async) RPC call. Usually called from within the
627  * exit handler.
628  */
629 void
630 rpc_restart_call(struct rpc_task *task)
631 {
632         if (RPC_ASSASSINATED(task))
633                 return;
634
635         task->tk_action = call_start;
636 }
637
638 /*
639  * 0.  Initial state
640  *
641  *     Other FSM states can be visited zero or more times, but
642  *     this state is visited exactly once for each RPC.
643  */
644 static void
645 call_start(struct rpc_task *task)
646 {
647         struct rpc_clnt *clnt = task->tk_client;
648
649         dprintk("RPC: %4d call_start %s%d proc %d (%s)\n", task->tk_pid,
650                 clnt->cl_protname, clnt->cl_vers, task->tk_msg.rpc_proc->p_proc,
651                 (RPC_IS_ASYNC(task) ? "async" : "sync"));
652
653         /* Increment call count */
654         task->tk_msg.rpc_proc->p_count++;
655         clnt->cl_stats->rpccnt++;
656         task->tk_action = call_reserve;
657 }
658
659 /*
660  * 1.   Reserve an RPC call slot
661  */
662 static void
663 call_reserve(struct rpc_task *task)
664 {
665         dprintk("RPC: %4d call_reserve\n", task->tk_pid);
666
667         if (!rpcauth_uptodatecred(task)) {
668                 task->tk_action = call_refresh;
669                 return;
670         }
671
672         task->tk_status  = 0;
673         task->tk_action  = call_reserveresult;
674         xprt_reserve(task);
675 }
676
677 /*
678  * 1b.  Grok the result of xprt_reserve()
679  */
680 static void
681 call_reserveresult(struct rpc_task *task)
682 {
683         int status = task->tk_status;
684
685         dprintk("RPC: %4d call_reserveresult (status %d)\n",
686                                 task->tk_pid, task->tk_status);
687
688         /*
689          * After a call to xprt_reserve(), we must have either
690          * a request slot or else an error status.
691          */
692         task->tk_status = 0;
693         if (status >= 0) {
694                 if (task->tk_rqstp) {
695                         task->tk_action = call_allocate;
696                         return;
697                 }
698
699                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
700                                 __FUNCTION__, status);
701                 rpc_exit(task, -EIO);
702                 return;
703         }
704
705         /*
706          * Even though there was an error, we may have acquired
707          * a request slot somehow.  Make sure not to leak it.
708          */
709         if (task->tk_rqstp) {
710                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
711                                 __FUNCTION__, status);
712                 xprt_release(task);
713         }
714
715         switch (status) {
716         case -EAGAIN:   /* woken up; retry */
717                 task->tk_action = call_reserve;
718                 return;
719         case -EIO:      /* probably a shutdown */
720                 break;
721         default:
722                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
723                                 __FUNCTION__, status);
724                 break;
725         }
726         rpc_exit(task, status);
727 }
728
729 /*
730  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
731  *      (Note: buffer memory is freed in xprt_release).
732  */
733 static void
734 call_allocate(struct rpc_task *task)
735 {
736         struct rpc_rqst *req = task->tk_rqstp;
737         struct rpc_xprt *xprt = task->tk_xprt;
738         unsigned int    bufsiz;
739
740         dprintk("RPC: %4d call_allocate (status %d)\n", 
741                                 task->tk_pid, task->tk_status);
742         task->tk_action = call_bind;
743         if (req->rq_buffer)
744                 return;
745
746         /* FIXME: compute buffer requirements more exactly using
747          * auth->au_wslack */
748         bufsiz = task->tk_msg.rpc_proc->p_bufsiz + RPC_SLACK_SPACE;
749
750         if (xprt->ops->buf_alloc(task, bufsiz << 1) != NULL)
751                 return;
752         printk(KERN_INFO "RPC: buffer allocation failed for task %p\n", task); 
753
754         if (RPC_IS_ASYNC(task) || !signalled()) {
755                 xprt_release(task);
756                 task->tk_action = call_reserve;
757                 rpc_delay(task, HZ>>4);
758                 return;
759         }
760
761         rpc_exit(task, -ERESTARTSYS);
762 }
763
764 static inline int
765 rpc_task_need_encode(struct rpc_task *task)
766 {
767         return task->tk_rqstp->rq_snd_buf.len == 0;
768 }
769
770 static inline void
771 rpc_task_force_reencode(struct rpc_task *task)
772 {
773         task->tk_rqstp->rq_snd_buf.len = 0;
774 }
775
776 /*
777  * 3.   Encode arguments of an RPC call
778  */
779 static void
780 call_encode(struct rpc_task *task)
781 {
782         struct rpc_rqst *req = task->tk_rqstp;
783         struct xdr_buf *sndbuf = &req->rq_snd_buf;
784         struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
785         unsigned int    bufsiz;
786         kxdrproc_t      encode;
787         u32             *p;
788
789         dprintk("RPC: %4d call_encode (status %d)\n", 
790                                 task->tk_pid, task->tk_status);
791
792         /* Default buffer setup */
793         bufsiz = req->rq_bufsize >> 1;
794         sndbuf->head[0].iov_base = (void *)req->rq_buffer;
795         sndbuf->head[0].iov_len  = bufsiz;
796         sndbuf->tail[0].iov_len  = 0;
797         sndbuf->page_len         = 0;
798         sndbuf->len              = 0;
799         sndbuf->buflen           = bufsiz;
800         rcvbuf->head[0].iov_base = (void *)((char *)req->rq_buffer + bufsiz);
801         rcvbuf->head[0].iov_len  = bufsiz;
802         rcvbuf->tail[0].iov_len  = 0;
803         rcvbuf->page_len         = 0;
804         rcvbuf->len              = 0;
805         rcvbuf->buflen           = bufsiz;
806
807         /* Encode header and provided arguments */
808         encode = task->tk_msg.rpc_proc->p_encode;
809         if (!(p = call_header(task))) {
810                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
811                 rpc_exit(task, -EIO);
812                 return;
813         }
814         if (encode == NULL)
815                 return;
816
817         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
818                         task->tk_msg.rpc_argp);
819         if (task->tk_status == -ENOMEM) {
820                 /* XXX: Is this sane? */
821                 rpc_delay(task, 3*HZ);
822                 task->tk_status = -EAGAIN;
823         }
824 }
825
826 /*
827  * 4.   Get the server port number if not yet set
828  */
829 static void
830 call_bind(struct rpc_task *task)
831 {
832         struct rpc_xprt *xprt = task->tk_xprt;
833
834         dprintk("RPC: %4d call_bind (status %d)\n",
835                                 task->tk_pid, task->tk_status);
836
837         task->tk_action = call_connect;
838         if (!xprt_bound(xprt)) {
839                 task->tk_action = call_bind_status;
840                 task->tk_timeout = xprt->bind_timeout;
841                 xprt->ops->rpcbind(task);
842         }
843 }
844
845 /*
846  * 4a.  Sort out bind result
847  */
848 static void
849 call_bind_status(struct rpc_task *task)
850 {
851         int status = -EACCES;
852
853         if (task->tk_status >= 0) {
854                 dprintk("RPC: %4d call_bind_status (status %d)\n",
855                                         task->tk_pid, task->tk_status);
856                 task->tk_status = 0;
857                 task->tk_action = call_connect;
858                 return;
859         }
860
861         switch (task->tk_status) {
862         case -EACCES:
863                 dprintk("RPC: %4d remote rpcbind: RPC program/version unavailable\n",
864                                 task->tk_pid);
865                 rpc_delay(task, 3*HZ);
866                 goto retry_bind;
867         case -ETIMEDOUT:
868                 dprintk("RPC: %4d rpcbind request timed out\n",
869                                 task->tk_pid);
870                 if (RPC_IS_SOFT(task)) {
871                         status = -EIO;
872                         break;
873                 }
874                 goto retry_bind;
875         case -EPFNOSUPPORT:
876                 dprintk("RPC: %4d remote rpcbind service unavailable\n",
877                                 task->tk_pid);
878                 break;
879         case -EPROTONOSUPPORT:
880                 dprintk("RPC: %4d remote rpcbind version 2 unavailable\n",
881                                 task->tk_pid);
882                 break;
883         default:
884                 dprintk("RPC: %4d unrecognized rpcbind error (%d)\n",
885                                 task->tk_pid, -task->tk_status);
886                 status = -EIO;
887                 break;
888         }
889
890         rpc_exit(task, status);
891         return;
892
893 retry_bind:
894         task->tk_status = 0;
895         task->tk_action = call_bind;
896         return;
897 }
898
899 /*
900  * 4b.  Connect to the RPC server
901  */
902 static void
903 call_connect(struct rpc_task *task)
904 {
905         struct rpc_xprt *xprt = task->tk_xprt;
906
907         dprintk("RPC: %4d call_connect xprt %p %s connected\n",
908                         task->tk_pid, xprt,
909                         (xprt_connected(xprt) ? "is" : "is not"));
910
911         task->tk_action = call_transmit;
912         if (!xprt_connected(xprt)) {
913                 task->tk_action = call_connect_status;
914                 if (task->tk_status < 0)
915                         return;
916                 xprt_connect(task);
917         }
918 }
919
920 /*
921  * 4c.  Sort out connect result
922  */
923 static void
924 call_connect_status(struct rpc_task *task)
925 {
926         struct rpc_clnt *clnt = task->tk_client;
927         int status = task->tk_status;
928
929         dprintk("RPC: %5u call_connect_status (status %d)\n", 
930                                 task->tk_pid, task->tk_status);
931
932         task->tk_status = 0;
933         if (status >= 0) {
934                 clnt->cl_stats->netreconn++;
935                 task->tk_action = call_transmit;
936                 return;
937         }
938
939         /* Something failed: remote service port may have changed */
940         rpc_force_rebind(clnt);
941
942         switch (status) {
943         case -ENOTCONN:
944         case -ETIMEDOUT:
945         case -EAGAIN:
946                 task->tk_action = call_bind;
947                 break;
948         default:
949                 rpc_exit(task, -EIO);
950                 break;
951         }
952 }
953
954 /*
955  * 5.   Transmit the RPC request, and wait for reply
956  */
957 static void
958 call_transmit(struct rpc_task *task)
959 {
960         dprintk("RPC: %4d call_transmit (status %d)\n", 
961                                 task->tk_pid, task->tk_status);
962
963         task->tk_action = call_status;
964         if (task->tk_status < 0)
965                 return;
966         task->tk_status = xprt_prepare_transmit(task);
967         if (task->tk_status != 0)
968                 return;
969         task->tk_action = call_transmit_status;
970         /* Encode here so that rpcsec_gss can use correct sequence number. */
971         if (rpc_task_need_encode(task)) {
972                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
973                 call_encode(task);
974                 /* Did the encode result in an error condition? */
975                 if (task->tk_status != 0)
976                         return;
977         }
978         xprt_transmit(task);
979         if (task->tk_status < 0)
980                 return;
981         /*
982          * On success, ensure that we call xprt_end_transmit() before sleeping
983          * in order to allow access to the socket to other RPC requests.
984          */
985         call_transmit_status(task);
986         if (task->tk_msg.rpc_proc->p_decode != NULL)
987                 return;
988         task->tk_action = rpc_exit_task;
989         rpc_wake_up_task(task);
990 }
991
992 /*
993  * 5a.  Handle cleanup after a transmission
994  */
995 static void
996 call_transmit_status(struct rpc_task *task)
997 {
998         task->tk_action = call_status;
999         /*
1000          * Special case: if we've been waiting on the socket's write_space()
1001          * callback, then don't call xprt_end_transmit().
1002          */
1003         if (task->tk_status == -EAGAIN)
1004                 return;
1005         xprt_end_transmit(task);
1006         rpc_task_force_reencode(task);
1007 }
1008
1009 /*
1010  * 6.   Sort out the RPC call status
1011  */
1012 static void
1013 call_status(struct rpc_task *task)
1014 {
1015         struct rpc_clnt *clnt = task->tk_client;
1016         struct rpc_rqst *req = task->tk_rqstp;
1017         int             status;
1018
1019         if (req->rq_received > 0 && !req->rq_bytes_sent)
1020                 task->tk_status = req->rq_received;
1021
1022         dprintk("RPC: %4d call_status (status %d)\n", 
1023                                 task->tk_pid, task->tk_status);
1024
1025         status = task->tk_status;
1026         if (status >= 0) {
1027                 task->tk_action = call_decode;
1028                 return;
1029         }
1030
1031         task->tk_status = 0;
1032         switch(status) {
1033         case -ETIMEDOUT:
1034                 task->tk_action = call_timeout;
1035                 break;
1036         case -ECONNREFUSED:
1037         case -ENOTCONN:
1038                 rpc_force_rebind(clnt);
1039                 task->tk_action = call_bind;
1040                 break;
1041         case -EAGAIN:
1042                 task->tk_action = call_transmit;
1043                 break;
1044         case -EIO:
1045                 /* shutdown or soft timeout */
1046                 rpc_exit(task, status);
1047                 break;
1048         default:
1049                 printk("%s: RPC call returned error %d\n",
1050                                clnt->cl_protname, -status);
1051                 rpc_exit(task, status);
1052                 break;
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         u32             *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                 printk(KERN_WARNING "%s: too small RPC reply size (%d bytes)\n",
1121                         clnt->cl_protname, task->tk_status);
1122                 rpc_exit(task, -EIO);
1123                 return;
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 u32 *
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         u32             *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 u32 *
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         u32     *p = iov->iov_base, n;
1230         int error = -EACCES;
1231
1232         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1233                 /* RFC-1014 says that the representation of XDR data must be a
1234                  * multiple of four bytes
1235                  * - if it isn't pointer subtraction in the NFS client may give
1236                  *   undefined results
1237                  */
1238                 printk(KERN_WARNING
1239                        "call_verify: XDR representation not a multiple of"
1240                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1241                 goto out_eio;
1242         }
1243         if ((len -= 3) < 0)
1244                 goto out_overflow;
1245         p += 1; /* skip XID */
1246
1247         if ((n = ntohl(*p++)) != RPC_REPLY) {
1248                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1249                 goto out_garbage;
1250         }
1251         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1252                 if (--len < 0)
1253                         goto out_overflow;
1254                 switch ((n = ntohl(*p++))) {
1255                         case RPC_AUTH_ERROR:
1256                                 break;
1257                         case RPC_MISMATCH:
1258                                 dprintk("%s: RPC call version mismatch!\n", __FUNCTION__);
1259                                 error = -EPROTONOSUPPORT;
1260                                 goto out_err;
1261                         default:
1262                                 dprintk("%s: RPC call rejected, unknown error: %x\n", __FUNCTION__, n);
1263                                 goto out_eio;
1264                 }
1265                 if (--len < 0)
1266                         goto out_overflow;
1267                 switch ((n = ntohl(*p++))) {
1268                 case RPC_AUTH_REJECTEDCRED:
1269                 case RPC_AUTH_REJECTEDVERF:
1270                 case RPCSEC_GSS_CREDPROBLEM:
1271                 case RPCSEC_GSS_CTXPROBLEM:
1272                         if (!task->tk_cred_retry)
1273                                 break;
1274                         task->tk_cred_retry--;
1275                         dprintk("RPC: %4d call_verify: retry stale creds\n",
1276                                                         task->tk_pid);
1277                         rpcauth_invalcred(task);
1278                         task->tk_action = call_refresh;
1279                         goto out_retry;
1280                 case RPC_AUTH_BADCRED:
1281                 case RPC_AUTH_BADVERF:
1282                         /* possibly garbled cred/verf? */
1283                         if (!task->tk_garb_retry)
1284                                 break;
1285                         task->tk_garb_retry--;
1286                         dprintk("RPC: %4d call_verify: retry garbled creds\n",
1287                                                         task->tk_pid);
1288                         task->tk_action = call_bind;
1289                         goto out_retry;
1290                 case RPC_AUTH_TOOWEAK:
1291                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1292                                "authentication.\n", task->tk_client->cl_server);
1293                         break;
1294                 default:
1295                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1296                         error = -EIO;
1297                 }
1298                 dprintk("RPC: %4d call_verify: call rejected %d\n",
1299                                                 task->tk_pid, n);
1300                 goto out_err;
1301         }
1302         if (!(p = rpcauth_checkverf(task, p))) {
1303                 printk(KERN_WARNING "call_verify: auth check failed\n");
1304                 goto out_garbage;               /* bad verifier, retry */
1305         }
1306         len = p - (u32 *)iov->iov_base - 1;
1307         if (len < 0)
1308                 goto out_overflow;
1309         switch ((n = ntohl(*p++))) {
1310         case RPC_SUCCESS:
1311                 return p;
1312         case RPC_PROG_UNAVAIL:
1313                 dprintk("RPC: call_verify: program %u is unsupported by server %s\n",
1314                                 (unsigned int)task->tk_client->cl_prog,
1315                                 task->tk_client->cl_server);
1316                 error = -EPFNOSUPPORT;
1317                 goto out_err;
1318         case RPC_PROG_MISMATCH:
1319                 dprintk("RPC: call_verify: program %u, version %u unsupported by server %s\n",
1320                                 (unsigned int)task->tk_client->cl_prog,
1321                                 (unsigned int)task->tk_client->cl_vers,
1322                                 task->tk_client->cl_server);
1323                 error = -EPROTONOSUPPORT;
1324                 goto out_err;
1325         case RPC_PROC_UNAVAIL:
1326                 dprintk("RPC: call_verify: proc %p unsupported by program %u, version %u on server %s\n",
1327                                 task->tk_msg.rpc_proc,
1328                                 task->tk_client->cl_prog,
1329                                 task->tk_client->cl_vers,
1330                                 task->tk_client->cl_server);
1331                 error = -EOPNOTSUPP;
1332                 goto out_err;
1333         case RPC_GARBAGE_ARGS:
1334                 dprintk("RPC: %4d %s: server saw garbage\n", task->tk_pid, __FUNCTION__);
1335                 break;                  /* retry */
1336         default:
1337                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1338                 /* Also retry */
1339         }
1340
1341 out_garbage:
1342         task->tk_client->cl_stats->rpcgarbage++;
1343         if (task->tk_garb_retry) {
1344                 task->tk_garb_retry--;
1345                 dprintk("RPC %s: retrying %4d\n", __FUNCTION__, task->tk_pid);
1346                 task->tk_action = call_bind;
1347 out_retry:
1348                 return ERR_PTR(-EAGAIN);
1349         }
1350         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1351 out_eio:
1352         error = -EIO;
1353 out_err:
1354         rpc_exit(task, error);
1355         return ERR_PTR(error);
1356 out_overflow:
1357         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1358         goto out_garbage;
1359 }
1360
1361 static int rpcproc_encode_null(void *rqstp, u32 *data, void *obj)
1362 {
1363         return 0;
1364 }
1365
1366 static int rpcproc_decode_null(void *rqstp, u32 *data, void *obj)
1367 {
1368         return 0;
1369 }
1370
1371 static struct rpc_procinfo rpcproc_null = {
1372         .p_encode = rpcproc_encode_null,
1373         .p_decode = rpcproc_decode_null,
1374 };
1375
1376 int rpc_ping(struct rpc_clnt *clnt, int flags)
1377 {
1378         struct rpc_message msg = {
1379                 .rpc_proc = &rpcproc_null,
1380         };
1381         int err;
1382         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1383         err = rpc_call_sync(clnt, &msg, flags);
1384         put_rpccred(msg.rpc_cred);
1385         return err;
1386 }