xref: /linux/net/sunrpc/clnt.c (revision 3a755ebcc2557e22b895b8976257f682c653db1d)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/net/sunrpc/clnt.c
4  *
5  *  This file contains the high-level RPC interface.
6  *  It is modeled as a finite state machine to support both synchronous
7  *  and asynchronous requests.
8  *
9  *  -	RPC header generation and argument serialization.
10  *  -	Credential refresh.
11  *  -	TCP connect handling.
12  *  -	Retry of operation when it is suspected the operation failed because
13  *	of uid squashing on the server, or when the credentials were stale
14  *	and need to be refreshed, or when a packet was damaged in transit.
15  *	This may be have to be moved to the VFS layer.
16  *
17  *  Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
18  *  Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
19  */
20 
21 
22 #include <linux/module.h>
23 #include <linux/types.h>
24 #include <linux/kallsyms.h>
25 #include <linux/mm.h>
26 #include <linux/namei.h>
27 #include <linux/mount.h>
28 #include <linux/slab.h>
29 #include <linux/rcupdate.h>
30 #include <linux/utsname.h>
31 #include <linux/workqueue.h>
32 #include <linux/in.h>
33 #include <linux/in6.h>
34 #include <linux/un.h>
35 
36 #include <linux/sunrpc/clnt.h>
37 #include <linux/sunrpc/addr.h>
38 #include <linux/sunrpc/rpc_pipe_fs.h>
39 #include <linux/sunrpc/metrics.h>
40 #include <linux/sunrpc/bc_xprt.h>
41 #include <trace/events/sunrpc.h>
42 
43 #include "sunrpc.h"
44 #include "sysfs.h"
45 #include "netns.h"
46 
47 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
48 # define RPCDBG_FACILITY	RPCDBG_CALL
49 #endif
50 
51 /*
52  * All RPC clients are linked into this list
53  */
54 
55 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait);
56 
57 
58 static void	call_start(struct rpc_task *task);
59 static void	call_reserve(struct rpc_task *task);
60 static void	call_reserveresult(struct rpc_task *task);
61 static void	call_allocate(struct rpc_task *task);
62 static void	call_encode(struct rpc_task *task);
63 static void	call_decode(struct rpc_task *task);
64 static void	call_bind(struct rpc_task *task);
65 static void	call_bind_status(struct rpc_task *task);
66 static void	call_transmit(struct rpc_task *task);
67 static void	call_status(struct rpc_task *task);
68 static void	call_transmit_status(struct rpc_task *task);
69 static void	call_refresh(struct rpc_task *task);
70 static void	call_refreshresult(struct rpc_task *task);
71 static void	call_connect(struct rpc_task *task);
72 static void	call_connect_status(struct rpc_task *task);
73 
74 static int	rpc_encode_header(struct rpc_task *task,
75 				  struct xdr_stream *xdr);
76 static int	rpc_decode_header(struct rpc_task *task,
77 				  struct xdr_stream *xdr);
78 static int	rpc_ping(struct rpc_clnt *clnt);
79 static int	rpc_ping_noreply(struct rpc_clnt *clnt);
80 static void	rpc_check_timeout(struct rpc_task *task);
81 
82 static void rpc_register_client(struct rpc_clnt *clnt)
83 {
84 	struct net *net = rpc_net_ns(clnt);
85 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
86 
87 	spin_lock(&sn->rpc_client_lock);
88 	list_add(&clnt->cl_clients, &sn->all_clients);
89 	spin_unlock(&sn->rpc_client_lock);
90 }
91 
92 static void rpc_unregister_client(struct rpc_clnt *clnt)
93 {
94 	struct net *net = rpc_net_ns(clnt);
95 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
96 
97 	spin_lock(&sn->rpc_client_lock);
98 	list_del(&clnt->cl_clients);
99 	spin_unlock(&sn->rpc_client_lock);
100 }
101 
102 static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
103 {
104 	rpc_remove_client_dir(clnt);
105 }
106 
107 static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt)
108 {
109 	struct net *net = rpc_net_ns(clnt);
110 	struct super_block *pipefs_sb;
111 
112 	pipefs_sb = rpc_get_sb_net(net);
113 	if (pipefs_sb) {
114 		__rpc_clnt_remove_pipedir(clnt);
115 		rpc_put_sb_net(net);
116 	}
117 }
118 
119 static struct dentry *rpc_setup_pipedir_sb(struct super_block *sb,
120 				    struct rpc_clnt *clnt)
121 {
122 	static uint32_t clntid;
123 	const char *dir_name = clnt->cl_program->pipe_dir_name;
124 	char name[15];
125 	struct dentry *dir, *dentry;
126 
127 	dir = rpc_d_lookup_sb(sb, dir_name);
128 	if (dir == NULL) {
129 		pr_info("RPC: pipefs directory doesn't exist: %s\n", dir_name);
130 		return dir;
131 	}
132 	for (;;) {
133 		snprintf(name, sizeof(name), "clnt%x", (unsigned int)clntid++);
134 		name[sizeof(name) - 1] = '\0';
135 		dentry = rpc_create_client_dir(dir, name, clnt);
136 		if (!IS_ERR(dentry))
137 			break;
138 		if (dentry == ERR_PTR(-EEXIST))
139 			continue;
140 		printk(KERN_INFO "RPC: Couldn't create pipefs entry"
141 				" %s/%s, error %ld\n",
142 				dir_name, name, PTR_ERR(dentry));
143 		break;
144 	}
145 	dput(dir);
146 	return dentry;
147 }
148 
149 static int
150 rpc_setup_pipedir(struct super_block *pipefs_sb, struct rpc_clnt *clnt)
151 {
152 	struct dentry *dentry;
153 
154 	if (clnt->cl_program->pipe_dir_name != NULL) {
155 		dentry = rpc_setup_pipedir_sb(pipefs_sb, clnt);
156 		if (IS_ERR(dentry))
157 			return PTR_ERR(dentry);
158 	}
159 	return 0;
160 }
161 
162 static int rpc_clnt_skip_event(struct rpc_clnt *clnt, unsigned long event)
163 {
164 	if (clnt->cl_program->pipe_dir_name == NULL)
165 		return 1;
166 
167 	switch (event) {
168 	case RPC_PIPEFS_MOUNT:
169 		if (clnt->cl_pipedir_objects.pdh_dentry != NULL)
170 			return 1;
171 		if (refcount_read(&clnt->cl_count) == 0)
172 			return 1;
173 		break;
174 	case RPC_PIPEFS_UMOUNT:
175 		if (clnt->cl_pipedir_objects.pdh_dentry == NULL)
176 			return 1;
177 		break;
178 	}
179 	return 0;
180 }
181 
182 static int __rpc_clnt_handle_event(struct rpc_clnt *clnt, unsigned long event,
183 				   struct super_block *sb)
184 {
185 	struct dentry *dentry;
186 
187 	switch (event) {
188 	case RPC_PIPEFS_MOUNT:
189 		dentry = rpc_setup_pipedir_sb(sb, clnt);
190 		if (!dentry)
191 			return -ENOENT;
192 		if (IS_ERR(dentry))
193 			return PTR_ERR(dentry);
194 		break;
195 	case RPC_PIPEFS_UMOUNT:
196 		__rpc_clnt_remove_pipedir(clnt);
197 		break;
198 	default:
199 		printk(KERN_ERR "%s: unknown event: %ld\n", __func__, event);
200 		return -ENOTSUPP;
201 	}
202 	return 0;
203 }
204 
205 static int __rpc_pipefs_event(struct rpc_clnt *clnt, unsigned long event,
206 				struct super_block *sb)
207 {
208 	int error = 0;
209 
210 	for (;; clnt = clnt->cl_parent) {
211 		if (!rpc_clnt_skip_event(clnt, event))
212 			error = __rpc_clnt_handle_event(clnt, event, sb);
213 		if (error || clnt == clnt->cl_parent)
214 			break;
215 	}
216 	return error;
217 }
218 
219 static struct rpc_clnt *rpc_get_client_for_event(struct net *net, int event)
220 {
221 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
222 	struct rpc_clnt *clnt;
223 
224 	spin_lock(&sn->rpc_client_lock);
225 	list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
226 		if (rpc_clnt_skip_event(clnt, event))
227 			continue;
228 		spin_unlock(&sn->rpc_client_lock);
229 		return clnt;
230 	}
231 	spin_unlock(&sn->rpc_client_lock);
232 	return NULL;
233 }
234 
235 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
236 			    void *ptr)
237 {
238 	struct super_block *sb = ptr;
239 	struct rpc_clnt *clnt;
240 	int error = 0;
241 
242 	while ((clnt = rpc_get_client_for_event(sb->s_fs_info, event))) {
243 		error = __rpc_pipefs_event(clnt, event, sb);
244 		if (error)
245 			break;
246 	}
247 	return error;
248 }
249 
250 static struct notifier_block rpc_clients_block = {
251 	.notifier_call	= rpc_pipefs_event,
252 	.priority	= SUNRPC_PIPEFS_RPC_PRIO,
253 };
254 
255 int rpc_clients_notifier_register(void)
256 {
257 	return rpc_pipefs_notifier_register(&rpc_clients_block);
258 }
259 
260 void rpc_clients_notifier_unregister(void)
261 {
262 	return rpc_pipefs_notifier_unregister(&rpc_clients_block);
263 }
264 
265 static struct rpc_xprt *rpc_clnt_set_transport(struct rpc_clnt *clnt,
266 		struct rpc_xprt *xprt,
267 		const struct rpc_timeout *timeout)
268 {
269 	struct rpc_xprt *old;
270 
271 	spin_lock(&clnt->cl_lock);
272 	old = rcu_dereference_protected(clnt->cl_xprt,
273 			lockdep_is_held(&clnt->cl_lock));
274 
275 	if (!xprt_bound(xprt))
276 		clnt->cl_autobind = 1;
277 
278 	clnt->cl_timeout = timeout;
279 	rcu_assign_pointer(clnt->cl_xprt, xprt);
280 	spin_unlock(&clnt->cl_lock);
281 
282 	return old;
283 }
284 
285 static void rpc_clnt_set_nodename(struct rpc_clnt *clnt, const char *nodename)
286 {
287 	clnt->cl_nodelen = strlcpy(clnt->cl_nodename,
288 			nodename, sizeof(clnt->cl_nodename));
289 }
290 
291 static int rpc_client_register(struct rpc_clnt *clnt,
292 			       rpc_authflavor_t pseudoflavor,
293 			       const char *client_name)
294 {
295 	struct rpc_auth_create_args auth_args = {
296 		.pseudoflavor = pseudoflavor,
297 		.target_name = client_name,
298 	};
299 	struct rpc_auth *auth;
300 	struct net *net = rpc_net_ns(clnt);
301 	struct super_block *pipefs_sb;
302 	int err;
303 
304 	rpc_clnt_debugfs_register(clnt);
305 
306 	pipefs_sb = rpc_get_sb_net(net);
307 	if (pipefs_sb) {
308 		err = rpc_setup_pipedir(pipefs_sb, clnt);
309 		if (err)
310 			goto out;
311 	}
312 
313 	rpc_register_client(clnt);
314 	if (pipefs_sb)
315 		rpc_put_sb_net(net);
316 
317 	auth = rpcauth_create(&auth_args, clnt);
318 	if (IS_ERR(auth)) {
319 		dprintk("RPC:       Couldn't create auth handle (flavor %u)\n",
320 				pseudoflavor);
321 		err = PTR_ERR(auth);
322 		goto err_auth;
323 	}
324 	return 0;
325 err_auth:
326 	pipefs_sb = rpc_get_sb_net(net);
327 	rpc_unregister_client(clnt);
328 	__rpc_clnt_remove_pipedir(clnt);
329 out:
330 	if (pipefs_sb)
331 		rpc_put_sb_net(net);
332 	rpc_sysfs_client_destroy(clnt);
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 	err = rpciod_up();
373 	if (err)
374 		goto out_no_rpciod;
375 
376 	err = -EINVAL;
377 	if (args->version >= program->nrvers)
378 		goto out_err;
379 	version = program->version[args->version];
380 	if (version == NULL)
381 		goto out_err;
382 
383 	err = -ENOMEM;
384 	clnt = kzalloc(sizeof(*clnt), GFP_KERNEL);
385 	if (!clnt)
386 		goto out_err;
387 	clnt->cl_parent = parent ? : clnt;
388 
389 	err = rpc_alloc_clid(clnt);
390 	if (err)
391 		goto out_no_clid;
392 
393 	clnt->cl_cred	  = get_cred(args->cred);
394 	clnt->cl_procinfo = version->procs;
395 	clnt->cl_maxproc  = version->nrprocs;
396 	clnt->cl_prog     = args->prognumber ? : program->number;
397 	clnt->cl_vers     = version->number;
398 	clnt->cl_stats    = program->stats;
399 	clnt->cl_metrics  = rpc_alloc_iostats(clnt);
400 	rpc_init_pipe_dir_head(&clnt->cl_pipedir_objects);
401 	err = -ENOMEM;
402 	if (clnt->cl_metrics == NULL)
403 		goto out_no_stats;
404 	clnt->cl_program  = program;
405 	INIT_LIST_HEAD(&clnt->cl_tasks);
406 	spin_lock_init(&clnt->cl_lock);
407 
408 	timeout = xprt->timeout;
409 	if (args->timeout != NULL) {
410 		memcpy(&clnt->cl_timeout_default, args->timeout,
411 				sizeof(clnt->cl_timeout_default));
412 		timeout = &clnt->cl_timeout_default;
413 	}
414 
415 	rpc_clnt_set_transport(clnt, xprt, timeout);
416 	xprt->main = true;
417 	xprt_iter_init(&clnt->cl_xpi, xps);
418 	xprt_switch_put(xps);
419 
420 	clnt->cl_rtt = &clnt->cl_rtt_default;
421 	rpc_init_rtt(&clnt->cl_rtt_default, clnt->cl_timeout->to_initval);
422 
423 	refcount_set(&clnt->cl_count, 1);
424 
425 	if (nodename == NULL)
426 		nodename = utsname()->nodename;
427 	/* save the nodename */
428 	rpc_clnt_set_nodename(clnt, nodename);
429 
430 	rpc_sysfs_client_setup(clnt, xps, rpc_net_ns(clnt));
431 	err = rpc_client_register(clnt, args->authflavor, args->client_name);
432 	if (err)
433 		goto out_no_path;
434 	if (parent)
435 		refcount_inc(&parent->cl_count);
436 
437 	trace_rpc_clnt_new(clnt, xprt, program->name, args->servername);
438 	return clnt;
439 
440 out_no_path:
441 	rpc_free_iostats(clnt->cl_metrics);
442 out_no_stats:
443 	put_cred(clnt->cl_cred);
444 	rpc_free_clid(clnt);
445 out_no_clid:
446 	kfree(clnt);
447 out_err:
448 	rpciod_down();
449 out_no_rpciod:
450 	xprt_switch_put(xps);
451 	xprt_put(xprt);
452 	trace_rpc_clnt_new_err(program->name, args->servername, err);
453 	return ERR_PTR(err);
454 }
455 
456 static struct rpc_clnt *rpc_create_xprt(struct rpc_create_args *args,
457 					struct rpc_xprt *xprt)
458 {
459 	struct rpc_clnt *clnt = NULL;
460 	struct rpc_xprt_switch *xps;
461 
462 	if (args->bc_xprt && args->bc_xprt->xpt_bc_xps) {
463 		WARN_ON_ONCE(!(args->protocol & XPRT_TRANSPORT_BC));
464 		xps = args->bc_xprt->xpt_bc_xps;
465 		xprt_switch_get(xps);
466 	} else {
467 		xps = xprt_switch_alloc(xprt, GFP_KERNEL);
468 		if (xps == NULL) {
469 			xprt_put(xprt);
470 			return ERR_PTR(-ENOMEM);
471 		}
472 		if (xprt->bc_xprt) {
473 			xprt_switch_get(xps);
474 			xprt->bc_xprt->xpt_bc_xps = xps;
475 		}
476 	}
477 	clnt = rpc_new_client(args, xps, xprt, NULL);
478 	if (IS_ERR(clnt))
479 		return clnt;
480 
481 	if (!(args->flags & RPC_CLNT_CREATE_NOPING)) {
482 		int err = rpc_ping(clnt);
483 		if (err != 0) {
484 			rpc_shutdown_client(clnt);
485 			return ERR_PTR(err);
486 		}
487 	} else if (args->flags & RPC_CLNT_CREATE_CONNECTED) {
488 		int err = rpc_ping_noreply(clnt);
489 		if (err != 0) {
490 			rpc_shutdown_client(clnt);
491 			return ERR_PTR(err);
492 		}
493 	}
494 
495 	clnt->cl_softrtry = 1;
496 	if (args->flags & (RPC_CLNT_CREATE_HARDRTRY|RPC_CLNT_CREATE_SOFTERR)) {
497 		clnt->cl_softrtry = 0;
498 		if (args->flags & RPC_CLNT_CREATE_SOFTERR)
499 			clnt->cl_softerr = 1;
500 	}
501 
502 	if (args->flags & RPC_CLNT_CREATE_AUTOBIND)
503 		clnt->cl_autobind = 1;
504 	if (args->flags & RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT)
505 		clnt->cl_noretranstimeo = 1;
506 	if (args->flags & RPC_CLNT_CREATE_DISCRTRY)
507 		clnt->cl_discrtry = 1;
508 	if (!(args->flags & RPC_CLNT_CREATE_QUIET))
509 		clnt->cl_chatty = 1;
510 
511 	return clnt;
512 }
513 
514 /**
515  * rpc_create - create an RPC client and transport with one call
516  * @args: rpc_clnt create argument structure
517  *
518  * Creates and initializes an RPC transport and an RPC client.
519  *
520  * It can ping the server in order to determine if it is up, and to see if
521  * it supports this program and version.  RPC_CLNT_CREATE_NOPING disables
522  * this behavior so asynchronous tasks can also use rpc_create.
523  */
524 struct rpc_clnt *rpc_create(struct rpc_create_args *args)
525 {
526 	struct rpc_xprt *xprt;
527 	struct xprt_create xprtargs = {
528 		.net = args->net,
529 		.ident = args->protocol,
530 		.srcaddr = args->saddress,
531 		.dstaddr = args->address,
532 		.addrlen = args->addrsize,
533 		.servername = args->servername,
534 		.bc_xprt = args->bc_xprt,
535 	};
536 	char servername[48];
537 	struct rpc_clnt *clnt;
538 	int i;
539 
540 	if (args->bc_xprt) {
541 		WARN_ON_ONCE(!(args->protocol & XPRT_TRANSPORT_BC));
542 		xprt = args->bc_xprt->xpt_bc_xprt;
543 		if (xprt) {
544 			xprt_get(xprt);
545 			return rpc_create_xprt(args, xprt);
546 		}
547 	}
548 
549 	if (args->flags & RPC_CLNT_CREATE_INFINITE_SLOTS)
550 		xprtargs.flags |= XPRT_CREATE_INFINITE_SLOTS;
551 	if (args->flags & RPC_CLNT_CREATE_NO_IDLE_TIMEOUT)
552 		xprtargs.flags |= XPRT_CREATE_NO_IDLE_TIMEOUT;
553 	/*
554 	 * If the caller chooses not to specify a hostname, whip
555 	 * up a string representation of the passed-in address.
556 	 */
557 	if (xprtargs.servername == NULL) {
558 		struct sockaddr_un *sun =
559 				(struct sockaddr_un *)args->address;
560 		struct sockaddr_in *sin =
561 				(struct sockaddr_in *)args->address;
562 		struct sockaddr_in6 *sin6 =
563 				(struct sockaddr_in6 *)args->address;
564 
565 		servername[0] = '\0';
566 		switch (args->address->sa_family) {
567 		case AF_LOCAL:
568 			snprintf(servername, sizeof(servername), "%s",
569 				 sun->sun_path);
570 			break;
571 		case AF_INET:
572 			snprintf(servername, sizeof(servername), "%pI4",
573 				 &sin->sin_addr.s_addr);
574 			break;
575 		case AF_INET6:
576 			snprintf(servername, sizeof(servername), "%pI6",
577 				 &sin6->sin6_addr);
578 			break;
579 		default:
580 			/* caller wants default server name, but
581 			 * address family isn't recognized. */
582 			return ERR_PTR(-EINVAL);
583 		}
584 		xprtargs.servername = servername;
585 	}
586 
587 	xprt = xprt_create_transport(&xprtargs);
588 	if (IS_ERR(xprt))
589 		return (struct rpc_clnt *)xprt;
590 
591 	/*
592 	 * By default, kernel RPC client connects from a reserved port.
593 	 * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
594 	 * but it is always enabled for rpciod, which handles the connect
595 	 * operation.
596 	 */
597 	xprt->resvport = 1;
598 	if (args->flags & RPC_CLNT_CREATE_NONPRIVPORT)
599 		xprt->resvport = 0;
600 	xprt->reuseport = 0;
601 	if (args->flags & RPC_CLNT_CREATE_REUSEPORT)
602 		xprt->reuseport = 1;
603 
604 	clnt = rpc_create_xprt(args, xprt);
605 	if (IS_ERR(clnt) || args->nconnect <= 1)
606 		return clnt;
607 
608 	for (i = 0; i < args->nconnect - 1; i++) {
609 		if (rpc_clnt_add_xprt(clnt, &xprtargs, NULL, NULL) < 0)
610 			break;
611 	}
612 	return clnt;
613 }
614 EXPORT_SYMBOL_GPL(rpc_create);
615 
616 /*
617  * This function clones the RPC client structure. It allows us to share the
618  * same transport while varying parameters such as the authentication
619  * flavour.
620  */
621 static struct rpc_clnt *__rpc_clone_client(struct rpc_create_args *args,
622 					   struct rpc_clnt *clnt)
623 {
624 	struct rpc_xprt_switch *xps;
625 	struct rpc_xprt *xprt;
626 	struct rpc_clnt *new;
627 	int err;
628 
629 	err = -ENOMEM;
630 	rcu_read_lock();
631 	xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
632 	xps = xprt_switch_get(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
633 	rcu_read_unlock();
634 	if (xprt == NULL || xps == NULL) {
635 		xprt_put(xprt);
636 		xprt_switch_put(xps);
637 		goto out_err;
638 	}
639 	args->servername = xprt->servername;
640 	args->nodename = clnt->cl_nodename;
641 
642 	new = rpc_new_client(args, xps, xprt, clnt);
643 	if (IS_ERR(new))
644 		return new;
645 
646 	/* Turn off autobind on clones */
647 	new->cl_autobind = 0;
648 	new->cl_softrtry = clnt->cl_softrtry;
649 	new->cl_softerr = clnt->cl_softerr;
650 	new->cl_noretranstimeo = clnt->cl_noretranstimeo;
651 	new->cl_discrtry = clnt->cl_discrtry;
652 	new->cl_chatty = clnt->cl_chatty;
653 	new->cl_principal = clnt->cl_principal;
654 	return new;
655 
656 out_err:
657 	trace_rpc_clnt_clone_err(clnt, err);
658 	return ERR_PTR(err);
659 }
660 
661 /**
662  * rpc_clone_client - Clone an RPC client structure
663  *
664  * @clnt: RPC client whose parameters are copied
665  *
666  * Returns a fresh RPC client or an ERR_PTR.
667  */
668 struct rpc_clnt *rpc_clone_client(struct rpc_clnt *clnt)
669 {
670 	struct rpc_create_args args = {
671 		.program	= clnt->cl_program,
672 		.prognumber	= clnt->cl_prog,
673 		.version	= clnt->cl_vers,
674 		.authflavor	= clnt->cl_auth->au_flavor,
675 		.cred		= clnt->cl_cred,
676 	};
677 	return __rpc_clone_client(&args, clnt);
678 }
679 EXPORT_SYMBOL_GPL(rpc_clone_client);
680 
681 /**
682  * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
683  *
684  * @clnt: RPC client whose parameters are copied
685  * @flavor: security flavor for new client
686  *
687  * Returns a fresh RPC client or an ERR_PTR.
688  */
689 struct rpc_clnt *
690 rpc_clone_client_set_auth(struct rpc_clnt *clnt, rpc_authflavor_t flavor)
691 {
692 	struct rpc_create_args args = {
693 		.program	= clnt->cl_program,
694 		.prognumber	= clnt->cl_prog,
695 		.version	= clnt->cl_vers,
696 		.authflavor	= flavor,
697 		.cred		= clnt->cl_cred,
698 	};
699 	return __rpc_clone_client(&args, clnt);
700 }
701 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth);
702 
703 /**
704  * rpc_switch_client_transport: switch the RPC transport on the fly
705  * @clnt: pointer to a struct rpc_clnt
706  * @args: pointer to the new transport arguments
707  * @timeout: pointer to the new timeout parameters
708  *
709  * This function allows the caller to switch the RPC transport for the
710  * rpc_clnt structure 'clnt' to allow it to connect to a mirrored NFS
711  * server, for instance.  It assumes that the caller has ensured that
712  * there are no active RPC tasks by using some form of locking.
713  *
714  * Returns zero if "clnt" is now using the new xprt.  Otherwise a
715  * negative errno is returned, and "clnt" continues to use the old
716  * xprt.
717  */
718 int rpc_switch_client_transport(struct rpc_clnt *clnt,
719 		struct xprt_create *args,
720 		const struct rpc_timeout *timeout)
721 {
722 	const struct rpc_timeout *old_timeo;
723 	rpc_authflavor_t pseudoflavor;
724 	struct rpc_xprt_switch *xps, *oldxps;
725 	struct rpc_xprt *xprt, *old;
726 	struct rpc_clnt *parent;
727 	int err;
728 
729 	xprt = xprt_create_transport(args);
730 	if (IS_ERR(xprt))
731 		return PTR_ERR(xprt);
732 
733 	xps = xprt_switch_alloc(xprt, GFP_KERNEL);
734 	if (xps == NULL) {
735 		xprt_put(xprt);
736 		return -ENOMEM;
737 	}
738 
739 	pseudoflavor = clnt->cl_auth->au_flavor;
740 
741 	old_timeo = clnt->cl_timeout;
742 	old = rpc_clnt_set_transport(clnt, xprt, timeout);
743 	oldxps = xprt_iter_xchg_switch(&clnt->cl_xpi, xps);
744 
745 	rpc_unregister_client(clnt);
746 	__rpc_clnt_remove_pipedir(clnt);
747 	rpc_sysfs_client_destroy(clnt);
748 	rpc_clnt_debugfs_unregister(clnt);
749 
750 	/*
751 	 * A new transport was created.  "clnt" therefore
752 	 * becomes the root of a new cl_parent tree.  clnt's
753 	 * children, if it has any, still point to the old xprt.
754 	 */
755 	parent = clnt->cl_parent;
756 	clnt->cl_parent = clnt;
757 
758 	/*
759 	 * The old rpc_auth cache cannot be re-used.  GSS
760 	 * contexts in particular are between a single
761 	 * client and server.
762 	 */
763 	err = rpc_client_register(clnt, pseudoflavor, NULL);
764 	if (err)
765 		goto out_revert;
766 
767 	synchronize_rcu();
768 	if (parent != clnt)
769 		rpc_release_client(parent);
770 	xprt_switch_put(oldxps);
771 	xprt_put(old);
772 	trace_rpc_clnt_replace_xprt(clnt);
773 	return 0;
774 
775 out_revert:
776 	xps = xprt_iter_xchg_switch(&clnt->cl_xpi, oldxps);
777 	rpc_clnt_set_transport(clnt, old, old_timeo);
778 	clnt->cl_parent = parent;
779 	rpc_client_register(clnt, pseudoflavor, NULL);
780 	xprt_switch_put(xps);
781 	xprt_put(xprt);
782 	trace_rpc_clnt_replace_xprt_err(clnt);
783 	return err;
784 }
785 EXPORT_SYMBOL_GPL(rpc_switch_client_transport);
786 
787 static
788 int rpc_clnt_xprt_iter_init(struct rpc_clnt *clnt, struct rpc_xprt_iter *xpi)
789 {
790 	struct rpc_xprt_switch *xps;
791 
792 	rcu_read_lock();
793 	xps = xprt_switch_get(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
794 	rcu_read_unlock();
795 	if (xps == NULL)
796 		return -EAGAIN;
797 	xprt_iter_init_listall(xpi, xps);
798 	xprt_switch_put(xps);
799 	return 0;
800 }
801 
802 /**
803  * rpc_clnt_iterate_for_each_xprt - Apply a function to all transports
804  * @clnt: pointer to client
805  * @fn: function to apply
806  * @data: void pointer to function data
807  *
808  * Iterates through the list of RPC transports currently attached to the
809  * client and applies the function fn(clnt, xprt, data).
810  *
811  * On error, the iteration stops, and the function returns the error value.
812  */
813 int rpc_clnt_iterate_for_each_xprt(struct rpc_clnt *clnt,
814 		int (*fn)(struct rpc_clnt *, struct rpc_xprt *, void *),
815 		void *data)
816 {
817 	struct rpc_xprt_iter xpi;
818 	int ret;
819 
820 	ret = rpc_clnt_xprt_iter_init(clnt, &xpi);
821 	if (ret)
822 		return ret;
823 	for (;;) {
824 		struct rpc_xprt *xprt = xprt_iter_get_next(&xpi);
825 
826 		if (!xprt)
827 			break;
828 		ret = fn(clnt, xprt, data);
829 		xprt_put(xprt);
830 		if (ret < 0)
831 			break;
832 	}
833 	xprt_iter_destroy(&xpi);
834 	return ret;
835 }
836 EXPORT_SYMBOL_GPL(rpc_clnt_iterate_for_each_xprt);
837 
838 /*
839  * Kill all tasks for the given client.
840  * XXX: kill their descendants as well?
841  */
842 void rpc_killall_tasks(struct rpc_clnt *clnt)
843 {
844 	struct rpc_task	*rovr;
845 
846 
847 	if (list_empty(&clnt->cl_tasks))
848 		return;
849 
850 	/*
851 	 * Spin lock all_tasks to prevent changes...
852 	 */
853 	trace_rpc_clnt_killall(clnt);
854 	spin_lock(&clnt->cl_lock);
855 	list_for_each_entry(rovr, &clnt->cl_tasks, tk_task)
856 		rpc_signal_task(rovr);
857 	spin_unlock(&clnt->cl_lock);
858 }
859 EXPORT_SYMBOL_GPL(rpc_killall_tasks);
860 
861 /*
862  * Properly shut down an RPC client, terminating all outstanding
863  * requests.
864  */
865 void rpc_shutdown_client(struct rpc_clnt *clnt)
866 {
867 	might_sleep();
868 
869 	trace_rpc_clnt_shutdown(clnt);
870 
871 	while (!list_empty(&clnt->cl_tasks)) {
872 		rpc_killall_tasks(clnt);
873 		wait_event_timeout(destroy_wait,
874 			list_empty(&clnt->cl_tasks), 1*HZ);
875 	}
876 
877 	rpc_release_client(clnt);
878 }
879 EXPORT_SYMBOL_GPL(rpc_shutdown_client);
880 
881 /*
882  * Free an RPC client
883  */
884 static void rpc_free_client_work(struct work_struct *work)
885 {
886 	struct rpc_clnt *clnt = container_of(work, struct rpc_clnt, cl_work);
887 
888 	trace_rpc_clnt_free(clnt);
889 
890 	/* These might block on processes that might allocate memory,
891 	 * so they cannot be called in rpciod, so they are handled separately
892 	 * here.
893 	 */
894 	rpc_sysfs_client_destroy(clnt);
895 	rpc_clnt_debugfs_unregister(clnt);
896 	rpc_free_clid(clnt);
897 	rpc_clnt_remove_pipedir(clnt);
898 	xprt_put(rcu_dereference_raw(clnt->cl_xprt));
899 
900 	kfree(clnt);
901 	rpciod_down();
902 }
903 static struct rpc_clnt *
904 rpc_free_client(struct rpc_clnt *clnt)
905 {
906 	struct rpc_clnt *parent = NULL;
907 
908 	trace_rpc_clnt_release(clnt);
909 	if (clnt->cl_parent != clnt)
910 		parent = clnt->cl_parent;
911 	rpc_unregister_client(clnt);
912 	rpc_free_iostats(clnt->cl_metrics);
913 	clnt->cl_metrics = NULL;
914 	xprt_iter_destroy(&clnt->cl_xpi);
915 	put_cred(clnt->cl_cred);
916 
917 	INIT_WORK(&clnt->cl_work, rpc_free_client_work);
918 	schedule_work(&clnt->cl_work);
919 	return parent;
920 }
921 
922 /*
923  * Free an RPC client
924  */
925 static struct rpc_clnt *
926 rpc_free_auth(struct rpc_clnt *clnt)
927 {
928 	/*
929 	 * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
930 	 *       release remaining GSS contexts. This mechanism ensures
931 	 *       that it can do so safely.
932 	 */
933 	if (clnt->cl_auth != NULL) {
934 		rpcauth_release(clnt->cl_auth);
935 		clnt->cl_auth = NULL;
936 	}
937 	if (refcount_dec_and_test(&clnt->cl_count))
938 		return rpc_free_client(clnt);
939 	return NULL;
940 }
941 
942 /*
943  * Release reference to the RPC client
944  */
945 void
946 rpc_release_client(struct rpc_clnt *clnt)
947 {
948 	do {
949 		if (list_empty(&clnt->cl_tasks))
950 			wake_up(&destroy_wait);
951 		if (refcount_dec_not_one(&clnt->cl_count))
952 			break;
953 		clnt = rpc_free_auth(clnt);
954 	} while (clnt != NULL);
955 }
956 EXPORT_SYMBOL_GPL(rpc_release_client);
957 
958 /**
959  * rpc_bind_new_program - bind a new RPC program to an existing client
960  * @old: old rpc_client
961  * @program: rpc program to set
962  * @vers: rpc program version
963  *
964  * Clones the rpc client and sets up a new RPC program. This is mainly
965  * of use for enabling different RPC programs to share the same transport.
966  * The Sun NFSv2/v3 ACL protocol can do this.
967  */
968 struct rpc_clnt *rpc_bind_new_program(struct rpc_clnt *old,
969 				      const struct rpc_program *program,
970 				      u32 vers)
971 {
972 	struct rpc_create_args args = {
973 		.program	= program,
974 		.prognumber	= program->number,
975 		.version	= vers,
976 		.authflavor	= old->cl_auth->au_flavor,
977 		.cred		= old->cl_cred,
978 	};
979 	struct rpc_clnt *clnt;
980 	int err;
981 
982 	clnt = __rpc_clone_client(&args, old);
983 	if (IS_ERR(clnt))
984 		goto out;
985 	err = rpc_ping(clnt);
986 	if (err != 0) {
987 		rpc_shutdown_client(clnt);
988 		clnt = ERR_PTR(err);
989 	}
990 out:
991 	return clnt;
992 }
993 EXPORT_SYMBOL_GPL(rpc_bind_new_program);
994 
995 struct rpc_xprt *
996 rpc_task_get_xprt(struct rpc_clnt *clnt, struct rpc_xprt *xprt)
997 {
998 	struct rpc_xprt_switch *xps;
999 
1000 	if (!xprt)
1001 		return NULL;
1002 	rcu_read_lock();
1003 	xps = rcu_dereference(clnt->cl_xpi.xpi_xpswitch);
1004 	atomic_long_inc(&xps->xps_queuelen);
1005 	rcu_read_unlock();
1006 	atomic_long_inc(&xprt->queuelen);
1007 
1008 	return xprt;
1009 }
1010 
1011 static void
1012 rpc_task_release_xprt(struct rpc_clnt *clnt, struct rpc_xprt *xprt)
1013 {
1014 	struct rpc_xprt_switch *xps;
1015 
1016 	atomic_long_dec(&xprt->queuelen);
1017 	rcu_read_lock();
1018 	xps = rcu_dereference(clnt->cl_xpi.xpi_xpswitch);
1019 	atomic_long_dec(&xps->xps_queuelen);
1020 	rcu_read_unlock();
1021 
1022 	xprt_put(xprt);
1023 }
1024 
1025 void rpc_task_release_transport(struct rpc_task *task)
1026 {
1027 	struct rpc_xprt *xprt = task->tk_xprt;
1028 
1029 	if (xprt) {
1030 		task->tk_xprt = NULL;
1031 		if (task->tk_client)
1032 			rpc_task_release_xprt(task->tk_client, xprt);
1033 		else
1034 			xprt_put(xprt);
1035 	}
1036 }
1037 EXPORT_SYMBOL_GPL(rpc_task_release_transport);
1038 
1039 void rpc_task_release_client(struct rpc_task *task)
1040 {
1041 	struct rpc_clnt *clnt = task->tk_client;
1042 
1043 	rpc_task_release_transport(task);
1044 	if (clnt != NULL) {
1045 		/* Remove from client task list */
1046 		spin_lock(&clnt->cl_lock);
1047 		list_del(&task->tk_task);
1048 		spin_unlock(&clnt->cl_lock);
1049 		task->tk_client = NULL;
1050 
1051 		rpc_release_client(clnt);
1052 	}
1053 }
1054 
1055 static struct rpc_xprt *
1056 rpc_task_get_first_xprt(struct rpc_clnt *clnt)
1057 {
1058 	struct rpc_xprt *xprt;
1059 
1060 	rcu_read_lock();
1061 	xprt = xprt_get(rcu_dereference(clnt->cl_xprt));
1062 	rcu_read_unlock();
1063 	return rpc_task_get_xprt(clnt, xprt);
1064 }
1065 
1066 static struct rpc_xprt *
1067 rpc_task_get_next_xprt(struct rpc_clnt *clnt)
1068 {
1069 	return rpc_task_get_xprt(clnt, xprt_iter_get_next(&clnt->cl_xpi));
1070 }
1071 
1072 static
1073 void rpc_task_set_transport(struct rpc_task *task, struct rpc_clnt *clnt)
1074 {
1075 	if (task->tk_xprt) {
1076 		if (!(test_bit(XPRT_OFFLINE, &task->tk_xprt->state) &&
1077 		      (task->tk_flags & RPC_TASK_MOVEABLE)))
1078 			return;
1079 		xprt_release(task);
1080 		xprt_put(task->tk_xprt);
1081 	}
1082 	if (task->tk_flags & RPC_TASK_NO_ROUND_ROBIN)
1083 		task->tk_xprt = rpc_task_get_first_xprt(clnt);
1084 	else
1085 		task->tk_xprt = rpc_task_get_next_xprt(clnt);
1086 }
1087 
1088 static
1089 void rpc_task_set_client(struct rpc_task *task, struct rpc_clnt *clnt)
1090 {
1091 	rpc_task_set_transport(task, clnt);
1092 	task->tk_client = clnt;
1093 	refcount_inc(&clnt->cl_count);
1094 	if (clnt->cl_softrtry)
1095 		task->tk_flags |= RPC_TASK_SOFT;
1096 	if (clnt->cl_softerr)
1097 		task->tk_flags |= RPC_TASK_TIMEOUT;
1098 	if (clnt->cl_noretranstimeo)
1099 		task->tk_flags |= RPC_TASK_NO_RETRANS_TIMEOUT;
1100 	/* Add to the client's list of all tasks */
1101 	spin_lock(&clnt->cl_lock);
1102 	list_add_tail(&task->tk_task, &clnt->cl_tasks);
1103 	spin_unlock(&clnt->cl_lock);
1104 }
1105 
1106 static void
1107 rpc_task_set_rpc_message(struct rpc_task *task, const struct rpc_message *msg)
1108 {
1109 	if (msg != NULL) {
1110 		task->tk_msg.rpc_proc = msg->rpc_proc;
1111 		task->tk_msg.rpc_argp = msg->rpc_argp;
1112 		task->tk_msg.rpc_resp = msg->rpc_resp;
1113 		task->tk_msg.rpc_cred = msg->rpc_cred;
1114 		if (!(task->tk_flags & RPC_TASK_CRED_NOREF))
1115 			get_cred(task->tk_msg.rpc_cred);
1116 	}
1117 }
1118 
1119 /*
1120  * Default callback for async RPC calls
1121  */
1122 static void
1123 rpc_default_callback(struct rpc_task *task, void *data)
1124 {
1125 }
1126 
1127 static const struct rpc_call_ops rpc_default_ops = {
1128 	.rpc_call_done = rpc_default_callback,
1129 };
1130 
1131 /**
1132  * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
1133  * @task_setup_data: pointer to task initialisation data
1134  */
1135 struct rpc_task *rpc_run_task(const struct rpc_task_setup *task_setup_data)
1136 {
1137 	struct rpc_task *task;
1138 
1139 	task = rpc_new_task(task_setup_data);
1140 	if (IS_ERR(task))
1141 		return task;
1142 
1143 	if (!RPC_IS_ASYNC(task))
1144 		task->tk_flags |= RPC_TASK_CRED_NOREF;
1145 
1146 	rpc_task_set_client(task, task_setup_data->rpc_client);
1147 	rpc_task_set_rpc_message(task, task_setup_data->rpc_message);
1148 
1149 	if (task->tk_action == NULL)
1150 		rpc_call_start(task);
1151 
1152 	atomic_inc(&task->tk_count);
1153 	rpc_execute(task);
1154 	return task;
1155 }
1156 EXPORT_SYMBOL_GPL(rpc_run_task);
1157 
1158 /**
1159  * rpc_call_sync - Perform a synchronous RPC call
1160  * @clnt: pointer to RPC client
1161  * @msg: RPC call parameters
1162  * @flags: RPC call flags
1163  */
1164 int rpc_call_sync(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags)
1165 {
1166 	struct rpc_task	*task;
1167 	struct rpc_task_setup task_setup_data = {
1168 		.rpc_client = clnt,
1169 		.rpc_message = msg,
1170 		.callback_ops = &rpc_default_ops,
1171 		.flags = flags,
1172 	};
1173 	int status;
1174 
1175 	WARN_ON_ONCE(flags & RPC_TASK_ASYNC);
1176 	if (flags & RPC_TASK_ASYNC) {
1177 		rpc_release_calldata(task_setup_data.callback_ops,
1178 			task_setup_data.callback_data);
1179 		return -EINVAL;
1180 	}
1181 
1182 	task = rpc_run_task(&task_setup_data);
1183 	if (IS_ERR(task))
1184 		return PTR_ERR(task);
1185 	status = task->tk_status;
1186 	rpc_put_task(task);
1187 	return status;
1188 }
1189 EXPORT_SYMBOL_GPL(rpc_call_sync);
1190 
1191 /**
1192  * rpc_call_async - Perform an asynchronous RPC call
1193  * @clnt: pointer to RPC client
1194  * @msg: RPC call parameters
1195  * @flags: RPC call flags
1196  * @tk_ops: RPC call ops
1197  * @data: user call data
1198  */
1199 int
1200 rpc_call_async(struct rpc_clnt *clnt, const struct rpc_message *msg, int flags,
1201 	       const struct rpc_call_ops *tk_ops, void *data)
1202 {
1203 	struct rpc_task	*task;
1204 	struct rpc_task_setup task_setup_data = {
1205 		.rpc_client = clnt,
1206 		.rpc_message = msg,
1207 		.callback_ops = tk_ops,
1208 		.callback_data = data,
1209 		.flags = flags|RPC_TASK_ASYNC,
1210 	};
1211 
1212 	task = rpc_run_task(&task_setup_data);
1213 	if (IS_ERR(task))
1214 		return PTR_ERR(task);
1215 	rpc_put_task(task);
1216 	return 0;
1217 }
1218 EXPORT_SYMBOL_GPL(rpc_call_async);
1219 
1220 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1221 static void call_bc_encode(struct rpc_task *task);
1222 
1223 /**
1224  * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
1225  * rpc_execute against it
1226  * @req: RPC request
1227  */
1228 struct rpc_task *rpc_run_bc_task(struct rpc_rqst *req)
1229 {
1230 	struct rpc_task *task;
1231 	struct rpc_task_setup task_setup_data = {
1232 		.callback_ops = &rpc_default_ops,
1233 		.flags = RPC_TASK_SOFTCONN |
1234 			RPC_TASK_NO_RETRANS_TIMEOUT,
1235 	};
1236 
1237 	dprintk("RPC: rpc_run_bc_task req= %p\n", req);
1238 	/*
1239 	 * Create an rpc_task to send the data
1240 	 */
1241 	task = rpc_new_task(&task_setup_data);
1242 	if (IS_ERR(task)) {
1243 		xprt_free_bc_request(req);
1244 		return task;
1245 	}
1246 
1247 	xprt_init_bc_request(req, task);
1248 
1249 	task->tk_action = call_bc_encode;
1250 	atomic_inc(&task->tk_count);
1251 	WARN_ON_ONCE(atomic_read(&task->tk_count) != 2);
1252 	rpc_execute(task);
1253 
1254 	dprintk("RPC: rpc_run_bc_task: task= %p\n", task);
1255 	return task;
1256 }
1257 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1258 
1259 /**
1260  * rpc_prepare_reply_pages - Prepare to receive a reply data payload into pages
1261  * @req: RPC request to prepare
1262  * @pages: vector of struct page pointers
1263  * @base: offset in first page where receive should start, in bytes
1264  * @len: expected size of the upper layer data payload, in bytes
1265  * @hdrsize: expected size of upper layer reply header, in XDR words
1266  *
1267  */
1268 void rpc_prepare_reply_pages(struct rpc_rqst *req, struct page **pages,
1269 			     unsigned int base, unsigned int len,
1270 			     unsigned int hdrsize)
1271 {
1272 	hdrsize += RPC_REPHDRSIZE + req->rq_cred->cr_auth->au_ralign;
1273 
1274 	xdr_inline_pages(&req->rq_rcv_buf, hdrsize << 2, pages, base, len);
1275 	trace_rpc_xdr_reply_pages(req->rq_task, &req->rq_rcv_buf);
1276 }
1277 EXPORT_SYMBOL_GPL(rpc_prepare_reply_pages);
1278 
1279 void
1280 rpc_call_start(struct rpc_task *task)
1281 {
1282 	task->tk_action = call_start;
1283 }
1284 EXPORT_SYMBOL_GPL(rpc_call_start);
1285 
1286 /**
1287  * rpc_peeraddr - extract remote peer address from clnt's xprt
1288  * @clnt: RPC client structure
1289  * @buf: target buffer
1290  * @bufsize: length of target buffer
1291  *
1292  * Returns the number of bytes that are actually in the stored address.
1293  */
1294 size_t rpc_peeraddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t bufsize)
1295 {
1296 	size_t bytes;
1297 	struct rpc_xprt *xprt;
1298 
1299 	rcu_read_lock();
1300 	xprt = rcu_dereference(clnt->cl_xprt);
1301 
1302 	bytes = xprt->addrlen;
1303 	if (bytes > bufsize)
1304 		bytes = bufsize;
1305 	memcpy(buf, &xprt->addr, bytes);
1306 	rcu_read_unlock();
1307 
1308 	return bytes;
1309 }
1310 EXPORT_SYMBOL_GPL(rpc_peeraddr);
1311 
1312 /**
1313  * rpc_peeraddr2str - return remote peer address in printable format
1314  * @clnt: RPC client structure
1315  * @format: address format
1316  *
1317  * NB: the lifetime of the memory referenced by the returned pointer is
1318  * the same as the rpc_xprt itself.  As long as the caller uses this
1319  * pointer, it must hold the RCU read lock.
1320  */
1321 const char *rpc_peeraddr2str(struct rpc_clnt *clnt,
1322 			     enum rpc_display_format_t format)
1323 {
1324 	struct rpc_xprt *xprt;
1325 
1326 	xprt = rcu_dereference(clnt->cl_xprt);
1327 
1328 	if (xprt->address_strings[format] != NULL)
1329 		return xprt->address_strings[format];
1330 	else
1331 		return "unprintable";
1332 }
1333 EXPORT_SYMBOL_GPL(rpc_peeraddr2str);
1334 
1335 static const struct sockaddr_in rpc_inaddr_loopback = {
1336 	.sin_family		= AF_INET,
1337 	.sin_addr.s_addr	= htonl(INADDR_ANY),
1338 };
1339 
1340 static const struct sockaddr_in6 rpc_in6addr_loopback = {
1341 	.sin6_family		= AF_INET6,
1342 	.sin6_addr		= IN6ADDR_ANY_INIT,
1343 };
1344 
1345 /*
1346  * Try a getsockname() on a connected datagram socket.  Using a
1347  * connected datagram socket prevents leaving a socket in TIME_WAIT.
1348  * This conserves the ephemeral port number space.
1349  *
1350  * Returns zero and fills in "buf" if successful; otherwise, a
1351  * negative errno is returned.
1352  */
1353 static int rpc_sockname(struct net *net, struct sockaddr *sap, size_t salen,
1354 			struct sockaddr *buf)
1355 {
1356 	struct socket *sock;
1357 	int err;
1358 
1359 	err = __sock_create(net, sap->sa_family,
1360 				SOCK_DGRAM, IPPROTO_UDP, &sock, 1);
1361 	if (err < 0) {
1362 		dprintk("RPC:       can't create UDP socket (%d)\n", err);
1363 		goto out;
1364 	}
1365 
1366 	switch (sap->sa_family) {
1367 	case AF_INET:
1368 		err = kernel_bind(sock,
1369 				(struct sockaddr *)&rpc_inaddr_loopback,
1370 				sizeof(rpc_inaddr_loopback));
1371 		break;
1372 	case AF_INET6:
1373 		err = kernel_bind(sock,
1374 				(struct sockaddr *)&rpc_in6addr_loopback,
1375 				sizeof(rpc_in6addr_loopback));
1376 		break;
1377 	default:
1378 		err = -EAFNOSUPPORT;
1379 		goto out;
1380 	}
1381 	if (err < 0) {
1382 		dprintk("RPC:       can't bind UDP socket (%d)\n", err);
1383 		goto out_release;
1384 	}
1385 
1386 	err = kernel_connect(sock, sap, salen, 0);
1387 	if (err < 0) {
1388 		dprintk("RPC:       can't connect UDP socket (%d)\n", err);
1389 		goto out_release;
1390 	}
1391 
1392 	err = kernel_getsockname(sock, buf);
1393 	if (err < 0) {
1394 		dprintk("RPC:       getsockname failed (%d)\n", err);
1395 		goto out_release;
1396 	}
1397 
1398 	err = 0;
1399 	if (buf->sa_family == AF_INET6) {
1400 		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)buf;
1401 		sin6->sin6_scope_id = 0;
1402 	}
1403 	dprintk("RPC:       %s succeeded\n", __func__);
1404 
1405 out_release:
1406 	sock_release(sock);
1407 out:
1408 	return err;
1409 }
1410 
1411 /*
1412  * Scraping a connected socket failed, so we don't have a useable
1413  * local address.  Fallback: generate an address that will prevent
1414  * the server from calling us back.
1415  *
1416  * Returns zero and fills in "buf" if successful; otherwise, a
1417  * negative errno is returned.
1418  */
1419 static int rpc_anyaddr(int family, struct sockaddr *buf, size_t buflen)
1420 {
1421 	switch (family) {
1422 	case AF_INET:
1423 		if (buflen < sizeof(rpc_inaddr_loopback))
1424 			return -EINVAL;
1425 		memcpy(buf, &rpc_inaddr_loopback,
1426 				sizeof(rpc_inaddr_loopback));
1427 		break;
1428 	case AF_INET6:
1429 		if (buflen < sizeof(rpc_in6addr_loopback))
1430 			return -EINVAL;
1431 		memcpy(buf, &rpc_in6addr_loopback,
1432 				sizeof(rpc_in6addr_loopback));
1433 		break;
1434 	default:
1435 		dprintk("RPC:       %s: address family not supported\n",
1436 			__func__);
1437 		return -EAFNOSUPPORT;
1438 	}
1439 	dprintk("RPC:       %s: succeeded\n", __func__);
1440 	return 0;
1441 }
1442 
1443 /**
1444  * rpc_localaddr - discover local endpoint address for an RPC client
1445  * @clnt: RPC client structure
1446  * @buf: target buffer
1447  * @buflen: size of target buffer, in bytes
1448  *
1449  * Returns zero and fills in "buf" and "buflen" if successful;
1450  * otherwise, a negative errno is returned.
1451  *
1452  * This works even if the underlying transport is not currently connected,
1453  * or if the upper layer never previously provided a source address.
1454  *
1455  * The result of this function call is transient: multiple calls in
1456  * succession may give different results, depending on how local
1457  * networking configuration changes over time.
1458  */
1459 int rpc_localaddr(struct rpc_clnt *clnt, struct sockaddr *buf, size_t buflen)
1460 {
1461 	struct sockaddr_storage address;
1462 	struct sockaddr *sap = (struct sockaddr *)&address;
1463 	struct rpc_xprt *xprt;
1464 	struct net *net;
1465 	size_t salen;
1466 	int err;
1467 
1468 	rcu_read_lock();
1469 	xprt = rcu_dereference(clnt->cl_xprt);
1470 	salen = xprt->addrlen;
1471 	memcpy(sap, &xprt->addr, salen);
1472 	net = get_net(xprt->xprt_net);
1473 	rcu_read_unlock();
1474 
1475 	rpc_set_port(sap, 0);
1476 	err = rpc_sockname(net, sap, salen, buf);
1477 	put_net(net);
1478 	if (err != 0)
1479 		/* Couldn't discover local address, return ANYADDR */
1480 		return rpc_anyaddr(sap->sa_family, buf, buflen);
1481 	return 0;
1482 }
1483 EXPORT_SYMBOL_GPL(rpc_localaddr);
1484 
1485 void
1486 rpc_setbufsize(struct rpc_clnt *clnt, unsigned int sndsize, unsigned int rcvsize)
1487 {
1488 	struct rpc_xprt *xprt;
1489 
1490 	rcu_read_lock();
1491 	xprt = rcu_dereference(clnt->cl_xprt);
1492 	if (xprt->ops->set_buffer_size)
1493 		xprt->ops->set_buffer_size(xprt, sndsize, rcvsize);
1494 	rcu_read_unlock();
1495 }
1496 EXPORT_SYMBOL_GPL(rpc_setbufsize);
1497 
1498 /**
1499  * rpc_net_ns - Get the network namespace for this RPC client
1500  * @clnt: RPC client to query
1501  *
1502  */
1503 struct net *rpc_net_ns(struct rpc_clnt *clnt)
1504 {
1505 	struct net *ret;
1506 
1507 	rcu_read_lock();
1508 	ret = rcu_dereference(clnt->cl_xprt)->xprt_net;
1509 	rcu_read_unlock();
1510 	return ret;
1511 }
1512 EXPORT_SYMBOL_GPL(rpc_net_ns);
1513 
1514 /**
1515  * rpc_max_payload - Get maximum payload size for a transport, in bytes
1516  * @clnt: RPC client to query
1517  *
1518  * For stream transports, this is one RPC record fragment (see RFC
1519  * 1831), as we don't support multi-record requests yet.  For datagram
1520  * transports, this is the size of an IP packet minus the IP, UDP, and
1521  * RPC header sizes.
1522  */
1523 size_t rpc_max_payload(struct rpc_clnt *clnt)
1524 {
1525 	size_t ret;
1526 
1527 	rcu_read_lock();
1528 	ret = rcu_dereference(clnt->cl_xprt)->max_payload;
1529 	rcu_read_unlock();
1530 	return ret;
1531 }
1532 EXPORT_SYMBOL_GPL(rpc_max_payload);
1533 
1534 /**
1535  * rpc_max_bc_payload - Get maximum backchannel payload size, in bytes
1536  * @clnt: RPC client to query
1537  */
1538 size_t rpc_max_bc_payload(struct rpc_clnt *clnt)
1539 {
1540 	struct rpc_xprt *xprt;
1541 	size_t ret;
1542 
1543 	rcu_read_lock();
1544 	xprt = rcu_dereference(clnt->cl_xprt);
1545 	ret = xprt->ops->bc_maxpayload(xprt);
1546 	rcu_read_unlock();
1547 	return ret;
1548 }
1549 EXPORT_SYMBOL_GPL(rpc_max_bc_payload);
1550 
1551 unsigned int rpc_num_bc_slots(struct rpc_clnt *clnt)
1552 {
1553 	struct rpc_xprt *xprt;
1554 	unsigned int ret;
1555 
1556 	rcu_read_lock();
1557 	xprt = rcu_dereference(clnt->cl_xprt);
1558 	ret = xprt->ops->bc_num_slots(xprt);
1559 	rcu_read_unlock();
1560 	return ret;
1561 }
1562 EXPORT_SYMBOL_GPL(rpc_num_bc_slots);
1563 
1564 /**
1565  * rpc_force_rebind - force transport to check that remote port is unchanged
1566  * @clnt: client to rebind
1567  *
1568  */
1569 void rpc_force_rebind(struct rpc_clnt *clnt)
1570 {
1571 	if (clnt->cl_autobind) {
1572 		rcu_read_lock();
1573 		xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1574 		rcu_read_unlock();
1575 	}
1576 }
1577 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1578 
1579 static int
1580 __rpc_restart_call(struct rpc_task *task, void (*action)(struct rpc_task *))
1581 {
1582 	task->tk_status = 0;
1583 	task->tk_rpc_status = 0;
1584 	task->tk_action = action;
1585 	return 1;
1586 }
1587 
1588 /*
1589  * Restart an (async) RPC call. Usually called from within the
1590  * exit handler.
1591  */
1592 int
1593 rpc_restart_call(struct rpc_task *task)
1594 {
1595 	return __rpc_restart_call(task, call_start);
1596 }
1597 EXPORT_SYMBOL_GPL(rpc_restart_call);
1598 
1599 /*
1600  * Restart an (async) RPC call from the call_prepare state.
1601  * Usually called from within the exit handler.
1602  */
1603 int
1604 rpc_restart_call_prepare(struct rpc_task *task)
1605 {
1606 	if (task->tk_ops->rpc_call_prepare != NULL)
1607 		return __rpc_restart_call(task, rpc_prepare_task);
1608 	return rpc_restart_call(task);
1609 }
1610 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1611 
1612 const char
1613 *rpc_proc_name(const struct rpc_task *task)
1614 {
1615 	const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1616 
1617 	if (proc) {
1618 		if (proc->p_name)
1619 			return proc->p_name;
1620 		else
1621 			return "NULL";
1622 	} else
1623 		return "no proc";
1624 }
1625 
1626 static void
1627 __rpc_call_rpcerror(struct rpc_task *task, int tk_status, int rpc_status)
1628 {
1629 	trace_rpc_call_rpcerror(task, tk_status, rpc_status);
1630 	task->tk_rpc_status = rpc_status;
1631 	rpc_exit(task, tk_status);
1632 }
1633 
1634 static void
1635 rpc_call_rpcerror(struct rpc_task *task, int status)
1636 {
1637 	__rpc_call_rpcerror(task, status, status);
1638 }
1639 
1640 /*
1641  * 0.  Initial state
1642  *
1643  *     Other FSM states can be visited zero or more times, but
1644  *     this state is visited exactly once for each RPC.
1645  */
1646 static void
1647 call_start(struct rpc_task *task)
1648 {
1649 	struct rpc_clnt	*clnt = task->tk_client;
1650 	int idx = task->tk_msg.rpc_proc->p_statidx;
1651 
1652 	trace_rpc_request(task);
1653 
1654 	/* Increment call count (version might not be valid for ping) */
1655 	if (clnt->cl_program->version[clnt->cl_vers])
1656 		clnt->cl_program->version[clnt->cl_vers]->counts[idx]++;
1657 	clnt->cl_stats->rpccnt++;
1658 	task->tk_action = call_reserve;
1659 	rpc_task_set_transport(task, clnt);
1660 }
1661 
1662 /*
1663  * 1.	Reserve an RPC call slot
1664  */
1665 static void
1666 call_reserve(struct rpc_task *task)
1667 {
1668 	task->tk_status  = 0;
1669 	task->tk_action  = call_reserveresult;
1670 	xprt_reserve(task);
1671 }
1672 
1673 static void call_retry_reserve(struct rpc_task *task);
1674 
1675 /*
1676  * 1b.	Grok the result of xprt_reserve()
1677  */
1678 static void
1679 call_reserveresult(struct rpc_task *task)
1680 {
1681 	int status = task->tk_status;
1682 
1683 	/*
1684 	 * After a call to xprt_reserve(), we must have either
1685 	 * a request slot or else an error status.
1686 	 */
1687 	task->tk_status = 0;
1688 	if (status >= 0) {
1689 		if (task->tk_rqstp) {
1690 			task->tk_action = call_refresh;
1691 			return;
1692 		}
1693 
1694 		rpc_call_rpcerror(task, -EIO);
1695 		return;
1696 	}
1697 
1698 	switch (status) {
1699 	case -ENOMEM:
1700 		rpc_delay(task, HZ >> 2);
1701 		fallthrough;
1702 	case -EAGAIN:	/* woken up; retry */
1703 		task->tk_action = call_retry_reserve;
1704 		return;
1705 	default:
1706 		rpc_call_rpcerror(task, status);
1707 	}
1708 }
1709 
1710 /*
1711  * 1c.	Retry reserving an RPC call slot
1712  */
1713 static void
1714 call_retry_reserve(struct rpc_task *task)
1715 {
1716 	task->tk_status  = 0;
1717 	task->tk_action  = call_reserveresult;
1718 	xprt_retry_reserve(task);
1719 }
1720 
1721 /*
1722  * 2.	Bind and/or refresh the credentials
1723  */
1724 static void
1725 call_refresh(struct rpc_task *task)
1726 {
1727 	task->tk_action = call_refreshresult;
1728 	task->tk_status = 0;
1729 	task->tk_client->cl_stats->rpcauthrefresh++;
1730 	rpcauth_refreshcred(task);
1731 }
1732 
1733 /*
1734  * 2a.	Process the results of a credential refresh
1735  */
1736 static void
1737 call_refreshresult(struct rpc_task *task)
1738 {
1739 	int status = task->tk_status;
1740 
1741 	task->tk_status = 0;
1742 	task->tk_action = call_refresh;
1743 	switch (status) {
1744 	case 0:
1745 		if (rpcauth_uptodatecred(task)) {
1746 			task->tk_action = call_allocate;
1747 			return;
1748 		}
1749 		/* Use rate-limiting and a max number of retries if refresh
1750 		 * had status 0 but failed to update the cred.
1751 		 */
1752 		fallthrough;
1753 	case -ETIMEDOUT:
1754 		rpc_delay(task, 3*HZ);
1755 		fallthrough;
1756 	case -EAGAIN:
1757 		status = -EACCES;
1758 		fallthrough;
1759 	case -EKEYEXPIRED:
1760 		if (!task->tk_cred_retry)
1761 			break;
1762 		task->tk_cred_retry--;
1763 		trace_rpc_retry_refresh_status(task);
1764 		return;
1765 	case -ENOMEM:
1766 		rpc_delay(task, HZ >> 4);
1767 		return;
1768 	}
1769 	trace_rpc_refresh_status(task);
1770 	rpc_call_rpcerror(task, status);
1771 }
1772 
1773 /*
1774  * 2b.	Allocate the buffer. For details, see sched.c:rpc_malloc.
1775  *	(Note: buffer memory is freed in xprt_release).
1776  */
1777 static void
1778 call_allocate(struct rpc_task *task)
1779 {
1780 	const struct rpc_auth *auth = task->tk_rqstp->rq_cred->cr_auth;
1781 	struct rpc_rqst *req = task->tk_rqstp;
1782 	struct rpc_xprt *xprt = req->rq_xprt;
1783 	const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1784 	int status;
1785 
1786 	task->tk_status = 0;
1787 	task->tk_action = call_encode;
1788 
1789 	if (req->rq_buffer)
1790 		return;
1791 
1792 	if (proc->p_proc != 0) {
1793 		BUG_ON(proc->p_arglen == 0);
1794 		if (proc->p_decode != NULL)
1795 			BUG_ON(proc->p_replen == 0);
1796 	}
1797 
1798 	/*
1799 	 * Calculate the size (in quads) of the RPC call
1800 	 * and reply headers, and convert both values
1801 	 * to byte sizes.
1802 	 */
1803 	req->rq_callsize = RPC_CALLHDRSIZE + (auth->au_cslack << 1) +
1804 			   proc->p_arglen;
1805 	req->rq_callsize <<= 2;
1806 	/*
1807 	 * Note: the reply buffer must at minimum allocate enough space
1808 	 * for the 'struct accepted_reply' from RFC5531.
1809 	 */
1810 	req->rq_rcvsize = RPC_REPHDRSIZE + auth->au_rslack + \
1811 			max_t(size_t, proc->p_replen, 2);
1812 	req->rq_rcvsize <<= 2;
1813 
1814 	status = xprt->ops->buf_alloc(task);
1815 	trace_rpc_buf_alloc(task, status);
1816 	if (status == 0)
1817 		return;
1818 	if (status != -ENOMEM) {
1819 		rpc_call_rpcerror(task, status);
1820 		return;
1821 	}
1822 
1823 	if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1824 		task->tk_action = call_allocate;
1825 		rpc_delay(task, HZ>>4);
1826 		return;
1827 	}
1828 
1829 	rpc_call_rpcerror(task, -ERESTARTSYS);
1830 }
1831 
1832 static int
1833 rpc_task_need_encode(struct rpc_task *task)
1834 {
1835 	return test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate) == 0 &&
1836 		(!(task->tk_flags & RPC_TASK_SENT) ||
1837 		 !(task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT) ||
1838 		 xprt_request_need_retransmit(task));
1839 }
1840 
1841 static void
1842 rpc_xdr_encode(struct rpc_task *task)
1843 {
1844 	struct rpc_rqst	*req = task->tk_rqstp;
1845 	struct xdr_stream xdr;
1846 
1847 	xdr_buf_init(&req->rq_snd_buf,
1848 		     req->rq_buffer,
1849 		     req->rq_callsize);
1850 	xdr_buf_init(&req->rq_rcv_buf,
1851 		     req->rq_rbuffer,
1852 		     req->rq_rcvsize);
1853 
1854 	req->rq_reply_bytes_recvd = 0;
1855 	req->rq_snd_buf.head[0].iov_len = 0;
1856 	xdr_init_encode(&xdr, &req->rq_snd_buf,
1857 			req->rq_snd_buf.head[0].iov_base, req);
1858 	xdr_free_bvec(&req->rq_snd_buf);
1859 	if (rpc_encode_header(task, &xdr))
1860 		return;
1861 
1862 	task->tk_status = rpcauth_wrap_req(task, &xdr);
1863 }
1864 
1865 /*
1866  * 3.	Encode arguments of an RPC call
1867  */
1868 static void
1869 call_encode(struct rpc_task *task)
1870 {
1871 	if (!rpc_task_need_encode(task))
1872 		goto out;
1873 
1874 	/* Dequeue task from the receive queue while we're encoding */
1875 	xprt_request_dequeue_xprt(task);
1876 	/* Encode here so that rpcsec_gss can use correct sequence number. */
1877 	rpc_xdr_encode(task);
1878 	/* Add task to reply queue before transmission to avoid races */
1879 	if (task->tk_status == 0 && rpc_reply_expected(task))
1880 		task->tk_status = xprt_request_enqueue_receive(task);
1881 	/* Did the encode result in an error condition? */
1882 	if (task->tk_status != 0) {
1883 		/* Was the error nonfatal? */
1884 		switch (task->tk_status) {
1885 		case -EAGAIN:
1886 		case -ENOMEM:
1887 			rpc_delay(task, HZ >> 4);
1888 			break;
1889 		case -EKEYEXPIRED:
1890 			if (!task->tk_cred_retry) {
1891 				rpc_exit(task, task->tk_status);
1892 			} else {
1893 				task->tk_action = call_refresh;
1894 				task->tk_cred_retry--;
1895 				trace_rpc_retry_refresh_status(task);
1896 			}
1897 			break;
1898 		default:
1899 			rpc_call_rpcerror(task, task->tk_status);
1900 		}
1901 		return;
1902 	}
1903 
1904 	xprt_request_enqueue_transmit(task);
1905 out:
1906 	task->tk_action = call_transmit;
1907 	/* Check that the connection is OK */
1908 	if (!xprt_bound(task->tk_xprt))
1909 		task->tk_action = call_bind;
1910 	else if (!xprt_connected(task->tk_xprt))
1911 		task->tk_action = call_connect;
1912 }
1913 
1914 /*
1915  * Helpers to check if the task was already transmitted, and
1916  * to take action when that is the case.
1917  */
1918 static bool
1919 rpc_task_transmitted(struct rpc_task *task)
1920 {
1921 	return !test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate);
1922 }
1923 
1924 static void
1925 rpc_task_handle_transmitted(struct rpc_task *task)
1926 {
1927 	xprt_end_transmit(task);
1928 	task->tk_action = call_transmit_status;
1929 }
1930 
1931 /*
1932  * 4.	Get the server port number if not yet set
1933  */
1934 static void
1935 call_bind(struct rpc_task *task)
1936 {
1937 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1938 
1939 	if (rpc_task_transmitted(task)) {
1940 		rpc_task_handle_transmitted(task);
1941 		return;
1942 	}
1943 
1944 	if (xprt_bound(xprt)) {
1945 		task->tk_action = call_connect;
1946 		return;
1947 	}
1948 
1949 	task->tk_action = call_bind_status;
1950 	if (!xprt_prepare_transmit(task))
1951 		return;
1952 
1953 	xprt->ops->rpcbind(task);
1954 }
1955 
1956 /*
1957  * 4a.	Sort out bind result
1958  */
1959 static void
1960 call_bind_status(struct rpc_task *task)
1961 {
1962 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1963 	int status = -EIO;
1964 
1965 	if (rpc_task_transmitted(task)) {
1966 		rpc_task_handle_transmitted(task);
1967 		return;
1968 	}
1969 
1970 	if (task->tk_status >= 0)
1971 		goto out_next;
1972 	if (xprt_bound(xprt)) {
1973 		task->tk_status = 0;
1974 		goto out_next;
1975 	}
1976 
1977 	switch (task->tk_status) {
1978 	case -ENOMEM:
1979 		rpc_delay(task, HZ >> 2);
1980 		goto retry_timeout;
1981 	case -EACCES:
1982 		trace_rpcb_prog_unavail_err(task);
1983 		/* fail immediately if this is an RPC ping */
1984 		if (task->tk_msg.rpc_proc->p_proc == 0) {
1985 			status = -EOPNOTSUPP;
1986 			break;
1987 		}
1988 		if (task->tk_rebind_retry == 0)
1989 			break;
1990 		task->tk_rebind_retry--;
1991 		rpc_delay(task, 3*HZ);
1992 		goto retry_timeout;
1993 	case -ENOBUFS:
1994 		rpc_delay(task, HZ >> 2);
1995 		goto retry_timeout;
1996 	case -EAGAIN:
1997 		goto retry_timeout;
1998 	case -ETIMEDOUT:
1999 		trace_rpcb_timeout_err(task);
2000 		goto retry_timeout;
2001 	case -EPFNOSUPPORT:
2002 		/* server doesn't support any rpcbind version we know of */
2003 		trace_rpcb_bind_version_err(task);
2004 		break;
2005 	case -EPROTONOSUPPORT:
2006 		trace_rpcb_bind_version_err(task);
2007 		goto retry_timeout;
2008 	case -ECONNREFUSED:		/* connection problems */
2009 	case -ECONNRESET:
2010 	case -ECONNABORTED:
2011 	case -ENOTCONN:
2012 	case -EHOSTDOWN:
2013 	case -ENETDOWN:
2014 	case -EHOSTUNREACH:
2015 	case -ENETUNREACH:
2016 	case -EPIPE:
2017 		trace_rpcb_unreachable_err(task);
2018 		if (!RPC_IS_SOFTCONN(task)) {
2019 			rpc_delay(task, 5*HZ);
2020 			goto retry_timeout;
2021 		}
2022 		status = task->tk_status;
2023 		break;
2024 	default:
2025 		trace_rpcb_unrecognized_err(task);
2026 	}
2027 
2028 	rpc_call_rpcerror(task, status);
2029 	return;
2030 out_next:
2031 	task->tk_action = call_connect;
2032 	return;
2033 retry_timeout:
2034 	task->tk_status = 0;
2035 	task->tk_action = call_bind;
2036 	rpc_check_timeout(task);
2037 }
2038 
2039 /*
2040  * 4b.	Connect to the RPC server
2041  */
2042 static void
2043 call_connect(struct rpc_task *task)
2044 {
2045 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
2046 
2047 	if (rpc_task_transmitted(task)) {
2048 		rpc_task_handle_transmitted(task);
2049 		return;
2050 	}
2051 
2052 	if (xprt_connected(xprt)) {
2053 		task->tk_action = call_transmit;
2054 		return;
2055 	}
2056 
2057 	task->tk_action = call_connect_status;
2058 	if (task->tk_status < 0)
2059 		return;
2060 	if (task->tk_flags & RPC_TASK_NOCONNECT) {
2061 		rpc_call_rpcerror(task, -ENOTCONN);
2062 		return;
2063 	}
2064 	if (!xprt_prepare_transmit(task))
2065 		return;
2066 	xprt_connect(task);
2067 }
2068 
2069 /*
2070  * 4c.	Sort out connect result
2071  */
2072 static void
2073 call_connect_status(struct rpc_task *task)
2074 {
2075 	struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
2076 	struct rpc_clnt *clnt = task->tk_client;
2077 	int status = task->tk_status;
2078 
2079 	if (rpc_task_transmitted(task)) {
2080 		rpc_task_handle_transmitted(task);
2081 		return;
2082 	}
2083 
2084 	trace_rpc_connect_status(task);
2085 
2086 	if (task->tk_status == 0) {
2087 		clnt->cl_stats->netreconn++;
2088 		goto out_next;
2089 	}
2090 	if (xprt_connected(xprt)) {
2091 		task->tk_status = 0;
2092 		goto out_next;
2093 	}
2094 
2095 	task->tk_status = 0;
2096 	switch (status) {
2097 	case -ECONNREFUSED:
2098 		/* A positive refusal suggests a rebind is needed. */
2099 		if (RPC_IS_SOFTCONN(task))
2100 			break;
2101 		if (clnt->cl_autobind) {
2102 			rpc_force_rebind(clnt);
2103 			goto out_retry;
2104 		}
2105 		fallthrough;
2106 	case -ECONNRESET:
2107 	case -ECONNABORTED:
2108 	case -ENETDOWN:
2109 	case -ENETUNREACH:
2110 	case -EHOSTUNREACH:
2111 	case -EPIPE:
2112 	case -EPROTO:
2113 		xprt_conditional_disconnect(task->tk_rqstp->rq_xprt,
2114 					    task->tk_rqstp->rq_connect_cookie);
2115 		if (RPC_IS_SOFTCONN(task))
2116 			break;
2117 		/* retry with existing socket, after a delay */
2118 		rpc_delay(task, 3*HZ);
2119 		fallthrough;
2120 	case -EADDRINUSE:
2121 	case -ENOTCONN:
2122 	case -EAGAIN:
2123 	case -ETIMEDOUT:
2124 		if (!(task->tk_flags & RPC_TASK_NO_ROUND_ROBIN) &&
2125 		    (task->tk_flags & RPC_TASK_MOVEABLE) &&
2126 		    test_bit(XPRT_REMOVE, &xprt->state)) {
2127 			struct rpc_xprt *saved = task->tk_xprt;
2128 			struct rpc_xprt_switch *xps;
2129 
2130 			rcu_read_lock();
2131 			xps = xprt_switch_get(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
2132 			rcu_read_unlock();
2133 			if (xps->xps_nxprts > 1) {
2134 				long value;
2135 
2136 				xprt_release(task);
2137 				value = atomic_long_dec_return(&xprt->queuelen);
2138 				if (value == 0)
2139 					rpc_xprt_switch_remove_xprt(xps, saved);
2140 				xprt_put(saved);
2141 				task->tk_xprt = NULL;
2142 				task->tk_action = call_start;
2143 			}
2144 			xprt_switch_put(xps);
2145 			if (!task->tk_xprt)
2146 				return;
2147 		}
2148 		goto out_retry;
2149 	case -ENOBUFS:
2150 		rpc_delay(task, HZ >> 2);
2151 		goto out_retry;
2152 	}
2153 	rpc_call_rpcerror(task, status);
2154 	return;
2155 out_next:
2156 	task->tk_action = call_transmit;
2157 	return;
2158 out_retry:
2159 	/* Check for timeouts before looping back to call_bind */
2160 	task->tk_action = call_bind;
2161 	rpc_check_timeout(task);
2162 }
2163 
2164 /*
2165  * 5.	Transmit the RPC request, and wait for reply
2166  */
2167 static void
2168 call_transmit(struct rpc_task *task)
2169 {
2170 	if (rpc_task_transmitted(task)) {
2171 		rpc_task_handle_transmitted(task);
2172 		return;
2173 	}
2174 
2175 	task->tk_action = call_transmit_status;
2176 	if (!xprt_prepare_transmit(task))
2177 		return;
2178 	task->tk_status = 0;
2179 	if (test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate)) {
2180 		if (!xprt_connected(task->tk_xprt)) {
2181 			task->tk_status = -ENOTCONN;
2182 			return;
2183 		}
2184 		xprt_transmit(task);
2185 	}
2186 	xprt_end_transmit(task);
2187 }
2188 
2189 /*
2190  * 5a.	Handle cleanup after a transmission
2191  */
2192 static void
2193 call_transmit_status(struct rpc_task *task)
2194 {
2195 	task->tk_action = call_status;
2196 
2197 	/*
2198 	 * Common case: success.  Force the compiler to put this
2199 	 * test first.
2200 	 */
2201 	if (rpc_task_transmitted(task)) {
2202 		task->tk_status = 0;
2203 		xprt_request_wait_receive(task);
2204 		return;
2205 	}
2206 
2207 	switch (task->tk_status) {
2208 	default:
2209 		break;
2210 	case -EBADMSG:
2211 		task->tk_status = 0;
2212 		task->tk_action = call_encode;
2213 		break;
2214 		/*
2215 		 * Special cases: if we've been waiting on the
2216 		 * socket's write_space() callback, or if the
2217 		 * socket just returned a connection error,
2218 		 * then hold onto the transport lock.
2219 		 */
2220 	case -ENOMEM:
2221 	case -ENOBUFS:
2222 		rpc_delay(task, HZ>>2);
2223 		fallthrough;
2224 	case -EBADSLT:
2225 	case -EAGAIN:
2226 		task->tk_action = call_transmit;
2227 		task->tk_status = 0;
2228 		break;
2229 	case -ECONNREFUSED:
2230 	case -EHOSTDOWN:
2231 	case -ENETDOWN:
2232 	case -EHOSTUNREACH:
2233 	case -ENETUNREACH:
2234 	case -EPERM:
2235 		if (RPC_IS_SOFTCONN(task)) {
2236 			if (!task->tk_msg.rpc_proc->p_proc)
2237 				trace_xprt_ping(task->tk_xprt,
2238 						task->tk_status);
2239 			rpc_call_rpcerror(task, task->tk_status);
2240 			return;
2241 		}
2242 		fallthrough;
2243 	case -ECONNRESET:
2244 	case -ECONNABORTED:
2245 	case -EADDRINUSE:
2246 	case -ENOTCONN:
2247 	case -EPIPE:
2248 		task->tk_action = call_bind;
2249 		task->tk_status = 0;
2250 		break;
2251 	}
2252 	rpc_check_timeout(task);
2253 }
2254 
2255 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
2256 static void call_bc_transmit(struct rpc_task *task);
2257 static void call_bc_transmit_status(struct rpc_task *task);
2258 
2259 static void
2260 call_bc_encode(struct rpc_task *task)
2261 {
2262 	xprt_request_enqueue_transmit(task);
2263 	task->tk_action = call_bc_transmit;
2264 }
2265 
2266 /*
2267  * 5b.	Send the backchannel RPC reply.  On error, drop the reply.  In
2268  * addition, disconnect on connectivity errors.
2269  */
2270 static void
2271 call_bc_transmit(struct rpc_task *task)
2272 {
2273 	task->tk_action = call_bc_transmit_status;
2274 	if (test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate)) {
2275 		if (!xprt_prepare_transmit(task))
2276 			return;
2277 		task->tk_status = 0;
2278 		xprt_transmit(task);
2279 	}
2280 	xprt_end_transmit(task);
2281 }
2282 
2283 static void
2284 call_bc_transmit_status(struct rpc_task *task)
2285 {
2286 	struct rpc_rqst *req = task->tk_rqstp;
2287 
2288 	if (rpc_task_transmitted(task))
2289 		task->tk_status = 0;
2290 
2291 	switch (task->tk_status) {
2292 	case 0:
2293 		/* Success */
2294 	case -ENETDOWN:
2295 	case -EHOSTDOWN:
2296 	case -EHOSTUNREACH:
2297 	case -ENETUNREACH:
2298 	case -ECONNRESET:
2299 	case -ECONNREFUSED:
2300 	case -EADDRINUSE:
2301 	case -ENOTCONN:
2302 	case -EPIPE:
2303 		break;
2304 	case -ENOMEM:
2305 	case -ENOBUFS:
2306 		rpc_delay(task, HZ>>2);
2307 		fallthrough;
2308 	case -EBADSLT:
2309 	case -EAGAIN:
2310 		task->tk_status = 0;
2311 		task->tk_action = call_bc_transmit;
2312 		return;
2313 	case -ETIMEDOUT:
2314 		/*
2315 		 * Problem reaching the server.  Disconnect and let the
2316 		 * forechannel reestablish the connection.  The server will
2317 		 * have to retransmit the backchannel request and we'll
2318 		 * reprocess it.  Since these ops are idempotent, there's no
2319 		 * need to cache our reply at this time.
2320 		 */
2321 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
2322 			"error: %d\n", task->tk_status);
2323 		xprt_conditional_disconnect(req->rq_xprt,
2324 			req->rq_connect_cookie);
2325 		break;
2326 	default:
2327 		/*
2328 		 * We were unable to reply and will have to drop the
2329 		 * request.  The server should reconnect and retransmit.
2330 		 */
2331 		printk(KERN_NOTICE "RPC: Could not send backchannel reply "
2332 			"error: %d\n", task->tk_status);
2333 		break;
2334 	}
2335 	task->tk_action = rpc_exit_task;
2336 }
2337 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
2338 
2339 /*
2340  * 6.	Sort out the RPC call status
2341  */
2342 static void
2343 call_status(struct rpc_task *task)
2344 {
2345 	struct rpc_clnt	*clnt = task->tk_client;
2346 	int		status;
2347 
2348 	if (!task->tk_msg.rpc_proc->p_proc)
2349 		trace_xprt_ping(task->tk_xprt, task->tk_status);
2350 
2351 	status = task->tk_status;
2352 	if (status >= 0) {
2353 		task->tk_action = call_decode;
2354 		return;
2355 	}
2356 
2357 	trace_rpc_call_status(task);
2358 	task->tk_status = 0;
2359 	switch(status) {
2360 	case -EHOSTDOWN:
2361 	case -ENETDOWN:
2362 	case -EHOSTUNREACH:
2363 	case -ENETUNREACH:
2364 	case -EPERM:
2365 		if (RPC_IS_SOFTCONN(task))
2366 			goto out_exit;
2367 		/*
2368 		 * Delay any retries for 3 seconds, then handle as if it
2369 		 * were a timeout.
2370 		 */
2371 		rpc_delay(task, 3*HZ);
2372 		fallthrough;
2373 	case -ETIMEDOUT:
2374 		break;
2375 	case -ECONNREFUSED:
2376 	case -ECONNRESET:
2377 	case -ECONNABORTED:
2378 	case -ENOTCONN:
2379 		rpc_force_rebind(clnt);
2380 		break;
2381 	case -EADDRINUSE:
2382 		rpc_delay(task, 3*HZ);
2383 		fallthrough;
2384 	case -EPIPE:
2385 	case -EAGAIN:
2386 		break;
2387 	case -ENFILE:
2388 	case -ENOBUFS:
2389 	case -ENOMEM:
2390 		rpc_delay(task, HZ>>2);
2391 		break;
2392 	case -EIO:
2393 		/* shutdown or soft timeout */
2394 		goto out_exit;
2395 	default:
2396 		if (clnt->cl_chatty)
2397 			printk("%s: RPC call returned error %d\n",
2398 			       clnt->cl_program->name, -status);
2399 		goto out_exit;
2400 	}
2401 	task->tk_action = call_encode;
2402 	if (status != -ECONNRESET && status != -ECONNABORTED)
2403 		rpc_check_timeout(task);
2404 	return;
2405 out_exit:
2406 	rpc_call_rpcerror(task, status);
2407 }
2408 
2409 static bool
2410 rpc_check_connected(const struct rpc_rqst *req)
2411 {
2412 	/* No allocated request or transport? return true */
2413 	if (!req || !req->rq_xprt)
2414 		return true;
2415 	return xprt_connected(req->rq_xprt);
2416 }
2417 
2418 static void
2419 rpc_check_timeout(struct rpc_task *task)
2420 {
2421 	struct rpc_clnt	*clnt = task->tk_client;
2422 
2423 	if (RPC_SIGNALLED(task)) {
2424 		rpc_call_rpcerror(task, -ERESTARTSYS);
2425 		return;
2426 	}
2427 
2428 	if (xprt_adjust_timeout(task->tk_rqstp) == 0)
2429 		return;
2430 
2431 	trace_rpc_timeout_status(task);
2432 	task->tk_timeouts++;
2433 
2434 	if (RPC_IS_SOFTCONN(task) && !rpc_check_connected(task->tk_rqstp)) {
2435 		rpc_call_rpcerror(task, -ETIMEDOUT);
2436 		return;
2437 	}
2438 
2439 	if (RPC_IS_SOFT(task)) {
2440 		/*
2441 		 * Once a "no retrans timeout" soft tasks (a.k.a NFSv4) has
2442 		 * been sent, it should time out only if the transport
2443 		 * connection gets terminally broken.
2444 		 */
2445 		if ((task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT) &&
2446 		    rpc_check_connected(task->tk_rqstp))
2447 			return;
2448 
2449 		if (clnt->cl_chatty) {
2450 			pr_notice_ratelimited(
2451 				"%s: server %s not responding, timed out\n",
2452 				clnt->cl_program->name,
2453 				task->tk_xprt->servername);
2454 		}
2455 		if (task->tk_flags & RPC_TASK_TIMEOUT)
2456 			rpc_call_rpcerror(task, -ETIMEDOUT);
2457 		else
2458 			__rpc_call_rpcerror(task, -EIO, -ETIMEDOUT);
2459 		return;
2460 	}
2461 
2462 	if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
2463 		task->tk_flags |= RPC_CALL_MAJORSEEN;
2464 		if (clnt->cl_chatty) {
2465 			pr_notice_ratelimited(
2466 				"%s: server %s not responding, still trying\n",
2467 				clnt->cl_program->name,
2468 				task->tk_xprt->servername);
2469 		}
2470 	}
2471 	rpc_force_rebind(clnt);
2472 	/*
2473 	 * Did our request time out due to an RPCSEC_GSS out-of-sequence
2474 	 * event? RFC2203 requires the server to drop all such requests.
2475 	 */
2476 	rpcauth_invalcred(task);
2477 }
2478 
2479 /*
2480  * 7.	Decode the RPC reply
2481  */
2482 static void
2483 call_decode(struct rpc_task *task)
2484 {
2485 	struct rpc_clnt	*clnt = task->tk_client;
2486 	struct rpc_rqst	*req = task->tk_rqstp;
2487 	struct xdr_stream xdr;
2488 	int err;
2489 
2490 	if (!task->tk_msg.rpc_proc->p_decode) {
2491 		task->tk_action = rpc_exit_task;
2492 		return;
2493 	}
2494 
2495 	if (task->tk_flags & RPC_CALL_MAJORSEEN) {
2496 		if (clnt->cl_chatty) {
2497 			pr_notice_ratelimited("%s: server %s OK\n",
2498 				clnt->cl_program->name,
2499 				task->tk_xprt->servername);
2500 		}
2501 		task->tk_flags &= ~RPC_CALL_MAJORSEEN;
2502 	}
2503 
2504 	/*
2505 	 * Did we ever call xprt_complete_rqst()? If not, we should assume
2506 	 * the message is incomplete.
2507 	 */
2508 	err = -EAGAIN;
2509 	if (!req->rq_reply_bytes_recvd)
2510 		goto out;
2511 
2512 	/* Ensure that we see all writes made by xprt_complete_rqst()
2513 	 * before it changed req->rq_reply_bytes_recvd.
2514 	 */
2515 	smp_rmb();
2516 
2517 	req->rq_rcv_buf.len = req->rq_private_buf.len;
2518 	trace_rpc_xdr_recvfrom(task, &req->rq_rcv_buf);
2519 
2520 	/* Check that the softirq receive buffer is valid */
2521 	WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
2522 				sizeof(req->rq_rcv_buf)) != 0);
2523 
2524 	xdr_init_decode(&xdr, &req->rq_rcv_buf,
2525 			req->rq_rcv_buf.head[0].iov_base, req);
2526 	err = rpc_decode_header(task, &xdr);
2527 out:
2528 	switch (err) {
2529 	case 0:
2530 		task->tk_action = rpc_exit_task;
2531 		task->tk_status = rpcauth_unwrap_resp(task, &xdr);
2532 		return;
2533 	case -EAGAIN:
2534 		task->tk_status = 0;
2535 		if (task->tk_client->cl_discrtry)
2536 			xprt_conditional_disconnect(req->rq_xprt,
2537 						    req->rq_connect_cookie);
2538 		task->tk_action = call_encode;
2539 		rpc_check_timeout(task);
2540 		break;
2541 	case -EKEYREJECTED:
2542 		task->tk_action = call_reserve;
2543 		rpc_check_timeout(task);
2544 		rpcauth_invalcred(task);
2545 		/* Ensure we obtain a new XID if we retry! */
2546 		xprt_release(task);
2547 	}
2548 }
2549 
2550 static int
2551 rpc_encode_header(struct rpc_task *task, struct xdr_stream *xdr)
2552 {
2553 	struct rpc_clnt *clnt = task->tk_client;
2554 	struct rpc_rqst	*req = task->tk_rqstp;
2555 	__be32 *p;
2556 	int error;
2557 
2558 	error = -EMSGSIZE;
2559 	p = xdr_reserve_space(xdr, RPC_CALLHDRSIZE << 2);
2560 	if (!p)
2561 		goto out_fail;
2562 	*p++ = req->rq_xid;
2563 	*p++ = rpc_call;
2564 	*p++ = cpu_to_be32(RPC_VERSION);
2565 	*p++ = cpu_to_be32(clnt->cl_prog);
2566 	*p++ = cpu_to_be32(clnt->cl_vers);
2567 	*p   = cpu_to_be32(task->tk_msg.rpc_proc->p_proc);
2568 
2569 	error = rpcauth_marshcred(task, xdr);
2570 	if (error < 0)
2571 		goto out_fail;
2572 	return 0;
2573 out_fail:
2574 	trace_rpc_bad_callhdr(task);
2575 	rpc_call_rpcerror(task, error);
2576 	return error;
2577 }
2578 
2579 static noinline int
2580 rpc_decode_header(struct rpc_task *task, struct xdr_stream *xdr)
2581 {
2582 	struct rpc_clnt *clnt = task->tk_client;
2583 	int error;
2584 	__be32 *p;
2585 
2586 	/* RFC-1014 says that the representation of XDR data must be a
2587 	 * multiple of four bytes
2588 	 * - if it isn't pointer subtraction in the NFS client may give
2589 	 *   undefined results
2590 	 */
2591 	if (task->tk_rqstp->rq_rcv_buf.len & 3)
2592 		goto out_unparsable;
2593 
2594 	p = xdr_inline_decode(xdr, 3 * sizeof(*p));
2595 	if (!p)
2596 		goto out_unparsable;
2597 	p++;	/* skip XID */
2598 	if (*p++ != rpc_reply)
2599 		goto out_unparsable;
2600 	if (*p++ != rpc_msg_accepted)
2601 		goto out_msg_denied;
2602 
2603 	error = rpcauth_checkverf(task, xdr);
2604 	if (error)
2605 		goto out_verifier;
2606 
2607 	p = xdr_inline_decode(xdr, sizeof(*p));
2608 	if (!p)
2609 		goto out_unparsable;
2610 	switch (*p) {
2611 	case rpc_success:
2612 		return 0;
2613 	case rpc_prog_unavail:
2614 		trace_rpc__prog_unavail(task);
2615 		error = -EPFNOSUPPORT;
2616 		goto out_err;
2617 	case rpc_prog_mismatch:
2618 		trace_rpc__prog_mismatch(task);
2619 		error = -EPROTONOSUPPORT;
2620 		goto out_err;
2621 	case rpc_proc_unavail:
2622 		trace_rpc__proc_unavail(task);
2623 		error = -EOPNOTSUPP;
2624 		goto out_err;
2625 	case rpc_garbage_args:
2626 	case rpc_system_err:
2627 		trace_rpc__garbage_args(task);
2628 		error = -EIO;
2629 		break;
2630 	default:
2631 		goto out_unparsable;
2632 	}
2633 
2634 out_garbage:
2635 	clnt->cl_stats->rpcgarbage++;
2636 	if (task->tk_garb_retry) {
2637 		task->tk_garb_retry--;
2638 		task->tk_action = call_encode;
2639 		return -EAGAIN;
2640 	}
2641 out_err:
2642 	rpc_call_rpcerror(task, error);
2643 	return error;
2644 
2645 out_unparsable:
2646 	trace_rpc__unparsable(task);
2647 	error = -EIO;
2648 	goto out_garbage;
2649 
2650 out_verifier:
2651 	trace_rpc_bad_verifier(task);
2652 	goto out_garbage;
2653 
2654 out_msg_denied:
2655 	error = -EACCES;
2656 	p = xdr_inline_decode(xdr, sizeof(*p));
2657 	if (!p)
2658 		goto out_unparsable;
2659 	switch (*p++) {
2660 	case rpc_auth_error:
2661 		break;
2662 	case rpc_mismatch:
2663 		trace_rpc__mismatch(task);
2664 		error = -EPROTONOSUPPORT;
2665 		goto out_err;
2666 	default:
2667 		goto out_unparsable;
2668 	}
2669 
2670 	p = xdr_inline_decode(xdr, sizeof(*p));
2671 	if (!p)
2672 		goto out_unparsable;
2673 	switch (*p++) {
2674 	case rpc_autherr_rejectedcred:
2675 	case rpc_autherr_rejectedverf:
2676 	case rpcsec_gsserr_credproblem:
2677 	case rpcsec_gsserr_ctxproblem:
2678 		if (!task->tk_cred_retry)
2679 			break;
2680 		task->tk_cred_retry--;
2681 		trace_rpc__stale_creds(task);
2682 		return -EKEYREJECTED;
2683 	case rpc_autherr_badcred:
2684 	case rpc_autherr_badverf:
2685 		/* possibly garbled cred/verf? */
2686 		if (!task->tk_garb_retry)
2687 			break;
2688 		task->tk_garb_retry--;
2689 		trace_rpc__bad_creds(task);
2690 		task->tk_action = call_encode;
2691 		return -EAGAIN;
2692 	case rpc_autherr_tooweak:
2693 		trace_rpc__auth_tooweak(task);
2694 		pr_warn("RPC: server %s requires stronger authentication.\n",
2695 			task->tk_xprt->servername);
2696 		break;
2697 	default:
2698 		goto out_unparsable;
2699 	}
2700 	goto out_err;
2701 }
2702 
2703 static void rpcproc_encode_null(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
2704 		const void *obj)
2705 {
2706 }
2707 
2708 static int rpcproc_decode_null(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
2709 		void *obj)
2710 {
2711 	return 0;
2712 }
2713 
2714 static const struct rpc_procinfo rpcproc_null = {
2715 	.p_encode = rpcproc_encode_null,
2716 	.p_decode = rpcproc_decode_null,
2717 };
2718 
2719 static const struct rpc_procinfo rpcproc_null_noreply = {
2720 	.p_encode = rpcproc_encode_null,
2721 };
2722 
2723 static void
2724 rpc_null_call_prepare(struct rpc_task *task, void *data)
2725 {
2726 	task->tk_flags &= ~RPC_TASK_NO_RETRANS_TIMEOUT;
2727 	rpc_call_start(task);
2728 }
2729 
2730 static const struct rpc_call_ops rpc_null_ops = {
2731 	.rpc_call_prepare = rpc_null_call_prepare,
2732 	.rpc_call_done = rpc_default_callback,
2733 };
2734 
2735 static
2736 struct rpc_task *rpc_call_null_helper(struct rpc_clnt *clnt,
2737 		struct rpc_xprt *xprt, struct rpc_cred *cred, int flags,
2738 		const struct rpc_call_ops *ops, void *data)
2739 {
2740 	struct rpc_message msg = {
2741 		.rpc_proc = &rpcproc_null,
2742 	};
2743 	struct rpc_task_setup task_setup_data = {
2744 		.rpc_client = clnt,
2745 		.rpc_xprt = xprt,
2746 		.rpc_message = &msg,
2747 		.rpc_op_cred = cred,
2748 		.callback_ops = ops ?: &rpc_null_ops,
2749 		.callback_data = data,
2750 		.flags = flags | RPC_TASK_SOFT | RPC_TASK_SOFTCONN |
2751 			 RPC_TASK_NULLCREDS,
2752 	};
2753 
2754 	return rpc_run_task(&task_setup_data);
2755 }
2756 
2757 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2758 {
2759 	return rpc_call_null_helper(clnt, NULL, cred, flags, NULL, NULL);
2760 }
2761 EXPORT_SYMBOL_GPL(rpc_call_null);
2762 
2763 static int rpc_ping(struct rpc_clnt *clnt)
2764 {
2765 	struct rpc_task	*task;
2766 	int status;
2767 
2768 	task = rpc_call_null_helper(clnt, NULL, NULL, 0, NULL, NULL);
2769 	if (IS_ERR(task))
2770 		return PTR_ERR(task);
2771 	status = task->tk_status;
2772 	rpc_put_task(task);
2773 	return status;
2774 }
2775 
2776 static int rpc_ping_noreply(struct rpc_clnt *clnt)
2777 {
2778 	struct rpc_message msg = {
2779 		.rpc_proc = &rpcproc_null_noreply,
2780 	};
2781 	struct rpc_task_setup task_setup_data = {
2782 		.rpc_client = clnt,
2783 		.rpc_message = &msg,
2784 		.callback_ops = &rpc_null_ops,
2785 		.flags = RPC_TASK_SOFT | RPC_TASK_SOFTCONN | RPC_TASK_NULLCREDS,
2786 	};
2787 	struct rpc_task	*task;
2788 	int status;
2789 
2790 	task = rpc_run_task(&task_setup_data);
2791 	if (IS_ERR(task))
2792 		return PTR_ERR(task);
2793 	status = task->tk_status;
2794 	rpc_put_task(task);
2795 	return status;
2796 }
2797 
2798 struct rpc_cb_add_xprt_calldata {
2799 	struct rpc_xprt_switch *xps;
2800 	struct rpc_xprt *xprt;
2801 };
2802 
2803 static void rpc_cb_add_xprt_done(struct rpc_task *task, void *calldata)
2804 {
2805 	struct rpc_cb_add_xprt_calldata *data = calldata;
2806 
2807 	if (task->tk_status == 0)
2808 		rpc_xprt_switch_add_xprt(data->xps, data->xprt);
2809 }
2810 
2811 static void rpc_cb_add_xprt_release(void *calldata)
2812 {
2813 	struct rpc_cb_add_xprt_calldata *data = calldata;
2814 
2815 	xprt_put(data->xprt);
2816 	xprt_switch_put(data->xps);
2817 	kfree(data);
2818 }
2819 
2820 static const struct rpc_call_ops rpc_cb_add_xprt_call_ops = {
2821 	.rpc_call_prepare = rpc_null_call_prepare,
2822 	.rpc_call_done = rpc_cb_add_xprt_done,
2823 	.rpc_release = rpc_cb_add_xprt_release,
2824 };
2825 
2826 /**
2827  * rpc_clnt_test_and_add_xprt - Test and add a new transport to a rpc_clnt
2828  * @clnt: pointer to struct rpc_clnt
2829  * @xps: pointer to struct rpc_xprt_switch,
2830  * @xprt: pointer struct rpc_xprt
2831  * @dummy: unused
2832  */
2833 int rpc_clnt_test_and_add_xprt(struct rpc_clnt *clnt,
2834 		struct rpc_xprt_switch *xps, struct rpc_xprt *xprt,
2835 		void *dummy)
2836 {
2837 	struct rpc_cb_add_xprt_calldata *data;
2838 	struct rpc_task *task;
2839 
2840 	if (xps->xps_nunique_destaddr_xprts + 1 > clnt->cl_max_connect) {
2841 		rcu_read_lock();
2842 		pr_warn("SUNRPC: reached max allowed number (%d) did not add "
2843 			"transport to server: %s\n", clnt->cl_max_connect,
2844 			rpc_peeraddr2str(clnt, RPC_DISPLAY_ADDR));
2845 		rcu_read_unlock();
2846 		return -EINVAL;
2847 	}
2848 
2849 	data = kmalloc(sizeof(*data), GFP_KERNEL);
2850 	if (!data)
2851 		return -ENOMEM;
2852 	data->xps = xprt_switch_get(xps);
2853 	data->xprt = xprt_get(xprt);
2854 	if (rpc_xprt_switch_has_addr(data->xps, (struct sockaddr *)&xprt->addr)) {
2855 		rpc_cb_add_xprt_release(data);
2856 		goto success;
2857 	}
2858 
2859 	task = rpc_call_null_helper(clnt, xprt, NULL, RPC_TASK_ASYNC,
2860 			&rpc_cb_add_xprt_call_ops, data);
2861 	data->xps->xps_nunique_destaddr_xprts++;
2862 	rpc_put_task(task);
2863 success:
2864 	return 1;
2865 }
2866 EXPORT_SYMBOL_GPL(rpc_clnt_test_and_add_xprt);
2867 
2868 /**
2869  * rpc_clnt_setup_test_and_add_xprt()
2870  *
2871  * This is an rpc_clnt_add_xprt setup() function which returns 1 so:
2872  *   1) caller of the test function must dereference the rpc_xprt_switch
2873  *   and the rpc_xprt.
2874  *   2) test function must call rpc_xprt_switch_add_xprt, usually in
2875  *   the rpc_call_done routine.
2876  *
2877  * Upon success (return of 1), the test function adds the new
2878  * transport to the rpc_clnt xprt switch
2879  *
2880  * @clnt: struct rpc_clnt to get the new transport
2881  * @xps:  the rpc_xprt_switch to hold the new transport
2882  * @xprt: the rpc_xprt to test
2883  * @data: a struct rpc_add_xprt_test pointer that holds the test function
2884  *        and test function call data
2885  */
2886 int rpc_clnt_setup_test_and_add_xprt(struct rpc_clnt *clnt,
2887 				     struct rpc_xprt_switch *xps,
2888 				     struct rpc_xprt *xprt,
2889 				     void *data)
2890 {
2891 	struct rpc_task *task;
2892 	struct rpc_add_xprt_test *xtest = (struct rpc_add_xprt_test *)data;
2893 	int status = -EADDRINUSE;
2894 
2895 	xprt = xprt_get(xprt);
2896 	xprt_switch_get(xps);
2897 
2898 	if (rpc_xprt_switch_has_addr(xps, (struct sockaddr *)&xprt->addr))
2899 		goto out_err;
2900 
2901 	/* Test the connection */
2902 	task = rpc_call_null_helper(clnt, xprt, NULL, 0, NULL, NULL);
2903 	if (IS_ERR(task)) {
2904 		status = PTR_ERR(task);
2905 		goto out_err;
2906 	}
2907 	status = task->tk_status;
2908 	rpc_put_task(task);
2909 
2910 	if (status < 0)
2911 		goto out_err;
2912 
2913 	/* rpc_xprt_switch and rpc_xprt are deferrenced by add_xprt_test() */
2914 	xtest->add_xprt_test(clnt, xprt, xtest->data);
2915 
2916 	xprt_put(xprt);
2917 	xprt_switch_put(xps);
2918 
2919 	/* so that rpc_clnt_add_xprt does not call rpc_xprt_switch_add_xprt */
2920 	return 1;
2921 out_err:
2922 	xprt_put(xprt);
2923 	xprt_switch_put(xps);
2924 	pr_info("RPC:   rpc_clnt_test_xprt failed: %d addr %s not added\n",
2925 		status, xprt->address_strings[RPC_DISPLAY_ADDR]);
2926 	return status;
2927 }
2928 EXPORT_SYMBOL_GPL(rpc_clnt_setup_test_and_add_xprt);
2929 
2930 /**
2931  * rpc_clnt_add_xprt - Add a new transport to a rpc_clnt
2932  * @clnt: pointer to struct rpc_clnt
2933  * @xprtargs: pointer to struct xprt_create
2934  * @setup: callback to test and/or set up the connection
2935  * @data: pointer to setup function data
2936  *
2937  * Creates a new transport using the parameters set in args and
2938  * adds it to clnt.
2939  * If ping is set, then test that connectivity succeeds before
2940  * adding the new transport.
2941  *
2942  */
2943 int rpc_clnt_add_xprt(struct rpc_clnt *clnt,
2944 		struct xprt_create *xprtargs,
2945 		int (*setup)(struct rpc_clnt *,
2946 			struct rpc_xprt_switch *,
2947 			struct rpc_xprt *,
2948 			void *),
2949 		void *data)
2950 {
2951 	struct rpc_xprt_switch *xps;
2952 	struct rpc_xprt *xprt;
2953 	unsigned long connect_timeout;
2954 	unsigned long reconnect_timeout;
2955 	unsigned char resvport, reuseport;
2956 	int ret = 0, ident;
2957 
2958 	rcu_read_lock();
2959 	xps = xprt_switch_get(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
2960 	xprt = xprt_iter_xprt(&clnt->cl_xpi);
2961 	if (xps == NULL || xprt == NULL) {
2962 		rcu_read_unlock();
2963 		xprt_switch_put(xps);
2964 		return -EAGAIN;
2965 	}
2966 	resvport = xprt->resvport;
2967 	reuseport = xprt->reuseport;
2968 	connect_timeout = xprt->connect_timeout;
2969 	reconnect_timeout = xprt->max_reconnect_timeout;
2970 	ident = xprt->xprt_class->ident;
2971 	rcu_read_unlock();
2972 
2973 	if (!xprtargs->ident)
2974 		xprtargs->ident = ident;
2975 	xprt = xprt_create_transport(xprtargs);
2976 	if (IS_ERR(xprt)) {
2977 		ret = PTR_ERR(xprt);
2978 		goto out_put_switch;
2979 	}
2980 	xprt->resvport = resvport;
2981 	xprt->reuseport = reuseport;
2982 	if (xprt->ops->set_connect_timeout != NULL)
2983 		xprt->ops->set_connect_timeout(xprt,
2984 				connect_timeout,
2985 				reconnect_timeout);
2986 
2987 	rpc_xprt_switch_set_roundrobin(xps);
2988 	if (setup) {
2989 		ret = setup(clnt, xps, xprt, data);
2990 		if (ret != 0)
2991 			goto out_put_xprt;
2992 	}
2993 	rpc_xprt_switch_add_xprt(xps, xprt);
2994 out_put_xprt:
2995 	xprt_put(xprt);
2996 out_put_switch:
2997 	xprt_switch_put(xps);
2998 	return ret;
2999 }
3000 EXPORT_SYMBOL_GPL(rpc_clnt_add_xprt);
3001 
3002 struct connect_timeout_data {
3003 	unsigned long connect_timeout;
3004 	unsigned long reconnect_timeout;
3005 };
3006 
3007 static int
3008 rpc_xprt_set_connect_timeout(struct rpc_clnt *clnt,
3009 		struct rpc_xprt *xprt,
3010 		void *data)
3011 {
3012 	struct connect_timeout_data *timeo = data;
3013 
3014 	if (xprt->ops->set_connect_timeout)
3015 		xprt->ops->set_connect_timeout(xprt,
3016 				timeo->connect_timeout,
3017 				timeo->reconnect_timeout);
3018 	return 0;
3019 }
3020 
3021 void
3022 rpc_set_connect_timeout(struct rpc_clnt *clnt,
3023 		unsigned long connect_timeout,
3024 		unsigned long reconnect_timeout)
3025 {
3026 	struct connect_timeout_data timeout = {
3027 		.connect_timeout = connect_timeout,
3028 		.reconnect_timeout = reconnect_timeout,
3029 	};
3030 	rpc_clnt_iterate_for_each_xprt(clnt,
3031 			rpc_xprt_set_connect_timeout,
3032 			&timeout);
3033 }
3034 EXPORT_SYMBOL_GPL(rpc_set_connect_timeout);
3035 
3036 void rpc_clnt_xprt_switch_put(struct rpc_clnt *clnt)
3037 {
3038 	rcu_read_lock();
3039 	xprt_switch_put(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
3040 	rcu_read_unlock();
3041 }
3042 EXPORT_SYMBOL_GPL(rpc_clnt_xprt_switch_put);
3043 
3044 void rpc_clnt_xprt_switch_add_xprt(struct rpc_clnt *clnt, struct rpc_xprt *xprt)
3045 {
3046 	rcu_read_lock();
3047 	rpc_xprt_switch_add_xprt(rcu_dereference(clnt->cl_xpi.xpi_xpswitch),
3048 				 xprt);
3049 	rcu_read_unlock();
3050 }
3051 EXPORT_SYMBOL_GPL(rpc_clnt_xprt_switch_add_xprt);
3052 
3053 bool rpc_clnt_xprt_switch_has_addr(struct rpc_clnt *clnt,
3054 				   const struct sockaddr *sap)
3055 {
3056 	struct rpc_xprt_switch *xps;
3057 	bool ret;
3058 
3059 	rcu_read_lock();
3060 	xps = rcu_dereference(clnt->cl_xpi.xpi_xpswitch);
3061 	ret = rpc_xprt_switch_has_addr(xps, sap);
3062 	rcu_read_unlock();
3063 	return ret;
3064 }
3065 EXPORT_SYMBOL_GPL(rpc_clnt_xprt_switch_has_addr);
3066 
3067 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
3068 static void rpc_show_header(void)
3069 {
3070 	printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
3071 		"-timeout ---ops--\n");
3072 }
3073 
3074 static void rpc_show_task(const struct rpc_clnt *clnt,
3075 			  const struct rpc_task *task)
3076 {
3077 	const char *rpc_waitq = "none";
3078 
3079 	if (RPC_IS_QUEUED(task))
3080 		rpc_waitq = rpc_qname(task->tk_waitqueue);
3081 
3082 	printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
3083 		task->tk_pid, task->tk_flags, task->tk_status,
3084 		clnt, task->tk_rqstp, rpc_task_timeout(task), task->tk_ops,
3085 		clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
3086 		task->tk_action, rpc_waitq);
3087 }
3088 
3089 void rpc_show_tasks(struct net *net)
3090 {
3091 	struct rpc_clnt *clnt;
3092 	struct rpc_task *task;
3093 	int header = 0;
3094 	struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
3095 
3096 	spin_lock(&sn->rpc_client_lock);
3097 	list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
3098 		spin_lock(&clnt->cl_lock);
3099 		list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
3100 			if (!header) {
3101 				rpc_show_header();
3102 				header++;
3103 			}
3104 			rpc_show_task(clnt, task);
3105 		}
3106 		spin_unlock(&clnt->cl_lock);
3107 	}
3108 	spin_unlock(&sn->rpc_client_lock);
3109 }
3110 #endif
3111 
3112 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
3113 static int
3114 rpc_clnt_swap_activate_callback(struct rpc_clnt *clnt,
3115 		struct rpc_xprt *xprt,
3116 		void *dummy)
3117 {
3118 	return xprt_enable_swap(xprt);
3119 }
3120 
3121 int
3122 rpc_clnt_swap_activate(struct rpc_clnt *clnt)
3123 {
3124 	while (clnt != clnt->cl_parent)
3125 		clnt = clnt->cl_parent;
3126 	if (atomic_inc_return(&clnt->cl_swapper) == 1)
3127 		return rpc_clnt_iterate_for_each_xprt(clnt,
3128 				rpc_clnt_swap_activate_callback, NULL);
3129 	return 0;
3130 }
3131 EXPORT_SYMBOL_GPL(rpc_clnt_swap_activate);
3132 
3133 static int
3134 rpc_clnt_swap_deactivate_callback(struct rpc_clnt *clnt,
3135 		struct rpc_xprt *xprt,
3136 		void *dummy)
3137 {
3138 	xprt_disable_swap(xprt);
3139 	return 0;
3140 }
3141 
3142 void
3143 rpc_clnt_swap_deactivate(struct rpc_clnt *clnt)
3144 {
3145 	if (atomic_dec_if_positive(&clnt->cl_swapper) == 0)
3146 		rpc_clnt_iterate_for_each_xprt(clnt,
3147 				rpc_clnt_swap_deactivate_callback, NULL);
3148 }
3149 EXPORT_SYMBOL_GPL(rpc_clnt_swap_deactivate);
3150 #endif /* CONFIG_SUNRPC_SWAP */
3151