xref: /linux/include/linux/sunrpc/xprt.h (revision 79790b6818e96c58fe2bffee1b418c16e64e7b80)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  *  linux/include/linux/sunrpc/xprt.h
4  *
5  *  Declarations for the RPC transport interface.
6  *
7  *  Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
8  */
9 
10 #ifndef _LINUX_SUNRPC_XPRT_H
11 #define _LINUX_SUNRPC_XPRT_H
12 
13 #include <linux/uio.h>
14 #include <linux/socket.h>
15 #include <linux/in.h>
16 #include <linux/ktime.h>
17 #include <linux/kref.h>
18 #include <linux/sunrpc/sched.h>
19 #include <linux/sunrpc/xdr.h>
20 #include <linux/sunrpc/msg_prot.h>
21 
22 #define RPC_MIN_SLOT_TABLE	(2U)
23 #define RPC_DEF_SLOT_TABLE	(16U)
24 #define RPC_MAX_SLOT_TABLE_LIMIT	(65536U)
25 #define RPC_MAX_SLOT_TABLE	RPC_MAX_SLOT_TABLE_LIMIT
26 
27 #define RPC_CWNDSHIFT		(8U)
28 #define RPC_CWNDSCALE		(1U << RPC_CWNDSHIFT)
29 #define RPC_INITCWND		RPC_CWNDSCALE
30 #define RPC_MAXCWND(xprt)	((xprt)->max_reqs << RPC_CWNDSHIFT)
31 #define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
32 
33 enum rpc_display_format_t {
34 	RPC_DISPLAY_ADDR = 0,
35 	RPC_DISPLAY_PORT,
36 	RPC_DISPLAY_PROTO,
37 	RPC_DISPLAY_HEX_ADDR,
38 	RPC_DISPLAY_HEX_PORT,
39 	RPC_DISPLAY_NETID,
40 	RPC_DISPLAY_MAX,
41 };
42 
43 struct rpc_task;
44 struct rpc_xprt;
45 struct xprt_class;
46 struct seq_file;
47 struct svc_serv;
48 struct net;
49 #include <linux/lwq.h>
50 
51 /*
52  * This describes a complete RPC request
53  */
54 struct rpc_rqst {
55 	/*
56 	 * This is the user-visible part
57 	 */
58 	struct rpc_xprt *	rq_xprt;		/* RPC client */
59 	struct xdr_buf		rq_snd_buf;		/* send buffer */
60 	struct xdr_buf		rq_rcv_buf;		/* recv buffer */
61 
62 	/*
63 	 * This is the private part
64 	 */
65 	struct rpc_task *	rq_task;	/* RPC task data */
66 	struct rpc_cred *	rq_cred;	/* Bound cred */
67 	__be32			rq_xid;		/* request XID */
68 	int			rq_cong;	/* has incremented xprt->cong */
69 	u32			rq_seqno;	/* gss seq no. used on req. */
70 	int			rq_enc_pages_num;
71 	struct page		**rq_enc_pages;	/* scratch pages for use by
72 						   gss privacy code */
73 	void (*rq_release_snd_buf)(struct rpc_rqst *); /* release rq_enc_pages */
74 
75 	union {
76 		struct list_head	rq_list;	/* Slot allocation list */
77 		struct rb_node		rq_recv;	/* Receive queue */
78 	};
79 
80 	struct list_head	rq_xmit;	/* Send queue */
81 	struct list_head	rq_xmit2;	/* Send queue */
82 
83 	void			*rq_buffer;	/* Call XDR encode buffer */
84 	size_t			rq_callsize;
85 	void			*rq_rbuffer;	/* Reply XDR decode buffer */
86 	size_t			rq_rcvsize;
87 	size_t			rq_xmit_bytes_sent;	/* total bytes sent */
88 	size_t			rq_reply_bytes_recvd;	/* total reply bytes */
89 							/* received */
90 
91 	struct xdr_buf		rq_private_buf;		/* The receive buffer
92 							 * used in the softirq.
93 							 */
94 	unsigned long		rq_majortimeo;	/* major timeout alarm */
95 	unsigned long		rq_minortimeo;	/* minor timeout alarm */
96 	unsigned long		rq_timeout;	/* Current timeout value */
97 	ktime_t			rq_rtt;		/* round-trip time */
98 	unsigned int		rq_retries;	/* # of retries */
99 	unsigned int		rq_connect_cookie;
100 						/* A cookie used to track the
101 						   state of the transport
102 						   connection */
103 	atomic_t		rq_pin;
104 
105 	/*
106 	 * Partial send handling
107 	 */
108 	u32			rq_bytes_sent;	/* Bytes we have sent */
109 
110 	ktime_t			rq_xtime;	/* transmit time stamp */
111 	int			rq_ntrans;
112 
113 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
114 	struct lwq_node		rq_bc_list;	/* Callback service list */
115 	unsigned long		rq_bc_pa_state;	/* Backchannel prealloc state */
116 	struct list_head	rq_bc_pa_list;	/* Backchannel prealloc list */
117 #endif /* CONFIG_SUNRPC_BACKCHANEL */
118 };
119 #define rq_svec			rq_snd_buf.head
120 #define rq_slen			rq_snd_buf.len
121 
122 /* RPC transport layer security policies */
123 enum xprtsec_policies {
124 	RPC_XPRTSEC_NONE = 0,
125 	RPC_XPRTSEC_TLS_ANON,
126 	RPC_XPRTSEC_TLS_X509,
127 };
128 
129 struct xprtsec_parms {
130 	enum xprtsec_policies	policy;
131 
132 	/* authentication material */
133 	key_serial_t		cert_serial;
134 	key_serial_t		privkey_serial;
135 };
136 
137 struct rpc_xprt_ops {
138 	void		(*set_buffer_size)(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize);
139 	int		(*reserve_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
140 	void		(*release_xprt)(struct rpc_xprt *xprt, struct rpc_task *task);
141 	void		(*alloc_slot)(struct rpc_xprt *xprt, struct rpc_task *task);
142 	void		(*free_slot)(struct rpc_xprt *xprt,
143 				     struct rpc_rqst *req);
144 	void		(*rpcbind)(struct rpc_task *task);
145 	void		(*set_port)(struct rpc_xprt *xprt, unsigned short port);
146 	void		(*connect)(struct rpc_xprt *xprt, struct rpc_task *task);
147 	int		(*get_srcaddr)(struct rpc_xprt *xprt, char *buf,
148 				       size_t buflen);
149 	unsigned short	(*get_srcport)(struct rpc_xprt *xprt);
150 	int		(*buf_alloc)(struct rpc_task *task);
151 	void		(*buf_free)(struct rpc_task *task);
152 	int		(*prepare_request)(struct rpc_rqst *req,
153 					   struct xdr_buf *buf);
154 	int		(*send_request)(struct rpc_rqst *req);
155 	void		(*abort_send_request)(struct rpc_rqst *req);
156 	void		(*wait_for_reply_request)(struct rpc_task *task);
157 	void		(*timer)(struct rpc_xprt *xprt, struct rpc_task *task);
158 	void		(*release_request)(struct rpc_task *task);
159 	void		(*close)(struct rpc_xprt *xprt);
160 	void		(*destroy)(struct rpc_xprt *xprt);
161 	void		(*set_connect_timeout)(struct rpc_xprt *xprt,
162 					unsigned long connect_timeout,
163 					unsigned long reconnect_timeout);
164 	void		(*print_stats)(struct rpc_xprt *xprt, struct seq_file *seq);
165 	int		(*enable_swap)(struct rpc_xprt *xprt);
166 	void		(*disable_swap)(struct rpc_xprt *xprt);
167 	void		(*inject_disconnect)(struct rpc_xprt *xprt);
168 	int		(*bc_setup)(struct rpc_xprt *xprt,
169 				    unsigned int min_reqs);
170 	size_t		(*bc_maxpayload)(struct rpc_xprt *xprt);
171 	unsigned int	(*bc_num_slots)(struct rpc_xprt *xprt);
172 	void		(*bc_free_rqst)(struct rpc_rqst *rqst);
173 	void		(*bc_destroy)(struct rpc_xprt *xprt,
174 				      unsigned int max_reqs);
175 };
176 
177 /*
178  * RPC transport identifiers
179  *
180  * To preserve compatibility with the historical use of raw IP protocol
181  * id's for transport selection, UDP and TCP identifiers are specified
182  * with the previous values. No such restriction exists for new transports,
183  * except that they may not collide with these values (17 and 6,
184  * respectively).
185  */
186 #define XPRT_TRANSPORT_BC       (1 << 31)
187 enum xprt_transports {
188 	XPRT_TRANSPORT_UDP	= IPPROTO_UDP,
189 	XPRT_TRANSPORT_TCP	= IPPROTO_TCP,
190 	XPRT_TRANSPORT_BC_TCP	= IPPROTO_TCP | XPRT_TRANSPORT_BC,
191 	XPRT_TRANSPORT_RDMA	= 256,
192 	XPRT_TRANSPORT_BC_RDMA	= XPRT_TRANSPORT_RDMA | XPRT_TRANSPORT_BC,
193 	XPRT_TRANSPORT_LOCAL	= 257,
194 	XPRT_TRANSPORT_TCP_TLS	= 258,
195 };
196 
197 struct rpc_sysfs_xprt;
198 struct rpc_xprt {
199 	struct kref		kref;		/* Reference count */
200 	const struct rpc_xprt_ops *ops;		/* transport methods */
201 	unsigned int		id;		/* transport id */
202 
203 	const struct rpc_timeout *timeout;	/* timeout parms */
204 	struct sockaddr_storage	addr;		/* server address */
205 	size_t			addrlen;	/* size of server address */
206 	int			prot;		/* IP protocol */
207 
208 	unsigned long		cong;		/* current congestion */
209 	unsigned long		cwnd;		/* congestion window */
210 
211 	size_t			max_payload;	/* largest RPC payload size,
212 						   in bytes */
213 
214 	struct rpc_wait_queue	binding;	/* requests waiting on rpcbind */
215 	struct rpc_wait_queue	sending;	/* requests waiting to send */
216 	struct rpc_wait_queue	pending;	/* requests in flight */
217 	struct rpc_wait_queue	backlog;	/* waiting for slot */
218 	struct list_head	free;		/* free slots */
219 	unsigned int		max_reqs;	/* max number of slots */
220 	unsigned int		min_reqs;	/* min number of slots */
221 	unsigned int		num_reqs;	/* total slots */
222 	unsigned long		state;		/* transport state */
223 	unsigned char		resvport   : 1,	/* use a reserved port */
224 				reuseport  : 1; /* reuse port on reconnect */
225 	atomic_t		swapper;	/* we're swapping over this
226 						   transport */
227 	unsigned int		bind_index;	/* bind function index */
228 
229 	/*
230 	 * Multipath
231 	 */
232 	struct list_head	xprt_switch;
233 
234 	/*
235 	 * Connection of transports
236 	 */
237 	unsigned long		bind_timeout,
238 				reestablish_timeout;
239 	struct xprtsec_parms	xprtsec;
240 	unsigned int		connect_cookie;	/* A cookie that gets bumped
241 						   every time the transport
242 						   is reconnected */
243 
244 	/*
245 	 * Disconnection of idle transports
246 	 */
247 	struct work_struct	task_cleanup;
248 	struct timer_list	timer;
249 	unsigned long		last_used,
250 				idle_timeout,
251 				connect_timeout,
252 				max_reconnect_timeout;
253 
254 	/*
255 	 * Send stuff
256 	 */
257 	atomic_long_t		queuelen;
258 	spinlock_t		transport_lock;	/* lock transport info */
259 	spinlock_t		reserve_lock;	/* lock slot table */
260 	spinlock_t		queue_lock;	/* send/receive queue lock */
261 	u32			xid;		/* Next XID value to use */
262 	struct rpc_task *	snd_task;	/* Task blocked in send */
263 
264 	struct list_head	xmit_queue;	/* Send queue */
265 	atomic_long_t		xmit_queuelen;
266 
267 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
268 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
269 	struct svc_serv		*bc_serv;       /* The RPC service which will */
270 						/* process the callback */
271 	unsigned int		bc_alloc_max;
272 	unsigned int		bc_alloc_count;	/* Total number of preallocs */
273 	atomic_t		bc_slot_count;	/* Number of allocated slots */
274 	spinlock_t		bc_pa_lock;	/* Protects the preallocated
275 						 * items */
276 	struct list_head	bc_pa_list;	/* List of preallocated
277 						 * backchannel rpc_rqst's */
278 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
279 
280 	struct rb_root		recv_queue;	/* Receive queue */
281 
282 	struct {
283 		unsigned long		bind_count,	/* total number of binds */
284 					connect_count,	/* total number of connects */
285 					connect_start,	/* connect start timestamp */
286 					connect_time,	/* jiffies waiting for connect */
287 					sends,		/* how many complete requests */
288 					recvs,		/* how many complete requests */
289 					bad_xids,	/* lookup_rqst didn't find XID */
290 					max_slots;	/* max rpc_slots used */
291 
292 		unsigned long long	req_u,		/* average requests on the wire */
293 					bklog_u,	/* backlog queue utilization */
294 					sending_u,	/* send q utilization */
295 					pending_u;	/* pend q utilization */
296 	} stat;
297 
298 	struct net		*xprt_net;
299 	netns_tracker		ns_tracker;
300 	const char		*servername;
301 	const char		*address_strings[RPC_DISPLAY_MAX];
302 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
303 	struct dentry		*debugfs;		/* debugfs directory */
304 #endif
305 	struct rcu_head		rcu;
306 	const struct xprt_class	*xprt_class;
307 	struct rpc_sysfs_xprt	*xprt_sysfs;
308 	bool			main; /*mark if this is the 1st transport */
309 };
310 
311 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
312 /*
313  * Backchannel flags
314  */
315 #define	RPC_BC_PA_IN_USE	0x0001		/* Preallocated backchannel */
316 						/* buffer in use */
317 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
318 
319 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
bc_prealloc(struct rpc_rqst * req)320 static inline int bc_prealloc(struct rpc_rqst *req)
321 {
322 	return test_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state);
323 }
324 #else
bc_prealloc(struct rpc_rqst * req)325 static inline int bc_prealloc(struct rpc_rqst *req)
326 {
327 	return 0;
328 }
329 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
330 
331 #define XPRT_CREATE_INFINITE_SLOTS	(1U)
332 #define XPRT_CREATE_NO_IDLE_TIMEOUT	(1U << 1)
333 
334 struct xprt_create {
335 	int			ident;		/* XPRT_TRANSPORT identifier */
336 	struct net *		net;
337 	struct sockaddr *	srcaddr;	/* optional local address */
338 	struct sockaddr *	dstaddr;	/* remote peer address */
339 	size_t			addrlen;
340 	const char		*servername;
341 	struct svc_xprt		*bc_xprt;	/* NFSv4.1 backchannel */
342 	struct rpc_xprt_switch	*bc_xps;
343 	unsigned int		flags;
344 	struct xprtsec_parms	xprtsec;
345 	unsigned long		connect_timeout;
346 	unsigned long		reconnect_timeout;
347 };
348 
349 struct xprt_class {
350 	struct list_head	list;
351 	int			ident;		/* XPRT_TRANSPORT identifier */
352 	struct rpc_xprt *	(*setup)(struct xprt_create *);
353 	struct module		*owner;
354 	char			name[32];
355 	const char *		netid[];
356 };
357 
358 /*
359  * Generic internal transport functions
360  */
361 struct rpc_xprt		*xprt_create_transport(struct xprt_create *args);
362 void			xprt_connect(struct rpc_task *task);
363 unsigned long		xprt_reconnect_delay(const struct rpc_xprt *xprt);
364 void			xprt_reconnect_backoff(struct rpc_xprt *xprt,
365 					       unsigned long init_to);
366 void			xprt_reserve(struct rpc_task *task);
367 void			xprt_retry_reserve(struct rpc_task *task);
368 int			xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
369 int			xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
370 void			xprt_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task);
371 void			xprt_free_slot(struct rpc_xprt *xprt,
372 				       struct rpc_rqst *req);
373 bool			xprt_prepare_transmit(struct rpc_task *task);
374 void			xprt_request_enqueue_transmit(struct rpc_task *task);
375 int			xprt_request_enqueue_receive(struct rpc_task *task);
376 void			xprt_request_wait_receive(struct rpc_task *task);
377 void			xprt_request_dequeue_xprt(struct rpc_task *task);
378 bool			xprt_request_need_retransmit(struct rpc_task *task);
379 void			xprt_transmit(struct rpc_task *task);
380 void			xprt_end_transmit(struct rpc_task *task);
381 int			xprt_adjust_timeout(struct rpc_rqst *req);
382 void			xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task);
383 void			xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task);
384 void			xprt_release(struct rpc_task *task);
385 struct rpc_xprt *	xprt_get(struct rpc_xprt *xprt);
386 void			xprt_put(struct rpc_xprt *xprt);
387 struct rpc_xprt *	xprt_alloc(struct net *net, size_t size,
388 				unsigned int num_prealloc,
389 				unsigned int max_req);
390 void			xprt_free(struct rpc_xprt *);
391 void			xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task);
392 bool			xprt_wake_up_backlog(struct rpc_xprt *xprt, struct rpc_rqst *req);
393 void			xprt_cleanup_ids(void);
394 
395 static inline int
xprt_enable_swap(struct rpc_xprt * xprt)396 xprt_enable_swap(struct rpc_xprt *xprt)
397 {
398 	return xprt->ops->enable_swap(xprt);
399 }
400 
401 static inline void
xprt_disable_swap(struct rpc_xprt * xprt)402 xprt_disable_swap(struct rpc_xprt *xprt)
403 {
404 	xprt->ops->disable_swap(xprt);
405 }
406 
407 /*
408  * Transport switch helper functions
409  */
410 int			xprt_register_transport(struct xprt_class *type);
411 int			xprt_unregister_transport(struct xprt_class *type);
412 int			xprt_find_transport_ident(const char *);
413 void			xprt_wait_for_reply_request_def(struct rpc_task *task);
414 void			xprt_wait_for_reply_request_rtt(struct rpc_task *task);
415 void			xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
416 void			xprt_wait_for_buffer_space(struct rpc_xprt *xprt);
417 bool			xprt_write_space(struct rpc_xprt *xprt);
418 void			xprt_adjust_cwnd(struct rpc_xprt *xprt, struct rpc_task *task, int result);
419 struct rpc_rqst *	xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid);
420 void			xprt_update_rtt(struct rpc_task *task);
421 void			xprt_complete_rqst(struct rpc_task *task, int copied);
422 void			xprt_pin_rqst(struct rpc_rqst *req);
423 void			xprt_unpin_rqst(struct rpc_rqst *req);
424 void			xprt_release_rqst_cong(struct rpc_task *task);
425 bool			xprt_request_get_cong(struct rpc_xprt *xprt, struct rpc_rqst *req);
426 void			xprt_disconnect_done(struct rpc_xprt *xprt);
427 void			xprt_force_disconnect(struct rpc_xprt *xprt);
428 void			xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie);
429 
430 bool			xprt_lock_connect(struct rpc_xprt *, struct rpc_task *, void *);
431 void			xprt_unlock_connect(struct rpc_xprt *, void *);
432 void			xprt_release_write(struct rpc_xprt *, struct rpc_task *);
433 
434 /*
435  * Reserved bit positions in xprt->state
436  */
437 #define XPRT_LOCKED		(0)
438 #define XPRT_CONNECTED		(1)
439 #define XPRT_CONNECTING		(2)
440 #define XPRT_CLOSE_WAIT		(3)
441 #define XPRT_BOUND		(4)
442 #define XPRT_BINDING		(5)
443 #define XPRT_CLOSING		(6)
444 #define XPRT_OFFLINE		(7)
445 #define XPRT_REMOVE		(8)
446 #define XPRT_CONGESTED		(9)
447 #define XPRT_CWND_WAIT		(10)
448 #define XPRT_WRITE_SPACE	(11)
449 #define XPRT_SND_IS_COOKIE	(12)
450 
xprt_set_connected(struct rpc_xprt * xprt)451 static inline void xprt_set_connected(struct rpc_xprt *xprt)
452 {
453 	set_bit(XPRT_CONNECTED, &xprt->state);
454 }
455 
xprt_clear_connected(struct rpc_xprt * xprt)456 static inline void xprt_clear_connected(struct rpc_xprt *xprt)
457 {
458 	clear_bit(XPRT_CONNECTED, &xprt->state);
459 }
460 
xprt_connected(struct rpc_xprt * xprt)461 static inline int xprt_connected(struct rpc_xprt *xprt)
462 {
463 	return test_bit(XPRT_CONNECTED, &xprt->state);
464 }
465 
xprt_test_and_set_connected(struct rpc_xprt * xprt)466 static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
467 {
468 	return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
469 }
470 
xprt_test_and_clear_connected(struct rpc_xprt * xprt)471 static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
472 {
473 	return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
474 }
475 
xprt_clear_connecting(struct rpc_xprt * xprt)476 static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
477 {
478 	smp_mb__before_atomic();
479 	clear_bit(XPRT_CONNECTING, &xprt->state);
480 	smp_mb__after_atomic();
481 }
482 
xprt_connecting(struct rpc_xprt * xprt)483 static inline int xprt_connecting(struct rpc_xprt *xprt)
484 {
485 	return test_bit(XPRT_CONNECTING, &xprt->state);
486 }
487 
xprt_test_and_set_connecting(struct rpc_xprt * xprt)488 static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
489 {
490 	return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
491 }
492 
xprt_set_bound(struct rpc_xprt * xprt)493 static inline void xprt_set_bound(struct rpc_xprt *xprt)
494 {
495 	test_and_set_bit(XPRT_BOUND, &xprt->state);
496 }
497 
xprt_bound(struct rpc_xprt * xprt)498 static inline int xprt_bound(struct rpc_xprt *xprt)
499 {
500 	return test_bit(XPRT_BOUND, &xprt->state);
501 }
502 
xprt_clear_bound(struct rpc_xprt * xprt)503 static inline void xprt_clear_bound(struct rpc_xprt *xprt)
504 {
505 	clear_bit(XPRT_BOUND, &xprt->state);
506 }
507 
xprt_clear_binding(struct rpc_xprt * xprt)508 static inline void xprt_clear_binding(struct rpc_xprt *xprt)
509 {
510 	smp_mb__before_atomic();
511 	clear_bit(XPRT_BINDING, &xprt->state);
512 	smp_mb__after_atomic();
513 }
514 
xprt_test_and_set_binding(struct rpc_xprt * xprt)515 static inline int xprt_test_and_set_binding(struct rpc_xprt *xprt)
516 {
517 	return test_and_set_bit(XPRT_BINDING, &xprt->state);
518 }
519 
520 void xprt_set_offline_locked(struct rpc_xprt *xprt, struct rpc_xprt_switch *xps);
521 void xprt_set_online_locked(struct rpc_xprt *xprt, struct rpc_xprt_switch *xps);
522 void xprt_delete_locked(struct rpc_xprt *xprt, struct rpc_xprt_switch *xps);
523 #endif /* _LINUX_SUNRPC_XPRT_H */
524