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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(args->protocol != XPRT_TRANSPORT_BC_TCP);
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(args->protocol != XPRT_TRANSPORT_BC_TCP);
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_get_timeout - Get timeout for transport in units of HZ
1437  * @clnt: RPC client to query
1438  */
1439 unsigned long rpc_get_timeout(struct rpc_clnt *clnt)
1440 {
1441         unsigned long ret;
1442 
1443         rcu_read_lock();
1444         ret = rcu_dereference(clnt->cl_xprt)->timeout->to_initval;
1445         rcu_read_unlock();
1446         return ret;
1447 }
1448 EXPORT_SYMBOL_GPL(rpc_get_timeout);
1449 
1450 /**
1451  * rpc_force_rebind - force transport to check that remote port is unchanged
1452  * @clnt: client to rebind
1453  *
1454  */
1455 void rpc_force_rebind(struct rpc_clnt *clnt)
1456 {
1457         if (clnt->cl_autobind) {
1458                 rcu_read_lock();
1459                 xprt_clear_bound(rcu_dereference(clnt->cl_xprt));
1460                 rcu_read_unlock();
1461         }
1462 }
1463 EXPORT_SYMBOL_GPL(rpc_force_rebind);
1464 
1465 /*
1466  * Restart an (async) RPC call from the call_prepare state.
1467  * Usually called from within the exit handler.
1468  */
1469 int
1470 rpc_restart_call_prepare(struct rpc_task *task)
1471 {
1472         if (RPC_ASSASSINATED(task))
1473                 return 0;
1474         task->tk_action = call_start;
1475         task->tk_status = 0;
1476         if (task->tk_ops->rpc_call_prepare != NULL)
1477                 task->tk_action = rpc_prepare_task;
1478         return 1;
1479 }
1480 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);
1481 
1482 /*
1483  * Restart an (async) RPC call. Usually called from within the
1484  * exit handler.
1485  */
1486 int
1487 rpc_restart_call(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         return 1;
1494 }
1495 EXPORT_SYMBOL_GPL(rpc_restart_call);
1496 
1497 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
1498 const char
1499 *rpc_proc_name(const struct rpc_task *task)
1500 {
1501         const struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1502 
1503         if (proc) {
1504                 if (proc->p_name)
1505                         return proc->p_name;
1506                 else
1507                         return "NULL";
1508         } else
1509                 return "no proc";
1510 }
1511 #endif
1512 
1513 /*
1514  * 0.  Initial state
1515  *
1516  *     Other FSM states can be visited zero or more times, but
1517  *     this state is visited exactly once for each RPC.
1518  */
1519 static void
1520 call_start(struct rpc_task *task)
1521 {
1522         struct rpc_clnt *clnt = task->tk_client;
1523 
1524         dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task->tk_pid,
1525                         clnt->cl_program->name, clnt->cl_vers,
1526                         rpc_proc_name(task),
1527                         (RPC_IS_ASYNC(task) ? "async" : "sync"));
1528 
1529         /* Increment call count */
1530         task->tk_msg.rpc_proc->p_count++;
1531         clnt->cl_stats->rpccnt++;
1532         task->tk_action = call_reserve;
1533 }
1534 
1535 /*
1536  * 1.   Reserve an RPC call slot
1537  */
1538 static void
1539 call_reserve(struct rpc_task *task)
1540 {
1541         dprint_status(task);
1542 
1543         task->tk_status  = 0;
1544         task->tk_action  = call_reserveresult;
1545         xprt_reserve(task);
1546 }
1547 
1548 static void call_retry_reserve(struct rpc_task *task);
1549 
1550 /*
1551  * 1b.  Grok the result of xprt_reserve()
1552  */
1553 static void
1554 call_reserveresult(struct rpc_task *task)
1555 {
1556         int status = task->tk_status;
1557 
1558         dprint_status(task);
1559 
1560         /*
1561          * After a call to xprt_reserve(), we must have either
1562          * a request slot or else an error status.
1563          */
1564         task->tk_status = 0;
1565         if (status >= 0) {
1566                 if (task->tk_rqstp) {
1567                         task->tk_action = call_refresh;
1568                         return;
1569                 }
1570 
1571                 printk(KERN_ERR "%s: status=%d, but no request slot, exiting\n",
1572                                 __func__, status);
1573                 rpc_exit(task, -EIO);
1574                 return;
1575         }
1576 
1577         /*
1578          * Even though there was an error, we may have acquired
1579          * a request slot somehow.  Make sure not to leak it.
1580          */
1581         if (task->tk_rqstp) {
1582                 printk(KERN_ERR "%s: status=%d, request allocated anyway\n",
1583                                 __func__, status);
1584                 xprt_release(task);
1585         }
1586 
1587         switch (status) {
1588         case -ENOMEM:
1589                 rpc_delay(task, HZ >> 2);
1590         case -EAGAIN:   /* woken up; retry */
1591                 task->tk_action = call_retry_reserve;
1592                 return;
1593         case -EIO:      /* probably a shutdown */
1594                 break;
1595         default:
1596                 printk(KERN_ERR "%s: unrecognized error %d, exiting\n",
1597                                 __func__, status);
1598                 break;
1599         }
1600         rpc_exit(task, status);
1601 }
1602 
1603 /*
1604  * 1c.  Retry reserving an RPC call slot
1605  */
1606 static void
1607 call_retry_reserve(struct rpc_task *task)
1608 {
1609         dprint_status(task);
1610 
1611         task->tk_status  = 0;
1612         task->tk_action  = call_reserveresult;
1613         xprt_retry_reserve(task);
1614 }
1615 
1616 /*
1617  * 2.   Bind and/or refresh the credentials
1618  */
1619 static void
1620 call_refresh(struct rpc_task *task)
1621 {
1622         dprint_status(task);
1623 
1624         task->tk_action = call_refreshresult;
1625         task->tk_status = 0;
1626         task->tk_client->cl_stats->rpcauthrefresh++;
1627         rpcauth_refreshcred(task);
1628 }
1629 
1630 /*
1631  * 2a.  Process the results of a credential refresh
1632  */
1633 static void
1634 call_refreshresult(struct rpc_task *task)
1635 {
1636         int status = task->tk_status;
1637 
1638         dprint_status(task);
1639 
1640         task->tk_status = 0;
1641         task->tk_action = call_refresh;
1642         switch (status) {
1643         case 0:
1644                 if (rpcauth_uptodatecred(task)) {
1645                         task->tk_action = call_allocate;
1646                         return;
1647                 }
1648                 /* Use rate-limiting and a max number of retries if refresh
1649                  * had status 0 but failed to update the cred.
1650                  */
1651         case -ETIMEDOUT:
1652                 rpc_delay(task, 3*HZ);
1653         case -EAGAIN:
1654                 status = -EACCES;
1655         case -EKEYEXPIRED:
1656                 if (!task->tk_cred_retry)
1657                         break;
1658                 task->tk_cred_retry--;
1659                 dprintk("RPC: %5u %s: retry refresh creds\n",
1660                                 task->tk_pid, __func__);
1661                 return;
1662         }
1663         dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1664                                 task->tk_pid, __func__, status);
1665         rpc_exit(task, status);
1666 }
1667 
1668 /*
1669  * 2b.  Allocate the buffer. For details, see sched.c:rpc_malloc.
1670  *      (Note: buffer memory is freed in xprt_release).
1671  */
1672 static void
1673 call_allocate(struct rpc_task *task)
1674 {
1675         unsigned int slack = task->tk_rqstp->rq_cred->cr_auth->au_cslack;
1676         struct rpc_rqst *req = task->tk_rqstp;
1677         struct rpc_xprt *xprt = req->rq_xprt;
1678         struct rpc_procinfo *proc = task->tk_msg.rpc_proc;
1679 
1680         dprint_status(task);
1681 
1682         task->tk_status = 0;
1683         task->tk_action = call_bind;
1684 
1685         if (req->rq_buffer)
1686                 return;
1687 
1688         if (proc->p_proc != 0) {
1689                 BUG_ON(proc->p_arglen == 0);
1690                 if (proc->p_decode != NULL)
1691                         BUG_ON(proc->p_replen == 0);
1692         }
1693 
1694         /*
1695          * Calculate the size (in quads) of the RPC call
1696          * and reply headers, and convert both values
1697          * to byte sizes.
1698          */
1699         req->rq_callsize = RPC_CALLHDRSIZE + (slack << 1) + proc->p_arglen;
1700         req->rq_callsize <<= 2;
1701         req->rq_rcvsize = RPC_REPHDRSIZE + slack + proc->p_replen;
1702         req->rq_rcvsize <<= 2;
1703 
1704         req->rq_buffer = xprt->ops->buf_alloc(task,
1705                                         req->rq_callsize + req->rq_rcvsize);
1706         if (req->rq_buffer != NULL)
1707                 return;
1708         xprt_inject_disconnect(xprt);
1709 
1710         dprintk("RPC: %5u rpc_buffer allocation failed\n", task->tk_pid);
1711 
1712         if (RPC_IS_ASYNC(task) || !fatal_signal_pending(current)) {
1713                 task->tk_action = call_allocate;
1714                 rpc_delay(task, HZ>>4);
1715                 return;
1716         }
1717 
1718         rpc_exit(task, -ERESTARTSYS);
1719 }
1720 
1721 static inline int
1722 rpc_task_need_encode(struct rpc_task *task)
1723 {
1724         return task->tk_rqstp->rq_snd_buf.len == 0;
1725 }
1726 
1727 static inline void
1728 rpc_task_force_reencode(struct rpc_task *task)
1729 {
1730         task->tk_rqstp->rq_snd_buf.len = 0;
1731         task->tk_rqstp->rq_bytes_sent = 0;
1732 }
1733 
1734 static inline void
1735 rpc_xdr_buf_init(struct xdr_buf *buf, void *start, size_t len)
1736 {
1737         buf->head[0].iov_base = start;
1738         buf->head[0].iov_len = len;
1739         buf->tail[0].iov_len = 0;
1740         buf->page_len = 0;
1741         buf->flags = 0;
1742         buf->len = 0;
1743         buf->buflen = len;
1744 }
1745 
1746 /*
1747  * 3.   Encode arguments of an RPC call
1748  */
1749 static void
1750 rpc_xdr_encode(struct rpc_task *task)
1751 {
1752         struct rpc_rqst *req = task->tk_rqstp;
1753         kxdreproc_t     encode;
1754         __be32          *p;
1755 
1756         dprint_status(task);
1757 
1758         rpc_xdr_buf_init(&req->rq_snd_buf,
1759                          req->rq_buffer,
1760                          req->rq_callsize);
1761         rpc_xdr_buf_init(&req->rq_rcv_buf,
1762                          (char *)req->rq_buffer + req->rq_callsize,
1763                          req->rq_rcvsize);
1764 
1765         p = rpc_encode_header(task);
1766         if (p == NULL) {
1767                 printk(KERN_INFO "RPC: couldn't encode RPC header, exit EIO\n");
1768                 rpc_exit(task, -EIO);
1769                 return;
1770         }
1771 
1772         encode = task->tk_msg.rpc_proc->p_encode;
1773         if (encode == NULL)
1774                 return;
1775 
1776         task->tk_status = rpcauth_wrap_req(task, encode, req, p,
1777                         task->tk_msg.rpc_argp);
1778 }
1779 
1780 /*
1781  * 4.   Get the server port number if not yet set
1782  */
1783 static void
1784 call_bind(struct rpc_task *task)
1785 {
1786         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1787 
1788         dprint_status(task);
1789 
1790         task->tk_action = call_connect;
1791         if (!xprt_bound(xprt)) {
1792                 task->tk_action = call_bind_status;
1793                 task->tk_timeout = xprt->bind_timeout;
1794                 xprt->ops->rpcbind(task);
1795         }
1796 }
1797 
1798 /*
1799  * 4a.  Sort out bind result
1800  */
1801 static void
1802 call_bind_status(struct rpc_task *task)
1803 {
1804         int status = -EIO;
1805 
1806         if (task->tk_status >= 0) {
1807                 dprint_status(task);
1808                 task->tk_status = 0;
1809                 task->tk_action = call_connect;
1810                 return;
1811         }
1812 
1813         trace_rpc_bind_status(task);
1814         switch (task->tk_status) {
1815         case -ENOMEM:
1816                 dprintk("RPC: %5u rpcbind out of memory\n", task->tk_pid);
1817                 rpc_delay(task, HZ >> 2);
1818                 goto retry_timeout;
1819         case -EACCES:
1820                 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1821                                 "unavailable\n", task->tk_pid);
1822                 /* fail immediately if this is an RPC ping */
1823                 if (task->tk_msg.rpc_proc->p_proc == 0) {
1824                         status = -EOPNOTSUPP;
1825                         break;
1826                 }
1827                 if (task->tk_rebind_retry == 0)
1828                         break;
1829                 task->tk_rebind_retry--;
1830                 rpc_delay(task, 3*HZ);
1831                 goto retry_timeout;
1832         case -ETIMEDOUT:
1833                 dprintk("RPC: %5u rpcbind request timed out\n",
1834                                 task->tk_pid);
1835                 goto retry_timeout;
1836         case -EPFNOSUPPORT:
1837                 /* server doesn't support any rpcbind version we know of */
1838                 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1839                                 task->tk_pid);
1840                 break;
1841         case -EPROTONOSUPPORT:
1842                 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1843                                 task->tk_pid);
1844                 goto retry_timeout;
1845         case -ECONNREFUSED:             /* connection problems */
1846         case -ECONNRESET:
1847         case -ECONNABORTED:
1848         case -ENOTCONN:
1849         case -EHOSTDOWN:
1850         case -EHOSTUNREACH:
1851         case -ENETUNREACH:
1852         case -ENOBUFS:
1853         case -EPIPE:
1854                 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1855                                 task->tk_pid, task->tk_status);
1856                 if (!RPC_IS_SOFTCONN(task)) {
1857                         rpc_delay(task, 5*HZ);
1858                         goto retry_timeout;
1859                 }
1860                 status = task->tk_status;
1861                 break;
1862         default:
1863                 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1864                                 task->tk_pid, -task->tk_status);
1865         }
1866 
1867         rpc_exit(task, status);
1868         return;
1869 
1870 retry_timeout:
1871         task->tk_status = 0;
1872         task->tk_action = call_timeout;
1873 }
1874 
1875 /*
1876  * 4b.  Connect to the RPC server
1877  */
1878 static void
1879 call_connect(struct rpc_task *task)
1880 {
1881         struct rpc_xprt *xprt = task->tk_rqstp->rq_xprt;
1882 
1883         dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1884                         task->tk_pid, xprt,
1885                         (xprt_connected(xprt) ? "is" : "is not"));
1886 
1887         task->tk_action = call_transmit;
1888         if (!xprt_connected(xprt)) {
1889                 task->tk_action = call_connect_status;
1890                 if (task->tk_status < 0)
1891                         return;
1892                 if (task->tk_flags & RPC_TASK_NOCONNECT) {
1893                         rpc_exit(task, -ENOTCONN);
1894                         return;
1895                 }
1896                 xprt_connect(task);
1897         }
1898 }
1899 
1900 /*
1901  * 4c.  Sort out connect result
1902  */
1903 static void
1904 call_connect_status(struct rpc_task *task)
1905 {
1906         struct rpc_clnt *clnt = task->tk_client;
1907         int status = task->tk_status;
1908 
1909         dprint_status(task);
1910 
1911         trace_rpc_connect_status(task, status);
1912         task->tk_status = 0;
1913         switch (status) {
1914         case -ECONNREFUSED:
1915         case -ECONNRESET:
1916         case -ECONNABORTED:
1917         case -ENETUNREACH:
1918         case -EHOSTUNREACH:
1919         case -EADDRINUSE:
1920         case -ENOBUFS:
1921         case -EPIPE:
1922                 if (RPC_IS_SOFTCONN(task))
1923                         break;
1924                 /* retry with existing socket, after a delay */
1925                 rpc_delay(task, 3*HZ);
1926         case -EAGAIN:
1927                 /* Check for timeouts before looping back to call_bind */
1928         case -ETIMEDOUT:
1929                 task->tk_action = call_timeout;
1930                 return;
1931         case 0:
1932                 clnt->cl_stats->netreconn++;
1933                 task->tk_action = call_transmit;
1934                 return;
1935         }
1936         rpc_exit(task, status);
1937 }
1938 
1939 /*
1940  * 5.   Transmit the RPC request, and wait for reply
1941  */
1942 static void
1943 call_transmit(struct rpc_task *task)
1944 {
1945         int is_retrans = RPC_WAS_SENT(task);
1946 
1947         dprint_status(task);
1948 
1949         task->tk_action = call_status;
1950         if (task->tk_status < 0)
1951                 return;
1952         if (!xprt_prepare_transmit(task))
1953                 return;
1954         task->tk_action = call_transmit_status;
1955         /* Encode here so that rpcsec_gss can use correct sequence number. */
1956         if (rpc_task_need_encode(task)) {
1957                 rpc_xdr_encode(task);
1958                 /* Did the encode result in an error condition? */
1959                 if (task->tk_status != 0) {
1960                         /* Was the error nonfatal? */
1961                         if (task->tk_status == -EAGAIN)
1962                                 rpc_delay(task, HZ >> 4);
1963                         else
1964                                 rpc_exit(task, task->tk_status);
1965                         return;
1966                 }
1967         }
1968         xprt_transmit(task);
1969         if (task->tk_status < 0)
1970                 return;
1971         if (is_retrans)
1972                 task->tk_client->cl_stats->rpcretrans++;
1973         /*
1974          * On success, ensure that we call xprt_end_transmit() before sleeping
1975          * in order to allow access to the socket to other RPC requests.
1976          */
1977         call_transmit_status(task);
1978         if (rpc_reply_expected(task))
1979                 return;
1980         task->tk_action = rpc_exit_task;
1981         rpc_wake_up_queued_task(&task->tk_rqstp->rq_xprt->pending, task);
1982 }
1983 
1984 /*
1985  * 5a.  Handle cleanup after a transmission
1986  */
1987 static void
1988 call_transmit_status(struct rpc_task *task)
1989 {
1990         task->tk_action = call_status;
1991 
1992         /*
1993          * Common case: success.  Force the compiler to put this
1994          * test first.
1995          */
1996         if (task->tk_status == 0) {
1997                 xprt_end_transmit(task);
1998                 rpc_task_force_reencode(task);
1999                 return;
2000         }
2001 
2002         switch (task->tk_status) {
2003         case -EAGAIN:
2004         case -ENOBUFS:
2005                 break;
2006         default:
2007                 dprint_status(task);
2008                 xprt_end_transmit(task);
2009                 rpc_task_force_reencode(task);
2010                 break;
2011                 /*
2012                  * Special cases: if we've been waiting on the
2013                  * socket's write_space() callback, or if the
2014                  * socket just returned a connection error,
2015                  * then hold onto the transport lock.
2016                  */
2017         case -ECONNREFUSED:
2018         case -EHOSTDOWN:
2019         case -EHOSTUNREACH:
2020         case -ENETUNREACH:
2021         case -EPERM:
2022                 if (RPC_IS_SOFTCONN(task)) {
2023                         xprt_end_transmit(task);
2024                         rpc_exit(task, task->tk_status);
2025                         break;
2026                 }
2027         case -ECONNRESET:
2028         case -ECONNABORTED:
2029         case -EADDRINUSE:
2030         case -ENOTCONN:
2031         case -EPIPE:
2032                 rpc_task_force_reencode(task);
2033         }
2034 }
2035 
2036 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
2037 /*
2038  * 5b.  Send the backchannel RPC reply.  On error, drop the reply.  In
2039  * addition, disconnect on connectivity errors.
2040  */
2041 static void
2042 call_bc_transmit(struct rpc_task *task)
2043 {
2044         struct rpc_rqst *req = task->tk_rqstp;
2045 
2046         if (!xprt_prepare_transmit(task))
2047                 goto out_retry;
2048 
2049         if (task->tk_status < 0) {
2050                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
2051                         "error: %d\n", task->tk_status);
2052                 goto out_done;
2053         }
2054         if (req->rq_connect_cookie != req->rq_xprt->connect_cookie)
2055                 req->rq_bytes_sent = 0;
2056 
2057         xprt_transmit(task);
2058 
2059         if (task->tk_status == -EAGAIN)
2060                 goto out_nospace;
2061 
2062         xprt_end_transmit(task);
2063         dprint_status(task);
2064         switch (task->tk_status) {
2065         case 0:
2066                 /* Success */
2067         case -EHOSTDOWN:
2068         case -EHOSTUNREACH:
2069         case -ENETUNREACH:
2070         case -ECONNRESET:
2071         case -ECONNREFUSED:
2072         case -EADDRINUSE:
2073         case -ENOTCONN:
2074         case -EPIPE:
2075                 break;
2076         case -ETIMEDOUT:
2077                 /*
2078                  * Problem reaching the server.  Disconnect and let the
2079                  * forechannel reestablish the connection.  The server will
2080                  * have to retransmit the backchannel request and we'll
2081                  * reprocess it.  Since these ops are idempotent, there's no
2082                  * need to cache our reply at this time.
2083                  */
2084                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
2085                         "error: %d\n", task->tk_status);
2086                 xprt_conditional_disconnect(req->rq_xprt,
2087                         req->rq_connect_cookie);
2088                 break;
2089         default:
2090                 /*
2091                  * We were unable to reply and will have to drop the
2092                  * request.  The server should reconnect and retransmit.
2093                  */
2094                 WARN_ON_ONCE(task->tk_status == -EAGAIN);
2095                 printk(KERN_NOTICE "RPC: Could not send backchannel reply "
2096                         "error: %d\n", task->tk_status);
2097                 break;
2098         }
2099         rpc_wake_up_queued_task(&req->rq_xprt->pending, task);
2100 out_done:
2101         task->tk_action = rpc_exit_task;
2102         return;
2103 out_nospace:
2104         req->rq_connect_cookie = req->rq_xprt->connect_cookie;
2105 out_retry:
2106         task->tk_status = 0;
2107 }
2108 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
2109 
2110 /*
2111  * 6.   Sort out the RPC call status
2112  */
2113 static void
2114 call_status(struct rpc_task *task)
2115 {
2116         struct rpc_clnt *clnt = task->tk_client;
2117         struct rpc_rqst *req = task->tk_rqstp;
2118         int             status;
2119 
2120         if (req->rq_reply_bytes_recvd > 0 && !req->rq_bytes_sent)
2121                 task->tk_status = req->rq_reply_bytes_recvd;
2122 
2123         dprint_status(task);
2124 
2125         status = task->tk_status;
2126         if (status >= 0) {
2127                 task->tk_action = call_decode;
2128                 return;
2129         }
2130 
2131         trace_rpc_call_status(task);
2132         task->tk_status = 0;
2133         switch(status) {
2134         case -EHOSTDOWN:
2135         case -EHOSTUNREACH:
2136         case -ENETUNREACH:
2137         case -EPERM:
2138                 if (RPC_IS_SOFTCONN(task)) {
2139                         rpc_exit(task, status);
2140                         break;
2141                 }
2142                 /*
2143                  * Delay any retries for 3 seconds, then handle as if it
2144                  * were a timeout.
2145                  */
2146                 rpc_delay(task, 3*HZ);
2147         case -ETIMEDOUT:
2148                 task->tk_action = call_timeout;
2149                 if (!(task->tk_flags & RPC_TASK_NO_RETRANS_TIMEOUT)
2150                     && task->tk_client->cl_discrtry)
2151                         xprt_conditional_disconnect(req->rq_xprt,
2152                                         req->rq_connect_cookie);
2153                 break;
2154         case -ECONNREFUSED:
2155         case -ECONNRESET:
2156         case -ECONNABORTED:
2157                 rpc_force_rebind(clnt);
2158         case -EADDRINUSE:
2159                 rpc_delay(task, 3*HZ);
2160         case -EPIPE:
2161         case -ENOTCONN:
2162                 task->tk_action = call_bind;
2163                 break;
2164         case -ENOBUFS:
2165                 rpc_delay(task, HZ>>2);
2166         case -EAGAIN:
2167                 task->tk_action = call_transmit;
2168                 break;
2169         case -EIO:
2170                 /* shutdown or soft timeout */
2171                 rpc_exit(task, status);
2172                 break;
2173         default:
2174                 if (clnt->cl_chatty)
2175                         printk("%s: RPC call returned error %d\n",
2176                                clnt->cl_program->name, -status);
2177                 rpc_exit(task, status);
2178         }
2179 }
2180 
2181 /*
2182  * 6a.  Handle RPC timeout
2183  *      We do not release the request slot, so we keep using the
2184  *      same XID for all retransmits.
2185  */
2186 static void
2187 call_timeout(struct rpc_task *task)
2188 {
2189         struct rpc_clnt *clnt = task->tk_client;
2190 
2191         if (xprt_adjust_timeout(task->tk_rqstp) == 0) {
2192                 dprintk("RPC: %5u call_timeout (minor)\n", task->tk_pid);
2193                 goto retry;
2194         }
2195 
2196         dprintk("RPC: %5u call_timeout (major)\n", task->tk_pid);
2197         task->tk_timeouts++;
2198 
2199         if (RPC_IS_SOFTCONN(task)) {
2200                 rpc_exit(task, -ETIMEDOUT);
2201                 return;
2202         }
2203         if (RPC_IS_SOFT(task)) {
2204                 if (clnt->cl_chatty) {
2205                         printk(KERN_NOTICE "%s: server %s not responding, timed out\n",
2206                                 clnt->cl_program->name,
2207                                 task->tk_xprt->servername);
2208                 }
2209                 if (task->tk_flags & RPC_TASK_TIMEOUT)
2210                         rpc_exit(task, -ETIMEDOUT);
2211                 else
2212                         rpc_exit(task, -EIO);
2213                 return;
2214         }
2215 
2216         if (!(task->tk_flags & RPC_CALL_MAJORSEEN)) {
2217                 task->tk_flags |= RPC_CALL_MAJORSEEN;
2218                 if (clnt->cl_chatty) {
2219                         printk(KERN_NOTICE "%s: server %s not responding, still trying\n",
2220                         clnt->cl_program->name,
2221                         task->tk_xprt->servername);
2222                 }
2223         }
2224         rpc_force_rebind(clnt);
2225         /*
2226          * Did our request time out due to an RPCSEC_GSS out-of-sequence
2227          * event? RFC2203 requires the server to drop all such requests.
2228          */
2229         rpcauth_invalcred(task);
2230 
2231 retry:
2232         task->tk_action = call_bind;
2233         task->tk_status = 0;
2234 }
2235 
2236 /*
2237  * 7.   Decode the RPC reply
2238  */
2239 static void
2240 call_decode(struct rpc_task *task)
2241 {
2242         struct rpc_clnt *clnt = task->tk_client;
2243         struct rpc_rqst *req = task->tk_rqstp;
2244         kxdrdproc_t     decode = task->tk_msg.rpc_proc->p_decode;
2245         __be32          *p;
2246 
2247         dprint_status(task);
2248 
2249         if (task->tk_flags & RPC_CALL_MAJORSEEN) {
2250                 if (clnt->cl_chatty) {
2251                         printk(KERN_NOTICE "%s: server %s OK\n",
2252                                 clnt->cl_program->name,
2253                                 task->tk_xprt->servername);
2254                 }
2255                 task->tk_flags &= ~RPC_CALL_MAJORSEEN;
2256         }
2257 
2258         /*
2259          * Ensure that we see all writes made by xprt_complete_rqst()
2260          * before it changed req->rq_reply_bytes_recvd.
2261          */
2262         smp_rmb();
2263         req->rq_rcv_buf.len = req->rq_private_buf.len;
2264 
2265         /* Check that the softirq receive buffer is valid */
2266         WARN_ON(memcmp(&req->rq_rcv_buf, &req->rq_private_buf,
2267                                 sizeof(req->rq_rcv_buf)) != 0);
2268 
2269         if (req->rq_rcv_buf.len < 12) {
2270                 if (!RPC_IS_SOFT(task)) {
2271                         task->tk_action = call_bind;
2272                         goto out_retry;
2273                 }
2274                 dprintk("RPC:       %s: too small RPC reply size (%d bytes)\n",
2275                                 clnt->cl_program->name, task->tk_status);
2276                 task->tk_action = call_timeout;
2277                 goto out_retry;
2278         }
2279 
2280         p = rpc_verify_header(task);
2281         if (IS_ERR(p)) {
2282                 if (p == ERR_PTR(-EAGAIN))
2283                         goto out_retry;
2284                 return;
2285         }
2286 
2287         task->tk_action = rpc_exit_task;
2288 
2289         if (decode) {
2290                 task->tk_status = rpcauth_unwrap_resp(task, decode, req, p,
2291                                                       task->tk_msg.rpc_resp);
2292         }
2293         dprintk("RPC: %5u call_decode result %d\n", task->tk_pid,
2294                         task->tk_status);
2295         return;
2296 out_retry:
2297         task->tk_status = 0;
2298         /* Note: rpc_verify_header() may have freed the RPC slot */
2299         if (task->tk_rqstp == req) {
2300                 req->rq_reply_bytes_recvd = req->rq_rcv_buf.len = 0;
2301                 if (task->tk_client->cl_discrtry)
2302                         xprt_conditional_disconnect(req->rq_xprt,
2303                                         req->rq_connect_cookie);
2304         }
2305 }
2306 
2307 static __be32 *
2308 rpc_encode_header(struct rpc_task *task)
2309 {
2310         struct rpc_clnt *clnt = task->tk_client;
2311         struct rpc_rqst *req = task->tk_rqstp;
2312         __be32          *p = req->rq_svec[0].iov_base;
2313 
2314         /* FIXME: check buffer size? */
2315 
2316         p = xprt_skip_transport_header(req->rq_xprt, p);
2317         *p++ = req->rq_xid;             /* XID */
2318         *p++ = htonl(RPC_CALL);         /* CALL */
2319         *p++ = htonl(RPC_VERSION);      /* RPC version */
2320         *p++ = htonl(clnt->cl_prog);    /* program number */
2321         *p++ = htonl(clnt->cl_vers);    /* program version */
2322         *p++ = htonl(task->tk_msg.rpc_proc->p_proc);    /* procedure */
2323         p = rpcauth_marshcred(task, p);
2324         req->rq_slen = xdr_adjust_iovec(&req->rq_svec[0], p);
2325         return p;
2326 }
2327 
2328 static __be32 *
2329 rpc_verify_header(struct rpc_task *task)
2330 {
2331         struct rpc_clnt *clnt = task->tk_client;
2332         struct kvec *iov = &task->tk_rqstp->rq_rcv_buf.head[0];
2333         int len = task->tk_rqstp->rq_rcv_buf.len >> 2;
2334         __be32  *p = iov->iov_base;
2335         u32 n;
2336         int error = -EACCES;
2337 
2338         if ((task->tk_rqstp->rq_rcv_buf.len & 3) != 0) {
2339                 /* RFC-1014 says that the representation of XDR data must be a
2340                  * multiple of four bytes
2341                  * - if it isn't pointer subtraction in the NFS client may give
2342                  *   undefined results
2343                  */
2344                 dprintk("RPC: %5u %s: XDR representation not a multiple of"
2345                        " 4 bytes: 0x%x\n", task->tk_pid, __func__,
2346                        task->tk_rqstp->rq_rcv_buf.len);
2347                 error = -EIO;
2348                 goto out_err;
2349         }
2350         if ((len -= 3) < 0)
2351                 goto out_overflow;
2352 
2353         p += 1; /* skip XID */
2354         if ((n = ntohl(*p++)) != RPC_REPLY) {
2355                 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2356                         task->tk_pid, __func__, n);
2357                 error = -EIO;
2358                 goto out_garbage;
2359         }
2360 
2361         if ((n = ntohl(*p++)) != RPC_MSG_ACCEPTED) {
2362                 if (--len < 0)
2363                         goto out_overflow;
2364                 switch ((n = ntohl(*p++))) {
2365                 case RPC_AUTH_ERROR:
2366                         break;
2367                 case RPC_MISMATCH:
2368                         dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2369                                 task->tk_pid, __func__);
2370                         error = -EPROTONOSUPPORT;
2371                         goto out_err;
2372                 default:
2373                         dprintk("RPC: %5u %s: RPC call rejected, "
2374                                 "unknown error: %x\n",
2375                                 task->tk_pid, __func__, n);
2376                         error = -EIO;
2377                         goto out_err;
2378                 }
2379                 if (--len < 0)
2380                         goto out_overflow;
2381                 switch ((n = ntohl(*p++))) {
2382                 case RPC_AUTH_REJECTEDCRED:
2383                 case RPC_AUTH_REJECTEDVERF:
2384                 case RPCSEC_GSS_CREDPROBLEM:
2385                 case RPCSEC_GSS_CTXPROBLEM:
2386                         if (!task->tk_cred_retry)
2387                                 break;
2388                         task->tk_cred_retry--;
2389                         dprintk("RPC: %5u %s: retry stale creds\n",
2390                                         task->tk_pid, __func__);
2391                         rpcauth_invalcred(task);
2392                         /* Ensure we obtain a new XID! */
2393                         xprt_release(task);
2394                         task->tk_action = call_reserve;
2395                         goto out_retry;
2396                 case RPC_AUTH_BADCRED:
2397                 case RPC_AUTH_BADVERF:
2398                         /* possibly garbled cred/verf? */
2399                         if (!task->tk_garb_retry)
2400                                 break;
2401                         task->tk_garb_retry--;
2402                         dprintk("RPC: %5u %s: retry garbled creds\n",
2403                                         task->tk_pid, __func__);
2404                         task->tk_action = call_bind;
2405                         goto out_retry;
2406                 case RPC_AUTH_TOOWEAK:
2407                         printk(KERN_NOTICE "RPC: server %s requires stronger "
2408                                "authentication.\n",
2409                                task->tk_xprt->servername);
2410                         break;
2411                 default:
2412                         dprintk("RPC: %5u %s: unknown auth error: %x\n",
2413                                         task->tk_pid, __func__, n);
2414                         error = -EIO;
2415                 }
2416                 dprintk("RPC: %5u %s: call rejected %d\n",
2417                                 task->tk_pid, __func__, n);
2418                 goto out_err;
2419         }
2420         p = rpcauth_checkverf(task, p);
2421         if (IS_ERR(p)) {
2422                 error = PTR_ERR(p);
2423                 dprintk("RPC: %5u %s: auth check failed with %d\n",
2424                                 task->tk_pid, __func__, error);
2425                 goto out_garbage;               /* bad verifier, retry */
2426         }
2427         len = p - (__be32 *)iov->iov_base - 1;
2428         if (len < 0)
2429                 goto out_overflow;
2430         switch ((n = ntohl(*p++))) {
2431         case RPC_SUCCESS:
2432                 return p;
2433         case RPC_PROG_UNAVAIL:
2434                 dprintk("RPC: %5u %s: program %u is unsupported "
2435                                 "by server %s\n", task->tk_pid, __func__,
2436                                 (unsigned int)clnt->cl_prog,
2437                                 task->tk_xprt->servername);
2438                 error = -EPFNOSUPPORT;
2439                 goto out_err;
2440         case RPC_PROG_MISMATCH:
2441                 dprintk("RPC: %5u %s: program %u, version %u unsupported "
2442                                 "by server %s\n", task->tk_pid, __func__,
2443                                 (unsigned int)clnt->cl_prog,
2444                                 (unsigned int)clnt->cl_vers,
2445                                 task->tk_xprt->servername);
2446                 error = -EPROTONOSUPPORT;
2447                 goto out_err;
2448         case RPC_PROC_UNAVAIL:
2449                 dprintk("RPC: %5u %s: proc %s unsupported by program %u, "
2450                                 "version %u on server %s\n",
2451                                 task->tk_pid, __func__,
2452                                 rpc_proc_name(task),
2453                                 clnt->cl_prog, clnt->cl_vers,
2454                                 task->tk_xprt->servername);
2455                 error = -EOPNOTSUPP;
2456                 goto out_err;
2457         case RPC_GARBAGE_ARGS:
2458                 dprintk("RPC: %5u %s: server saw garbage\n",
2459                                 task->tk_pid, __func__);
2460                 break;                  /* retry */
2461         default:
2462                 dprintk("RPC: %5u %s: server accept status: %x\n",
2463                                 task->tk_pid, __func__, n);
2464                 /* Also retry */
2465         }
2466 
2467 out_garbage:
2468         clnt->cl_stats->rpcgarbage++;
2469         if (task->tk_garb_retry) {
2470                 task->tk_garb_retry--;
2471                 dprintk("RPC: %5u %s: retrying\n",
2472                                 task->tk_pid, __func__);
2473                 task->tk_action = call_bind;
2474 out_retry:
2475                 return ERR_PTR(-EAGAIN);
2476         }
2477 out_err:
2478         rpc_exit(task, error);
2479         dprintk("RPC: %5u %s: call failed with error %d\n", task->tk_pid,
2480                         __func__, error);
2481         return ERR_PTR(error);
2482 out_overflow:
2483         dprintk("RPC: %5u %s: server reply was truncated.\n", task->tk_pid,
2484                         __func__);
2485         goto out_garbage;
2486 }
2487 
2488 static void rpcproc_encode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2489 {
2490 }
2491 
2492 static int rpcproc_decode_null(void *rqstp, struct xdr_stream *xdr, void *obj)
2493 {
2494         return 0;
2495 }
2496 
2497 static struct rpc_procinfo rpcproc_null = {
2498         .p_encode = rpcproc_encode_null,
2499         .p_decode = rpcproc_decode_null,
2500 };
2501 
2502 static int rpc_ping(struct rpc_clnt *clnt)
2503 {
2504         struct rpc_message msg = {
2505                 .rpc_proc = &rpcproc_null,
2506         };
2507         int err;
2508         msg.rpc_cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2509         err = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN);
2510         put_rpccred(msg.rpc_cred);
2511         return err;
2512 }
2513 
2514 static
2515 struct rpc_task *rpc_call_null_helper(struct rpc_clnt *clnt,
2516                 struct rpc_xprt *xprt, struct rpc_cred *cred, int flags,
2517                 const struct rpc_call_ops *ops, void *data)
2518 {
2519         struct rpc_message msg = {
2520                 .rpc_proc = &rpcproc_null,
2521                 .rpc_cred = cred,
2522         };
2523         struct rpc_task_setup task_setup_data = {
2524                 .rpc_client = clnt,
2525                 .rpc_xprt = xprt,
2526                 .rpc_message = &msg,
2527                 .callback_ops = (ops != NULL) ? ops : &rpc_default_ops,
2528                 .callback_data = data,
2529                 .flags = flags,
2530         };
2531 
2532         return rpc_run_task(&task_setup_data);
2533 }
2534 
2535 struct rpc_task *rpc_call_null(struct rpc_clnt *clnt, struct rpc_cred *cred, int flags)
2536 {
2537         return rpc_call_null_helper(clnt, NULL, cred, flags, NULL, NULL);
2538 }
2539 EXPORT_SYMBOL_GPL(rpc_call_null);
2540 
2541 struct rpc_cb_add_xprt_calldata {
2542         struct rpc_xprt_switch *xps;
2543         struct rpc_xprt *xprt;
2544 };
2545 
2546 static void rpc_cb_add_xprt_done(struct rpc_task *task, void *calldata)
2547 {
2548         struct rpc_cb_add_xprt_calldata *data = calldata;
2549 
2550         if (task->tk_status == 0)
2551                 rpc_xprt_switch_add_xprt(data->xps, data->xprt);
2552 }
2553 
2554 static void rpc_cb_add_xprt_release(void *calldata)
2555 {
2556         struct rpc_cb_add_xprt_calldata *data = calldata;
2557 
2558         xprt_put(data->xprt);
2559         xprt_switch_put(data->xps);
2560         kfree(data);
2561 }
2562 
2563 const static struct rpc_call_ops rpc_cb_add_xprt_call_ops = {
2564         .rpc_call_done = rpc_cb_add_xprt_done,
2565         .rpc_release = rpc_cb_add_xprt_release,
2566 };
2567 
2568 /**
2569  * rpc_clnt_test_and_add_xprt - Test and add a new transport to a rpc_clnt
2570  * @clnt: pointer to struct rpc_clnt
2571  * @xps: pointer to struct rpc_xprt_switch,
2572  * @xprt: pointer struct rpc_xprt
2573  * @dummy: unused
2574  */
2575 int rpc_clnt_test_and_add_xprt(struct rpc_clnt *clnt,
2576                 struct rpc_xprt_switch *xps, struct rpc_xprt *xprt,
2577                 void *dummy)
2578 {
2579         struct rpc_cb_add_xprt_calldata *data;
2580         struct rpc_cred *cred;
2581         struct rpc_task *task;
2582 
2583         data = kmalloc(sizeof(*data), GFP_NOFS);
2584         if (!data)
2585                 return -ENOMEM;
2586         data->xps = xprt_switch_get(xps);
2587         data->xprt = xprt_get(xprt);
2588 
2589         cred = authnull_ops.lookup_cred(NULL, NULL, 0);
2590         task = rpc_call_null_helper(clnt, xprt, cred,
2591                         RPC_TASK_SOFT|RPC_TASK_SOFTCONN|RPC_TASK_ASYNC,
2592                         &rpc_cb_add_xprt_call_ops, data);
2593         put_rpccred(cred);
2594         if (IS_ERR(task))
2595                 return PTR_ERR(task);
2596         rpc_put_task(task);
2597         return 1;
2598 }
2599 EXPORT_SYMBOL_GPL(rpc_clnt_test_and_add_xprt);
2600 
2601 /**
2602  * rpc_clnt_add_xprt - Add a new transport to a rpc_clnt
2603  * @clnt: pointer to struct rpc_clnt
2604  * @xprtargs: pointer to struct xprt_create
2605  * @setup: callback to test and/or set up the connection
2606  * @data: pointer to setup function data
2607  *
2608  * Creates a new transport using the parameters set in args and
2609  * adds it to clnt.
2610  * If ping is set, then test that connectivity succeeds before
2611  * adding the new transport.
2612  *
2613  */
2614 int rpc_clnt_add_xprt(struct rpc_clnt *clnt,
2615                 struct xprt_create *xprtargs,
2616                 int (*setup)(struct rpc_clnt *,
2617                         struct rpc_xprt_switch *,
2618                         struct rpc_xprt *,
2619                         void *),
2620                 void *data)
2621 {
2622         struct rpc_xprt_switch *xps;
2623         struct rpc_xprt *xprt;
2624         unsigned char resvport;
2625         int ret = 0;
2626 
2627         rcu_read_lock();
2628         xps = xprt_switch_get(rcu_dereference(clnt->cl_xpi.xpi_xpswitch));
2629         xprt = xprt_iter_xprt(&clnt->cl_xpi);
2630         if (xps == NULL || xprt == NULL) {
2631                 rcu_read_unlock();
2632                 return -EAGAIN;
2633         }
2634         resvport = xprt->resvport;
2635         rcu_read_unlock();
2636 
2637         xprt = xprt_create_transport(xprtargs);
2638         if (IS_ERR(xprt)) {
2639                 ret = PTR_ERR(xprt);
2640                 goto out_put_switch;
2641         }
2642         xprt->resvport = resvport;
2643 
2644         rpc_xprt_switch_set_roundrobin(xps);
2645         if (setup) {
2646                 ret = setup(clnt, xps, xprt, data);
2647                 if (ret != 0)
2648                         goto out_put_xprt;
2649         }
2650         rpc_xprt_switch_add_xprt(xps, xprt);
2651 out_put_xprt:
2652         xprt_put(xprt);
2653 out_put_switch:
2654         xprt_switch_put(xps);
2655         return ret;
2656 }
2657 EXPORT_SYMBOL_GPL(rpc_clnt_add_xprt);
2658 
2659 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
2660 static void rpc_show_header(void)
2661 {
2662         printk(KERN_INFO "-pid- flgs status -client- --rqstp- "
2663                 "-timeout ---ops--\n");
2664 }
2665 
2666 static void rpc_show_task(const struct rpc_clnt *clnt,
2667                           const struct rpc_task *task)
2668 {
2669         const char *rpc_waitq = "none";
2670 
2671         if (RPC_IS_QUEUED(task))
2672                 rpc_waitq = rpc_qname(task->tk_waitqueue);
2673 
2674         printk(KERN_INFO "%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2675                 task->tk_pid, task->tk_flags, task->tk_status,
2676                 clnt, task->tk_rqstp, task->tk_timeout, task->tk_ops,
2677                 clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
2678                 task->tk_action, rpc_waitq);
2679 }
2680 
2681 void rpc_show_tasks(struct net *net)
2682 {
2683         struct rpc_clnt *clnt;
2684         struct rpc_task *task;
2685         int header = 0;
2686         struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
2687 
2688         spin_lock(&sn->rpc_client_lock);
2689         list_for_each_entry(clnt, &sn->all_clients, cl_clients) {
2690                 spin_lock(&clnt->cl_lock);
2691                 list_for_each_entry(task, &clnt->cl_tasks, tk_task) {
2692                         if (!header) {
2693                                 rpc_show_header();
2694                                 header++;
2695                         }
2696                         rpc_show_task(clnt, task);
2697                 }
2698                 spin_unlock(&clnt->cl_lock);
2699         }
2700         spin_unlock(&sn->rpc_client_lock);
2701 }
2702 #endif
2703 
2704 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
2705 static int
2706 rpc_clnt_swap_activate_callback(struct rpc_clnt *clnt,
2707                 struct rpc_xprt *xprt,
2708                 void *dummy)
2709 {
2710         return xprt_enable_swap(xprt);
2711 }
2712 
2713 int
2714 rpc_clnt_swap_activate(struct rpc_clnt *clnt)
2715 {
2716         if (atomic_inc_return(&clnt->cl_swapper) == 1)
2717                 return rpc_clnt_iterate_for_each_xprt(clnt,
2718                                 rpc_clnt_swap_activate_callback, NULL);
2719         return 0;
2720 }
2721 EXPORT_SYMBOL_GPL(rpc_clnt_swap_activate);
2722 
2723 static int
2724 rpc_clnt_swap_deactivate_callback(struct rpc_clnt *clnt,
2725                 struct rpc_xprt *xprt,
2726                 void *dummy)
2727 {
2728         xprt_disable_swap(xprt);
2729         return 0;
2730 }
2731 
2732 void
2733 rpc_clnt_swap_deactivate(struct rpc_clnt *clnt)
2734 {
2735         if (atomic_dec_if_positive(&clnt->cl_swapper) == 0)
2736                 rpc_clnt_iterate_for_each_xprt(clnt,
2737                                 rpc_clnt_swap_deactivate_callback, NULL);
2738 }
2739 EXPORT_SYMBOL_GPL(rpc_clnt_swap_deactivate);
2740 #endif /* CONFIG_SUNRPC_SWAP */
2741 

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