0998e6d0966469df4ceb8f5adde3a842956093d5
[linux-2.6.git] / net / sunrpc / clnt.c
1 /*
2  *  linux/net/sunrpc/clnt.c
3  *
4  *  This file contains the high-level RPC interface.
5  *  It is modeled as a finite state machine to support both synchronous
6  *  and asynchronous requests.
7  *
8  *  -   RPC header generation and argument serialization.
9  *  -   Credential refresh.
10  *  -   TCP connect handling.
11  *  -   Retry of operation when it is suspected the operation failed because
12  *      of uid squashing on the server, or when the credentials were stale
13  *      and need to be refreshed, or when a packet was damaged in transit.
14  *      This may be have to be moved to the VFS layer.
15  *
16  *  NB: BSD uses a more intelligent approach to guessing when a request
17  *  or reply has been lost by keeping the RTO estimate for each procedure.
18  *  We currently make do with a constant timeout value.
19  *
20  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
21  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
22  */
23
24 #include <asm/system.h>
25
26 #include <linux/module.h>
27 #include <linux/types.h>
28 #include <linux/mm.h>
29 #include <linux/slab.h>
30 #include <linux/smp_lock.h>
31 #include <linux/utsname.h>
32 #include <linux/workqueue.h>
33 #include <linux/in6.h>
34
35 #include <linux/sunrpc/clnt.h>
36 #include <linux/sunrpc/rpc_pipe_fs.h>
37 #include <linux/sunrpc/metrics.h>
38
39
40 #ifdef RPC_DEBUG
41 # define RPCDBG_FACILITY        RPCDBG_CALL
42 #endif
43
44 #define dprint_status(t)                                        \
45         dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,         \
46                         __FUNCTION__, t->tk_status)
47
48 /*
49  * All RPC clients are linked into this list
50  */
51 static LIST_HEAD(all_clients);
52 static DEFINE_SPINLOCK(rpc_client_lock);
53
54 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
55
56
57 static void     call_start(struct rpc_task *task);
58 static void     call_reserve(struct rpc_task *task);
59 static void     call_reserveresult(struct rpc_task *task);
60 static void     call_allocate(struct rpc_task *task);
61 static void     call_encode(struct rpc_task *task);
62 static void     call_decode(struct rpc_task *task);
63 static void     call_bind(struct rpc_task *task);
64 static void     call_bind_status(struct rpc_task *task);
65 static void     call_transmit(struct rpc_task *task);
66 static void     call_status(struct rpc_task *task);
67 static void     call_transmit_status(struct rpc_task *task);
68 static void     call_refresh(struct rpc_task *task);
69 static void     call_refreshresult(struct rpc_task *task);
70 static void     call_timeout(struct rpc_task *task);
71 static void     call_connect(struct rpc_task *task);
72 static void     call_connect_status(struct rpc_task *task);
73 static __be32 * call_header(struct rpc_task *task);
74 static __be32 * call_verify(struct rpc_task *task);
75
76 static int      rpc_ping(struct rpc_clnt *clnt, int flags);
77
78 static void rpc_register_client(struct rpc_clnt *clnt)
79 {
80         spin_lock(&rpc_client_lock);
81         list_add(&clnt->cl_clients, &all_clients);
82         spin_unlock(&rpc_client_lock);
83 }
84
85 static void rpc_unregister_client(struct rpc_clnt *clnt)
86 {
87         spin_lock(&rpc_client_lock);
88         list_del(&clnt->cl_clients);
89         spin_unlock(&rpc_client_lock);
90 }
91
92 static int
93 rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
94 {
95         static uint32_t clntid;
96         int error;
97
98         clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
99         clnt->cl_dentry = ERR_PTR(-ENOENT);
100         if (dir_name == NULL)
101                 return 0;
102
103         clnt->cl_vfsmnt = rpc_get_mount();
104         if (IS_ERR(clnt->cl_vfsmnt))
105                 return PTR_ERR(clnt->cl_vfsmnt);
106
107         for (;;) {
108                 snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
109                                 "%s/clnt%x", dir_name,
110                                 (unsigned int)clntid++);
111                 clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
112                 clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
113                 if (!IS_ERR(clnt->cl_dentry))
114                         return 0;
115                 error = PTR_ERR(clnt->cl_dentry);
116                 if (error != -EEXIST) {
117                         printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
118                                         clnt->cl_pathname, error);
119                         rpc_put_mount();
120                         return error;
121                 }
122         }
123 }
124
125 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
126 {
127         struct rpc_program      *program = args->program;
128         struct rpc_version      *version;
129         struct rpc_clnt         *clnt = NULL;
130         struct rpc_auth         *auth;
131         int err;
132         size_t len;
133
134         /* sanity check the name before trying to print it */
135         err = -EINVAL;
136         len = strlen(args->servername);
137         if (len > RPC_MAXNETNAMELEN)
138                 goto out_no_rpciod;
139         len++;
140
141         dprintk("RPC:       creating %s client for %s (xprt %p)\n",
142                         program->name, args->servername, xprt);
143
144         err = rpciod_up();
145         if (err)
146                 goto out_no_rpciod;
147         err = -EINVAL;
148         if (!xprt)
149                 goto out_no_xprt;
150
151         if (args->version >= program->nrvers)
152                 goto out_err;
153         version = program->version[args->version];
154         if (version == NULL)
155                 goto out_err;
156
157         err = -ENOMEM;
158         clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
159         if (!clnt)
160                 goto out_err;
161         clnt->cl_parent = clnt;
162
163         clnt->cl_server = clnt->cl_inline_name;
164         if (len > sizeof(clnt->cl_inline_name)) {
165                 char *buf = kmalloc(len, GFP_KERNEL);
166                 if (buf != NULL)
167                         clnt->cl_server = buf;
168                 else
169                         len = sizeof(clnt->cl_inline_name);
170         }
171         strlcpy(clnt->cl_server, args->servername, len);
172
173         clnt->cl_xprt     = xprt;
174         clnt->cl_procinfo = version->procs;
175         clnt->cl_maxproc  = version->nrprocs;
176         clnt->cl_protname = program->name;
177         clnt->cl_prog     = program->number;
178         clnt->cl_vers     = version->number;
179         clnt->cl_stats    = program->stats;
180         clnt->cl_metrics  = rpc_alloc_iostats(clnt);
181         err = -ENOMEM;
182         if (clnt->cl_metrics == NULL)
183                 goto out_no_stats;
184         clnt->cl_program  = program;
185         INIT_LIST_HEAD(&clnt->cl_tasks);
186         spin_lock_init(&clnt->cl_lock);
187
188         if (!xprt_bound(clnt->cl_xprt))
189                 clnt->cl_autobind = 1;
190
191         clnt->cl_timeout = xprt->timeout;
192         if (args->timeout != NULL) {
193                 memcpy(&clnt->cl_timeout_default, args->timeout,
194                                 sizeof(clnt->cl_timeout_default));
195                 clnt->cl_timeout = &clnt->cl_timeout_default;
196         }
197
198         clnt->cl_rtt = &clnt->cl_rtt_default;
199         rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
200
201         kref_init(&clnt->cl_kref);
202
203         err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
204         if (err < 0)
205                 goto out_no_path;
206
207         auth = rpcauth_create(args->authflavor, clnt);
208         if (IS_ERR(auth)) {
209                 printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
210                                 args->authflavor);
211                 err = PTR_ERR(auth);
212                 goto out_no_auth;
213         }
214
215         /* save the nodename */
216         clnt->cl_nodelen = strlen(utsname()->nodename);
217         if (clnt->cl_nodelen > UNX_MAXNODENAME)
218                 clnt->cl_nodelen = UNX_MAXNODENAME;
219         memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
220         rpc_register_client(clnt);
221         return clnt;
222
223 out_no_auth:
224         if (!IS_ERR(clnt->cl_dentry)) {
225                 rpc_rmdir(clnt->cl_dentry);
226                 rpc_put_mount();
227         }
228 out_no_path:
229         rpc_free_iostats(clnt->cl_metrics);
230 out_no_stats:
231         if (clnt->cl_server != clnt->cl_inline_name)
232                 kfree(clnt->cl_server);
233         kfree(clnt);
234 out_err:
235         xprt_put(xprt);
236 out_no_xprt:
237         rpciod_down();
238 out_no_rpciod:
239         return ERR_PTR(err);
240 }
241
242 /*
243  * rpc_create - create an RPC client and transport with one call
244  * @args: rpc_clnt create argument structure
245  *
246  * Creates and initializes an RPC transport and an RPC client.
247  *
248  * It can ping the server in order to determine if it is up, and to see if
249  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
250  * this behavior so asynchronous tasks can also use rpc_create.
251  */
252 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
253 {
254         struct rpc_xprt *xprt;
255         struct rpc_clnt *clnt;
256         struct xprt_create xprtargs = {
257                 .ident = args->protocol,
258                 .srcaddr = args->saddress,
259                 .dstaddr = args->address,
260                 .addrlen = args->addrsize,
261         };
262         char servername[48];
263
264         xprt = xprt_create_transport(&xprtargs);
265         if (IS_ERR(xprt))
266                 return (struct rpc_clnt *)xprt;
267
268         /*
269          * If the caller chooses not to specify a hostname, whip
270          * up a string representation of the passed-in address.
271          */
272         if (args->servername == NULL) {
273                 servername[0] = '\0';
274                 switch (args->address->sa_family) {
275                 case AF_INET: {
276                         struct sockaddr_in *sin =
277                                         (struct sockaddr_in *)args->address;
278                         snprintf(servername, sizeof(servername), NIPQUAD_FMT,
279                                  NIPQUAD(sin->sin_addr.s_addr));
280                         break;
281                 }
282                 case AF_INET6: {
283                         struct sockaddr_in6 *sin =
284                                         (struct sockaddr_in6 *)args->address;
285                         snprintf(servername, sizeof(servername), NIP6_FMT,
286                                  NIP6(sin->sin6_addr));
287                         break;
288                 }
289                 default:
290                         /* caller wants default server name, but
291                          * address family isn't recognized. */
292                         return ERR_PTR(-EINVAL);
293                 }
294                 args->servername = servername;
295         }
296
297         xprt = xprt_create_transport(&xprtargs);
298         if (IS_ERR(xprt))
299                 return (struct rpc_clnt *)xprt;
300
301         /*
302          * By default, kernel RPC client connects from a reserved port.
303          * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
304          * but it is always enabled for rpciod, which handles the connect
305          * operation.
306          */
307         xprt->resvport = 1;
308         if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
309                 xprt->resvport = 0;
310
311         clnt = rpc_new_client(args, xprt);
312         if (IS_ERR(clnt))
313                 return clnt;
314
315         if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
316                 int err = rpc_ping(clnt, RPC_TASK_SOFT);
317                 if (err != 0) {
318                         rpc_shutdown_client(clnt);
319                         return ERR_PTR(err);
320                 }
321         }
322
323         clnt->cl_softrtry = 1;
324         if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
325                 clnt->cl_softrtry = 0;
326
327         if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
328                 clnt->cl_autobind = 1;
329         if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
330                 clnt->cl_discrtry = 1;
331
332         return clnt;
333 }
334 EXPORT_SYMBOL_GPL(rpc_create);
335
336 /*
337  * This function clones the RPC client structure. It allows us to share the
338  * same transport while varying parameters such as the authentication
339  * flavour.
340  */
341 struct rpc_clnt *
342 rpc_clone_client(struct rpc_clnt *clnt)
343 {
344         struct rpc_clnt *new;
345         int err = -ENOMEM;
346
347         new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
348         if (!new)
349                 goto out_no_clnt;
350         new->cl_parent = clnt;
351         /* Turn off autobind on clones */
352         new->cl_autobind = 0;
353         INIT_LIST_HEAD(&new->cl_tasks);
354         spin_lock_init(&new->cl_lock);
355         rpc_init_rtt(&new->cl_rtt_default, clnt->cl_timeout->to_initval);
356         new->cl_metrics = rpc_alloc_iostats(clnt);
357         if (new->cl_metrics == NULL)
358                 goto out_no_stats;
359         kref_init(&new->cl_kref);
360         err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
361         if (err != 0)
362                 goto out_no_path;
363         if (new->cl_auth)
364                 atomic_inc(&new->cl_auth->au_count);
365         xprt_get(clnt->cl_xprt);
366         kref_get(&clnt->cl_kref);
367         rpc_register_client(new);
368         rpciod_up();
369         return new;
370 out_no_path:
371         rpc_free_iostats(new->cl_metrics);
372 out_no_stats:
373         kfree(new);
374 out_no_clnt:
375         dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
376         return ERR_PTR(err);
377 }
378 EXPORT_SYMBOL_GPL(rpc_clone_client);
379
380 /*
381  * Properly shut down an RPC client, terminating all outstanding
382  * requests.
383  */
384 void rpc_shutdown_client(struct rpc_clnt *clnt)
385 {
386         dprintk("RPC:       shutting down %s client for %s\n",
387                         clnt->cl_protname, clnt->cl_server);
388
389         while (!list_empty(&clnt->cl_tasks)) {
390                 rpc_killall_tasks(clnt);
391                 wait_event_timeout(destroy_wait,
392                         list_empty(&clnt->cl_tasks), 1*HZ);
393         }
394
395         rpc_release_client(clnt);
396 }
397 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
398
399 /*
400  * Free an RPC client
401  */
402 static void
403 rpc_free_client(struct kref *kref)
404 {
405         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
406
407         dprintk("RPC:       destroying %s client for %s\n",
408                         clnt->cl_protname, clnt->cl_server);
409         if (!IS_ERR(clnt->cl_dentry)) {
410                 rpc_rmdir(clnt->cl_dentry);
411                 rpc_put_mount();
412         }
413         if (clnt->cl_parent != clnt) {
414                 rpc_release_client(clnt->cl_parent);
415                 goto out_free;
416         }
417         if (clnt->cl_server != clnt->cl_inline_name)
418                 kfree(clnt->cl_server);
419 out_free:
420         rpc_unregister_client(clnt);
421         rpc_free_iostats(clnt->cl_metrics);
422         clnt->cl_metrics = NULL;
423         xprt_put(clnt->cl_xprt);
424         rpciod_down();
425         kfree(clnt);
426 }
427
428 /*
429  * Free an RPC client
430  */
431 static void
432 rpc_free_auth(struct kref *kref)
433 {
434         struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
435
436         if (clnt->cl_auth == NULL) {
437                 rpc_free_client(kref);
438                 return;
439         }
440
441         /*
442          * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
443          *       release remaining GSS contexts. This mechanism ensures
444          *       that it can do so safely.
445          */
446         kref_init(kref);
447         rpcauth_release(clnt->cl_auth);
448         clnt->cl_auth = NULL;
449         kref_put(kref, rpc_free_client);
450 }
451
452 /*
453  * Release reference to the RPC client
454  */
455 void
456 rpc_release_client(struct rpc_clnt *clnt)
457 {
458         dprintk("RPC:       rpc_release_client(%p)\n", clnt);
459
460         if (list_empty(&clnt->cl_tasks))
461                 wake_up(&destroy_wait);
462         kref_put(&clnt->cl_kref, rpc_free_auth);
463 }
464
465 /**
466  * rpc_bind_new_program - bind a new RPC program to an existing client
467  * @old - old rpc_client
468  * @program - rpc program to set
469  * @vers - rpc program version
470  *
471  * Clones the rpc client and sets up a new RPC program. This is mainly
472  * of use for enabling different RPC programs to share the same transport.
473  * The Sun NFSv2/v3 ACL protocol can do this.
474  */
475 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
476                                       struct rpc_program *program,
477                                       u32 vers)
478 {
479         struct rpc_clnt *clnt;
480         struct rpc_version *version;
481         int err;
482
483         BUG_ON(vers >= program->nrvers || !program->version[vers]);
484         version = program->version[vers];
485         clnt = rpc_clone_client(old);
486         if (IS_ERR(clnt))
487                 goto out;
488         clnt->cl_procinfo = version->procs;
489         clnt->cl_maxproc  = version->nrprocs;
490         clnt->cl_protname = program->name;
491         clnt->cl_prog     = program->number;
492         clnt->cl_vers     = version->number;
493         clnt->cl_stats    = program->stats;
494         err = rpc_ping(clnt, RPC_TASK_SOFT);
495         if (err != 0) {
496                 rpc_shutdown_client(clnt);
497                 clnt = ERR_PTR(err);
498         }
499 out:
500         return clnt;
501 }
502 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
503
504 /*
505  * Default callback for async RPC calls
506  */
507 static void
508 rpc_default_callback(struct rpc_task *task, void *data)
509 {
510 }
511
512 static const struct rpc_call_ops rpc_default_ops = {
513         .rpc_call_done = rpc_default_callback,
514 };
515
516 /**
517  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
518  * @task_setup_data: pointer to task initialisation data
519  */
520 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
521 {
522         struct rpc_task *task, *ret;
523
524         task = rpc_new_task(task_setup_data);
525         if (task == NULL) {
526                 rpc_release_calldata(task_setup_data->callback_ops,
527                                 task_setup_data->callback_data);
528                 ret = ERR_PTR(-ENOMEM);
529                 goto out;
530         }
531
532         if (task->tk_status != 0) {
533                 ret = ERR_PTR(task->tk_status);
534                 rpc_put_task(task);
535                 goto out;
536         }
537         atomic_inc(&task->tk_count);
538         rpc_execute(task);
539         ret = task;
540 out:
541         return ret;
542 }
543 EXPORT_SYMBOL_GPL(rpc_run_task);
544
545 /**
546  * rpc_call_sync - Perform a synchronous RPC call
547  * @clnt: pointer to RPC client
548  * @msg: RPC call parameters
549  * @flags: RPC call flags
550  */
551 int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
552 {
553         struct rpc_task *task;
554         struct rpc_task_setup task_setup_data = {
555                 .rpc_client = clnt,
556                 .rpc_message = msg,
557                 .callback_ops = &rpc_default_ops,
558                 .flags = flags,
559         };
560         int status;
561
562         BUG_ON(flags & RPC_TASK_ASYNC);
563
564         task = rpc_run_task(&task_setup_data);
565         if (IS_ERR(task))
566                 return PTR_ERR(task);
567         status = task->tk_status;
568         rpc_put_task(task);
569         return status;
570 }
571 EXPORT_SYMBOL_GPL(rpc_call_sync);
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         struct rpc_task_setup task_setup_data = {
587                 .rpc_client = clnt,
588                 .rpc_message = msg,
589                 .callback_ops = tk_ops,
590                 .callback_data = data,
591                 .flags = flags|RPC_TASK_ASYNC,
592         };
593
594         task = rpc_run_task(&task_setup_data);
595         if (IS_ERR(task))
596                 return PTR_ERR(task);
597         rpc_put_task(task);
598         return 0;
599 }
600 EXPORT_SYMBOL_GPL(rpc_call_async);
601
602 void
603 rpc_call_start(struct rpc_task *task)
604 {
605         task->tk_action = call_start;
606 }
607 EXPORT_SYMBOL_GPL(rpc_call_start);
608
609 /**
610  * rpc_peeraddr - extract remote peer address from clnt's xprt
611  * @clnt: RPC client structure
612  * @buf: target buffer
613  * @size: length of target buffer
614  *
615  * Returns the number of bytes that are actually in the stored address.
616  */
617 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
618 {
619         size_t bytes;
620         struct rpc_xprt *xprt = clnt->cl_xprt;
621
622         bytes = sizeof(xprt->addr);
623         if (bytes > bufsize)
624                 bytes = bufsize;
625         memcpy(buf, &clnt->cl_xprt->addr, bytes);
626         return xprt->addrlen;
627 }
628 EXPORT_SYMBOL_GPL(rpc_peeraddr);
629
630 /**
631  * rpc_peeraddr2str - return remote peer address in printable format
632  * @clnt: RPC client structure
633  * @format: address format
634  *
635  */
636 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
637                              enum rpc_display_format_t format)
638 {
639         struct rpc_xprt *xprt = clnt->cl_xprt;
640
641         if (xprt->address_strings[format] != NULL)
642                 return xprt->address_strings[format];
643         else
644                 return "unprintable";
645 }
646 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
647
648 void
649 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
650 {
651         struct rpc_xprt *xprt = clnt->cl_xprt;
652         if (xprt->ops->set_buffer_size)
653                 xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
654 }
655 EXPORT_SYMBOL_GPL(rpc_setbufsize);
656
657 /*
658  * Return size of largest payload RPC client can support, in bytes
659  *
660  * For stream transports, this is one RPC record fragment (see RFC
661  * 1831), as we don't support multi-record requests yet.  For datagram
662  * transports, this is the size of an IP packet minus the IP, UDP, and
663  * RPC header sizes.
664  */
665 size_t rpc_max_payload(struct rpc_clnt *clnt)
666 {
667         return clnt->cl_xprt->max_payload;
668 }
669 EXPORT_SYMBOL_GPL(rpc_max_payload);
670
671 /**
672  * rpc_force_rebind - force transport to check that remote port is unchanged
673  * @clnt: client to rebind
674  *
675  */
676 void rpc_force_rebind(struct rpc_clnt *clnt)
677 {
678         if (clnt->cl_autobind)
679                 xprt_clear_bound(clnt->cl_xprt);
680 }
681 EXPORT_SYMBOL_GPL(rpc_force_rebind);
682
683 /*
684  * Restart an (async) RPC call. Usually called from within the
685  * exit handler.
686  */
687 void
688 rpc_restart_call(struct rpc_task *task)
689 {
690         if (RPC_ASSASSINATED(task))
691                 return;
692
693         task->tk_action = call_start;
694 }
695 EXPORT_SYMBOL_GPL(rpc_restart_call);
696
697 /*
698  * 0.  Initial state
699  *
700  *     Other FSM states can be visited zero or more times, but
701  *     this state is visited exactly once for each RPC.
702  */
703 static void
704 call_start(struct rpc_task *task)
705 {
706         struct rpc_clnt *clnt = task->tk_client;
707
708         dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
709                         clnt->cl_protname, clnt->cl_vers,
710                         task->tk_msg.rpc_proc->p_proc,
711                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
712
713         /* Increment call count */
714         task->tk_msg.rpc_proc->p_count++;
715         clnt->cl_stats->rpccnt++;
716         task->tk_action = call_reserve;
717 }
718
719 /*
720  * 1.   Reserve an RPC call slot
721  */
722 static void
723 call_reserve(struct rpc_task *task)
724 {
725         dprint_status(task);
726
727         if (!rpcauth_uptodatecred(task)) {
728                 task->tk_action = call_refresh;
729                 return;
730         }
731
732         task->tk_status  = 0;
733         task->tk_action  = call_reserveresult;
734         xprt_reserve(task);
735 }
736
737 /*
738  * 1b.  Grok the result of xprt_reserve()
739  */
740 static void
741 call_reserveresult(struct rpc_task *task)
742 {
743         int status = task->tk_status;
744
745         dprint_status(task);
746
747         /*
748          * After a call to xprt_reserve(), we must have either
749          * a request slot or else an error status.
750          */
751         task->tk_status = 0;
752         if (status >= 0) {
753                 if (task->tk_rqstp) {
754                         task->tk_action = call_allocate;
755                         return;
756                 }
757
758                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
759                                 __FUNCTION__, status);
760                 rpc_exit(task, -EIO);
761                 return;
762         }
763
764         /*
765          * Even though there was an error, we may have acquired
766          * a request slot somehow.  Make sure not to leak it.
767          */
768         if (task->tk_rqstp) {
769                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
770                                 __FUNCTION__, status);
771                 xprt_release(task);
772         }
773
774         switch (status) {
775         case -EAGAIN:   /* woken up; retry */
776                 task->tk_action = call_reserve;
777                 return;
778         case -EIO:      /* probably a shutdown */
779                 break;
780         default:
781                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
782                                 __FUNCTION__, status);
783                 break;
784         }
785         rpc_exit(task, status);
786 }
787
788 /*
789  * 2.   Allocate the buffer. For details, see sched.c:rpc_malloc.
790  *      (Note: buffer memory is freed in xprt_release).
791  */
792 static void
793 call_allocate(struct rpc_task *task)
794 {
795         unsigned int slack = task->tk_msg.rpc_cred->cr_auth->au_cslack;
796         struct rpc_rqst *req = task->tk_rqstp;
797         struct rpc_xprt *xprt = task->tk_xprt;
798         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
799
800         dprint_status(task);
801
802         task->tk_status = 0;
803         task->tk_action = call_bind;
804
805         if (req->rq_buffer)
806                 return;
807
808         if (proc->p_proc != 0) {
809                 BUG_ON(proc->p_arglen == 0);
810                 if (proc->p_decode != NULL)
811                         BUG_ON(proc->p_replen == 0);
812         }
813
814         /*
815          * Calculate the size (in quads) of the RPC call
816          * and reply headers, and convert both values
817          * to byte sizes.
818          */
819         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
820         req->rq_callsize <<= 2;
821         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
822         req->rq_rcvsize <<= 2;
823
824         req->rq_buffer = xprt->ops->buf_alloc(task,
825                                         req->rq_callsize + req->rq_rcvsize);
826         if (req->rq_buffer != NULL)
827                 return;
828
829         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
830
831         if (RPC_IS_ASYNC(task) || !signalled()) {
832                 task->tk_action = call_allocate;
833                 rpc_delay(task, HZ>>4);
834                 return;
835         }
836
837         rpc_exit(task, -ERESTARTSYS);
838 }
839
840 static inline int
841 rpc_task_need_encode(struct rpc_task *task)
842 {
843         return task->tk_rqstp->rq_snd_buf.len == 0;
844 }
845
846 static inline void
847 rpc_task_force_reencode(struct rpc_task *task)
848 {
849         task->tk_rqstp->rq_snd_buf.len = 0;
850 }
851
852 static inline void
853 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
854 {
855         buf->head[0].iov_base = start;
856         buf->head[0].iov_len = len;
857         buf->tail[0].iov_len = 0;
858         buf->page_len = 0;
859         buf->flags = 0;
860         buf->len = 0;
861         buf->buflen = len;
862 }
863
864 /*
865  * 3.   Encode arguments of an RPC call
866  */
867 static void
868 call_encode(struct rpc_task *task)
869 {
870         struct rpc_rqst *req = task->tk_rqstp;
871         kxdrproc_t      encode;
872         __be32          *p;
873
874         dprint_status(task);
875
876         rpc_xdr_buf_init(&req->rq_snd_buf,
877                          req->rq_buffer,
878                          req->rq_callsize);
879         rpc_xdr_buf_init(&req->rq_rcv_buf,
880                          (char *)req->rq_buffer + req->rq_callsize,
881                          req->rq_rcvsize);
882
883         /* Encode header and provided arguments */
884         encode = task->tk_msg.rpc_proc->p_encode;
885         if (!(p = call_header(task))) {
886                 printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
887                 rpc_exit(task, -EIO);
888                 return;
889         }
890         if (encode == NULL)
891                 return;
892
893         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
894                         task->tk_msg.rpc_argp);
895         if (task->tk_status == -ENOMEM) {
896                 /* XXX: Is this sane? */
897                 rpc_delay(task, 3*HZ);
898                 task->tk_status = -EAGAIN;
899         }
900 }
901
902 /*
903  * 4.   Get the server port number if not yet set
904  */
905 static void
906 call_bind(struct rpc_task *task)
907 {
908         struct rpc_xprt *xprt = task->tk_xprt;
909
910         dprint_status(task);
911
912         task->tk_action = call_connect;
913         if (!xprt_bound(xprt)) {
914                 task->tk_action = call_bind_status;
915                 task->tk_timeout = xprt->bind_timeout;
916                 xprt->ops->rpcbind(task);
917         }
918 }
919
920 /*
921  * 4a.  Sort out bind result
922  */
923 static void
924 call_bind_status(struct rpc_task *task)
925 {
926         int status = -EIO;
927
928         if (task->tk_status >= 0) {
929                 dprint_status(task);
930                 task->tk_status = 0;
931                 task->tk_action = call_connect;
932                 return;
933         }
934
935         switch (task->tk_status) {
936         case -EAGAIN:
937                 dprintk("RPC: %5u rpcbind waiting for another request "
938                                 "to finish\n", task->tk_pid);
939                 /* avoid busy-waiting here -- could be a network outage. */
940                 rpc_delay(task, 5*HZ);
941                 goto retry_timeout;
942         case -EACCES:
943                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
944                                 "unavailable\n", task->tk_pid);
945                 /* fail immediately if this is an RPC ping */
946                 if (task->tk_msg.rpc_proc->p_proc == 0) {
947                         status = -EOPNOTSUPP;
948                         break;
949                 }
950                 rpc_delay(task, 3*HZ);
951                 goto retry_timeout;
952         case -ETIMEDOUT:
953                 dprintk("RPC: %5u rpcbind request timed out\n",
954                                 task->tk_pid);
955                 goto retry_timeout;
956         case -EPFNOSUPPORT:
957                 /* server doesn't support any rpcbind version we know of */
958                 dprintk("RPC: %5u remote rpcbind service unavailable\n",
959                                 task->tk_pid);
960                 break;
961         case -EPROTONOSUPPORT:
962                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
963                                 task->tk_pid);
964                 task->tk_status = 0;
965                 task->tk_action = call_bind;
966                 return;
967         default:
968                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
969                                 task->tk_pid, -task->tk_status);
970         }
971
972         rpc_exit(task, status);
973         return;
974
975 retry_timeout:
976         task->tk_action = call_timeout;
977 }
978
979 /*
980  * 4b.  Connect to the RPC server
981  */
982 static void
983 call_connect(struct rpc_task *task)
984 {
985         struct rpc_xprt *xprt = task->tk_xprt;
986
987         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
988                         task->tk_pid, xprt,
989                         (xprt_connected(xprt) ? "is" : "is not"));
990
991         task->tk_action = call_transmit;
992         if (!xprt_connected(xprt)) {
993                 task->tk_action = call_connect_status;
994                 if (task->tk_status < 0)
995                         return;
996                 xprt_connect(task);
997         }
998 }
999
1000 /*
1001  * 4c.  Sort out connect result
1002  */
1003 static void
1004 call_connect_status(struct rpc_task *task)
1005 {
1006         struct rpc_clnt *clnt = task->tk_client;
1007         int status = task->tk_status;
1008
1009         dprint_status(task);
1010
1011         task->tk_status = 0;
1012         if (status >= 0) {
1013                 clnt->cl_stats->netreconn++;
1014                 task->tk_action = call_transmit;
1015                 return;
1016         }
1017
1018         /* Something failed: remote service port may have changed */
1019         rpc_force_rebind(clnt);
1020
1021         switch (status) {
1022         case -ENOTCONN:
1023         case -EAGAIN:
1024                 task->tk_action = call_bind;
1025                 if (!RPC_IS_SOFT(task))
1026                         return;
1027                 /* if soft mounted, test if we've timed out */
1028         case -ETIMEDOUT:
1029                 task->tk_action = call_timeout;
1030                 return;
1031         }
1032         rpc_exit(task, -EIO);
1033 }
1034
1035 /*
1036  * 5.   Transmit the RPC request, and wait for reply
1037  */
1038 static void
1039 call_transmit(struct rpc_task *task)
1040 {
1041         dprint_status(task);
1042
1043         task->tk_action = call_status;
1044         if (task->tk_status < 0)
1045                 return;
1046         task->tk_status = xprt_prepare_transmit(task);
1047         if (task->tk_status != 0)
1048                 return;
1049         task->tk_action = call_transmit_status;
1050         /* Encode here so that rpcsec_gss can use correct sequence number. */
1051         if (rpc_task_need_encode(task)) {
1052                 BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1053                 call_encode(task);
1054                 /* Did the encode result in an error condition? */
1055                 if (task->tk_status != 0)
1056                         return;
1057         }
1058         xprt_transmit(task);
1059         if (task->tk_status < 0)
1060                 return;
1061         /*
1062          * On success, ensure that we call xprt_end_transmit() before sleeping
1063          * in order to allow access to the socket to other RPC requests.
1064          */
1065         call_transmit_status(task);
1066         if (task->tk_msg.rpc_proc->p_decode != NULL)
1067                 return;
1068         task->tk_action = rpc_exit_task;
1069         rpc_wake_up_task(task);
1070 }
1071
1072 /*
1073  * 5a.  Handle cleanup after a transmission
1074  */
1075 static void
1076 call_transmit_status(struct rpc_task *task)
1077 {
1078         task->tk_action = call_status;
1079         /*
1080          * Special case: if we've been waiting on the socket's write_space()
1081          * callback, then don't call xprt_end_transmit().
1082          */
1083         if (task->tk_status == -EAGAIN)
1084                 return;
1085         xprt_end_transmit(task);
1086         rpc_task_force_reencode(task);
1087 }
1088
1089 /*
1090  * 6.   Sort out the RPC call status
1091  */
1092 static void
1093 call_status(struct rpc_task *task)
1094 {
1095         struct rpc_clnt *clnt = task->tk_client;
1096         struct rpc_rqst *req = task->tk_rqstp;
1097         int             status;
1098
1099         if (req->rq_received > 0 && !req->rq_bytes_sent)
1100                 task->tk_status = req->rq_received;
1101
1102         dprint_status(task);
1103
1104         status = task->tk_status;
1105         if (status >= 0) {
1106                 task->tk_action = call_decode;
1107                 return;
1108         }
1109
1110         task->tk_status = 0;
1111         switch(status) {
1112         case -EHOSTDOWN:
1113         case -EHOSTUNREACH:
1114         case -ENETUNREACH:
1115                 /*
1116                  * Delay any retries for 3 seconds, then handle as if it
1117                  * were a timeout.
1118                  */
1119                 rpc_delay(task, 3*HZ);
1120         case -ETIMEDOUT:
1121                 task->tk_action = call_timeout;
1122                 if (task->tk_client->cl_discrtry)
1123                         xprt_force_disconnect(task->tk_xprt);
1124                 break;
1125         case -ECONNREFUSED:
1126         case -ENOTCONN:
1127                 rpc_force_rebind(clnt);
1128                 task->tk_action = call_bind;
1129                 break;
1130         case -EAGAIN:
1131                 task->tk_action = call_transmit;
1132                 break;
1133         case -EIO:
1134                 /* shutdown or soft timeout */
1135                 rpc_exit(task, status);
1136                 break;
1137         default:
1138                 printk("%s: RPC call returned error %d\n",
1139                                clnt->cl_protname, -status);
1140                 rpc_exit(task, status);
1141         }
1142 }
1143
1144 /*
1145  * 6a.  Handle RPC timeout
1146  *      We do not release the request slot, so we keep using the
1147  *      same XID for all retransmits.
1148  */
1149 static void
1150 call_timeout(struct rpc_task *task)
1151 {
1152         struct rpc_clnt *clnt = task->tk_client;
1153
1154         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1155                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1156                 goto retry;
1157         }
1158
1159         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1160         task->tk_timeouts++;
1161
1162         if (RPC_IS_SOFT(task)) {
1163                 printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1164                                 clnt->cl_protname, clnt->cl_server);
1165                 rpc_exit(task, -EIO);
1166                 return;
1167         }
1168
1169         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1170                 task->tk_flags |= RPC_CALL_MAJORSEEN;
1171                 printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1172                         clnt->cl_protname, clnt->cl_server);
1173         }
1174         rpc_force_rebind(clnt);
1175
1176 retry:
1177         clnt->cl_stats->rpcretrans++;
1178         task->tk_action = call_bind;
1179         task->tk_status = 0;
1180 }
1181
1182 /*
1183  * 7.   Decode the RPC reply
1184  */
1185 static void
1186 call_decode(struct rpc_task *task)
1187 {
1188         struct rpc_clnt *clnt = task->tk_client;
1189         struct rpc_rqst *req = task->tk_rqstp;
1190         kxdrproc_t      decode = task->tk_msg.rpc_proc->p_decode;
1191         __be32          *p;
1192
1193         dprintk("RPC: %5u call_decode (status %d)\n",
1194                         task->tk_pid, task->tk_status);
1195
1196         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1197                 printk(KERN_NOTICE "%s: server %s OK\n",
1198                         clnt->cl_protname, clnt->cl_server);
1199                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1200         }
1201
1202         if (task->tk_status < 12) {
1203                 if (!RPC_IS_SOFT(task)) {
1204                         task->tk_action = call_bind;
1205                         clnt->cl_stats->rpcretrans++;
1206                         goto out_retry;
1207                 }
1208                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1209                                 clnt->cl_protname, task->tk_status);
1210                 task->tk_action = call_timeout;
1211                 goto out_retry;
1212         }
1213
1214         /*
1215          * Ensure that we see all writes made by xprt_complete_rqst()
1216          * before it changed req->rq_received.
1217          */
1218         smp_rmb();
1219         req->rq_rcv_buf.len = req->rq_private_buf.len;
1220
1221         /* Check that the softirq receive buffer is valid */
1222         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1223                                 sizeof(req->rq_rcv_buf)) != 0);
1224
1225         /* Verify the RPC header */
1226         p = call_verify(task);
1227         if (IS_ERR(p)) {
1228                 if (p == ERR_PTR(-EAGAIN))
1229                         goto out_retry;
1230                 return;
1231         }
1232
1233         task->tk_action = rpc_exit_task;
1234
1235         if (decode) {
1236                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1237                                                       task->tk_msg.rpc_resp);
1238         }
1239         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1240                         task->tk_status);
1241         return;
1242 out_retry:
1243         req->rq_received = req->rq_private_buf.len = 0;
1244         task->tk_status = 0;
1245         if (task->tk_client->cl_discrtry)
1246                 xprt_force_disconnect(task->tk_xprt);
1247 }
1248
1249 /*
1250  * 8.   Refresh the credentials if rejected by the server
1251  */
1252 static void
1253 call_refresh(struct rpc_task *task)
1254 {
1255         dprint_status(task);
1256
1257         task->tk_action = call_refreshresult;
1258         task->tk_status = 0;
1259         task->tk_client->cl_stats->rpcauthrefresh++;
1260         rpcauth_refreshcred(task);
1261 }
1262
1263 /*
1264  * 8a.  Process the results of a credential refresh
1265  */
1266 static void
1267 call_refreshresult(struct rpc_task *task)
1268 {
1269         int status = task->tk_status;
1270
1271         dprint_status(task);
1272
1273         task->tk_status = 0;
1274         task->tk_action = call_reserve;
1275         if (status >= 0 && rpcauth_uptodatecred(task))
1276                 return;
1277         if (status == -EACCES) {
1278                 rpc_exit(task, -EACCES);
1279                 return;
1280         }
1281         task->tk_action = call_refresh;
1282         if (status != -ETIMEDOUT)
1283                 rpc_delay(task, 3*HZ);
1284         return;
1285 }
1286
1287 /*
1288  * Call header serialization
1289  */
1290 static __be32 *
1291 call_header(struct rpc_task *task)
1292 {
1293         struct rpc_clnt *clnt = task->tk_client;
1294         struct rpc_rqst *req = task->tk_rqstp;
1295         __be32          *p = req->rq_svec[0].iov_base;
1296
1297         /* FIXME: check buffer size? */
1298
1299         p = xprt_skip_transport_header(task->tk_xprt, p);
1300         *p++ = req->rq_xid;             /* XID */
1301         *p++ = htonl(RPC_CALL);         /* CALL */
1302         *p++ = htonl(RPC_VERSION);      /* RPC version */
1303         *p++ = htonl(clnt->cl_prog);    /* program number */
1304         *p++ = htonl(clnt->cl_vers);    /* program version */
1305         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
1306         p = rpcauth_marshcred(task, p);
1307         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1308         return p;
1309 }
1310
1311 /*
1312  * Reply header verification
1313  */
1314 static __be32 *
1315 call_verify(struct rpc_task *task)
1316 {
1317         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1318         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1319         __be32  *p = iov->iov_base;
1320         u32 n;
1321         int error = -EACCES;
1322
1323         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1324                 /* RFC-1014 says that the representation of XDR data must be a
1325                  * multiple of four bytes
1326                  * - if it isn't pointer subtraction in the NFS client may give
1327                  *   undefined results
1328                  */
1329                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
1330                        " 4 bytes: 0x%x\n", task->tk_pid, __FUNCTION__,
1331                        task->tk_rqstp->rq_rcv_buf.len);
1332                 goto out_eio;
1333         }
1334         if ((len -= 3) < 0)
1335                 goto out_overflow;
1336         p += 1; /* skip XID */
1337
1338         if ((n = ntohl(*p++)) != RPC_REPLY) {
1339                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1340                                 task->tk_pid, __FUNCTION__, n);
1341                 goto out_garbage;
1342         }
1343         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1344                 if (--len < 0)
1345                         goto out_overflow;
1346                 switch ((n = ntohl(*p++))) {
1347                         case RPC_AUTH_ERROR:
1348                                 break;
1349                         case RPC_MISMATCH:
1350                                 dprintk("RPC: %5u %s: RPC call version "
1351                                                 "mismatch!\n",
1352                                                 task->tk_pid, __FUNCTION__);
1353                                 error = -EPROTONOSUPPORT;
1354                                 goto out_err;
1355                         default:
1356                                 dprintk("RPC: %5u %s: RPC call rejected, "
1357                                                 "unknown error: %x\n",
1358                                                 task->tk_pid, __FUNCTION__, n);
1359                                 goto out_eio;
1360                 }
1361                 if (--len < 0)
1362                         goto out_overflow;
1363                 switch ((n = ntohl(*p++))) {
1364                 case RPC_AUTH_REJECTEDCRED:
1365                 case RPC_AUTH_REJECTEDVERF:
1366                 case RPCSEC_GSS_CREDPROBLEM:
1367                 case RPCSEC_GSS_CTXPROBLEM:
1368                         if (!task->tk_cred_retry)
1369                                 break;
1370                         task->tk_cred_retry--;
1371                         dprintk("RPC: %5u %s: retry stale creds\n",
1372                                         task->tk_pid, __FUNCTION__);
1373                         rpcauth_invalcred(task);
1374                         /* Ensure we obtain a new XID! */
1375                         xprt_release(task);
1376                         task->tk_action = call_refresh;
1377                         goto out_retry;
1378                 case RPC_AUTH_BADCRED:
1379                 case RPC_AUTH_BADVERF:
1380                         /* possibly garbled cred/verf? */
1381                         if (!task->tk_garb_retry)
1382                                 break;
1383                         task->tk_garb_retry--;
1384                         dprintk("RPC: %5u %s: retry garbled creds\n",
1385                                         task->tk_pid, __FUNCTION__);
1386                         task->tk_action = call_bind;
1387                         goto out_retry;
1388                 case RPC_AUTH_TOOWEAK:
1389                         printk(KERN_NOTICE "call_verify: server %s requires stronger "
1390                                "authentication.\n", task->tk_client->cl_server);
1391                         break;
1392                 default:
1393                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
1394                                         task->tk_pid, __FUNCTION__, n);
1395                         error = -EIO;
1396                 }
1397                 dprintk("RPC: %5u %s: call rejected %d\n",
1398                                 task->tk_pid, __FUNCTION__, n);
1399                 goto out_err;
1400         }
1401         if (!(p = rpcauth_checkverf(task, p))) {
1402                 dprintk("RPC: %5u %s: auth check failed\n",
1403                                 task->tk_pid, __FUNCTION__);
1404                 goto out_garbage;               /* bad verifier, retry */
1405         }
1406         len = p - (__be32 *)iov->iov_base - 1;
1407         if (len < 0)
1408                 goto out_overflow;
1409         switch ((n = ntohl(*p++))) {
1410         case RPC_SUCCESS:
1411                 return p;
1412         case RPC_PROG_UNAVAIL:
1413                 dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1414                                 task->tk_pid, __FUNCTION__,
1415                                 (unsigned int)task->tk_client->cl_prog,
1416                                 task->tk_client->cl_server);
1417                 error = -EPFNOSUPPORT;
1418                 goto out_err;
1419         case RPC_PROG_MISMATCH:
1420                 dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1421                                 "server %s\n", task->tk_pid, __FUNCTION__,
1422                                 (unsigned int)task->tk_client->cl_prog,
1423                                 (unsigned int)task->tk_client->cl_vers,
1424                                 task->tk_client->cl_server);
1425                 error = -EPROTONOSUPPORT;
1426                 goto out_err;
1427         case RPC_PROC_UNAVAIL:
1428                 dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1429                                 "version %u on server %s\n",
1430                                 task->tk_pid, __FUNCTION__,
1431                                 task->tk_msg.rpc_proc,
1432                                 task->tk_client->cl_prog,
1433                                 task->tk_client->cl_vers,
1434                                 task->tk_client->cl_server);
1435                 error = -EOPNOTSUPP;
1436                 goto out_err;
1437         case RPC_GARBAGE_ARGS:
1438                 dprintk("RPC: %5u %s: server saw garbage\n",
1439                                 task->tk_pid, __FUNCTION__);
1440                 break;                  /* retry */
1441         default:
1442                 dprintk("RPC: %5u %s: server accept status: %x\n",
1443                                 task->tk_pid, __FUNCTION__, n);
1444                 /* Also retry */
1445         }
1446
1447 out_garbage:
1448         task->tk_client->cl_stats->rpcgarbage++;
1449         if (task->tk_garb_retry) {
1450                 task->tk_garb_retry--;
1451                 dprintk("RPC: %5u %s: retrying\n",
1452                                 task->tk_pid, __FUNCTION__);
1453                 task->tk_action = call_bind;
1454 out_retry:
1455                 return ERR_PTR(-EAGAIN);
1456         }
1457 out_eio:
1458         error = -EIO;
1459 out_err:
1460         rpc_exit(task, error);
1461         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1462                         __FUNCTION__, error);
1463         return ERR_PTR(error);
1464 out_overflow:
1465         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1466                         __FUNCTION__);
1467         goto out_garbage;
1468 }
1469
1470 static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1471 {
1472         return 0;
1473 }
1474
1475 static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1476 {
1477         return 0;
1478 }
1479
1480 static struct rpc_procinfo rpcproc_null = {
1481         .p_encode = rpcproc_encode_null,
1482         .p_decode = rpcproc_decode_null,
1483 };
1484
1485 static int rpc_ping(struct rpc_clnt *clnt, int flags)
1486 {
1487         struct rpc_message msg = {
1488                 .rpc_proc = &rpcproc_null,
1489         };
1490         int err;
1491         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1492         err = rpc_call_sync(clnt, &msg, flags);
1493         put_rpccred(msg.rpc_cred);
1494         return err;
1495 }
1496
1497 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1498 {
1499         struct rpc_message msg = {
1500                 .rpc_proc = &rpcproc_null,
1501                 .rpc_cred = cred,
1502         };
1503         struct rpc_task_setup task_setup_data = {
1504                 .rpc_client = clnt,
1505                 .rpc_message = &msg,
1506                 .callback_ops = &rpc_default_ops,
1507                 .flags = flags,
1508         };
1509         return rpc_run_task(&task_setup_data);
1510 }
1511 EXPORT_SYMBOL_GPL(rpc_call_null);
1512
1513 #ifdef RPC_DEBUG
1514 void rpc_show_tasks(void)
1515 {
1516         struct rpc_clnt *clnt;
1517         struct rpc_task *t;
1518
1519         spin_lock(&rpc_client_lock);
1520         if (list_empty(&all_clients))
1521                 goto out;
1522         printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
1523                 "-rpcwait -action- ---ops--\n");
1524         list_for_each_entry(clnt, &all_clients, cl_clients) {
1525                 if (list_empty(&clnt->cl_tasks))
1526                         continue;
1527                 spin_lock(&clnt->cl_lock);
1528                 list_for_each_entry(t, &clnt->cl_tasks, tk_task) {
1529                         const char *rpc_waitq = "none";
1530                         int proc;
1531
1532                         if (t->tk_msg.rpc_proc)
1533                                 proc = t->tk_msg.rpc_proc->p_proc;
1534                         else
1535                                 proc = -1;
1536
1537                         if (RPC_IS_QUEUED(t))
1538                                 rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);
1539
1540                         printk("%5u %04d %04x %6d %8p %6d %8p %8ld %8s %8p %8p\n",
1541                                 t->tk_pid, proc,
1542                                 t->tk_flags, t->tk_status,
1543                                 t->tk_client,
1544                                 (t->tk_client ? t->tk_client->cl_prog : 0),
1545                                 t->tk_rqstp, t->tk_timeout,
1546                                 rpc_waitq,
1547                                 t->tk_action, t->tk_ops);
1548                 }
1549                 spin_unlock(&clnt->cl_lock);
1550         }
1551 out:
1552         spin_unlock(&rpc_client_lock);
1553 }
1554 #endif