xref: /linux/net/sunrpc/clnt.c (revision 33d90ac0581ce81d1ebfc51918a2757e41a6011c)
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 	err = -EINVAL;
308 	if (!xprt)
309 		goto out_no_xprt;
310 
311 	if (args->version >= program->nrvers)
312 		goto out_err;
313 	version = program->version[args->version];
314 	if (version == NULL)
315 		goto out_err;
316 
317 	err = -ENOMEM;
318 	clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
319 	if (!clnt)
320 		goto out_err;
321 	clnt->cl_parent = clnt;
322 
323 	rcu_assign_pointer(clnt->cl_xprt, xprt);
324 	clnt->cl_procinfo = version->procs;
325 	clnt->cl_maxproc  = version->nrprocs;
326 	clnt->cl_protname = program->name;
327 	clnt->cl_prog     = args->prognumber ? : program->number;
328 	clnt->cl_vers     = version->number;
329 	clnt->cl_stats    = program->stats;
330 	clnt->cl_metrics  = rpc_alloc_iostats(clnt);
331 	err = -ENOMEM;
332 	if (clnt->cl_metrics == NULL)
333 		goto out_no_stats;
334 	clnt->cl_program  = program;
335 	INIT_LIST_HEAD(&clnt->cl_tasks);
336 	spin_lock_init(&clnt->cl_lock);
337 
338 	if (!xprt_bound(xprt))
339 		clnt->cl_autobind = 1;
340 
341 	clnt->cl_timeout = xprt->timeout;
342 	if (args->timeout != NULL) {
343 		memcpy(&clnt->cl_timeout_default, args->timeout,
344 				sizeof(clnt->cl_timeout_default));
345 		clnt->cl_timeout = &clnt->cl_timeout_default;
346 	}
347 
348 	clnt->cl_rtt = &clnt->cl_rtt_default;
349 	rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
350 	clnt->cl_principal = NULL;
351 	if (args->client_name) {
352 		clnt->cl_principal = kstrdup(args->client_name, GFP_KERNEL);
353 		if (!clnt->cl_principal)
354 			goto out_no_principal;
355 	}
356 
357 	atomic_set(&clnt->cl_count, 1);
358 
359 	err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
360 	if (err < 0)
361 		goto out_no_path;
362 
363 	auth = rpcauth_create(args->authflavor, clnt);
364 	if (IS_ERR(auth)) {
365 		printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
366 				args->authflavor);
367 		err = PTR_ERR(auth);
368 		goto out_no_auth;
369 	}
370 
371 	/* save the nodename */
372 	rpc_clnt_set_nodename(clnt, utsname()->nodename);
373 	rpc_register_client(clnt);
374 	return clnt;
375 
376 out_no_auth:
377 	rpc_clnt_remove_pipedir(clnt);
378 out_no_path:
379 	kfree(clnt->cl_principal);
380 out_no_principal:
381 	rpc_free_iostats(clnt->cl_metrics);
382 out_no_stats:
383 	kfree(clnt);
384 out_err:
385 	xprt_put(xprt);
386 out_no_xprt:
387 	rpciod_down();
388 out_no_rpciod:
389 	return ERR_PTR(err);
390 }
391 
392 /**
393  * rpc_create - create an RPC client and transport with one call
394  * @args: rpc_clnt create argument structure
395  *
396  * Creates and initializes an RPC transport and an RPC client.
397  *
398  * It can ping the server in order to determine if it is up, and to see if
399  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
400  * this behavior so asynchronous tasks can also use rpc_create.
401  */
402 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
403 {
404 	struct rpc_xprt *xprt;
405 	struct rpc_clnt *clnt;
406 	struct xprt_create xprtargs = {
407 		.net = args->net,
408 		.ident = args->protocol,
409 		.srcaddr = args->saddress,
410 		.dstaddr = args->address,
411 		.addrlen = args->addrsize,
412 		.servername = args->servername,
413 		.bc_xprt = args->bc_xprt,
414 	};
415 	char servername[48];
416 
417 	if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
418 		xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
419 	if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
420 		xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
421 	/*
422 	 * If the caller chooses not to specify a hostname, whip
423 	 * up a string representation of the passed-in address.
424 	 */
425 	if (xprtargs.servername == NULL) {
426 		struct sockaddr_un *sun =
427 				(struct sockaddr_un *)args->address;
428 		struct sockaddr_in *sin =
429 				(struct sockaddr_in *)args->address;
430 		struct sockaddr_in6 *sin6 =
431 				(struct sockaddr_in6 *)args->address;
432 
433 		servername[0] = '\0';
434 		switch (args->address->sa_family) {
435 		case AF_LOCAL:
436 			snprintf(servername, sizeof(servername), "%s",
437 				 sun->sun_path);
438 			break;
439 		case AF_INET:
440 			snprintf(servername, sizeof(servername), "%pI4",
441 				 &sin->sin_addr.s_addr);
442 			break;
443 		case AF_INET6:
444 			snprintf(servername, sizeof(servername), "%pI6",
445 				 &sin6->sin6_addr);
446 			break;
447 		default:
448 			/* caller wants default server name, but
449 			 * address family isn't recognized. */
450 			return ERR_PTR(-EINVAL);
451 		}
452 		xprtargs.servername = servername;
453 	}
454 
455 	xprt = xprt_create_transport(&xprtargs);
456 	if (IS_ERR(xprt))
457 		return (struct rpc_clnt *)xprt;
458 
459 	/*
460 	 * By default, kernel RPC client connects from a reserved port.
461 	 * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
462 	 * but it is always enabled for rpciod, which handles the connect
463 	 * operation.
464 	 */
465 	xprt->resvport = 1;
466 	if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
467 		xprt->resvport = 0;
468 
469 	clnt = rpc_new_client(args, xprt);
470 	if (IS_ERR(clnt))
471 		return clnt;
472 
473 	if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
474 		int err = rpc_ping(clnt);
475 		if (err != 0) {
476 			rpc_shutdown_client(clnt);
477 			return ERR_PTR(err);
478 		}
479 	}
480 
481 	clnt->cl_softrtry = 1;
482 	if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
483 		clnt->cl_softrtry = 0;
484 
485 	if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
486 		clnt->cl_autobind = 1;
487 	if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
488 		clnt->cl_discrtry = 1;
489 	if (!(args->flags & RPC_CLNT_CREATE_QUIET))
490 		clnt->cl_chatty = 1;
491 
492 	return clnt;
493 }
494 EXPORT_SYMBOL_GPL(rpc_create);
495 
496 /*
497  * This function clones the RPC client structure. It allows us to share the
498  * same transport while varying parameters such as the authentication
499  * flavour.
500  */
501 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
502 					   struct rpc_clnt *clnt)
503 {
504 	struct rpc_xprt *xprt;
505 	struct rpc_clnt *new;
506 	int err;
507 
508 	err = -ENOMEM;
509 	rcu_read_lock();
510 	xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
511 	rcu_read_unlock();
512 	if (xprt == NULL)
513 		goto out_err;
514 	args->servername = xprt->servername;
515 
516 	new = rpc_new_client(args, xprt);
517 	if (IS_ERR(new)) {
518 		err = PTR_ERR(new);
519 		goto out_put;
520 	}
521 
522 	atomic_inc(&clnt->cl_count);
523 	new->cl_parent = clnt;
524 
525 	/* Turn off autobind on clones */
526 	new->cl_autobind = 0;
527 	new->cl_softrtry = clnt->cl_softrtry;
528 	new->cl_discrtry = clnt->cl_discrtry;
529 	new->cl_chatty = clnt->cl_chatty;
530 	return new;
531 
532 out_put:
533 	xprt_put(xprt);
534 out_err:
535 	dprintk("RPC:       %s: returned error %d\n", __func__, err);
536 	return ERR_PTR(err);
537 }
538 
539 /**
540  * rpc_clone_client - Clone an RPC client structure
541  *
542  * @clnt: RPC client whose parameters are copied
543  *
544  * Returns a fresh RPC client or an ERR_PTR.
545  */
546 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
547 {
548 	struct rpc_create_args args = {
549 		.program	= clnt->cl_program,
550 		.prognumber	= clnt->cl_prog,
551 		.version	= clnt->cl_vers,
552 		.authflavor	= clnt->cl_auth->au_flavor,
553 		.client_name	= clnt->cl_principal,
554 	};
555 	return __rpc_clone_client(&args, clnt);
556 }
557 EXPORT_SYMBOL_GPL(rpc_clone_client);
558 
559 /**
560  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
561  *
562  * @clnt: RPC client whose parameters are copied
563  * @flavor: security flavor for new client
564  *
565  * Returns a fresh RPC client or an ERR_PTR.
566  */
567 struct rpc_clnt *
568 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
569 {
570 	struct rpc_create_args args = {
571 		.program	= clnt->cl_program,
572 		.prognumber	= clnt->cl_prog,
573 		.version	= clnt->cl_vers,
574 		.authflavor	= flavor,
575 		.client_name	= clnt->cl_principal,
576 	};
577 	return __rpc_clone_client(&args, clnt);
578 }
579 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
580 
581 /*
582  * Kill all tasks for the given client.
583  * XXX: kill their descendants as well?
584  */
585 void rpc_killall_tasks(struct rpc_clnt *clnt)
586 {
587 	struct rpc_task	*rovr;
588 
589 
590 	if (list_empty(&clnt->cl_tasks))
591 		return;
592 	dprintk("RPC:       killing all tasks for client %p\n", clnt);
593 	/*
594 	 * Spin lock all_tasks to prevent changes...
595 	 */
596 	spin_lock(&clnt->cl_lock);
597 	list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
598 		if (!RPC_IS_ACTIVATED(rovr))
599 			continue;
600 		if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
601 			rovr->tk_flags |= RPC_TASK_KILLED;
602 			rpc_exit(rovr, -EIO);
603 			if (RPC_IS_QUEUED(rovr))
604 				rpc_wake_up_queued_task(rovr->tk_waitqueue,
605 							rovr);
606 		}
607 	}
608 	spin_unlock(&clnt->cl_lock);
609 }
610 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
611 
612 /*
613  * Properly shut down an RPC client, terminating all outstanding
614  * requests.
615  */
616 void rpc_shutdown_client(struct rpc_clnt *clnt)
617 {
618 	might_sleep();
619 
620 	dprintk_rcu("RPC:       shutting down %s client for %s\n",
621 			clnt->cl_protname,
622 			rcu_dereference(clnt->cl_xprt)->servername);
623 
624 	while (!list_empty(&clnt->cl_tasks)) {
625 		rpc_killall_tasks(clnt);
626 		wait_event_timeout(destroy_wait,
627 			list_empty(&clnt->cl_tasks), 1*HZ);
628 	}
629 
630 	rpc_release_client(clnt);
631 }
632 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
633 
634 /*
635  * Free an RPC client
636  */
637 static void
638 rpc_free_client(struct rpc_clnt *clnt)
639 {
640 	dprintk_rcu("RPC:       destroying %s client for %s\n",
641 			clnt->cl_protname,
642 			rcu_dereference(clnt->cl_xprt)->servername);
643 	if (clnt->cl_parent != clnt)
644 		rpc_release_client(clnt->cl_parent);
645 	rpc_unregister_client(clnt);
646 	rpc_clnt_remove_pipedir(clnt);
647 	rpc_free_iostats(clnt->cl_metrics);
648 	kfree(clnt->cl_principal);
649 	clnt->cl_metrics = NULL;
650 	xprt_put(rcu_dereference_raw(clnt->cl_xprt));
651 	rpciod_down();
652 	kfree(clnt);
653 }
654 
655 /*
656  * Free an RPC client
657  */
658 static void
659 rpc_free_auth(struct rpc_clnt *clnt)
660 {
661 	if (clnt->cl_auth == NULL) {
662 		rpc_free_client(clnt);
663 		return;
664 	}
665 
666 	/*
667 	 * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
668 	 *       release remaining GSS contexts. This mechanism ensures
669 	 *       that it can do so safely.
670 	 */
671 	atomic_inc(&clnt->cl_count);
672 	rpcauth_release(clnt->cl_auth);
673 	clnt->cl_auth = NULL;
674 	if (atomic_dec_and_test(&clnt->cl_count))
675 		rpc_free_client(clnt);
676 }
677 
678 /*
679  * Release reference to the RPC client
680  */
681 void
682 rpc_release_client(struct rpc_clnt *clnt)
683 {
684 	dprintk("RPC:       rpc_release_client(%p)\n", clnt);
685 
686 	if (list_empty(&clnt->cl_tasks))
687 		wake_up(&destroy_wait);
688 	if (atomic_dec_and_test(&clnt->cl_count))
689 		rpc_free_auth(clnt);
690 }
691 
692 /**
693  * rpc_bind_new_program - bind a new RPC program to an existing client
694  * @old: old rpc_client
695  * @program: rpc program to set
696  * @vers: rpc program version
697  *
698  * Clones the rpc client and sets up a new RPC program. This is mainly
699  * of use for enabling different RPC programs to share the same transport.
700  * The Sun NFSv2/v3 ACL protocol can do this.
701  */
702 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
703 				      const struct rpc_program *program,
704 				      u32 vers)
705 {
706 	struct rpc_create_args args = {
707 		.program	= program,
708 		.prognumber	= program->number,
709 		.version	= vers,
710 		.authflavor	= old->cl_auth->au_flavor,
711 		.client_name	= old->cl_principal,
712 	};
713 	struct rpc_clnt *clnt;
714 	int err;
715 
716 	clnt = __rpc_clone_client(&args, old);
717 	if (IS_ERR(clnt))
718 		goto out;
719 	err = rpc_ping(clnt);
720 	if (err != 0) {
721 		rpc_shutdown_client(clnt);
722 		clnt = ERR_PTR(err);
723 	}
724 out:
725 	return clnt;
726 }
727 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
728 
729 void rpc_task_release_client(struct rpc_task *task)
730 {
731 	struct rpc_clnt *clnt = task->tk_client;
732 
733 	if (clnt != NULL) {
734 		/* Remove from client task list */
735 		spin_lock(&clnt->cl_lock);
736 		list_del(&task->tk_task);
737 		spin_unlock(&clnt->cl_lock);
738 		task->tk_client = NULL;
739 
740 		rpc_release_client(clnt);
741 	}
742 }
743 
744 static
745 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
746 {
747 	if (clnt != NULL) {
748 		rpc_task_release_client(task);
749 		task->tk_client = clnt;
750 		atomic_inc(&clnt->cl_count);
751 		if (clnt->cl_softrtry)
752 			task->tk_flags |= RPC_TASK_SOFT;
753 		if (sk_memalloc_socks()) {
754 			struct rpc_xprt *xprt;
755 
756 			rcu_read_lock();
757 			xprt = rcu_dereference(clnt->cl_xprt);
758 			if (xprt->swapper)
759 				task->tk_flags |= RPC_TASK_SWAPPER;
760 			rcu_read_unlock();
761 		}
762 		/* Add to the client's list of all tasks */
763 		spin_lock(&clnt->cl_lock);
764 		list_add_tail(&task->tk_task, &clnt->cl_tasks);
765 		spin_unlock(&clnt->cl_lock);
766 	}
767 }
768 
769 void rpc_task_reset_client(struct rpc_task *task, struct rpc_clnt *clnt)
770 {
771 	rpc_task_release_client(task);
772 	rpc_task_set_client(task, clnt);
773 }
774 EXPORT_SYMBOL_GPL(rpc_task_reset_client);
775 
776 
777 static void
778 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
779 {
780 	if (msg != NULL) {
781 		task->tk_msg.rpc_proc = msg->rpc_proc;
782 		task->tk_msg.rpc_argp = msg->rpc_argp;
783 		task->tk_msg.rpc_resp = msg->rpc_resp;
784 		if (msg->rpc_cred != NULL)
785 			task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
786 	}
787 }
788 
789 /*
790  * Default callback for async RPC calls
791  */
792 static void
793 rpc_default_callback(struct rpc_task *task, void *data)
794 {
795 }
796 
797 static const struct rpc_call_ops rpc_default_ops = {
798 	.rpc_call_done = rpc_default_callback,
799 };
800 
801 /**
802  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
803  * @task_setup_data: pointer to task initialisation data
804  */
805 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
806 {
807 	struct rpc_task *task;
808 
809 	task = rpc_new_task(task_setup_data);
810 	if (IS_ERR(task))
811 		goto out;
812 
813 	rpc_task_set_client(task, task_setup_data->rpc_client);
814 	rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
815 
816 	if (task->tk_action == NULL)
817 		rpc_call_start(task);
818 
819 	atomic_inc(&task->tk_count);
820 	rpc_execute(task);
821 out:
822 	return task;
823 }
824 EXPORT_SYMBOL_GPL(rpc_run_task);
825 
826 /**
827  * rpc_call_sync - Perform a synchronous RPC call
828  * @clnt: pointer to RPC client
829  * @msg: RPC call parameters
830  * @flags: RPC call flags
831  */
832 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
833 {
834 	struct rpc_task	*task;
835 	struct rpc_task_setup task_setup_data = {
836 		.rpc_client = clnt,
837 		.rpc_message = msg,
838 		.callback_ops = &rpc_default_ops,
839 		.flags = flags,
840 	};
841 	int status;
842 
843 	WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
844 	if (flags & RPC_TASK_ASYNC) {
845 		rpc_release_calldata(task_setup_data.callback_ops,
846 			task_setup_data.callback_data);
847 		return -EINVAL;
848 	}
849 
850 	task = rpc_run_task(&task_setup_data);
851 	if (IS_ERR(task))
852 		return PTR_ERR(task);
853 	status = task->tk_status;
854 	rpc_put_task(task);
855 	return status;
856 }
857 EXPORT_SYMBOL_GPL(rpc_call_sync);
858 
859 /**
860  * rpc_call_async - Perform an asynchronous RPC call
861  * @clnt: pointer to RPC client
862  * @msg: RPC call parameters
863  * @flags: RPC call flags
864  * @tk_ops: RPC call ops
865  * @data: user call data
866  */
867 int
868 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
869 	       const struct rpc_call_ops *tk_ops, void *data)
870 {
871 	struct rpc_task	*task;
872 	struct rpc_task_setup task_setup_data = {
873 		.rpc_client = clnt,
874 		.rpc_message = msg,
875 		.callback_ops = tk_ops,
876 		.callback_data = data,
877 		.flags = flags|RPC_TASK_ASYNC,
878 	};
879 
880 	task = rpc_run_task(&task_setup_data);
881 	if (IS_ERR(task))
882 		return PTR_ERR(task);
883 	rpc_put_task(task);
884 	return 0;
885 }
886 EXPORT_SYMBOL_GPL(rpc_call_async);
887 
888 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
889 /**
890  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
891  * rpc_execute against it
892  * @req: RPC request
893  * @tk_ops: RPC call ops
894  */
895 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req,
896 				const struct rpc_call_ops *tk_ops)
897 {
898 	struct rpc_task *task;
899 	struct xdr_buf *xbufp = &req->rq_snd_buf;
900 	struct rpc_task_setup task_setup_data = {
901 		.callback_ops = tk_ops,
902 	};
903 
904 	dprintk("RPC: rpc_run_bc_task req= %p\n", req);
905 	/*
906 	 * Create an rpc_task to send the data
907 	 */
908 	task = rpc_new_task(&task_setup_data);
909 	if (IS_ERR(task)) {
910 		xprt_free_bc_request(req);
911 		goto out;
912 	}
913 	task->tk_rqstp = req;
914 
915 	/*
916 	 * Set up the xdr_buf length.
917 	 * This also indicates that the buffer is XDR encoded already.
918 	 */
919 	xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
920 			xbufp->tail[0].iov_len;
921 
922 	task->tk_action = call_bc_transmit;
923 	atomic_inc(&task->tk_count);
924 	WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
925 	rpc_execute(task);
926 
927 out:
928 	dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
929 	return task;
930 }
931 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
932 
933 void
934 rpc_call_start(struct rpc_task *task)
935 {
936 	task->tk_action = call_start;
937 }
938 EXPORT_SYMBOL_GPL(rpc_call_start);
939 
940 /**
941  * rpc_peeraddr - extract remote peer address from clnt's xprt
942  * @clnt: RPC client structure
943  * @buf: target buffer
944  * @bufsize: length of target buffer
945  *
946  * Returns the number of bytes that are actually in the stored address.
947  */
948 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
949 {
950 	size_t bytes;
951 	struct rpc_xprt *xprt;
952 
953 	rcu_read_lock();
954 	xprt = rcu_dereference(clnt->cl_xprt);
955 
956 	bytes = xprt->addrlen;
957 	if (bytes > bufsize)
958 		bytes = bufsize;
959 	memcpy(buf, &xprt->addr, bytes);
960 	rcu_read_unlock();
961 
962 	return bytes;
963 }
964 EXPORT_SYMBOL_GPL(rpc_peeraddr);
965 
966 /**
967  * rpc_peeraddr2str - return remote peer address in printable format
968  * @clnt: RPC client structure
969  * @format: address format
970  *
971  * NB: the lifetime of the memory referenced by the returned pointer is
972  * the same as the rpc_xprt itself.  As long as the caller uses this
973  * pointer, it must hold the RCU read lock.
974  */
975 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
976 			     enum rpc_display_format_t format)
977 {
978 	struct rpc_xprt *xprt;
979 
980 	xprt = rcu_dereference(clnt->cl_xprt);
981 
982 	if (xprt->address_strings[format] != NULL)
983 		return xprt->address_strings[format];
984 	else
985 		return "unprintable";
986 }
987 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
988 
989 static const struct sockaddr_in rpc_inaddr_loopback = {
990 	.sin_family		= AF_INET,
991 	.sin_addr.s_addr	= htonl(INADDR_ANY),
992 };
993 
994 static const struct sockaddr_in6 rpc_in6addr_loopback = {
995 	.sin6_family		= AF_INET6,
996 	.sin6_addr		= IN6ADDR_ANY_INIT,
997 };
998 
999 /*
1000  * Try a getsockname() on a connected datagram socket.  Using a
1001  * connected datagram socket prevents leaving a socket in TIME_WAIT.
1002  * This conserves the ephemeral port number space.
1003  *
1004  * Returns zero and fills in "buf" if successful; otherwise, a
1005  * negative errno is returned.
1006  */
1007 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1008 			struct sockaddr *buf, int buflen)
1009 {
1010 	struct socket *sock;
1011 	int err;
1012 
1013 	err = __sock_create(net, sap->sa_family,
1014 				SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1015 	if (err < 0) {
1016 		dprintk("RPC:       can't create UDP socket (%d)\n", err);
1017 		goto out;
1018 	}
1019 
1020 	switch (sap->sa_family) {
1021 	case AF_INET:
1022 		err = kernel_bind(sock,
1023 				(struct sockaddr *)&rpc_inaddr_loopback,
1024 				sizeof(rpc_inaddr_loopback));
1025 		break;
1026 	case AF_INET6:
1027 		err = kernel_bind(sock,
1028 				(struct sockaddr *)&rpc_in6addr_loopback,
1029 				sizeof(rpc_in6addr_loopback));
1030 		break;
1031 	default:
1032 		err = -EAFNOSUPPORT;
1033 		goto out;
1034 	}
1035 	if (err < 0) {
1036 		dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1037 		goto out_release;
1038 	}
1039 
1040 	err = kernel_connect(sock, sap, salen, 0);
1041 	if (err < 0) {
1042 		dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1043 		goto out_release;
1044 	}
1045 
1046 	err = kernel_getsockname(sock, buf, &buflen);
1047 	if (err < 0) {
1048 		dprintk("RPC:       getsockname failed (%d)\n", err);
1049 		goto out_release;
1050 	}
1051 
1052 	err = 0;
1053 	if (buf->sa_family == AF_INET6) {
1054 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1055 		sin6->sin6_scope_id = 0;
1056 	}
1057 	dprintk("RPC:       %s succeeded\n", __func__);
1058 
1059 out_release:
1060 	sock_release(sock);
1061 out:
1062 	return err;
1063 }
1064 
1065 /*
1066  * Scraping a connected socket failed, so we don't have a useable
1067  * local address.  Fallback: generate an address that will prevent
1068  * the server from calling us back.
1069  *
1070  * Returns zero and fills in "buf" if successful; otherwise, a
1071  * negative errno is returned.
1072  */
1073 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1074 {
1075 	switch (family) {
1076 	case AF_INET:
1077 		if (buflen < sizeof(rpc_inaddr_loopback))
1078 			return -EINVAL;
1079 		memcpy(buf, &rpc_inaddr_loopback,
1080 				sizeof(rpc_inaddr_loopback));
1081 		break;
1082 	case AF_INET6:
1083 		if (buflen < sizeof(rpc_in6addr_loopback))
1084 			return -EINVAL;
1085 		memcpy(buf, &rpc_in6addr_loopback,
1086 				sizeof(rpc_in6addr_loopback));
1087 	default:
1088 		dprintk("RPC:       %s: address family not supported\n",
1089 			__func__);
1090 		return -EAFNOSUPPORT;
1091 	}
1092 	dprintk("RPC:       %s: succeeded\n", __func__);
1093 	return 0;
1094 }
1095 
1096 /**
1097  * rpc_localaddr - discover local endpoint address for an RPC client
1098  * @clnt: RPC client structure
1099  * @buf: target buffer
1100  * @buflen: size of target buffer, in bytes
1101  *
1102  * Returns zero and fills in "buf" and "buflen" if successful;
1103  * otherwise, a negative errno is returned.
1104  *
1105  * This works even if the underlying transport is not currently connected,
1106  * or if the upper layer never previously provided a source address.
1107  *
1108  * The result of this function call is transient: multiple calls in
1109  * succession may give different results, depending on how local
1110  * networking configuration changes over time.
1111  */
1112 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1113 {
1114 	struct sockaddr_storage address;
1115 	struct sockaddr *sap = (struct sockaddr *)&address;
1116 	struct rpc_xprt *xprt;
1117 	struct net *net;
1118 	size_t salen;
1119 	int err;
1120 
1121 	rcu_read_lock();
1122 	xprt = rcu_dereference(clnt->cl_xprt);
1123 	salen = xprt->addrlen;
1124 	memcpy(sap, &xprt->addr, salen);
1125 	net = get_net(xprt->xprt_net);
1126 	rcu_read_unlock();
1127 
1128 	rpc_set_port(sap, 0);
1129 	err = rpc_sockname(net, sap, salen, buf, buflen);
1130 	put_net(net);
1131 	if (err != 0)
1132 		/* Couldn't discover local address, return ANYADDR */
1133 		return rpc_anyaddr(sap->sa_family, buf, buflen);
1134 	return 0;
1135 }
1136 EXPORT_SYMBOL_GPL(rpc_localaddr);
1137 
1138 void
1139 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1140 {
1141 	struct rpc_xprt *xprt;
1142 
1143 	rcu_read_lock();
1144 	xprt = rcu_dereference(clnt->cl_xprt);
1145 	if (xprt->ops->set_buffer_size)
1146 		xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1147 	rcu_read_unlock();
1148 }
1149 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1150 
1151 /**
1152  * rpc_protocol - Get transport protocol number for an RPC client
1153  * @clnt: RPC client to query
1154  *
1155  */
1156 int rpc_protocol(struct rpc_clnt *clnt)
1157 {
1158 	int protocol;
1159 
1160 	rcu_read_lock();
1161 	protocol = rcu_dereference(clnt->cl_xprt)->prot;
1162 	rcu_read_unlock();
1163 	return protocol;
1164 }
1165 EXPORT_SYMBOL_GPL(rpc_protocol);
1166 
1167 /**
1168  * rpc_net_ns - Get the network namespace for this RPC client
1169  * @clnt: RPC client to query
1170  *
1171  */
1172 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1173 {
1174 	struct net *ret;
1175 
1176 	rcu_read_lock();
1177 	ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1178 	rcu_read_unlock();
1179 	return ret;
1180 }
1181 EXPORT_SYMBOL_GPL(rpc_net_ns);
1182 
1183 /**
1184  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1185  * @clnt: RPC client to query
1186  *
1187  * For stream transports, this is one RPC record fragment (see RFC
1188  * 1831), as we don't support multi-record requests yet.  For datagram
1189  * transports, this is the size of an IP packet minus the IP, UDP, and
1190  * RPC header sizes.
1191  */
1192 size_t rpc_max_payload(struct rpc_clnt *clnt)
1193 {
1194 	size_t ret;
1195 
1196 	rcu_read_lock();
1197 	ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1198 	rcu_read_unlock();
1199 	return ret;
1200 }
1201 EXPORT_SYMBOL_GPL(rpc_max_payload);
1202 
1203 /**
1204  * rpc_get_timeout - Get timeout for transport in units of HZ
1205  * @clnt: RPC client to query
1206  */
1207 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1208 {
1209 	unsigned long ret;
1210 
1211 	rcu_read_lock();
1212 	ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1213 	rcu_read_unlock();
1214 	return ret;
1215 }
1216 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1217 
1218 /**
1219  * rpc_force_rebind - force transport to check that remote port is unchanged
1220  * @clnt: client to rebind
1221  *
1222  */
1223 void rpc_force_rebind(struct rpc_clnt *clnt)
1224 {
1225 	if (clnt->cl_autobind) {
1226 		rcu_read_lock();
1227 		xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1228 		rcu_read_unlock();
1229 	}
1230 }
1231 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1232 
1233 /*
1234  * Restart an (async) RPC call from the call_prepare state.
1235  * Usually called from within the exit handler.
1236  */
1237 int
1238 rpc_restart_call_prepare(struct rpc_task *task)
1239 {
1240 	if (RPC_ASSASSINATED(task))
1241 		return 0;
1242 	task->tk_action = call_start;
1243 	if (task->tk_ops->rpc_call_prepare != NULL)
1244 		task->tk_action = rpc_prepare_task;
1245 	return 1;
1246 }
1247 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1248 
1249 /*
1250  * Restart an (async) RPC call. Usually called from within the
1251  * exit handler.
1252  */
1253 int
1254 rpc_restart_call(struct rpc_task *task)
1255 {
1256 	if (RPC_ASSASSINATED(task))
1257 		return 0;
1258 	task->tk_action = call_start;
1259 	return 1;
1260 }
1261 EXPORT_SYMBOL_GPL(rpc_restart_call);
1262 
1263 #ifdef RPC_DEBUG
1264 static const char *rpc_proc_name(const struct rpc_task *task)
1265 {
1266 	const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1267 
1268 	if (proc) {
1269 		if (proc->p_name)
1270 			return proc->p_name;
1271 		else
1272 			return "NULL";
1273 	} else
1274 		return "no proc";
1275 }
1276 #endif
1277 
1278 /*
1279  * 0.  Initial state
1280  *
1281  *     Other FSM states can be visited zero or more times, but
1282  *     this state is visited exactly once for each RPC.
1283  */
1284 static void
1285 call_start(struct rpc_task *task)
1286 {
1287 	struct rpc_clnt	*clnt = task->tk_client;
1288 
1289 	dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1290 			clnt->cl_protname, clnt->cl_vers,
1291 			rpc_proc_name(task),
1292 			(RPC_IS_ASYNC(task) ? "async" : "sync"));
1293 
1294 	/* Increment call count */
1295 	task->tk_msg.rpc_proc->p_count++;
1296 	clnt->cl_stats->rpccnt++;
1297 	task->tk_action = call_reserve;
1298 }
1299 
1300 /*
1301  * 1.	Reserve an RPC call slot
1302  */
1303 static void
1304 call_reserve(struct rpc_task *task)
1305 {
1306 	dprint_status(task);
1307 
1308 	task->tk_status  = 0;
1309 	task->tk_action  = call_reserveresult;
1310 	xprt_reserve(task);
1311 }
1312 
1313 static void call_retry_reserve(struct rpc_task *task);
1314 
1315 /*
1316  * 1b.	Grok the result of xprt_reserve()
1317  */
1318 static void
1319 call_reserveresult(struct rpc_task *task)
1320 {
1321 	int status = task->tk_status;
1322 
1323 	dprint_status(task);
1324 
1325 	/*
1326 	 * After a call to xprt_reserve(), we must have either
1327 	 * a request slot or else an error status.
1328 	 */
1329 	task->tk_status = 0;
1330 	if (status >= 0) {
1331 		if (task->tk_rqstp) {
1332 			task->tk_action = call_refresh;
1333 			return;
1334 		}
1335 
1336 		printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1337 				__func__, status);
1338 		rpc_exit(task, -EIO);
1339 		return;
1340 	}
1341 
1342 	/*
1343 	 * Even though there was an error, we may have acquired
1344 	 * a request slot somehow.  Make sure not to leak it.
1345 	 */
1346 	if (task->tk_rqstp) {
1347 		printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1348 				__func__, status);
1349 		xprt_release(task);
1350 	}
1351 
1352 	switch (status) {
1353 	case -ENOMEM:
1354 		rpc_delay(task, HZ >> 2);
1355 	case -EAGAIN:	/* woken up; retry */
1356 		task->tk_action = call_retry_reserve;
1357 		return;
1358 	case -EIO:	/* probably a shutdown */
1359 		break;
1360 	default:
1361 		printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1362 				__func__, status);
1363 		break;
1364 	}
1365 	rpc_exit(task, status);
1366 }
1367 
1368 /*
1369  * 1c.	Retry reserving an RPC call slot
1370  */
1371 static void
1372 call_retry_reserve(struct rpc_task *task)
1373 {
1374 	dprint_status(task);
1375 
1376 	task->tk_status  = 0;
1377 	task->tk_action  = call_reserveresult;
1378 	xprt_retry_reserve(task);
1379 }
1380 
1381 /*
1382  * 2.	Bind and/or refresh the credentials
1383  */
1384 static void
1385 call_refresh(struct rpc_task *task)
1386 {
1387 	dprint_status(task);
1388 
1389 	task->tk_action = call_refreshresult;
1390 	task->tk_status = 0;
1391 	task->tk_client->cl_stats->rpcauthrefresh++;
1392 	rpcauth_refreshcred(task);
1393 }
1394 
1395 /*
1396  * 2a.	Process the results of a credential refresh
1397  */
1398 static void
1399 call_refreshresult(struct rpc_task *task)
1400 {
1401 	int status = task->tk_status;
1402 
1403 	dprint_status(task);
1404 
1405 	task->tk_status = 0;
1406 	task->tk_action = call_refresh;
1407 	switch (status) {
1408 	case 0:
1409 		if (rpcauth_uptodatecred(task))
1410 			task->tk_action = call_allocate;
1411 		return;
1412 	case -ETIMEDOUT:
1413 		rpc_delay(task, 3*HZ);
1414 	case -EKEYEXPIRED:
1415 	case -EAGAIN:
1416 		status = -EACCES;
1417 		if (!task->tk_cred_retry)
1418 			break;
1419 		task->tk_cred_retry--;
1420 		dprintk("RPC: %5u %s: retry refresh creds\n",
1421 				task->tk_pid, __func__);
1422 		return;
1423 	}
1424 	dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1425 				task->tk_pid, __func__, status);
1426 	rpc_exit(task, status);
1427 }
1428 
1429 /*
1430  * 2b.	Allocate the buffer. For details, see sched.c:rpc_malloc.
1431  *	(Note: buffer memory is freed in xprt_release).
1432  */
1433 static void
1434 call_allocate(struct rpc_task *task)
1435 {
1436 	unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1437 	struct rpc_rqst *req = task->tk_rqstp;
1438 	struct rpc_xprt *xprt = req->rq_xprt;
1439 	struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1440 
1441 	dprint_status(task);
1442 
1443 	task->tk_status = 0;
1444 	task->tk_action = call_bind;
1445 
1446 	if (req->rq_buffer)
1447 		return;
1448 
1449 	if (proc->p_proc != 0) {
1450 		BUG_ON(proc->p_arglen == 0);
1451 		if (proc->p_decode != NULL)
1452 			BUG_ON(proc->p_replen == 0);
1453 	}
1454 
1455 	/*
1456 	 * Calculate the size (in quads) of the RPC call
1457 	 * and reply headers, and convert both values
1458 	 * to byte sizes.
1459 	 */
1460 	req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1461 	req->rq_callsize <<= 2;
1462 	req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1463 	req->rq_rcvsize <<= 2;
1464 
1465 	req->rq_buffer = xprt->ops->buf_alloc(task,
1466 					req->rq_callsize + req->rq_rcvsize);
1467 	if (req->rq_buffer != NULL)
1468 		return;
1469 
1470 	dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1471 
1472 	if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1473 		task->tk_action = call_allocate;
1474 		rpc_delay(task, HZ>>4);
1475 		return;
1476 	}
1477 
1478 	rpc_exit(task, -ERESTARTSYS);
1479 }
1480 
1481 static inline int
1482 rpc_task_need_encode(struct rpc_task *task)
1483 {
1484 	return task->tk_rqstp->rq_snd_buf.len == 0;
1485 }
1486 
1487 static inline void
1488 rpc_task_force_reencode(struct rpc_task *task)
1489 {
1490 	task->tk_rqstp->rq_snd_buf.len = 0;
1491 	task->tk_rqstp->rq_bytes_sent = 0;
1492 }
1493 
1494 static inline void
1495 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1496 {
1497 	buf->head[0].iov_base = start;
1498 	buf->head[0].iov_len = len;
1499 	buf->tail[0].iov_len = 0;
1500 	buf->page_len = 0;
1501 	buf->flags = 0;
1502 	buf->len = 0;
1503 	buf->buflen = len;
1504 }
1505 
1506 /*
1507  * 3.	Encode arguments of an RPC call
1508  */
1509 static void
1510 rpc_xdr_encode(struct rpc_task *task)
1511 {
1512 	struct rpc_rqst	*req = task->tk_rqstp;
1513 	kxdreproc_t	encode;
1514 	__be32		*p;
1515 
1516 	dprint_status(task);
1517 
1518 	rpc_xdr_buf_init(&req->rq_snd_buf,
1519 			 req->rq_buffer,
1520 			 req->rq_callsize);
1521 	rpc_xdr_buf_init(&req->rq_rcv_buf,
1522 			 (char *)req->rq_buffer + req->rq_callsize,
1523 			 req->rq_rcvsize);
1524 
1525 	p = rpc_encode_header(task);
1526 	if (p == NULL) {
1527 		printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1528 		rpc_exit(task, -EIO);
1529 		return;
1530 	}
1531 
1532 	encode = task->tk_msg.rpc_proc->p_encode;
1533 	if (encode == NULL)
1534 		return;
1535 
1536 	task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1537 			task->tk_msg.rpc_argp);
1538 }
1539 
1540 /*
1541  * 4.	Get the server port number if not yet set
1542  */
1543 static void
1544 call_bind(struct rpc_task *task)
1545 {
1546 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1547 
1548 	dprint_status(task);
1549 
1550 	task->tk_action = call_connect;
1551 	if (!xprt_bound(xprt)) {
1552 		task->tk_action = call_bind_status;
1553 		task->tk_timeout = xprt->bind_timeout;
1554 		xprt->ops->rpcbind(task);
1555 	}
1556 }
1557 
1558 /*
1559  * 4a.	Sort out bind result
1560  */
1561 static void
1562 call_bind_status(struct rpc_task *task)
1563 {
1564 	int status = -EIO;
1565 
1566 	if (task->tk_status >= 0) {
1567 		dprint_status(task);
1568 		task->tk_status = 0;
1569 		task->tk_action = call_connect;
1570 		return;
1571 	}
1572 
1573 	trace_rpc_bind_status(task);
1574 	switch (task->tk_status) {
1575 	case -ENOMEM:
1576 		dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1577 		rpc_delay(task, HZ >> 2);
1578 		goto retry_timeout;
1579 	case -EACCES:
1580 		dprintk("RPC: %5u remote rpcbind: RPC program/version "
1581 				"unavailable\n", task->tk_pid);
1582 		/* fail immediately if this is an RPC ping */
1583 		if (task->tk_msg.rpc_proc->p_proc == 0) {
1584 			status = -EOPNOTSUPP;
1585 			break;
1586 		}
1587 		if (task->tk_rebind_retry == 0)
1588 			break;
1589 		task->tk_rebind_retry--;
1590 		rpc_delay(task, 3*HZ);
1591 		goto retry_timeout;
1592 	case -ETIMEDOUT:
1593 		dprintk("RPC: %5u rpcbind request timed out\n",
1594 				task->tk_pid);
1595 		goto retry_timeout;
1596 	case -EPFNOSUPPORT:
1597 		/* server doesn't support any rpcbind version we know of */
1598 		dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1599 				task->tk_pid);
1600 		break;
1601 	case -EPROTONOSUPPORT:
1602 		dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1603 				task->tk_pid);
1604 		task->tk_status = 0;
1605 		task->tk_action = call_bind;
1606 		return;
1607 	case -ECONNREFUSED:		/* connection problems */
1608 	case -ECONNRESET:
1609 	case -ENOTCONN:
1610 	case -EHOSTDOWN:
1611 	case -EHOSTUNREACH:
1612 	case -ENETUNREACH:
1613 	case -EPIPE:
1614 		dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1615 				task->tk_pid, task->tk_status);
1616 		if (!RPC_IS_SOFTCONN(task)) {
1617 			rpc_delay(task, 5*HZ);
1618 			goto retry_timeout;
1619 		}
1620 		status = task->tk_status;
1621 		break;
1622 	default:
1623 		dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1624 				task->tk_pid, -task->tk_status);
1625 	}
1626 
1627 	rpc_exit(task, status);
1628 	return;
1629 
1630 retry_timeout:
1631 	task->tk_action = call_timeout;
1632 }
1633 
1634 /*
1635  * 4b.	Connect to the RPC server
1636  */
1637 static void
1638 call_connect(struct rpc_task *task)
1639 {
1640 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1641 
1642 	dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1643 			task->tk_pid, xprt,
1644 			(xprt_connected(xprt) ? "is" : "is not"));
1645 
1646 	task->tk_action = call_transmit;
1647 	if (!xprt_connected(xprt)) {
1648 		task->tk_action = call_connect_status;
1649 		if (task->tk_status < 0)
1650 			return;
1651 		xprt_connect(task);
1652 	}
1653 }
1654 
1655 /*
1656  * 4c.	Sort out connect result
1657  */
1658 static void
1659 call_connect_status(struct rpc_task *task)
1660 {
1661 	struct rpc_clnt *clnt = task->tk_client;
1662 	int status = task->tk_status;
1663 
1664 	dprint_status(task);
1665 
1666 	trace_rpc_connect_status(task, status);
1667 	switch (status) {
1668 		/* if soft mounted, test if we've timed out */
1669 	case -ETIMEDOUT:
1670 		task->tk_action = call_timeout;
1671 		return;
1672 	case -ECONNREFUSED:
1673 	case -ECONNRESET:
1674 	case -ENETUNREACH:
1675 		if (RPC_IS_SOFTCONN(task))
1676 			break;
1677 		/* retry with existing socket, after a delay */
1678 	case 0:
1679 	case -EAGAIN:
1680 		task->tk_status = 0;
1681 		clnt->cl_stats->netreconn++;
1682 		task->tk_action = call_transmit;
1683 		return;
1684 	}
1685 	rpc_exit(task, status);
1686 }
1687 
1688 /*
1689  * 5.	Transmit the RPC request, and wait for reply
1690  */
1691 static void
1692 call_transmit(struct rpc_task *task)
1693 {
1694 	dprint_status(task);
1695 
1696 	task->tk_action = call_status;
1697 	if (task->tk_status < 0)
1698 		return;
1699 	task->tk_status = xprt_prepare_transmit(task);
1700 	if (task->tk_status != 0)
1701 		return;
1702 	task->tk_action = call_transmit_status;
1703 	/* Encode here so that rpcsec_gss can use correct sequence number. */
1704 	if (rpc_task_need_encode(task)) {
1705 		rpc_xdr_encode(task);
1706 		/* Did the encode result in an error condition? */
1707 		if (task->tk_status != 0) {
1708 			/* Was the error nonfatal? */
1709 			if (task->tk_status == -EAGAIN)
1710 				rpc_delay(task, HZ >> 4);
1711 			else
1712 				rpc_exit(task, task->tk_status);
1713 			return;
1714 		}
1715 	}
1716 	xprt_transmit(task);
1717 	if (task->tk_status < 0)
1718 		return;
1719 	/*
1720 	 * On success, ensure that we call xprt_end_transmit() before sleeping
1721 	 * in order to allow access to the socket to other RPC requests.
1722 	 */
1723 	call_transmit_status(task);
1724 	if (rpc_reply_expected(task))
1725 		return;
1726 	task->tk_action = rpc_exit_task;
1727 	rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1728 }
1729 
1730 /*
1731  * 5a.	Handle cleanup after a transmission
1732  */
1733 static void
1734 call_transmit_status(struct rpc_task *task)
1735 {
1736 	task->tk_action = call_status;
1737 
1738 	/*
1739 	 * Common case: success.  Force the compiler to put this
1740 	 * test first.
1741 	 */
1742 	if (task->tk_status == 0) {
1743 		xprt_end_transmit(task);
1744 		rpc_task_force_reencode(task);
1745 		return;
1746 	}
1747 
1748 	switch (task->tk_status) {
1749 	case -EAGAIN:
1750 		break;
1751 	default:
1752 		dprint_status(task);
1753 		xprt_end_transmit(task);
1754 		rpc_task_force_reencode(task);
1755 		break;
1756 		/*
1757 		 * Special cases: if we've been waiting on the
1758 		 * socket's write_space() callback, or if the
1759 		 * socket just returned a connection error,
1760 		 * then hold onto the transport lock.
1761 		 */
1762 	case -ECONNREFUSED:
1763 	case -EHOSTDOWN:
1764 	case -EHOSTUNREACH:
1765 	case -ENETUNREACH:
1766 		if (RPC_IS_SOFTCONN(task)) {
1767 			xprt_end_transmit(task);
1768 			rpc_exit(task, task->tk_status);
1769 			break;
1770 		}
1771 	case -ECONNRESET:
1772 	case -ENOTCONN:
1773 	case -EPIPE:
1774 		rpc_task_force_reencode(task);
1775 	}
1776 }
1777 
1778 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1779 /*
1780  * 5b.	Send the backchannel RPC reply.  On error, drop the reply.  In
1781  * addition, disconnect on connectivity errors.
1782  */
1783 static void
1784 call_bc_transmit(struct rpc_task *task)
1785 {
1786 	struct rpc_rqst *req = task->tk_rqstp;
1787 
1788 	task->tk_status = xprt_prepare_transmit(task);
1789 	if (task->tk_status == -EAGAIN) {
1790 		/*
1791 		 * Could not reserve the transport. Try again after the
1792 		 * transport is released.
1793 		 */
1794 		task->tk_status = 0;
1795 		task->tk_action = call_bc_transmit;
1796 		return;
1797 	}
1798 
1799 	task->tk_action = rpc_exit_task;
1800 	if (task->tk_status < 0) {
1801 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1802 			"error: %d\n", task->tk_status);
1803 		return;
1804 	}
1805 
1806 	xprt_transmit(task);
1807 	xprt_end_transmit(task);
1808 	dprint_status(task);
1809 	switch (task->tk_status) {
1810 	case 0:
1811 		/* Success */
1812 		break;
1813 	case -EHOSTDOWN:
1814 	case -EHOSTUNREACH:
1815 	case -ENETUNREACH:
1816 	case -ETIMEDOUT:
1817 		/*
1818 		 * Problem reaching the server.  Disconnect and let the
1819 		 * forechannel reestablish the connection.  The server will
1820 		 * have to retransmit the backchannel request and we'll
1821 		 * reprocess it.  Since these ops are idempotent, there's no
1822 		 * need to cache our reply at this time.
1823 		 */
1824 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1825 			"error: %d\n", task->tk_status);
1826 		xprt_conditional_disconnect(req->rq_xprt,
1827 			req->rq_connect_cookie);
1828 		break;
1829 	default:
1830 		/*
1831 		 * We were unable to reply and will have to drop the
1832 		 * request.  The server should reconnect and retransmit.
1833 		 */
1834 		WARN_ON_ONCE(task->tk_status == -EAGAIN);
1835 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
1836 			"error: %d\n", task->tk_status);
1837 		break;
1838 	}
1839 	rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
1840 }
1841 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1842 
1843 /*
1844  * 6.	Sort out the RPC call status
1845  */
1846 static void
1847 call_status(struct rpc_task *task)
1848 {
1849 	struct rpc_clnt	*clnt = task->tk_client;
1850 	struct rpc_rqst	*req = task->tk_rqstp;
1851 	int		status;
1852 
1853 	if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
1854 		task->tk_status = req->rq_reply_bytes_recvd;
1855 
1856 	dprint_status(task);
1857 
1858 	status = task->tk_status;
1859 	if (status >= 0) {
1860 		task->tk_action = call_decode;
1861 		return;
1862 	}
1863 
1864 	trace_rpc_call_status(task);
1865 	task->tk_status = 0;
1866 	switch(status) {
1867 	case -EHOSTDOWN:
1868 	case -EHOSTUNREACH:
1869 	case -ENETUNREACH:
1870 		/*
1871 		 * Delay any retries for 3 seconds, then handle as if it
1872 		 * were a timeout.
1873 		 */
1874 		rpc_delay(task, 3*HZ);
1875 	case -ETIMEDOUT:
1876 		task->tk_action = call_timeout;
1877 		if (task->tk_client->cl_discrtry)
1878 			xprt_conditional_disconnect(req->rq_xprt,
1879 					req->rq_connect_cookie);
1880 		break;
1881 	case -ECONNRESET:
1882 	case -ECONNREFUSED:
1883 		rpc_force_rebind(clnt);
1884 		rpc_delay(task, 3*HZ);
1885 	case -EPIPE:
1886 	case -ENOTCONN:
1887 		task->tk_action = call_bind;
1888 		break;
1889 	case -EAGAIN:
1890 		task->tk_action = call_transmit;
1891 		break;
1892 	case -EIO:
1893 		/* shutdown or soft timeout */
1894 		rpc_exit(task, status);
1895 		break;
1896 	default:
1897 		if (clnt->cl_chatty)
1898 			printk("%s: RPC call returned error %d\n",
1899 			       clnt->cl_protname, -status);
1900 		rpc_exit(task, status);
1901 	}
1902 }
1903 
1904 /*
1905  * 6a.	Handle RPC timeout
1906  * 	We do not release the request slot, so we keep using the
1907  *	same XID for all retransmits.
1908  */
1909 static void
1910 call_timeout(struct rpc_task *task)
1911 {
1912 	struct rpc_clnt	*clnt = task->tk_client;
1913 
1914 	if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
1915 		dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
1916 		goto retry;
1917 	}
1918 
1919 	dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
1920 	task->tk_timeouts++;
1921 
1922 	if (RPC_IS_SOFTCONN(task)) {
1923 		rpc_exit(task, -ETIMEDOUT);
1924 		return;
1925 	}
1926 	if (RPC_IS_SOFT(task)) {
1927 		if (clnt->cl_chatty) {
1928 			rcu_read_lock();
1929 			printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
1930 				clnt->cl_protname,
1931 				rcu_dereference(clnt->cl_xprt)->servername);
1932 			rcu_read_unlock();
1933 		}
1934 		if (task->tk_flags & RPC_TASK_TIMEOUT)
1935 			rpc_exit(task, -ETIMEDOUT);
1936 		else
1937 			rpc_exit(task, -EIO);
1938 		return;
1939 	}
1940 
1941 	if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
1942 		task->tk_flags |= RPC_CALL_MAJORSEEN;
1943 		if (clnt->cl_chatty) {
1944 			rcu_read_lock();
1945 			printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
1946 			clnt->cl_protname,
1947 			rcu_dereference(clnt->cl_xprt)->servername);
1948 			rcu_read_unlock();
1949 		}
1950 	}
1951 	rpc_force_rebind(clnt);
1952 	/*
1953 	 * Did our request time out due to an RPCSEC_GSS out-of-sequence
1954 	 * event? RFC2203 requires the server to drop all such requests.
1955 	 */
1956 	rpcauth_invalcred(task);
1957 
1958 retry:
1959 	clnt->cl_stats->rpcretrans++;
1960 	task->tk_action = call_bind;
1961 	task->tk_status = 0;
1962 }
1963 
1964 /*
1965  * 7.	Decode the RPC reply
1966  */
1967 static void
1968 call_decode(struct rpc_task *task)
1969 {
1970 	struct rpc_clnt	*clnt = task->tk_client;
1971 	struct rpc_rqst	*req = task->tk_rqstp;
1972 	kxdrdproc_t	decode = task->tk_msg.rpc_proc->p_decode;
1973 	__be32		*p;
1974 
1975 	dprint_status(task);
1976 
1977 	if (task->tk_flags & RPC_CALL_MAJORSEEN) {
1978 		if (clnt->cl_chatty) {
1979 			rcu_read_lock();
1980 			printk(KERN_NOTICE "%s: server %s OK\n",
1981 				clnt->cl_protname,
1982 				rcu_dereference(clnt->cl_xprt)->servername);
1983 			rcu_read_unlock();
1984 		}
1985 		task->tk_flags &= ~RPC_CALL_MAJORSEEN;
1986 	}
1987 
1988 	/*
1989 	 * Ensure that we see all writes made by xprt_complete_rqst()
1990 	 * before it changed req->rq_reply_bytes_recvd.
1991 	 */
1992 	smp_rmb();
1993 	req->rq_rcv_buf.len = req->rq_private_buf.len;
1994 
1995 	/* Check that the softirq receive buffer is valid */
1996 	WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
1997 				sizeof(req->rq_rcv_buf)) != 0);
1998 
1999 	if (req->rq_rcv_buf.len < 12) {
2000 		if (!RPC_IS_SOFT(task)) {
2001 			task->tk_action = call_bind;
2002 			clnt->cl_stats->rpcretrans++;
2003 			goto out_retry;
2004 		}
2005 		dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2006 				clnt->cl_protname, task->tk_status);
2007 		task->tk_action = call_timeout;
2008 		goto out_retry;
2009 	}
2010 
2011 	p = rpc_verify_header(task);
2012 	if (IS_ERR(p)) {
2013 		if (p == ERR_PTR(-EAGAIN))
2014 			goto out_retry;
2015 		return;
2016 	}
2017 
2018 	task->tk_action = rpc_exit_task;
2019 
2020 	if (decode) {
2021 		task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2022 						      task->tk_msg.rpc_resp);
2023 	}
2024 	dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2025 			task->tk_status);
2026 	return;
2027 out_retry:
2028 	task->tk_status = 0;
2029 	/* Note: rpc_verify_header() may have freed the RPC slot */
2030 	if (task->tk_rqstp == req) {
2031 		req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2032 		if (task->tk_client->cl_discrtry)
2033 			xprt_conditional_disconnect(req->rq_xprt,
2034 					req->rq_connect_cookie);
2035 	}
2036 }
2037 
2038 static __be32 *
2039 rpc_encode_header(struct rpc_task *task)
2040 {
2041 	struct rpc_clnt *clnt = task->tk_client;
2042 	struct rpc_rqst	*req = task->tk_rqstp;
2043 	__be32		*p = req->rq_svec[0].iov_base;
2044 
2045 	/* FIXME: check buffer size? */
2046 
2047 	p = xprt_skip_transport_header(req->rq_xprt, p);
2048 	*p++ = req->rq_xid;		/* XID */
2049 	*p++ = htonl(RPC_CALL);		/* CALL */
2050 	*p++ = htonl(RPC_VERSION);	/* RPC version */
2051 	*p++ = htonl(clnt->cl_prog);	/* program number */
2052 	*p++ = htonl(clnt->cl_vers);	/* program version */
2053 	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */
2054 	p = rpcauth_marshcred(task, p);
2055 	req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2056 	return p;
2057 }
2058 
2059 static __be32 *
2060 rpc_verify_header(struct rpc_task *task)
2061 {
2062 	struct rpc_clnt *clnt = task->tk_client;
2063 	struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2064 	int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2065 	__be32	*p = iov->iov_base;
2066 	u32 n;
2067 	int error = -EACCES;
2068 
2069 	if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2070 		/* RFC-1014 says that the representation of XDR data must be a
2071 		 * multiple of four bytes
2072 		 * - if it isn't pointer subtraction in the NFS client may give
2073 		 *   undefined results
2074 		 */
2075 		dprintk("RPC: %5u %s: XDR representation not a multiple of"
2076 		       " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2077 		       task->tk_rqstp->rq_rcv_buf.len);
2078 		goto out_eio;
2079 	}
2080 	if ((len -= 3) < 0)
2081 		goto out_overflow;
2082 
2083 	p += 1; /* skip XID */
2084 	if ((n = ntohl(*p++)) != RPC_REPLY) {
2085 		dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2086 			task->tk_pid, __func__, n);
2087 		goto out_garbage;
2088 	}
2089 
2090 	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2091 		if (--len < 0)
2092 			goto out_overflow;
2093 		switch ((n = ntohl(*p++))) {
2094 		case RPC_AUTH_ERROR:
2095 			break;
2096 		case RPC_MISMATCH:
2097 			dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2098 				task->tk_pid, __func__);
2099 			error = -EPROTONOSUPPORT;
2100 			goto out_err;
2101 		default:
2102 			dprintk("RPC: %5u %s: RPC call rejected, "
2103 				"unknown error: %x\n",
2104 				task->tk_pid, __func__, n);
2105 			goto out_eio;
2106 		}
2107 		if (--len < 0)
2108 			goto out_overflow;
2109 		switch ((n = ntohl(*p++))) {
2110 		case RPC_AUTH_REJECTEDCRED:
2111 		case RPC_AUTH_REJECTEDVERF:
2112 		case RPCSEC_GSS_CREDPROBLEM:
2113 		case RPCSEC_GSS_CTXPROBLEM:
2114 			if (!task->tk_cred_retry)
2115 				break;
2116 			task->tk_cred_retry--;
2117 			dprintk("RPC: %5u %s: retry stale creds\n",
2118 					task->tk_pid, __func__);
2119 			rpcauth_invalcred(task);
2120 			/* Ensure we obtain a new XID! */
2121 			xprt_release(task);
2122 			task->tk_action = call_reserve;
2123 			goto out_retry;
2124 		case RPC_AUTH_BADCRED:
2125 		case RPC_AUTH_BADVERF:
2126 			/* possibly garbled cred/verf? */
2127 			if (!task->tk_garb_retry)
2128 				break;
2129 			task->tk_garb_retry--;
2130 			dprintk("RPC: %5u %s: retry garbled creds\n",
2131 					task->tk_pid, __func__);
2132 			task->tk_action = call_bind;
2133 			goto out_retry;
2134 		case RPC_AUTH_TOOWEAK:
2135 			rcu_read_lock();
2136 			printk(KERN_NOTICE "RPC: server %s requires stronger "
2137 			       "authentication.\n",
2138 			       rcu_dereference(clnt->cl_xprt)->servername);
2139 			rcu_read_unlock();
2140 			break;
2141 		default:
2142 			dprintk("RPC: %5u %s: unknown auth error: %x\n",
2143 					task->tk_pid, __func__, n);
2144 			error = -EIO;
2145 		}
2146 		dprintk("RPC: %5u %s: call rejected %d\n",
2147 				task->tk_pid, __func__, n);
2148 		goto out_err;
2149 	}
2150 	if (!(p = rpcauth_checkverf(task, p))) {
2151 		dprintk("RPC: %5u %s: auth check failed\n",
2152 				task->tk_pid, __func__);
2153 		goto out_garbage;		/* bad verifier, retry */
2154 	}
2155 	len = p - (__be32 *)iov->iov_base - 1;
2156 	if (len < 0)
2157 		goto out_overflow;
2158 	switch ((n = ntohl(*p++))) {
2159 	case RPC_SUCCESS:
2160 		return p;
2161 	case RPC_PROG_UNAVAIL:
2162 		dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2163 				"by server %s\n", task->tk_pid, __func__,
2164 				(unsigned int)clnt->cl_prog,
2165 				rcu_dereference(clnt->cl_xprt)->servername);
2166 		error = -EPFNOSUPPORT;
2167 		goto out_err;
2168 	case RPC_PROG_MISMATCH:
2169 		dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2170 				"by server %s\n", task->tk_pid, __func__,
2171 				(unsigned int)clnt->cl_prog,
2172 				(unsigned int)clnt->cl_vers,
2173 				rcu_dereference(clnt->cl_xprt)->servername);
2174 		error = -EPROTONOSUPPORT;
2175 		goto out_err;
2176 	case RPC_PROC_UNAVAIL:
2177 		dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2178 				"version %u on server %s\n",
2179 				task->tk_pid, __func__,
2180 				rpc_proc_name(task),
2181 				clnt->cl_prog, clnt->cl_vers,
2182 				rcu_dereference(clnt->cl_xprt)->servername);
2183 		error = -EOPNOTSUPP;
2184 		goto out_err;
2185 	case RPC_GARBAGE_ARGS:
2186 		dprintk("RPC: %5u %s: server saw garbage\n",
2187 				task->tk_pid, __func__);
2188 		break;			/* retry */
2189 	default:
2190 		dprintk("RPC: %5u %s: server accept status: %x\n",
2191 				task->tk_pid, __func__, n);
2192 		/* Also retry */
2193 	}
2194 
2195 out_garbage:
2196 	clnt->cl_stats->rpcgarbage++;
2197 	if (task->tk_garb_retry) {
2198 		task->tk_garb_retry--;
2199 		dprintk("RPC: %5u %s: retrying\n",
2200 				task->tk_pid, __func__);
2201 		task->tk_action = call_bind;
2202 out_retry:
2203 		return ERR_PTR(-EAGAIN);
2204 	}
2205 out_eio:
2206 	error = -EIO;
2207 out_err:
2208 	rpc_exit(task, error);
2209 	dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2210 			__func__, error);
2211 	return ERR_PTR(error);
2212 out_overflow:
2213 	dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2214 			__func__);
2215 	goto out_garbage;
2216 }
2217 
2218 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2219 {
2220 }
2221 
2222 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2223 {
2224 	return 0;
2225 }
2226 
2227 static struct rpc_procinfo rpcproc_null = {
2228 	.p_encode = rpcproc_encode_null,
2229 	.p_decode = rpcproc_decode_null,
2230 };
2231 
2232 static int rpc_ping(struct rpc_clnt *clnt)
2233 {
2234 	struct rpc_message msg = {
2235 		.rpc_proc = &rpcproc_null,
2236 	};
2237 	int err;
2238 	msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2239 	err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2240 	put_rpccred(msg.rpc_cred);
2241 	return err;
2242 }
2243 
2244 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2245 {
2246 	struct rpc_message msg = {
2247 		.rpc_proc = &rpcproc_null,
2248 		.rpc_cred = cred,
2249 	};
2250 	struct rpc_task_setup task_setup_data = {
2251 		.rpc_client = clnt,
2252 		.rpc_message = &msg,
2253 		.callback_ops = &rpc_default_ops,
2254 		.flags = flags,
2255 	};
2256 	return rpc_run_task(&task_setup_data);
2257 }
2258 EXPORT_SYMBOL_GPL(rpc_call_null);
2259 
2260 #ifdef RPC_DEBUG
2261 static void rpc_show_header(void)
2262 {
2263 	printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2264 		"-timeout ---ops--\n");
2265 }
2266 
2267 static void rpc_show_task(const struct rpc_clnt *clnt,
2268 			  const struct rpc_task *task)
2269 {
2270 	const char *rpc_waitq = "none";
2271 
2272 	if (RPC_IS_QUEUED(task))
2273 		rpc_waitq = rpc_qname(task->tk_waitqueue);
2274 
2275 	printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2276 		task->tk_pid, task->tk_flags, task->tk_status,
2277 		clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2278 		clnt->cl_protname, clnt->cl_vers, rpc_proc_name(task),
2279 		task->tk_action, rpc_waitq);
2280 }
2281 
2282 void rpc_show_tasks(struct net *net)
2283 {
2284 	struct rpc_clnt *clnt;
2285 	struct rpc_task *task;
2286 	int header = 0;
2287 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2288 
2289 	spin_lock(&sn->rpc_client_lock);
2290 	list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2291 		spin_lock(&clnt->cl_lock);
2292 		list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2293 			if (!header) {
2294 				rpc_show_header();
2295 				header++;
2296 			}
2297 			rpc_show_task(clnt, task);
2298 		}
2299 		spin_unlock(&clnt->cl_lock);
2300 	}
2301 	spin_unlock(&sn->rpc_client_lock);
2302 }
2303 #endif
2304