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Linux/net/sunrpc/clnt.c

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

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