xref: /linux/net/sunrpc/clnt.c (revision c75c5ab575af7db707689cdbb5a5c458e9a034bb)
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  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
17  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
18  */
19 
20 
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/kallsyms.h>
24 #include <linux/mm.h>
25 #include <linux/namei.h>
26 #include <linux/mount.h>
27 #include <linux/slab.h>
28 #include <linux/utsname.h>
29 #include <linux/workqueue.h>
30 #include <linux/in.h>
31 #include <linux/in6.h>
32 #include <linux/un.h>
33 #include <linux/rcupdate.h>
34 
35 #include <linux/sunrpc/clnt.h>
36 #include <linux/sunrpc/addr.h>
37 #include <linux/sunrpc/rpc_pipe_fs.h>
38 #include <linux/sunrpc/metrics.h>
39 #include <linux/sunrpc/bc_xprt.h>
40 #include <trace/events/sunrpc.h>
41 
42 #include "sunrpc.h"
43 #include "netns.h"
44 
45 #ifdef RPC_DEBUG
46 # define RPCDBG_FACILITY	RPCDBG_CALL
47 #endif
48 
49 #define dprint_status(t)					\
50 	dprintk("RPC: %5u %s (status %d)\n", t->tk_pid,		\
51 			__func__, t->tk_status)
52 
53 /*
54  * All RPC clients are linked into this list
55  */
56 
57 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
58 
59 
60 static void	call_start(struct rpc_task *task);
61 static void	call_reserve(struct rpc_task *task);
62 static void	call_reserveresult(struct rpc_task *task);
63 static void	call_allocate(struct rpc_task *task);
64 static void	call_decode(struct rpc_task *task);
65 static void	call_bind(struct rpc_task *task);
66 static void	call_bind_status(struct rpc_task *task);
67 static void	call_transmit(struct rpc_task *task);
68 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
69 static void	call_bc_transmit(struct rpc_task *task);
70 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
71 static void	call_status(struct rpc_task *task);
72 static void	call_transmit_status(struct rpc_task *task);
73 static void	call_refresh(struct rpc_task *task);
74 static void	call_refreshresult(struct rpc_task *task);
75 static void	call_timeout(struct rpc_task *task);
76 static void	call_connect(struct rpc_task *task);
77 static void	call_connect_status(struct rpc_task *task);
78 
79 static __be32	*rpc_encode_header(struct rpc_task *task);
80 static __be32	*rpc_verify_header(struct rpc_task *task);
81 static int	rpc_ping(struct rpc_clnt *clnt);
82 
83 static void rpc_register_client(struct rpc_clnt *clnt)
84 {
85 	struct net *net = rpc_net_ns(clnt);
86 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
87 
88 	spin_lock(&sn->rpc_client_lock);
89 	list_add(&clnt->cl_clients, &sn->all_clients);
90 	spin_unlock(&sn->rpc_client_lock);
91 }
92 
93 static void rpc_unregister_client(struct rpc_clnt *clnt)
94 {
95 	struct net *net = rpc_net_ns(clnt);
96 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
97 
98 	spin_lock(&sn->rpc_client_lock);
99 	list_del(&clnt->cl_clients);
100 	spin_unlock(&sn->rpc_client_lock);
101 }
102 
103 static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
104 {
105 	if (clnt->cl_dentry) {
106 		if (clnt->cl_auth && clnt->cl_auth->au_ops->pipes_destroy)
107 			clnt->cl_auth->au_ops->pipes_destroy(clnt->cl_auth);
108 		rpc_remove_client_dir(clnt->cl_dentry);
109 	}
110 	clnt->cl_dentry = NULL;
111 }
112 
113 static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
114 {
115 	struct net *net = rpc_net_ns(clnt);
116 	struct super_block *pipefs_sb;
117 
118 	pipefs_sb = rpc_get_sb_net(net);
119 	if (pipefs_sb) {
120 		__rpc_clnt_remove_pipedir(clnt);
121 		rpc_put_sb_net(net);
122 	}
123 }
124 
125 static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
126 				    struct rpc_clnt *clnt,
127 				    const char *dir_name)
128 {
129 	static uint32_t clntid;
130 	char name[15];
131 	struct qstr q = { .name = name };
132 	struct dentry *dir, *dentry;
133 	int error;
134 
135 	dir = rpc_d_lookup_sb(sb, dir_name);
136 	if (dir == NULL) {
137 		pr_info("RPC: pipefs directory doesn't exist: %s\n", dir_name);
138 		return dir;
139 	}
140 	for (;;) {
141 		q.len = snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
142 		name[sizeof(name) - 1] = '\0';
143 		q.hash = full_name_hash(q.name, q.len);
144 		dentry = rpc_create_client_dir(dir, &q, clnt);
145 		if (!IS_ERR(dentry))
146 			break;
147 		error = PTR_ERR(dentry);
148 		if (error != -EEXIST) {
149 			printk(KERN_INFO "RPC: Couldn't create pipefs entry"
150 					" %s/%s, error %d\n",
151 					dir_name, name, error);
152 			break;
153 		}
154 	}
155 	dput(dir);
156 	return dentry;
157 }
158 
159 static int
160 rpc_setup_pipedir(struct rpc_clnt *clnt, const char *dir_name)
161 {
162 	struct net *net = rpc_net_ns(clnt);
163 	struct super_block *pipefs_sb;
164 	struct dentry *dentry;
165 
166 	clnt->cl_dentry = NULL;
167 	if (dir_name == NULL)
168 		return 0;
169 	pipefs_sb = rpc_get_sb_net(net);
170 	if (!pipefs_sb)
171 		return 0;
172 	dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt, dir_name);
173 	rpc_put_sb_net(net);
174 	if (IS_ERR(dentry))
175 		return PTR_ERR(dentry);
176 	clnt->cl_dentry = dentry;
177 	return 0;
178 }
179 
180 static inline int rpc_clnt_skip_event(struct rpc_clnt *clnt, unsigned long event)
181 {
182 	if (((event == RPC_PIPEFS_MOUNT) && clnt->cl_dentry) ||
183 	    ((event == RPC_PIPEFS_UMOUNT) && !clnt->cl_dentry))
184 		return 1;
185 	return 0;
186 }
187 
188 static int __rpc_clnt_handle_event(struct rpc_clnt *clnt, unsigned long event,
189 				   struct super_block *sb)
190 {
191 	struct dentry *dentry;
192 	int err = 0;
193 
194 	switch (event) {
195 	case RPC_PIPEFS_MOUNT:
196 		dentry = rpc_setup_pipedir_sb(sb, clnt,
197 					      clnt->cl_program->pipe_dir_name);
198 		if (!dentry)
199 			return -ENOENT;
200 		if (IS_ERR(dentry))
201 			return PTR_ERR(dentry);
202 		clnt->cl_dentry = dentry;
203 		if (clnt->cl_auth->au_ops->pipes_create) {
204 			err = clnt->cl_auth->au_ops->pipes_create(clnt->cl_auth);
205 			if (err)
206 				__rpc_clnt_remove_pipedir(clnt);
207 		}
208 		break;
209 	case RPC_PIPEFS_UMOUNT:
210 		__rpc_clnt_remove_pipedir(clnt);
211 		break;
212 	default:
213 		printk(KERN_ERR "%s: unknown event: %ld\n", __func__, event);
214 		return -ENOTSUPP;
215 	}
216 	return err;
217 }
218 
219 static int __rpc_pipefs_event(struct rpc_clnt *clnt, unsigned long event,
220 				struct super_block *sb)
221 {
222 	int error = 0;
223 
224 	for (;; clnt = clnt->cl_parent) {
225 		if (!rpc_clnt_skip_event(clnt, event))
226 			error = __rpc_clnt_handle_event(clnt, event, sb);
227 		if (error || clnt == clnt->cl_parent)
228 			break;
229 	}
230 	return error;
231 }
232 
233 static struct rpc_clnt *rpc_get_client_for_event(struct net *net, int event)
234 {
235 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
236 	struct rpc_clnt *clnt;
237 
238 	spin_lock(&sn->rpc_client_lock);
239 	list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
240 		if (clnt->cl_program->pipe_dir_name == NULL)
241 			continue;
242 		if (rpc_clnt_skip_event(clnt, event))
243 			continue;
244 		if (atomic_inc_not_zero(&clnt->cl_count) == 0)
245 			continue;
246 		spin_unlock(&sn->rpc_client_lock);
247 		return clnt;
248 	}
249 	spin_unlock(&sn->rpc_client_lock);
250 	return NULL;
251 }
252 
253 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
254 			    void *ptr)
255 {
256 	struct super_block *sb = ptr;
257 	struct rpc_clnt *clnt;
258 	int error = 0;
259 
260 	while ((clnt = rpc_get_client_for_event(sb->s_fs_info, event))) {
261 		error = __rpc_pipefs_event(clnt, event, sb);
262 		rpc_release_client(clnt);
263 		if (error)
264 			break;
265 	}
266 	return error;
267 }
268 
269 static struct notifier_block rpc_clients_block = {
270 	.notifier_call	= rpc_pipefs_event,
271 	.priority	= SUNRPC_PIPEFS_RPC_PRIO,
272 };
273 
274 int rpc_clients_notifier_register(void)
275 {
276 	return rpc_pipefs_notifier_register(&rpc_clients_block);
277 }
278 
279 void rpc_clients_notifier_unregister(void)
280 {
281 	return rpc_pipefs_notifier_unregister(&rpc_clients_block);
282 }
283 
284 static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename)
285 {
286 	clnt->cl_nodelen = strlen(nodename);
287 	if (clnt->cl_nodelen > UNX_MAXNODENAME)
288 		clnt->cl_nodelen = UNX_MAXNODENAME;
289 	memcpy(clnt->cl_nodename, nodename, clnt->cl_nodelen);
290 }
291 
292 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args, struct rpc_xprt *xprt)
293 {
294 	const struct rpc_program *program = args->program;
295 	const struct rpc_version *version;
296 	struct rpc_clnt		*clnt = NULL;
297 	struct rpc_auth		*auth;
298 	int err;
299 
300 	/* sanity check the name before trying to print it */
301 	dprintk("RPC:       creating %s client for %s (xprt %p)\n",
302 			program->name, args->servername, xprt);
303 
304 	err = rpciod_up();
305 	if (err)
306 		goto out_no_rpciod;
307 
308 	err = -EINVAL;
309 	if (args->version >= program->nrvers)
310 		goto out_err;
311 	version = program->version[args->version];
312 	if (version == NULL)
313 		goto out_err;
314 
315 	err = -ENOMEM;
316 	clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
317 	if (!clnt)
318 		goto out_err;
319 	clnt->cl_parent = clnt;
320 
321 	rcu_assign_pointer(clnt->cl_xprt, xprt);
322 	clnt->cl_procinfo = version->procs;
323 	clnt->cl_maxproc  = version->nrprocs;
324 	clnt->cl_protname = program->name;
325 	clnt->cl_prog     = args->prognumber ? : program->number;
326 	clnt->cl_vers     = version->number;
327 	clnt->cl_stats    = program->stats;
328 	clnt->cl_metrics  = rpc_alloc_iostats(clnt);
329 	err = -ENOMEM;
330 	if (clnt->cl_metrics == NULL)
331 		goto out_no_stats;
332 	clnt->cl_program  = program;
333 	INIT_LIST_HEAD(&clnt->cl_tasks);
334 	spin_lock_init(&clnt->cl_lock);
335 
336 	if (!xprt_bound(xprt))
337 		clnt->cl_autobind = 1;
338 
339 	clnt->cl_timeout = xprt->timeout;
340 	if (args->timeout != NULL) {
341 		memcpy(&clnt->cl_timeout_default, args->timeout,
342 				sizeof(clnt->cl_timeout_default));
343 		clnt->cl_timeout = &clnt->cl_timeout_default;
344 	}
345 
346 	clnt->cl_rtt = &clnt->cl_rtt_default;
347 	rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
348 	clnt->cl_principal = NULL;
349 	if (args->client_name) {
350 		clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
351 		if (!clnt->cl_principal)
352 			goto out_no_principal;
353 	}
354 
355 	atomic_set(&clnt->cl_count, 1);
356 
357 	err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
358 	if (err < 0)
359 		goto out_no_path;
360 
361 	auth = rpcauth_create(args->authflavor, clnt);
362 	if (IS_ERR(auth)) {
363 		printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
364 				args->authflavor);
365 		err = PTR_ERR(auth);
366 		goto out_no_auth;
367 	}
368 
369 	/* save the nodename */
370 	rpc_clnt_set_nodename(clnt, utsname()->nodename);
371 	rpc_register_client(clnt);
372 	return clnt;
373 
374 out_no_auth:
375 	rpc_clnt_remove_pipedir(clnt);
376 out_no_path:
377 	kfree(clnt->cl_principal);
378 out_no_principal:
379 	rpc_free_iostats(clnt->cl_metrics);
380 out_no_stats:
381 	kfree(clnt);
382 out_err:
383 	rpciod_down();
384 out_no_rpciod:
385 	xprt_put(xprt);
386 	return ERR_PTR(err);
387 }
388 
389 /**
390  * rpc_create - create an RPC client and transport with one call
391  * @args: rpc_clnt create argument structure
392  *
393  * Creates and initializes an RPC transport and an RPC client.
394  *
395  * It can ping the server in order to determine if it is up, and to see if
396  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
397  * this behavior so asynchronous tasks can also use rpc_create.
398  */
399 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
400 {
401 	struct rpc_xprt *xprt;
402 	struct rpc_clnt *clnt;
403 	struct xprt_create xprtargs = {
404 		.net = args->net,
405 		.ident = args->protocol,
406 		.srcaddr = args->saddress,
407 		.dstaddr = args->address,
408 		.addrlen = args->addrsize,
409 		.servername = args->servername,
410 		.bc_xprt = args->bc_xprt,
411 	};
412 	char servername[48];
413 
414 	/*
415 	 * If the caller chooses not to specify a hostname, whip
416 	 * up a string representation of the passed-in address.
417 	 */
418 	if (xprtargs.servername == NULL) {
419 		struct sockaddr_un *sun =
420 				(struct sockaddr_un *)args->address;
421 		struct sockaddr_in *sin =
422 				(struct sockaddr_in *)args->address;
423 		struct sockaddr_in6 *sin6 =
424 				(struct sockaddr_in6 *)args->address;
425 
426 		servername[0] = '\0';
427 		switch (args->address->sa_family) {
428 		case AF_LOCAL:
429 			snprintf(servername, sizeof(servername), "%s",
430 				 sun->sun_path);
431 			break;
432 		case AF_INET:
433 			snprintf(servername, sizeof(servername), "%pI4",
434 				 &sin->sin_addr.s_addr);
435 			break;
436 		case AF_INET6:
437 			snprintf(servername, sizeof(servername), "%pI6",
438 				 &sin6->sin6_addr);
439 			break;
440 		default:
441 			/* caller wants default server name, but
442 			 * address family isn't recognized. */
443 			return ERR_PTR(-EINVAL);
444 		}
445 		xprtargs.servername = servername;
446 	}
447 
448 	xprt = xprt_create_transport(&xprtargs);
449 	if (IS_ERR(xprt))
450 		return (struct rpc_clnt *)xprt;
451 
452 	/*
453 	 * By default, kernel RPC client connects from a reserved port.
454 	 * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
455 	 * but it is always enabled for rpciod, which handles the connect
456 	 * operation.
457 	 */
458 	xprt->resvport = 1;
459 	if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
460 		xprt->resvport = 0;
461 
462 	clnt = rpc_new_client(args, xprt);
463 	if (IS_ERR(clnt))
464 		return clnt;
465 
466 	if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
467 		int err = rpc_ping(clnt);
468 		if (err != 0) {
469 			rpc_shutdown_client(clnt);
470 			return ERR_PTR(err);
471 		}
472 	}
473 
474 	clnt->cl_softrtry = 1;
475 	if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
476 		clnt->cl_softrtry = 0;
477 
478 	if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
479 		clnt->cl_autobind = 1;
480 	if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
481 		clnt->cl_discrtry = 1;
482 	if (!(args->flags & RPC_CLNT_CREATE_QUIET))
483 		clnt->cl_chatty = 1;
484 
485 	return clnt;
486 }
487 EXPORT_SYMBOL_GPL(rpc_create);
488 
489 /*
490  * This function clones the RPC client structure. It allows us to share the
491  * same transport while varying parameters such as the authentication
492  * flavour.
493  */
494 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
495 					   struct rpc_clnt *clnt)
496 {
497 	struct rpc_xprt *xprt;
498 	struct rpc_clnt *new;
499 	int err;
500 
501 	err = -ENOMEM;
502 	rcu_read_lock();
503 	xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
504 	rcu_read_unlock();
505 	if (xprt == NULL)
506 		goto out_err;
507 	args->servername = xprt->servername;
508 
509 	new = rpc_new_client(args, xprt);
510 	if (IS_ERR(new)) {
511 		err = PTR_ERR(new);
512 		goto out_err;
513 	}
514 
515 	atomic_inc(&clnt->cl_count);
516 	new->cl_parent = clnt;
517 
518 	/* Turn off autobind on clones */
519 	new->cl_autobind = 0;
520 	new->cl_softrtry = clnt->cl_softrtry;
521 	new->cl_discrtry = clnt->cl_discrtry;
522 	new->cl_chatty = clnt->cl_chatty;
523 	return new;
524 
525 out_err:
526 	dprintk("RPC:       %s: returned error %d\n", __func__, err);
527 	return ERR_PTR(err);
528 }
529 
530 /**
531  * rpc_clone_client - Clone an RPC client structure
532  *
533  * @clnt: RPC client whose parameters are copied
534  *
535  * Returns a fresh RPC client or an ERR_PTR.
536  */
537 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
538 {
539 	struct rpc_create_args args = {
540 		.program	= clnt->cl_program,
541 		.prognumber	= clnt->cl_prog,
542 		.version	= clnt->cl_vers,
543 		.authflavor	= clnt->cl_auth->au_flavor,
544 		.client_name	= clnt->cl_principal,
545 	};
546 	return __rpc_clone_client(&args, clnt);
547 }
548 EXPORT_SYMBOL_GPL(rpc_clone_client);
549 
550 /**
551  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
552  *
553  * @clnt: RPC client whose parameters are copied
554  * @flavor: security flavor for new client
555  *
556  * Returns a fresh RPC client or an ERR_PTR.
557  */
558 struct rpc_clnt *
559 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
560 {
561 	struct rpc_create_args args = {
562 		.program	= clnt->cl_program,
563 		.prognumber	= clnt->cl_prog,
564 		.version	= clnt->cl_vers,
565 		.authflavor	= flavor,
566 		.client_name	= clnt->cl_principal,
567 	};
568 	return __rpc_clone_client(&args, clnt);
569 }
570 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
571 
572 /*
573  * Kill all tasks for the given client.
574  * XXX: kill their descendants as well?
575  */
576 void rpc_killall_tasks(struct rpc_clnt *clnt)
577 {
578 	struct rpc_task	*rovr;
579 
580 
581 	if (list_empty(&clnt->cl_tasks))
582 		return;
583 	dprintk("RPC:       killing all tasks for client %p\n", clnt);
584 	/*
585 	 * Spin lock all_tasks to prevent changes...
586 	 */
587 	spin_lock(&clnt->cl_lock);
588 	list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
589 		if (!RPC_IS_ACTIVATED(rovr))
590 			continue;
591 		if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
592 			rovr->tk_flags |= RPC_TASK_KILLED;
593 			rpc_exit(rovr, -EIO);
594 			if (RPC_IS_QUEUED(rovr))
595 				rpc_wake_up_queued_task(rovr->tk_waitqueue,
596 							rovr);
597 		}
598 	}
599 	spin_unlock(&clnt->cl_lock);
600 }
601 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
602 
603 /*
604  * Properly shut down an RPC client, terminating all outstanding
605  * requests.
606  */
607 void rpc_shutdown_client(struct rpc_clnt *clnt)
608 {
609 	might_sleep();
610 
611 	dprintk_rcu("RPC:       shutting down %s client for %s\n",
612 			clnt->cl_protname,
613 			rcu_dereference(clnt->cl_xprt)->servername);
614 
615 	while (!list_empty(&clnt->cl_tasks)) {
616 		rpc_killall_tasks(clnt);
617 		wait_event_timeout(destroy_wait,
618 			list_empty(&clnt->cl_tasks), 1*HZ);
619 	}
620 
621 	rpc_release_client(clnt);
622 }
623 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
624 
625 /*
626  * Free an RPC client
627  */
628 static void
629 rpc_free_client(struct rpc_clnt *clnt)
630 {
631 	dprintk_rcu("RPC:       destroying %s client for %s\n",
632 			clnt->cl_protname,
633 			rcu_dereference(clnt->cl_xprt)->servername);
634 	if (clnt->cl_parent != clnt)
635 		rpc_release_client(clnt->cl_parent);
636 	rpc_unregister_client(clnt);
637 	rpc_clnt_remove_pipedir(clnt);
638 	rpc_free_iostats(clnt->cl_metrics);
639 	kfree(clnt->cl_principal);
640 	clnt->cl_metrics = NULL;
641 	xprt_put(rcu_dereference_raw(clnt->cl_xprt));
642 	rpciod_down();
643 	kfree(clnt);
644 }
645 
646 /*
647  * Free an RPC client
648  */
649 static void
650 rpc_free_auth(struct rpc_clnt *clnt)
651 {
652 	if (clnt->cl_auth == NULL) {
653 		rpc_free_client(clnt);
654 		return;
655 	}
656 
657 	/*
658 	 * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
659 	 *       release remaining GSS contexts. This mechanism ensures
660 	 *       that it can do so safely.
661 	 */
662 	atomic_inc(&clnt->cl_count);
663 	rpcauth_release(clnt->cl_auth);
664 	clnt->cl_auth = NULL;
665 	if (atomic_dec_and_test(&clnt->cl_count))
666 		rpc_free_client(clnt);
667 }
668 
669 /*
670  * Release reference to the RPC client
671  */
672 void
673 rpc_release_client(struct rpc_clnt *clnt)
674 {
675 	dprintk("RPC:       rpc_release_client(%p)\n", clnt);
676 
677 	if (list_empty(&clnt->cl_tasks))
678 		wake_up(&destroy_wait);
679 	if (atomic_dec_and_test(&clnt->cl_count))
680 		rpc_free_auth(clnt);
681 }
682 
683 /**
684  * rpc_bind_new_program - bind a new RPC program to an existing client
685  * @old: old rpc_client
686  * @program: rpc program to set
687  * @vers: rpc program version
688  *
689  * Clones the rpc client and sets up a new RPC program. This is mainly
690  * of use for enabling different RPC programs to share the same transport.
691  * The Sun NFSv2/v3 ACL protocol can do this.
692  */
693 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
694 				      const struct rpc_program *program,
695 				      u32 vers)
696 {
697 	struct rpc_create_args args = {
698 		.program	= program,
699 		.prognumber	= program->number,
700 		.version	= vers,
701 		.authflavor	= old->cl_auth->au_flavor,
702 		.client_name	= old->cl_principal,
703 	};
704 	struct rpc_clnt *clnt;
705 	int err;
706 
707 	clnt = __rpc_clone_client(&args, old);
708 	if (IS_ERR(clnt))
709 		goto out;
710 	err = rpc_ping(clnt);
711 	if (err != 0) {
712 		rpc_shutdown_client(clnt);
713 		clnt = ERR_PTR(err);
714 	}
715 out:
716 	return clnt;
717 }
718 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
719 
720 void rpc_task_release_client(struct rpc_task *task)
721 {
722 	struct rpc_clnt *clnt = task->tk_client;
723 
724 	if (clnt != NULL) {
725 		/* Remove from client task list */
726 		spin_lock(&clnt->cl_lock);
727 		list_del(&task->tk_task);
728 		spin_unlock(&clnt->cl_lock);
729 		task->tk_client = NULL;
730 
731 		rpc_release_client(clnt);
732 	}
733 }
734 
735 static
736 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
737 {
738 	if (clnt != NULL) {
739 		rpc_task_release_client(task);
740 		task->tk_client = clnt;
741 		atomic_inc(&clnt->cl_count);
742 		if (clnt->cl_softrtry)
743 			task->tk_flags |= RPC_TASK_SOFT;
744 		if (sk_memalloc_socks()) {
745 			struct rpc_xprt *xprt;
746 
747 			rcu_read_lock();
748 			xprt = rcu_dereference(clnt->cl_xprt);
749 			if (xprt->swapper)
750 				task->tk_flags |= RPC_TASK_SWAPPER;
751 			rcu_read_unlock();
752 		}
753 		/* Add to the client's list of all tasks */
754 		spin_lock(&clnt->cl_lock);
755 		list_add_tail(&task->tk_task, &clnt->cl_tasks);
756 		spin_unlock(&clnt->cl_lock);
757 	}
758 }
759 
760 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
761 {
762 	rpc_task_release_client(task);
763 	rpc_task_set_client(task, clnt);
764 }
765 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
766 
767 
768 static void
769 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
770 {
771 	if (msg != NULL) {
772 		task->tk_msg.rpc_proc = msg->rpc_proc;
773 		task->tk_msg.rpc_argp = msg->rpc_argp;
774 		task->tk_msg.rpc_resp = msg->rpc_resp;
775 		if (msg->rpc_cred != NULL)
776 			task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
777 	}
778 }
779 
780 /*
781  * Default callback for async RPC calls
782  */
783 static void
784 rpc_default_callback(struct rpc_task *task, void *data)
785 {
786 }
787 
788 static const struct rpc_call_ops rpc_default_ops = {
789 	.rpc_call_done = rpc_default_callback,
790 };
791 
792 /**
793  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
794  * @task_setup_data: pointer to task initialisation data
795  */
796 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
797 {
798 	struct rpc_task *task;
799 
800 	task = rpc_new_task(task_setup_data);
801 	if (IS_ERR(task))
802 		goto out;
803 
804 	rpc_task_set_client(task, task_setup_data->rpc_client);
805 	rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
806 
807 	if (task->tk_action == NULL)
808 		rpc_call_start(task);
809 
810 	atomic_inc(&task->tk_count);
811 	rpc_execute(task);
812 out:
813 	return task;
814 }
815 EXPORT_SYMBOL_GPL(rpc_run_task);
816 
817 /**
818  * rpc_call_sync - Perform a synchronous RPC call
819  * @clnt: pointer to RPC client
820  * @msg: RPC call parameters
821  * @flags: RPC call flags
822  */
823 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
824 {
825 	struct rpc_task	*task;
826 	struct rpc_task_setup task_setup_data = {
827 		.rpc_client = clnt,
828 		.rpc_message = msg,
829 		.callback_ops = &rpc_default_ops,
830 		.flags = flags,
831 	};
832 	int status;
833 
834 	WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
835 	if (flags & RPC_TASK_ASYNC) {
836 		rpc_release_calldata(task_setup_data.callback_ops,
837 			task_setup_data.callback_data);
838 		return -EINVAL;
839 	}
840 
841 	task = rpc_run_task(&task_setup_data);
842 	if (IS_ERR(task))
843 		return PTR_ERR(task);
844 	status = task->tk_status;
845 	rpc_put_task(task);
846 	return status;
847 }
848 EXPORT_SYMBOL_GPL(rpc_call_sync);
849 
850 /**
851  * rpc_call_async - Perform an asynchronous RPC call
852  * @clnt: pointer to RPC client
853  * @msg: RPC call parameters
854  * @flags: RPC call flags
855  * @tk_ops: RPC call ops
856  * @data: user call data
857  */
858 int
859 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
860 	       const struct rpc_call_ops *tk_ops, void *data)
861 {
862 	struct rpc_task	*task;
863 	struct rpc_task_setup task_setup_data = {
864 		.rpc_client = clnt,
865 		.rpc_message = msg,
866 		.callback_ops = tk_ops,
867 		.callback_data = data,
868 		.flags = flags|RPC_TASK_ASYNC,
869 	};
870 
871 	task = rpc_run_task(&task_setup_data);
872 	if (IS_ERR(task))
873 		return PTR_ERR(task);
874 	rpc_put_task(task);
875 	return 0;
876 }
877 EXPORT_SYMBOL_GPL(rpc_call_async);
878 
879 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
880 /**
881  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
882  * rpc_execute against it
883  * @req: RPC request
884  * @tk_ops: RPC call ops
885  */
886 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
887 				const struct rpc_call_ops *tk_ops)
888 {
889 	struct rpc_task *task;
890 	struct xdr_buf *xbufp = &req->rq_snd_buf;
891 	struct rpc_task_setup task_setup_data = {
892 		.callback_ops = tk_ops,
893 	};
894 
895 	dprintk("RPC: rpc_run_bc_task req= %p\n", req);
896 	/*
897 	 * Create an rpc_task to send the data
898 	 */
899 	task = rpc_new_task(&task_setup_data);
900 	if (IS_ERR(task)) {
901 		xprt_free_bc_request(req);
902 		goto out;
903 	}
904 	task->tk_rqstp = req;
905 
906 	/*
907 	 * Set up the xdr_buf length.
908 	 * This also indicates that the buffer is XDR encoded already.
909 	 */
910 	xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
911 			xbufp->tail[0].iov_len;
912 
913 	task->tk_action = call_bc_transmit;
914 	atomic_inc(&task->tk_count);
915 	WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
916 	rpc_execute(task);
917 
918 out:
919 	dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
920 	return task;
921 }
922 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
923 
924 void
925 rpc_call_start(struct rpc_task *task)
926 {
927 	task->tk_action = call_start;
928 }
929 EXPORT_SYMBOL_GPL(rpc_call_start);
930 
931 /**
932  * rpc_peeraddr - extract remote peer address from clnt's xprt
933  * @clnt: RPC client structure
934  * @buf: target buffer
935  * @bufsize: length of target buffer
936  *
937  * Returns the number of bytes that are actually in the stored address.
938  */
939 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
940 {
941 	size_t bytes;
942 	struct rpc_xprt *xprt;
943 
944 	rcu_read_lock();
945 	xprt = rcu_dereference(clnt->cl_xprt);
946 
947 	bytes = xprt->addrlen;
948 	if (bytes > bufsize)
949 		bytes = bufsize;
950 	memcpy(buf, &xprt->addr, bytes);
951 	rcu_read_unlock();
952 
953 	return bytes;
954 }
955 EXPORT_SYMBOL_GPL(rpc_peeraddr);
956 
957 /**
958  * rpc_peeraddr2str - return remote peer address in printable format
959  * @clnt: RPC client structure
960  * @format: address format
961  *
962  * NB: the lifetime of the memory referenced by the returned pointer is
963  * the same as the rpc_xprt itself.  As long as the caller uses this
964  * pointer, it must hold the RCU read lock.
965  */
966 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
967 			     enum rpc_display_format_t format)
968 {
969 	struct rpc_xprt *xprt;
970 
971 	xprt = rcu_dereference(clnt->cl_xprt);
972 
973 	if (xprt->address_strings[format] != NULL)
974 		return xprt->address_strings[format];
975 	else
976 		return "unprintable";
977 }
978 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
979 
980 static const struct sockaddr_in rpc_inaddr_loopback = {
981 	.sin_family		= AF_INET,
982 	.sin_addr.s_addr	= htonl(INADDR_ANY),
983 };
984 
985 static const struct sockaddr_in6 rpc_in6addr_loopback = {
986 	.sin6_family		= AF_INET6,
987 	.sin6_addr		= IN6ADDR_ANY_INIT,
988 };
989 
990 /*
991  * Try a getsockname() on a connected datagram socket.  Using a
992  * connected datagram socket prevents leaving a socket in TIME_WAIT.
993  * This conserves the ephemeral port number space.
994  *
995  * Returns zero and fills in "buf" if successful; otherwise, a
996  * negative errno is returned.
997  */
998 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
999 			struct sockaddr *buf, int buflen)
1000 {
1001 	struct socket *sock;
1002 	int err;
1003 
1004 	err = __sock_create(net, sap->sa_family,
1005 				SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1006 	if (err < 0) {
1007 		dprintk("RPC:       can't create UDP socket (%d)\n", err);
1008 		goto out;
1009 	}
1010 
1011 	switch (sap->sa_family) {
1012 	case AF_INET:
1013 		err = kernel_bind(sock,
1014 				(struct sockaddr *)&rpc_inaddr_loopback,
1015 				sizeof(rpc_inaddr_loopback));
1016 		break;
1017 	case AF_INET6:
1018 		err = kernel_bind(sock,
1019 				(struct sockaddr *)&rpc_in6addr_loopback,
1020 				sizeof(rpc_in6addr_loopback));
1021 		break;
1022 	default:
1023 		err = -EAFNOSUPPORT;
1024 		goto out;
1025 	}
1026 	if (err < 0) {
1027 		dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1028 		goto out_release;
1029 	}
1030 
1031 	err = kernel_connect(sock, sap, salen, 0);
1032 	if (err < 0) {
1033 		dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1034 		goto out_release;
1035 	}
1036 
1037 	err = kernel_getsockname(sock, buf, &buflen);
1038 	if (err < 0) {
1039 		dprintk("RPC:       getsockname failed (%d)\n", err);
1040 		goto out_release;
1041 	}
1042 
1043 	err = 0;
1044 	if (buf->sa_family == AF_INET6) {
1045 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1046 		sin6->sin6_scope_id = 0;
1047 	}
1048 	dprintk("RPC:       %s succeeded\n", __func__);
1049 
1050 out_release:
1051 	sock_release(sock);
1052 out:
1053 	return err;
1054 }
1055 
1056 /*
1057  * Scraping a connected socket failed, so we don't have a useable
1058  * local address.  Fallback: generate an address that will prevent
1059  * the server from calling us back.
1060  *
1061  * Returns zero and fills in "buf" if successful; otherwise, a
1062  * negative errno is returned.
1063  */
1064 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1065 {
1066 	switch (family) {
1067 	case AF_INET:
1068 		if (buflen < sizeof(rpc_inaddr_loopback))
1069 			return -EINVAL;
1070 		memcpy(buf, &rpc_inaddr_loopback,
1071 				sizeof(rpc_inaddr_loopback));
1072 		break;
1073 	case AF_INET6:
1074 		if (buflen < sizeof(rpc_in6addr_loopback))
1075 			return -EINVAL;
1076 		memcpy(buf, &rpc_in6addr_loopback,
1077 				sizeof(rpc_in6addr_loopback));
1078 	default:
1079 		dprintk("RPC:       %s: address family not supported\n",
1080 			__func__);
1081 		return -EAFNOSUPPORT;
1082 	}
1083 	dprintk("RPC:       %s: succeeded\n", __func__);
1084 	return 0;
1085 }
1086 
1087 /**
1088  * rpc_localaddr - discover local endpoint address for an RPC client
1089  * @clnt: RPC client structure
1090  * @buf: target buffer
1091  * @buflen: size of target buffer, in bytes
1092  *
1093  * Returns zero and fills in "buf" and "buflen" if successful;
1094  * otherwise, a negative errno is returned.
1095  *
1096  * This works even if the underlying transport is not currently connected,
1097  * or if the upper layer never previously provided a source address.
1098  *
1099  * The result of this function call is transient: multiple calls in
1100  * succession may give different results, depending on how local
1101  * networking configuration changes over time.
1102  */
1103 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1104 {
1105 	struct sockaddr_storage address;
1106 	struct sockaddr *sap = (struct sockaddr *)&address;
1107 	struct rpc_xprt *xprt;
1108 	struct net *net;
1109 	size_t salen;
1110 	int err;
1111 
1112 	rcu_read_lock();
1113 	xprt = rcu_dereference(clnt->cl_xprt);
1114 	salen = xprt->addrlen;
1115 	memcpy(sap, &xprt->addr, salen);
1116 	net = get_net(xprt->xprt_net);
1117 	rcu_read_unlock();
1118 
1119 	rpc_set_port(sap, 0);
1120 	err = rpc_sockname(net, sap, salen, buf, buflen);
1121 	put_net(net);
1122 	if (err != 0)
1123 		/* Couldn't discover local address, return ANYADDR */
1124 		return rpc_anyaddr(sap->sa_family, buf, buflen);
1125 	return 0;
1126 }
1127 EXPORT_SYMBOL_GPL(rpc_localaddr);
1128 
1129 void
1130 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1131 {
1132 	struct rpc_xprt *xprt;
1133 
1134 	rcu_read_lock();
1135 	xprt = rcu_dereference(clnt->cl_xprt);
1136 	if (xprt->ops->set_buffer_size)
1137 		xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1138 	rcu_read_unlock();
1139 }
1140 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1141 
1142 /**
1143  * rpc_protocol - Get transport protocol number for an RPC client
1144  * @clnt: RPC client to query
1145  *
1146  */
1147 int rpc_protocol(struct rpc_clnt *clnt)
1148 {
1149 	int protocol;
1150 
1151 	rcu_read_lock();
1152 	protocol = rcu_dereference(clnt->cl_xprt)->prot;
1153 	rcu_read_unlock();
1154 	return protocol;
1155 }
1156 EXPORT_SYMBOL_GPL(rpc_protocol);
1157 
1158 /**
1159  * rpc_net_ns - Get the network namespace for this RPC client
1160  * @clnt: RPC client to query
1161  *
1162  */
1163 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1164 {
1165 	struct net *ret;
1166 
1167 	rcu_read_lock();
1168 	ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1169 	rcu_read_unlock();
1170 	return ret;
1171 }
1172 EXPORT_SYMBOL_GPL(rpc_net_ns);
1173 
1174 /**
1175  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1176  * @clnt: RPC client to query
1177  *
1178  * For stream transports, this is one RPC record fragment (see RFC
1179  * 1831), as we don't support multi-record requests yet.  For datagram
1180  * transports, this is the size of an IP packet minus the IP, UDP, and
1181  * RPC header sizes.
1182  */
1183 size_t rpc_max_payload(struct rpc_clnt *clnt)
1184 {
1185 	size_t ret;
1186 
1187 	rcu_read_lock();
1188 	ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1189 	rcu_read_unlock();
1190 	return ret;
1191 }
1192 EXPORT_SYMBOL_GPL(rpc_max_payload);
1193 
1194 /**
1195  * rpc_get_timeout - Get timeout for transport in units of HZ
1196  * @clnt: RPC client to query
1197  */
1198 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1199 {
1200 	unsigned long ret;
1201 
1202 	rcu_read_lock();
1203 	ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1204 	rcu_read_unlock();
1205 	return ret;
1206 }
1207 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1208 
1209 /**
1210  * rpc_force_rebind - force transport to check that remote port is unchanged
1211  * @clnt: client to rebind
1212  *
1213  */
1214 void rpc_force_rebind(struct rpc_clnt *clnt)
1215 {
1216 	if (clnt->cl_autobind) {
1217 		rcu_read_lock();
1218 		xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1219 		rcu_read_unlock();
1220 	}
1221 }
1222 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1223 
1224 /*
1225  * Restart an (async) RPC call from the call_prepare state.
1226  * Usually called from within the exit handler.
1227  */
1228 int
1229 rpc_restart_call_prepare(struct rpc_task *task)
1230 {
1231 	if (RPC_ASSASSINATED(task))
1232 		return 0;
1233 	task->tk_action = call_start;
1234 	if (task->tk_ops->rpc_call_prepare != NULL)
1235 		task->tk_action = rpc_prepare_task;
1236 	return 1;
1237 }
1238 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1239 
1240 /*
1241  * Restart an (async) RPC call. Usually called from within the
1242  * exit handler.
1243  */
1244 int
1245 rpc_restart_call(struct rpc_task *task)
1246 {
1247 	if (RPC_ASSASSINATED(task))
1248 		return 0;
1249 	task->tk_action = call_start;
1250 	return 1;
1251 }
1252 EXPORT_SYMBOL_GPL(rpc_restart_call);
1253 
1254 #ifdef RPC_DEBUG
1255 static const char *rpc_proc_name(const struct rpc_task *task)
1256 {
1257 	const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1258 
1259 	if (proc) {
1260 		if (proc->p_name)
1261 			return proc->p_name;
1262 		else
1263 			return "NULL";
1264 	} else
1265 		return "no proc";
1266 }
1267 #endif
1268 
1269 /*
1270  * 0.  Initial state
1271  *
1272  *     Other FSM states can be visited zero or more times, but
1273  *     this state is visited exactly once for each RPC.
1274  */
1275 static void
1276 call_start(struct rpc_task *task)
1277 {
1278 	struct rpc_clnt	*clnt = task->tk_client;
1279 
1280 	dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1281 			clnt->cl_protname, clnt->cl_vers,
1282 			rpc_proc_name(task),
1283 			(RPC_IS_ASYNC(task) ? "async" : "sync"));
1284 
1285 	/* Increment call count */
1286 	task->tk_msg.rpc_proc->p_count++;
1287 	clnt->cl_stats->rpccnt++;
1288 	task->tk_action = call_reserve;
1289 }
1290 
1291 /*
1292  * 1.	Reserve an RPC call slot
1293  */
1294 static void
1295 call_reserve(struct rpc_task *task)
1296 {
1297 	dprint_status(task);
1298 
1299 	task->tk_status  = 0;
1300 	task->tk_action  = call_reserveresult;
1301 	xprt_reserve(task);
1302 }
1303 
1304 /*
1305  * 1b.	Grok the result of xprt_reserve()
1306  */
1307 static void
1308 call_reserveresult(struct rpc_task *task)
1309 {
1310 	int status = task->tk_status;
1311 
1312 	dprint_status(task);
1313 
1314 	/*
1315 	 * After a call to xprt_reserve(), we must have either
1316 	 * a request slot or else an error status.
1317 	 */
1318 	task->tk_status = 0;
1319 	if (status >= 0) {
1320 		if (task->tk_rqstp) {
1321 			task->tk_action = call_refresh;
1322 			return;
1323 		}
1324 
1325 		printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1326 				__func__, status);
1327 		rpc_exit(task, -EIO);
1328 		return;
1329 	}
1330 
1331 	/*
1332 	 * Even though there was an error, we may have acquired
1333 	 * a request slot somehow.  Make sure not to leak it.
1334 	 */
1335 	if (task->tk_rqstp) {
1336 		printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1337 				__func__, status);
1338 		xprt_release(task);
1339 	}
1340 
1341 	switch (status) {
1342 	case -ENOMEM:
1343 		rpc_delay(task, HZ >> 2);
1344 	case -EAGAIN:	/* woken up; retry */
1345 		task->tk_action = call_reserve;
1346 		return;
1347 	case -EIO:	/* probably a shutdown */
1348 		break;
1349 	default:
1350 		printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1351 				__func__, status);
1352 		break;
1353 	}
1354 	rpc_exit(task, status);
1355 }
1356 
1357 /*
1358  * 2.	Bind and/or refresh the credentials
1359  */
1360 static void
1361 call_refresh(struct rpc_task *task)
1362 {
1363 	dprint_status(task);
1364 
1365 	task->tk_action = call_refreshresult;
1366 	task->tk_status = 0;
1367 	task->tk_client->cl_stats->rpcauthrefresh++;
1368 	rpcauth_refreshcred(task);
1369 }
1370 
1371 /*
1372  * 2a.	Process the results of a credential refresh
1373  */
1374 static void
1375 call_refreshresult(struct rpc_task *task)
1376 {
1377 	int status = task->tk_status;
1378 
1379 	dprint_status(task);
1380 
1381 	task->tk_status = 0;
1382 	task->tk_action = call_refresh;
1383 	switch (status) {
1384 	case 0:
1385 		if (rpcauth_uptodatecred(task))
1386 			task->tk_action = call_allocate;
1387 		return;
1388 	case -ETIMEDOUT:
1389 		rpc_delay(task, 3*HZ);
1390 	case -EKEYEXPIRED:
1391 	case -EAGAIN:
1392 		status = -EACCES;
1393 		if (!task->tk_cred_retry)
1394 			break;
1395 		task->tk_cred_retry--;
1396 		dprintk("RPC: %5u %s: retry refresh creds\n",
1397 				task->tk_pid, __func__);
1398 		return;
1399 	}
1400 	dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1401 				task->tk_pid, __func__, status);
1402 	rpc_exit(task, status);
1403 }
1404 
1405 /*
1406  * 2b.	Allocate the buffer. For details, see sched.c:rpc_malloc.
1407  *	(Note: buffer memory is freed in xprt_release).
1408  */
1409 static void
1410 call_allocate(struct rpc_task *task)
1411 {
1412 	unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1413 	struct rpc_rqst *req = task->tk_rqstp;
1414 	struct rpc_xprt *xprt = req->rq_xprt;
1415 	struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1416 
1417 	dprint_status(task);
1418 
1419 	task->tk_status = 0;
1420 	task->tk_action = call_bind;
1421 
1422 	if (req->rq_buffer)
1423 		return;
1424 
1425 	if (proc->p_proc != 0) {
1426 		BUG_ON(proc->p_arglen == 0);
1427 		if (proc->p_decode != NULL)
1428 			BUG_ON(proc->p_replen == 0);
1429 	}
1430 
1431 	/*
1432 	 * Calculate the size (in quads) of the RPC call
1433 	 * and reply headers, and convert both values
1434 	 * to byte sizes.
1435 	 */
1436 	req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1437 	req->rq_callsize <<= 2;
1438 	req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1439 	req->rq_rcvsize <<= 2;
1440 
1441 	req->rq_buffer = xprt->ops->buf_alloc(task,
1442 					req->rq_callsize + req->rq_rcvsize);
1443 	if (req->rq_buffer != NULL)
1444 		return;
1445 
1446 	dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1447 
1448 	if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1449 		task->tk_action = call_allocate;
1450 		rpc_delay(task, HZ>>4);
1451 		return;
1452 	}
1453 
1454 	rpc_exit(task, -ERESTARTSYS);
1455 }
1456 
1457 static inline int
1458 rpc_task_need_encode(struct rpc_task *task)
1459 {
1460 	return task->tk_rqstp->rq_snd_buf.len == 0;
1461 }
1462 
1463 static inline void
1464 rpc_task_force_reencode(struct rpc_task *task)
1465 {
1466 	task->tk_rqstp->rq_snd_buf.len = 0;
1467 	task->tk_rqstp->rq_bytes_sent = 0;
1468 }
1469 
1470 static inline void
1471 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1472 {
1473 	buf->head[0].iov_base = start;
1474 	buf->head[0].iov_len = len;
1475 	buf->tail[0].iov_len = 0;
1476 	buf->page_len = 0;
1477 	buf->flags = 0;
1478 	buf->len = 0;
1479 	buf->buflen = len;
1480 }
1481 
1482 /*
1483  * 3.	Encode arguments of an RPC call
1484  */
1485 static void
1486 rpc_xdr_encode(struct rpc_task *task)
1487 {
1488 	struct rpc_rqst	*req = task->tk_rqstp;
1489 	kxdreproc_t	encode;
1490 	__be32		*p;
1491 
1492 	dprint_status(task);
1493 
1494 	rpc_xdr_buf_init(&req->rq_snd_buf,
1495 			 req->rq_buffer,
1496 			 req->rq_callsize);
1497 	rpc_xdr_buf_init(&req->rq_rcv_buf,
1498 			 (char *)req->rq_buffer + req->rq_callsize,
1499 			 req->rq_rcvsize);
1500 
1501 	p = rpc_encode_header(task);
1502 	if (p == NULL) {
1503 		printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1504 		rpc_exit(task, -EIO);
1505 		return;
1506 	}
1507 
1508 	encode = task->tk_msg.rpc_proc->p_encode;
1509 	if (encode == NULL)
1510 		return;
1511 
1512 	task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1513 			task->tk_msg.rpc_argp);
1514 }
1515 
1516 /*
1517  * 4.	Get the server port number if not yet set
1518  */
1519 static void
1520 call_bind(struct rpc_task *task)
1521 {
1522 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1523 
1524 	dprint_status(task);
1525 
1526 	task->tk_action = call_connect;
1527 	if (!xprt_bound(xprt)) {
1528 		task->tk_action = call_bind_status;
1529 		task->tk_timeout = xprt->bind_timeout;
1530 		xprt->ops->rpcbind(task);
1531 	}
1532 }
1533 
1534 /*
1535  * 4a.	Sort out bind result
1536  */
1537 static void
1538 call_bind_status(struct rpc_task *task)
1539 {
1540 	int status = -EIO;
1541 
1542 	if (task->tk_status >= 0) {
1543 		dprint_status(task);
1544 		task->tk_status = 0;
1545 		task->tk_action = call_connect;
1546 		return;
1547 	}
1548 
1549 	trace_rpc_bind_status(task);
1550 	switch (task->tk_status) {
1551 	case -ENOMEM:
1552 		dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1553 		rpc_delay(task, HZ >> 2);
1554 		goto retry_timeout;
1555 	case -EACCES:
1556 		dprintk("RPC: %5u remote rpcbind: RPC program/version "
1557 				"unavailable\n", task->tk_pid);
1558 		/* fail immediately if this is an RPC ping */
1559 		if (task->tk_msg.rpc_proc->p_proc == 0) {
1560 			status = -EOPNOTSUPP;
1561 			break;
1562 		}
1563 		if (task->tk_rebind_retry == 0)
1564 			break;
1565 		task->tk_rebind_retry--;
1566 		rpc_delay(task, 3*HZ);
1567 		goto retry_timeout;
1568 	case -ETIMEDOUT:
1569 		dprintk("RPC: %5u rpcbind request timed out\n",
1570 				task->tk_pid);
1571 		goto retry_timeout;
1572 	case -EPFNOSUPPORT:
1573 		/* server doesn't support any rpcbind version we know of */
1574 		dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1575 				task->tk_pid);
1576 		break;
1577 	case -EPROTONOSUPPORT:
1578 		dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1579 				task->tk_pid);
1580 		task->tk_status = 0;
1581 		task->tk_action = call_bind;
1582 		return;
1583 	case -ECONNREFUSED:		/* connection problems */
1584 	case -ECONNRESET:
1585 	case -ENOTCONN:
1586 	case -EHOSTDOWN:
1587 	case -EHOSTUNREACH:
1588 	case -ENETUNREACH:
1589 	case -EPIPE:
1590 		dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1591 				task->tk_pid, task->tk_status);
1592 		if (!RPC_IS_SOFTCONN(task)) {
1593 			rpc_delay(task, 5*HZ);
1594 			goto retry_timeout;
1595 		}
1596 		status = task->tk_status;
1597 		break;
1598 	default:
1599 		dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1600 				task->tk_pid, -task->tk_status);
1601 	}
1602 
1603 	rpc_exit(task, status);
1604 	return;
1605 
1606 retry_timeout:
1607 	task->tk_action = call_timeout;
1608 }
1609 
1610 /*
1611  * 4b.	Connect to the RPC server
1612  */
1613 static void
1614 call_connect(struct rpc_task *task)
1615 {
1616 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1617 
1618 	dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1619 			task->tk_pid, xprt,
1620 			(xprt_connected(xprt) ? "is" : "is not"));
1621 
1622 	task->tk_action = call_transmit;
1623 	if (!xprt_connected(xprt)) {
1624 		task->tk_action = call_connect_status;
1625 		if (task->tk_status < 0)
1626 			return;
1627 		xprt_connect(task);
1628 	}
1629 }
1630 
1631 /*
1632  * 4c.	Sort out connect result
1633  */
1634 static void
1635 call_connect_status(struct rpc_task *task)
1636 {
1637 	struct rpc_clnt *clnt = task->tk_client;
1638 	int status = task->tk_status;
1639 
1640 	dprint_status(task);
1641 
1642 	task->tk_status = 0;
1643 	if (status >= 0 || status == -EAGAIN) {
1644 		clnt->cl_stats->netreconn++;
1645 		task->tk_action = call_transmit;
1646 		return;
1647 	}
1648 
1649 	trace_rpc_connect_status(task, status);
1650 	switch (status) {
1651 		/* if soft mounted, test if we've timed out */
1652 	case -ETIMEDOUT:
1653 		task->tk_action = call_timeout;
1654 		break;
1655 	default:
1656 		rpc_exit(task, -EIO);
1657 	}
1658 }
1659 
1660 /*
1661  * 5.	Transmit the RPC request, and wait for reply
1662  */
1663 static void
1664 call_transmit(struct rpc_task *task)
1665 {
1666 	dprint_status(task);
1667 
1668 	task->tk_action = call_status;
1669 	if (task->tk_status < 0)
1670 		return;
1671 	task->tk_status = xprt_prepare_transmit(task);
1672 	if (task->tk_status != 0)
1673 		return;
1674 	task->tk_action = call_transmit_status;
1675 	/* Encode here so that rpcsec_gss can use correct sequence number. */
1676 	if (rpc_task_need_encode(task)) {
1677 		rpc_xdr_encode(task);
1678 		/* Did the encode result in an error condition? */
1679 		if (task->tk_status != 0) {
1680 			/* Was the error nonfatal? */
1681 			if (task->tk_status == -EAGAIN)
1682 				rpc_delay(task, HZ >> 4);
1683 			else
1684 				rpc_exit(task, task->tk_status);
1685 			return;
1686 		}
1687 	}
1688 	xprt_transmit(task);
1689 	if (task->tk_status < 0)
1690 		return;
1691 	/*
1692 	 * On success, ensure that we call xprt_end_transmit() before sleeping
1693 	 * in order to allow access to the socket to other RPC requests.
1694 	 */
1695 	call_transmit_status(task);
1696 	if (rpc_reply_expected(task))
1697 		return;
1698 	task->tk_action = rpc_exit_task;
1699 	rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1700 }
1701 
1702 /*
1703  * 5a.	Handle cleanup after a transmission
1704  */
1705 static void
1706 call_transmit_status(struct rpc_task *task)
1707 {
1708 	task->tk_action = call_status;
1709 
1710 	/*
1711 	 * Common case: success.  Force the compiler to put this
1712 	 * test first.
1713 	 */
1714 	if (task->tk_status == 0) {
1715 		xprt_end_transmit(task);
1716 		rpc_task_force_reencode(task);
1717 		return;
1718 	}
1719 
1720 	switch (task->tk_status) {
1721 	case -EAGAIN:
1722 		break;
1723 	default:
1724 		dprint_status(task);
1725 		xprt_end_transmit(task);
1726 		rpc_task_force_reencode(task);
1727 		break;
1728 		/*
1729 		 * Special cases: if we've been waiting on the
1730 		 * socket's write_space() callback, or if the
1731 		 * socket just returned a connection error,
1732 		 * then hold onto the transport lock.
1733 		 */
1734 	case -ECONNREFUSED:
1735 	case -EHOSTDOWN:
1736 	case -EHOSTUNREACH:
1737 	case -ENETUNREACH:
1738 		if (RPC_IS_SOFTCONN(task)) {
1739 			xprt_end_transmit(task);
1740 			rpc_exit(task, task->tk_status);
1741 			break;
1742 		}
1743 	case -ECONNRESET:
1744 	case -ENOTCONN:
1745 	case -EPIPE:
1746 		rpc_task_force_reencode(task);
1747 	}
1748 }
1749 
1750 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1751 /*
1752  * 5b.	Send the backchannel RPC reply.  On error, drop the reply.  In
1753  * addition, disconnect on connectivity errors.
1754  */
1755 static void
1756 call_bc_transmit(struct rpc_task *task)
1757 {
1758 	struct rpc_rqst *req = task->tk_rqstp;
1759 
1760 	task->tk_status = xprt_prepare_transmit(task);
1761 	if (task->tk_status == -EAGAIN) {
1762 		/*
1763 		 * Could not reserve the transport. Try again after the
1764 		 * transport is released.
1765 		 */
1766 		task->tk_status = 0;
1767 		task->tk_action = call_bc_transmit;
1768 		return;
1769 	}
1770 
1771 	task->tk_action = rpc_exit_task;
1772 	if (task->tk_status < 0) {
1773 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1774 			"error: %d\n", task->tk_status);
1775 		return;
1776 	}
1777 
1778 	xprt_transmit(task);
1779 	xprt_end_transmit(task);
1780 	dprint_status(task);
1781 	switch (task->tk_status) {
1782 	case 0:
1783 		/* Success */
1784 		break;
1785 	case -EHOSTDOWN:
1786 	case -EHOSTUNREACH:
1787 	case -ENETUNREACH:
1788 	case -ETIMEDOUT:
1789 		/*
1790 		 * Problem reaching the server.  Disconnect and let the
1791 		 * forechannel reestablish the connection.  The server will
1792 		 * have to retransmit the backchannel request and we'll
1793 		 * reprocess it.  Since these ops are idempotent, there's no
1794 		 * need to cache our reply at this time.
1795 		 */
1796 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1797 			"error: %d\n", task->tk_status);
1798 		xprt_conditional_disconnect(req->rq_xprt,
1799 			req->rq_connect_cookie);
1800 		break;
1801 	default:
1802 		/*
1803 		 * We were unable to reply and will have to drop the
1804 		 * request.  The server should reconnect and retransmit.
1805 		 */
1806 		WARN_ON_ONCE(task->tk_status == -EAGAIN);
1807 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1808 			"error: %d\n", task->tk_status);
1809 		break;
1810 	}
1811 	rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1812 }
1813 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1814 
1815 /*
1816  * 6.	Sort out the RPC call status
1817  */
1818 static void
1819 call_status(struct rpc_task *task)
1820 {
1821 	struct rpc_clnt	*clnt = task->tk_client;
1822 	struct rpc_rqst	*req = task->tk_rqstp;
1823 	int		status;
1824 
1825 	if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
1826 		task->tk_status = req->rq_reply_bytes_recvd;
1827 
1828 	dprint_status(task);
1829 
1830 	status = task->tk_status;
1831 	if (status >= 0) {
1832 		task->tk_action = call_decode;
1833 		return;
1834 	}
1835 
1836 	trace_rpc_call_status(task);
1837 	task->tk_status = 0;
1838 	switch(status) {
1839 	case -EHOSTDOWN:
1840 	case -EHOSTUNREACH:
1841 	case -ENETUNREACH:
1842 		/*
1843 		 * Delay any retries for 3 seconds, then handle as if it
1844 		 * were a timeout.
1845 		 */
1846 		rpc_delay(task, 3*HZ);
1847 	case -ETIMEDOUT:
1848 		task->tk_action = call_timeout;
1849 		if (task->tk_client->cl_discrtry)
1850 			xprt_conditional_disconnect(req->rq_xprt,
1851 					req->rq_connect_cookie);
1852 		break;
1853 	case -ECONNRESET:
1854 	case -ECONNREFUSED:
1855 		rpc_force_rebind(clnt);
1856 		rpc_delay(task, 3*HZ);
1857 	case -EPIPE:
1858 	case -ENOTCONN:
1859 		task->tk_action = call_bind;
1860 		break;
1861 	case -EAGAIN:
1862 		task->tk_action = call_transmit;
1863 		break;
1864 	case -EIO:
1865 		/* shutdown or soft timeout */
1866 		rpc_exit(task, status);
1867 		break;
1868 	default:
1869 		if (clnt->cl_chatty)
1870 			printk("%s: RPC call returned error %d\n",
1871 			       clnt->cl_protname, -status);
1872 		rpc_exit(task, status);
1873 	}
1874 }
1875 
1876 /*
1877  * 6a.	Handle RPC timeout
1878  * 	We do not release the request slot, so we keep using the
1879  *	same XID for all retransmits.
1880  */
1881 static void
1882 call_timeout(struct rpc_task *task)
1883 {
1884 	struct rpc_clnt	*clnt = task->tk_client;
1885 
1886 	if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1887 		dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1888 		goto retry;
1889 	}
1890 
1891 	dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1892 	task->tk_timeouts++;
1893 
1894 	if (RPC_IS_SOFTCONN(task)) {
1895 		rpc_exit(task, -ETIMEDOUT);
1896 		return;
1897 	}
1898 	if (RPC_IS_SOFT(task)) {
1899 		if (clnt->cl_chatty) {
1900 			rcu_read_lock();
1901 			printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1902 				clnt->cl_protname,
1903 				rcu_dereference(clnt->cl_xprt)->servername);
1904 			rcu_read_unlock();
1905 		}
1906 		if (task->tk_flags & RPC_TASK_TIMEOUT)
1907 			rpc_exit(task, -ETIMEDOUT);
1908 		else
1909 			rpc_exit(task, -EIO);
1910 		return;
1911 	}
1912 
1913 	if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1914 		task->tk_flags |= RPC_CALL_MAJORSEEN;
1915 		if (clnt->cl_chatty) {
1916 			rcu_read_lock();
1917 			printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1918 			clnt->cl_protname,
1919 			rcu_dereference(clnt->cl_xprt)->servername);
1920 			rcu_read_unlock();
1921 		}
1922 	}
1923 	rpc_force_rebind(clnt);
1924 	/*
1925 	 * Did our request time out due to an RPCSEC_GSS out-of-sequence
1926 	 * event? RFC2203 requires the server to drop all such requests.
1927 	 */
1928 	rpcauth_invalcred(task);
1929 
1930 retry:
1931 	clnt->cl_stats->rpcretrans++;
1932 	task->tk_action = call_bind;
1933 	task->tk_status = 0;
1934 }
1935 
1936 /*
1937  * 7.	Decode the RPC reply
1938  */
1939 static void
1940 call_decode(struct rpc_task *task)
1941 {
1942 	struct rpc_clnt	*clnt = task->tk_client;
1943 	struct rpc_rqst	*req = task->tk_rqstp;
1944 	kxdrdproc_t	decode = task->tk_msg.rpc_proc->p_decode;
1945 	__be32		*p;
1946 
1947 	dprint_status(task);
1948 
1949 	if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1950 		if (clnt->cl_chatty) {
1951 			rcu_read_lock();
1952 			printk(KERN_NOTICE "%s: server %s OK\n",
1953 				clnt->cl_protname,
1954 				rcu_dereference(clnt->cl_xprt)->servername);
1955 			rcu_read_unlock();
1956 		}
1957 		task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1958 	}
1959 
1960 	/*
1961 	 * Ensure that we see all writes made by xprt_complete_rqst()
1962 	 * before it changed req->rq_reply_bytes_recvd.
1963 	 */
1964 	smp_rmb();
1965 	req->rq_rcv_buf.len = req->rq_private_buf.len;
1966 
1967 	/* Check that the softirq receive buffer is valid */
1968 	WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1969 				sizeof(req->rq_rcv_buf)) != 0);
1970 
1971 	if (req->rq_rcv_buf.len < 12) {
1972 		if (!RPC_IS_SOFT(task)) {
1973 			task->tk_action = call_bind;
1974 			clnt->cl_stats->rpcretrans++;
1975 			goto out_retry;
1976 		}
1977 		dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
1978 				clnt->cl_protname, task->tk_status);
1979 		task->tk_action = call_timeout;
1980 		goto out_retry;
1981 	}
1982 
1983 	p = rpc_verify_header(task);
1984 	if (IS_ERR(p)) {
1985 		if (p == ERR_PTR(-EAGAIN))
1986 			goto out_retry;
1987 		return;
1988 	}
1989 
1990 	task->tk_action = rpc_exit_task;
1991 
1992 	if (decode) {
1993 		task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
1994 						      task->tk_msg.rpc_resp);
1995 	}
1996 	dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
1997 			task->tk_status);
1998 	return;
1999 out_retry:
2000 	task->tk_status = 0;
2001 	/* Note: rpc_verify_header() may have freed the RPC slot */
2002 	if (task->tk_rqstp == req) {
2003 		req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2004 		if (task->tk_client->cl_discrtry)
2005 			xprt_conditional_disconnect(req->rq_xprt,
2006 					req->rq_connect_cookie);
2007 	}
2008 }
2009 
2010 static __be32 *
2011 rpc_encode_header(struct rpc_task *task)
2012 {
2013 	struct rpc_clnt *clnt = task->tk_client;
2014 	struct rpc_rqst	*req = task->tk_rqstp;
2015 	__be32		*p = req->rq_svec[0].iov_base;
2016 
2017 	/* FIXME: check buffer size? */
2018 
2019 	p = xprt_skip_transport_header(req->rq_xprt, p);
2020 	*p++ = req->rq_xid;		/* XID */
2021 	*p++ = htonl(RPC_CALL);		/* CALL */
2022 	*p++ = htonl(RPC_VERSION);	/* RPC version */
2023 	*p++ = htonl(clnt->cl_prog);	/* program number */
2024 	*p++ = htonl(clnt->cl_vers);	/* program version */
2025 	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */
2026 	p = rpcauth_marshcred(task, p);
2027 	req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2028 	return p;
2029 }
2030 
2031 static __be32 *
2032 rpc_verify_header(struct rpc_task *task)
2033 {
2034 	struct rpc_clnt *clnt = task->tk_client;
2035 	struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2036 	int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2037 	__be32	*p = iov->iov_base;
2038 	u32 n;
2039 	int error = -EACCES;
2040 
2041 	if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2042 		/* RFC-1014 says that the representation of XDR data must be a
2043 		 * multiple of four bytes
2044 		 * - if it isn't pointer subtraction in the NFS client may give
2045 		 *   undefined results
2046 		 */
2047 		dprintk("RPC: %5u %s: XDR representation not a multiple of"
2048 		       " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2049 		       task->tk_rqstp->rq_rcv_buf.len);
2050 		goto out_eio;
2051 	}
2052 	if ((len -= 3) < 0)
2053 		goto out_overflow;
2054 
2055 	p += 1; /* skip XID */
2056 	if ((n = ntohl(*p++)) != RPC_REPLY) {
2057 		dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2058 			task->tk_pid, __func__, n);
2059 		goto out_garbage;
2060 	}
2061 
2062 	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2063 		if (--len < 0)
2064 			goto out_overflow;
2065 		switch ((n = ntohl(*p++))) {
2066 		case RPC_AUTH_ERROR:
2067 			break;
2068 		case RPC_MISMATCH:
2069 			dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2070 				task->tk_pid, __func__);
2071 			error = -EPROTONOSUPPORT;
2072 			goto out_err;
2073 		default:
2074 			dprintk("RPC: %5u %s: RPC call rejected, "
2075 				"unknown error: %x\n",
2076 				task->tk_pid, __func__, n);
2077 			goto out_eio;
2078 		}
2079 		if (--len < 0)
2080 			goto out_overflow;
2081 		switch ((n = ntohl(*p++))) {
2082 		case RPC_AUTH_REJECTEDCRED:
2083 		case RPC_AUTH_REJECTEDVERF:
2084 		case RPCSEC_GSS_CREDPROBLEM:
2085 		case RPCSEC_GSS_CTXPROBLEM:
2086 			if (!task->tk_cred_retry)
2087 				break;
2088 			task->tk_cred_retry--;
2089 			dprintk("RPC: %5u %s: retry stale creds\n",
2090 					task->tk_pid, __func__);
2091 			rpcauth_invalcred(task);
2092 			/* Ensure we obtain a new XID! */
2093 			xprt_release(task);
2094 			task->tk_action = call_reserve;
2095 			goto out_retry;
2096 		case RPC_AUTH_BADCRED:
2097 		case RPC_AUTH_BADVERF:
2098 			/* possibly garbled cred/verf? */
2099 			if (!task->tk_garb_retry)
2100 				break;
2101 			task->tk_garb_retry--;
2102 			dprintk("RPC: %5u %s: retry garbled creds\n",
2103 					task->tk_pid, __func__);
2104 			task->tk_action = call_bind;
2105 			goto out_retry;
2106 		case RPC_AUTH_TOOWEAK:
2107 			rcu_read_lock();
2108 			printk(KERN_NOTICE "RPC: server %s requires stronger "
2109 			       "authentication.\n",
2110 			       rcu_dereference(clnt->cl_xprt)->servername);
2111 			rcu_read_unlock();
2112 			break;
2113 		default:
2114 			dprintk("RPC: %5u %s: unknown auth error: %x\n",
2115 					task->tk_pid, __func__, n);
2116 			error = -EIO;
2117 		}
2118 		dprintk("RPC: %5u %s: call rejected %d\n",
2119 				task->tk_pid, __func__, n);
2120 		goto out_err;
2121 	}
2122 	if (!(p = rpcauth_checkverf(task, p))) {
2123 		dprintk("RPC: %5u %s: auth check failed\n",
2124 				task->tk_pid, __func__);
2125 		goto out_garbage;		/* bad verifier, retry */
2126 	}
2127 	len = p - (__be32 *)iov->iov_base - 1;
2128 	if (len < 0)
2129 		goto out_overflow;
2130 	switch ((n = ntohl(*p++))) {
2131 	case RPC_SUCCESS:
2132 		return p;
2133 	case RPC_PROG_UNAVAIL:
2134 		dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2135 				"by server %s\n", task->tk_pid, __func__,
2136 				(unsigned int)clnt->cl_prog,
2137 				rcu_dereference(clnt->cl_xprt)->servername);
2138 		error = -EPFNOSUPPORT;
2139 		goto out_err;
2140 	case RPC_PROG_MISMATCH:
2141 		dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2142 				"by server %s\n", task->tk_pid, __func__,
2143 				(unsigned int)clnt->cl_prog,
2144 				(unsigned int)clnt->cl_vers,
2145 				rcu_dereference(clnt->cl_xprt)->servername);
2146 		error = -EPROTONOSUPPORT;
2147 		goto out_err;
2148 	case RPC_PROC_UNAVAIL:
2149 		dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2150 				"version %u on server %s\n",
2151 				task->tk_pid, __func__,
2152 				rpc_proc_name(task),
2153 				clnt->cl_prog, clnt->cl_vers,
2154 				rcu_dereference(clnt->cl_xprt)->servername);
2155 		error = -EOPNOTSUPP;
2156 		goto out_err;
2157 	case RPC_GARBAGE_ARGS:
2158 		dprintk("RPC: %5u %s: server saw garbage\n",
2159 				task->tk_pid, __func__);
2160 		break;			/* retry */
2161 	default:
2162 		dprintk("RPC: %5u %s: server accept status: %x\n",
2163 				task->tk_pid, __func__, n);
2164 		/* Also retry */
2165 	}
2166 
2167 out_garbage:
2168 	clnt->cl_stats->rpcgarbage++;
2169 	if (task->tk_garb_retry) {
2170 		task->tk_garb_retry--;
2171 		dprintk("RPC: %5u %s: retrying\n",
2172 				task->tk_pid, __func__);
2173 		task->tk_action = call_bind;
2174 out_retry:
2175 		return ERR_PTR(-EAGAIN);
2176 	}
2177 out_eio:
2178 	error = -EIO;
2179 out_err:
2180 	rpc_exit(task, error);
2181 	dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2182 			__func__, error);
2183 	return ERR_PTR(error);
2184 out_overflow:
2185 	dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2186 			__func__);
2187 	goto out_garbage;
2188 }
2189 
2190 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2191 {
2192 }
2193 
2194 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2195 {
2196 	return 0;
2197 }
2198 
2199 static struct rpc_procinfo rpcproc_null = {
2200 	.p_encode = rpcproc_encode_null,
2201 	.p_decode = rpcproc_decode_null,
2202 };
2203 
2204 static int rpc_ping(struct rpc_clnt *clnt)
2205 {
2206 	struct rpc_message msg = {
2207 		.rpc_proc = &rpcproc_null,
2208 	};
2209 	int err;
2210 	msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2211 	err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2212 	put_rpccred(msg.rpc_cred);
2213 	return err;
2214 }
2215 
2216 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2217 {
2218 	struct rpc_message msg = {
2219 		.rpc_proc = &rpcproc_null,
2220 		.rpc_cred = cred,
2221 	};
2222 	struct rpc_task_setup task_setup_data = {
2223 		.rpc_client = clnt,
2224 		.rpc_message = &msg,
2225 		.callback_ops = &rpc_default_ops,
2226 		.flags = flags,
2227 	};
2228 	return rpc_run_task(&task_setup_data);
2229 }
2230 EXPORT_SYMBOL_GPL(rpc_call_null);
2231 
2232 #ifdef RPC_DEBUG
2233 static void rpc_show_header(void)
2234 {
2235 	printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2236 		"-timeout ---ops--\n");
2237 }
2238 
2239 static void rpc_show_task(const struct rpc_clnt *clnt,
2240 			  const struct rpc_task *task)
2241 {
2242 	const char *rpc_waitq = "none";
2243 
2244 	if (RPC_IS_QUEUED(task))
2245 		rpc_waitq = rpc_qname(task->tk_waitqueue);
2246 
2247 	printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2248 		task->tk_pid, task->tk_flags, task->tk_status,
2249 		clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2250 		clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
2251 		task->tk_action, rpc_waitq);
2252 }
2253 
2254 void rpc_show_tasks(struct net *net)
2255 {
2256 	struct rpc_clnt *clnt;
2257 	struct rpc_task *task;
2258 	int header = 0;
2259 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2260 
2261 	spin_lock(&sn->rpc_client_lock);
2262 	list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2263 		spin_lock(&clnt->cl_lock);
2264 		list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2265 			if (!header) {
2266 				rpc_show_header();
2267 				header++;
2268 			}
2269 			rpc_show_task(clnt, task);
2270 		}
2271 		spin_unlock(&clnt->cl_lock);
2272 	}
2273 	spin_unlock(&sn->rpc_client_lock);
2274 }
2275 #endif
2276