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

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