clnt.c revision e8914c65f7f8d4e8701b8e78a12b714872ea0402
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(struct rpc_clnt *clnt,
528		struct rpc_message *msg,
529		int flags,
530		const struct rpc_call_ops *ops,
531		void *data)
532{
533	struct rpc_task *task, *ret;
534	sigset_t oldset;
535
536	task = rpc_new_task(clnt, flags, ops, data);
537	if (task == NULL) {
538		rpc_release_calldata(ops, data);
539		return ERR_PTR(-ENOMEM);
540	}
541
542	/* Mask signals on synchronous RPC calls and RPCSEC_GSS upcalls */
543	rpc_task_sigmask(task, &oldset);
544	if (msg != NULL) {
545		rpc_call_setup(task, msg, 0);
546		if (task->tk_status != 0) {
547			ret = ERR_PTR(task->tk_status);
548			rpc_put_task(task);
549			goto out;
550		}
551	}
552	atomic_inc(&task->tk_count);
553	rpc_execute(task);
554	ret = task;
555out:
556	rpc_restore_sigmask(&oldset);
557	return ret;
558}
559
560/**
561 * rpc_call_sync - Perform a synchronous RPC call
562 * @clnt: pointer to RPC client
563 * @msg: RPC call parameters
564 * @flags: RPC call flags
565 */
566int rpc_call_sync(struct rpc_clnt *clnt, struct rpc_message *msg, int flags)
567{
568	struct rpc_task	*task;
569	int status;
570
571	BUG_ON(flags & RPC_TASK_ASYNC);
572
573	task = rpc_do_run_task(clnt, msg, flags, &rpc_default_ops, NULL);
574	if (IS_ERR(task))
575		return PTR_ERR(task);
576	status = task->tk_status;
577	rpc_put_task(task);
578	return status;
579}
580EXPORT_SYMBOL_GPL(rpc_call_sync);
581
582/**
583 * rpc_call_async - Perform an asynchronous RPC call
584 * @clnt: pointer to RPC client
585 * @msg: RPC call parameters
586 * @flags: RPC call flags
587 * @ops: RPC call ops
588 * @data: user call data
589 */
590int
591rpc_call_async(struct rpc_clnt *clnt, struct rpc_message *msg, int flags,
592	       const struct rpc_call_ops *tk_ops, void *data)
593{
594	struct rpc_task	*task;
595
596	task = rpc_do_run_task(clnt, msg, flags|RPC_TASK_ASYNC, tk_ops, data);
597	if (IS_ERR(task))
598		return PTR_ERR(task);
599	rpc_put_task(task);
600	return 0;
601}
602EXPORT_SYMBOL_GPL(rpc_call_async);
603
604/**
605 * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
606 * @clnt: pointer to RPC client
607 * @flags: RPC flags
608 * @ops: RPC call ops
609 * @data: user call data
610 */
611struct rpc_task *rpc_run_task(struct rpc_clnt *clnt, int flags,
612					const struct rpc_call_ops *tk_ops,
613					void *data)
614{
615	return rpc_do_run_task(clnt, NULL, flags, tk_ops, data);
616}
617EXPORT_SYMBOL_GPL(rpc_run_task);
618
619void
620rpc_call_setup(struct rpc_task *task, struct rpc_message *msg, int flags)
621{
622	task->tk_msg   = *msg;
623	task->tk_flags |= flags;
624	/* Bind the user cred */
625	if (task->tk_msg.rpc_cred != NULL)
626		rpcauth_holdcred(task);
627	else
628		rpcauth_bindcred(task);
629
630	if (task->tk_status == 0)
631		task->tk_action = call_start;
632	else
633		task->tk_action = rpc_exit_task;
634}
635EXPORT_SYMBOL_GPL(rpc_call_setup);
636
637/**
638 * rpc_peeraddr - extract remote peer address from clnt's xprt
639 * @clnt: RPC client structure
640 * @buf: target buffer
641 * @size: length of target buffer
642 *
643 * Returns the number of bytes that are actually in the stored address.
644 */
645size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
646{
647	size_t bytes;
648	struct rpc_xprt *xprt = clnt->cl_xprt;
649
650	bytes = sizeof(xprt->addr);
651	if (bytes > bufsize)
652		bytes = bufsize;
653	memcpy(buf, &clnt->cl_xprt->addr, bytes);
654	return xprt->addrlen;
655}
656EXPORT_SYMBOL_GPL(rpc_peeraddr);
657
658/**
659 * rpc_peeraddr2str - return remote peer address in printable format
660 * @clnt: RPC client structure
661 * @format: address format
662 *
663 */
664char *rpc_peeraddr2str(struct rpc_clnt *clnt, enum rpc_display_format_t format)
665{
666	struct rpc_xprt *xprt = clnt->cl_xprt;
667
668	if (xprt->address_strings[format] != NULL)
669		return xprt->address_strings[format];
670	else
671		return "unprintable";
672}
673EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
674
675void
676rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
677{
678	struct rpc_xprt *xprt = clnt->cl_xprt;
679	if (xprt->ops->set_buffer_size)
680		xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
681}
682EXPORT_SYMBOL_GPL(rpc_setbufsize);
683
684/*
685 * Return size of largest payload RPC client can support, in bytes
686 *
687 * For stream transports, this is one RPC record fragment (see RFC
688 * 1831), as we don't support multi-record requests yet.  For datagram
689 * transports, this is the size of an IP packet minus the IP, UDP, and
690 * RPC header sizes.
691 */
692size_t rpc_max_payload(struct rpc_clnt *clnt)
693{
694	return clnt->cl_xprt->max_payload;
695}
696EXPORT_SYMBOL_GPL(rpc_max_payload);
697
698/**
699 * rpc_force_rebind - force transport to check that remote port is unchanged
700 * @clnt: client to rebind
701 *
702 */
703void rpc_force_rebind(struct rpc_clnt *clnt)
704{
705	if (clnt->cl_autobind)
706		xprt_clear_bound(clnt->cl_xprt);
707}
708EXPORT_SYMBOL_GPL(rpc_force_rebind);
709
710/*
711 * Restart an (async) RPC call. Usually called from within the
712 * exit handler.
713 */
714void
715rpc_restart_call(struct rpc_task *task)
716{
717	if (RPC_ASSASSINATED(task))
718		return;
719
720	task->tk_action = call_start;
721}
722EXPORT_SYMBOL_GPL(rpc_restart_call);
723
724/*
725 * 0.  Initial state
726 *
727 *     Other FSM states can be visited zero or more times, but
728 *     this state is visited exactly once for each RPC.
729 */
730static void
731call_start(struct rpc_task *task)
732{
733	struct rpc_clnt	*clnt = task->tk_client;
734
735	dprintk("RPC: %5u call_start %s%d proc %d (%s)\n", task->tk_pid,
736			clnt->cl_protname, clnt->cl_vers,
737			task->tk_msg.rpc_proc->p_proc,
738			(RPC_IS_ASYNC(task) ? "async" : "sync"));
739
740	/* Increment call count */
741	task->tk_msg.rpc_proc->p_count++;
742	clnt->cl_stats->rpccnt++;
743	task->tk_action = call_reserve;
744}
745
746/*
747 * 1.	Reserve an RPC call slot
748 */
749static void
750call_reserve(struct rpc_task *task)
751{
752	dprint_status(task);
753
754	if (!rpcauth_uptodatecred(task)) {
755		task->tk_action = call_refresh;
756		return;
757	}
758
759	task->tk_status  = 0;
760	task->tk_action  = call_reserveresult;
761	xprt_reserve(task);
762}
763
764/*
765 * 1b.	Grok the result of xprt_reserve()
766 */
767static void
768call_reserveresult(struct rpc_task *task)
769{
770	int status = task->tk_status;
771
772	dprint_status(task);
773
774	/*
775	 * After a call to xprt_reserve(), we must have either
776	 * a request slot or else an error status.
777	 */
778	task->tk_status = 0;
779	if (status >= 0) {
780		if (task->tk_rqstp) {
781			task->tk_action = call_allocate;
782			return;
783		}
784
785		printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
786				__FUNCTION__, status);
787		rpc_exit(task, -EIO);
788		return;
789	}
790
791	/*
792	 * Even though there was an error, we may have acquired
793	 * a request slot somehow.  Make sure not to leak it.
794	 */
795	if (task->tk_rqstp) {
796		printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
797				__FUNCTION__, status);
798		xprt_release(task);
799	}
800
801	switch (status) {
802	case -EAGAIN:	/* woken up; retry */
803		task->tk_action = call_reserve;
804		return;
805	case -EIO:	/* probably a shutdown */
806		break;
807	default:
808		printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
809				__FUNCTION__, status);
810		break;
811	}
812	rpc_exit(task, status);
813}
814
815/*
816 * 2.	Allocate the buffer. For details, see sched.c:rpc_malloc.
817 *	(Note: buffer memory is freed in xprt_release).
818 */
819static void
820call_allocate(struct rpc_task *task)
821{
822	unsigned int slack = task->tk_msg.rpc_cred->cr_auth->au_cslack;
823	struct rpc_rqst *req = task->tk_rqstp;
824	struct rpc_xprt *xprt = task->tk_xprt;
825	struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
826
827	dprint_status(task);
828
829	task->tk_status = 0;
830	task->tk_action = call_bind;
831
832	if (req->rq_buffer)
833		return;
834
835	if (proc->p_proc != 0) {
836		BUG_ON(proc->p_arglen == 0);
837		if (proc->p_decode != NULL)
838			BUG_ON(proc->p_replen == 0);
839	}
840
841	/*
842	 * Calculate the size (in quads) of the RPC call
843	 * and reply headers, and convert both values
844	 * to byte sizes.
845	 */
846	req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
847	req->rq_callsize <<= 2;
848	req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
849	req->rq_rcvsize <<= 2;
850
851	req->rq_buffer = xprt->ops->buf_alloc(task,
852					req->rq_callsize + req->rq_rcvsize);
853	if (req->rq_buffer != NULL)
854		return;
855
856	dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
857
858	if (RPC_IS_ASYNC(task) || !signalled()) {
859		task->tk_action = call_allocate;
860		rpc_delay(task, HZ>>4);
861		return;
862	}
863
864	rpc_exit(task, -ERESTARTSYS);
865}
866
867static inline int
868rpc_task_need_encode(struct rpc_task *task)
869{
870	return task->tk_rqstp->rq_snd_buf.len == 0;
871}
872
873static inline void
874rpc_task_force_reencode(struct rpc_task *task)
875{
876	task->tk_rqstp->rq_snd_buf.len = 0;
877}
878
879static inline void
880rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
881{
882	buf->head[0].iov_base = start;
883	buf->head[0].iov_len = len;
884	buf->tail[0].iov_len = 0;
885	buf->page_len = 0;
886	buf->flags = 0;
887	buf->len = 0;
888	buf->buflen = len;
889}
890
891/*
892 * 3.	Encode arguments of an RPC call
893 */
894static void
895call_encode(struct rpc_task *task)
896{
897	struct rpc_rqst	*req = task->tk_rqstp;
898	kxdrproc_t	encode;
899	__be32		*p;
900
901	dprint_status(task);
902
903	rpc_xdr_buf_init(&req->rq_snd_buf,
904			 req->rq_buffer,
905			 req->rq_callsize);
906	rpc_xdr_buf_init(&req->rq_rcv_buf,
907			 (char *)req->rq_buffer + req->rq_callsize,
908			 req->rq_rcvsize);
909
910	/* Encode header and provided arguments */
911	encode = task->tk_msg.rpc_proc->p_encode;
912	if (!(p = call_header(task))) {
913		printk(KERN_INFO "RPC: call_header failed, exit EIO\n");
914		rpc_exit(task, -EIO);
915		return;
916	}
917	if (encode == NULL)
918		return;
919
920	task->tk_status = rpcauth_wrap_req(task, encode, req, p,
921			task->tk_msg.rpc_argp);
922	if (task->tk_status == -ENOMEM) {
923		/* XXX: Is this sane? */
924		rpc_delay(task, 3*HZ);
925		task->tk_status = -EAGAIN;
926	}
927}
928
929/*
930 * 4.	Get the server port number if not yet set
931 */
932static void
933call_bind(struct rpc_task *task)
934{
935	struct rpc_xprt *xprt = task->tk_xprt;
936
937	dprint_status(task);
938
939	task->tk_action = call_connect;
940	if (!xprt_bound(xprt)) {
941		task->tk_action = call_bind_status;
942		task->tk_timeout = xprt->bind_timeout;
943		xprt->ops->rpcbind(task);
944	}
945}
946
947/*
948 * 4a.	Sort out bind result
949 */
950static void
951call_bind_status(struct rpc_task *task)
952{
953	int status = -EIO;
954
955	if (task->tk_status >= 0) {
956		dprint_status(task);
957		task->tk_status = 0;
958		task->tk_action = call_connect;
959		return;
960	}
961
962	switch (task->tk_status) {
963	case -EAGAIN:
964		dprintk("RPC: %5u rpcbind waiting for another request "
965				"to finish\n", task->tk_pid);
966		/* avoid busy-waiting here -- could be a network outage. */
967		rpc_delay(task, 5*HZ);
968		goto retry_timeout;
969	case -EACCES:
970		dprintk("RPC: %5u remote rpcbind: RPC program/version "
971				"unavailable\n", task->tk_pid);
972		/* fail immediately if this is an RPC ping */
973		if (task->tk_msg.rpc_proc->p_proc == 0) {
974			status = -EOPNOTSUPP;
975			break;
976		}
977		rpc_delay(task, 3*HZ);
978		goto retry_timeout;
979	case -ETIMEDOUT:
980		dprintk("RPC: %5u rpcbind request timed out\n",
981				task->tk_pid);
982		goto retry_timeout;
983	case -EPFNOSUPPORT:
984		/* server doesn't support any rpcbind version we know of */
985		dprintk("RPC: %5u remote rpcbind service unavailable\n",
986				task->tk_pid);
987		break;
988	case -EPROTONOSUPPORT:
989		dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
990				task->tk_pid);
991		task->tk_status = 0;
992		task->tk_action = call_bind;
993		return;
994	default:
995		dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
996				task->tk_pid, -task->tk_status);
997	}
998
999	rpc_exit(task, status);
1000	return;
1001
1002retry_timeout:
1003	task->tk_action = call_timeout;
1004}
1005
1006/*
1007 * 4b.	Connect to the RPC server
1008 */
1009static void
1010call_connect(struct rpc_task *task)
1011{
1012	struct rpc_xprt *xprt = task->tk_xprt;
1013
1014	dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1015			task->tk_pid, xprt,
1016			(xprt_connected(xprt) ? "is" : "is not"));
1017
1018	task->tk_action = call_transmit;
1019	if (!xprt_connected(xprt)) {
1020		task->tk_action = call_connect_status;
1021		if (task->tk_status < 0)
1022			return;
1023		xprt_connect(task);
1024	}
1025}
1026
1027/*
1028 * 4c.	Sort out connect result
1029 */
1030static void
1031call_connect_status(struct rpc_task *task)
1032{
1033	struct rpc_clnt *clnt = task->tk_client;
1034	int status = task->tk_status;
1035
1036	dprint_status(task);
1037
1038	task->tk_status = 0;
1039	if (status >= 0) {
1040		clnt->cl_stats->netreconn++;
1041		task->tk_action = call_transmit;
1042		return;
1043	}
1044
1045	/* Something failed: remote service port may have changed */
1046	rpc_force_rebind(clnt);
1047
1048	switch (status) {
1049	case -ENOTCONN:
1050	case -EAGAIN:
1051		task->tk_action = call_bind;
1052		if (!RPC_IS_SOFT(task))
1053			return;
1054		/* if soft mounted, test if we've timed out */
1055	case -ETIMEDOUT:
1056		task->tk_action = call_timeout;
1057		return;
1058	}
1059	rpc_exit(task, -EIO);
1060}
1061
1062/*
1063 * 5.	Transmit the RPC request, and wait for reply
1064 */
1065static void
1066call_transmit(struct rpc_task *task)
1067{
1068	dprint_status(task);
1069
1070	task->tk_action = call_status;
1071	if (task->tk_status < 0)
1072		return;
1073	task->tk_status = xprt_prepare_transmit(task);
1074	if (task->tk_status != 0)
1075		return;
1076	task->tk_action = call_transmit_status;
1077	/* Encode here so that rpcsec_gss can use correct sequence number. */
1078	if (rpc_task_need_encode(task)) {
1079		BUG_ON(task->tk_rqstp->rq_bytes_sent != 0);
1080		call_encode(task);
1081		/* Did the encode result in an error condition? */
1082		if (task->tk_status != 0)
1083			return;
1084	}
1085	xprt_transmit(task);
1086	if (task->tk_status < 0)
1087		return;
1088	/*
1089	 * On success, ensure that we call xprt_end_transmit() before sleeping
1090	 * in order to allow access to the socket to other RPC requests.
1091	 */
1092	call_transmit_status(task);
1093	if (task->tk_msg.rpc_proc->p_decode != NULL)
1094		return;
1095	task->tk_action = rpc_exit_task;
1096	rpc_wake_up_task(task);
1097}
1098
1099/*
1100 * 5a.	Handle cleanup after a transmission
1101 */
1102static void
1103call_transmit_status(struct rpc_task *task)
1104{
1105	task->tk_action = call_status;
1106	/*
1107	 * Special case: if we've been waiting on the socket's write_space()
1108	 * callback, then don't call xprt_end_transmit().
1109	 */
1110	if (task->tk_status == -EAGAIN)
1111		return;
1112	xprt_end_transmit(task);
1113	rpc_task_force_reencode(task);
1114}
1115
1116/*
1117 * 6.	Sort out the RPC call status
1118 */
1119static void
1120call_status(struct rpc_task *task)
1121{
1122	struct rpc_clnt	*clnt = task->tk_client;
1123	struct rpc_rqst	*req = task->tk_rqstp;
1124	int		status;
1125
1126	if (req->rq_received > 0 && !req->rq_bytes_sent)
1127		task->tk_status = req->rq_received;
1128
1129	dprint_status(task);
1130
1131	status = task->tk_status;
1132	if (status >= 0) {
1133		task->tk_action = call_decode;
1134		return;
1135	}
1136
1137	task->tk_status = 0;
1138	switch(status) {
1139	case -EHOSTDOWN:
1140	case -EHOSTUNREACH:
1141	case -ENETUNREACH:
1142		/*
1143		 * Delay any retries for 3 seconds, then handle as if it
1144		 * were a timeout.
1145		 */
1146		rpc_delay(task, 3*HZ);
1147	case -ETIMEDOUT:
1148		task->tk_action = call_timeout;
1149		if (task->tk_client->cl_discrtry)
1150			xprt_force_disconnect(task->tk_xprt);
1151		break;
1152	case -ECONNREFUSED:
1153	case -ENOTCONN:
1154		rpc_force_rebind(clnt);
1155		task->tk_action = call_bind;
1156		break;
1157	case -EAGAIN:
1158		task->tk_action = call_transmit;
1159		break;
1160	case -EIO:
1161		/* shutdown or soft timeout */
1162		rpc_exit(task, status);
1163		break;
1164	default:
1165		printk("%s: RPC call returned error %d\n",
1166			       clnt->cl_protname, -status);
1167		rpc_exit(task, status);
1168	}
1169}
1170
1171/*
1172 * 6a.	Handle RPC timeout
1173 * 	We do not release the request slot, so we keep using the
1174 *	same XID for all retransmits.
1175 */
1176static void
1177call_timeout(struct rpc_task *task)
1178{
1179	struct rpc_clnt	*clnt = task->tk_client;
1180
1181	if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1182		dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1183		goto retry;
1184	}
1185
1186	dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1187	task->tk_timeouts++;
1188
1189	if (RPC_IS_SOFT(task)) {
1190		printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1191				clnt->cl_protname, clnt->cl_server);
1192		rpc_exit(task, -EIO);
1193		return;
1194	}
1195
1196	if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1197		task->tk_flags |= RPC_CALL_MAJORSEEN;
1198		printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1199			clnt->cl_protname, clnt->cl_server);
1200	}
1201	rpc_force_rebind(clnt);
1202
1203retry:
1204	clnt->cl_stats->rpcretrans++;
1205	task->tk_action = call_bind;
1206	task->tk_status = 0;
1207}
1208
1209/*
1210 * 7.	Decode the RPC reply
1211 */
1212static void
1213call_decode(struct rpc_task *task)
1214{
1215	struct rpc_clnt	*clnt = task->tk_client;
1216	struct rpc_rqst	*req = task->tk_rqstp;
1217	kxdrproc_t	decode = task->tk_msg.rpc_proc->p_decode;
1218	__be32		*p;
1219
1220	dprintk("RPC: %5u call_decode (status %d)\n",
1221			task->tk_pid, task->tk_status);
1222
1223	if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1224		printk(KERN_NOTICE "%s: server %s OK\n",
1225			clnt->cl_protname, clnt->cl_server);
1226		task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1227	}
1228
1229	if (task->tk_status < 12) {
1230		if (!RPC_IS_SOFT(task)) {
1231			task->tk_action = call_bind;
1232			clnt->cl_stats->rpcretrans++;
1233			goto out_retry;
1234		}
1235		dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1236				clnt->cl_protname, task->tk_status);
1237		task->tk_action = call_timeout;
1238		goto out_retry;
1239	}
1240
1241	/*
1242	 * Ensure that we see all writes made by xprt_complete_rqst()
1243	 * before it changed req->rq_received.
1244	 */
1245	smp_rmb();
1246	req->rq_rcv_buf.len = req->rq_private_buf.len;
1247
1248	/* Check that the softirq receive buffer is valid */
1249	WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1250				sizeof(req->rq_rcv_buf)) != 0);
1251
1252	/* Verify the RPC header */
1253	p = call_verify(task);
1254	if (IS_ERR(p)) {
1255		if (p == ERR_PTR(-EAGAIN))
1256			goto out_retry;
1257		return;
1258	}
1259
1260	task->tk_action = rpc_exit_task;
1261
1262	if (decode) {
1263		task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1264						      task->tk_msg.rpc_resp);
1265	}
1266	dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1267			task->tk_status);
1268	return;
1269out_retry:
1270	req->rq_received = req->rq_private_buf.len = 0;
1271	task->tk_status = 0;
1272	if (task->tk_client->cl_discrtry)
1273		xprt_force_disconnect(task->tk_xprt);
1274}
1275
1276/*
1277 * 8.	Refresh the credentials if rejected by the server
1278 */
1279static void
1280call_refresh(struct rpc_task *task)
1281{
1282	dprint_status(task);
1283
1284	task->tk_action = call_refreshresult;
1285	task->tk_status = 0;
1286	task->tk_client->cl_stats->rpcauthrefresh++;
1287	rpcauth_refreshcred(task);
1288}
1289
1290/*
1291 * 8a.	Process the results of a credential refresh
1292 */
1293static void
1294call_refreshresult(struct rpc_task *task)
1295{
1296	int status = task->tk_status;
1297
1298	dprint_status(task);
1299
1300	task->tk_status = 0;
1301	task->tk_action = call_reserve;
1302	if (status >= 0 && rpcauth_uptodatecred(task))
1303		return;
1304	if (status == -EACCES) {
1305		rpc_exit(task, -EACCES);
1306		return;
1307	}
1308	task->tk_action = call_refresh;
1309	if (status != -ETIMEDOUT)
1310		rpc_delay(task, 3*HZ);
1311	return;
1312}
1313
1314/*
1315 * Call header serialization
1316 */
1317static __be32 *
1318call_header(struct rpc_task *task)
1319{
1320	struct rpc_clnt *clnt = task->tk_client;
1321	struct rpc_rqst	*req = task->tk_rqstp;
1322	__be32		*p = req->rq_svec[0].iov_base;
1323
1324	/* FIXME: check buffer size? */
1325
1326	p = xprt_skip_transport_header(task->tk_xprt, p);
1327	*p++ = req->rq_xid;		/* XID */
1328	*p++ = htonl(RPC_CALL);		/* CALL */
1329	*p++ = htonl(RPC_VERSION);	/* RPC version */
1330	*p++ = htonl(clnt->cl_prog);	/* program number */
1331	*p++ = htonl(clnt->cl_vers);	/* program version */
1332	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */
1333	p = rpcauth_marshcred(task, p);
1334	req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
1335	return p;
1336}
1337
1338/*
1339 * Reply header verification
1340 */
1341static __be32 *
1342call_verify(struct rpc_task *task)
1343{
1344	struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
1345	int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
1346	__be32	*p = iov->iov_base;
1347	u32 n;
1348	int error = -EACCES;
1349
1350	if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
1351		/* RFC-1014 says that the representation of XDR data must be a
1352		 * multiple of four bytes
1353		 * - if it isn't pointer subtraction in the NFS client may give
1354		 *   undefined results
1355		 */
1356		dprintk("RPC: %5u %s: XDR representation not a multiple of"
1357		       " 4 bytes: 0x%x\n", task->tk_pid, __FUNCTION__,
1358		       task->tk_rqstp->rq_rcv_buf.len);
1359		goto out_eio;
1360	}
1361	if ((len -= 3) < 0)
1362		goto out_overflow;
1363	p += 1;	/* skip XID */
1364
1365	if ((n = ntohl(*p++)) != RPC_REPLY) {
1366		dprintk("RPC: %5u %s: not an RPC reply: %x\n",
1367				task->tk_pid, __FUNCTION__, n);
1368		goto out_garbage;
1369	}
1370	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
1371		if (--len < 0)
1372			goto out_overflow;
1373		switch ((n = ntohl(*p++))) {
1374			case RPC_AUTH_ERROR:
1375				break;
1376			case RPC_MISMATCH:
1377				dprintk("RPC: %5u %s: RPC call version "
1378						"mismatch!\n",
1379						task->tk_pid, __FUNCTION__);
1380				error = -EPROTONOSUPPORT;
1381				goto out_err;
1382			default:
1383				dprintk("RPC: %5u %s: RPC call rejected, "
1384						"unknown error: %x\n",
1385						task->tk_pid, __FUNCTION__, n);
1386				goto out_eio;
1387		}
1388		if (--len < 0)
1389			goto out_overflow;
1390		switch ((n = ntohl(*p++))) {
1391		case RPC_AUTH_REJECTEDCRED:
1392		case RPC_AUTH_REJECTEDVERF:
1393		case RPCSEC_GSS_CREDPROBLEM:
1394		case RPCSEC_GSS_CTXPROBLEM:
1395			if (!task->tk_cred_retry)
1396				break;
1397			task->tk_cred_retry--;
1398			dprintk("RPC: %5u %s: retry stale creds\n",
1399					task->tk_pid, __FUNCTION__);
1400			rpcauth_invalcred(task);
1401			/* Ensure we obtain a new XID! */
1402			xprt_release(task);
1403			task->tk_action = call_refresh;
1404			goto out_retry;
1405		case RPC_AUTH_BADCRED:
1406		case RPC_AUTH_BADVERF:
1407			/* possibly garbled cred/verf? */
1408			if (!task->tk_garb_retry)
1409				break;
1410			task->tk_garb_retry--;
1411			dprintk("RPC: %5u %s: retry garbled creds\n",
1412					task->tk_pid, __FUNCTION__);
1413			task->tk_action = call_bind;
1414			goto out_retry;
1415		case RPC_AUTH_TOOWEAK:
1416			printk(KERN_NOTICE "call_verify: server %s requires stronger "
1417			       "authentication.\n", task->tk_client->cl_server);
1418			break;
1419		default:
1420			dprintk("RPC: %5u %s: unknown auth error: %x\n",
1421					task->tk_pid, __FUNCTION__, n);
1422			error = -EIO;
1423		}
1424		dprintk("RPC: %5u %s: call rejected %d\n",
1425				task->tk_pid, __FUNCTION__, n);
1426		goto out_err;
1427	}
1428	if (!(p = rpcauth_checkverf(task, p))) {
1429		dprintk("RPC: %5u %s: auth check failed\n",
1430				task->tk_pid, __FUNCTION__);
1431		goto out_garbage;		/* bad verifier, retry */
1432	}
1433	len = p - (__be32 *)iov->iov_base - 1;
1434	if (len < 0)
1435		goto out_overflow;
1436	switch ((n = ntohl(*p++))) {
1437	case RPC_SUCCESS:
1438		return p;
1439	case RPC_PROG_UNAVAIL:
1440		dprintk("RPC: %5u %s: program %u is unsupported by server %s\n",
1441				task->tk_pid, __FUNCTION__,
1442				(unsigned int)task->tk_client->cl_prog,
1443				task->tk_client->cl_server);
1444		error = -EPFNOSUPPORT;
1445		goto out_err;
1446	case RPC_PROG_MISMATCH:
1447		dprintk("RPC: %5u %s: program %u, version %u unsupported by "
1448				"server %s\n", task->tk_pid, __FUNCTION__,
1449				(unsigned int)task->tk_client->cl_prog,
1450				(unsigned int)task->tk_client->cl_vers,
1451				task->tk_client->cl_server);
1452		error = -EPROTONOSUPPORT;
1453		goto out_err;
1454	case RPC_PROC_UNAVAIL:
1455		dprintk("RPC: %5u %s: proc %p unsupported by program %u, "
1456				"version %u on server %s\n",
1457				task->tk_pid, __FUNCTION__,
1458				task->tk_msg.rpc_proc,
1459				task->tk_client->cl_prog,
1460				task->tk_client->cl_vers,
1461				task->tk_client->cl_server);
1462		error = -EOPNOTSUPP;
1463		goto out_err;
1464	case RPC_GARBAGE_ARGS:
1465		dprintk("RPC: %5u %s: server saw garbage\n",
1466				task->tk_pid, __FUNCTION__);
1467		break;			/* retry */
1468	default:
1469		dprintk("RPC: %5u %s: server accept status: %x\n",
1470				task->tk_pid, __FUNCTION__, n);
1471		/* Also retry */
1472	}
1473
1474out_garbage:
1475	task->tk_client->cl_stats->rpcgarbage++;
1476	if (task->tk_garb_retry) {
1477		task->tk_garb_retry--;
1478		dprintk("RPC: %5u %s: retrying\n",
1479				task->tk_pid, __FUNCTION__);
1480		task->tk_action = call_bind;
1481out_retry:
1482		return ERR_PTR(-EAGAIN);
1483	}
1484out_eio:
1485	error = -EIO;
1486out_err:
1487	rpc_exit(task, error);
1488	dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
1489			__FUNCTION__, error);
1490	return ERR_PTR(error);
1491out_overflow:
1492	dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
1493			__FUNCTION__);
1494	goto out_garbage;
1495}
1496
1497static int rpcproc_encode_null(void *rqstp, __be32 *data, void *obj)
1498{
1499	return 0;
1500}
1501
1502static int rpcproc_decode_null(void *rqstp, __be32 *data, void *obj)
1503{
1504	return 0;
1505}
1506
1507static struct rpc_procinfo rpcproc_null = {
1508	.p_encode = rpcproc_encode_null,
1509	.p_decode = rpcproc_decode_null,
1510};
1511
1512static int rpc_ping(struct rpc_clnt *clnt, int flags)
1513{
1514	struct rpc_message msg = {
1515		.rpc_proc = &rpcproc_null,
1516	};
1517	int err;
1518	msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
1519	err = rpc_call_sync(clnt, &msg, flags);
1520	put_rpccred(msg.rpc_cred);
1521	return err;
1522}
1523
1524struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
1525{
1526	struct rpc_message msg = {
1527		.rpc_proc = &rpcproc_null,
1528		.rpc_cred = cred,
1529	};
1530	return rpc_do_run_task(clnt, &msg, flags, &rpc_default_ops, NULL);
1531}
1532EXPORT_SYMBOL_GPL(rpc_call_null);
1533
1534#ifdef RPC_DEBUG
1535void rpc_show_tasks(void)
1536{
1537	struct rpc_clnt *clnt;
1538	struct rpc_task *t;
1539
1540	spin_lock(&rpc_client_lock);
1541	if (list_empty(&all_clients))
1542		goto out;
1543	printk("-pid- proc flgs status -client- -prog- --rqstp- -timeout "
1544		"-rpcwait -action- ---ops--\n");
1545	list_for_each_entry(clnt, &all_clients, cl_clients) {
1546		if (list_empty(&clnt->cl_tasks))
1547			continue;
1548		spin_lock(&clnt->cl_lock);
1549		list_for_each_entry(t, &clnt->cl_tasks, tk_task) {
1550			const char *rpc_waitq = "none";
1551			int proc;
1552
1553			if (t->tk_msg.rpc_proc)
1554				proc = t->tk_msg.rpc_proc->p_proc;
1555			else
1556				proc = -1;
1557
1558			if (RPC_IS_QUEUED(t))
1559				rpc_waitq = rpc_qname(t->u.tk_wait.rpc_waitq);
1560
1561			printk("%5u %04d %04x %6d %8p %6d %8p %8ld %8s %8p %8p\n",
1562				t->tk_pid, proc,
1563				t->tk_flags, t->tk_status,
1564				t->tk_client,
1565				(t->tk_client ? t->tk_client->cl_prog : 0),
1566				t->tk_rqstp, t->tk_timeout,
1567				rpc_waitq,
1568				t->tk_action, t->tk_ops);
1569		}
1570		spin_unlock(&clnt->cl_lock);
1571	}
1572out:
1573	spin_unlock(&rpc_client_lock);
1574}
1575#endif
1576