2 * linux/net/sunrpc/clnt.c
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.
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.
16 * Copyright (C) 1992,1993 Rick Sladkey <jrs@world.std.com>
17 * Copyright (C) 1995,1996 Olaf Kirch <okir@monad.swb.de>
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/kallsyms.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>
32 #include <linux/in6.h>
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>
45 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
46 # define RPCDBG_FACILITY RPCDBG_CALL
49 #define dprint_status(t) \
50 dprintk("RPC: %5u %s (status %d)\n", t->tk_pid, \
51 __func__, t->tk_status)
54 * All RPC clients are linked into this list
57 static DECLARE_WAIT_QUEUE_HEAD(destroy_wait
);
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
);
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
);
83 static void rpc_register_client(struct rpc_clnt
*clnt
)
85 struct net
*net
= rpc_net_ns(clnt
);
86 struct sunrpc_net
*sn
= net_generic(net
, sunrpc_net_id
);
88 spin_lock(&sn
->rpc_client_lock
);
89 list_add(&clnt
->cl_clients
, &sn
->all_clients
);
90 spin_unlock(&sn
->rpc_client_lock
);
93 static void rpc_unregister_client(struct rpc_clnt
*clnt
)
95 struct net
*net
= rpc_net_ns(clnt
);
96 struct sunrpc_net
*sn
= net_generic(net
, sunrpc_net_id
);
98 spin_lock(&sn
->rpc_client_lock
);
99 list_del(&clnt
->cl_clients
);
100 spin_unlock(&sn
->rpc_client_lock
);
103 static void __rpc_clnt_remove_pipedir(struct rpc_clnt
*clnt
)
105 rpc_remove_client_dir(clnt
);
108 static void rpc_clnt_remove_pipedir(struct rpc_clnt
*clnt
)
110 struct net
*net
= rpc_net_ns(clnt
);
111 struct super_block
*pipefs_sb
;
113 pipefs_sb
= rpc_get_sb_net(net
);
115 __rpc_clnt_remove_pipedir(clnt
);
120 static struct dentry
*rpc_setup_pipedir_sb(struct super_block
*sb
,
121 struct rpc_clnt
*clnt
)
123 static uint32_t clntid
;
124 const char *dir_name
= clnt
->cl_program
->pipe_dir_name
;
126 struct dentry
*dir
, *dentry
;
128 dir
= rpc_d_lookup_sb(sb
, dir_name
);
130 pr_info("RPC: pipefs directory doesn't exist: %s\n", dir_name
);
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
);
139 if (dentry
== ERR_PTR(-EEXIST
))
141 printk(KERN_INFO
"RPC: Couldn't create pipefs entry"
142 " %s/%s, error %ld\n",
143 dir_name
, name
, PTR_ERR(dentry
));
151 rpc_setup_pipedir(struct super_block
*pipefs_sb
, struct rpc_clnt
*clnt
)
153 struct dentry
*dentry
;
155 if (clnt
->cl_program
->pipe_dir_name
!= NULL
) {
156 dentry
= rpc_setup_pipedir_sb(pipefs_sb
, clnt
);
158 return PTR_ERR(dentry
);
163 static int rpc_clnt_skip_event(struct rpc_clnt
*clnt
, unsigned long event
)
165 if (clnt
->cl_program
->pipe_dir_name
== NULL
)
169 case RPC_PIPEFS_MOUNT
:
170 if (clnt
->cl_pipedir_objects
.pdh_dentry
!= NULL
)
172 if (atomic_read(&clnt
->cl_count
) == 0)
175 case RPC_PIPEFS_UMOUNT
:
176 if (clnt
->cl_pipedir_objects
.pdh_dentry
== NULL
)
183 static int __rpc_clnt_handle_event(struct rpc_clnt
*clnt
, unsigned long event
,
184 struct super_block
*sb
)
186 struct dentry
*dentry
;
190 case RPC_PIPEFS_MOUNT
:
191 dentry
= rpc_setup_pipedir_sb(sb
, clnt
);
195 return PTR_ERR(dentry
);
197 case RPC_PIPEFS_UMOUNT
:
198 __rpc_clnt_remove_pipedir(clnt
);
201 printk(KERN_ERR
"%s: unknown event: %ld\n", __func__
, event
);
207 static int __rpc_pipefs_event(struct rpc_clnt
*clnt
, unsigned long event
,
208 struct super_block
*sb
)
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
)
221 static struct rpc_clnt
*rpc_get_client_for_event(struct net
*net
, int event
)
223 struct sunrpc_net
*sn
= net_generic(net
, sunrpc_net_id
);
224 struct rpc_clnt
*clnt
;
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
))
230 spin_unlock(&sn
->rpc_client_lock
);
233 spin_unlock(&sn
->rpc_client_lock
);
237 static int rpc_pipefs_event(struct notifier_block
*nb
, unsigned long event
,
240 struct super_block
*sb
= ptr
;
241 struct rpc_clnt
*clnt
;
244 while ((clnt
= rpc_get_client_for_event(sb
->s_fs_info
, event
))) {
245 error
= __rpc_pipefs_event(clnt
, event
, sb
);
252 static struct notifier_block rpc_clients_block
= {
253 .notifier_call
= rpc_pipefs_event
,
254 .priority
= SUNRPC_PIPEFS_RPC_PRIO
,
257 int rpc_clients_notifier_register(void)
259 return rpc_pipefs_notifier_register(&rpc_clients_block
);
262 void rpc_clients_notifier_unregister(void)
264 return rpc_pipefs_notifier_unregister(&rpc_clients_block
);
267 static struct rpc_xprt
*rpc_clnt_set_transport(struct rpc_clnt
*clnt
,
268 struct rpc_xprt
*xprt
,
269 const struct rpc_timeout
*timeout
)
271 struct rpc_xprt
*old
;
273 spin_lock(&clnt
->cl_lock
);
274 old
= rcu_dereference_protected(clnt
->cl_xprt
,
275 lockdep_is_held(&clnt
->cl_lock
));
277 if (!xprt_bound(xprt
))
278 clnt
->cl_autobind
= 1;
280 clnt
->cl_timeout
= timeout
;
281 rcu_assign_pointer(clnt
->cl_xprt
, xprt
);
282 spin_unlock(&clnt
->cl_lock
);
287 static void rpc_clnt_set_nodename(struct rpc_clnt
*clnt
, const char *nodename
)
289 clnt
->cl_nodelen
= strlcpy(clnt
->cl_nodename
,
290 nodename
, sizeof(clnt
->cl_nodename
));
293 static int rpc_client_register(struct rpc_clnt
*clnt
,
294 rpc_authflavor_t pseudoflavor
,
295 const char *client_name
)
297 struct rpc_auth_create_args auth_args
= {
298 .pseudoflavor
= pseudoflavor
,
299 .target_name
= client_name
,
301 struct rpc_auth
*auth
;
302 struct net
*net
= rpc_net_ns(clnt
);
303 struct super_block
*pipefs_sb
;
306 rpc_clnt_debugfs_register(clnt
);
308 pipefs_sb
= rpc_get_sb_net(net
);
310 err
= rpc_setup_pipedir(pipefs_sb
, clnt
);
315 rpc_register_client(clnt
);
319 auth
= rpcauth_create(&auth_args
, clnt
);
321 dprintk("RPC: Couldn't create auth handle (flavor %u)\n",
328 pipefs_sb
= rpc_get_sb_net(net
);
329 rpc_unregister_client(clnt
);
330 __rpc_clnt_remove_pipedir(clnt
);
334 rpc_clnt_debugfs_unregister(clnt
);
338 static DEFINE_IDA(rpc_clids
);
340 static int rpc_alloc_clid(struct rpc_clnt
*clnt
)
344 clid
= ida_simple_get(&rpc_clids
, 0, 0, GFP_KERNEL
);
347 clnt
->cl_clid
= clid
;
351 static void rpc_free_clid(struct rpc_clnt
*clnt
)
353 ida_simple_remove(&rpc_clids
, clnt
->cl_clid
);
356 static struct rpc_clnt
* rpc_new_client(const struct rpc_create_args
*args
,
357 struct rpc_xprt
*xprt
,
358 struct rpc_clnt
*parent
)
360 const struct rpc_program
*program
= args
->program
;
361 const struct rpc_version
*version
;
362 struct rpc_clnt
*clnt
= NULL
;
363 const struct rpc_timeout
*timeout
;
364 const char *nodename
= args
->nodename
;
367 /* sanity check the name before trying to print it */
368 dprintk("RPC: creating %s client for %s (xprt %p)\n",
369 program
->name
, args
->servername
, xprt
);
376 if (args
->version
>= program
->nrvers
)
378 version
= program
->version
[args
->version
];
383 clnt
= kzalloc(sizeof(*clnt
), GFP_KERNEL
);
386 clnt
->cl_parent
= parent
? : clnt
;
388 err
= rpc_alloc_clid(clnt
);
392 clnt
->cl_procinfo
= version
->procs
;
393 clnt
->cl_maxproc
= version
->nrprocs
;
394 clnt
->cl_prog
= args
->prognumber
? : program
->number
;
395 clnt
->cl_vers
= version
->number
;
396 clnt
->cl_stats
= program
->stats
;
397 clnt
->cl_metrics
= rpc_alloc_iostats(clnt
);
398 rpc_init_pipe_dir_head(&clnt
->cl_pipedir_objects
);
400 if (clnt
->cl_metrics
== NULL
)
402 clnt
->cl_program
= program
;
403 INIT_LIST_HEAD(&clnt
->cl_tasks
);
404 spin_lock_init(&clnt
->cl_lock
);
406 timeout
= xprt
->timeout
;
407 if (args
->timeout
!= NULL
) {
408 memcpy(&clnt
->cl_timeout_default
, args
->timeout
,
409 sizeof(clnt
->cl_timeout_default
));
410 timeout
= &clnt
->cl_timeout_default
;
413 rpc_clnt_set_transport(clnt
, xprt
, timeout
);
415 clnt
->cl_rtt
= &clnt
->cl_rtt_default
;
416 rpc_init_rtt(&clnt
->cl_rtt_default
, clnt
->cl_timeout
->to_initval
);
418 atomic_set(&clnt
->cl_count
, 1);
420 if (nodename
== NULL
)
421 nodename
= utsname()->nodename
;
422 /* save the nodename */
423 rpc_clnt_set_nodename(clnt
, nodename
);
425 err
= rpc_client_register(clnt
, args
->authflavor
, args
->client_name
);
429 atomic_inc(&parent
->cl_count
);
433 rpc_free_iostats(clnt
->cl_metrics
);
445 struct rpc_clnt
*rpc_create_xprt(struct rpc_create_args
*args
,
446 struct rpc_xprt
*xprt
)
448 struct rpc_clnt
*clnt
= NULL
;
450 clnt
= rpc_new_client(args
, xprt
, NULL
);
454 if (!(args
->flags
& RPC_CLNT_CREATE_NOPING
)) {
455 int err
= rpc_ping(clnt
);
457 rpc_shutdown_client(clnt
);
462 clnt
->cl_softrtry
= 1;
463 if (args
->flags
& RPC_CLNT_CREATE_HARDRTRY
)
464 clnt
->cl_softrtry
= 0;
466 if (args
->flags
& RPC_CLNT_CREATE_AUTOBIND
)
467 clnt
->cl_autobind
= 1;
468 if (args
->flags
& RPC_CLNT_CREATE_NO_RETRANS_TIMEOUT
)
469 clnt
->cl_noretranstimeo
= 1;
470 if (args
->flags
& RPC_CLNT_CREATE_DISCRTRY
)
471 clnt
->cl_discrtry
= 1;
472 if (!(args
->flags
& RPC_CLNT_CREATE_QUIET
))
477 EXPORT_SYMBOL_GPL(rpc_create_xprt
);
480 * rpc_create - create an RPC client and transport with one call
481 * @args: rpc_clnt create argument structure
483 * Creates and initializes an RPC transport and an RPC client.
485 * It can ping the server in order to determine if it is up, and to see if
486 * it supports this program and version. RPC_CLNT_CREATE_NOPING disables
487 * this behavior so asynchronous tasks can also use rpc_create.
489 struct rpc_clnt
*rpc_create(struct rpc_create_args
*args
)
491 struct rpc_xprt
*xprt
;
492 struct xprt_create xprtargs
= {
494 .ident
= args
->protocol
,
495 .srcaddr
= args
->saddress
,
496 .dstaddr
= args
->address
,
497 .addrlen
= args
->addrsize
,
498 .servername
= args
->servername
,
499 .bc_xprt
= args
->bc_xprt
,
503 if (args
->flags
& RPC_CLNT_CREATE_INFINITE_SLOTS
)
504 xprtargs
.flags
|= XPRT_CREATE_INFINITE_SLOTS
;
505 if (args
->flags
& RPC_CLNT_CREATE_NO_IDLE_TIMEOUT
)
506 xprtargs
.flags
|= XPRT_CREATE_NO_IDLE_TIMEOUT
;
508 * If the caller chooses not to specify a hostname, whip
509 * up a string representation of the passed-in address.
511 if (xprtargs
.servername
== NULL
) {
512 struct sockaddr_un
*sun
=
513 (struct sockaddr_un
*)args
->address
;
514 struct sockaddr_in
*sin
=
515 (struct sockaddr_in
*)args
->address
;
516 struct sockaddr_in6
*sin6
=
517 (struct sockaddr_in6
*)args
->address
;
519 servername
[0] = '\0';
520 switch (args
->address
->sa_family
) {
522 snprintf(servername
, sizeof(servername
), "%s",
526 snprintf(servername
, sizeof(servername
), "%pI4",
527 &sin
->sin_addr
.s_addr
);
530 snprintf(servername
, sizeof(servername
), "%pI6",
534 /* caller wants default server name, but
535 * address family isn't recognized. */
536 return ERR_PTR(-EINVAL
);
538 xprtargs
.servername
= servername
;
541 xprt
= xprt_create_transport(&xprtargs
);
543 return (struct rpc_clnt
*)xprt
;
546 * By default, kernel RPC client connects from a reserved port.
547 * CAP_NET_BIND_SERVICE will not be set for unprivileged requesters,
548 * but it is always enabled for rpciod, which handles the connect
552 if (args
->flags
& RPC_CLNT_CREATE_NONPRIVPORT
)
555 return rpc_create_xprt(args
, xprt
);
557 EXPORT_SYMBOL_GPL(rpc_create
);
560 * This function clones the RPC client structure. It allows us to share the
561 * same transport while varying parameters such as the authentication
564 static struct rpc_clnt
*__rpc_clone_client(struct rpc_create_args
*args
,
565 struct rpc_clnt
*clnt
)
567 struct rpc_xprt
*xprt
;
568 struct rpc_clnt
*new;
573 xprt
= xprt_get(rcu_dereference(clnt
->cl_xprt
));
577 args
->servername
= xprt
->servername
;
578 args
->nodename
= clnt
->cl_nodename
;
580 new = rpc_new_client(args
, xprt
, clnt
);
586 /* Turn off autobind on clones */
587 new->cl_autobind
= 0;
588 new->cl_softrtry
= clnt
->cl_softrtry
;
589 new->cl_noretranstimeo
= clnt
->cl_noretranstimeo
;
590 new->cl_discrtry
= clnt
->cl_discrtry
;
591 new->cl_chatty
= clnt
->cl_chatty
;
595 dprintk("RPC: %s: returned error %d\n", __func__
, err
);
600 * rpc_clone_client - Clone an RPC client structure
602 * @clnt: RPC client whose parameters are copied
604 * Returns a fresh RPC client or an ERR_PTR.
606 struct rpc_clnt
*rpc_clone_client(struct rpc_clnt
*clnt
)
608 struct rpc_create_args args
= {
609 .program
= clnt
->cl_program
,
610 .prognumber
= clnt
->cl_prog
,
611 .version
= clnt
->cl_vers
,
612 .authflavor
= clnt
->cl_auth
->au_flavor
,
614 return __rpc_clone_client(&args
, clnt
);
616 EXPORT_SYMBOL_GPL(rpc_clone_client
);
619 * rpc_clone_client_set_auth - Clone an RPC client structure and set its auth
621 * @clnt: RPC client whose parameters are copied
622 * @flavor: security flavor for new client
624 * Returns a fresh RPC client or an ERR_PTR.
627 rpc_clone_client_set_auth(struct rpc_clnt
*clnt
, rpc_authflavor_t flavor
)
629 struct rpc_create_args args
= {
630 .program
= clnt
->cl_program
,
631 .prognumber
= clnt
->cl_prog
,
632 .version
= clnt
->cl_vers
,
633 .authflavor
= flavor
,
635 return __rpc_clone_client(&args
, clnt
);
637 EXPORT_SYMBOL_GPL(rpc_clone_client_set_auth
);
640 * rpc_switch_client_transport: switch the RPC transport on the fly
641 * @clnt: pointer to a struct rpc_clnt
642 * @args: pointer to the new transport arguments
643 * @timeout: pointer to the new timeout parameters
645 * This function allows the caller to switch the RPC transport for the
646 * rpc_clnt structure 'clnt' to allow it to connect to a mirrored NFS
647 * server, for instance. It assumes that the caller has ensured that
648 * there are no active RPC tasks by using some form of locking.
650 * Returns zero if "clnt" is now using the new xprt. Otherwise a
651 * negative errno is returned, and "clnt" continues to use the old
654 int rpc_switch_client_transport(struct rpc_clnt
*clnt
,
655 struct xprt_create
*args
,
656 const struct rpc_timeout
*timeout
)
658 const struct rpc_timeout
*old_timeo
;
659 rpc_authflavor_t pseudoflavor
;
660 struct rpc_xprt
*xprt
, *old
;
661 struct rpc_clnt
*parent
;
664 xprt
= xprt_create_transport(args
);
666 dprintk("RPC: failed to create new xprt for clnt %p\n",
668 return PTR_ERR(xprt
);
671 pseudoflavor
= clnt
->cl_auth
->au_flavor
;
673 old_timeo
= clnt
->cl_timeout
;
674 old
= rpc_clnt_set_transport(clnt
, xprt
, timeout
);
676 rpc_unregister_client(clnt
);
677 __rpc_clnt_remove_pipedir(clnt
);
678 rpc_clnt_debugfs_unregister(clnt
);
681 * A new transport was created. "clnt" therefore
682 * becomes the root of a new cl_parent tree. clnt's
683 * children, if it has any, still point to the old xprt.
685 parent
= clnt
->cl_parent
;
686 clnt
->cl_parent
= clnt
;
689 * The old rpc_auth cache cannot be re-used. GSS
690 * contexts in particular are between a single
693 err
= rpc_client_register(clnt
, pseudoflavor
, NULL
);
699 rpc_release_client(parent
);
701 dprintk("RPC: replaced xprt for clnt %p\n", clnt
);
705 rpc_clnt_set_transport(clnt
, old
, old_timeo
);
706 clnt
->cl_parent
= parent
;
707 rpc_client_register(clnt
, pseudoflavor
, NULL
);
709 dprintk("RPC: failed to switch xprt for clnt %p\n", clnt
);
712 EXPORT_SYMBOL_GPL(rpc_switch_client_transport
);
715 * Kill all tasks for the given client.
716 * XXX: kill their descendants as well?
718 void rpc_killall_tasks(struct rpc_clnt
*clnt
)
720 struct rpc_task
*rovr
;
723 if (list_empty(&clnt
->cl_tasks
))
725 dprintk("RPC: killing all tasks for client %p\n", clnt
);
727 * Spin lock all_tasks to prevent changes...
729 spin_lock(&clnt
->cl_lock
);
730 list_for_each_entry(rovr
, &clnt
->cl_tasks
, tk_task
) {
731 if (!RPC_IS_ACTIVATED(rovr
))
733 if (!(rovr
->tk_flags
& RPC_TASK_KILLED
)) {
734 rovr
->tk_flags
|= RPC_TASK_KILLED
;
735 rpc_exit(rovr
, -EIO
);
736 if (RPC_IS_QUEUED(rovr
))
737 rpc_wake_up_queued_task(rovr
->tk_waitqueue
,
741 spin_unlock(&clnt
->cl_lock
);
743 EXPORT_SYMBOL_GPL(rpc_killall_tasks
);
746 * Properly shut down an RPC client, terminating all outstanding
749 void rpc_shutdown_client(struct rpc_clnt
*clnt
)
753 dprintk_rcu("RPC: shutting down %s client for %s\n",
754 clnt
->cl_program
->name
,
755 rcu_dereference(clnt
->cl_xprt
)->servername
);
757 while (!list_empty(&clnt
->cl_tasks
)) {
758 rpc_killall_tasks(clnt
);
759 wait_event_timeout(destroy_wait
,
760 list_empty(&clnt
->cl_tasks
), 1*HZ
);
763 rpc_release_client(clnt
);
765 EXPORT_SYMBOL_GPL(rpc_shutdown_client
);
770 static struct rpc_clnt
*
771 rpc_free_client(struct rpc_clnt
*clnt
)
773 struct rpc_clnt
*parent
= NULL
;
775 dprintk_rcu("RPC: destroying %s client for %s\n",
776 clnt
->cl_program
->name
,
777 rcu_dereference(clnt
->cl_xprt
)->servername
);
778 if (clnt
->cl_parent
!= clnt
)
779 parent
= clnt
->cl_parent
;
780 rpc_clnt_debugfs_unregister(clnt
);
781 rpc_clnt_remove_pipedir(clnt
);
782 rpc_unregister_client(clnt
);
783 rpc_free_iostats(clnt
->cl_metrics
);
784 clnt
->cl_metrics
= NULL
;
785 xprt_put(rcu_dereference_raw(clnt
->cl_xprt
));
795 static struct rpc_clnt
*
796 rpc_free_auth(struct rpc_clnt
*clnt
)
798 if (clnt
->cl_auth
== NULL
)
799 return rpc_free_client(clnt
);
802 * Note: RPCSEC_GSS may need to send NULL RPC calls in order to
803 * release remaining GSS contexts. This mechanism ensures
804 * that it can do so safely.
806 atomic_inc(&clnt
->cl_count
);
807 rpcauth_release(clnt
->cl_auth
);
808 clnt
->cl_auth
= NULL
;
809 if (atomic_dec_and_test(&clnt
->cl_count
))
810 return rpc_free_client(clnt
);
815 * Release reference to the RPC client
818 rpc_release_client(struct rpc_clnt
*clnt
)
820 dprintk("RPC: rpc_release_client(%p)\n", clnt
);
823 if (list_empty(&clnt
->cl_tasks
))
824 wake_up(&destroy_wait
);
825 if (!atomic_dec_and_test(&clnt
->cl_count
))
827 clnt
= rpc_free_auth(clnt
);
828 } while (clnt
!= NULL
);
830 EXPORT_SYMBOL_GPL(rpc_release_client
);
833 * rpc_bind_new_program - bind a new RPC program to an existing client
834 * @old: old rpc_client
835 * @program: rpc program to set
836 * @vers: rpc program version
838 * Clones the rpc client and sets up a new RPC program. This is mainly
839 * of use for enabling different RPC programs to share the same transport.
840 * The Sun NFSv2/v3 ACL protocol can do this.
842 struct rpc_clnt
*rpc_bind_new_program(struct rpc_clnt
*old
,
843 const struct rpc_program
*program
,
846 struct rpc_create_args args
= {
848 .prognumber
= program
->number
,
850 .authflavor
= old
->cl_auth
->au_flavor
,
852 struct rpc_clnt
*clnt
;
855 clnt
= __rpc_clone_client(&args
, old
);
858 err
= rpc_ping(clnt
);
860 rpc_shutdown_client(clnt
);
866 EXPORT_SYMBOL_GPL(rpc_bind_new_program
);
868 void rpc_task_release_client(struct rpc_task
*task
)
870 struct rpc_clnt
*clnt
= task
->tk_client
;
873 /* Remove from client task list */
874 spin_lock(&clnt
->cl_lock
);
875 list_del(&task
->tk_task
);
876 spin_unlock(&clnt
->cl_lock
);
877 task
->tk_client
= NULL
;
879 rpc_release_client(clnt
);
884 void rpc_task_set_client(struct rpc_task
*task
, struct rpc_clnt
*clnt
)
887 rpc_task_release_client(task
);
888 task
->tk_client
= clnt
;
889 atomic_inc(&clnt
->cl_count
);
890 if (clnt
->cl_softrtry
)
891 task
->tk_flags
|= RPC_TASK_SOFT
;
892 if (clnt
->cl_noretranstimeo
)
893 task
->tk_flags
|= RPC_TASK_NO_RETRANS_TIMEOUT
;
894 if (atomic_read(&clnt
->cl_swapper
))
895 task
->tk_flags
|= RPC_TASK_SWAPPER
;
896 /* Add to the client's list of all tasks */
897 spin_lock(&clnt
->cl_lock
);
898 list_add_tail(&task
->tk_task
, &clnt
->cl_tasks
);
899 spin_unlock(&clnt
->cl_lock
);
903 void rpc_task_reset_client(struct rpc_task
*task
, struct rpc_clnt
*clnt
)
905 rpc_task_release_client(task
);
906 rpc_task_set_client(task
, clnt
);
908 EXPORT_SYMBOL_GPL(rpc_task_reset_client
);
912 rpc_task_set_rpc_message(struct rpc_task
*task
, const struct rpc_message
*msg
)
915 task
->tk_msg
.rpc_proc
= msg
->rpc_proc
;
916 task
->tk_msg
.rpc_argp
= msg
->rpc_argp
;
917 task
->tk_msg
.rpc_resp
= msg
->rpc_resp
;
918 if (msg
->rpc_cred
!= NULL
)
919 task
->tk_msg
.rpc_cred
= get_rpccred(msg
->rpc_cred
);
924 * Default callback for async RPC calls
927 rpc_default_callback(struct rpc_task
*task
, void *data
)
931 static const struct rpc_call_ops rpc_default_ops
= {
932 .rpc_call_done
= rpc_default_callback
,
936 * rpc_run_task - Allocate a new RPC task, then run rpc_execute against it
937 * @task_setup_data: pointer to task initialisation data
939 struct rpc_task
*rpc_run_task(const struct rpc_task_setup
*task_setup_data
)
941 struct rpc_task
*task
;
943 task
= rpc_new_task(task_setup_data
);
947 rpc_task_set_client(task
, task_setup_data
->rpc_client
);
948 rpc_task_set_rpc_message(task
, task_setup_data
->rpc_message
);
950 if (task
->tk_action
== NULL
)
951 rpc_call_start(task
);
953 atomic_inc(&task
->tk_count
);
958 EXPORT_SYMBOL_GPL(rpc_run_task
);
961 * rpc_call_sync - Perform a synchronous RPC call
962 * @clnt: pointer to RPC client
963 * @msg: RPC call parameters
964 * @flags: RPC call flags
966 int rpc_call_sync(struct rpc_clnt
*clnt
, const struct rpc_message
*msg
, int flags
)
968 struct rpc_task
*task
;
969 struct rpc_task_setup task_setup_data
= {
972 .callback_ops
= &rpc_default_ops
,
977 WARN_ON_ONCE(flags
& RPC_TASK_ASYNC
);
978 if (flags
& RPC_TASK_ASYNC
) {
979 rpc_release_calldata(task_setup_data
.callback_ops
,
980 task_setup_data
.callback_data
);
984 task
= rpc_run_task(&task_setup_data
);
986 return PTR_ERR(task
);
987 status
= task
->tk_status
;
991 EXPORT_SYMBOL_GPL(rpc_call_sync
);
994 * rpc_call_async - Perform an asynchronous RPC call
995 * @clnt: pointer to RPC client
996 * @msg: RPC call parameters
997 * @flags: RPC call flags
998 * @tk_ops: RPC call ops
999 * @data: user call data
1002 rpc_call_async(struct rpc_clnt
*clnt
, const struct rpc_message
*msg
, int flags
,
1003 const struct rpc_call_ops
*tk_ops
, void *data
)
1005 struct rpc_task
*task
;
1006 struct rpc_task_setup task_setup_data
= {
1009 .callback_ops
= tk_ops
,
1010 .callback_data
= data
,
1011 .flags
= flags
|RPC_TASK_ASYNC
,
1014 task
= rpc_run_task(&task_setup_data
);
1016 return PTR_ERR(task
);
1020 EXPORT_SYMBOL_GPL(rpc_call_async
);
1022 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1024 * rpc_run_bc_task - Allocate a new RPC task for backchannel use, then run
1025 * rpc_execute against it
1028 struct rpc_task
*rpc_run_bc_task(struct rpc_rqst
*req
)
1030 struct rpc_task
*task
;
1031 struct xdr_buf
*xbufp
= &req
->rq_snd_buf
;
1032 struct rpc_task_setup task_setup_data
= {
1033 .callback_ops
= &rpc_default_ops
,
1034 .flags
= RPC_TASK_SOFTCONN
,
1037 dprintk("RPC: rpc_run_bc_task req= %p\n", req
);
1039 * Create an rpc_task to send the data
1041 task
= rpc_new_task(&task_setup_data
);
1043 xprt_free_bc_request(req
);
1046 task
->tk_rqstp
= req
;
1049 * Set up the xdr_buf length.
1050 * This also indicates that the buffer is XDR encoded already.
1052 xbufp
->len
= xbufp
->head
[0].iov_len
+ xbufp
->page_len
+
1053 xbufp
->tail
[0].iov_len
;
1055 task
->tk_action
= call_bc_transmit
;
1056 atomic_inc(&task
->tk_count
);
1057 WARN_ON_ONCE(atomic_read(&task
->tk_count
) != 2);
1061 dprintk("RPC: rpc_run_bc_task: task= %p\n", task
);
1064 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1067 rpc_call_start(struct rpc_task
*task
)
1069 task
->tk_action
= call_start
;
1071 EXPORT_SYMBOL_GPL(rpc_call_start
);
1074 * rpc_peeraddr - extract remote peer address from clnt's xprt
1075 * @clnt: RPC client structure
1076 * @buf: target buffer
1077 * @bufsize: length of target buffer
1079 * Returns the number of bytes that are actually in the stored address.
1081 size_t rpc_peeraddr(struct rpc_clnt
*clnt
, struct sockaddr
*buf
, size_t bufsize
)
1084 struct rpc_xprt
*xprt
;
1087 xprt
= rcu_dereference(clnt
->cl_xprt
);
1089 bytes
= xprt
->addrlen
;
1090 if (bytes
> bufsize
)
1092 memcpy(buf
, &xprt
->addr
, bytes
);
1097 EXPORT_SYMBOL_GPL(rpc_peeraddr
);
1100 * rpc_peeraddr2str - return remote peer address in printable format
1101 * @clnt: RPC client structure
1102 * @format: address format
1104 * NB: the lifetime of the memory referenced by the returned pointer is
1105 * the same as the rpc_xprt itself. As long as the caller uses this
1106 * pointer, it must hold the RCU read lock.
1108 const char *rpc_peeraddr2str(struct rpc_clnt
*clnt
,
1109 enum rpc_display_format_t format
)
1111 struct rpc_xprt
*xprt
;
1113 xprt
= rcu_dereference(clnt
->cl_xprt
);
1115 if (xprt
->address_strings
[format
] != NULL
)
1116 return xprt
->address_strings
[format
];
1118 return "unprintable";
1120 EXPORT_SYMBOL_GPL(rpc_peeraddr2str
);
1122 static const struct sockaddr_in rpc_inaddr_loopback
= {
1123 .sin_family
= AF_INET
,
1124 .sin_addr
.s_addr
= htonl(INADDR_ANY
),
1127 static const struct sockaddr_in6 rpc_in6addr_loopback
= {
1128 .sin6_family
= AF_INET6
,
1129 .sin6_addr
= IN6ADDR_ANY_INIT
,
1133 * Try a getsockname() on a connected datagram socket. Using a
1134 * connected datagram socket prevents leaving a socket in TIME_WAIT.
1135 * This conserves the ephemeral port number space.
1137 * Returns zero and fills in "buf" if successful; otherwise, a
1138 * negative errno is returned.
1140 static int rpc_sockname(struct net
*net
, struct sockaddr
*sap
, size_t salen
,
1141 struct sockaddr
*buf
, int buflen
)
1143 struct socket
*sock
;
1146 err
= __sock_create(net
, sap
->sa_family
,
1147 SOCK_DGRAM
, IPPROTO_UDP
, &sock
, 1);
1149 dprintk("RPC: can't create UDP socket (%d)\n", err
);
1153 switch (sap
->sa_family
) {
1155 err
= kernel_bind(sock
,
1156 (struct sockaddr
*)&rpc_inaddr_loopback
,
1157 sizeof(rpc_inaddr_loopback
));
1160 err
= kernel_bind(sock
,
1161 (struct sockaddr
*)&rpc_in6addr_loopback
,
1162 sizeof(rpc_in6addr_loopback
));
1165 err
= -EAFNOSUPPORT
;
1169 dprintk("RPC: can't bind UDP socket (%d)\n", err
);
1173 err
= kernel_connect(sock
, sap
, salen
, 0);
1175 dprintk("RPC: can't connect UDP socket (%d)\n", err
);
1179 err
= kernel_getsockname(sock
, buf
, &buflen
);
1181 dprintk("RPC: getsockname failed (%d)\n", err
);
1186 if (buf
->sa_family
== AF_INET6
) {
1187 struct sockaddr_in6
*sin6
= (struct sockaddr_in6
*)buf
;
1188 sin6
->sin6_scope_id
= 0;
1190 dprintk("RPC: %s succeeded\n", __func__
);
1199 * Scraping a connected socket failed, so we don't have a useable
1200 * local address. Fallback: generate an address that will prevent
1201 * the server from calling us back.
1203 * Returns zero and fills in "buf" if successful; otherwise, a
1204 * negative errno is returned.
1206 static int rpc_anyaddr(int family
, struct sockaddr
*buf
, size_t buflen
)
1210 if (buflen
< sizeof(rpc_inaddr_loopback
))
1212 memcpy(buf
, &rpc_inaddr_loopback
,
1213 sizeof(rpc_inaddr_loopback
));
1216 if (buflen
< sizeof(rpc_in6addr_loopback
))
1218 memcpy(buf
, &rpc_in6addr_loopback
,
1219 sizeof(rpc_in6addr_loopback
));
1222 dprintk("RPC: %s: address family not supported\n",
1224 return -EAFNOSUPPORT
;
1226 dprintk("RPC: %s: succeeded\n", __func__
);
1231 * rpc_localaddr - discover local endpoint address for an RPC client
1232 * @clnt: RPC client structure
1233 * @buf: target buffer
1234 * @buflen: size of target buffer, in bytes
1236 * Returns zero and fills in "buf" and "buflen" if successful;
1237 * otherwise, a negative errno is returned.
1239 * This works even if the underlying transport is not currently connected,
1240 * or if the upper layer never previously provided a source address.
1242 * The result of this function call is transient: multiple calls in
1243 * succession may give different results, depending on how local
1244 * networking configuration changes over time.
1246 int rpc_localaddr(struct rpc_clnt
*clnt
, struct sockaddr
*buf
, size_t buflen
)
1248 struct sockaddr_storage address
;
1249 struct sockaddr
*sap
= (struct sockaddr
*)&address
;
1250 struct rpc_xprt
*xprt
;
1256 xprt
= rcu_dereference(clnt
->cl_xprt
);
1257 salen
= xprt
->addrlen
;
1258 memcpy(sap
, &xprt
->addr
, salen
);
1259 net
= get_net(xprt
->xprt_net
);
1262 rpc_set_port(sap
, 0);
1263 err
= rpc_sockname(net
, sap
, salen
, buf
, buflen
);
1266 /* Couldn't discover local address, return ANYADDR */
1267 return rpc_anyaddr(sap
->sa_family
, buf
, buflen
);
1270 EXPORT_SYMBOL_GPL(rpc_localaddr
);
1273 rpc_setbufsize(struct rpc_clnt
*clnt
, unsigned int sndsize
, unsigned int rcvsize
)
1275 struct rpc_xprt
*xprt
;
1278 xprt
= rcu_dereference(clnt
->cl_xprt
);
1279 if (xprt
->ops
->set_buffer_size
)
1280 xprt
->ops
->set_buffer_size(xprt
, sndsize
, rcvsize
);
1283 EXPORT_SYMBOL_GPL(rpc_setbufsize
);
1286 * rpc_protocol - Get transport protocol number for an RPC client
1287 * @clnt: RPC client to query
1290 int rpc_protocol(struct rpc_clnt
*clnt
)
1295 protocol
= rcu_dereference(clnt
->cl_xprt
)->prot
;
1299 EXPORT_SYMBOL_GPL(rpc_protocol
);
1302 * rpc_net_ns - Get the network namespace for this RPC client
1303 * @clnt: RPC client to query
1306 struct net
*rpc_net_ns(struct rpc_clnt
*clnt
)
1311 ret
= rcu_dereference(clnt
->cl_xprt
)->xprt_net
;
1315 EXPORT_SYMBOL_GPL(rpc_net_ns
);
1318 * rpc_max_payload - Get maximum payload size for a transport, in bytes
1319 * @clnt: RPC client to query
1321 * For stream transports, this is one RPC record fragment (see RFC
1322 * 1831), as we don't support multi-record requests yet. For datagram
1323 * transports, this is the size of an IP packet minus the IP, UDP, and
1326 size_t rpc_max_payload(struct rpc_clnt
*clnt
)
1331 ret
= rcu_dereference(clnt
->cl_xprt
)->max_payload
;
1335 EXPORT_SYMBOL_GPL(rpc_max_payload
);
1338 * rpc_get_timeout - Get timeout for transport in units of HZ
1339 * @clnt: RPC client to query
1341 unsigned long rpc_get_timeout(struct rpc_clnt
*clnt
)
1346 ret
= rcu_dereference(clnt
->cl_xprt
)->timeout
->to_initval
;
1350 EXPORT_SYMBOL_GPL(rpc_get_timeout
);
1353 * rpc_force_rebind - force transport to check that remote port is unchanged
1354 * @clnt: client to rebind
1357 void rpc_force_rebind(struct rpc_clnt
*clnt
)
1359 if (clnt
->cl_autobind
) {
1361 xprt_clear_bound(rcu_dereference(clnt
->cl_xprt
));
1365 EXPORT_SYMBOL_GPL(rpc_force_rebind
);
1368 * Restart an (async) RPC call from the call_prepare state.
1369 * Usually called from within the exit handler.
1372 rpc_restart_call_prepare(struct rpc_task
*task
)
1374 if (RPC_ASSASSINATED(task
))
1376 task
->tk_action
= call_start
;
1377 task
->tk_status
= 0;
1378 if (task
->tk_ops
->rpc_call_prepare
!= NULL
)
1379 task
->tk_action
= rpc_prepare_task
;
1382 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare
);
1385 * Restart an (async) RPC call. Usually called from within the
1389 rpc_restart_call(struct rpc_task
*task
)
1391 if (RPC_ASSASSINATED(task
))
1393 task
->tk_action
= call_start
;
1394 task
->tk_status
= 0;
1397 EXPORT_SYMBOL_GPL(rpc_restart_call
);
1399 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
1401 *rpc_proc_name(const struct rpc_task
*task
)
1403 const struct rpc_procinfo
*proc
= task
->tk_msg
.rpc_proc
;
1407 return proc
->p_name
;
1418 * Other FSM states can be visited zero or more times, but
1419 * this state is visited exactly once for each RPC.
1422 call_start(struct rpc_task
*task
)
1424 struct rpc_clnt
*clnt
= task
->tk_client
;
1426 dprintk("RPC: %5u call_start %s%d proc %s (%s)\n", task
->tk_pid
,
1427 clnt
->cl_program
->name
, clnt
->cl_vers
,
1428 rpc_proc_name(task
),
1429 (RPC_IS_ASYNC(task
) ? "async" : "sync"));
1431 /* Increment call count */
1432 task
->tk_msg
.rpc_proc
->p_count
++;
1433 clnt
->cl_stats
->rpccnt
++;
1434 task
->tk_action
= call_reserve
;
1438 * 1. Reserve an RPC call slot
1441 call_reserve(struct rpc_task
*task
)
1443 dprint_status(task
);
1445 task
->tk_status
= 0;
1446 task
->tk_action
= call_reserveresult
;
1450 static void call_retry_reserve(struct rpc_task
*task
);
1453 * 1b. Grok the result of xprt_reserve()
1456 call_reserveresult(struct rpc_task
*task
)
1458 int status
= task
->tk_status
;
1460 dprint_status(task
);
1463 * After a call to xprt_reserve(), we must have either
1464 * a request slot or else an error status.
1466 task
->tk_status
= 0;
1468 if (task
->tk_rqstp
) {
1469 task
->tk_action
= call_refresh
;
1473 printk(KERN_ERR
"%s: status=%d, but no request slot, exiting\n",
1475 rpc_exit(task
, -EIO
);
1480 * Even though there was an error, we may have acquired
1481 * a request slot somehow. Make sure not to leak it.
1483 if (task
->tk_rqstp
) {
1484 printk(KERN_ERR
"%s: status=%d, request allocated anyway\n",
1491 rpc_delay(task
, HZ
>> 2);
1492 case -EAGAIN
: /* woken up; retry */
1493 task
->tk_action
= call_retry_reserve
;
1495 case -EIO
: /* probably a shutdown */
1498 printk(KERN_ERR
"%s: unrecognized error %d, exiting\n",
1502 rpc_exit(task
, status
);
1506 * 1c. Retry reserving an RPC call slot
1509 call_retry_reserve(struct rpc_task
*task
)
1511 dprint_status(task
);
1513 task
->tk_status
= 0;
1514 task
->tk_action
= call_reserveresult
;
1515 xprt_retry_reserve(task
);
1519 * 2. Bind and/or refresh the credentials
1522 call_refresh(struct rpc_task
*task
)
1524 dprint_status(task
);
1526 task
->tk_action
= call_refreshresult
;
1527 task
->tk_status
= 0;
1528 task
->tk_client
->cl_stats
->rpcauthrefresh
++;
1529 rpcauth_refreshcred(task
);
1533 * 2a. Process the results of a credential refresh
1536 call_refreshresult(struct rpc_task
*task
)
1538 int status
= task
->tk_status
;
1540 dprint_status(task
);
1542 task
->tk_status
= 0;
1543 task
->tk_action
= call_refresh
;
1546 if (rpcauth_uptodatecred(task
)) {
1547 task
->tk_action
= call_allocate
;
1550 /* Use rate-limiting and a max number of retries if refresh
1551 * had status 0 but failed to update the cred.
1554 rpc_delay(task
, 3*HZ
);
1558 if (!task
->tk_cred_retry
)
1560 task
->tk_cred_retry
--;
1561 dprintk("RPC: %5u %s: retry refresh creds\n",
1562 task
->tk_pid
, __func__
);
1565 dprintk("RPC: %5u %s: refresh creds failed with error %d\n",
1566 task
->tk_pid
, __func__
, status
);
1567 rpc_exit(task
, status
);
1571 * 2b. Allocate the buffer. For details, see sched.c:rpc_malloc.
1572 * (Note: buffer memory is freed in xprt_release).
1575 call_allocate(struct rpc_task
*task
)
1577 unsigned int slack
= task
->tk_rqstp
->rq_cred
->cr_auth
->au_cslack
;
1578 struct rpc_rqst
*req
= task
->tk_rqstp
;
1579 struct rpc_xprt
*xprt
= req
->rq_xprt
;
1580 struct rpc_procinfo
*proc
= task
->tk_msg
.rpc_proc
;
1582 dprint_status(task
);
1584 task
->tk_status
= 0;
1585 task
->tk_action
= call_bind
;
1590 if (proc
->p_proc
!= 0) {
1591 BUG_ON(proc
->p_arglen
== 0);
1592 if (proc
->p_decode
!= NULL
)
1593 BUG_ON(proc
->p_replen
== 0);
1597 * Calculate the size (in quads) of the RPC call
1598 * and reply headers, and convert both values
1601 req
->rq_callsize
= RPC_CALLHDRSIZE
+ (slack
<< 1) + proc
->p_arglen
;
1602 req
->rq_callsize
<<= 2;
1603 req
->rq_rcvsize
= RPC_REPHDRSIZE
+ slack
+ proc
->p_replen
;
1604 req
->rq_rcvsize
<<= 2;
1606 req
->rq_buffer
= xprt
->ops
->buf_alloc(task
,
1607 req
->rq_callsize
+ req
->rq_rcvsize
);
1608 if (req
->rq_buffer
!= NULL
)
1610 xprt_inject_disconnect(xprt
);
1612 dprintk("RPC: %5u rpc_buffer allocation failed\n", task
->tk_pid
);
1614 if (RPC_IS_ASYNC(task
) || !fatal_signal_pending(current
)) {
1615 task
->tk_action
= call_allocate
;
1616 rpc_delay(task
, HZ
>>4);
1620 rpc_exit(task
, -ERESTARTSYS
);
1624 rpc_task_need_encode(struct rpc_task
*task
)
1626 return task
->tk_rqstp
->rq_snd_buf
.len
== 0;
1630 rpc_task_force_reencode(struct rpc_task
*task
)
1632 task
->tk_rqstp
->rq_snd_buf
.len
= 0;
1633 task
->tk_rqstp
->rq_bytes_sent
= 0;
1637 rpc_xdr_buf_init(struct xdr_buf
*buf
, void *start
, size_t len
)
1639 buf
->head
[0].iov_base
= start
;
1640 buf
->head
[0].iov_len
= len
;
1641 buf
->tail
[0].iov_len
= 0;
1649 * 3. Encode arguments of an RPC call
1652 rpc_xdr_encode(struct rpc_task
*task
)
1654 struct rpc_rqst
*req
= task
->tk_rqstp
;
1658 dprint_status(task
);
1660 rpc_xdr_buf_init(&req
->rq_snd_buf
,
1663 rpc_xdr_buf_init(&req
->rq_rcv_buf
,
1664 (char *)req
->rq_buffer
+ req
->rq_callsize
,
1667 p
= rpc_encode_header(task
);
1669 printk(KERN_INFO
"RPC: couldn't encode RPC header, exit EIO\n");
1670 rpc_exit(task
, -EIO
);
1674 encode
= task
->tk_msg
.rpc_proc
->p_encode
;
1678 task
->tk_status
= rpcauth_wrap_req(task
, encode
, req
, p
,
1679 task
->tk_msg
.rpc_argp
);
1683 * 4. Get the server port number if not yet set
1686 call_bind(struct rpc_task
*task
)
1688 struct rpc_xprt
*xprt
= task
->tk_rqstp
->rq_xprt
;
1690 dprint_status(task
);
1692 task
->tk_action
= call_connect
;
1693 if (!xprt_bound(xprt
)) {
1694 task
->tk_action
= call_bind_status
;
1695 task
->tk_timeout
= xprt
->bind_timeout
;
1696 xprt
->ops
->rpcbind(task
);
1701 * 4a. Sort out bind result
1704 call_bind_status(struct rpc_task
*task
)
1708 if (task
->tk_status
>= 0) {
1709 dprint_status(task
);
1710 task
->tk_status
= 0;
1711 task
->tk_action
= call_connect
;
1715 trace_rpc_bind_status(task
);
1716 switch (task
->tk_status
) {
1718 dprintk("RPC: %5u rpcbind out of memory\n", task
->tk_pid
);
1719 rpc_delay(task
, HZ
>> 2);
1722 dprintk("RPC: %5u remote rpcbind: RPC program/version "
1723 "unavailable\n", task
->tk_pid
);
1724 /* fail immediately if this is an RPC ping */
1725 if (task
->tk_msg
.rpc_proc
->p_proc
== 0) {
1726 status
= -EOPNOTSUPP
;
1729 if (task
->tk_rebind_retry
== 0)
1731 task
->tk_rebind_retry
--;
1732 rpc_delay(task
, 3*HZ
);
1735 dprintk("RPC: %5u rpcbind request timed out\n",
1739 /* server doesn't support any rpcbind version we know of */
1740 dprintk("RPC: %5u unrecognized remote rpcbind service\n",
1743 case -EPROTONOSUPPORT
:
1744 dprintk("RPC: %5u remote rpcbind version unavailable, retrying\n",
1747 case -ECONNREFUSED
: /* connection problems */
1756 dprintk("RPC: %5u remote rpcbind unreachable: %d\n",
1757 task
->tk_pid
, task
->tk_status
);
1758 if (!RPC_IS_SOFTCONN(task
)) {
1759 rpc_delay(task
, 5*HZ
);
1762 status
= task
->tk_status
;
1765 dprintk("RPC: %5u unrecognized rpcbind error (%d)\n",
1766 task
->tk_pid
, -task
->tk_status
);
1769 rpc_exit(task
, status
);
1773 task
->tk_status
= 0;
1774 task
->tk_action
= call_timeout
;
1778 * 4b. Connect to the RPC server
1781 call_connect(struct rpc_task
*task
)
1783 struct rpc_xprt
*xprt
= task
->tk_rqstp
->rq_xprt
;
1785 dprintk("RPC: %5u call_connect xprt %p %s connected\n",
1787 (xprt_connected(xprt
) ? "is" : "is not"));
1789 task
->tk_action
= call_transmit
;
1790 if (!xprt_connected(xprt
)) {
1791 task
->tk_action
= call_connect_status
;
1792 if (task
->tk_status
< 0)
1794 if (task
->tk_flags
& RPC_TASK_NOCONNECT
) {
1795 rpc_exit(task
, -ENOTCONN
);
1803 * 4c. Sort out connect result
1806 call_connect_status(struct rpc_task
*task
)
1808 struct rpc_clnt
*clnt
= task
->tk_client
;
1809 int status
= task
->tk_status
;
1811 dprint_status(task
);
1813 trace_rpc_connect_status(task
, status
);
1814 task
->tk_status
= 0;
1824 if (RPC_IS_SOFTCONN(task
))
1826 /* retry with existing socket, after a delay */
1827 rpc_delay(task
, 3*HZ
);
1829 /* Check for timeouts before looping back to call_bind */
1831 task
->tk_action
= call_timeout
;
1834 clnt
->cl_stats
->netreconn
++;
1835 task
->tk_action
= call_transmit
;
1838 rpc_exit(task
, status
);
1842 * 5. Transmit the RPC request, and wait for reply
1845 call_transmit(struct rpc_task
*task
)
1847 int is_retrans
= RPC_WAS_SENT(task
);
1849 dprint_status(task
);
1851 task
->tk_action
= call_status
;
1852 if (task
->tk_status
< 0)
1854 if (!xprt_prepare_transmit(task
))
1856 task
->tk_action
= call_transmit_status
;
1857 /* Encode here so that rpcsec_gss can use correct sequence number. */
1858 if (rpc_task_need_encode(task
)) {
1859 rpc_xdr_encode(task
);
1860 /* Did the encode result in an error condition? */
1861 if (task
->tk_status
!= 0) {
1862 /* Was the error nonfatal? */
1863 if (task
->tk_status
== -EAGAIN
)
1864 rpc_delay(task
, HZ
>> 4);
1866 rpc_exit(task
, task
->tk_status
);
1870 xprt_transmit(task
);
1871 if (task
->tk_status
< 0)
1874 task
->tk_client
->cl_stats
->rpcretrans
++;
1876 * On success, ensure that we call xprt_end_transmit() before sleeping
1877 * in order to allow access to the socket to other RPC requests.
1879 call_transmit_status(task
);
1880 if (rpc_reply_expected(task
))
1882 task
->tk_action
= rpc_exit_task
;
1883 rpc_wake_up_queued_task(&task
->tk_rqstp
->rq_xprt
->pending
, task
);
1887 * 5a. Handle cleanup after a transmission
1890 call_transmit_status(struct rpc_task
*task
)
1892 task
->tk_action
= call_status
;
1895 * Common case: success. Force the compiler to put this
1898 if (task
->tk_status
== 0) {
1899 xprt_end_transmit(task
);
1900 rpc_task_force_reencode(task
);
1904 switch (task
->tk_status
) {
1909 dprint_status(task
);
1910 xprt_end_transmit(task
);
1911 rpc_task_force_reencode(task
);
1914 * Special cases: if we've been waiting on the
1915 * socket's write_space() callback, or if the
1916 * socket just returned a connection error,
1917 * then hold onto the transport lock.
1924 if (RPC_IS_SOFTCONN(task
)) {
1925 xprt_end_transmit(task
);
1926 rpc_exit(task
, task
->tk_status
);
1934 rpc_task_force_reencode(task
);
1938 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1940 * 5b. Send the backchannel RPC reply. On error, drop the reply. In
1941 * addition, disconnect on connectivity errors.
1944 call_bc_transmit(struct rpc_task
*task
)
1946 struct rpc_rqst
*req
= task
->tk_rqstp
;
1948 if (!xprt_prepare_transmit(task
))
1951 if (task
->tk_status
< 0) {
1952 printk(KERN_NOTICE
"RPC: Could not send backchannel reply "
1953 "error: %d\n", task
->tk_status
);
1956 if (req
->rq_connect_cookie
!= req
->rq_xprt
->connect_cookie
)
1957 req
->rq_bytes_sent
= 0;
1959 xprt_transmit(task
);
1961 if (task
->tk_status
== -EAGAIN
)
1964 xprt_end_transmit(task
);
1965 dprint_status(task
);
1966 switch (task
->tk_status
) {
1980 * Problem reaching the server. Disconnect and let the
1981 * forechannel reestablish the connection. The server will
1982 * have to retransmit the backchannel request and we'll
1983 * reprocess it. Since these ops are idempotent, there's no
1984 * need to cache our reply at this time.
1986 printk(KERN_NOTICE
"RPC: Could not send backchannel reply "
1987 "error: %d\n", task
->tk_status
);
1988 xprt_conditional_disconnect(req
->rq_xprt
,
1989 req
->rq_connect_cookie
);
1993 * We were unable to reply and will have to drop the
1994 * request. The server should reconnect and retransmit.
1996 WARN_ON_ONCE(task
->tk_status
== -EAGAIN
);
1997 printk(KERN_NOTICE
"RPC: Could not send backchannel reply "
1998 "error: %d\n", task
->tk_status
);
2001 rpc_wake_up_queued_task(&req
->rq_xprt
->pending
, task
);
2003 task
->tk_action
= rpc_exit_task
;
2006 req
->rq_connect_cookie
= req
->rq_xprt
->connect_cookie
;
2008 task
->tk_status
= 0;
2010 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
2013 * 6. Sort out the RPC call status
2016 call_status(struct rpc_task
*task
)
2018 struct rpc_clnt
*clnt
= task
->tk_client
;
2019 struct rpc_rqst
*req
= task
->tk_rqstp
;
2022 if (req
->rq_reply_bytes_recvd
> 0 && !req
->rq_bytes_sent
)
2023 task
->tk_status
= req
->rq_reply_bytes_recvd
;
2025 dprint_status(task
);
2027 status
= task
->tk_status
;
2029 task
->tk_action
= call_decode
;
2033 trace_rpc_call_status(task
);
2034 task
->tk_status
= 0;
2040 if (RPC_IS_SOFTCONN(task
)) {
2041 rpc_exit(task
, status
);
2045 * Delay any retries for 3 seconds, then handle as if it
2048 rpc_delay(task
, 3*HZ
);
2050 task
->tk_action
= call_timeout
;
2051 if (!(task
->tk_flags
& RPC_TASK_NO_RETRANS_TIMEOUT
)
2052 && task
->tk_client
->cl_discrtry
)
2053 xprt_conditional_disconnect(req
->rq_xprt
,
2054 req
->rq_connect_cookie
);
2059 rpc_force_rebind(clnt
);
2061 rpc_delay(task
, 3*HZ
);
2064 task
->tk_action
= call_bind
;
2067 rpc_delay(task
, HZ
>>2);
2069 task
->tk_action
= call_transmit
;
2072 /* shutdown or soft timeout */
2073 rpc_exit(task
, status
);
2076 if (clnt
->cl_chatty
)
2077 printk("%s: RPC call returned error %d\n",
2078 clnt
->cl_program
->name
, -status
);
2079 rpc_exit(task
, status
);
2084 * 6a. Handle RPC timeout
2085 * We do not release the request slot, so we keep using the
2086 * same XID for all retransmits.
2089 call_timeout(struct rpc_task
*task
)
2091 struct rpc_clnt
*clnt
= task
->tk_client
;
2093 if (xprt_adjust_timeout(task
->tk_rqstp
) == 0) {
2094 dprintk("RPC: %5u call_timeout (minor)\n", task
->tk_pid
);
2098 dprintk("RPC: %5u call_timeout (major)\n", task
->tk_pid
);
2099 task
->tk_timeouts
++;
2101 if (RPC_IS_SOFTCONN(task
)) {
2102 rpc_exit(task
, -ETIMEDOUT
);
2105 if (RPC_IS_SOFT(task
)) {
2106 if (clnt
->cl_chatty
) {
2108 printk(KERN_NOTICE
"%s: server %s not responding, timed out\n",
2109 clnt
->cl_program
->name
,
2110 rcu_dereference(clnt
->cl_xprt
)->servername
);
2113 if (task
->tk_flags
& RPC_TASK_TIMEOUT
)
2114 rpc_exit(task
, -ETIMEDOUT
);
2116 rpc_exit(task
, -EIO
);
2120 if (!(task
->tk_flags
& RPC_CALL_MAJORSEEN
)) {
2121 task
->tk_flags
|= RPC_CALL_MAJORSEEN
;
2122 if (clnt
->cl_chatty
) {
2124 printk(KERN_NOTICE
"%s: server %s not responding, still trying\n",
2125 clnt
->cl_program
->name
,
2126 rcu_dereference(clnt
->cl_xprt
)->servername
);
2130 rpc_force_rebind(clnt
);
2132 * Did our request time out due to an RPCSEC_GSS out-of-sequence
2133 * event? RFC2203 requires the server to drop all such requests.
2135 rpcauth_invalcred(task
);
2138 task
->tk_action
= call_bind
;
2139 task
->tk_status
= 0;
2143 * 7. Decode the RPC reply
2146 call_decode(struct rpc_task
*task
)
2148 struct rpc_clnt
*clnt
= task
->tk_client
;
2149 struct rpc_rqst
*req
= task
->tk_rqstp
;
2150 kxdrdproc_t decode
= task
->tk_msg
.rpc_proc
->p_decode
;
2153 dprint_status(task
);
2155 if (task
->tk_flags
& RPC_CALL_MAJORSEEN
) {
2156 if (clnt
->cl_chatty
) {
2158 printk(KERN_NOTICE
"%s: server %s OK\n",
2159 clnt
->cl_program
->name
,
2160 rcu_dereference(clnt
->cl_xprt
)->servername
);
2163 task
->tk_flags
&= ~RPC_CALL_MAJORSEEN
;
2167 * Ensure that we see all writes made by xprt_complete_rqst()
2168 * before it changed req->rq_reply_bytes_recvd.
2171 req
->rq_rcv_buf
.len
= req
->rq_private_buf
.len
;
2173 /* Check that the softirq receive buffer is valid */
2174 WARN_ON(memcmp(&req
->rq_rcv_buf
, &req
->rq_private_buf
,
2175 sizeof(req
->rq_rcv_buf
)) != 0);
2177 if (req
->rq_rcv_buf
.len
< 12) {
2178 if (!RPC_IS_SOFT(task
)) {
2179 task
->tk_action
= call_bind
;
2182 dprintk("RPC: %s: too small RPC reply size (%d bytes)\n",
2183 clnt
->cl_program
->name
, task
->tk_status
);
2184 task
->tk_action
= call_timeout
;
2188 p
= rpc_verify_header(task
);
2190 if (p
== ERR_PTR(-EAGAIN
))
2195 task
->tk_action
= rpc_exit_task
;
2198 task
->tk_status
= rpcauth_unwrap_resp(task
, decode
, req
, p
,
2199 task
->tk_msg
.rpc_resp
);
2201 dprintk("RPC: %5u call_decode result %d\n", task
->tk_pid
,
2205 task
->tk_status
= 0;
2206 /* Note: rpc_verify_header() may have freed the RPC slot */
2207 if (task
->tk_rqstp
== req
) {
2208 req
->rq_reply_bytes_recvd
= req
->rq_rcv_buf
.len
= 0;
2209 if (task
->tk_client
->cl_discrtry
)
2210 xprt_conditional_disconnect(req
->rq_xprt
,
2211 req
->rq_connect_cookie
);
2216 rpc_encode_header(struct rpc_task
*task
)
2218 struct rpc_clnt
*clnt
= task
->tk_client
;
2219 struct rpc_rqst
*req
= task
->tk_rqstp
;
2220 __be32
*p
= req
->rq_svec
[0].iov_base
;
2222 /* FIXME: check buffer size? */
2224 p
= xprt_skip_transport_header(req
->rq_xprt
, p
);
2225 *p
++ = req
->rq_xid
; /* XID */
2226 *p
++ = htonl(RPC_CALL
); /* CALL */
2227 *p
++ = htonl(RPC_VERSION
); /* RPC version */
2228 *p
++ = htonl(clnt
->cl_prog
); /* program number */
2229 *p
++ = htonl(clnt
->cl_vers
); /* program version */
2230 *p
++ = htonl(task
->tk_msg
.rpc_proc
->p_proc
); /* procedure */
2231 p
= rpcauth_marshcred(task
, p
);
2232 req
->rq_slen
= xdr_adjust_iovec(&req
->rq_svec
[0], p
);
2237 rpc_verify_header(struct rpc_task
*task
)
2239 struct rpc_clnt
*clnt
= task
->tk_client
;
2240 struct kvec
*iov
= &task
->tk_rqstp
->rq_rcv_buf
.head
[0];
2241 int len
= task
->tk_rqstp
->rq_rcv_buf
.len
>> 2;
2242 __be32
*p
= iov
->iov_base
;
2244 int error
= -EACCES
;
2246 if ((task
->tk_rqstp
->rq_rcv_buf
.len
& 3) != 0) {
2247 /* RFC-1014 says that the representation of XDR data must be a
2248 * multiple of four bytes
2249 * - if it isn't pointer subtraction in the NFS client may give
2252 dprintk("RPC: %5u %s: XDR representation not a multiple of"
2253 " 4 bytes: 0x%x\n", task
->tk_pid
, __func__
,
2254 task
->tk_rqstp
->rq_rcv_buf
.len
);
2261 p
+= 1; /* skip XID */
2262 if ((n
= ntohl(*p
++)) != RPC_REPLY
) {
2263 dprintk("RPC: %5u %s: not an RPC reply: %x\n",
2264 task
->tk_pid
, __func__
, n
);
2269 if ((n
= ntohl(*p
++)) != RPC_MSG_ACCEPTED
) {
2272 switch ((n
= ntohl(*p
++))) {
2273 case RPC_AUTH_ERROR
:
2276 dprintk("RPC: %5u %s: RPC call version mismatch!\n",
2277 task
->tk_pid
, __func__
);
2278 error
= -EPROTONOSUPPORT
;
2281 dprintk("RPC: %5u %s: RPC call rejected, "
2282 "unknown error: %x\n",
2283 task
->tk_pid
, __func__
, n
);
2289 switch ((n
= ntohl(*p
++))) {
2290 case RPC_AUTH_REJECTEDCRED
:
2291 case RPC_AUTH_REJECTEDVERF
:
2292 case RPCSEC_GSS_CREDPROBLEM
:
2293 case RPCSEC_GSS_CTXPROBLEM
:
2294 if (!task
->tk_cred_retry
)
2296 task
->tk_cred_retry
--;
2297 dprintk("RPC: %5u %s: retry stale creds\n",
2298 task
->tk_pid
, __func__
);
2299 rpcauth_invalcred(task
);
2300 /* Ensure we obtain a new XID! */
2302 task
->tk_action
= call_reserve
;
2304 case RPC_AUTH_BADCRED
:
2305 case RPC_AUTH_BADVERF
:
2306 /* possibly garbled cred/verf? */
2307 if (!task
->tk_garb_retry
)
2309 task
->tk_garb_retry
--;
2310 dprintk("RPC: %5u %s: retry garbled creds\n",
2311 task
->tk_pid
, __func__
);
2312 task
->tk_action
= call_bind
;
2314 case RPC_AUTH_TOOWEAK
:
2316 printk(KERN_NOTICE
"RPC: server %s requires stronger "
2317 "authentication.\n",
2318 rcu_dereference(clnt
->cl_xprt
)->servername
);
2322 dprintk("RPC: %5u %s: unknown auth error: %x\n",
2323 task
->tk_pid
, __func__
, n
);
2326 dprintk("RPC: %5u %s: call rejected %d\n",
2327 task
->tk_pid
, __func__
, n
);
2330 p
= rpcauth_checkverf(task
, p
);
2333 dprintk("RPC: %5u %s: auth check failed with %d\n",
2334 task
->tk_pid
, __func__
, error
);
2335 goto out_garbage
; /* bad verifier, retry */
2337 len
= p
- (__be32
*)iov
->iov_base
- 1;
2340 switch ((n
= ntohl(*p
++))) {
2343 case RPC_PROG_UNAVAIL
:
2344 dprintk_rcu("RPC: %5u %s: program %u is unsupported "
2345 "by server %s\n", task
->tk_pid
, __func__
,
2346 (unsigned int)clnt
->cl_prog
,
2347 rcu_dereference(clnt
->cl_xprt
)->servername
);
2348 error
= -EPFNOSUPPORT
;
2350 case RPC_PROG_MISMATCH
:
2351 dprintk_rcu("RPC: %5u %s: program %u, version %u unsupported "
2352 "by server %s\n", task
->tk_pid
, __func__
,
2353 (unsigned int)clnt
->cl_prog
,
2354 (unsigned int)clnt
->cl_vers
,
2355 rcu_dereference(clnt
->cl_xprt
)->servername
);
2356 error
= -EPROTONOSUPPORT
;
2358 case RPC_PROC_UNAVAIL
:
2359 dprintk_rcu("RPC: %5u %s: proc %s unsupported by program %u, "
2360 "version %u on server %s\n",
2361 task
->tk_pid
, __func__
,
2362 rpc_proc_name(task
),
2363 clnt
->cl_prog
, clnt
->cl_vers
,
2364 rcu_dereference(clnt
->cl_xprt
)->servername
);
2365 error
= -EOPNOTSUPP
;
2367 case RPC_GARBAGE_ARGS
:
2368 dprintk("RPC: %5u %s: server saw garbage\n",
2369 task
->tk_pid
, __func__
);
2372 dprintk("RPC: %5u %s: server accept status: %x\n",
2373 task
->tk_pid
, __func__
, n
);
2378 clnt
->cl_stats
->rpcgarbage
++;
2379 if (task
->tk_garb_retry
) {
2380 task
->tk_garb_retry
--;
2381 dprintk("RPC: %5u %s: retrying\n",
2382 task
->tk_pid
, __func__
);
2383 task
->tk_action
= call_bind
;
2385 return ERR_PTR(-EAGAIN
);
2388 rpc_exit(task
, error
);
2389 dprintk("RPC: %5u %s: call failed with error %d\n", task
->tk_pid
,
2391 return ERR_PTR(error
);
2393 dprintk("RPC: %5u %s: server reply was truncated.\n", task
->tk_pid
,
2398 static void rpcproc_encode_null(void *rqstp
, struct xdr_stream
*xdr
, void *obj
)
2402 static int rpcproc_decode_null(void *rqstp
, struct xdr_stream
*xdr
, void *obj
)
2407 static struct rpc_procinfo rpcproc_null
= {
2408 .p_encode
= rpcproc_encode_null
,
2409 .p_decode
= rpcproc_decode_null
,
2412 static int rpc_ping(struct rpc_clnt
*clnt
)
2414 struct rpc_message msg
= {
2415 .rpc_proc
= &rpcproc_null
,
2418 msg
.rpc_cred
= authnull_ops
.lookup_cred(NULL
, NULL
, 0);
2419 err
= rpc_call_sync(clnt
, &msg
, RPC_TASK_SOFT
| RPC_TASK_SOFTCONN
);
2420 put_rpccred(msg
.rpc_cred
);
2424 struct rpc_task
*rpc_call_null(struct rpc_clnt
*clnt
, struct rpc_cred
*cred
, int flags
)
2426 struct rpc_message msg
= {
2427 .rpc_proc
= &rpcproc_null
,
2430 struct rpc_task_setup task_setup_data
= {
2432 .rpc_message
= &msg
,
2433 .callback_ops
= &rpc_default_ops
,
2436 return rpc_run_task(&task_setup_data
);
2438 EXPORT_SYMBOL_GPL(rpc_call_null
);
2440 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
2441 static void rpc_show_header(void)
2443 printk(KERN_INFO
"-pid- flgs status -client- --rqstp- "
2444 "-timeout ---ops--\n");
2447 static void rpc_show_task(const struct rpc_clnt
*clnt
,
2448 const struct rpc_task
*task
)
2450 const char *rpc_waitq
= "none";
2452 if (RPC_IS_QUEUED(task
))
2453 rpc_waitq
= rpc_qname(task
->tk_waitqueue
);
2455 printk(KERN_INFO
"%5u %04x %6d %8p %8p %8ld %8p %sv%u %s a:%ps q:%s\n",
2456 task
->tk_pid
, task
->tk_flags
, task
->tk_status
,
2457 clnt
, task
->tk_rqstp
, task
->tk_timeout
, task
->tk_ops
,
2458 clnt
->cl_program
->name
, clnt
->cl_vers
, rpc_proc_name(task
),
2459 task
->tk_action
, rpc_waitq
);
2462 void rpc_show_tasks(struct net
*net
)
2464 struct rpc_clnt
*clnt
;
2465 struct rpc_task
*task
;
2467 struct sunrpc_net
*sn
= net_generic(net
, sunrpc_net_id
);
2469 spin_lock(&sn
->rpc_client_lock
);
2470 list_for_each_entry(clnt
, &sn
->all_clients
, cl_clients
) {
2471 spin_lock(&clnt
->cl_lock
);
2472 list_for_each_entry(task
, &clnt
->cl_tasks
, tk_task
) {
2477 rpc_show_task(clnt
, task
);
2479 spin_unlock(&clnt
->cl_lock
);
2481 spin_unlock(&sn
->rpc_client_lock
);
2485 #if IS_ENABLED(CONFIG_SUNRPC_SWAP)
2487 rpc_clnt_swap_activate(struct rpc_clnt
*clnt
)
2490 struct rpc_xprt
*xprt
;
2492 if (atomic_inc_return(&clnt
->cl_swapper
) == 1) {
2495 xprt
= xprt_get(rcu_dereference(clnt
->cl_xprt
));
2499 * If we didn't get a reference, then we likely are
2500 * racing with a migration event. Wait for a grace
2501 * period and try again.
2507 ret
= xprt_enable_swap(xprt
);
2512 EXPORT_SYMBOL_GPL(rpc_clnt_swap_activate
);
2515 rpc_clnt_swap_deactivate(struct rpc_clnt
*clnt
)
2517 struct rpc_xprt
*xprt
;
2519 if (atomic_dec_if_positive(&clnt
->cl_swapper
) == 0) {
2522 xprt
= xprt_get(rcu_dereference(clnt
->cl_xprt
));
2526 * If we didn't get a reference, then we likely are
2527 * racing with a migration event. Wait for a grace
2528 * period and try again.
2534 xprt_disable_swap(xprt
);
2538 EXPORT_SYMBOL_GPL(rpc_clnt_swap_deactivate
);
2539 #endif /* CONFIG_SUNRPC_SWAP */