clnt.c revision 84115e1cd4a3614c4e566d4cce31381dce3dbef9
1/*
2 *  linux/net/sunrpc/clnt.c
3 *
4 *  This file contains the high-level RPC interface.
5 *  It is modeled as a finite state machine to support both synchronous
6 *  and asynchronous requests.
7 *
8 *  -	RPC header generation and argument serialization.
9 *  -	Credential refresh.
10 *  -	TCP connect handling.
11 *  -	Retry of operation when it is suspected the operation failed because
12 *	of uid squashing on the server, or when the credentials were stale
13 *	and need to be refreshed, or when a packet was damaged in transit.
14 *	This may be have to be moved to the VFS layer.
15 *
16 *  NB: BSD uses a more intelligent approach to guessing when a request
17 *  or reply has been lost by keeping the RTO estimate for each procedure.
18 *  We currently make do with a constant timeout value.
19 *
20 *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
21 *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
22 */
23
24#include <asm/system.h>
25
26#include <linux/module.h>
27#include <linux/types.h>
28#include <linux/mm.h>
29#include <linux/slab.h>
30#include <linux/smp_lock.h>
31#include <linux/utsname.h>
32#include <linux/workqueue.h>
33
34#include <linux/sunrpc/clnt.h>
35#include <linux/sunrpc/rpc_pipe_fs.h>
36#include <linux/sunrpc/metrics.h>
37
38
39#ifdef RPC_DEBUG
40# define RPCDBG_FACILITY	RPCDBG_CALL
41#endif
42
43#define dprint_status(t)					\
44	dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,		\
45			__FUNCTION__, t->tk_status)
46
47/*
48 * All RPC clients are linked into this list
49 */
50static LIST_HEAD(all_clients);
51static DEFINE_SPINLOCK(rpc_client_lock);
52
53static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
54
55
56static void	call_start(struct rpc_task *task);
57static void	call_reserve(struct rpc_task *task);
58static void	call_reserveresult(struct rpc_task *task);
59static void	call_allocate(struct rpc_task *task);
60static void	call_encode(struct rpc_task *task);
61static void	call_decode(struct rpc_task *task);
62static void	call_bind(struct rpc_task *task);
63static void	call_bind_status(struct rpc_task *task);
64static void	call_transmit(struct rpc_task *task);
65static void	call_status(struct rpc_task *task);
66static void	call_transmit_status(struct rpc_task *task);
67static void	call_refresh(struct rpc_task *task);
68static void	call_refreshresult(struct rpc_task *task);
69static void	call_timeout(struct rpc_task *task);
70static void	call_connect(struct rpc_task *task);
71static void	call_connect_status(struct rpc_task *task);
72static __be32 *	call_header(struct rpc_task *task);
73static __be32 *	call_verify(struct rpc_task *task);
74
75static int	rpc_ping(struct rpc_clnt *clnt, int flags);
76
77static void rpc_register_client(struct rpc_clnt *clnt)
78{
79	spin_lock(&rpc_client_lock);
80	list_add(&clnt->cl_clients, &all_clients);
81	spin_unlock(&rpc_client_lock);
82}
83
84static void rpc_unregister_client(struct rpc_clnt *clnt)
85{
86	spin_lock(&rpc_client_lock);
87	list_del(&clnt->cl_clients);
88	spin_unlock(&rpc_client_lock);
89}
90
91static int
92rpc_setup_pipedir(struct rpc_clnt *clnt, char *dir_name)
93{
94	static uint32_t clntid;
95	int error;
96
97	clnt->cl_vfsmnt = ERR_PTR(-ENOENT);
98	clnt->cl_dentry = ERR_PTR(-ENOENT);
99	if (dir_name == NULL)
100		return 0;
101
102	clnt->cl_vfsmnt = rpc_get_mount();
103	if (IS_ERR(clnt->cl_vfsmnt))
104		return PTR_ERR(clnt->cl_vfsmnt);
105
106	for (;;) {
107		snprintf(clnt->cl_pathname, sizeof(clnt->cl_pathname),
108				"%s/clnt%x", dir_name,
109				(unsigned int)clntid++);
110		clnt->cl_pathname[sizeof(clnt->cl_pathname) - 1] = '\0';
111		clnt->cl_dentry = rpc_mkdir(clnt->cl_pathname, clnt);
112		if (!IS_ERR(clnt->cl_dentry))
113			return 0;
114		error = PTR_ERR(clnt->cl_dentry);
115		if (error != -EEXIST) {
116			printk(KERN_INFO "RPC: Couldn't create pipefs entry %s, error %d\n",
117					clnt->cl_pathname, error);
118			rpc_put_mount();
119			return error;
120		}
121	}
122}
123
124static struct rpc_clnt * rpc_new_client(struct rpc_xprt *xprt, char *servname, struct rpc_program *program, u32 vers, rpc_authflavor_t flavor)
125{
126	struct rpc_version	*version;
127	struct rpc_clnt		*clnt = NULL;
128	struct rpc_auth		*auth;
129	int err;
130	size_t len;
131
132	/* sanity check the name before trying to print it */
133	err = -EINVAL;
134	len = strlen(servname);
135	if (len > RPC_MAXNETNAMELEN)
136		goto out_no_rpciod;
137	len++;
138
139	dprintk("RPC:       creating %s client for %s (xprt %p)\n",
140			program->name, servname, xprt);
141
142	err = rpciod_up();
143	if (err)
144		goto out_no_rpciod;
145	err = -EINVAL;
146	if (!xprt)
147		goto out_no_xprt;
148	if (vers >= program->nrvers || !(version = program->version[vers]))
149		goto out_err;
150
151	err = -ENOMEM;
152	clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
153	if (!clnt)
154		goto out_err;
155	clnt->cl_parent = clnt;
156
157	clnt->cl_server = clnt->cl_inline_name;
158	if (len > sizeof(clnt->cl_inline_name)) {
159		char *buf = kmalloc(len, GFP_KERNEL);
160		if (buf != 0)
161			clnt->cl_server = buf;
162		else
163			len = sizeof(clnt->cl_inline_name);
164	}
165	strlcpy(clnt->cl_server, servname, len);
166
167	clnt->cl_xprt     = xprt;
168	clnt->cl_procinfo = version->procs;
169	clnt->cl_maxproc  = version->nrprocs;
170	clnt->cl_protname = program->name;
171	clnt->cl_prog     = program->number;
172	clnt->cl_vers     = version->number;
173	clnt->cl_stats    = program->stats;
174	clnt->cl_metrics  = rpc_alloc_iostats(clnt);
175	err = -ENOMEM;
176	if (clnt->cl_metrics == NULL)
177		goto out_no_stats;
178	clnt->cl_program  = program;
179	INIT_LIST_HEAD(&clnt->cl_tasks);
180	spin_lock_init(&clnt->cl_lock);
181
182	if (!xprt_bound(clnt->cl_xprt))
183		clnt->cl_autobind = 1;
184
185	clnt->cl_rtt = &clnt->cl_rtt_default;
186	rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
187
188	kref_init(&clnt->cl_kref);
189
190	err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
191	if (err < 0)
192		goto out_no_path;
193
194	auth = rpcauth_create(flavor, clnt);
195	if (IS_ERR(auth)) {
196		printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
197				flavor);
198		err = PTR_ERR(auth);
199		goto out_no_auth;
200	}
201
202	/* save the nodename */
203	clnt->cl_nodelen = strlen(utsname()->nodename);
204	if (clnt->cl_nodelen > UNX_MAXNODENAME)
205		clnt->cl_nodelen = UNX_MAXNODENAME;
206	memcpy(clnt->cl_nodename, utsname()->nodename, clnt->cl_nodelen);
207	rpc_register_client(clnt);
208	return clnt;
209
210out_no_auth:
211	if (!IS_ERR(clnt->cl_dentry)) {
212		rpc_rmdir(clnt->cl_dentry);
213		rpc_put_mount();
214	}
215out_no_path:
216	rpc_free_iostats(clnt->cl_metrics);
217out_no_stats:
218	if (clnt->cl_server != clnt->cl_inline_name)
219		kfree(clnt->cl_server);
220	kfree(clnt);
221out_err:
222	xprt_put(xprt);
223out_no_xprt:
224	rpciod_down();
225out_no_rpciod:
226	return ERR_PTR(err);
227}
228
229/*
230 * rpc_create - create an RPC client and transport with one call
231 * @args: rpc_clnt create argument structure
232 *
233 * Creates and initializes an RPC transport and an RPC client.
234 *
235 * It can ping the server in order to determine if it is up, and to see if
236 * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
237 * this behavior so asynchronous tasks can also use rpc_create.
238 */
239struct rpc_clnt *rpc_create(struct rpc_create_args *args)
240{
241	struct rpc_xprt *xprt;
242	struct rpc_clnt *clnt;
243	struct xprt_create xprtargs = {
244		.ident = args->protocol,
245		.srcaddr = args->saddress,
246		.dstaddr = args->address,
247		.addrlen = args->addrsize,
248		.timeout = args->timeout
249	};
250	char servername[20];
251
252	xprt = xprt_create_transport(&xprtargs);
253	if (IS_ERR(xprt))
254		return (struct rpc_clnt *)xprt;
255
256	/*
257	 * If the caller chooses not to specify a hostname, whip
258	 * up a string representation of the passed-in address.
259	 */
260	if (args->servername == NULL) {
261		struct sockaddr_in *addr =
262					(struct sockaddr_in *) args->address;
263		snprintf(servername, sizeof(servername), NIPQUAD_FMT,
264			NIPQUAD(addr->sin_addr.s_addr));
265		args->servername = servername;
266	}
267
268	/*
269	 * By default, kernel RPC client connects from a reserved port.
270	 * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
271	 * but it is always enabled for rpciod, which handles the connect
272	 * operation.
273	 */
274	xprt->resvport = 1;
275	if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
276		xprt->resvport = 0;
277
278	clnt = rpc_new_client(xprt, args->servername, args->program,
279				args->version, args->authflavor);
280	if (IS_ERR(clnt))
281		return clnt;
282
283	if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
284		int err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
285		if (err != 0) {
286			rpc_shutdown_client(clnt);
287			return ERR_PTR(err);
288		}
289	}
290
291	clnt->cl_softrtry = 1;
292	if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
293		clnt->cl_softrtry = 0;
294
295	if (args->flags & RPC_CLNT_CREATE_INTR)
296		clnt->cl_intr = 1;
297	if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
298		clnt->cl_autobind = 1;
299	if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
300		clnt->cl_discrtry = 1;
301
302	return clnt;
303}
304EXPORT_SYMBOL_GPL(rpc_create);
305
306/*
307 * This function clones the RPC client structure. It allows us to share the
308 * same transport while varying parameters such as the authentication
309 * flavour.
310 */
311struct rpc_clnt *
312rpc_clone_client(struct rpc_clnt *clnt)
313{
314	struct rpc_clnt *new;
315	int err = -ENOMEM;
316
317	new = kmemdup(clnt, sizeof(*new), GFP_KERNEL);
318	if (!new)
319		goto out_no_clnt;
320	new->cl_parent = clnt;
321	/* Turn off autobind on clones */
322	new->cl_autobind = 0;
323	INIT_LIST_HEAD(&new->cl_tasks);
324	spin_lock_init(&new->cl_lock);
325	rpc_init_rtt(&new->cl_rtt_default, clnt->cl_xprt->timeout.to_initval);
326	new->cl_metrics = rpc_alloc_iostats(clnt);
327	if (new->cl_metrics == NULL)
328		goto out_no_stats;
329	kref_init(&new->cl_kref);
330	err = rpc_setup_pipedir(new, clnt->cl_program->pipe_dir_name);
331	if (err != 0)
332		goto out_no_path;
333	if (new->cl_auth)
334		atomic_inc(&new->cl_auth->au_count);
335	xprt_get(clnt->cl_xprt);
336	kref_get(&clnt->cl_kref);
337	rpc_register_client(new);
338	rpciod_up();
339	return new;
340out_no_path:
341	rpc_free_iostats(new->cl_metrics);
342out_no_stats:
343	kfree(new);
344out_no_clnt:
345	dprintk("RPC:       %s: returned error %d\n", __FUNCTION__, err);
346	return ERR_PTR(err);
347}
348EXPORT_SYMBOL_GPL(rpc_clone_client);
349
350/*
351 * Properly shut down an RPC client, terminating all outstanding
352 * requests.
353 */
354void rpc_shutdown_client(struct rpc_clnt *clnt)
355{
356	dprintk("RPC:       shutting down %s client for %s\n",
357			clnt->cl_protname, clnt->cl_server);
358
359	while (!list_empty(&clnt->cl_tasks)) {
360		rpc_killall_tasks(clnt);
361		wait_event_timeout(destroy_wait,
362			list_empty(&clnt->cl_tasks), 1*HZ);
363	}
364
365	rpc_release_client(clnt);
366}
367EXPORT_SYMBOL_GPL(rpc_shutdown_client);
368
369/*
370 * Free an RPC client
371 */
372static void
373rpc_free_client(struct kref *kref)
374{
375	struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
376
377	dprintk("RPC:       destroying %s client for %s\n",
378			clnt->cl_protname, clnt->cl_server);
379	if (!IS_ERR(clnt->cl_dentry)) {
380		rpc_rmdir(clnt->cl_dentry);
381		rpc_put_mount();
382	}
383	if (clnt->cl_parent != clnt) {
384		rpc_release_client(clnt->cl_parent);
385		goto out_free;
386	}
387	if (clnt->cl_server != clnt->cl_inline_name)
388		kfree(clnt->cl_server);
389out_free:
390	rpc_unregister_client(clnt);
391	rpc_free_iostats(clnt->cl_metrics);
392	clnt->cl_metrics = NULL;
393	xprt_put(clnt->cl_xprt);
394	rpciod_down();
395	kfree(clnt);
396}
397
398/*
399 * Free an RPC client
400 */
401static void
402rpc_free_auth(struct kref *kref)
403{
404	struct rpc_clnt *clnt = container_of(kref, struct rpc_clnt, cl_kref);
405
406	if (clnt->cl_auth == NULL) {
407		rpc_free_client(kref);
408		return;
409	}
410
411	/*
412	 * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
413	 *       release remaining GSS contexts. This mechanism ensures
414	 *       that it can do so safely.
415	 */
416	kref_init(kref);
417	rpcauth_release(clnt->cl_auth);
418	clnt->cl_auth = NULL;
419	kref_put(kref, rpc_free_client);
420}
421
422/*
423 * Release reference to the RPC client
424 */
425void
426rpc_release_client(struct rpc_clnt *clnt)
427{
428	dprintk("RPC:       rpc_release_client(%p)\n", clnt);
429
430	if (list_empty(&clnt->cl_tasks))
431		wake_up(&destroy_wait);
432	kref_put(&clnt->cl_kref, rpc_free_auth);
433}
434
435/**
436 * rpc_bind_new_program - bind a new RPC program to an existing client
437 * @old - old rpc_client
438 * @program - rpc program to set
439 * @vers - rpc program version
440 *
441 * Clones the rpc client and sets up a new RPC program. This is mainly
442 * of use for enabling different RPC programs to share the same transport.
443 * The Sun NFSv2/v3 ACL protocol can do this.
444 */
445struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
446				      struct rpc_program *program,
447				      u32 vers)
448{
449	struct rpc_clnt *clnt;
450	struct rpc_version *version;
451	int err;
452
453	BUG_ON(vers >= program->nrvers || !program->version[vers]);
454	version = program->version[vers];
455	clnt = rpc_clone_client(old);
456	if (IS_ERR(clnt))
457		goto out;
458	clnt->cl_procinfo = version->procs;
459	clnt->cl_maxproc  = version->nrprocs;
460	clnt->cl_protname = program->name;
461	clnt->cl_prog     = program->number;
462	clnt->cl_vers     = version->number;
463	clnt->cl_stats    = program->stats;
464	err = rpc_ping(clnt, RPC_TASK_SOFT|RPC_TASK_NOINTR);
465	if (err != 0) {
466		rpc_shutdown_client(clnt);
467		clnt = ERR_PTR(err);
468	}
469out:
470	return clnt;
471}
472EXPORT_SYMBOL_GPL(rpc_bind_new_program);
473
474/*
475 * Default callback for async RPC calls
476 */
477static void
478rpc_default_callback(struct rpc_task *task, void *data)
479{
480}
481
482static const struct rpc_call_ops rpc_default_ops = {
483	.rpc_call_done = rpc_default_callback,
484};
485
486/*
487 *	Export the signal mask handling for synchronous code that
488 *	sleeps on RPC calls
489 */
490#define RPC_INTR_SIGNALS (sigmask(SIGHUP) | sigmask(SIGINT) | sigmask(SIGQUIT) | sigmask(SIGTERM))
491
492static void rpc_save_sigmask(sigset_t *oldset, int intr)
493{
494	unsigned long	sigallow = sigmask(SIGKILL);
495	sigset_t sigmask;
496
497	/* Block all signals except those listed in sigallow */
498	if (intr)
499		sigallow |= RPC_INTR_SIGNALS;
500	siginitsetinv(&sigmask, sigallow);
501	sigprocmask(SIG_BLOCK, &sigmask, oldset);
502}
503
504static inline void rpc_task_sigmask(struct rpc_task *task, sigset_t *oldset)
505{
506	rpc_save_sigmask(oldset, !RPC_TASK_UNINTERRUPTIBLE(task));
507}
508
509static inline void rpc_restore_sigmask(sigset_t *oldset)
510{
511	sigprocmask(SIG_SETMASK, oldset, NULL);
512}
513
514void rpc_clnt_sigmask(struct rpc_clnt *clnt, sigset_t *oldset)
515{
516	rpc_save_sigmask(oldset, clnt->cl_intr);
517}
518EXPORT_SYMBOL_GPL(rpc_clnt_sigmask);
519
520void rpc_clnt_sigunmask(struct rpc_clnt *clnt, sigset_t *oldset)
521{
522	rpc_restore_sigmask(oldset);
523}
524EXPORT_SYMBOL_GPL(rpc_clnt_sigunmask);
525
526static
527struct rpc_task *rpc_do_run_task(const struct rpc_task_setup *task_setup_data)
528{
529	struct rpc_task *task, *ret;
530	sigset_t oldset;
531
532	task = rpc_new_task(task_setup_data);
533	if (task == NULL) {
534		rpc_release_calldata(task_setup_data->callback_ops,
535				task_setup_data->callback_data);
536		return ERR_PTR(-ENOMEM);
537	}
538
539	/* Mask signals on synchronous RPC calls and RPCSEC_GSS upcalls */
540	rpc_task_sigmask(task, &oldset);
541	if (task_setup_data->rpc_message != NULL) {
542		rpc_call_setup(task, task_setup_data->rpc_message, 0);
543		if (task->tk_status != 0) {
544			ret = ERR_PTR(task->tk_status);
545			rpc_put_task(task);
546			goto out;
547		}
548	}
549	atomic_inc(&task->tk_count);
550	rpc_execute(task);
551	ret = task;
552out:
553	rpc_restore_sigmask(&oldset);
554	return ret;
555}
556
557/**
558 * rpc_call_sync - Perform a synchronous RPC call
559 * @clnt: pointer to RPC client
560 * @msg: RPC call parameters
561 * @flags: RPC call flags
562 */
563int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
564{
565	struct rpc_task	*task;
566	struct rpc_task_setup task_setup_data = {
567		.rpc_client = clnt,
568		.rpc_message = msg,
569		.callback_ops = &rpc_default_ops,
570		.flags = flags,
571	};
572	int status;
573
574	BUG_ON(flags & RPC_TASK_ASYNC);
575
576	task = rpc_do_run_task(&task_setup_data);
577	if (IS_ERR(task))
578		return PTR_ERR(task);
579	status = task->tk_status;
580	rpc_put_task(task);
581	return status;
582}
583EXPORT_SYMBOL_GPL(rpc_call_sync);
584
585/**
586 * rpc_call_async - Perform an asynchronous RPC call
587 * @clnt: pointer to RPC client
588 * @msg: RPC call parameters
589 * @flags: RPC call flags
590 * @ops: RPC call ops
591 * @data: user call data
592 */
593int
594rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
595	       const struct rpc_call_ops *tk_ops, void *data)
596{
597	struct rpc_task	*task;
598	struct rpc_task_setup task_setup_data = {
599		.rpc_client = clnt,
600		.rpc_message = msg,
601		.callback_ops = tk_ops,
602		.callback_data = data,
603		.flags = flags|RPC_TASK_ASYNC,
604	};
605
606	task = rpc_do_run_task(&task_setup_data);
607	if (IS_ERR(task))
608		return PTR_ERR(task);
609	rpc_put_task(task);
610	return 0;
611}
612EXPORT_SYMBOL_GPL(rpc_call_async);
613
614/**
615 * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
616 * @clnt: pointer to RPC client
617 * @flags: RPC flags
618 * @ops: RPC call ops
619 * @data: user call data
620 */
621struct rpc_task *rpc_run_task(struct rpc_clnt *clnt, int flags,
622					const struct rpc_call_ops *tk_ops,
623					void *data)
624{
625	struct rpc_task_setup task_setup_data = {
626		.rpc_client = clnt,
627		.callback_ops = tk_ops,
628		.callback_data = data,
629		.flags = flags,
630	};
631
632	return rpc_do_run_task(&task_setup_data);
633}
634EXPORT_SYMBOL_GPL(rpc_run_task);
635
636void
637rpc_call_setup(struct rpc_task *task, const struct rpc_message *msg, int flags)
638{
639	task->tk_msg   = *msg;
640	task->tk_flags |= flags;
641	/* Bind the user cred */
642	if (task->tk_msg.rpc_cred != NULL)
643		rpcauth_holdcred(task);
644	else
645		rpcauth_bindcred(task);
646
647	if (task->tk_status == 0)
648		task->tk_action = call_start;
649	else
650		task->tk_action = rpc_exit_task;
651}
652EXPORT_SYMBOL_GPL(rpc_call_setup);
653
654/**
655 * rpc_peeraddr - extract remote peer address from clnt's xprt
656 * @clnt: RPC client structure
657 * @buf: target buffer
658 * @size: length of target buffer
659 *
660 * Returns the number of bytes that are actually in the stored address.
661 */
662size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
663{
664	size_t bytes;
665	struct rpc_xprt *xprt = clnt->cl_xprt;
666
667	bytes = sizeof(xprt->addr);
668	if (bytes > bufsize)
669		bytes = bufsize;
670	memcpy(buf, &clnt->cl_xprt->addr, bytes);
671	return xprt->addrlen;
672}
673EXPORT_SYMBOL_GPL(rpc_peeraddr);
674
675/**
676 * rpc_peeraddr2str - return remote peer address in printable format
677 * @clnt: RPC client structure
678 * @format: address format
679 *
680 */
681char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
682{
683	struct rpc_xprt *xprt = clnt->cl_xprt;
684
685	if (xprt->address_strings[format] != NULL)
686		return xprt->address_strings[format];
687	else
688		return "unprintable";
689}
690EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
691
692void
693rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
694{
695	struct rpc_xprt *xprt = clnt->cl_xprt;
696	if (xprt->ops->set_buffer_size)
697		xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
698}
699EXPORT_SYMBOL_GPL(rpc_setbufsize);
700
701/*
702 * Return size of largest payload RPC client can support, in bytes
703 *
704 * For stream transports, this is one RPC record fragment (see RFC
705 * 1831), as we don't support multi-record requests yet.  For datagram
706 * transports, this is the size of an IP packet minus the IP, UDP, and
707 * RPC header sizes.
708 */
709size_t rpc_max_payload(struct rpc_clnt *clnt)
710{
711	return clnt->cl_xprt->max_payload;
712}
713EXPORT_SYMBOL_GPL(rpc_max_payload);
714
715/**
716 * rpc_force_rebind - force transport to check that remote port is unchanged
717 * @clnt: client to rebind
718 *
719 */
720void rpc_force_rebind(struct rpc_clnt *clnt)
721{
722	if (clnt->cl_autobind)
723		xprt_clear_bound(clnt->cl_xprt);
724}
725EXPORT_SYMBOL_GPL(rpc_force_rebind);
726
727/*
728 * Restart an (async) RPC call. Usually called from within the
729 * exit handler.
730 */
731void
732rpc_restart_call(struct rpc_task *task)
733{
734	if (RPC_ASSASSINATED(task))
735		return;
736
737	task->tk_action = call_start;
738}
739EXPORT_SYMBOL_GPL(rpc_restart_call);
740
741/*
742 * 0.  Initial state
743 *
744 *     Other FSM states can be visited zero or more times, but
745 *     this state is visited exactly once for each RPC.
746 */
747static void
748call_start(struct rpc_task *task)
749{
750	struct rpc_clnt	*clnt = task->tk_client;
751
752	dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
753			clnt->cl_protname, clnt->cl_vers,
754			task->tk_msg.rpc_proc->p_proc,
755			(RPC_IS_ASYNC(task) ? "async" : "sync"));
756
757	/* Increment call count */
758	task->tk_msg.rpc_proc->p_count++;
759	clnt->cl_stats->rpccnt++;
760	task->tk_action = call_reserve;
761}
762
763/*
764 * 1.	Reserve an RPC call slot
765 */
766static void
767call_reserve(struct rpc_task *task)
768{
769	dprint_status(task);
770
771	if (!rpcauth_uptodatecred(task)) {
772		task->tk_action = call_refresh;
773		return;
774	}
775
776	task->tk_status  = 0;
777	task->tk_action  = call_reserveresult;
778	xprt_reserve(task);
779}
780
781/*
782 * 1b.	Grok the result of xprt_reserve()
783 */
784static void
785call_reserveresult(struct rpc_task *task)
786{
787	int status = task->tk_status;
788
789	dprint_status(task);
790
791	/*
792	 * After a call to xprt_reserve(), we must have either
793	 * a request slot or else an error status.
794	 */
795	task->tk_status = 0;
796	if (status >= 0) {
797		if (task->tk_rqstp) {
798			task->tk_action = call_allocate;
799			return;
800		}
801
802		printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
803				__FUNCTION__, status);
804		rpc_exit(task, -EIO);
805		return;
806	}
807
808	/*
809	 * Even though there was an error, we may have acquired
810	 * a request slot somehow.  Make sure not to leak it.
811	 */
812	if (task->tk_rqstp) {
813		printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
814				__FUNCTION__, status);
815		xprt_release(task);
816	}
817
818	switch (status) {
819	case -EAGAIN:	/* woken up; retry */
820		task->tk_action = call_reserve;
821		return;
822	case -EIO:	/* probably a shutdown */
823		break;
824	default:
825		printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
826				__FUNCTION__, status);
827		break;
828	}
829	rpc_exit(task, status);
830}
831
832/*
833 * 2.	Allocate the buffer. For details, see sched.c:rpc_malloc.
834 *	(Note: buffer memory is freed in xprt_release).
835 */
836static void
837call_allocate(struct rpc_task *task)
838{
839	unsigned int slack = task->tk_msg.rpc_cred->cr_auth->au_cslack;
840	struct rpc_rqst *req = task->tk_rqstp;
841	struct rpc_xprt *xprt = task->tk_xprt;
842	struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
843
844	dprint_status(task);
845
846	task->tk_status = 0;
847	task->tk_action = call_bind;
848
849	if (req->rq_buffer)
850		return;
851
852	if (proc->p_proc != 0) {
853		BUG_ON(proc->p_arglen == 0);
854		if (proc->p_decode != NULL)
855			BUG_ON(proc->p_replen == 0);
856	}
857
858	/*
859	 * Calculate the size (in quads) of the RPC call
860	 * and reply headers, and convert both values
861	 * to byte sizes.
862	 */
863	req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
864	req->rq_callsize <<= 2;
865	req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
866	req->rq_rcvsize <<= 2;
867
868	req->rq_buffer = xprt->ops->buf_alloc(task,
869					req->rq_callsize + req->rq_rcvsize);
870	if (req->rq_buffer != NULL)
871		return;
872
873	dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
874
875	if (RPC_IS_ASYNC(task) || !signalled()) {
876		task->tk_action = call_allocate;
877		rpc_delay(task, HZ>>4);
878		return;
879	}
880
881	rpc_exit(task, -ERESTARTSYS);
882}
883
884static inline int
885rpc_task_need_encode(struct rpc_task *task)
886{
887	return task->tk_rqstp->rq_snd_buf.len == 0;
888}
889
890static inline void
891rpc_task_force_reencode(struct rpc_task *task)
892{
893	task->tk_rqstp->rq_snd_buf.len = 0;
894}
895
896static inline void
897rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
898{
899	buf->head[0].iov_base = start;
900	buf->head[0].iov_len = len;
901	buf->tail[0].iov_len = 0;
902	buf->page_len = 0;
903	buf->flags = 0;
904	buf->len = 0;
905	buf->buflen = len;
906}
907
908/*
909 * 3.	Encode arguments of an RPC call
910 */
911static void
912call_encode(struct rpc_task *task)
913{
914	struct rpc_rqst	*req = task->tk_rqstp;
915	kxdrproc_t	encode;
916	__be32		*p;
917
918	dprint_status(task);
919
920	rpc_xdr_buf_init(&req->rq_snd_buf,
921			 req->rq_buffer,
922			 req->rq_callsize);
923	rpc_xdr_buf_init(&req->rq_rcv_buf,
924			 (char *)req->rq_buffer + req->rq_callsize,
925			 req->rq_rcvsize);
926
927	/* Encode header and provided arguments */
928	encode = task->tk_msg.rpc_proc->p_encode;
929	if (!(p = call_header(task))) {
930		printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
931		rpc_exit(task, -EIO);
932		return;
933	}
934	if (encode == NULL)
935		return;
936
937	task->tk_status = rpcauth_wrap_req(task, encode, req, p,
938			task->tk_msg.rpc_argp);
939	if (task->tk_status == -ENOMEM) {
940		/* XXX: Is this sane? */
941		rpc_delay(task, 3*HZ);
942		task->tk_status = -EAGAIN;
943	}
944}
945
946/*
947 * 4.	Get the server port number if not yet set
948 */
949static void
950call_bind(struct rpc_task *task)
951{
952	struct rpc_xprt *xprt = task->tk_xprt;
953
954	dprint_status(task);
955
956	task->tk_action = call_connect;
957	if (!xprt_bound(xprt)) {
958		task->tk_action = call_bind_status;
959		task->tk_timeout = xprt->bind_timeout;
960		xprt->ops->rpcbind(task);
961	}
962}
963
964/*
965 * 4a.	Sort out bind result
966 */
967static void
968call_bind_status(struct rpc_task *task)
969{
970	int status = -EIO;
971
972	if (task->tk_status >= 0) {
973		dprint_status(task);
974		task->tk_status = 0;
975		task->tk_action = call_connect;
976		return;
977	}
978
979	switch (task->tk_status) {
980	case -EAGAIN:
981		dprintk("RPC: %5u rpcbind waiting for another request "
982				"to finish\n", task->tk_pid);
983		/* avoid busy-waiting here -- could be a network outage. */
984		rpc_delay(task, 5*HZ);
985		goto retry_timeout;
986	case -EACCES:
987		dprintk("RPC: %5u remote rpcbind: RPC program/version "
988				"unavailable\n", task->tk_pid);
989		/* fail immediately if this is an RPC ping */
990		if (task->tk_msg.rpc_proc->p_proc == 0) {
991			status = -EOPNOTSUPP;
992			break;
993		}
994		rpc_delay(task, 3*HZ);
995		goto retry_timeout;
996	case -ETIMEDOUT:
997		dprintk("RPC: %5u rpcbind request timed out\n",
998				task->tk_pid);
999		goto retry_timeout;
1000	case -EPFNOSUPPORT:
1001		/* server doesn't support any rpcbind version we know of */
1002		dprintk("RPC: %5u remote rpcbind service unavailable\n",
1003				task->tk_pid);
1004		break;
1005	case -EPROTONOSUPPORT:
1006		dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1007				task->tk_pid);
1008		task->tk_status = 0;
1009		task->tk_action = call_bind;
1010		return;
1011	default:
1012		dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1013				task->tk_pid, -task->tk_status);
1014	}
1015
1016	rpc_exit(task, status);
1017	return;
1018
1019retry_timeout:
1020	task->tk_action = call_timeout;
1021}
1022
1023/*
1024 * 4b.	Connect to the RPC server
1025 */
1026static void
1027call_connect(struct rpc_task *task)
1028{
1029	struct rpc_xprt *xprt = task->tk_xprt;
1030
1031	dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1032			task->tk_pid, xprt,
1033			(xprt_connected(xprt) ? "is" : "is not"));
1034
1035	task->tk_action = call_transmit;
1036	if (!xprt_connected(xprt)) {
1037		task->tk_action = call_connect_status;
1038		if (task->tk_status < 0)
1039			return;
1040		xprt_connect(task);
1041	}
1042}
1043
1044/*
1045 * 4c.	Sort out connect result
1046 */
1047static void
1048call_connect_status(struct rpc_task *task)
1049{
1050	struct rpc_clnt *clnt = task->tk_client;
1051	int status = task->tk_status;
1052
1053	dprint_status(task);
1054
1055	task->tk_status = 0;
1056	if (status >= 0) {
1057		clnt->cl_stats->netreconn++;
1058		task->tk_action = call_transmit;
1059		return;
1060	}
1061
1062	/* Something failed: remote service port may have changed */
1063	rpc_force_rebind(clnt);
1064
1065	switch (status) {
1066	case -ENOTCONN:
1067	case -EAGAIN:
1068		task->tk_action = call_bind;
1069		if (!RPC_IS_SOFT(task))
1070			return;
1071		/* if soft mounted, test if we've timed out */
1072	case -ETIMEDOUT:
1073		task->tk_action = call_timeout;
1074		return;
1075	}
1076	rpc_exit(task, -EIO);
1077}
1078
1079/*
1080 * 5.	Transmit the RPC request, and wait for reply
1081 */
1082static void
1083call_transmit(struct rpc_task *task)
1084{
1085	dprint_status(task);
1086
1087	task->tk_action = call_status;
1088	if (task->tk_status < 0)
1089		return;
1090	task->tk_status = xprt_prepare_transmit(task);
1091	if (task->tk_status != 0)
1092		return;
1093	task->tk_action = call_transmit_status;
1094	/* Encode here so that rpcsec_gss can use correct sequence number. */
1095	if (rpc_task_need_encode(task)) {
1096		BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1097		call_encode(task);
1098		/* Did the encode result in an error condition? */
1099		if (task->tk_status != 0)
1100			return;
1101	}
1102	xprt_transmit(task);
1103	if (task->tk_status < 0)
1104		return;
1105	/*
1106	 * On success, ensure that we call xprt_end_transmit() before sleeping
1107	 * in order to allow access to the socket to other RPC requests.
1108	 */
1109	call_transmit_status(task);
1110	if (task->tk_msg.rpc_proc->p_decode != NULL)
1111		return;
1112	task->tk_action = rpc_exit_task;
1113	rpc_wake_up_task(task);
1114}
1115
1116/*
1117 * 5a.	Handle cleanup after a transmission
1118 */
1119static void
1120call_transmit_status(struct rpc_task *task)
1121{
1122	task->tk_action = call_status;
1123	/*
1124	 * Special case: if we've been waiting on the socket's write_space()
1125	 * callback, then don't call xprt_end_transmit().
1126	 */
1127	if (task->tk_status == -EAGAIN)
1128		return;
1129	xprt_end_transmit(task);
1130	rpc_task_force_reencode(task);
1131}
1132
1133/*
1134 * 6.	Sort out the RPC call status
1135 */
1136static void
1137call_status(struct rpc_task *task)
1138{
1139	struct rpc_clnt	*clnt = task->tk_client;
1140	struct rpc_rqst	*req = task->tk_rqstp;
1141	int		status;
1142
1143	if (req->rq_received > 0 && !req->rq_bytes_sent)
1144		task->tk_status = req->rq_received;
1145
1146	dprint_status(task);
1147
1148	status = task->tk_status;
1149	if (status >= 0) {
1150		task->tk_action = call_decode;
1151		return;
1152	}
1153
1154	task->tk_status = 0;
1155	switch(status) {
1156	case -EHOSTDOWN:
1157	case -EHOSTUNREACH:
1158	case -ENETUNREACH:
1159		/*
1160		 * Delay any retries for 3 seconds, then handle as if it
1161		 * were a timeout.
1162		 */
1163		rpc_delay(task, 3*HZ);
1164	case -ETIMEDOUT:
1165		task->tk_action = call_timeout;
1166		if (task->tk_client->cl_discrtry)
1167			xprt_force_disconnect(task->tk_xprt);
1168		break;
1169	case -ECONNREFUSED:
1170	case -ENOTCONN:
1171		rpc_force_rebind(clnt);
1172		task->tk_action = call_bind;
1173		break;
1174	case -EAGAIN:
1175		task->tk_action = call_transmit;
1176		break;
1177	case -EIO:
1178		/* shutdown or soft timeout */
1179		rpc_exit(task, status);
1180		break;
1181	default:
1182		printk("%s: RPC call returned error %d\n",
1183			       clnt->cl_protname, -status);
1184		rpc_exit(task, status);
1185	}
1186}
1187
1188/*
1189 * 6a.	Handle RPC timeout
1190 * 	We do not release the request slot, so we keep using the
1191 *	same XID for all retransmits.
1192 */
1193static void
1194call_timeout(struct rpc_task *task)
1195{
1196	struct rpc_clnt	*clnt = task->tk_client;
1197
1198	if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1199		dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1200		goto retry;
1201	}
1202
1203	dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1204	task->tk_timeouts++;
1205
1206	if (RPC_IS_SOFT(task)) {
1207		printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1208				clnt->cl_protname, clnt->cl_server);
1209		rpc_exit(task, -EIO);
1210		return;
1211	}
1212
1213	if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1214		task->tk_flags |= RPC_CALL_MAJORSEEN;
1215		printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1216			clnt->cl_protname, clnt->cl_server);
1217	}
1218	rpc_force_rebind(clnt);
1219
1220retry:
1221	clnt->cl_stats->rpcretrans++;
1222	task->tk_action = call_bind;
1223	task->tk_status = 0;
1224}
1225
1226/*
1227 * 7.	Decode the RPC reply
1228 */
1229static void
1230call_decode(struct rpc_task *task)
1231{
1232	struct rpc_clnt	*clnt = task->tk_client;
1233	struct rpc_rqst	*req = task->tk_rqstp;
1234	kxdrproc_t	decode = task->tk_msg.rpc_proc->p_decode;
1235	__be32		*p;
1236
1237	dprintk("RPC: %5u call_decode (status %d)\n",
1238			task->tk_pid, task->tk_status);
1239
1240	if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1241		printk(KERN_NOTICE "%s: server %s OK\n",
1242			clnt->cl_protname, clnt->cl_server);
1243		task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1244	}
1245
1246	if (task->tk_status < 12) {
1247		if (!RPC_IS_SOFT(task)) {
1248			task->tk_action = call_bind;
1249			clnt->cl_stats->rpcretrans++;
1250			goto out_retry;
1251		}
1252		dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1253				clnt->cl_protname, task->tk_status);
1254		task->tk_action = call_timeout;
1255		goto out_retry;
1256	}
1257
1258	/*
1259	 * Ensure that we see all writes made by xprt_complete_rqst()
1260	 * before it changed req->rq_received.
1261	 */
1262	smp_rmb();
1263	req->rq_rcv_buf.len = req->rq_private_buf.len;
1264
1265	/* Check that the softirq receive buffer is valid */
1266	WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1267				sizeof(req->rq_rcv_buf)) != 0);
1268
1269	/* Verify the RPC header */
1270	p = call_verify(task);
1271	if (IS_ERR(p)) {
1272		if (p == ERR_PTR(-EAGAIN))
1273			goto out_retry;
1274		return;
1275	}
1276
1277	task->tk_action = rpc_exit_task;
1278
1279	if (decode) {
1280		task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1281						      task->tk_msg.rpc_resp);
1282	}
1283	dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1284			task->tk_status);
1285	return;
1286out_retry:
1287	req->rq_received = req->rq_private_buf.len = 0;
1288	task->tk_status = 0;
1289	if (task->tk_client->cl_discrtry)
1290		xprt_force_disconnect(task->tk_xprt);
1291}
1292
1293/*
1294 * 8.	Refresh the credentials if rejected by the server
1295 */
1296static void
1297call_refresh(struct rpc_task *task)
1298{
1299	dprint_status(task);
1300
1301	task->tk_action = call_refreshresult;
1302	task->tk_status = 0;
1303	task->tk_client->cl_stats->rpcauthrefresh++;
1304	rpcauth_refreshcred(task);
1305}
1306
1307/*
1308 * 8a.	Process the results of a credential refresh
1309 */
1310static void
1311call_refreshresult(struct rpc_task *task)
1312{
1313	int status = task->tk_status;
1314
1315	dprint_status(task);
1316
1317	task->tk_status = 0;
1318	task->tk_action = call_reserve;
1319	if (status >= 0 && rpcauth_uptodatecred(task))
1320		return;
1321	if (status == -EACCES) {
1322		rpc_exit(task, -EACCES);
1323		return;
1324	}
1325	task->tk_action = call_refresh;
1326	if (status != -ETIMEDOUT)
1327		rpc_delay(task, 3*HZ);
1328	return;
1329}
1330
1331/*
1332 * Call header serialization
1333 */
1334static __be32 *
1335call_header(struct rpc_task *task)
1336{
1337	struct rpc_clnt *clnt = task->tk_client;
1338	struct rpc_rqst	*req = task->tk_rqstp;
1339	__be32		*p = req->rq_svec[0].iov_base;
1340
1341	/* FIXME: check buffer size? */
1342
1343	p = xprt_skip_transport_header(task->tk_xprt, p);
1344	*p++ = req->rq_xid;		/* XID */
1345	*p++ = htonl(RPC_CALL);		/* CALL */
1346	*p++ = htonl(RPC_VERSION);	/* RPC version */
1347	*p++ = htonl(clnt->cl_prog);	/* program number */
1348	*p++ = htonl(clnt->cl_vers);	/* program version */
1349	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */
1350	p = rpcauth_marshcred(task, p);
1351	req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1352	return p;
1353}
1354
1355/*
1356 * Reply header verification
1357 */
1358static __be32 *
1359call_verify(struct rpc_task *task)
1360{
1361	struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1362	int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1363	__be32	*p = iov->iov_base;
1364	u32 n;
1365	int error = -EACCES;
1366
1367	if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1368		/* RFC-1014 says that the representation of XDR data must be a
1369		 * multiple of four bytes
1370		 * - if it isn't pointer subtraction in the NFS client may give
1371		 *   undefined results
1372		 */
1373		dprintk("RPC: %5u %s: XDR representation not a multiple of"
1374		       " 4 bytes: 0x%x\n", task->tk_pid, __FUNCTION__,
1375		       task->tk_rqstp->rq_rcv_buf.len);
1376		goto out_eio;
1377	}
1378	if ((len -= 3) < 0)
1379		goto out_overflow;
1380	p += 1;	/* skip XID */
1381
1382	if ((n = ntohl(*p++)) != RPC_REPLY) {
1383		dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1384				task->tk_pid, __FUNCTION__, n);
1385		goto out_garbage;
1386	}
1387	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1388		if (--len < 0)
1389			goto out_overflow;
1390		switch ((n = ntohl(*p++))) {
1391			case RPC_AUTH_ERROR:
1392				break;
1393			case RPC_MISMATCH:
1394				dprintk("RPC: %5u %s: RPC call version "
1395						"mismatch!\n",
1396						task->tk_pid, __FUNCTION__);
1397				error = -EPROTONOSUPPORT;
1398				goto out_err;
1399			default:
1400				dprintk("RPC: %5u %s: RPC call rejected, "
1401						"unknown error: %x\n",
1402						task->tk_pid, __FUNCTION__, n);
1403				goto out_eio;
1404		}
1405		if (--len < 0)
1406			goto out_overflow;
1407		switch ((n = ntohl(*p++))) {
1408		case RPC_AUTH_REJECTEDCRED:
1409		case RPC_AUTH_REJECTEDVERF:
1410		case RPCSEC_GSS_CREDPROBLEM:
1411		case RPCSEC_GSS_CTXPROBLEM:
1412			if (!task->tk_cred_retry)
1413				break;
1414			task->tk_cred_retry--;
1415			dprintk("RPC: %5u %s: retry stale creds\n",
1416					task->tk_pid, __FUNCTION__);
1417			rpcauth_invalcred(task);
1418			/* Ensure we obtain a new XID! */
1419			xprt_release(task);
1420			task->tk_action = call_refresh;
1421			goto out_retry;
1422		case RPC_AUTH_BADCRED:
1423		case RPC_AUTH_BADVERF:
1424			/* possibly garbled cred/verf? */
1425			if (!task->tk_garb_retry)
1426				break;
1427			task->tk_garb_retry--;
1428			dprintk("RPC: %5u %s: retry garbled creds\n",
1429					task->tk_pid, __FUNCTION__);
1430			task->tk_action = call_bind;
1431			goto out_retry;
1432		case RPC_AUTH_TOOWEAK:
1433			printk(KERN_NOTICE "call_verify: server %s requires stronger "
1434			       "authentication.\n", task->tk_client->cl_server);
1435			break;
1436		default:
1437			dprintk("RPC: %5u %s: unknown auth error: %x\n",
1438					task->tk_pid, __FUNCTION__, n);
1439			error = -EIO;
1440		}
1441		dprintk("RPC: %5u %s: call rejected %d\n",
1442				task->tk_pid, __FUNCTION__, n);
1443		goto out_err;
1444	}
1445	if (!(p = rpcauth_checkverf(task, p))) {
1446		dprintk("RPC: %5u %s: auth check failed\n",
1447				task->tk_pid, __FUNCTION__);
1448		goto out_garbage;		/* bad verifier, retry */
1449	}
1450	len = p - (__be32 *)iov->iov_base - 1;
1451	if (len < 0)
1452		goto out_overflow;
1453	switch ((n = ntohl(*p++))) {
1454	case RPC_SUCCESS:
1455		return p;
1456	case RPC_PROG_UNAVAIL:
1457		dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1458				task->tk_pid, __FUNCTION__,
1459				(unsigned int)task->tk_client->cl_prog,
1460				task->tk_client->cl_server);
1461		error = -EPFNOSUPPORT;
1462		goto out_err;
1463	case RPC_PROG_MISMATCH:
1464		dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1465				"server %s\n", task->tk_pid, __FUNCTION__,
1466				(unsigned int)task->tk_client->cl_prog,
1467				(unsigned int)task->tk_client->cl_vers,
1468				task->tk_client->cl_server);
1469		error = -EPROTONOSUPPORT;
1470		goto out_err;
1471	case RPC_PROC_UNAVAIL:
1472		dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1473				"version %u on server %s\n",
1474				task->tk_pid, __FUNCTION__,
1475				task->tk_msg.rpc_proc,
1476				task->tk_client->cl_prog,
1477				task->tk_client->cl_vers,
1478				task->tk_client->cl_server);
1479		error = -EOPNOTSUPP;
1480		goto out_err;
1481	case RPC_GARBAGE_ARGS:
1482		dprintk("RPC: %5u %s: server saw garbage\n",
1483				task->tk_pid, __FUNCTION__);
1484		break;			/* retry */
1485	default:
1486		dprintk("RPC: %5u %s: server accept status: %x\n",
1487				task->tk_pid, __FUNCTION__, n);
1488		/* Also retry */
1489	}
1490
1491out_garbage:
1492	task->tk_client->cl_stats->rpcgarbage++;
1493	if (task->tk_garb_retry) {
1494		task->tk_garb_retry--;
1495		dprintk("RPC: %5u %s: retrying\n",
1496				task->tk_pid, __FUNCTION__);
1497		task->tk_action = call_bind;
1498out_retry:
1499		return ERR_PTR(-EAGAIN);
1500	}
1501out_eio:
1502	error = -EIO;
1503out_err:
1504	rpc_exit(task, error);
1505	dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1506			__FUNCTION__, error);
1507	return ERR_PTR(error);
1508out_overflow:
1509	dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1510			__FUNCTION__);
1511	goto out_garbage;
1512}
1513
1514static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1515{
1516	return 0;
1517}
1518
1519static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1520{
1521	return 0;
1522}
1523
1524static struct rpc_procinfo rpcproc_null = {
1525	.p_encode = rpcproc_encode_null,
1526	.p_decode = rpcproc_decode_null,
1527};
1528
1529static int rpc_ping(struct rpc_clnt *clnt, int flags)
1530{
1531	struct rpc_message msg = {
1532		.rpc_proc = &rpcproc_null,
1533	};
1534	int err;
1535	msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1536	err = rpc_call_sync(clnt, &msg, flags);
1537	put_rpccred(msg.rpc_cred);
1538	return err;
1539}
1540
1541struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1542{
1543	struct rpc_message msg = {
1544		.rpc_proc = &rpcproc_null,
1545		.rpc_cred = cred,
1546	};
1547	struct rpc_task_setup task_setup_data = {
1548		.rpc_client = clnt,
1549		.rpc_message = &msg,
1550		.callback_ops = &rpc_default_ops,
1551		.flags = flags,
1552	};
1553	return rpc_do_run_task(&task_setup_data);
1554}
1555EXPORT_SYMBOL_GPL(rpc_call_null);
1556
1557#ifdef RPC_DEBUG
1558void rpc_show_tasks(void)
1559{
1560	struct rpc_clnt *clnt;
1561	struct rpc_task *t;
1562
1563	spin_lock(&rpc_client_lock);
1564	if (list_empty(&all_clients))
1565		goto out;
1566	printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
1567		"-rpcwait -action- ---ops--\n");
1568	list_for_each_entry(clnt, &all_clients, cl_clients) {
1569		if (list_empty(&clnt->cl_tasks))
1570			continue;
1571		spin_lock(&clnt->cl_lock);
1572		list_for_each_entry(t, &clnt->cl_tasks, tk_task) {
1573			const char *rpc_waitq = "none";
1574			int proc;
1575
1576			if (t->tk_msg.rpc_proc)
1577				proc = t->tk_msg.rpc_proc->p_proc;
1578			else
1579				proc = -1;
1580
1581			if (RPC_IS_QUEUED(t))
1582				rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);
1583
1584			printk("%5u %04d %04x %6d %8p %6d %8p %8ld %8s %8p %8p\n",
1585				t->tk_pid, proc,
1586				t->tk_flags, t->tk_status,
1587				t->tk_client,
1588				(t->tk_client ? t->tk_client->cl_prog : 0),
1589				t->tk_rqstp, t->tk_timeout,
1590				rpc_waitq,
1591				t->tk_action, t->tk_ops);
1592		}
1593		spin_unlock(&clnt->cl_lock);
1594	}
1595out:
1596	spin_unlock(&rpc_client_lock);
1597}
1598#endif
1599