Pull osi into release branch
[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 /*
48  * All RPC clients are linked into this list
49  */
50 static LIST_HEAD(all_clients);
51 static DEFINE_SPINLOCK(rpc_client_lock);
52
53 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
54
55
56 static void     call_start(struct rpc_task *task);
57 static void     call_reserve(struct rpc_task *task);
58 static void     call_reserveresult(struct rpc_task *task);
59 static void     call_allocate(struct rpc_task *task);
60 static void     call_encode(struct rpc_task *task);
61 static void     call_decode(struct rpc_task *task);
62 static void     call_bind(struct rpc_task *task);
63 static void     call_bind_status(struct rpc_task *task);
64 static void     call_transmit(struct rpc_task *task);
65 static void     call_status(struct rpc_task *task);
66 static void     call_transmit_status(struct rpc_task *task);
67 static void     call_refresh(struct rpc_task *task);
68 static void     call_refreshresult(struct rpc_task *task);
69 static void     call_timeout(struct rpc_task *task);
70 static void     call_connect(struct rpc_task *task);
71 static void     call_connect_status(struct rpc_task *task);
72 static __be32 * call_header(struct rpc_task *task);
73 static __be32 * call_verify(struct rpc_task *task);
74
75 static int      rpc_ping(struct rpc_clnt *clnt, int flags);
76
77 static void rpc_register_client(struct rpc_clnt *clnt)
78 {
79         spin_lock(&rpc_client_lock);
80         list_add(&clnt->cl_clients, &all_clients);
81         spin_unlock(&rpc_client_lock);
82 }
83
84 static void rpc_unregister_client(struct rpc_clnt *clnt)
85 {
86         spin_lock(&rpc_client_lock);
87         list_del(&clnt->cl_clients);
88         spin_unlock(&rpc_client_lock);
89 }
90
91 static int
92 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
93 {
94         static uint32_t clntid;
95         int error;
96
97         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
98         clnt->cl_dentry = ERR_PTR(-ENOENT);
99         if (dir_name == NULL)
100                 return 0;
101
102         clnt->cl_vfsmnt = rpc_get_mount();
103         if (IS_ERR(clnt->cl_vfsmnt))
104                 return PTR_ERR(clnt->cl_vfsmnt);
105
106         for (;;) {
107                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
108                                 "%s/clnt%x", dir_name,
109                                 (unsigned int)clntid++);
110                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
111                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
112                 if (!IS_ERR(clnt->cl_dentry))
113                         return 0;
114                 error = PTR_ERR(clnt->cl_dentry);
115                 if (error != -EEXIST) {
116                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
117                                         clnt->cl_pathname, error);
118                         rpc_put_mount();
119                         return error;
120                 }
121         }
122 }
123
124 static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
125 {
126         struct rpc_version      *version;
127         struct rpc_clnt         *clnt = NULL;
128         struct rpc_auth         *auth;
129         int err;
130         int len;
131
132         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
133                         program->name, servname, xprt);
134
135         err = rpciod_up();
136         if (err)
137                 goto out_no_rpciod;
138         err = -EINVAL;
139         if (!xprt)
140                 goto out_no_xprt;
141         if (vers >= program->nrvers || !(version = program->version[vers]))
142                 goto out_err;
143
144         err = -ENOMEM;
145         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
146         if (!clnt)
147                 goto out_err;
148         clnt->cl_parent = clnt;
149
150         clnt->cl_server = clnt->cl_inline_name;
151         len = strlen(servname) + 1;
152         if (len > sizeof(clnt->cl_inline_name)) {
153                 char *buf = kmalloc(len, GFP_KERNEL);
154                 if (buf != 0)
155                         clnt->cl_server = buf;
156                 else
157                         len = sizeof(clnt->cl_inline_name);
158         }
159         strlcpy(clnt->cl_server, servname, len);
160
161         clnt->cl_xprt     = xprt;
162         clnt->cl_procinfo = version->procs;
163         clnt->cl_maxproc  = version->nrprocs;
164         clnt->cl_protname = program->name;
165         clnt->cl_prog     = program->number;
166         clnt->cl_vers     = version->number;
167         clnt->cl_stats    = program->stats;
168         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
169         err = -ENOMEM;
170         if (clnt->cl_metrics == NULL)
171                 goto out_no_stats;
172         clnt->cl_program  = program;
173         INIT_LIST_HEAD(&clnt->cl_tasks);
174         spin_lock_init(&clnt->cl_lock);
175
176         if (!xprt_bound(clnt->cl_xprt))
177                 clnt->cl_autobind = 1;
178
179         clnt->cl_rtt = &clnt->cl_rtt_default;
180         rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
181
182         kref_init(&clnt->cl_kref);
183
184         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
185         if (err < 0)
186                 goto out_no_path;
187
188         auth = rpcauth_create(flavor, clnt);
189         if (IS_ERR(auth)) {
190                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
191                                 flavor);
192                 err = PTR_ERR(auth);
193                 goto out_no_auth;
194         }
195
196         /* save the nodename */
197         clnt->cl_nodelen = strlen(utsname()->nodename);
198         if (clnt->cl_nodelen > UNX_MAXNODENAME)
199                 clnt->cl_nodelen = UNX_MAXNODENAME;
200         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
201         rpc_register_client(clnt);
202         return clnt;
203
204 out_no_auth:
205         if (!IS_ERR(clnt->cl_dentry)) {
206                 rpc_rmdir(clnt->cl_dentry);
207                 rpc_put_mount();
208         }
209 out_no_path:
210         rpc_free_iostats(clnt->cl_metrics);
211 out_no_stats:
212         if (clnt->cl_server != clnt->cl_inline_name)
213                 kfree(clnt->cl_server);
214         kfree(clnt);
215 out_err:
216         xprt_put(xprt);
217 out_no_xprt:
218         rpciod_down();
219 out_no_rpciod:
220         return ERR_PTR(err);
221 }
222
223 /*
224  * rpc_create - create an RPC client and transport with one call
225  * @args: rpc_clnt create argument structure
226  *
227  * Creates and initializes an RPC transport and an RPC client.
228  *
229  * It can ping the server in order to determine if it is up, and to see if
230  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
231  * this behavior so asynchronous tasks can also use rpc_create.
232  */
233 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
234 {
235         struct rpc_xprt *xprt;
236         struct rpc_clnt *clnt;
237         struct rpc_xprtsock_create xprtargs = {
238                 .proto = args->protocol,
239                 .srcaddr = args->saddress,
240                 .dstaddr = args->address,
241                 .addrlen = args->addrsize,
242                 .timeout = args->timeout
243         };
244         char servername[20];
245
246         xprt = xprt_create_transport(&xprtargs);
247         if (IS_ERR(xprt))
248                 return (struct rpc_clnt *)xprt;
249
250         /*
251          * If the caller chooses not to specify a hostname, whip
252          * up a string representation of the passed-in address.
253          */
254         if (args->servername == NULL) {
255                 struct sockaddr_in *addr =
256                                         (struct sockaddr_in *) &args->address;
257                 snprintf(servername, sizeof(servername), NIPQUAD_FMT,
258                         NIPQUAD(addr->sin_addr.s_addr));
259                 args->servername = servername;
260         }
261
262         /*
263          * By default, kernel RPC client connects from a reserved port.
264          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
265          * but it is always enabled for rpciod, which handles the connect
266          * operation.
267          */
268         xprt->resvport = 1;
269         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
270                 xprt->resvport = 0;
271
272         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
273                         args->program->name, args->servername, xprt);
274
275         clnt = rpc_new_client(xprt, args->servername, args->program,
276                                 args->version, args->authflavor);
277         if (IS_ERR(clnt))
278                 return clnt;
279
280         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
281                 int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
282                 if (err != 0) {
283                         rpc_shutdown_client(clnt);
284                         return ERR_PTR(err);
285                 }
286         }
287
288         clnt->cl_softrtry = 1;
289         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
290                 clnt->cl_softrtry = 0;
291
292         if (args->flags & RPC_CLNT_CREATE_INTR)
293                 clnt->cl_intr = 1;
294         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
295                 clnt->cl_autobind = 1;
296         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
297                 clnt->cl_discrtry = 1;
298
299         return clnt;
300 }
301 EXPORT_SYMBOL_GPL(rpc_create);
302
303 /*
304  * This function clones the RPC client structure. It allows us to share the
305  * same transport while varying parameters such as the authentication
306  * flavour.
307  */
308 struct rpc_clnt *
309 rpc_clone_client(struct rpc_clnt *clnt)
310 {
311         struct rpc_clnt *new;
312         int err = -ENOMEM;
313
314         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
315         if (!new)
316                 goto out_no_clnt;
317         new->cl_parent = clnt;
318         /* Turn off autobind on clones */
319         new->cl_autobind = 0;
320         INIT_LIST_HEAD(&new->cl_tasks);
321         spin_lock_init(&new->cl_lock);
322         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
323         new->cl_metrics = rpc_alloc_iostats(clnt);
324         if (new->cl_metrics == NULL)
325                 goto out_no_stats;
326         kref_init(&new->cl_kref);
327         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
328         if (err != 0)
329                 goto out_no_path;
330         if (new->cl_auth)
331                 atomic_inc(&new->cl_auth->au_count);
332         xprt_get(clnt->cl_xprt);
333         kref_get(&clnt->cl_kref);
334         rpc_register_client(new);
335         rpciod_up();
336         return new;
337 out_no_path:
338         rpc_free_iostats(new->cl_metrics);
339 out_no_stats:
340         kfree(new);
341 out_no_clnt:
342         dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
343         return ERR_PTR(err);
344 }
345
346 /*
347  * Properly shut down an RPC client, terminating all outstanding
348  * requests.
349  */
350 void rpc_shutdown_client(struct rpc_clnt *clnt)
351 {
352         dprintk("RPC:       shutting down %s client for %s\n",
353                         clnt->cl_protname, clnt->cl_server);
354
355         while (!list_empty(&clnt->cl_tasks)) {
356                 rpc_killall_tasks(clnt);
357                 wait_event_timeout(destroy_wait,
358                         list_empty(&clnt->cl_tasks), 1*HZ);
359         }
360
361         rpc_release_client(clnt);
362 }
363
364 /*
365  * Free an RPC client
366  */
367 static void
368 rpc_free_client(struct kref *kref)
369 {
370         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
371
372         dprintk("RPC:       destroying %s client for %s\n",
373                         clnt->cl_protname, clnt->cl_server);
374         if (!IS_ERR(clnt->cl_dentry)) {
375                 rpc_rmdir(clnt->cl_dentry);
376                 rpc_put_mount();
377         }
378         if (clnt->cl_parent != clnt) {
379                 rpc_release_client(clnt->cl_parent);
380                 goto out_free;
381         }
382         if (clnt->cl_server != clnt->cl_inline_name)
383                 kfree(clnt->cl_server);
384 out_free:
385         rpc_unregister_client(clnt);
386         rpc_free_iostats(clnt->cl_metrics);
387         clnt->cl_metrics = NULL;
388         xprt_put(clnt->cl_xprt);
389         rpciod_down();
390         kfree(clnt);
391 }
392
393 /*
394  * Free an RPC client
395  */
396 static void
397 rpc_free_auth(struct kref *kref)
398 {
399         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
400
401         if (clnt->cl_auth == NULL) {
402                 rpc_free_client(kref);
403                 return;
404         }
405
406         /*
407          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
408          *       release remaining GSS contexts. This mechanism ensures
409          *       that it can do so safely.
410          */
411         kref_init(kref);
412         rpcauth_release(clnt->cl_auth);
413         clnt->cl_auth = NULL;
414         kref_put(kref, rpc_free_client);
415 }
416
417 /*
418  * Release reference to the RPC client
419  */
420 void
421 rpc_release_client(struct rpc_clnt *clnt)
422 {
423         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
424
425         if (list_empty(&clnt->cl_tasks))
426                 wake_up(&destroy_wait);
427         kref_put(&clnt->cl_kref, rpc_free_auth);
428 }
429
430 /**
431  * rpc_bind_new_program - bind a new RPC program to an existing client
432  * @old - old rpc_client
433  * @program - rpc program to set
434  * @vers - rpc program version
435  *
436  * Clones the rpc client and sets up a new RPC program. This is mainly
437  * of use for enabling different RPC programs to share the same transport.
438  * The Sun NFSv2/v3 ACL protocol can do this.
439  */
440 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
441                                       struct rpc_program *program,
442                                       int vers)
443 {
444         struct rpc_clnt *clnt;
445         struct rpc_version *version;
446         int err;
447
448         BUG_ON(vers >= program->nrvers || !program->version[vers]);
449         version = program->version[vers];
450         clnt = rpc_clone_client(old);
451         if (IS_ERR(clnt))
452                 goto out;
453         clnt->cl_procinfo = version->procs;
454         clnt->cl_maxproc  = version->nrprocs;
455         clnt->cl_protname = program->name;
456         clnt->cl_prog     = program->number;
457         clnt->cl_vers     = version->number;
458         clnt->cl_stats    = program->stats;
459         err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
460         if (err != 0) {
461                 rpc_shutdown_client(clnt);
462                 clnt = ERR_PTR(err);
463         }
464 out:
465         return clnt;
466 }
467
468 /*
469  * Default callback for async RPC calls
470  */
471 static void
472 rpc_default_callback(struct rpc_task *task, void *data)
473 {
474 }
475
476 static const struct rpc_call_ops rpc_default_ops = {
477         .rpc_call_done = rpc_default_callback,
478 };
479
480 /*
481  *      Export the signal mask handling for synchronous code that
482  *      sleeps on RPC calls
483  */
484 #define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
485
486 static void rpc_save_sigmask(sigset_t *oldset, int intr)
487 {
488         unsigned long   sigallow = sigmask(SIGKILL);
489         sigset_t sigmask;
490
491         /* Block all signals except those listed in sigallow */
492         if (intr)
493                 sigallow |= RPC_INTR_SIGNALS;
494         siginitsetinv(&sigmask, sigallow);
495         sigprocmask(SIG_BLOCK, &sigmask, oldset);
496 }
497
498 static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
499 {
500         rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
501 }
502
503 static inline void rpc_restore_sigmask(sigset_t *oldset)
504 {
505         sigprocmask(SIG_SETMASK, oldset, NULL);
506 }
507
508 void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
509 {
510         rpc_save_sigmask(oldset, clnt->cl_intr);
511 }
512
513 void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
514 {
515         rpc_restore_sigmask(oldset);
516 }
517
518 static
519 struct rpc_task *rpc_do_run_task(struct rpc_clnt *clnt,
520                 struct rpc_message *msg,
521                 int flags,
522                 const struct rpc_call_ops *ops,
523                 void *data)
524 {
525         struct rpc_task *task, *ret;
526         sigset_t oldset;
527
528         task = rpc_new_task(clnt, flags, ops, data);
529         if (task == NULL) {
530                 rpc_release_calldata(ops, data);
531                 return ERR_PTR(-ENOMEM);
532         }
533
534         /* Mask signals on synchronous RPC calls and RPCSEC_GSS upcalls */
535         rpc_task_sigmask(task, &oldset);
536         if (msg != NULL) {
537                 rpc_call_setup(task, msg, 0);
538                 if (task->tk_status != 0) {
539                         ret = ERR_PTR(task->tk_status);
540                         rpc_put_task(task);
541                         goto out;
542                 }
543         }
544         atomic_inc(&task->tk_count);
545         rpc_execute(task);
546         ret = task;
547 out:
548         rpc_restore_sigmask(&oldset);
549         return ret;
550 }
551
552 /**
553  * rpc_call_sync - Perform a synchronous RPC call
554  * @clnt: pointer to RPC client
555  * @msg: RPC call parameters
556  * @flags: RPC call flags
557  */
558 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
559 {
560         struct rpc_task *task;
561         int status;
562
563         BUG_ON(flags & RPC_TASK_ASYNC);
564
565         task = rpc_do_run_task(clnt, msg, flags, &rpc_default_ops, NULL);
566         if (IS_ERR(task))
567                 return PTR_ERR(task);
568         status = task->tk_status;
569         rpc_put_task(task);
570         return status;
571 }
572
573 /**
574  * rpc_call_async - Perform an asynchronous RPC call
575  * @clnt: pointer to RPC client
576  * @msg: RPC call parameters
577  * @flags: RPC call flags
578  * @ops: RPC call ops
579  * @data: user call data
580  */
581 int
582 rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
583                const struct rpc_call_ops *tk_ops, void *data)
584 {
585         struct rpc_task *task;
586
587         task = rpc_do_run_task(clnt, msg, flags|RPC_TASK_ASYNC, tk_ops, data);
588         if (IS_ERR(task))
589                 return PTR_ERR(task);
590         rpc_put_task(task);
591         return 0;
592 }
593
594 /**
595  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
596  * @clnt: pointer to RPC client
597  * @flags: RPC flags
598  * @ops: RPC call ops
599  * @data: user call data
600  */
601 struct rpc_task *rpc_run_task(struct rpc_clnt *clnt, int flags,
602                                         const struct rpc_call_ops *tk_ops,
603                                         void *data)
604 {
605         return rpc_do_run_task(clnt, NULL, flags, tk_ops, data);
606 }
607 EXPORT_SYMBOL(rpc_run_task);
608
609 void
610 rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
611 {
612         task->tk_msg   = *msg;
613         task->tk_flags |= flags;
614         /* Bind the user cred */
615         if (task->tk_msg.rpc_cred != NULL)
616                 rpcauth_holdcred(task);
617         else
618                 rpcauth_bindcred(task);
619
620         if (task->tk_status == 0)
621                 task->tk_action = call_start;
622         else
623                 task->tk_action = rpc_exit_task;
624 }
625
626 /**
627  * rpc_peeraddr - extract remote peer address from clnt's xprt
628  * @clnt: RPC client structure
629  * @buf: target buffer
630  * @size: length of target buffer
631  *
632  * Returns the number of bytes that are actually in the stored address.
633  */
634 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
635 {
636         size_t bytes;
637         struct rpc_xprt *xprt = clnt->cl_xprt;
638
639         bytes = sizeof(xprt->addr);
640         if (bytes > bufsize)
641                 bytes = bufsize;
642         memcpy(buf, &clnt->cl_xprt->addr, bytes);
643         return xprt->addrlen;
644 }
645 EXPORT_SYMBOL_GPL(rpc_peeraddr);
646
647 /**
648  * rpc_peeraddr2str - return remote peer address in printable format
649  * @clnt: RPC client structure
650  * @format: address format
651  *
652  */
653 char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
654 {
655         struct rpc_xprt *xprt = clnt->cl_xprt;
656
657         if (xprt->address_strings[format] != NULL)
658                 return xprt->address_strings[format];
659         else
660                 return "unprintable";
661 }
662 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
663
664 void
665 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
666 {
667         struct rpc_xprt *xprt = clnt->cl_xprt;
668         if (xprt->ops->set_buffer_size)
669                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
670 }
671
672 /*
673  * Return size of largest payload RPC client can support, in bytes
674  *
675  * For stream transports, this is one RPC record fragment (see RFC
676  * 1831), as we don't support multi-record requests yet.  For datagram
677  * transports, this is the size of an IP packet minus the IP, UDP, and
678  * RPC header sizes.
679  */
680 size_t rpc_max_payload(struct rpc_clnt *clnt)
681 {
682         return clnt->cl_xprt->max_payload;
683 }
684 EXPORT_SYMBOL_GPL(rpc_max_payload);
685
686 /**
687  * rpc_force_rebind - force transport to check that remote port is unchanged
688  * @clnt: client to rebind
689  *
690  */
691 void rpc_force_rebind(struct rpc_clnt *clnt)
692 {
693         if (clnt->cl_autobind)
694                 xprt_clear_bound(clnt->cl_xprt);
695 }
696 EXPORT_SYMBOL_GPL(rpc_force_rebind);
697
698 /*
699  * Restart an (async) RPC call. Usually called from within the
700  * exit handler.
701  */
702 void
703 rpc_restart_call(struct rpc_task *task)
704 {
705         if (RPC_ASSASSINATED(task))
706                 return;
707
708         task->tk_action = call_start;
709 }
710
711 /*
712  * 0.  Initial state
713  *
714  *     Other FSM states can be visited zero or more times, but
715  *     this state is visited exactly once for each RPC.
716  */
717 static void
718 call_start(struct rpc_task *task)
719 {
720         struct rpc_clnt *clnt = task->tk_client;
721
722         dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
723                         clnt->cl_protname, clnt->cl_vers,
724                         task->tk_msg.rpc_proc->p_proc,
725                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
726
727         /* Increment call count */
728         task->tk_msg.rpc_proc->p_count++;
729         clnt->cl_stats->rpccnt++;
730         task->tk_action = call_reserve;
731 }
732
733 /*
734  * 1.   Reserve an RPC call slot
735  */
736 static void
737 call_reserve(struct rpc_task *task)
738 {
739         dprint_status(task);
740
741         if (!rpcauth_uptodatecred(task)) {
742                 task->tk_action = call_refresh;
743                 return;
744         }
745
746         task->tk_status  = 0;
747         task->tk_action  = call_reserveresult;
748         xprt_reserve(task);
749 }
750
751 /*
752  * 1b.  Grok the result of xprt_reserve()
753  */
754 static void
755 call_reserveresult(struct rpc_task *task)
756 {
757         int status = task->tk_status;
758
759         dprint_status(task);
760
761         /*
762          * After a call to xprt_reserve(), we must have either
763          * a request slot or else an error status.
764          */
765         task->tk_status = 0;
766         if (status >= 0) {
767                 if (task->tk_rqstp) {
768                         task->tk_action = call_allocate;
769                         return;
770                 }
771
772                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
773                                 __FUNCTION__, status);
774                 rpc_exit(task, -EIO);
775                 return;
776         }
777
778         /*
779          * Even though there was an error, we may have acquired
780          * a request slot somehow.  Make sure not to leak it.
781          */
782         if (task->tk_rqstp) {
783                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
784                                 __FUNCTION__, status);
785                 xprt_release(task);
786         }
787
788         switch (status) {
789         case -EAGAIN:   /* woken up; retry */
790                 task->tk_action = call_reserve;
791                 return;
792         case -EIO:      /* probably a shutdown */
793                 break;
794         default:
795                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
796                                 __FUNCTION__, status);
797                 break;
798         }
799         rpc_exit(task, status);
800 }
801
802 /*
803  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
804  *      (Note: buffer memory is freed in xprt_release).
805  */
806 static void
807 call_allocate(struct rpc_task *task)
808 {
809         unsigned int slack = task->tk_msg.rpc_cred->cr_auth->au_cslack;
810         struct rpc_rqst *req = task->tk_rqstp;
811         struct rpc_xprt *xprt = task->tk_xprt;
812         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
813
814         dprint_status(task);
815
816         task->tk_status = 0;
817         task->tk_action = call_bind;
818
819         if (req->rq_buffer)
820                 return;
821
822         if (proc->p_proc != 0) {
823                 BUG_ON(proc->p_arglen == 0);
824                 if (proc->p_decode != NULL)
825                         BUG_ON(proc->p_replen == 0);
826         }
827
828         /*
829          * Calculate the size (in quads) of the RPC call
830          * and reply headers, and convert both values
831          * to byte sizes.
832          */
833         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
834         req->rq_callsize <<= 2;
835         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
836         req->rq_rcvsize <<= 2;
837
838         req->rq_buffer = xprt->ops->buf_alloc(task,
839                                         req->rq_callsize + req->rq_rcvsize);
840         if (req->rq_buffer != NULL)
841                 return;
842
843         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
844
845         if (RPC_IS_ASYNC(task) || !signalled()) {
846                 xprt_release(task);
847                 task->tk_action = call_reserve;
848                 rpc_delay(task, HZ>>4);
849                 return;
850         }
851
852         rpc_exit(task, -ERESTARTSYS);
853 }
854
855 static inline int
856 rpc_task_need_encode(struct rpc_task *task)
857 {
858         return task->tk_rqstp->rq_snd_buf.len == 0;
859 }
860
861 static inline void
862 rpc_task_force_reencode(struct rpc_task *task)
863 {
864         task->tk_rqstp->rq_snd_buf.len = 0;
865 }
866
867 static inline void
868 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
869 {
870         buf->head[0].iov_base = start;
871         buf->head[0].iov_len = len;
872         buf->tail[0].iov_len = 0;
873         buf->page_len = 0;
874         buf->len = 0;
875         buf->buflen = len;
876 }
877
878 /*
879  * 3.   Encode arguments of an RPC call
880  */
881 static void
882 call_encode(struct rpc_task *task)
883 {
884         struct rpc_rqst *req = task->tk_rqstp;
885         kxdrproc_t      encode;
886         __be32          *p;
887
888         dprint_status(task);
889
890         rpc_xdr_buf_init(&req->rq_snd_buf,
891                          req->rq_buffer,
892                          req->rq_callsize);
893         rpc_xdr_buf_init(&req->rq_rcv_buf,
894                          (char *)req->rq_buffer + req->rq_callsize,
895                          req->rq_rcvsize);
896
897         /* Encode header and provided arguments */
898         encode = task->tk_msg.rpc_proc->p_encode;
899         if (!(p = call_header(task))) {
900                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
901                 rpc_exit(task, -EIO);
902                 return;
903         }
904         if (encode == NULL)
905                 return;
906
907         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
908                         task->tk_msg.rpc_argp);
909         if (task->tk_status == -ENOMEM) {
910                 /* XXX: Is this sane? */
911                 rpc_delay(task, 3*HZ);
912                 task->tk_status = -EAGAIN;
913         }
914 }
915
916 /*
917  * 4.   Get the server port number if not yet set
918  */
919 static void
920 call_bind(struct rpc_task *task)
921 {
922         struct rpc_xprt *xprt = task->tk_xprt;
923
924         dprint_status(task);
925
926         task->tk_action = call_connect;
927         if (!xprt_bound(xprt)) {
928                 task->tk_action = call_bind_status;
929                 task->tk_timeout = xprt->bind_timeout;
930                 xprt->ops->rpcbind(task);
931         }
932 }
933
934 /*
935  * 4a.  Sort out bind result
936  */
937 static void
938 call_bind_status(struct rpc_task *task)
939 {
940         int status = -EACCES;
941
942         if (task->tk_status >= 0) {
943                 dprint_status(task);
944                 task->tk_status = 0;
945                 task->tk_action = call_connect;
946                 return;
947         }
948
949         switch (task->tk_status) {
950         case -EACCES:
951                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
952                                 "unavailable\n", task->tk_pid);
953                 rpc_delay(task, 3*HZ);
954                 goto retry_timeout;
955         case -ETIMEDOUT:
956                 dprintk("RPC: %5u rpcbind request timed out\n",
957                                 task->tk_pid);
958                 goto retry_timeout;
959         case -EPFNOSUPPORT:
960                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
961                                 task->tk_pid);
962                 break;
963         case -EPROTONOSUPPORT:
964                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
965                                 task->tk_pid);
966                 task->tk_status = 0;
967                 task->tk_action = call_bind;
968                 return;
969         default:
970                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
971                                 task->tk_pid, -task->tk_status);
972                 status = -EIO;
973         }
974
975         rpc_exit(task, status);
976         return;
977
978 retry_timeout:
979         task->tk_action = call_timeout;
980 }
981
982 /*
983  * 4b.  Connect to the RPC server
984  */
985 static void
986 call_connect(struct rpc_task *task)
987 {
988         struct rpc_xprt *xprt = task->tk_xprt;
989
990         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
991                         task->tk_pid, xprt,
992                         (xprt_connected(xprt) ? "is" : "is not"));
993
994         task->tk_action = call_transmit;
995         if (!xprt_connected(xprt)) {
996                 task->tk_action = call_connect_status;
997                 if (task->tk_status < 0)
998                         return;
999                 xprt_connect(task);
1000         }
1001 }
1002
1003 /*
1004  * 4c.  Sort out connect result
1005  */
1006 static void
1007 call_connect_status(struct rpc_task *task)
1008 {
1009         struct rpc_clnt *clnt = task->tk_client;
1010         int status = task->tk_status;
1011
1012         dprint_status(task);
1013
1014         task->tk_status = 0;
1015         if (status >= 0) {
1016                 clnt->cl_stats->netreconn++;
1017                 task->tk_action = call_transmit;
1018                 return;
1019         }
1020
1021         /* Something failed: remote service port may have changed */
1022         rpc_force_rebind(clnt);
1023
1024         switch (status) {
1025         case -ENOTCONN:
1026         case -EAGAIN:
1027                 task->tk_action = call_bind;
1028                 if (!RPC_IS_SOFT(task))
1029                         return;
1030                 /* if soft mounted, test if we've timed out */
1031         case -ETIMEDOUT:
1032                 task->tk_action = call_timeout;
1033                 return;
1034         }
1035         rpc_exit(task, -EIO);
1036 }
1037
1038 /*
1039  * 5.   Transmit the RPC request, and wait for reply
1040  */
1041 static void
1042 call_transmit(struct rpc_task *task)
1043 {
1044         dprint_status(task);
1045
1046         task->tk_action = call_status;
1047         if (task->tk_status < 0)
1048                 return;
1049         task->tk_status = xprt_prepare_transmit(task);
1050         if (task->tk_status != 0)
1051                 return;
1052         task->tk_action = call_transmit_status;
1053         /* Encode here so that rpcsec_gss can use correct sequence number. */
1054         if (rpc_task_need_encode(task)) {
1055                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1056                 call_encode(task);
1057                 /* Did the encode result in an error condition? */
1058                 if (task->tk_status != 0)
1059                         return;
1060         }
1061         xprt_transmit(task);
1062         if (task->tk_status < 0)
1063                 return;
1064         /*
1065          * On success, ensure that we call xprt_end_transmit() before sleeping
1066          * in order to allow access to the socket to other RPC requests.
1067          */
1068         call_transmit_status(task);
1069         if (task->tk_msg.rpc_proc->p_decode != NULL)
1070                 return;
1071         task->tk_action = rpc_exit_task;
1072         rpc_wake_up_task(task);
1073 }
1074
1075 /*
1076  * 5a.  Handle cleanup after a transmission
1077  */
1078 static void
1079 call_transmit_status(struct rpc_task *task)
1080 {
1081         task->tk_action = call_status;
1082         /*
1083          * Special case: if we've been waiting on the socket's write_space()
1084          * callback, then don't call xprt_end_transmit().
1085          */
1086         if (task->tk_status == -EAGAIN)
1087                 return;
1088         xprt_end_transmit(task);
1089         rpc_task_force_reencode(task);
1090 }
1091
1092 /*
1093  * 6.   Sort out the RPC call status
1094  */
1095 static void
1096 call_status(struct rpc_task *task)
1097 {
1098         struct rpc_clnt *clnt = task->tk_client;
1099         struct rpc_rqst *req = task->tk_rqstp;
1100         int             status;
1101
1102         if (req->rq_received > 0 && !req->rq_bytes_sent)
1103                 task->tk_status = req->rq_received;
1104
1105         dprint_status(task);
1106
1107         status = task->tk_status;
1108         if (status >= 0) {
1109                 task->tk_action = call_decode;
1110                 return;
1111         }
1112
1113         task->tk_status = 0;
1114         switch(status) {
1115         case -EHOSTDOWN:
1116         case -EHOSTUNREACH:
1117         case -ENETUNREACH:
1118                 /*
1119                  * Delay any retries for 3 seconds, then handle as if it
1120                  * were a timeout.
1121                  */
1122                 rpc_delay(task, 3*HZ);
1123         case -ETIMEDOUT:
1124                 task->tk_action = call_timeout;
1125                 if (task->tk_client->cl_discrtry)
1126                         xprt_disconnect(task->tk_xprt);
1127                 break;
1128         case -ECONNREFUSED:
1129         case -ENOTCONN:
1130                 rpc_force_rebind(clnt);
1131                 task->tk_action = call_bind;
1132                 break;
1133         case -EAGAIN:
1134                 task->tk_action = call_transmit;
1135                 break;
1136         case -EIO:
1137                 /* shutdown or soft timeout */
1138                 rpc_exit(task, status);
1139                 break;
1140         default:
1141                 printk("%s: RPC call returned error %d\n",
1142                                clnt->cl_protname, -status);
1143                 rpc_exit(task, status);
1144         }
1145 }
1146
1147 /*
1148  * 6a.  Handle RPC timeout
1149  *      We do not release the request slot, so we keep using the
1150  *      same XID for all retransmits.
1151  */
1152 static void
1153 call_timeout(struct rpc_task *task)
1154 {
1155         struct rpc_clnt *clnt = task->tk_client;
1156
1157         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1158                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1159                 goto retry;
1160         }
1161
1162         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1163         task->tk_timeouts++;
1164
1165         if (RPC_IS_SOFT(task)) {
1166                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1167                                 clnt->cl_protname, clnt->cl_server);
1168                 rpc_exit(task, -EIO);
1169                 return;
1170         }
1171
1172         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1173                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1174                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1175                         clnt->cl_protname, clnt->cl_server);
1176         }
1177         rpc_force_rebind(clnt);
1178
1179 retry:
1180         clnt->cl_stats->rpcretrans++;
1181         task->tk_action = call_bind;
1182         task->tk_status = 0;
1183 }
1184
1185 /*
1186  * 7.   Decode the RPC reply
1187  */
1188 static void
1189 call_decode(struct rpc_task *task)
1190 {
1191         struct rpc_clnt *clnt = task->tk_client;
1192         struct rpc_rqst *req = task->tk_rqstp;
1193         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1194         __be32          *p;
1195
1196         dprintk("RPC: %5u call_decode (status %d)\n",
1197                         task->tk_pid, task->tk_status);
1198
1199         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1200                 printk(KERN_NOTICE "%s: server %s OK\n",
1201                         clnt->cl_protname, clnt->cl_server);
1202                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1203         }
1204
1205         if (task->tk_status < 12) {
1206                 if (!RPC_IS_SOFT(task)) {
1207                         task->tk_action = call_bind;
1208                         clnt->cl_stats->rpcretrans++;
1209                         goto out_retry;
1210                 }
1211                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1212                                 clnt->cl_protname, task->tk_status);
1213                 task->tk_action = call_timeout;
1214                 goto out_retry;
1215         }
1216
1217         /*
1218          * Ensure that we see all writes made by xprt_complete_rqst()
1219          * before it changed req->rq_received.
1220          */
1221         smp_rmb();
1222         req->rq_rcv_buf.len = req->rq_private_buf.len;
1223
1224         /* Check that the softirq receive buffer is valid */
1225         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1226                                 sizeof(req->rq_rcv_buf)) != 0);
1227
1228         /* Verify the RPC header */
1229         p = call_verify(task);
1230         if (IS_ERR(p)) {
1231                 if (p == ERR_PTR(-EAGAIN))
1232                         goto out_retry;
1233                 return;
1234         }
1235
1236         task->tk_action = rpc_exit_task;
1237
1238         if (decode) {
1239                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1240                                                       task->tk_msg.rpc_resp);
1241         }
1242         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1243                         task->tk_status);
1244         return;
1245 out_retry:
1246         req->rq_received = req->rq_private_buf.len = 0;
1247         task->tk_status = 0;
1248         if (task->tk_client->cl_discrtry)
1249                 xprt_disconnect(task->tk_xprt);
1250 }
1251
1252 /*
1253  * 8.   Refresh the credentials if rejected by the server
1254  */
1255 static void
1256 call_refresh(struct rpc_task *task)
1257 {
1258         dprint_status(task);
1259
1260         xprt_release(task);     /* Must do to obtain new XID */
1261         task->tk_action = call_refreshresult;
1262         task->tk_status = 0;
1263         task->tk_client->cl_stats->rpcauthrefresh++;
1264         rpcauth_refreshcred(task);
1265 }
1266
1267 /*
1268  * 8a.  Process the results of a credential refresh
1269  */
1270 static void
1271 call_refreshresult(struct rpc_task *task)
1272 {
1273         int status = task->tk_status;
1274
1275         dprint_status(task);
1276
1277         task->tk_status = 0;
1278         task->tk_action = call_reserve;
1279         if (status >= 0 && rpcauth_uptodatecred(task))
1280                 return;
1281         if (status == -EACCES) {
1282                 rpc_exit(task, -EACCES);
1283                 return;
1284         }
1285         task->tk_action = call_refresh;
1286         if (status != -ETIMEDOUT)
1287                 rpc_delay(task, 3*HZ);
1288         return;
1289 }
1290
1291 /*
1292  * Call header serialization
1293  */
1294 static __be32 *
1295 call_header(struct rpc_task *task)
1296 {
1297         struct rpc_clnt *clnt = task->tk_client;
1298         struct rpc_rqst *req = task->tk_rqstp;
1299         __be32          *p = req->rq_svec[0].iov_base;
1300
1301         /* FIXME: check buffer size? */
1302
1303         p = xprt_skip_transport_header(task->tk_xprt, p);
1304         *p++ = req->rq_xid;             /* XID */
1305         *p++ = htonl(RPC_CALL);         /* CALL */
1306         *p++ = htonl(RPC_VERSION);      /* RPC version */
1307         *p++ = htonl(clnt->cl_prog);    /* program number */
1308         *p++ = htonl(clnt->cl_vers);    /* program version */
1309         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1310         p = rpcauth_marshcred(task, p);
1311         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1312         return p;
1313 }
1314
1315 /*
1316  * Reply header verification
1317  */
1318 static __be32 *
1319 call_verify(struct rpc_task *task)
1320 {
1321         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1322         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1323         __be32  *p = iov->iov_base;
1324         u32 n;
1325         int error = -EACCES;
1326
1327         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1328                 /* RFC-1014 says that the representation of XDR data must be a
1329                  * multiple of four bytes
1330                  * - if it isn't pointer subtraction in the NFS client may give
1331                  *   undefined results
1332                  */
1333                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
1334                        " 4 bytes: 0x%x\n", task->tk_pid, __FUNCTION__,
1335                        task->tk_rqstp->rq_rcv_buf.len);
1336                 goto out_eio;
1337         }
1338         if ((len -= 3) < 0)
1339                 goto out_overflow;
1340         p += 1; /* skip XID */
1341
1342         if ((n = ntohl(*p++)) != RPC_REPLY) {
1343                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1344                                 task->tk_pid, __FUNCTION__, n);
1345                 goto out_garbage;
1346         }
1347         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1348                 if (--len < 0)
1349                         goto out_overflow;
1350                 switch ((n = ntohl(*p++))) {
1351                         case RPC_AUTH_ERROR:
1352                                 break;
1353                         case RPC_MISMATCH:
1354                                 dprintk("RPC: %5u %s: RPC call version "
1355                                                 "mismatch!\n",
1356                                                 task->tk_pid, __FUNCTION__);
1357                                 error = -EPROTONOSUPPORT;
1358                                 goto out_err;
1359                         default:
1360                                 dprintk("RPC: %5u %s: RPC call rejected, "
1361                                                 "unknown error: %x\n",
1362                                                 task->tk_pid, __FUNCTION__, n);
1363                                 goto out_eio;
1364                 }
1365                 if (--len < 0)
1366                         goto out_overflow;
1367                 switch ((n = ntohl(*p++))) {
1368                 case RPC_AUTH_REJECTEDCRED:
1369                 case RPC_AUTH_REJECTEDVERF:
1370                 case RPCSEC_GSS_CREDPROBLEM:
1371                 case RPCSEC_GSS_CTXPROBLEM:
1372                         if (!task->tk_cred_retry)
1373                                 break;
1374                         task->tk_cred_retry--;
1375                         dprintk("RPC: %5u %s: retry stale creds\n",
1376                                         task->tk_pid, __FUNCTION__);
1377                         rpcauth_invalcred(task);
1378                         task->tk_action = call_refresh;
1379                         goto out_retry;
1380                 case RPC_AUTH_BADCRED:
1381                 case RPC_AUTH_BADVERF:
1382                         /* possibly garbled cred/verf? */
1383                         if (!task->tk_garb_retry)
1384                                 break;
1385                         task->tk_garb_retry--;
1386                         dprintk("RPC: %5u %s: retry garbled creds\n",
1387                                         task->tk_pid, __FUNCTION__);
1388                         task->tk_action = call_bind;
1389                         goto out_retry;
1390                 case RPC_AUTH_TOOWEAK:
1391                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1392                                "authentication.\n", task->tk_client->cl_server);
1393                         break;
1394                 default:
1395                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
1396                                         task->tk_pid, __FUNCTION__, n);
1397                         error = -EIO;
1398                 }
1399                 dprintk("RPC: %5u %s: call rejected %d\n",
1400                                 task->tk_pid, __FUNCTION__, n);
1401                 goto out_err;
1402         }
1403         if (!(p = rpcauth_checkverf(task, p))) {
1404                 dprintk("RPC: %5u %s: auth check failed\n",
1405                                 task->tk_pid, __FUNCTION__);
1406                 goto out_garbage;               /* bad verifier, retry */
1407         }
1408         len = p - (__be32 *)iov->iov_base - 1;
1409         if (len < 0)
1410                 goto out_overflow;
1411         switch ((n = ntohl(*p++))) {
1412         case RPC_SUCCESS:
1413                 return p;
1414         case RPC_PROG_UNAVAIL:
1415                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1416                                 task->tk_pid, __FUNCTION__,
1417                                 (unsigned int)task->tk_client->cl_prog,
1418                                 task->tk_client->cl_server);
1419                 error = -EPFNOSUPPORT;
1420                 goto out_err;
1421         case RPC_PROG_MISMATCH:
1422                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1423                                 "server %s\n", task->tk_pid, __FUNCTION__,
1424                                 (unsigned int)task->tk_client->cl_prog,
1425                                 (unsigned int)task->tk_client->cl_vers,
1426                                 task->tk_client->cl_server);
1427                 error = -EPROTONOSUPPORT;
1428                 goto out_err;
1429         case RPC_PROC_UNAVAIL:
1430                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1431                                 "version %u on server %s\n",
1432                                 task->tk_pid, __FUNCTION__,
1433                                 task->tk_msg.rpc_proc,
1434                                 task->tk_client->cl_prog,
1435                                 task->tk_client->cl_vers,
1436                                 task->tk_client->cl_server);
1437                 error = -EOPNOTSUPP;
1438                 goto out_err;
1439         case RPC_GARBAGE_ARGS:
1440                 dprintk("RPC: %5u %s: server saw garbage\n",
1441                                 task->tk_pid, __FUNCTION__);
1442                 break;                  /* retry */
1443         default:
1444                 dprintk("RPC: %5u %s: server accept status: %x\n",
1445                                 task->tk_pid, __FUNCTION__, n);
1446                 /* Also retry */
1447         }
1448
1449 out_garbage:
1450         task->tk_client->cl_stats->rpcgarbage++;
1451         if (task->tk_garb_retry) {
1452                 task->tk_garb_retry--;
1453                 dprintk("RPC: %5u %s: retrying\n",
1454                                 task->tk_pid, __FUNCTION__);
1455                 task->tk_action = call_bind;
1456 out_retry:
1457                 return ERR_PTR(-EAGAIN);
1458         }
1459 out_eio:
1460         error = -EIO;
1461 out_err:
1462         rpc_exit(task, error);
1463         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1464                         __FUNCTION__, error);
1465         return ERR_PTR(error);
1466 out_overflow:
1467         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1468                         __FUNCTION__);
1469         goto out_garbage;
1470 }
1471
1472 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1473 {
1474         return 0;
1475 }
1476
1477 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1478 {
1479         return 0;
1480 }
1481
1482 static struct rpc_procinfo rpcproc_null = {
1483         .p_encode = rpcproc_encode_null,
1484         .p_decode = rpcproc_decode_null,
1485 };
1486
1487 static int rpc_ping(struct rpc_clnt *clnt, int flags)
1488 {
1489         struct rpc_message msg = {
1490                 .rpc_proc = &rpcproc_null,
1491         };
1492         int err;
1493         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1494         err = rpc_call_sync(clnt, &msg, flags);
1495         put_rpccred(msg.rpc_cred);
1496         return err;
1497 }
1498
1499 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1500 {
1501         struct rpc_message msg = {
1502                 .rpc_proc = &rpcproc_null,
1503                 .rpc_cred = cred,
1504         };
1505         return rpc_do_run_task(clnt, &msg, flags, &rpc_default_ops, NULL);
1506 }
1507 EXPORT_SYMBOL(rpc_call_null);
1508
1509 #ifdef RPC_DEBUG
1510 void rpc_show_tasks(void)
1511 {
1512         struct rpc_clnt *clnt;
1513         struct rpc_task *t;
1514
1515         spin_lock(&rpc_client_lock);
1516         if (list_empty(&all_clients))
1517                 goto out;
1518         printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
1519                 "-rpcwait -action- ---ops--\n");
1520         list_for_each_entry(clnt, &all_clients, cl_clients) {
1521                 if (list_empty(&clnt->cl_tasks))
1522                         continue;
1523                 spin_lock(&clnt->cl_lock);
1524                 list_for_each_entry(t, &clnt->cl_tasks, tk_task) {
1525                         const char *rpc_waitq = "none";
1526
1527                         if (RPC_IS_QUEUED(t))
1528                                 rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);
1529
1530                         printk("%5u %04d %04x %6d %8p %6d %8p %8ld %8s %8p %8p\n",
1531                                 t->tk_pid,
1532                                 (t->tk_msg.rpc_proc ? t->tk_msg.rpc_proc->p_proc : -1),
1533                                 t->tk_flags, t->tk_status,
1534                                 t->tk_client,
1535                                 (t->tk_client ? t->tk_client->cl_prog : 0),
1536                                 t->tk_rqstp, t->tk_timeout,
1537                                 rpc_waitq,
1538                                 t->tk_action, t->tk_ops);
1539                 }
1540                 spin_unlock(&clnt->cl_lock);
1541         }
1542 out:
1543         spin_unlock(&rpc_client_lock);
1544 }
1545 #endif