xref: /linux/net/sunrpc/clnt.c (revision ed3174d93c342b8b2eeba6bbd124707d55304a7b)
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
1555