xref: /linux/net/sunrpc/clnt.c (revision 4246b92cf9fb32da8d8b060c92d8302797c6fbea)
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/rcupdate.h>
29 #include <linux/utsname.h>
30 #include <linux/workqueue.h>
31 #include <linux/in.h>
32 #include <linux/in6.h>
33 #include <linux/un.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 #if IS_ENABLED(CONFIG_SUNRPC_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 	rpc_remove_client_dir(clnt);
106 }
107 
108 static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
109 {
110 	struct net *net = rpc_net_ns(clnt);
111 	struct super_block *pipefs_sb;
112 
113 	pipefs_sb = rpc_get_sb_net(net);
114 	if (pipefs_sb) {
115 		__rpc_clnt_remove_pipedir(clnt);
116 		rpc_put_sb_net(net);
117 	}
118 }
119 
120 static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
121 				    struct rpc_clnt *clnt)
122 {
123 	static uint32_t clntid;
124 	const char *dir_name = clnt->cl_program->pipe_dir_name;
125 	char name[15];
126 	struct dentry *dir, *dentry;
127 
128 	dir = rpc_d_lookup_sb(sb, dir_name);
129 	if (dir == NULL) {
130 		pr_info("RPC: pipefs directory doesn't exist: %s\n", dir_name);
131 		return dir;
132 	}
133 	for (;;) {
134 		snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
135 		name[sizeof(name) - 1] = '\0';
136 		dentry = rpc_create_client_dir(dir, name, clnt);
137 		if (!IS_ERR(dentry))
138 			break;
139 		if (dentry == ERR_PTR(-EEXIST))
140 			continue;
141 		printk(KERN_INFO "RPC: Couldn't create pipefs entry"
142 				" %s/%s, error %ld\n",
143 				dir_name, name, PTR_ERR(dentry));
144 		break;
145 	}
146 	dput(dir);
147 	return dentry;
148 }
149 
150 static int
151 rpc_setup_pipedir(struct super_block *pipefs_sb, struct rpc_clnt *clnt)
152 {
153 	struct dentry *dentry;
154 
155 	if (clnt->cl_program->pipe_dir_name != NULL) {
156 		dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt);
157 		if (IS_ERR(dentry))
158 			return PTR_ERR(dentry);
159 	}
160 	return 0;
161 }
162 
163 static int rpc_clnt_skip_event(struct rpc_clnt *clnt, unsigned long event)
164 {
165 	if (clnt->cl_program->pipe_dir_name == NULL)
166 		return 1;
167 
168 	switch (event) {
169 	case RPC_PIPEFS_MOUNT:
170 		if (clnt->cl_pipedir_objects.pdh_dentry != NULL)
171 			return 1;
172 		if (atomic_read(&clnt->cl_count) == 0)
173 			return 1;
174 		break;
175 	case RPC_PIPEFS_UMOUNT:
176 		if (clnt->cl_pipedir_objects.pdh_dentry == NULL)
177 			return 1;
178 		break;
179 	}
180 	return 0;
181 }
182 
183 static int __rpc_clnt_handle_event(struct rpc_clnt *clnt, unsigned long event,
184 				   struct super_block *sb)
185 {
186 	struct dentry *dentry;
187 
188 	switch (event) {
189 	case RPC_PIPEFS_MOUNT:
190 		dentry = rpc_setup_pipedir_sb(sb, clnt);
191 		if (!dentry)
192 			return -ENOENT;
193 		if (IS_ERR(dentry))
194 			return PTR_ERR(dentry);
195 		break;
196 	case RPC_PIPEFS_UMOUNT:
197 		__rpc_clnt_remove_pipedir(clnt);
198 		break;
199 	default:
200 		printk(KERN_ERR "%s: unknown event: %ld\n", __func__, event);
201 		return -ENOTSUPP;
202 	}
203 	return 0;
204 }
205 
206 static int __rpc_pipefs_event(struct rpc_clnt *clnt, unsigned long event,
207 				struct super_block *sb)
208 {
209 	int error = 0;
210 
211 	for (;; clnt = clnt->cl_parent) {
212 		if (!rpc_clnt_skip_event(clnt, event))
213 			error = __rpc_clnt_handle_event(clnt, event, sb);
214 		if (error || clnt == clnt->cl_parent)
215 			break;
216 	}
217 	return error;
218 }
219 
220 static struct rpc_clnt *rpc_get_client_for_event(struct net *net, int event)
221 {
222 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
223 	struct rpc_clnt *clnt;
224 
225 	spin_lock(&sn->rpc_client_lock);
226 	list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
227 		if (rpc_clnt_skip_event(clnt, event))
228 			continue;
229 		spin_unlock(&sn->rpc_client_lock);
230 		return clnt;
231 	}
232 	spin_unlock(&sn->rpc_client_lock);
233 	return NULL;
234 }
235 
236 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
237 			    void *ptr)
238 {
239 	struct super_block *sb = ptr;
240 	struct rpc_clnt *clnt;
241 	int error = 0;
242 
243 	while ((clnt = rpc_get_client_for_event(sb->s_fs_info, event))) {
244 		error = __rpc_pipefs_event(clnt, event, sb);
245 		if (error)
246 			break;
247 	}
248 	return error;
249 }
250 
251 static struct notifier_block rpc_clients_block = {
252 	.notifier_call	= rpc_pipefs_event,
253 	.priority	= SUNRPC_PIPEFS_RPC_PRIO,
254 };
255 
256 int rpc_clients_notifier_register(void)
257 {
258 	return rpc_pipefs_notifier_register(&rpc_clients_block);
259 }
260 
261 void rpc_clients_notifier_unregister(void)
262 {
263 	return rpc_pipefs_notifier_unregister(&rpc_clients_block);
264 }
265 
266 static struct rpc_xprt *rpc_clnt_set_transport(struct rpc_clnt *clnt,
267 		struct rpc_xprt *xprt,
268 		const struct rpc_timeout *timeout)
269 {
270 	struct rpc_xprt *old;
271 
272 	spin_lock(&clnt->cl_lock);
273 	old = rcu_dereference_protected(clnt->cl_xprt,
274 			lockdep_is_held(&clnt->cl_lock));
275 
276 	if (!xprt_bound(xprt))
277 		clnt->cl_autobind = 1;
278 
279 	clnt->cl_timeout = timeout;
280 	rcu_assign_pointer(clnt->cl_xprt, xprt);
281 	spin_unlock(&clnt->cl_lock);
282 
283 	return old;
284 }
285 
286 static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename)
287 {
288 	clnt->cl_nodelen = strlcpy(clnt->cl_nodename,
289 			nodename, sizeof(clnt->cl_nodename));
290 }
291 
292 static int rpc_client_register(struct rpc_clnt *clnt,
293 			       rpc_authflavor_t pseudoflavor,
294 			       const char *client_name)
295 {
296 	struct rpc_auth_create_args auth_args = {
297 		.pseudoflavor = pseudoflavor,
298 		.target_name = client_name,
299 	};
300 	struct rpc_auth *auth;
301 	struct net *net = rpc_net_ns(clnt);
302 	struct super_block *pipefs_sb;
303 	int err;
304 
305 	rpc_clnt_debugfs_register(clnt);
306 
307 	pipefs_sb = rpc_get_sb_net(net);
308 	if (pipefs_sb) {
309 		err = rpc_setup_pipedir(pipefs_sb, clnt);
310 		if (err)
311 			goto out;
312 	}
313 
314 	rpc_register_client(clnt);
315 	if (pipefs_sb)
316 		rpc_put_sb_net(net);
317 
318 	auth = rpcauth_create(&auth_args, clnt);
319 	if (IS_ERR(auth)) {
320 		dprintk("RPC:       Couldn't create auth handle (flavor %u)\n",
321 				pseudoflavor);
322 		err = PTR_ERR(auth);
323 		goto err_auth;
324 	}
325 	return 0;
326 err_auth:
327 	pipefs_sb = rpc_get_sb_net(net);
328 	rpc_unregister_client(clnt);
329 	__rpc_clnt_remove_pipedir(clnt);
330 out:
331 	if (pipefs_sb)
332 		rpc_put_sb_net(net);
333 	rpc_clnt_debugfs_unregister(clnt);
334 	return err;
335 }
336 
337 static DEFINE_IDA(rpc_clids);
338 
339 void rpc_cleanup_clids(void)
340 {
341 	ida_destroy(&rpc_clids);
342 }
343 
344 static int rpc_alloc_clid(struct rpc_clnt *clnt)
345 {
346 	int clid;
347 
348 	clid = ida_simple_get(&rpc_clids, 0, 0, GFP_KERNEL);
349 	if (clid < 0)
350 		return clid;
351 	clnt->cl_clid = clid;
352 	return 0;
353 }
354 
355 static void rpc_free_clid(struct rpc_clnt *clnt)
356 {
357 	ida_simple_remove(&rpc_clids, clnt->cl_clid);
358 }
359 
360 static struct rpc_clnt * rpc_new_client(const struct rpc_create_args *args,
361 		struct rpc_xprt_switch *xps,
362 		struct rpc_xprt *xprt,
363 		struct rpc_clnt *parent)
364 {
365 	const struct rpc_program *program = args->program;
366 	const struct rpc_version *version;
367 	struct rpc_clnt *clnt = NULL;
368 	const struct rpc_timeout *timeout;
369 	const char *nodename = args->nodename;
370 	int err;
371 
372 	/* sanity check the name before trying to print it */
373 	dprintk("RPC:       creating %s client for %s (xprt %p)\n",
374 			program->name, args->servername, xprt);
375 
376 	err = rpciod_up();
377 	if (err)
378 		goto out_no_rpciod;
379 
380 	err = -EINVAL;
381 	if (args->version >= program->nrvers)
382 		goto out_err;
383 	version = program->version[args->version];
384 	if (version == NULL)
385 		goto out_err;
386 
387 	err = -ENOMEM;
388 	clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
389 	if (!clnt)
390 		goto out_err;
391 	clnt->cl_parent = parent ? : clnt;
392 
393 	err = rpc_alloc_clid(clnt);
394 	if (err)
395 		goto out_no_clid;
396 
397 	clnt->cl_procinfo = version->procs;
398 	clnt->cl_maxproc  = version->nrprocs;
399 	clnt->cl_prog     = args->prognumber ? : program->number;
400 	clnt->cl_vers     = version->number;
401 	clnt->cl_stats    = program->stats;
402 	clnt->cl_metrics  = rpc_alloc_iostats(clnt);
403 	rpc_init_pipe_dir_head(&clnt->cl_pipedir_objects);
404 	err = -ENOMEM;
405 	if (clnt->cl_metrics == NULL)
406 		goto out_no_stats;
407 	clnt->cl_program  = program;
408 	INIT_LIST_HEAD(&clnt->cl_tasks);
409 	spin_lock_init(&clnt->cl_lock);
410 
411 	timeout = xprt->timeout;
412 	if (args->timeout != NULL) {
413 		memcpy(&clnt->cl_timeout_default, args->timeout,
414 				sizeof(clnt->cl_timeout_default));
415 		timeout = &clnt->cl_timeout_default;
416 	}
417 
418 	rpc_clnt_set_transport(clnt, xprt, timeout);
419 	xprt_iter_init(&clnt->cl_xpi, xps);
420 	xprt_switch_put(xps);
421 
422 	clnt->cl_rtt = &clnt->cl_rtt_default;
423 	rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
424 
425 	atomic_set(&clnt->cl_count, 1);
426 
427 	if (nodename == NULL)
428 		nodename = utsname()->nodename;
429 	/* save the nodename */
430 	rpc_clnt_set_nodename(clnt, nodename);
431 
432 	err = rpc_client_register(clnt, args->authflavor, args->client_name);
433 	if (err)
434 		goto out_no_path;
435 	if (parent)
436 		atomic_inc(&parent->cl_count);
437 	return clnt;
438 
439 out_no_path:
440 	rpc_free_iostats(clnt->cl_metrics);
441 out_no_stats:
442 	rpc_free_clid(clnt);
443 out_no_clid:
444 	kfree(clnt);
445 out_err:
446 	rpciod_down();
447 out_no_rpciod:
448 	xprt_switch_put(xps);
449 	xprt_put(xprt);
450 	return ERR_PTR(err);
451 }
452 
453 static struct rpc_clnt *rpc_create_xprt(struct rpc_create_args *args,
454 					struct rpc_xprt *xprt)
455 {
456 	struct rpc_clnt *clnt = NULL;
457 	struct rpc_xprt_switch *xps;
458 
459 	if (args->bc_xprt && args->bc_xprt->xpt_bc_xps) {
460 		WARN_ON_ONCE(!(args->protocol & XPRT_TRANSPORT_BC));
461 		xps = args->bc_xprt->xpt_bc_xps;
462 		xprt_switch_get(xps);
463 	} else {
464 		xps = xprt_switch_alloc(xprt, GFP_KERNEL);
465 		if (xps == NULL) {
466 			xprt_put(xprt);
467 			return ERR_PTR(-ENOMEM);
468 		}
469 		if (xprt->bc_xprt) {
470 			xprt_switch_get(xps);
471 			xprt->bc_xprt->xpt_bc_xps = xps;
472 		}
473 	}
474 	clnt = rpc_new_client(args, xps, xprt, NULL);
475 	if (IS_ERR(clnt))
476 		return clnt;
477 
478 	if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
479 		int err = rpc_ping(clnt);
480 		if (err != 0) {
481 			rpc_shutdown_client(clnt);
482 			return ERR_PTR(err);
483 		}
484 	}
485 
486 	clnt->cl_softrtry = 1;
487 	if (args->flags & RPC_CLNT_CREATE_HARDRTRY)
488 		clnt->cl_softrtry = 0;
489 
490 	if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
491 		clnt->cl_autobind = 1;
492 	if (args->flags & RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT)
493 		clnt->cl_noretranstimeo = 1;
494 	if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
495 		clnt->cl_discrtry = 1;
496 	if (!(args->flags & RPC_CLNT_CREATE_QUIET))
497 		clnt->cl_chatty = 1;
498 
499 	return clnt;
500 }
501 
502 /**
503  * rpc_create - create an RPC client and transport with one call
504  * @args: rpc_clnt create argument structure
505  *
506  * Creates and initializes an RPC transport and an RPC client.
507  *
508  * It can ping the server in order to determine if it is up, and to see if
509  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
510  * this behavior so asynchronous tasks can also use rpc_create.
511  */
512 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
513 {
514 	struct rpc_xprt *xprt;
515 	struct xprt_create xprtargs = {
516 		.net = args->net,
517 		.ident = args->protocol,
518 		.srcaddr = args->saddress,
519 		.dstaddr = args->address,
520 		.addrlen = args->addrsize,
521 		.servername = args->servername,
522 		.bc_xprt = args->bc_xprt,
523 	};
524 	char servername[48];
525 
526 	if (args->bc_xprt) {
527 		WARN_ON_ONCE(!(args->protocol & XPRT_TRANSPORT_BC));
528 		xprt = args->bc_xprt->xpt_bc_xprt;
529 		if (xprt) {
530 			xprt_get(xprt);
531 			return rpc_create_xprt(args, xprt);
532 		}
533 	}
534 
535 	if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
536 		xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
537 	if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
538 		xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
539 	/*
540 	 * If the caller chooses not to specify a hostname, whip
541 	 * up a string representation of the passed-in address.
542 	 */
543 	if (xprtargs.servername == NULL) {
544 		struct sockaddr_un *sun =
545 				(struct sockaddr_un *)args->address;
546 		struct sockaddr_in *sin =
547 				(struct sockaddr_in *)args->address;
548 		struct sockaddr_in6 *sin6 =
549 				(struct sockaddr_in6 *)args->address;
550 
551 		servername[0] = '\0';
552 		switch (args->address->sa_family) {
553 		case AF_LOCAL:
554 			snprintf(servername, sizeof(servername), "%s",
555 				 sun->sun_path);
556 			break;
557 		case AF_INET:
558 			snprintf(servername, sizeof(servername), "%pI4",
559 				 &sin->sin_addr.s_addr);
560 			break;
561 		case AF_INET6:
562 			snprintf(servername, sizeof(servername), "%pI6",
563 				 &sin6->sin6_addr);
564 			break;
565 		default:
566 			/* caller wants default server name, but
567 			 * address family isn't recognized. */
568 			return ERR_PTR(-EINVAL);
569 		}
570 		xprtargs.servername = servername;
571 	}
572 
573 	xprt = xprt_create_transport(&xprtargs);
574 	if (IS_ERR(xprt))
575 		return (struct rpc_clnt *)xprt;
576 
577 	/*
578 	 * By default, kernel RPC client connects from a reserved port.
579 	 * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
580 	 * but it is always enabled for rpciod, which handles the connect
581 	 * operation.
582 	 */
583 	xprt->resvport = 1;
584 	if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
585 		xprt->resvport = 0;
586 
587 	return rpc_create_xprt(args, xprt);
588 }
589 EXPORT_SYMBOL_GPL(rpc_create);
590 
591 /*
592  * This function clones the RPC client structure. It allows us to share the
593  * same transport while varying parameters such as the authentication
594  * flavour.
595  */
596 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
597 					   struct rpc_clnt *clnt)
598 {
599 	struct rpc_xprt_switch *xps;
600 	struct rpc_xprt *xprt;
601 	struct rpc_clnt *new;
602 	int err;
603 
604 	err = -ENOMEM;
605 	rcu_read_lock();
606 	xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
607 	xps = xprt_switch_get(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
608 	rcu_read_unlock();
609 	if (xprt == NULL || xps == NULL) {
610 		xprt_put(xprt);
611 		xprt_switch_put(xps);
612 		goto out_err;
613 	}
614 	args->servername = xprt->servername;
615 	args->nodename = clnt->cl_nodename;
616 
617 	new = rpc_new_client(args, xps, xprt, clnt);
618 	if (IS_ERR(new)) {
619 		err = PTR_ERR(new);
620 		goto out_err;
621 	}
622 
623 	/* Turn off autobind on clones */
624 	new->cl_autobind = 0;
625 	new->cl_softrtry = clnt->cl_softrtry;
626 	new->cl_noretranstimeo = clnt->cl_noretranstimeo;
627 	new->cl_discrtry = clnt->cl_discrtry;
628 	new->cl_chatty = clnt->cl_chatty;
629 	return new;
630 
631 out_err:
632 	dprintk("RPC:       %s: returned error %d\n", __func__, err);
633 	return ERR_PTR(err);
634 }
635 
636 /**
637  * rpc_clone_client - Clone an RPC client structure
638  *
639  * @clnt: RPC client whose parameters are copied
640  *
641  * Returns a fresh RPC client or an ERR_PTR.
642  */
643 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
644 {
645 	struct rpc_create_args args = {
646 		.program	= clnt->cl_program,
647 		.prognumber	= clnt->cl_prog,
648 		.version	= clnt->cl_vers,
649 		.authflavor	= clnt->cl_auth->au_flavor,
650 	};
651 	return __rpc_clone_client(&args, clnt);
652 }
653 EXPORT_SYMBOL_GPL(rpc_clone_client);
654 
655 /**
656  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
657  *
658  * @clnt: RPC client whose parameters are copied
659  * @flavor: security flavor for new client
660  *
661  * Returns a fresh RPC client or an ERR_PTR.
662  */
663 struct rpc_clnt *
664 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
665 {
666 	struct rpc_create_args args = {
667 		.program	= clnt->cl_program,
668 		.prognumber	= clnt->cl_prog,
669 		.version	= clnt->cl_vers,
670 		.authflavor	= flavor,
671 	};
672 	return __rpc_clone_client(&args, clnt);
673 }
674 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
675 
676 /**
677  * rpc_switch_client_transport: switch the RPC transport on the fly
678  * @clnt: pointer to a struct rpc_clnt
679  * @args: pointer to the new transport arguments
680  * @timeout: pointer to the new timeout parameters
681  *
682  * This function allows the caller to switch the RPC transport for the
683  * rpc_clnt structure 'clnt' to allow it to connect to a mirrored NFS
684  * server, for instance.  It assumes that the caller has ensured that
685  * there are no active RPC tasks by using some form of locking.
686  *
687  * Returns zero if "clnt" is now using the new xprt.  Otherwise a
688  * negative errno is returned, and "clnt" continues to use the old
689  * xprt.
690  */
691 int rpc_switch_client_transport(struct rpc_clnt *clnt,
692 		struct xprt_create *args,
693 		const struct rpc_timeout *timeout)
694 {
695 	const struct rpc_timeout *old_timeo;
696 	rpc_authflavor_t pseudoflavor;
697 	struct rpc_xprt_switch *xps, *oldxps;
698 	struct rpc_xprt *xprt, *old;
699 	struct rpc_clnt *parent;
700 	int err;
701 
702 	xprt = xprt_create_transport(args);
703 	if (IS_ERR(xprt)) {
704 		dprintk("RPC:       failed to create new xprt for clnt %p\n",
705 			clnt);
706 		return PTR_ERR(xprt);
707 	}
708 
709 	xps = xprt_switch_alloc(xprt, GFP_KERNEL);
710 	if (xps == NULL) {
711 		xprt_put(xprt);
712 		return -ENOMEM;
713 	}
714 
715 	pseudoflavor = clnt->cl_auth->au_flavor;
716 
717 	old_timeo = clnt->cl_timeout;
718 	old = rpc_clnt_set_transport(clnt, xprt, timeout);
719 	oldxps = xprt_iter_xchg_switch(&clnt->cl_xpi, xps);
720 
721 	rpc_unregister_client(clnt);
722 	__rpc_clnt_remove_pipedir(clnt);
723 	rpc_clnt_debugfs_unregister(clnt);
724 
725 	/*
726 	 * A new transport was created.  "clnt" therefore
727 	 * becomes the root of a new cl_parent tree.  clnt's
728 	 * children, if it has any, still point to the old xprt.
729 	 */
730 	parent = clnt->cl_parent;
731 	clnt->cl_parent = clnt;
732 
733 	/*
734 	 * The old rpc_auth cache cannot be re-used.  GSS
735 	 * contexts in particular are between a single
736 	 * client and server.
737 	 */
738 	err = rpc_client_register(clnt, pseudoflavor, NULL);
739 	if (err)
740 		goto out_revert;
741 
742 	synchronize_rcu();
743 	if (parent != clnt)
744 		rpc_release_client(parent);
745 	xprt_switch_put(oldxps);
746 	xprt_put(old);
747 	dprintk("RPC:       replaced xprt for clnt %p\n", clnt);
748 	return 0;
749 
750 out_revert:
751 	xps = xprt_iter_xchg_switch(&clnt->cl_xpi, oldxps);
752 	rpc_clnt_set_transport(clnt, old, old_timeo);
753 	clnt->cl_parent = parent;
754 	rpc_client_register(clnt, pseudoflavor, NULL);
755 	xprt_switch_put(xps);
756 	xprt_put(xprt);
757 	dprintk("RPC:       failed to switch xprt for clnt %p\n", clnt);
758 	return err;
759 }
760 EXPORT_SYMBOL_GPL(rpc_switch_client_transport);
761 
762 static
763 int rpc_clnt_xprt_iter_init(struct rpc_clnt *clnt, struct rpc_xprt_iter *xpi)
764 {
765 	struct rpc_xprt_switch *xps;
766 
767 	rcu_read_lock();
768 	xps = xprt_switch_get(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
769 	rcu_read_unlock();
770 	if (xps == NULL)
771 		return -EAGAIN;
772 	xprt_iter_init_listall(xpi, xps);
773 	xprt_switch_put(xps);
774 	return 0;
775 }
776 
777 /**
778  * rpc_clnt_iterate_for_each_xprt - Apply a function to all transports
779  * @clnt: pointer to client
780  * @fn: function to apply
781  * @data: void pointer to function data
782  *
783  * Iterates through the list of RPC transports currently attached to the
784  * client and applies the function fn(clnt, xprt, data).
785  *
786  * On error, the iteration stops, and the function returns the error value.
787  */
788 int rpc_clnt_iterate_for_each_xprt(struct rpc_clnt *clnt,
789 		int (*fn)(struct rpc_clnt *, struct rpc_xprt *, void *),
790 		void *data)
791 {
792 	struct rpc_xprt_iter xpi;
793 	int ret;
794 
795 	ret = rpc_clnt_xprt_iter_init(clnt, &xpi);
796 	if (ret)
797 		return ret;
798 	for (;;) {
799 		struct rpc_xprt *xprt = xprt_iter_get_next(&xpi);
800 
801 		if (!xprt)
802 			break;
803 		ret = fn(clnt, xprt, data);
804 		xprt_put(xprt);
805 		if (ret < 0)
806 			break;
807 	}
808 	xprt_iter_destroy(&xpi);
809 	return ret;
810 }
811 EXPORT_SYMBOL_GPL(rpc_clnt_iterate_for_each_xprt);
812 
813 /*
814  * Kill all tasks for the given client.
815  * XXX: kill their descendants as well?
816  */
817 void rpc_killall_tasks(struct rpc_clnt *clnt)
818 {
819 	struct rpc_task	*rovr;
820 
821 
822 	if (list_empty(&clnt->cl_tasks))
823 		return;
824 	dprintk("RPC:       killing all tasks for client %p\n", clnt);
825 	/*
826 	 * Spin lock all_tasks to prevent changes...
827 	 */
828 	spin_lock(&clnt->cl_lock);
829 	list_for_each_entry(rovr, &clnt->cl_tasks, tk_task) {
830 		if (!RPC_IS_ACTIVATED(rovr))
831 			continue;
832 		if (!(rovr->tk_flags & RPC_TASK_KILLED)) {
833 			rovr->tk_flags |= RPC_TASK_KILLED;
834 			rpc_exit(rovr, -EIO);
835 			if (RPC_IS_QUEUED(rovr))
836 				rpc_wake_up_queued_task(rovr->tk_waitqueue,
837 							rovr);
838 		}
839 	}
840 	spin_unlock(&clnt->cl_lock);
841 }
842 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
843 
844 /*
845  * Properly shut down an RPC client, terminating all outstanding
846  * requests.
847  */
848 void rpc_shutdown_client(struct rpc_clnt *clnt)
849 {
850 	might_sleep();
851 
852 	dprintk_rcu("RPC:       shutting down %s client for %s\n",
853 			clnt->cl_program->name,
854 			rcu_dereference(clnt->cl_xprt)->servername);
855 
856 	while (!list_empty(&clnt->cl_tasks)) {
857 		rpc_killall_tasks(clnt);
858 		wait_event_timeout(destroy_wait,
859 			list_empty(&clnt->cl_tasks), 1*HZ);
860 	}
861 
862 	rpc_release_client(clnt);
863 }
864 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
865 
866 /*
867  * Free an RPC client
868  */
869 static struct rpc_clnt *
870 rpc_free_client(struct rpc_clnt *clnt)
871 {
872 	struct rpc_clnt *parent = NULL;
873 
874 	dprintk_rcu("RPC:       destroying %s client for %s\n",
875 			clnt->cl_program->name,
876 			rcu_dereference(clnt->cl_xprt)->servername);
877 	if (clnt->cl_parent != clnt)
878 		parent = clnt->cl_parent;
879 	rpc_clnt_debugfs_unregister(clnt);
880 	rpc_clnt_remove_pipedir(clnt);
881 	rpc_unregister_client(clnt);
882 	rpc_free_iostats(clnt->cl_metrics);
883 	clnt->cl_metrics = NULL;
884 	xprt_put(rcu_dereference_raw(clnt->cl_xprt));
885 	xprt_iter_destroy(&clnt->cl_xpi);
886 	rpciod_down();
887 	rpc_free_clid(clnt);
888 	kfree(clnt);
889 	return parent;
890 }
891 
892 /*
893  * Free an RPC client
894  */
895 static struct rpc_clnt *
896 rpc_free_auth(struct rpc_clnt *clnt)
897 {
898 	if (clnt->cl_auth == NULL)
899 		return rpc_free_client(clnt);
900 
901 	/*
902 	 * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
903 	 *       release remaining GSS contexts. This mechanism ensures
904 	 *       that it can do so safely.
905 	 */
906 	atomic_inc(&clnt->cl_count);
907 	rpcauth_release(clnt->cl_auth);
908 	clnt->cl_auth = NULL;
909 	if (atomic_dec_and_test(&clnt->cl_count))
910 		return rpc_free_client(clnt);
911 	return NULL;
912 }
913 
914 /*
915  * Release reference to the RPC client
916  */
917 void
918 rpc_release_client(struct rpc_clnt *clnt)
919 {
920 	dprintk("RPC:       rpc_release_client(%p)\n", clnt);
921 
922 	do {
923 		if (list_empty(&clnt->cl_tasks))
924 			wake_up(&destroy_wait);
925 		if (!atomic_dec_and_test(&clnt->cl_count))
926 			break;
927 		clnt = rpc_free_auth(clnt);
928 	} while (clnt != NULL);
929 }
930 EXPORT_SYMBOL_GPL(rpc_release_client);
931 
932 /**
933  * rpc_bind_new_program - bind a new RPC program to an existing client
934  * @old: old rpc_client
935  * @program: rpc program to set
936  * @vers: rpc program version
937  *
938  * Clones the rpc client and sets up a new RPC program. This is mainly
939  * of use for enabling different RPC programs to share the same transport.
940  * The Sun NFSv2/v3 ACL protocol can do this.
941  */
942 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
943 				      const struct rpc_program *program,
944 				      u32 vers)
945 {
946 	struct rpc_create_args args = {
947 		.program	= program,
948 		.prognumber	= program->number,
949 		.version	= vers,
950 		.authflavor	= old->cl_auth->au_flavor,
951 	};
952 	struct rpc_clnt *clnt;
953 	int err;
954 
955 	clnt = __rpc_clone_client(&args, old);
956 	if (IS_ERR(clnt))
957 		goto out;
958 	err = rpc_ping(clnt);
959 	if (err != 0) {
960 		rpc_shutdown_client(clnt);
961 		clnt = ERR_PTR(err);
962 	}
963 out:
964 	return clnt;
965 }
966 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
967 
968 void rpc_task_release_client(struct rpc_task *task)
969 {
970 	struct rpc_clnt *clnt = task->tk_client;
971 	struct rpc_xprt *xprt = task->tk_xprt;
972 
973 	if (clnt != NULL) {
974 		/* Remove from client task list */
975 		spin_lock(&clnt->cl_lock);
976 		list_del(&task->tk_task);
977 		spin_unlock(&clnt->cl_lock);
978 		task->tk_client = NULL;
979 
980 		rpc_release_client(clnt);
981 	}
982 
983 	if (xprt != NULL) {
984 		task->tk_xprt = NULL;
985 
986 		xprt_put(xprt);
987 	}
988 }
989 
990 static
991 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
992 {
993 
994 	if (clnt != NULL) {
995 		if (task->tk_xprt == NULL)
996 			task->tk_xprt = xprt_iter_get_next(&clnt->cl_xpi);
997 		task->tk_client = clnt;
998 		atomic_inc(&clnt->cl_count);
999 		if (clnt->cl_softrtry)
1000 			task->tk_flags |= RPC_TASK_SOFT;
1001 		if (clnt->cl_noretranstimeo)
1002 			task->tk_flags |= RPC_TASK_NO_RETRANS_TIMEOUT;
1003 		if (atomic_read(&clnt->cl_swapper))
1004 			task->tk_flags |= RPC_TASK_SWAPPER;
1005 		/* Add to the client's list of all tasks */
1006 		spin_lock(&clnt->cl_lock);
1007 		list_add_tail(&task->tk_task, &clnt->cl_tasks);
1008 		spin_unlock(&clnt->cl_lock);
1009 	}
1010 }
1011 
1012 static void
1013 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
1014 {
1015 	if (msg != NULL) {
1016 		task->tk_msg.rpc_proc = msg->rpc_proc;
1017 		task->tk_msg.rpc_argp = msg->rpc_argp;
1018 		task->tk_msg.rpc_resp = msg->rpc_resp;
1019 		if (msg->rpc_cred != NULL)
1020 			task->tk_msg.rpc_cred = get_rpccred(msg->rpc_cred);
1021 	}
1022 }
1023 
1024 /*
1025  * Default callback for async RPC calls
1026  */
1027 static void
1028 rpc_default_callback(struct rpc_task *task, void *data)
1029 {
1030 }
1031 
1032 static const struct rpc_call_ops rpc_default_ops = {
1033 	.rpc_call_done = rpc_default_callback,
1034 };
1035 
1036 /**
1037  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
1038  * @task_setup_data: pointer to task initialisation data
1039  */
1040 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
1041 {
1042 	struct rpc_task *task;
1043 
1044 	task = rpc_new_task(task_setup_data);
1045 
1046 	rpc_task_set_client(task, task_setup_data->rpc_client);
1047 	rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
1048 
1049 	if (task->tk_action == NULL)
1050 		rpc_call_start(task);
1051 
1052 	atomic_inc(&task->tk_count);
1053 	rpc_execute(task);
1054 	return task;
1055 }
1056 EXPORT_SYMBOL_GPL(rpc_run_task);
1057 
1058 /**
1059  * rpc_call_sync - Perform a synchronous RPC call
1060  * @clnt: pointer to RPC client
1061  * @msg: RPC call parameters
1062  * @flags: RPC call flags
1063  */
1064 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
1065 {
1066 	struct rpc_task	*task;
1067 	struct rpc_task_setup task_setup_data = {
1068 		.rpc_client = clnt,
1069 		.rpc_message = msg,
1070 		.callback_ops = &rpc_default_ops,
1071 		.flags = flags,
1072 	};
1073 	int status;
1074 
1075 	WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
1076 	if (flags & RPC_TASK_ASYNC) {
1077 		rpc_release_calldata(task_setup_data.callback_ops,
1078 			task_setup_data.callback_data);
1079 		return -EINVAL;
1080 	}
1081 
1082 	task = rpc_run_task(&task_setup_data);
1083 	if (IS_ERR(task))
1084 		return PTR_ERR(task);
1085 	status = task->tk_status;
1086 	rpc_put_task(task);
1087 	return status;
1088 }
1089 EXPORT_SYMBOL_GPL(rpc_call_sync);
1090 
1091 /**
1092  * rpc_call_async - Perform an asynchronous RPC call
1093  * @clnt: pointer to RPC client
1094  * @msg: RPC call parameters
1095  * @flags: RPC call flags
1096  * @tk_ops: RPC call ops
1097  * @data: user call data
1098  */
1099 int
1100 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
1101 	       const struct rpc_call_ops *tk_ops, void *data)
1102 {
1103 	struct rpc_task	*task;
1104 	struct rpc_task_setup task_setup_data = {
1105 		.rpc_client = clnt,
1106 		.rpc_message = msg,
1107 		.callback_ops = tk_ops,
1108 		.callback_data = data,
1109 		.flags = flags|RPC_TASK_ASYNC,
1110 	};
1111 
1112 	task = rpc_run_task(&task_setup_data);
1113 	if (IS_ERR(task))
1114 		return PTR_ERR(task);
1115 	rpc_put_task(task);
1116 	return 0;
1117 }
1118 EXPORT_SYMBOL_GPL(rpc_call_async);
1119 
1120 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1121 /**
1122  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
1123  * rpc_execute against it
1124  * @req: RPC request
1125  */
1126 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req)
1127 {
1128 	struct rpc_task *task;
1129 	struct xdr_buf *xbufp = &req->rq_snd_buf;
1130 	struct rpc_task_setup task_setup_data = {
1131 		.callback_ops = &rpc_default_ops,
1132 		.flags = RPC_TASK_SOFTCONN,
1133 	};
1134 
1135 	dprintk("RPC: rpc_run_bc_task req= %p\n", req);
1136 	/*
1137 	 * Create an rpc_task to send the data
1138 	 */
1139 	task = rpc_new_task(&task_setup_data);
1140 	task->tk_rqstp = req;
1141 
1142 	/*
1143 	 * Set up the xdr_buf length.
1144 	 * This also indicates that the buffer is XDR encoded already.
1145 	 */
1146 	xbufp->len = xbufp->head[0].iov_len + xbufp->page_len +
1147 			xbufp->tail[0].iov_len;
1148 
1149 	task->tk_action = call_bc_transmit;
1150 	atomic_inc(&task->tk_count);
1151 	WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
1152 	rpc_execute(task);
1153 
1154 	dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
1155 	return task;
1156 }
1157 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1158 
1159 void
1160 rpc_call_start(struct rpc_task *task)
1161 {
1162 	task->tk_action = call_start;
1163 }
1164 EXPORT_SYMBOL_GPL(rpc_call_start);
1165 
1166 /**
1167  * rpc_peeraddr - extract remote peer address from clnt's xprt
1168  * @clnt: RPC client structure
1169  * @buf: target buffer
1170  * @bufsize: length of target buffer
1171  *
1172  * Returns the number of bytes that are actually in the stored address.
1173  */
1174 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
1175 {
1176 	size_t bytes;
1177 	struct rpc_xprt *xprt;
1178 
1179 	rcu_read_lock();
1180 	xprt = rcu_dereference(clnt->cl_xprt);
1181 
1182 	bytes = xprt->addrlen;
1183 	if (bytes > bufsize)
1184 		bytes = bufsize;
1185 	memcpy(buf, &xprt->addr, bytes);
1186 	rcu_read_unlock();
1187 
1188 	return bytes;
1189 }
1190 EXPORT_SYMBOL_GPL(rpc_peeraddr);
1191 
1192 /**
1193  * rpc_peeraddr2str - return remote peer address in printable format
1194  * @clnt: RPC client structure
1195  * @format: address format
1196  *
1197  * NB: the lifetime of the memory referenced by the returned pointer is
1198  * the same as the rpc_xprt itself.  As long as the caller uses this
1199  * pointer, it must hold the RCU read lock.
1200  */
1201 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
1202 			     enum rpc_display_format_t format)
1203 {
1204 	struct rpc_xprt *xprt;
1205 
1206 	xprt = rcu_dereference(clnt->cl_xprt);
1207 
1208 	if (xprt->address_strings[format] != NULL)
1209 		return xprt->address_strings[format];
1210 	else
1211 		return "unprintable";
1212 }
1213 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
1214 
1215 static const struct sockaddr_in rpc_inaddr_loopback = {
1216 	.sin_family		= AF_INET,
1217 	.sin_addr.s_addr	= htonl(INADDR_ANY),
1218 };
1219 
1220 static const struct sockaddr_in6 rpc_in6addr_loopback = {
1221 	.sin6_family		= AF_INET6,
1222 	.sin6_addr		= IN6ADDR_ANY_INIT,
1223 };
1224 
1225 /*
1226  * Try a getsockname() on a connected datagram socket.  Using a
1227  * connected datagram socket prevents leaving a socket in TIME_WAIT.
1228  * This conserves the ephemeral port number space.
1229  *
1230  * Returns zero and fills in "buf" if successful; otherwise, a
1231  * negative errno is returned.
1232  */
1233 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1234 			struct sockaddr *buf, int buflen)
1235 {
1236 	struct socket *sock;
1237 	int err;
1238 
1239 	err = __sock_create(net, sap->sa_family,
1240 				SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1241 	if (err < 0) {
1242 		dprintk("RPC:       can't create UDP socket (%d)\n", err);
1243 		goto out;
1244 	}
1245 
1246 	switch (sap->sa_family) {
1247 	case AF_INET:
1248 		err = kernel_bind(sock,
1249 				(struct sockaddr *)&rpc_inaddr_loopback,
1250 				sizeof(rpc_inaddr_loopback));
1251 		break;
1252 	case AF_INET6:
1253 		err = kernel_bind(sock,
1254 				(struct sockaddr *)&rpc_in6addr_loopback,
1255 				sizeof(rpc_in6addr_loopback));
1256 		break;
1257 	default:
1258 		err = -EAFNOSUPPORT;
1259 		goto out;
1260 	}
1261 	if (err < 0) {
1262 		dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1263 		goto out_release;
1264 	}
1265 
1266 	err = kernel_connect(sock, sap, salen, 0);
1267 	if (err < 0) {
1268 		dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1269 		goto out_release;
1270 	}
1271 
1272 	err = kernel_getsockname(sock, buf, &buflen);
1273 	if (err < 0) {
1274 		dprintk("RPC:       getsockname failed (%d)\n", err);
1275 		goto out_release;
1276 	}
1277 
1278 	err = 0;
1279 	if (buf->sa_family == AF_INET6) {
1280 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1281 		sin6->sin6_scope_id = 0;
1282 	}
1283 	dprintk("RPC:       %s succeeded\n", __func__);
1284 
1285 out_release:
1286 	sock_release(sock);
1287 out:
1288 	return err;
1289 }
1290 
1291 /*
1292  * Scraping a connected socket failed, so we don't have a useable
1293  * local address.  Fallback: generate an address that will prevent
1294  * the server from calling us back.
1295  *
1296  * Returns zero and fills in "buf" if successful; otherwise, a
1297  * negative errno is returned.
1298  */
1299 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1300 {
1301 	switch (family) {
1302 	case AF_INET:
1303 		if (buflen < sizeof(rpc_inaddr_loopback))
1304 			return -EINVAL;
1305 		memcpy(buf, &rpc_inaddr_loopback,
1306 				sizeof(rpc_inaddr_loopback));
1307 		break;
1308 	case AF_INET6:
1309 		if (buflen < sizeof(rpc_in6addr_loopback))
1310 			return -EINVAL;
1311 		memcpy(buf, &rpc_in6addr_loopback,
1312 				sizeof(rpc_in6addr_loopback));
1313 		break;
1314 	default:
1315 		dprintk("RPC:       %s: address family not supported\n",
1316 			__func__);
1317 		return -EAFNOSUPPORT;
1318 	}
1319 	dprintk("RPC:       %s: succeeded\n", __func__);
1320 	return 0;
1321 }
1322 
1323 /**
1324  * rpc_localaddr - discover local endpoint address for an RPC client
1325  * @clnt: RPC client structure
1326  * @buf: target buffer
1327  * @buflen: size of target buffer, in bytes
1328  *
1329  * Returns zero and fills in "buf" and "buflen" if successful;
1330  * otherwise, a negative errno is returned.
1331  *
1332  * This works even if the underlying transport is not currently connected,
1333  * or if the upper layer never previously provided a source address.
1334  *
1335  * The result of this function call is transient: multiple calls in
1336  * succession may give different results, depending on how local
1337  * networking configuration changes over time.
1338  */
1339 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1340 {
1341 	struct sockaddr_storage address;
1342 	struct sockaddr *sap = (struct sockaddr *)&address;
1343 	struct rpc_xprt *xprt;
1344 	struct net *net;
1345 	size_t salen;
1346 	int err;
1347 
1348 	rcu_read_lock();
1349 	xprt = rcu_dereference(clnt->cl_xprt);
1350 	salen = xprt->addrlen;
1351 	memcpy(sap, &xprt->addr, salen);
1352 	net = get_net(xprt->xprt_net);
1353 	rcu_read_unlock();
1354 
1355 	rpc_set_port(sap, 0);
1356 	err = rpc_sockname(net, sap, salen, buf, buflen);
1357 	put_net(net);
1358 	if (err != 0)
1359 		/* Couldn't discover local address, return ANYADDR */
1360 		return rpc_anyaddr(sap->sa_family, buf, buflen);
1361 	return 0;
1362 }
1363 EXPORT_SYMBOL_GPL(rpc_localaddr);
1364 
1365 void
1366 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1367 {
1368 	struct rpc_xprt *xprt;
1369 
1370 	rcu_read_lock();
1371 	xprt = rcu_dereference(clnt->cl_xprt);
1372 	if (xprt->ops->set_buffer_size)
1373 		xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1374 	rcu_read_unlock();
1375 }
1376 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1377 
1378 /**
1379  * rpc_protocol - Get transport protocol number for an RPC client
1380  * @clnt: RPC client to query
1381  *
1382  */
1383 int rpc_protocol(struct rpc_clnt *clnt)
1384 {
1385 	int protocol;
1386 
1387 	rcu_read_lock();
1388 	protocol = rcu_dereference(clnt->cl_xprt)->prot;
1389 	rcu_read_unlock();
1390 	return protocol;
1391 }
1392 EXPORT_SYMBOL_GPL(rpc_protocol);
1393 
1394 /**
1395  * rpc_net_ns - Get the network namespace for this RPC client
1396  * @clnt: RPC client to query
1397  *
1398  */
1399 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1400 {
1401 	struct net *ret;
1402 
1403 	rcu_read_lock();
1404 	ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1405 	rcu_read_unlock();
1406 	return ret;
1407 }
1408 EXPORT_SYMBOL_GPL(rpc_net_ns);
1409 
1410 /**
1411  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1412  * @clnt: RPC client to query
1413  *
1414  * For stream transports, this is one RPC record fragment (see RFC
1415  * 1831), as we don't support multi-record requests yet.  For datagram
1416  * transports, this is the size of an IP packet minus the IP, UDP, and
1417  * RPC header sizes.
1418  */
1419 size_t rpc_max_payload(struct rpc_clnt *clnt)
1420 {
1421 	size_t ret;
1422 
1423 	rcu_read_lock();
1424 	ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1425 	rcu_read_unlock();
1426 	return ret;
1427 }
1428 EXPORT_SYMBOL_GPL(rpc_max_payload);
1429 
1430 /**
1431  * rpc_max_bc_payload - Get maximum backchannel payload size, in bytes
1432  * @clnt: RPC client to query
1433  */
1434 size_t rpc_max_bc_payload(struct rpc_clnt *clnt)
1435 {
1436 	struct rpc_xprt *xprt;
1437 	size_t ret;
1438 
1439 	rcu_read_lock();
1440 	xprt = rcu_dereference(clnt->cl_xprt);
1441 	ret = xprt->ops->bc_maxpayload(xprt);
1442 	rcu_read_unlock();
1443 	return ret;
1444 }
1445 EXPORT_SYMBOL_GPL(rpc_max_bc_payload);
1446 
1447 /**
1448  * rpc_force_rebind - force transport to check that remote port is unchanged
1449  * @clnt: client to rebind
1450  *
1451  */
1452 void rpc_force_rebind(struct rpc_clnt *clnt)
1453 {
1454 	if (clnt->cl_autobind) {
1455 		rcu_read_lock();
1456 		xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1457 		rcu_read_unlock();
1458 	}
1459 }
1460 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1461 
1462 /*
1463  * Restart an (async) RPC call from the call_prepare state.
1464  * Usually called from within the exit handler.
1465  */
1466 int
1467 rpc_restart_call_prepare(struct rpc_task *task)
1468 {
1469 	if (RPC_ASSASSINATED(task))
1470 		return 0;
1471 	task->tk_action = call_start;
1472 	task->tk_status = 0;
1473 	if (task->tk_ops->rpc_call_prepare != NULL)
1474 		task->tk_action = rpc_prepare_task;
1475 	return 1;
1476 }
1477 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1478 
1479 /*
1480  * Restart an (async) RPC call. Usually called from within the
1481  * exit handler.
1482  */
1483 int
1484 rpc_restart_call(struct rpc_task *task)
1485 {
1486 	if (RPC_ASSASSINATED(task))
1487 		return 0;
1488 	task->tk_action = call_start;
1489 	task->tk_status = 0;
1490 	return 1;
1491 }
1492 EXPORT_SYMBOL_GPL(rpc_restart_call);
1493 
1494 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
1495 const char
1496 *rpc_proc_name(const struct rpc_task *task)
1497 {
1498 	const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1499 
1500 	if (proc) {
1501 		if (proc->p_name)
1502 			return proc->p_name;
1503 		else
1504 			return "NULL";
1505 	} else
1506 		return "no proc";
1507 }
1508 #endif
1509 
1510 /*
1511  * 0.  Initial state
1512  *
1513  *     Other FSM states can be visited zero or more times, but
1514  *     this state is visited exactly once for each RPC.
1515  */
1516 static void
1517 call_start(struct rpc_task *task)
1518 {
1519 	struct rpc_clnt	*clnt = task->tk_client;
1520 	int idx = task->tk_msg.rpc_proc->p_statidx;
1521 
1522 	dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1523 			clnt->cl_program->name, clnt->cl_vers,
1524 			rpc_proc_name(task),
1525 			(RPC_IS_ASYNC(task) ? "async" : "sync"));
1526 
1527 	/* Increment call count (version might not be valid for ping) */
1528 	if (clnt->cl_program->version[clnt->cl_vers])
1529 		clnt->cl_program->version[clnt->cl_vers]->counts[idx]++;
1530 	clnt->cl_stats->rpccnt++;
1531 	task->tk_action = call_reserve;
1532 }
1533 
1534 /*
1535  * 1.	Reserve an RPC call slot
1536  */
1537 static void
1538 call_reserve(struct rpc_task *task)
1539 {
1540 	dprint_status(task);
1541 
1542 	task->tk_status  = 0;
1543 	task->tk_action  = call_reserveresult;
1544 	xprt_reserve(task);
1545 }
1546 
1547 static void call_retry_reserve(struct rpc_task *task);
1548 
1549 /*
1550  * 1b.	Grok the result of xprt_reserve()
1551  */
1552 static void
1553 call_reserveresult(struct rpc_task *task)
1554 {
1555 	int status = task->tk_status;
1556 
1557 	dprint_status(task);
1558 
1559 	/*
1560 	 * After a call to xprt_reserve(), we must have either
1561 	 * a request slot or else an error status.
1562 	 */
1563 	task->tk_status = 0;
1564 	if (status >= 0) {
1565 		if (task->tk_rqstp) {
1566 			task->tk_action = call_refresh;
1567 			return;
1568 		}
1569 
1570 		printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1571 				__func__, status);
1572 		rpc_exit(task, -EIO);
1573 		return;
1574 	}
1575 
1576 	/*
1577 	 * Even though there was an error, we may have acquired
1578 	 * a request slot somehow.  Make sure not to leak it.
1579 	 */
1580 	if (task->tk_rqstp) {
1581 		printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1582 				__func__, status);
1583 		xprt_release(task);
1584 	}
1585 
1586 	switch (status) {
1587 	case -ENOMEM:
1588 		rpc_delay(task, HZ >> 2);
1589 	case -EAGAIN:	/* woken up; retry */
1590 		task->tk_action = call_retry_reserve;
1591 		return;
1592 	case -EIO:	/* probably a shutdown */
1593 		break;
1594 	default:
1595 		printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1596 				__func__, status);
1597 		break;
1598 	}
1599 	rpc_exit(task, status);
1600 }
1601 
1602 /*
1603  * 1c.	Retry reserving an RPC call slot
1604  */
1605 static void
1606 call_retry_reserve(struct rpc_task *task)
1607 {
1608 	dprint_status(task);
1609 
1610 	task->tk_status  = 0;
1611 	task->tk_action  = call_reserveresult;
1612 	xprt_retry_reserve(task);
1613 }
1614 
1615 /*
1616  * 2.	Bind and/or refresh the credentials
1617  */
1618 static void
1619 call_refresh(struct rpc_task *task)
1620 {
1621 	dprint_status(task);
1622 
1623 	task->tk_action = call_refreshresult;
1624 	task->tk_status = 0;
1625 	task->tk_client->cl_stats->rpcauthrefresh++;
1626 	rpcauth_refreshcred(task);
1627 }
1628 
1629 /*
1630  * 2a.	Process the results of a credential refresh
1631  */
1632 static void
1633 call_refreshresult(struct rpc_task *task)
1634 {
1635 	int status = task->tk_status;
1636 
1637 	dprint_status(task);
1638 
1639 	task->tk_status = 0;
1640 	task->tk_action = call_refresh;
1641 	switch (status) {
1642 	case 0:
1643 		if (rpcauth_uptodatecred(task)) {
1644 			task->tk_action = call_allocate;
1645 			return;
1646 		}
1647 		/* Use rate-limiting and a max number of retries if refresh
1648 		 * had status 0 but failed to update the cred.
1649 		 */
1650 	case -ETIMEDOUT:
1651 		rpc_delay(task, 3*HZ);
1652 	case -EAGAIN:
1653 		status = -EACCES;
1654 	case -EKEYEXPIRED:
1655 		if (!task->tk_cred_retry)
1656 			break;
1657 		task->tk_cred_retry--;
1658 		dprintk("RPC: %5u %s: retry refresh creds\n",
1659 				task->tk_pid, __func__);
1660 		return;
1661 	}
1662 	dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1663 				task->tk_pid, __func__, status);
1664 	rpc_exit(task, status);
1665 }
1666 
1667 /*
1668  * 2b.	Allocate the buffer. For details, see sched.c:rpc_malloc.
1669  *	(Note: buffer memory is freed in xprt_release).
1670  */
1671 static void
1672 call_allocate(struct rpc_task *task)
1673 {
1674 	unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1675 	struct rpc_rqst *req = task->tk_rqstp;
1676 	struct rpc_xprt *xprt = req->rq_xprt;
1677 	const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1678 	int status;
1679 
1680 	dprint_status(task);
1681 
1682 	task->tk_status = 0;
1683 	task->tk_action = call_bind;
1684 
1685 	if (req->rq_buffer)
1686 		return;
1687 
1688 	if (proc->p_proc != 0) {
1689 		BUG_ON(proc->p_arglen == 0);
1690 		if (proc->p_decode != NULL)
1691 			BUG_ON(proc->p_replen == 0);
1692 	}
1693 
1694 	/*
1695 	 * Calculate the size (in quads) of the RPC call
1696 	 * and reply headers, and convert both values
1697 	 * to byte sizes.
1698 	 */
1699 	req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1700 	req->rq_callsize <<= 2;
1701 	req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1702 	req->rq_rcvsize <<= 2;
1703 
1704 	status = xprt->ops->buf_alloc(task);
1705 	xprt_inject_disconnect(xprt);
1706 	if (status == 0)
1707 		return;
1708 	if (status != -ENOMEM) {
1709 		rpc_exit(task, status);
1710 		return;
1711 	}
1712 
1713 	dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1714 
1715 	if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1716 		task->tk_action = call_allocate;
1717 		rpc_delay(task, HZ>>4);
1718 		return;
1719 	}
1720 
1721 	rpc_exit(task, -ERESTARTSYS);
1722 }
1723 
1724 static inline int
1725 rpc_task_need_encode(struct rpc_task *task)
1726 {
1727 	return task->tk_rqstp->rq_snd_buf.len == 0;
1728 }
1729 
1730 static inline void
1731 rpc_task_force_reencode(struct rpc_task *task)
1732 {
1733 	task->tk_rqstp->rq_snd_buf.len = 0;
1734 	task->tk_rqstp->rq_bytes_sent = 0;
1735 }
1736 
1737 /*
1738  * 3.	Encode arguments of an RPC call
1739  */
1740 static void
1741 rpc_xdr_encode(struct rpc_task *task)
1742 {
1743 	struct rpc_rqst	*req = task->tk_rqstp;
1744 	kxdreproc_t	encode;
1745 	__be32		*p;
1746 
1747 	dprint_status(task);
1748 
1749 	xdr_buf_init(&req->rq_snd_buf,
1750 		     req->rq_buffer,
1751 		     req->rq_callsize);
1752 	xdr_buf_init(&req->rq_rcv_buf,
1753 		     req->rq_rbuffer,
1754 		     req->rq_rcvsize);
1755 
1756 	p = rpc_encode_header(task);
1757 	if (p == NULL) {
1758 		printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1759 		rpc_exit(task, -EIO);
1760 		return;
1761 	}
1762 
1763 	encode = task->tk_msg.rpc_proc->p_encode;
1764 	if (encode == NULL)
1765 		return;
1766 
1767 	task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1768 			task->tk_msg.rpc_argp);
1769 }
1770 
1771 /*
1772  * 4.	Get the server port number if not yet set
1773  */
1774 static void
1775 call_bind(struct rpc_task *task)
1776 {
1777 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1778 
1779 	dprint_status(task);
1780 
1781 	task->tk_action = call_connect;
1782 	if (!xprt_bound(xprt)) {
1783 		task->tk_action = call_bind_status;
1784 		task->tk_timeout = xprt->bind_timeout;
1785 		xprt->ops->rpcbind(task);
1786 	}
1787 }
1788 
1789 /*
1790  * 4a.	Sort out bind result
1791  */
1792 static void
1793 call_bind_status(struct rpc_task *task)
1794 {
1795 	int status = -EIO;
1796 
1797 	if (task->tk_status >= 0) {
1798 		dprint_status(task);
1799 		task->tk_status = 0;
1800 		task->tk_action = call_connect;
1801 		return;
1802 	}
1803 
1804 	trace_rpc_bind_status(task);
1805 	switch (task->tk_status) {
1806 	case -ENOMEM:
1807 		dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1808 		rpc_delay(task, HZ >> 2);
1809 		goto retry_timeout;
1810 	case -EACCES:
1811 		dprintk("RPC: %5u remote rpcbind: RPC program/version "
1812 				"unavailable\n", task->tk_pid);
1813 		/* fail immediately if this is an RPC ping */
1814 		if (task->tk_msg.rpc_proc->p_proc == 0) {
1815 			status = -EOPNOTSUPP;
1816 			break;
1817 		}
1818 		if (task->tk_rebind_retry == 0)
1819 			break;
1820 		task->tk_rebind_retry--;
1821 		rpc_delay(task, 3*HZ);
1822 		goto retry_timeout;
1823 	case -ETIMEDOUT:
1824 		dprintk("RPC: %5u rpcbind request timed out\n",
1825 				task->tk_pid);
1826 		goto retry_timeout;
1827 	case -EPFNOSUPPORT:
1828 		/* server doesn't support any rpcbind version we know of */
1829 		dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1830 				task->tk_pid);
1831 		break;
1832 	case -EPROTONOSUPPORT:
1833 		dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1834 				task->tk_pid);
1835 		goto retry_timeout;
1836 	case -ECONNREFUSED:		/* connection problems */
1837 	case -ECONNRESET:
1838 	case -ECONNABORTED:
1839 	case -ENOTCONN:
1840 	case -EHOSTDOWN:
1841 	case -EHOSTUNREACH:
1842 	case -ENETUNREACH:
1843 	case -ENOBUFS:
1844 	case -EPIPE:
1845 		dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1846 				task->tk_pid, task->tk_status);
1847 		if (!RPC_IS_SOFTCONN(task)) {
1848 			rpc_delay(task, 5*HZ);
1849 			goto retry_timeout;
1850 		}
1851 		status = task->tk_status;
1852 		break;
1853 	default:
1854 		dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1855 				task->tk_pid, -task->tk_status);
1856 	}
1857 
1858 	rpc_exit(task, status);
1859 	return;
1860 
1861 retry_timeout:
1862 	task->tk_status = 0;
1863 	task->tk_action = call_timeout;
1864 }
1865 
1866 /*
1867  * 4b.	Connect to the RPC server
1868  */
1869 static void
1870 call_connect(struct rpc_task *task)
1871 {
1872 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1873 
1874 	dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1875 			task->tk_pid, xprt,
1876 			(xprt_connected(xprt) ? "is" : "is not"));
1877 
1878 	task->tk_action = call_transmit;
1879 	if (!xprt_connected(xprt)) {
1880 		task->tk_action = call_connect_status;
1881 		if (task->tk_status < 0)
1882 			return;
1883 		if (task->tk_flags & RPC_TASK_NOCONNECT) {
1884 			rpc_exit(task, -ENOTCONN);
1885 			return;
1886 		}
1887 		xprt_connect(task);
1888 	}
1889 }
1890 
1891 /*
1892  * 4c.	Sort out connect result
1893  */
1894 static void
1895 call_connect_status(struct rpc_task *task)
1896 {
1897 	struct rpc_clnt *clnt = task->tk_client;
1898 	int status = task->tk_status;
1899 
1900 	dprint_status(task);
1901 
1902 	trace_rpc_connect_status(task, status);
1903 	task->tk_status = 0;
1904 	switch (status) {
1905 	case -ECONNREFUSED:
1906 		/* A positive refusal suggests a rebind is needed. */
1907 		if (RPC_IS_SOFTCONN(task))
1908 			break;
1909 		if (clnt->cl_autobind) {
1910 			rpc_force_rebind(clnt);
1911 			task->tk_action = call_bind;
1912 			return;
1913 		}
1914 	case -ECONNRESET:
1915 	case -ECONNABORTED:
1916 	case -ENETUNREACH:
1917 	case -EHOSTUNREACH:
1918 	case -EADDRINUSE:
1919 	case -ENOBUFS:
1920 	case -EPIPE:
1921 		xprt_conditional_disconnect(task->tk_rqstp->rq_xprt,
1922 					    task->tk_rqstp->rq_connect_cookie);
1923 		if (RPC_IS_SOFTCONN(task))
1924 			break;
1925 		/* retry with existing socket, after a delay */
1926 		rpc_delay(task, 3*HZ);
1927 	case -EAGAIN:
1928 		/* Check for timeouts before looping back to call_bind */
1929 	case -ETIMEDOUT:
1930 		task->tk_action = call_timeout;
1931 		return;
1932 	case 0:
1933 		clnt->cl_stats->netreconn++;
1934 		task->tk_action = call_transmit;
1935 		return;
1936 	}
1937 	rpc_exit(task, status);
1938 }
1939 
1940 /*
1941  * 5.	Transmit the RPC request, and wait for reply
1942  */
1943 static void
1944 call_transmit(struct rpc_task *task)
1945 {
1946 	int is_retrans = RPC_WAS_SENT(task);
1947 
1948 	dprint_status(task);
1949 
1950 	task->tk_action = call_status;
1951 	if (task->tk_status < 0)
1952 		return;
1953 	if (!xprt_prepare_transmit(task))
1954 		return;
1955 	task->tk_action = call_transmit_status;
1956 	/* Encode here so that rpcsec_gss can use correct sequence number. */
1957 	if (rpc_task_need_encode(task)) {
1958 		rpc_xdr_encode(task);
1959 		/* Did the encode result in an error condition? */
1960 		if (task->tk_status != 0) {
1961 			/* Was the error nonfatal? */
1962 			if (task->tk_status == -EAGAIN)
1963 				rpc_delay(task, HZ >> 4);
1964 			else
1965 				rpc_exit(task, task->tk_status);
1966 			return;
1967 		}
1968 	}
1969 	xprt_transmit(task);
1970 	if (task->tk_status < 0)
1971 		return;
1972 	if (is_retrans)
1973 		task->tk_client->cl_stats->rpcretrans++;
1974 	/*
1975 	 * On success, ensure that we call xprt_end_transmit() before sleeping
1976 	 * in order to allow access to the socket to other RPC requests.
1977 	 */
1978 	call_transmit_status(task);
1979 	if (rpc_reply_expected(task))
1980 		return;
1981 	task->tk_action = rpc_exit_task;
1982 	rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1983 }
1984 
1985 /*
1986  * 5a.	Handle cleanup after a transmission
1987  */
1988 static void
1989 call_transmit_status(struct rpc_task *task)
1990 {
1991 	task->tk_action = call_status;
1992 
1993 	/*
1994 	 * Common case: success.  Force the compiler to put this
1995 	 * test first.
1996 	 */
1997 	if (task->tk_status == 0) {
1998 		xprt_end_transmit(task);
1999 		rpc_task_force_reencode(task);
2000 		return;
2001 	}
2002 
2003 	switch (task->tk_status) {
2004 	case -EAGAIN:
2005 	case -ENOBUFS:
2006 		break;
2007 	default:
2008 		dprint_status(task);
2009 		xprt_end_transmit(task);
2010 		rpc_task_force_reencode(task);
2011 		break;
2012 		/*
2013 		 * Special cases: if we've been waiting on the
2014 		 * socket's write_space() callback, or if the
2015 		 * socket just returned a connection error,
2016 		 * then hold onto the transport lock.
2017 		 */
2018 	case -ECONNREFUSED:
2019 	case -EHOSTDOWN:
2020 	case -EHOSTUNREACH:
2021 	case -ENETUNREACH:
2022 	case -EPERM:
2023 		if (RPC_IS_SOFTCONN(task)) {
2024 			xprt_end_transmit(task);
2025 			rpc_exit(task, task->tk_status);
2026 			break;
2027 		}
2028 	case -ECONNRESET:
2029 	case -ECONNABORTED:
2030 	case -EADDRINUSE:
2031 	case -ENOTCONN:
2032 	case -EPIPE:
2033 		rpc_task_force_reencode(task);
2034 	}
2035 }
2036 
2037 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
2038 /*
2039  * 5b.	Send the backchannel RPC reply.  On error, drop the reply.  In
2040  * addition, disconnect on connectivity errors.
2041  */
2042 static void
2043 call_bc_transmit(struct rpc_task *task)
2044 {
2045 	struct rpc_rqst *req = task->tk_rqstp;
2046 
2047 	if (!xprt_prepare_transmit(task))
2048 		goto out_retry;
2049 
2050 	if (task->tk_status < 0) {
2051 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
2052 			"error: %d\n", task->tk_status);
2053 		goto out_done;
2054 	}
2055 	if (req->rq_connect_cookie != req->rq_xprt->connect_cookie)
2056 		req->rq_bytes_sent = 0;
2057 
2058 	xprt_transmit(task);
2059 
2060 	if (task->tk_status == -EAGAIN)
2061 		goto out_nospace;
2062 
2063 	xprt_end_transmit(task);
2064 	dprint_status(task);
2065 	switch (task->tk_status) {
2066 	case 0:
2067 		/* Success */
2068 	case -EHOSTDOWN:
2069 	case -EHOSTUNREACH:
2070 	case -ENETUNREACH:
2071 	case -ECONNRESET:
2072 	case -ECONNREFUSED:
2073 	case -EADDRINUSE:
2074 	case -ENOTCONN:
2075 	case -EPIPE:
2076 		break;
2077 	case -ETIMEDOUT:
2078 		/*
2079 		 * Problem reaching the server.  Disconnect and let the
2080 		 * forechannel reestablish the connection.  The server will
2081 		 * have to retransmit the backchannel request and we'll
2082 		 * reprocess it.  Since these ops are idempotent, there's no
2083 		 * need to cache our reply at this time.
2084 		 */
2085 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
2086 			"error: %d\n", task->tk_status);
2087 		xprt_conditional_disconnect(req->rq_xprt,
2088 			req->rq_connect_cookie);
2089 		break;
2090 	default:
2091 		/*
2092 		 * We were unable to reply and will have to drop the
2093 		 * request.  The server should reconnect and retransmit.
2094 		 */
2095 		WARN_ON_ONCE(task->tk_status == -EAGAIN);
2096 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
2097 			"error: %d\n", task->tk_status);
2098 		break;
2099 	}
2100 	rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
2101 out_done:
2102 	task->tk_action = rpc_exit_task;
2103 	return;
2104 out_nospace:
2105 	req->rq_connect_cookie = req->rq_xprt->connect_cookie;
2106 out_retry:
2107 	task->tk_status = 0;
2108 }
2109 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
2110 
2111 /*
2112  * 6.	Sort out the RPC call status
2113  */
2114 static void
2115 call_status(struct rpc_task *task)
2116 {
2117 	struct rpc_clnt	*clnt = task->tk_client;
2118 	struct rpc_rqst	*req = task->tk_rqstp;
2119 	int		status;
2120 
2121 	if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
2122 		task->tk_status = req->rq_reply_bytes_recvd;
2123 
2124 	dprint_status(task);
2125 
2126 	status = task->tk_status;
2127 	if (status >= 0) {
2128 		task->tk_action = call_decode;
2129 		return;
2130 	}
2131 
2132 	trace_rpc_call_status(task);
2133 	task->tk_status = 0;
2134 	switch(status) {
2135 	case -EHOSTDOWN:
2136 	case -EHOSTUNREACH:
2137 	case -ENETUNREACH:
2138 	case -EPERM:
2139 		if (RPC_IS_SOFTCONN(task)) {
2140 			rpc_exit(task, status);
2141 			break;
2142 		}
2143 		/*
2144 		 * Delay any retries for 3 seconds, then handle as if it
2145 		 * were a timeout.
2146 		 */
2147 		rpc_delay(task, 3*HZ);
2148 	case -ETIMEDOUT:
2149 		task->tk_action = call_timeout;
2150 		break;
2151 	case -ECONNREFUSED:
2152 	case -ECONNRESET:
2153 	case -ECONNABORTED:
2154 		rpc_force_rebind(clnt);
2155 	case -EADDRINUSE:
2156 		rpc_delay(task, 3*HZ);
2157 	case -EPIPE:
2158 	case -ENOTCONN:
2159 		task->tk_action = call_bind;
2160 		break;
2161 	case -ENOBUFS:
2162 		rpc_delay(task, HZ>>2);
2163 	case -EAGAIN:
2164 		task->tk_action = call_transmit;
2165 		break;
2166 	case -EIO:
2167 		/* shutdown or soft timeout */
2168 		rpc_exit(task, status);
2169 		break;
2170 	default:
2171 		if (clnt->cl_chatty)
2172 			printk("%s: RPC call returned error %d\n",
2173 			       clnt->cl_program->name, -status);
2174 		rpc_exit(task, status);
2175 	}
2176 }
2177 
2178 /*
2179  * 6a.	Handle RPC timeout
2180  * 	We do not release the request slot, so we keep using the
2181  *	same XID for all retransmits.
2182  */
2183 static void
2184 call_timeout(struct rpc_task *task)
2185 {
2186 	struct rpc_clnt	*clnt = task->tk_client;
2187 
2188 	if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
2189 		dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
2190 		goto retry;
2191 	}
2192 
2193 	dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
2194 	task->tk_timeouts++;
2195 
2196 	if (RPC_IS_SOFTCONN(task)) {
2197 		rpc_exit(task, -ETIMEDOUT);
2198 		return;
2199 	}
2200 	if (RPC_IS_SOFT(task)) {
2201 		if (clnt->cl_chatty) {
2202 			printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
2203 				clnt->cl_program->name,
2204 				task->tk_xprt->servername);
2205 		}
2206 		if (task->tk_flags & RPC_TASK_TIMEOUT)
2207 			rpc_exit(task, -ETIMEDOUT);
2208 		else
2209 			rpc_exit(task, -EIO);
2210 		return;
2211 	}
2212 
2213 	if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
2214 		task->tk_flags |= RPC_CALL_MAJORSEEN;
2215 		if (clnt->cl_chatty) {
2216 			printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
2217 			clnt->cl_program->name,
2218 			task->tk_xprt->servername);
2219 		}
2220 	}
2221 	rpc_force_rebind(clnt);
2222 	/*
2223 	 * Did our request time out due to an RPCSEC_GSS out-of-sequence
2224 	 * event? RFC2203 requires the server to drop all such requests.
2225 	 */
2226 	rpcauth_invalcred(task);
2227 
2228 retry:
2229 	task->tk_action = call_bind;
2230 	task->tk_status = 0;
2231 }
2232 
2233 /*
2234  * 7.	Decode the RPC reply
2235  */
2236 static void
2237 call_decode(struct rpc_task *task)
2238 {
2239 	struct rpc_clnt	*clnt = task->tk_client;
2240 	struct rpc_rqst	*req = task->tk_rqstp;
2241 	kxdrdproc_t	decode = task->tk_msg.rpc_proc->p_decode;
2242 	__be32		*p;
2243 
2244 	dprint_status(task);
2245 
2246 	if (task->tk_flags & RPC_CALL_MAJORSEEN) {
2247 		if (clnt->cl_chatty) {
2248 			printk(KERN_NOTICE "%s: server %s OK\n",
2249 				clnt->cl_program->name,
2250 				task->tk_xprt->servername);
2251 		}
2252 		task->tk_flags &= ~RPC_CALL_MAJORSEEN;
2253 	}
2254 
2255 	/*
2256 	 * Ensure that we see all writes made by xprt_complete_rqst()
2257 	 * before it changed req->rq_reply_bytes_recvd.
2258 	 */
2259 	smp_rmb();
2260 	req->rq_rcv_buf.len = req->rq_private_buf.len;
2261 
2262 	/* Check that the softirq receive buffer is valid */
2263 	WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
2264 				sizeof(req->rq_rcv_buf)) != 0);
2265 
2266 	if (req->rq_rcv_buf.len < 12) {
2267 		if (!RPC_IS_SOFT(task)) {
2268 			task->tk_action = call_bind;
2269 			goto out_retry;
2270 		}
2271 		dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2272 				clnt->cl_program->name, task->tk_status);
2273 		task->tk_action = call_timeout;
2274 		goto out_retry;
2275 	}
2276 
2277 	p = rpc_verify_header(task);
2278 	if (IS_ERR(p)) {
2279 		if (p == ERR_PTR(-EAGAIN))
2280 			goto out_retry;
2281 		return;
2282 	}
2283 
2284 	task->tk_action = rpc_exit_task;
2285 
2286 	if (decode) {
2287 		task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2288 						      task->tk_msg.rpc_resp);
2289 	}
2290 	dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2291 			task->tk_status);
2292 	return;
2293 out_retry:
2294 	task->tk_status = 0;
2295 	/* Note: rpc_verify_header() may have freed the RPC slot */
2296 	if (task->tk_rqstp == req) {
2297 		req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2298 		if (task->tk_client->cl_discrtry)
2299 			xprt_conditional_disconnect(req->rq_xprt,
2300 					req->rq_connect_cookie);
2301 	}
2302 }
2303 
2304 static __be32 *
2305 rpc_encode_header(struct rpc_task *task)
2306 {
2307 	struct rpc_clnt *clnt = task->tk_client;
2308 	struct rpc_rqst	*req = task->tk_rqstp;
2309 	__be32		*p = req->rq_svec[0].iov_base;
2310 
2311 	/* FIXME: check buffer size? */
2312 
2313 	p = xprt_skip_transport_header(req->rq_xprt, p);
2314 	*p++ = req->rq_xid;		/* XID */
2315 	*p++ = htonl(RPC_CALL);		/* CALL */
2316 	*p++ = htonl(RPC_VERSION);	/* RPC version */
2317 	*p++ = htonl(clnt->cl_prog);	/* program number */
2318 	*p++ = htonl(clnt->cl_vers);	/* program version */
2319 	*p++ = htonl(task->tk_msg.rpc_proc->p_proc);	/* procedure */
2320 	p = rpcauth_marshcred(task, p);
2321 	req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2322 	return p;
2323 }
2324 
2325 static __be32 *
2326 rpc_verify_header(struct rpc_task *task)
2327 {
2328 	struct rpc_clnt *clnt = task->tk_client;
2329 	struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2330 	int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2331 	__be32	*p = iov->iov_base;
2332 	u32 n;
2333 	int error = -EACCES;
2334 
2335 	if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2336 		/* RFC-1014 says that the representation of XDR data must be a
2337 		 * multiple of four bytes
2338 		 * - if it isn't pointer subtraction in the NFS client may give
2339 		 *   undefined results
2340 		 */
2341 		dprintk("RPC: %5u %s: XDR representation not a multiple of"
2342 		       " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2343 		       task->tk_rqstp->rq_rcv_buf.len);
2344 		error = -EIO;
2345 		goto out_err;
2346 	}
2347 	if ((len -= 3) < 0)
2348 		goto out_overflow;
2349 
2350 	p += 1; /* skip XID */
2351 	if ((n = ntohl(*p++)) != RPC_REPLY) {
2352 		dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2353 			task->tk_pid, __func__, n);
2354 		error = -EIO;
2355 		goto out_garbage;
2356 	}
2357 
2358 	if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2359 		if (--len < 0)
2360 			goto out_overflow;
2361 		switch ((n = ntohl(*p++))) {
2362 		case RPC_AUTH_ERROR:
2363 			break;
2364 		case RPC_MISMATCH:
2365 			dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2366 				task->tk_pid, __func__);
2367 			error = -EPROTONOSUPPORT;
2368 			goto out_err;
2369 		default:
2370 			dprintk("RPC: %5u %s: RPC call rejected, "
2371 				"unknown error: %x\n",
2372 				task->tk_pid, __func__, n);
2373 			error = -EIO;
2374 			goto out_err;
2375 		}
2376 		if (--len < 0)
2377 			goto out_overflow;
2378 		switch ((n = ntohl(*p++))) {
2379 		case RPC_AUTH_REJECTEDCRED:
2380 		case RPC_AUTH_REJECTEDVERF:
2381 		case RPCSEC_GSS_CREDPROBLEM:
2382 		case RPCSEC_GSS_CTXPROBLEM:
2383 			if (!task->tk_cred_retry)
2384 				break;
2385 			task->tk_cred_retry--;
2386 			dprintk("RPC: %5u %s: retry stale creds\n",
2387 					task->tk_pid, __func__);
2388 			rpcauth_invalcred(task);
2389 			/* Ensure we obtain a new XID! */
2390 			xprt_release(task);
2391 			task->tk_action = call_reserve;
2392 			goto out_retry;
2393 		case RPC_AUTH_BADCRED:
2394 		case RPC_AUTH_BADVERF:
2395 			/* possibly garbled cred/verf? */
2396 			if (!task->tk_garb_retry)
2397 				break;
2398 			task->tk_garb_retry--;
2399 			dprintk("RPC: %5u %s: retry garbled creds\n",
2400 					task->tk_pid, __func__);
2401 			task->tk_action = call_bind;
2402 			goto out_retry;
2403 		case RPC_AUTH_TOOWEAK:
2404 			printk(KERN_NOTICE "RPC: server %s requires stronger "
2405 			       "authentication.\n",
2406 			       task->tk_xprt->servername);
2407 			break;
2408 		default:
2409 			dprintk("RPC: %5u %s: unknown auth error: %x\n",
2410 					task->tk_pid, __func__, n);
2411 			error = -EIO;
2412 		}
2413 		dprintk("RPC: %5u %s: call rejected %d\n",
2414 				task->tk_pid, __func__, n);
2415 		goto out_err;
2416 	}
2417 	p = rpcauth_checkverf(task, p);
2418 	if (IS_ERR(p)) {
2419 		error = PTR_ERR(p);
2420 		dprintk("RPC: %5u %s: auth check failed with %d\n",
2421 				task->tk_pid, __func__, error);
2422 		goto out_garbage;		/* bad verifier, retry */
2423 	}
2424 	len = p - (__be32 *)iov->iov_base - 1;
2425 	if (len < 0)
2426 		goto out_overflow;
2427 	switch ((n = ntohl(*p++))) {
2428 	case RPC_SUCCESS:
2429 		return p;
2430 	case RPC_PROG_UNAVAIL:
2431 		dprintk("RPC: %5u %s: program %u is unsupported "
2432 				"by server %s\n", task->tk_pid, __func__,
2433 				(unsigned int)clnt->cl_prog,
2434 				task->tk_xprt->servername);
2435 		error = -EPFNOSUPPORT;
2436 		goto out_err;
2437 	case RPC_PROG_MISMATCH:
2438 		dprintk("RPC: %5u %s: program %u, version %u unsupported "
2439 				"by server %s\n", task->tk_pid, __func__,
2440 				(unsigned int)clnt->cl_prog,
2441 				(unsigned int)clnt->cl_vers,
2442 				task->tk_xprt->servername);
2443 		error = -EPROTONOSUPPORT;
2444 		goto out_err;
2445 	case RPC_PROC_UNAVAIL:
2446 		dprintk("RPC: %5u %s: proc %s unsupported by program %u, "
2447 				"version %u on server %s\n",
2448 				task->tk_pid, __func__,
2449 				rpc_proc_name(task),
2450 				clnt->cl_prog, clnt->cl_vers,
2451 				task->tk_xprt->servername);
2452 		error = -EOPNOTSUPP;
2453 		goto out_err;
2454 	case RPC_GARBAGE_ARGS:
2455 		dprintk("RPC: %5u %s: server saw garbage\n",
2456 				task->tk_pid, __func__);
2457 		break;			/* retry */
2458 	default:
2459 		dprintk("RPC: %5u %s: server accept status: %x\n",
2460 				task->tk_pid, __func__, n);
2461 		/* Also retry */
2462 	}
2463 
2464 out_garbage:
2465 	clnt->cl_stats->rpcgarbage++;
2466 	if (task->tk_garb_retry) {
2467 		task->tk_garb_retry--;
2468 		dprintk("RPC: %5u %s: retrying\n",
2469 				task->tk_pid, __func__);
2470 		task->tk_action = call_bind;
2471 out_retry:
2472 		return ERR_PTR(-EAGAIN);
2473 	}
2474 out_err:
2475 	rpc_exit(task, error);
2476 	dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2477 			__func__, error);
2478 	return ERR_PTR(error);
2479 out_overflow:
2480 	dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2481 			__func__);
2482 	goto out_garbage;
2483 }
2484 
2485 static void rpcproc_encode_null(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
2486 		const void *obj)
2487 {
2488 }
2489 
2490 static int rpcproc_decode_null(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
2491 		void *obj)
2492 {
2493 	return 0;
2494 }
2495 
2496 static const struct rpc_procinfo rpcproc_null = {
2497 	.p_encode = rpcproc_encode_null,
2498 	.p_decode = rpcproc_decode_null,
2499 };
2500 
2501 static int rpc_ping(struct rpc_clnt *clnt)
2502 {
2503 	struct rpc_message msg = {
2504 		.rpc_proc = &rpcproc_null,
2505 	};
2506 	int err;
2507 	msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2508 	err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2509 	put_rpccred(msg.rpc_cred);
2510 	return err;
2511 }
2512 
2513 static
2514 struct rpc_task *rpc_call_null_helper(struct rpc_clnt *clnt,
2515 		struct rpc_xprt *xprt, struct rpc_cred *cred, int flags,
2516 		const struct rpc_call_ops *ops, void *data)
2517 {
2518 	struct rpc_message msg = {
2519 		.rpc_proc = &rpcproc_null,
2520 		.rpc_cred = cred,
2521 	};
2522 	struct rpc_task_setup task_setup_data = {
2523 		.rpc_client = clnt,
2524 		.rpc_xprt = xprt,
2525 		.rpc_message = &msg,
2526 		.callback_ops = (ops != NULL) ? ops : &rpc_default_ops,
2527 		.callback_data = data,
2528 		.flags = flags,
2529 	};
2530 
2531 	return rpc_run_task(&task_setup_data);
2532 }
2533 
2534 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2535 {
2536 	return rpc_call_null_helper(clnt, NULL, cred, flags, NULL, NULL);
2537 }
2538 EXPORT_SYMBOL_GPL(rpc_call_null);
2539 
2540 struct rpc_cb_add_xprt_calldata {
2541 	struct rpc_xprt_switch *xps;
2542 	struct rpc_xprt *xprt;
2543 };
2544 
2545 static void rpc_cb_add_xprt_done(struct rpc_task *task, void *calldata)
2546 {
2547 	struct rpc_cb_add_xprt_calldata *data = calldata;
2548 
2549 	if (task->tk_status == 0)
2550 		rpc_xprt_switch_add_xprt(data->xps, data->xprt);
2551 }
2552 
2553 static void rpc_cb_add_xprt_release(void *calldata)
2554 {
2555 	struct rpc_cb_add_xprt_calldata *data = calldata;
2556 
2557 	xprt_put(data->xprt);
2558 	xprt_switch_put(data->xps);
2559 	kfree(data);
2560 }
2561 
2562 static const struct rpc_call_ops rpc_cb_add_xprt_call_ops = {
2563 	.rpc_call_done = rpc_cb_add_xprt_done,
2564 	.rpc_release = rpc_cb_add_xprt_release,
2565 };
2566 
2567 /**
2568  * rpc_clnt_test_and_add_xprt - Test and add a new transport to a rpc_clnt
2569  * @clnt: pointer to struct rpc_clnt
2570  * @xps: pointer to struct rpc_xprt_switch,
2571  * @xprt: pointer struct rpc_xprt
2572  * @dummy: unused
2573  */
2574 int rpc_clnt_test_and_add_xprt(struct rpc_clnt *clnt,
2575 		struct rpc_xprt_switch *xps, struct rpc_xprt *xprt,
2576 		void *dummy)
2577 {
2578 	struct rpc_cb_add_xprt_calldata *data;
2579 	struct rpc_cred *cred;
2580 	struct rpc_task *task;
2581 
2582 	data = kmalloc(sizeof(*data), GFP_NOFS);
2583 	if (!data)
2584 		return -ENOMEM;
2585 	data->xps = xprt_switch_get(xps);
2586 	data->xprt = xprt_get(xprt);
2587 
2588 	cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2589 	task = rpc_call_null_helper(clnt, xprt, cred,
2590 			RPC_TASK_SOFT|RPC_TASK_SOFTCONN|RPC_TASK_ASYNC,
2591 			&rpc_cb_add_xprt_call_ops, data);
2592 	put_rpccred(cred);
2593 	if (IS_ERR(task))
2594 		return PTR_ERR(task);
2595 	rpc_put_task(task);
2596 	return 1;
2597 }
2598 EXPORT_SYMBOL_GPL(rpc_clnt_test_and_add_xprt);
2599 
2600 /**
2601  * rpc_clnt_setup_test_and_add_xprt()
2602  *
2603  * This is an rpc_clnt_add_xprt setup() function which returns 1 so:
2604  *   1) caller of the test function must dereference the rpc_xprt_switch
2605  *   and the rpc_xprt.
2606  *   2) test function must call rpc_xprt_switch_add_xprt, usually in
2607  *   the rpc_call_done routine.
2608  *
2609  * Upon success (return of 1), the test function adds the new
2610  * transport to the rpc_clnt xprt switch
2611  *
2612  * @clnt: struct rpc_clnt to get the new transport
2613  * @xps:  the rpc_xprt_switch to hold the new transport
2614  * @xprt: the rpc_xprt to test
2615  * @data: a struct rpc_add_xprt_test pointer that holds the test function
2616  *        and test function call data
2617  */
2618 int rpc_clnt_setup_test_and_add_xprt(struct rpc_clnt *clnt,
2619 				     struct rpc_xprt_switch *xps,
2620 				     struct rpc_xprt *xprt,
2621 				     void *data)
2622 {
2623 	struct rpc_cred *cred;
2624 	struct rpc_task *task;
2625 	struct rpc_add_xprt_test *xtest = (struct rpc_add_xprt_test *)data;
2626 	int status = -EADDRINUSE;
2627 
2628 	xprt = xprt_get(xprt);
2629 	xprt_switch_get(xps);
2630 
2631 	if (rpc_xprt_switch_has_addr(xps, (struct sockaddr *)&xprt->addr))
2632 		goto out_err;
2633 
2634 	/* Test the connection */
2635 	cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2636 	task = rpc_call_null_helper(clnt, xprt, cred,
2637 				    RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
2638 				    NULL, NULL);
2639 	put_rpccred(cred);
2640 	if (IS_ERR(task)) {
2641 		status = PTR_ERR(task);
2642 		goto out_err;
2643 	}
2644 	status = task->tk_status;
2645 	rpc_put_task(task);
2646 
2647 	if (status < 0)
2648 		goto out_err;
2649 
2650 	/* rpc_xprt_switch and rpc_xprt are deferrenced by add_xprt_test() */
2651 	xtest->add_xprt_test(clnt, xprt, xtest->data);
2652 
2653 	/* so that rpc_clnt_add_xprt does not call rpc_xprt_switch_add_xprt */
2654 	return 1;
2655 out_err:
2656 	xprt_put(xprt);
2657 	xprt_switch_put(xps);
2658 	pr_info("RPC:   rpc_clnt_test_xprt failed: %d addr %s not added\n",
2659 		status, xprt->address_strings[RPC_DISPLAY_ADDR]);
2660 	return status;
2661 }
2662 EXPORT_SYMBOL_GPL(rpc_clnt_setup_test_and_add_xprt);
2663 
2664 /**
2665  * rpc_clnt_add_xprt - Add a new transport to a rpc_clnt
2666  * @clnt: pointer to struct rpc_clnt
2667  * @xprtargs: pointer to struct xprt_create
2668  * @setup: callback to test and/or set up the connection
2669  * @data: pointer to setup function data
2670  *
2671  * Creates a new transport using the parameters set in args and
2672  * adds it to clnt.
2673  * If ping is set, then test that connectivity succeeds before
2674  * adding the new transport.
2675  *
2676  */
2677 int rpc_clnt_add_xprt(struct rpc_clnt *clnt,
2678 		struct xprt_create *xprtargs,
2679 		int (*setup)(struct rpc_clnt *,
2680 			struct rpc_xprt_switch *,
2681 			struct rpc_xprt *,
2682 			void *),
2683 		void *data)
2684 {
2685 	struct rpc_xprt_switch *xps;
2686 	struct rpc_xprt *xprt;
2687 	unsigned long connect_timeout;
2688 	unsigned long reconnect_timeout;
2689 	unsigned char resvport;
2690 	int ret = 0;
2691 
2692 	rcu_read_lock();
2693 	xps = xprt_switch_get(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
2694 	xprt = xprt_iter_xprt(&clnt->cl_xpi);
2695 	if (xps == NULL || xprt == NULL) {
2696 		rcu_read_unlock();
2697 		return -EAGAIN;
2698 	}
2699 	resvport = xprt->resvport;
2700 	connect_timeout = xprt->connect_timeout;
2701 	reconnect_timeout = xprt->max_reconnect_timeout;
2702 	rcu_read_unlock();
2703 
2704 	xprt = xprt_create_transport(xprtargs);
2705 	if (IS_ERR(xprt)) {
2706 		ret = PTR_ERR(xprt);
2707 		goto out_put_switch;
2708 	}
2709 	xprt->resvport = resvport;
2710 	if (xprt->ops->set_connect_timeout != NULL)
2711 		xprt->ops->set_connect_timeout(xprt,
2712 				connect_timeout,
2713 				reconnect_timeout);
2714 
2715 	rpc_xprt_switch_set_roundrobin(xps);
2716 	if (setup) {
2717 		ret = setup(clnt, xps, xprt, data);
2718 		if (ret != 0)
2719 			goto out_put_xprt;
2720 	}
2721 	rpc_xprt_switch_add_xprt(xps, xprt);
2722 out_put_xprt:
2723 	xprt_put(xprt);
2724 out_put_switch:
2725 	xprt_switch_put(xps);
2726 	return ret;
2727 }
2728 EXPORT_SYMBOL_GPL(rpc_clnt_add_xprt);
2729 
2730 struct connect_timeout_data {
2731 	unsigned long connect_timeout;
2732 	unsigned long reconnect_timeout;
2733 };
2734 
2735 static int
2736 rpc_xprt_set_connect_timeout(struct rpc_clnt *clnt,
2737 		struct rpc_xprt *xprt,
2738 		void *data)
2739 {
2740 	struct connect_timeout_data *timeo = data;
2741 
2742 	if (xprt->ops->set_connect_timeout)
2743 		xprt->ops->set_connect_timeout(xprt,
2744 				timeo->connect_timeout,
2745 				timeo->reconnect_timeout);
2746 	return 0;
2747 }
2748 
2749 void
2750 rpc_set_connect_timeout(struct rpc_clnt *clnt,
2751 		unsigned long connect_timeout,
2752 		unsigned long reconnect_timeout)
2753 {
2754 	struct connect_timeout_data timeout = {
2755 		.connect_timeout = connect_timeout,
2756 		.reconnect_timeout = reconnect_timeout,
2757 	};
2758 	rpc_clnt_iterate_for_each_xprt(clnt,
2759 			rpc_xprt_set_connect_timeout,
2760 			&timeout);
2761 }
2762 EXPORT_SYMBOL_GPL(rpc_set_connect_timeout);
2763 
2764 void rpc_clnt_xprt_switch_put(struct rpc_clnt *clnt)
2765 {
2766 	rcu_read_lock();
2767 	xprt_switch_put(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
2768 	rcu_read_unlock();
2769 }
2770 EXPORT_SYMBOL_GPL(rpc_clnt_xprt_switch_put);
2771 
2772 void rpc_clnt_xprt_switch_add_xprt(struct rpc_clnt *clnt, struct rpc_xprt *xprt)
2773 {
2774 	rcu_read_lock();
2775 	rpc_xprt_switch_add_xprt(rcu_dereference(clnt->cl_xpi.xpi_xpswitch),
2776 				 xprt);
2777 	rcu_read_unlock();
2778 }
2779 EXPORT_SYMBOL_GPL(rpc_clnt_xprt_switch_add_xprt);
2780 
2781 bool rpc_clnt_xprt_switch_has_addr(struct rpc_clnt *clnt,
2782 				   const struct sockaddr *sap)
2783 {
2784 	struct rpc_xprt_switch *xps;
2785 	bool ret;
2786 
2787 	rcu_read_lock();
2788 	xps = rcu_dereference(clnt->cl_xpi.xpi_xpswitch);
2789 	ret = rpc_xprt_switch_has_addr(xps, sap);
2790 	rcu_read_unlock();
2791 	return ret;
2792 }
2793 EXPORT_SYMBOL_GPL(rpc_clnt_xprt_switch_has_addr);
2794 
2795 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
2796 static void rpc_show_header(void)
2797 {
2798 	printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2799 		"-timeout ---ops--\n");
2800 }
2801 
2802 static void rpc_show_task(const struct rpc_clnt *clnt,
2803 			  const struct rpc_task *task)
2804 {
2805 	const char *rpc_waitq = "none";
2806 
2807 	if (RPC_IS_QUEUED(task))
2808 		rpc_waitq = rpc_qname(task->tk_waitqueue);
2809 
2810 	printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2811 		task->tk_pid, task->tk_flags, task->tk_status,
2812 		clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2813 		clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
2814 		task->tk_action, rpc_waitq);
2815 }
2816 
2817 void rpc_show_tasks(struct net *net)
2818 {
2819 	struct rpc_clnt *clnt;
2820 	struct rpc_task *task;
2821 	int header = 0;
2822 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2823 
2824 	spin_lock(&sn->rpc_client_lock);
2825 	list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2826 		spin_lock(&clnt->cl_lock);
2827 		list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2828 			if (!header) {
2829 				rpc_show_header();
2830 				header++;
2831 			}
2832 			rpc_show_task(clnt, task);
2833 		}
2834 		spin_unlock(&clnt->cl_lock);
2835 	}
2836 	spin_unlock(&sn->rpc_client_lock);
2837 }
2838 #endif
2839 
2840 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
2841 static int
2842 rpc_clnt_swap_activate_callback(struct rpc_clnt *clnt,
2843 		struct rpc_xprt *xprt,
2844 		void *dummy)
2845 {
2846 	return xprt_enable_swap(xprt);
2847 }
2848 
2849 int
2850 rpc_clnt_swap_activate(struct rpc_clnt *clnt)
2851 {
2852 	if (atomic_inc_return(&clnt->cl_swapper) == 1)
2853 		return rpc_clnt_iterate_for_each_xprt(clnt,
2854 				rpc_clnt_swap_activate_callback, NULL);
2855 	return 0;
2856 }
2857 EXPORT_SYMBOL_GPL(rpc_clnt_swap_activate);
2858 
2859 static int
2860 rpc_clnt_swap_deactivate_callback(struct rpc_clnt *clnt,
2861 		struct rpc_xprt *xprt,
2862 		void *dummy)
2863 {
2864 	xprt_disable_swap(xprt);
2865 	return 0;
2866 }
2867 
2868 void
2869 rpc_clnt_swap_deactivate(struct rpc_clnt *clnt)
2870 {
2871 	if (atomic_dec_if_positive(&clnt->cl_swapper) == 0)
2872 		rpc_clnt_iterate_for_each_xprt(clnt,
2873 				rpc_clnt_swap_deactivate_callback, NULL);
2874 }
2875 EXPORT_SYMBOL_GPL(rpc_clnt_swap_deactivate);
2876 #endif /* CONFIG_SUNRPC_SWAP */
2877