Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfashe...
[linux-2.6] / net / sunrpc / clnt.c
1 /*
2  *  linux/net/sunrpc/clnt.c
3  *
4  *  This file contains the high-level RPC interface.
5  *  It is modeled as a finite state machine to support both synchronous
6  *  and asynchronous requests.
7  *
8  *  -   RPC header generation and argument serialization.
9  *  -   Credential refresh.
10  *  -   TCP connect handling.
11  *  -   Retry of operation when it is suspected the operation failed because
12  *      of uid squashing on the server, or when the credentials were stale
13  *      and need to be refreshed, or when a packet was damaged in transit.
14  *      This may be have to be moved to the VFS layer.
15  *
16  *  NB: BSD uses a more intelligent approach to guessing when a request
17  *  or reply has been lost by keeping the RTO estimate for each procedure.
18  *  We currently make do with a constant timeout value.
19  *
20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
22  */
23
24 #include <asm/system.h>
25
26 #include <linux/module.h>
27 #include <linux/types.h>
28 #include <linux/mm.h>
29 #include <linux/slab.h>
30 #include <linux/smp_lock.h>
31 #include <linux/utsname.h>
32 #include <linux/workqueue.h>
33
34 #include <linux/sunrpc/clnt.h>
35 #include <linux/sunrpc/rpc_pipe_fs.h>
36 #include <linux/sunrpc/metrics.h>
37
38
39 #ifdef RPC_DEBUG
40 # define RPCDBG_FACILITY        RPCDBG_CALL
41 #endif
42
43 #define dprint_status(t)                                        \
44         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
45                         __FUNCTION__, t->tk_status)
46
47 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
48
49
50 static void     call_start(struct rpc_task *task);
51 static void     call_reserve(struct rpc_task *task);
52 static void     call_reserveresult(struct rpc_task *task);
53 static void     call_allocate(struct rpc_task *task);
54 static void     call_encode(struct rpc_task *task);
55 static void     call_decode(struct rpc_task *task);
56 static void     call_bind(struct rpc_task *task);
57 static void     call_bind_status(struct rpc_task *task);
58 static void     call_transmit(struct rpc_task *task);
59 static void     call_status(struct rpc_task *task);
60 static void     call_transmit_status(struct rpc_task *task);
61 static void     call_refresh(struct rpc_task *task);
62 static void     call_refreshresult(struct rpc_task *task);
63 static void     call_timeout(struct rpc_task *task);
64 static void     call_connect(struct rpc_task *task);
65 static void     call_connect_status(struct rpc_task *task);
66 static __be32 * call_header(struct rpc_task *task);
67 static __be32 * call_verify(struct rpc_task *task);
68
69
70 static int
71 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
72 {
73         static uint32_t clntid;
74         int error;
75
76         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
77         clnt->cl_dentry = ERR_PTR(-ENOENT);
78         if (dir_name == NULL)
79                 return 0;
80
81         clnt->cl_vfsmnt = rpc_get_mount();
82         if (IS_ERR(clnt->cl_vfsmnt))
83                 return PTR_ERR(clnt->cl_vfsmnt);
84
85         for (;;) {
86                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
87                                 "%s/clnt%x", dir_name,
88                                 (unsigned int)clntid++);
89                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
90                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
91                 if (!IS_ERR(clnt->cl_dentry))
92                         return 0;
93                 error = PTR_ERR(clnt->cl_dentry);
94                 if (error != -EEXIST) {
95                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
96                                         clnt->cl_pathname, error);
97                         rpc_put_mount();
98                         return error;
99                 }
100         }
101 }
102
103 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
104 {
105         struct rpc_version      *version;
106         struct rpc_clnt         *clnt = NULL;
107         struct rpc_auth         *auth;
108         int err;
109         int len;
110
111         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
112                         program->name, servname, xprt);
113
114         err = -EINVAL;
115         if (!xprt)
116                 goto out_no_xprt;
117         if (vers >= program->nrvers || !(version = program->version[vers]))
118                 goto out_err;
119
120         err = -ENOMEM;
121         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
122         if (!clnt)
123                 goto out_err;
124         atomic_set(&clnt->cl_users, 0);
125         atomic_set(&clnt->cl_count, 1);
126         clnt->cl_parent = clnt;
127
128         clnt->cl_server = clnt->cl_inline_name;
129         len = strlen(servname) + 1;
130         if (len > sizeof(clnt->cl_inline_name)) {
131                 char *buf = kmalloc(len, GFP_KERNEL);
132                 if (buf != 0)
133                         clnt->cl_server = buf;
134                 else
135                         len = sizeof(clnt->cl_inline_name);
136         }
137         strlcpy(clnt->cl_server, servname, len);
138
139         clnt->cl_xprt     = xprt;
140         clnt->cl_procinfo = version->procs;
141         clnt->cl_maxproc  = version->nrprocs;
142         clnt->cl_protname = program->name;
143         clnt->cl_prog     = program->number;
144         clnt->cl_vers     = version->number;
145         clnt->cl_stats    = program->stats;
146         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
147         err = -ENOMEM;
148         if (clnt->cl_metrics == NULL)
149                 goto out_no_stats;
150         clnt->cl_program  = program;
151
152         if (!xprt_bound(clnt->cl_xprt))
153                 clnt->cl_autobind = 1;
154
155         clnt->cl_rtt = &clnt->cl_rtt_default;
156         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
157
158         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
159         if (err < 0)
160                 goto out_no_path;
161
162         auth = rpcauth_create(flavor, clnt);
163         if (IS_ERR(auth)) {
164                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
165                                 flavor);
166                 err = PTR_ERR(auth);
167                 goto out_no_auth;
168         }
169
170         /* save the nodename */
171         clnt->cl_nodelen = strlen(utsname()->nodename);
172         if (clnt->cl_nodelen > UNX_MAXNODENAME)
173                 clnt->cl_nodelen = UNX_MAXNODENAME;
174         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
175         return clnt;
176
177 out_no_auth:
178         if (!IS_ERR(clnt->cl_dentry)) {
179                 rpc_rmdir(clnt->cl_dentry);
180                 rpc_put_mount();
181         }
182 out_no_path:
183         rpc_free_iostats(clnt->cl_metrics);
184 out_no_stats:
185         if (clnt->cl_server != clnt->cl_inline_name)
186                 kfree(clnt->cl_server);
187         kfree(clnt);
188 out_err:
189         xprt_put(xprt);
190 out_no_xprt:
191         return ERR_PTR(err);
192 }
193
194 /*
195  * rpc_create - create an RPC client and transport with one call
196  * @args: rpc_clnt create argument structure
197  *
198  * Creates and initializes an RPC transport and an RPC client.
199  *
200  * It can ping the server in order to determine if it is up, and to see if
201  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
202  * this behavior so asynchronous tasks can also use rpc_create.
203  */
204 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
205 {
206         struct rpc_xprt *xprt;
207         struct rpc_clnt *clnt;
208
209         xprt = xprt_create_transport(args->protocol, args->address,
210                                         args->addrsize, args->timeout);
211         if (IS_ERR(xprt))
212                 return (struct rpc_clnt *)xprt;
213
214         /*
215          * By default, kernel RPC client connects from a reserved port.
216          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
217          * but it is always enabled for rpciod, which handles the connect
218          * operation.
219          */
220         xprt->resvport = 1;
221         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
222                 xprt->resvport = 0;
223
224         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
225                         args->program->name, args->servername, xprt);
226
227         clnt = rpc_new_client(xprt, args->servername, args->program,
228                                 args->version, args->authflavor);
229         if (IS_ERR(clnt))
230                 return clnt;
231
232         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
233                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
234                 if (err != 0) {
235                         rpc_shutdown_client(clnt);
236                         return ERR_PTR(err);
237                 }
238         }
239
240         clnt->cl_softrtry = 1;
241         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
242                 clnt->cl_softrtry = 0;
243
244         if (args->flags & RPC_CLNT_CREATE_INTR)
245                 clnt->cl_intr = 1;
246         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
247                 clnt->cl_autobind = 1;
248         if (args->flags & RPC_CLNT_CREATE_ONESHOT)
249                 clnt->cl_oneshot = 1;
250         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
251                 clnt->cl_discrtry = 1;
252
253         return clnt;
254 }
255 EXPORT_SYMBOL_GPL(rpc_create);
256
257 /*
258  * This function clones the RPC client structure. It allows us to share the
259  * same transport while varying parameters such as the authentication
260  * flavour.
261  */
262 struct rpc_clnt *
263 rpc_clone_client(struct rpc_clnt *clnt)
264 {
265         struct rpc_clnt *new;
266         int err = -ENOMEM;
267
268         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
269         if (!new)
270                 goto out_no_clnt;
271         atomic_set(&new->cl_count, 1);
272         atomic_set(&new->cl_users, 0);
273         new->cl_metrics = rpc_alloc_iostats(clnt);
274         if (new->cl_metrics == NULL)
275                 goto out_no_stats;
276         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
277         if (err != 0)
278                 goto out_no_path;
279         new->cl_parent = clnt;
280         atomic_inc(&clnt->cl_count);
281         new->cl_xprt = xprt_get(clnt->cl_xprt);
282         /* Turn off autobind on clones */
283         new->cl_autobind = 0;
284         new->cl_oneshot = 0;
285         new->cl_dead = 0;
286         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
287         if (new->cl_auth)
288                 atomic_inc(&new->cl_auth->au_count);
289         return new;
290 out_no_path:
291         rpc_free_iostats(new->cl_metrics);
292 out_no_stats:
293         kfree(new);
294 out_no_clnt:
295         dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
296         return ERR_PTR(err);
297 }
298
299 /*
300  * Properly shut down an RPC client, terminating all outstanding
301  * requests. Note that we must be certain that cl_oneshot and
302  * cl_dead are cleared, or else the client would be destroyed
303  * when the last task releases it.
304  */
305 int
306 rpc_shutdown_client(struct rpc_clnt *clnt)
307 {
308         dprintk("RPC:       shutting down %s client for %s, tasks=%d\n",
309                         clnt->cl_protname, clnt->cl_server,
310                         atomic_read(&clnt->cl_users));
311
312         while (atomic_read(&clnt->cl_users) > 0) {
313                 /* Don't let rpc_release_client destroy us */
314                 clnt->cl_oneshot = 0;
315                 clnt->cl_dead = 0;
316                 rpc_killall_tasks(clnt);
317                 wait_event_timeout(destroy_wait,
318                         !atomic_read(&clnt->cl_users), 1*HZ);
319         }
320
321         if (atomic_read(&clnt->cl_users) < 0) {
322                 printk(KERN_ERR "RPC: rpc_shutdown_client clnt %p tasks=%d\n",
323                                 clnt, atomic_read(&clnt->cl_users));
324 #ifdef RPC_DEBUG
325                 rpc_show_tasks();
326 #endif
327                 BUG();
328         }
329
330         return rpc_destroy_client(clnt);
331 }
332
333 /*
334  * Delete an RPC client
335  */
336 int
337 rpc_destroy_client(struct rpc_clnt *clnt)
338 {
339         if (!atomic_dec_and_test(&clnt->cl_count))
340                 return 1;
341         BUG_ON(atomic_read(&clnt->cl_users) != 0);
342
343         dprintk("RPC:       destroying %s client for %s\n",
344                         clnt->cl_protname, clnt->cl_server);
345         if (clnt->cl_auth) {
346                 rpcauth_destroy(clnt->cl_auth);
347                 clnt->cl_auth = NULL;
348         }
349         if (!IS_ERR(clnt->cl_dentry)) {
350                 rpc_rmdir(clnt->cl_dentry);
351                 rpc_put_mount();
352         }
353         if (clnt->cl_parent != clnt) {
354                 rpc_destroy_client(clnt->cl_parent);
355                 goto out_free;
356         }
357         if (clnt->cl_server != clnt->cl_inline_name)
358                 kfree(clnt->cl_server);
359 out_free:
360         rpc_free_iostats(clnt->cl_metrics);
361         clnt->cl_metrics = NULL;
362         xprt_put(clnt->cl_xprt);
363         kfree(clnt);
364         return 0;
365 }
366
367 /*
368  * Release an RPC client
369  */
370 void
371 rpc_release_client(struct rpc_clnt *clnt)
372 {
373         dprintk("RPC:       rpc_release_client(%p, %d)\n",
374                         clnt, atomic_read(&clnt->cl_users));
375
376         if (!atomic_dec_and_test(&clnt->cl_users))
377                 return;
378         wake_up(&destroy_wait);
379         if (clnt->cl_oneshot || clnt->cl_dead)
380                 rpc_destroy_client(clnt);
381 }
382
383 /**
384  * rpc_bind_new_program - bind a new RPC program to an existing client
385  * @old - old rpc_client
386  * @program - rpc program to set
387  * @vers - rpc program version
388  *
389  * Clones the rpc client and sets up a new RPC program. This is mainly
390  * of use for enabling different RPC programs to share the same transport.
391  * The Sun NFSv2/v3 ACL protocol can do this.
392  */
393 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
394                                       struct rpc_program *program,
395                                       int vers)
396 {
397         struct rpc_clnt *clnt;
398         struct rpc_version *version;
399         int err;
400
401         BUG_ON(vers >= program->nrvers || !program->version[vers]);
402         version = program->version[vers];
403         clnt = rpc_clone_client(old);
404         if (IS_ERR(clnt))
405                 goto out;
406         clnt->cl_procinfo = version->procs;
407         clnt->cl_maxproc  = version->nrprocs;
408         clnt->cl_protname = program->name;
409         clnt->cl_prog     = program->number;
410         clnt->cl_vers     = version->number;
411         clnt->cl_stats    = program->stats;
412         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
413         if (err != 0) {
414                 rpc_shutdown_client(clnt);
415                 clnt = ERR_PTR(err);
416         }
417 out:
418         return clnt;
419 }
420
421 /*
422  * Default callback for async RPC calls
423  */
424 static void
425 rpc_default_callback(struct rpc_task *task, void *data)
426 {
427 }
428
429 static const struct rpc_call_ops rpc_default_ops = {
430         .rpc_call_done = rpc_default_callback,
431 };
432
433 /*
434  *      Export the signal mask handling for synchronous code that
435  *      sleeps on RPC calls
436  */
437 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
438
439 static void rpc_save_sigmask(sigset_t *oldset, int intr)
440 {
441         unsigned long   sigallow = sigmask(SIGKILL);
442         sigset_t sigmask;
443
444         /* Block all signals except those listed in sigallow */
445         if (intr)
446                 sigallow |= RPC_INTR_SIGNALS;
447         siginitsetinv(&sigmask, sigallow);
448         sigprocmask(SIG_BLOCK, &sigmask, oldset);
449 }
450
451 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
452 {
453         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
454 }
455
456 static inline void rpc_restore_sigmask(sigset_t *oldset)
457 {
458         sigprocmask(SIG_SETMASK, oldset, NULL);
459 }
460
461 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
462 {
463         rpc_save_sigmask(oldset, clnt->cl_intr);
464 }
465
466 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
467 {
468         rpc_restore_sigmask(oldset);
469 }
470
471 /*
472  * New rpc_call implementation
473  */
474 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
475 {
476         struct rpc_task *task;
477         sigset_t        oldset;
478         int             status;
479
480         /* If this client is slain all further I/O fails */
481         if (clnt->cl_dead)
482                 return -EIO;
483
484         BUG_ON(flags & RPC_TASK_ASYNC);
485
486         task = rpc_new_task(clnt, flags, &rpc_default_ops, NULL);
487         if (task == NULL)
488                 return -ENOMEM;
489
490         /* Mask signals on RPC calls _and_ GSS_AUTH upcalls */
491         rpc_task_sigmask(task, &oldset);
492
493         /* Set up the call info struct and execute the task */
494         rpc_call_setup(task, msg, 0);
495         if (task->tk_status == 0) {
496                 atomic_inc(&task->tk_count);
497                 rpc_execute(task);
498         }
499         status = task->tk_status;
500         rpc_put_task(task);
501         rpc_restore_sigmask(&oldset);
502         return status;
503 }
504
505 /*
506  * New rpc_call implementation
507  */
508 int
509 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
510                const struct rpc_call_ops *tk_ops, void *data)
511 {
512         struct rpc_task *task;
513         sigset_t        oldset;
514         int             status;
515
516         /* If this client is slain all further I/O fails */
517         status = -EIO;
518         if (clnt->cl_dead)
519                 goto out_release;
520
521         flags |= RPC_TASK_ASYNC;
522
523         /* Create/initialize a new RPC task */
524         status = -ENOMEM;
525         if (!(task = rpc_new_task(clnt, flags, tk_ops, data)))
526                 goto out_release;
527
528         /* Mask signals on GSS_AUTH upcalls */
529         rpc_task_sigmask(task, &oldset);
530
531         rpc_call_setup(task, msg, 0);
532
533         /* Set up the call info struct and execute the task */
534         status = task->tk_status;
535         if (status == 0)
536                 rpc_execute(task);
537         else
538                 rpc_put_task(task);
539
540         rpc_restore_sigmask(&oldset);
541         return status;
542 out_release:
543         rpc_release_calldata(tk_ops, data);
544         return status;
545 }
546
547
548 void
549 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
550 {
551         task->tk_msg   = *msg;
552         task->tk_flags |= flags;
553         /* Bind the user cred */
554         if (task->tk_msg.rpc_cred != NULL)
555                 rpcauth_holdcred(task);
556         else
557                 rpcauth_bindcred(task);
558
559         if (task->tk_status == 0)
560                 task->tk_action = call_start;
561         else
562                 task->tk_action = rpc_exit_task;
563 }
564
565 /**
566  * rpc_peeraddr - extract remote peer address from clnt's xprt
567  * @clnt: RPC client structure
568  * @buf: target buffer
569  * @size: length of target buffer
570  *
571  * Returns the number of bytes that are actually in the stored address.
572  */
573 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
574 {
575         size_t bytes;
576         struct rpc_xprt *xprt = clnt->cl_xprt;
577
578         bytes = sizeof(xprt->addr);
579         if (bytes > bufsize)
580                 bytes = bufsize;
581         memcpy(buf, &clnt->cl_xprt->addr, bytes);
582         return xprt->addrlen;
583 }
584 EXPORT_SYMBOL_GPL(rpc_peeraddr);
585
586 /**
587  * rpc_peeraddr2str - return remote peer address in printable format
588  * @clnt: RPC client structure
589  * @format: address format
590  *
591  */
592 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
593 {
594         struct rpc_xprt *xprt = clnt->cl_xprt;
595
596         if (xprt->address_strings[format] != NULL)
597                 return xprt->address_strings[format];
598         else
599                 return "unprintable";
600 }
601 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
602
603 void
604 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
605 {
606         struct rpc_xprt *xprt = clnt->cl_xprt;
607         if (xprt->ops->set_buffer_size)
608                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
609 }
610
611 /*
612  * Return size of largest payload RPC client can support, in bytes
613  *
614  * For stream transports, this is one RPC record fragment (see RFC
615  * 1831), as we don't support multi-record requests yet.  For datagram
616  * transports, this is the size of an IP packet minus the IP, UDP, and
617  * RPC header sizes.
618  */
619 size_t rpc_max_payload(struct rpc_clnt *clnt)
620 {
621         return clnt->cl_xprt->max_payload;
622 }
623 EXPORT_SYMBOL_GPL(rpc_max_payload);
624
625 /**
626  * rpc_force_rebind - force transport to check that remote port is unchanged
627  * @clnt: client to rebind
628  *
629  */
630 void rpc_force_rebind(struct rpc_clnt *clnt)
631 {
632         if (clnt->cl_autobind)
633                 xprt_clear_bound(clnt->cl_xprt);
634 }
635 EXPORT_SYMBOL_GPL(rpc_force_rebind);
636
637 /*
638  * Restart an (async) RPC call. Usually called from within the
639  * exit handler.
640  */
641 void
642 rpc_restart_call(struct rpc_task *task)
643 {
644         if (RPC_ASSASSINATED(task))
645                 return;
646
647         task->tk_action = call_start;
648 }
649
650 /*
651  * 0.  Initial state
652  *
653  *     Other FSM states can be visited zero or more times, but
654  *     this state is visited exactly once for each RPC.
655  */
656 static void
657 call_start(struct rpc_task *task)
658 {
659         struct rpc_clnt *clnt = task->tk_client;
660
661         dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
662                         clnt->cl_protname, clnt->cl_vers,
663                         task->tk_msg.rpc_proc->p_proc,
664                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
665
666         /* Increment call count */
667         task->tk_msg.rpc_proc->p_count++;
668         clnt->cl_stats->rpccnt++;
669         task->tk_action = call_reserve;
670 }
671
672 /*
673  * 1.   Reserve an RPC call slot
674  */
675 static void
676 call_reserve(struct rpc_task *task)
677 {
678         dprint_status(task);
679
680         if (!rpcauth_uptodatecred(task)) {
681                 task->tk_action = call_refresh;
682                 return;
683         }
684
685         task->tk_status  = 0;
686         task->tk_action  = call_reserveresult;
687         xprt_reserve(task);
688 }
689
690 /*
691  * 1b.  Grok the result of xprt_reserve()
692  */
693 static void
694 call_reserveresult(struct rpc_task *task)
695 {
696         int status = task->tk_status;
697
698         dprint_status(task);
699
700         /*
701          * After a call to xprt_reserve(), we must have either
702          * a request slot or else an error status.
703          */
704         task->tk_status = 0;
705         if (status >= 0) {
706                 if (task->tk_rqstp) {
707                         task->tk_action = call_allocate;
708                         return;
709                 }
710
711                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
712                                 __FUNCTION__, status);
713                 rpc_exit(task, -EIO);
714                 return;
715         }
716
717         /*
718          * Even though there was an error, we may have acquired
719          * a request slot somehow.  Make sure not to leak it.
720          */
721         if (task->tk_rqstp) {
722                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
723                                 __FUNCTION__, status);
724                 xprt_release(task);
725         }
726
727         switch (status) {
728         case -EAGAIN:   /* woken up; retry */
729                 task->tk_action = call_reserve;
730                 return;
731         case -EIO:      /* probably a shutdown */
732                 break;
733         default:
734                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
735                                 __FUNCTION__, status);
736                 break;
737         }
738         rpc_exit(task, status);
739 }
740
741 /*
742  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
743  *      (Note: buffer memory is freed in xprt_release).
744  */
745 static void
746 call_allocate(struct rpc_task *task)
747 {
748         unsigned int slack = task->tk_auth->au_cslack;
749         struct rpc_rqst *req = task->tk_rqstp;
750         struct rpc_xprt *xprt = task->tk_xprt;
751         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
752
753         dprint_status(task);
754
755         task->tk_status = 0;
756         task->tk_action = call_bind;
757
758         if (req->rq_buffer)
759                 return;
760
761         if (proc->p_proc != 0) {
762                 BUG_ON(proc->p_arglen == 0);
763                 if (proc->p_decode != NULL)
764                         BUG_ON(proc->p_replen == 0);
765         }
766
767         /*
768          * Calculate the size (in quads) of the RPC call
769          * and reply headers, and convert both values
770          * to byte sizes.
771          */
772         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
773         req->rq_callsize <<= 2;
774         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
775         req->rq_rcvsize <<= 2;
776
777         req->rq_buffer = xprt->ops->buf_alloc(task,
778                                         req->rq_callsize + req->rq_rcvsize);
779         if (req->rq_buffer != NULL)
780                 return;
781
782         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
783
784         if (RPC_IS_ASYNC(task) || !signalled()) {
785                 xprt_release(task);
786                 task->tk_action = call_reserve;
787                 rpc_delay(task, HZ>>4);
788                 return;
789         }
790
791         rpc_exit(task, -ERESTARTSYS);
792 }
793
794 static inline int
795 rpc_task_need_encode(struct rpc_task *task)
796 {
797         return task->tk_rqstp->rq_snd_buf.len == 0;
798 }
799
800 static inline void
801 rpc_task_force_reencode(struct rpc_task *task)
802 {
803         task->tk_rqstp->rq_snd_buf.len = 0;
804 }
805
806 static inline void
807 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
808 {
809         buf->head[0].iov_base = start;
810         buf->head[0].iov_len = len;
811         buf->tail[0].iov_len = 0;
812         buf->page_len = 0;
813         buf->len = 0;
814         buf->buflen = len;
815 }
816
817 /*
818  * 3.   Encode arguments of an RPC call
819  */
820 static void
821 call_encode(struct rpc_task *task)
822 {
823         struct rpc_rqst *req = task->tk_rqstp;
824         kxdrproc_t      encode;
825         __be32          *p;
826
827         dprint_status(task);
828
829         rpc_xdr_buf_init(&req->rq_snd_buf,
830                          req->rq_buffer,
831                          req->rq_callsize);
832         rpc_xdr_buf_init(&req->rq_rcv_buf,
833                          (char *)req->rq_buffer + req->rq_callsize,
834                          req->rq_rcvsize);
835
836         /* Encode header and provided arguments */
837         encode = task->tk_msg.rpc_proc->p_encode;
838         if (!(p = call_header(task))) {
839                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
840                 rpc_exit(task, -EIO);
841                 return;
842         }
843         if (encode == NULL)
844                 return;
845
846         lock_kernel();
847         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
848                         task->tk_msg.rpc_argp);
849         unlock_kernel();
850         if (task->tk_status == -ENOMEM) {
851                 /* XXX: Is this sane? */
852                 rpc_delay(task, 3*HZ);
853                 task->tk_status = -EAGAIN;
854         }
855 }
856
857 /*
858  * 4.   Get the server port number if not yet set
859  */
860 static void
861 call_bind(struct rpc_task *task)
862 {
863         struct rpc_xprt *xprt = task->tk_xprt;
864
865         dprint_status(task);
866
867         task->tk_action = call_connect;
868         if (!xprt_bound(xprt)) {
869                 task->tk_action = call_bind_status;
870                 task->tk_timeout = xprt->bind_timeout;
871                 xprt->ops->rpcbind(task);
872         }
873 }
874
875 /*
876  * 4a.  Sort out bind result
877  */
878 static void
879 call_bind_status(struct rpc_task *task)
880 {
881         int status = -EACCES;
882
883         if (task->tk_status >= 0) {
884                 dprint_status(task);
885                 task->tk_status = 0;
886                 task->tk_action = call_connect;
887                 return;
888         }
889
890         switch (task->tk_status) {
891         case -EACCES:
892                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
893                                 "unavailable\n", task->tk_pid);
894                 rpc_delay(task, 3*HZ);
895                 goto retry_timeout;
896         case -ETIMEDOUT:
897                 dprintk("RPC: %5u rpcbind request timed out\n",
898                                 task->tk_pid);
899                 goto retry_timeout;
900         case -EPFNOSUPPORT:
901                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
902                                 task->tk_pid);
903                 break;
904         case -EPROTONOSUPPORT:
905                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
906                                 task->tk_pid);
907                 task->tk_status = 0;
908                 task->tk_action = call_bind;
909                 return;
910         default:
911                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
912                                 task->tk_pid, -task->tk_status);
913                 status = -EIO;
914         }
915
916         rpc_exit(task, status);
917         return;
918
919 retry_timeout:
920         task->tk_action = call_timeout;
921 }
922
923 /*
924  * 4b.  Connect to the RPC server
925  */
926 static void
927 call_connect(struct rpc_task *task)
928 {
929         struct rpc_xprt *xprt = task->tk_xprt;
930
931         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
932                         task->tk_pid, xprt,
933                         (xprt_connected(xprt) ? "is" : "is not"));
934
935         task->tk_action = call_transmit;
936         if (!xprt_connected(xprt)) {
937                 task->tk_action = call_connect_status;
938                 if (task->tk_status < 0)
939                         return;
940                 xprt_connect(task);
941         }
942 }
943
944 /*
945  * 4c.  Sort out connect result
946  */
947 static void
948 call_connect_status(struct rpc_task *task)
949 {
950         struct rpc_clnt *clnt = task->tk_client;
951         int status = task->tk_status;
952
953         dprint_status(task);
954
955         task->tk_status = 0;
956         if (status >= 0) {
957                 clnt->cl_stats->netreconn++;
958                 task->tk_action = call_transmit;
959                 return;
960         }
961
962         /* Something failed: remote service port may have changed */
963         rpc_force_rebind(clnt);
964
965         switch (status) {
966         case -ENOTCONN:
967         case -EAGAIN:
968                 task->tk_action = call_bind;
969                 if (!RPC_IS_SOFT(task))
970                         return;
971                 /* if soft mounted, test if we've timed out */
972         case -ETIMEDOUT:
973                 task->tk_action = call_timeout;
974                 return;
975         }
976         rpc_exit(task, -EIO);
977 }
978
979 /*
980  * 5.   Transmit the RPC request, and wait for reply
981  */
982 static void
983 call_transmit(struct rpc_task *task)
984 {
985         dprint_status(task);
986
987         task->tk_action = call_status;
988         if (task->tk_status < 0)
989                 return;
990         task->tk_status = xprt_prepare_transmit(task);
991         if (task->tk_status != 0)
992                 return;
993         task->tk_action = call_transmit_status;
994         /* Encode here so that rpcsec_gss can use correct sequence number. */
995         if (rpc_task_need_encode(task)) {
996                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
997                 call_encode(task);
998                 /* Did the encode result in an error condition? */
999                 if (task->tk_status != 0)
1000                         return;
1001         }
1002         xprt_transmit(task);
1003         if (task->tk_status < 0)
1004                 return;
1005         /*
1006          * On success, ensure that we call xprt_end_transmit() before sleeping
1007          * in order to allow access to the socket to other RPC requests.
1008          */
1009         call_transmit_status(task);
1010         if (task->tk_msg.rpc_proc->p_decode != NULL)
1011                 return;
1012         task->tk_action = rpc_exit_task;
1013         rpc_wake_up_task(task);
1014 }
1015
1016 /*
1017  * 5a.  Handle cleanup after a transmission
1018  */
1019 static void
1020 call_transmit_status(struct rpc_task *task)
1021 {
1022         task->tk_action = call_status;
1023         /*
1024          * Special case: if we've been waiting on the socket's write_space()
1025          * callback, then don't call xprt_end_transmit().
1026          */
1027         if (task->tk_status == -EAGAIN)
1028                 return;
1029         xprt_end_transmit(task);
1030         rpc_task_force_reencode(task);
1031 }
1032
1033 /*
1034  * 6.   Sort out the RPC call status
1035  */
1036 static void
1037 call_status(struct rpc_task *task)
1038 {
1039         struct rpc_clnt *clnt = task->tk_client;
1040         struct rpc_rqst *req = task->tk_rqstp;
1041         int             status;
1042
1043         if (req->rq_received > 0 && !req->rq_bytes_sent)
1044                 task->tk_status = req->rq_received;
1045
1046         dprint_status(task);
1047
1048         status = task->tk_status;
1049         if (status >= 0) {
1050                 task->tk_action = call_decode;
1051                 return;
1052         }
1053
1054         task->tk_status = 0;
1055         switch(status) {
1056         case -EHOSTDOWN:
1057         case -EHOSTUNREACH:
1058         case -ENETUNREACH:
1059                 /*
1060                  * Delay any retries for 3 seconds, then handle as if it
1061                  * were a timeout.
1062                  */
1063                 rpc_delay(task, 3*HZ);
1064         case -ETIMEDOUT:
1065                 task->tk_action = call_timeout;
1066                 if (task->tk_client->cl_discrtry)
1067                         xprt_disconnect(task->tk_xprt);
1068                 break;
1069         case -ECONNREFUSED:
1070         case -ENOTCONN:
1071                 rpc_force_rebind(clnt);
1072                 task->tk_action = call_bind;
1073                 break;
1074         case -EAGAIN:
1075                 task->tk_action = call_transmit;
1076                 break;
1077         case -EIO:
1078                 /* shutdown or soft timeout */
1079                 rpc_exit(task, status);
1080                 break;
1081         default:
1082                 printk("%s: RPC call returned error %d\n",
1083                                clnt->cl_protname, -status);
1084                 rpc_exit(task, status);
1085         }
1086 }
1087
1088 /*
1089  * 6a.  Handle RPC timeout
1090  *      We do not release the request slot, so we keep using the
1091  *      same XID for all retransmits.
1092  */
1093 static void
1094 call_timeout(struct rpc_task *task)
1095 {
1096         struct rpc_clnt *clnt = task->tk_client;
1097
1098         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1099                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1100                 goto retry;
1101         }
1102
1103         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1104         task->tk_timeouts++;
1105
1106         if (RPC_IS_SOFT(task)) {
1107                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1108                                 clnt->cl_protname, clnt->cl_server);
1109                 rpc_exit(task, -EIO);
1110                 return;
1111         }
1112
1113         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1114                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1115                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1116                         clnt->cl_protname, clnt->cl_server);
1117         }
1118         rpc_force_rebind(clnt);
1119
1120 retry:
1121         clnt->cl_stats->rpcretrans++;
1122         task->tk_action = call_bind;
1123         task->tk_status = 0;
1124 }
1125
1126 /*
1127  * 7.   Decode the RPC reply
1128  */
1129 static void
1130 call_decode(struct rpc_task *task)
1131 {
1132         struct rpc_clnt *clnt = task->tk_client;
1133         struct rpc_rqst *req = task->tk_rqstp;
1134         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1135         __be32          *p;
1136
1137         dprintk("RPC: %5u call_decode (status %d)\n",
1138                         task->tk_pid, task->tk_status);
1139
1140         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1141                 printk(KERN_NOTICE "%s: server %s OK\n",
1142                         clnt->cl_protname, clnt->cl_server);
1143                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1144         }
1145
1146         if (task->tk_status < 12) {
1147                 if (!RPC_IS_SOFT(task)) {
1148                         task->tk_action = call_bind;
1149                         clnt->cl_stats->rpcretrans++;
1150                         goto out_retry;
1151                 }
1152                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1153                                 clnt->cl_protname, task->tk_status);
1154                 task->tk_action = call_timeout;
1155                 goto out_retry;
1156         }
1157
1158         /*
1159          * Ensure that we see all writes made by xprt_complete_rqst()
1160          * before it changed req->rq_received.
1161          */
1162         smp_rmb();
1163         req->rq_rcv_buf.len = req->rq_private_buf.len;
1164
1165         /* Check that the softirq receive buffer is valid */
1166         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1167                                 sizeof(req->rq_rcv_buf)) != 0);
1168
1169         /* Verify the RPC header */
1170         p = call_verify(task);
1171         if (IS_ERR(p)) {
1172                 if (p == ERR_PTR(-EAGAIN))
1173                         goto out_retry;
1174                 return;
1175         }
1176
1177         task->tk_action = rpc_exit_task;
1178
1179         if (decode) {
1180                 lock_kernel();
1181                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1182                                                       task->tk_msg.rpc_resp);
1183                 unlock_kernel();
1184         }
1185         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1186                         task->tk_status);
1187         return;
1188 out_retry:
1189         req->rq_received = req->rq_private_buf.len = 0;
1190         task->tk_status = 0;
1191         if (task->tk_client->cl_discrtry)
1192                 xprt_disconnect(task->tk_xprt);
1193 }
1194
1195 /*
1196  * 8.   Refresh the credentials if rejected by the server
1197  */
1198 static void
1199 call_refresh(struct rpc_task *task)
1200 {
1201         dprint_status(task);
1202
1203         xprt_release(task);     /* Must do to obtain new XID */
1204         task->tk_action = call_refreshresult;
1205         task->tk_status = 0;
1206         task->tk_client->cl_stats->rpcauthrefresh++;
1207         rpcauth_refreshcred(task);
1208 }
1209
1210 /*
1211  * 8a.  Process the results of a credential refresh
1212  */
1213 static void
1214 call_refreshresult(struct rpc_task *task)
1215 {
1216         int status = task->tk_status;
1217
1218         dprint_status(task);
1219
1220         task->tk_status = 0;
1221         task->tk_action = call_reserve;
1222         if (status >= 0 && rpcauth_uptodatecred(task))
1223                 return;
1224         if (status == -EACCES) {
1225                 rpc_exit(task, -EACCES);
1226                 return;
1227         }
1228         task->tk_action = call_refresh;
1229         if (status != -ETIMEDOUT)
1230                 rpc_delay(task, 3*HZ);
1231         return;
1232 }
1233
1234 /*
1235  * Call header serialization
1236  */
1237 static __be32 *
1238 call_header(struct rpc_task *task)
1239 {
1240         struct rpc_clnt *clnt = task->tk_client;
1241         struct rpc_rqst *req = task->tk_rqstp;
1242         __be32          *p = req->rq_svec[0].iov_base;
1243
1244         /* FIXME: check buffer size? */
1245
1246         p = xprt_skip_transport_header(task->tk_xprt, p);
1247         *p++ = req->rq_xid;             /* XID */
1248         *p++ = htonl(RPC_CALL);         /* CALL */
1249         *p++ = htonl(RPC_VERSION);      /* RPC version */
1250         *p++ = htonl(clnt->cl_prog);    /* program number */
1251         *p++ = htonl(clnt->cl_vers);    /* program version */
1252         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1253         p = rpcauth_marshcred(task, p);
1254         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1255         return p;
1256 }
1257
1258 /*
1259  * Reply header verification
1260  */
1261 static __be32 *
1262 call_verify(struct rpc_task *task)
1263 {
1264         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1265         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1266         __be32  *p = iov->iov_base;
1267         u32 n;
1268         int error = -EACCES;
1269
1270         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1271                 /* RFC-1014 says that the representation of XDR data must be a
1272                  * multiple of four bytes
1273                  * - if it isn't pointer subtraction in the NFS client may give
1274                  *   undefined results
1275                  */
1276                 printk(KERN_WARNING
1277                        "call_verify: XDR representation not a multiple of"
1278                        " 4 bytes: 0x%x\n", task->tk_rqstp->rq_rcv_buf.len);
1279                 goto out_eio;
1280         }
1281         if ((len -= 3) < 0)
1282                 goto out_overflow;
1283         p += 1; /* skip XID */
1284
1285         if ((n = ntohl(*p++)) != RPC_REPLY) {
1286                 printk(KERN_WARNING "call_verify: not an RPC reply: %x\n", n);
1287                 goto out_garbage;
1288         }
1289         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1290                 if (--len < 0)
1291                         goto out_overflow;
1292                 switch ((n = ntohl(*p++))) {
1293                         case RPC_AUTH_ERROR:
1294                                 break;
1295                         case RPC_MISMATCH:
1296                                 dprintk("RPC: %5u %s: RPC call version "
1297                                                 "mismatch!\n",
1298                                                 task->tk_pid, __FUNCTION__);
1299                                 error = -EPROTONOSUPPORT;
1300                                 goto out_err;
1301                         default:
1302                                 dprintk("RPC: %5u %s: RPC call rejected, "
1303                                                 "unknown error: %x\n",
1304                                                 task->tk_pid, __FUNCTION__, n);
1305                                 goto out_eio;
1306                 }
1307                 if (--len < 0)
1308                         goto out_overflow;
1309                 switch ((n = ntohl(*p++))) {
1310                 case RPC_AUTH_REJECTEDCRED:
1311                 case RPC_AUTH_REJECTEDVERF:
1312                 case RPCSEC_GSS_CREDPROBLEM:
1313                 case RPCSEC_GSS_CTXPROBLEM:
1314                         if (!task->tk_cred_retry)
1315                                 break;
1316                         task->tk_cred_retry--;
1317                         dprintk("RPC: %5u %s: retry stale creds\n",
1318                                         task->tk_pid, __FUNCTION__);
1319                         rpcauth_invalcred(task);
1320                         task->tk_action = call_refresh;
1321                         goto out_retry;
1322                 case RPC_AUTH_BADCRED:
1323                 case RPC_AUTH_BADVERF:
1324                         /* possibly garbled cred/verf? */
1325                         if (!task->tk_garb_retry)
1326                                 break;
1327                         task->tk_garb_retry--;
1328                         dprintk("RPC: %5u %s: retry garbled creds\n",
1329                                         task->tk_pid, __FUNCTION__);
1330                         task->tk_action = call_bind;
1331                         goto out_retry;
1332                 case RPC_AUTH_TOOWEAK:
1333                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1334                                "authentication.\n", task->tk_client->cl_server);
1335                         break;
1336                 default:
1337                         printk(KERN_WARNING "call_verify: unknown auth error: %x\n", n);
1338                         error = -EIO;
1339                 }
1340                 dprintk("RPC: %5u %s: call rejected %d\n",
1341                                 task->tk_pid, __FUNCTION__, n);
1342                 goto out_err;
1343         }
1344         if (!(p = rpcauth_checkverf(task, p))) {
1345                 printk(KERN_WARNING "call_verify: auth check failed\n");
1346                 goto out_garbage;               /* bad verifier, retry */
1347         }
1348         len = p - (__be32 *)iov->iov_base - 1;
1349         if (len < 0)
1350                 goto out_overflow;
1351         switch ((n = ntohl(*p++))) {
1352         case RPC_SUCCESS:
1353                 return p;
1354         case RPC_PROG_UNAVAIL:
1355                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1356                                 task->tk_pid, __FUNCTION__,
1357                                 (unsigned int)task->tk_client->cl_prog,
1358                                 task->tk_client->cl_server);
1359                 error = -EPFNOSUPPORT;
1360                 goto out_err;
1361         case RPC_PROG_MISMATCH:
1362                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1363                                 "server %s\n", task->tk_pid, __FUNCTION__,
1364                                 (unsigned int)task->tk_client->cl_prog,
1365                                 (unsigned int)task->tk_client->cl_vers,
1366                                 task->tk_client->cl_server);
1367                 error = -EPROTONOSUPPORT;
1368                 goto out_err;
1369         case RPC_PROC_UNAVAIL:
1370                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1371                                 "version %u on server %s\n",
1372                                 task->tk_pid, __FUNCTION__,
1373                                 task->tk_msg.rpc_proc,
1374                                 task->tk_client->cl_prog,
1375                                 task->tk_client->cl_vers,
1376                                 task->tk_client->cl_server);
1377                 error = -EOPNOTSUPP;
1378                 goto out_err;
1379         case RPC_GARBAGE_ARGS:
1380                 dprintk("RPC: %5u %s: server saw garbage\n",
1381                                 task->tk_pid, __FUNCTION__);
1382                 break;                  /* retry */
1383         default:
1384                 printk(KERN_WARNING "call_verify: server accept status: %x\n", n);
1385                 /* Also retry */
1386         }
1387
1388 out_garbage:
1389         task->tk_client->cl_stats->rpcgarbage++;
1390         if (task->tk_garb_retry) {
1391                 task->tk_garb_retry--;
1392                 dprintk("RPC: %5u %s: retrying\n",
1393                                 task->tk_pid, __FUNCTION__);
1394                 task->tk_action = call_bind;
1395 out_retry:
1396                 return ERR_PTR(-EAGAIN);
1397         }
1398         printk(KERN_WARNING "RPC %s: retry failed, exit EIO\n", __FUNCTION__);
1399 out_eio:
1400         error = -EIO;
1401 out_err:
1402         rpc_exit(task, error);
1403         return ERR_PTR(error);
1404 out_overflow:
1405         printk(KERN_WARNING "RPC %s: server reply was truncated.\n", __FUNCTION__);
1406         goto out_garbage;
1407 }
1408
1409 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1410 {
1411         return 0;
1412 }
1413
1414 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1415 {
1416         return 0;
1417 }
1418
1419 static struct rpc_procinfo rpcproc_null = {
1420         .p_encode = rpcproc_encode_null,
1421         .p_decode = rpcproc_decode_null,
1422 };
1423
1424 int rpc_ping(struct rpc_clnt *clnt, int flags)
1425 {
1426         struct rpc_message msg = {
1427                 .rpc_proc = &rpcproc_null,
1428         };
1429         int err;
1430         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1431         err = rpc_call_sync(clnt, &msg, flags);
1432         put_rpccred(msg.rpc_cred);
1433         return err;
1434 }