1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * linux/include/linux/sunrpc/svc.h
4  *
5  * RPC server declarations.
6  *
7  * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
8  */
9 
10 
11 #ifndef SUNRPC_SVC_H
12 #define SUNRPC_SVC_H
13 
14 #include <linux/in.h>
15 #include <linux/in6.h>
16 #include <linux/sunrpc/types.h>
17 #include <linux/sunrpc/xdr.h>
18 #include <linux/sunrpc/auth.h>
19 #include <linux/sunrpc/svcauth.h>
20 #include <linux/wait.h>
21 #include <linux/mm.h>
22 #include <linux/pagevec.h>
23 
24 /* statistics for svc_pool structures */
25 struct svc_pool_stats {
26 	atomic_long_t	packets;
27 	unsigned long	sockets_queued;
28 	atomic_long_t	threads_woken;
29 	atomic_long_t	threads_timedout;
30 };
31 
32 /*
33  *
34  * RPC service thread pool.
35  *
36  * Pool of threads and temporary sockets.  Generally there is only
37  * a single one of these per RPC service, but on NUMA machines those
38  * services that can benefit from it (i.e. nfs but not lockd) will
39  * have one pool per NUMA node.  This optimisation reduces cross-
40  * node traffic on multi-node NUMA NFS servers.
41  */
42 struct svc_pool {
43 	unsigned int		sp_id;	    	/* pool id; also node id on NUMA */
44 	spinlock_t		sp_lock;	/* protects all fields */
45 	struct list_head	sp_sockets;	/* pending sockets */
46 	unsigned int		sp_nrthreads;	/* # of threads in pool */
47 	struct list_head	sp_all_threads;	/* all server threads */
48 	struct svc_pool_stats	sp_stats;	/* statistics on pool operation */
49 #define	SP_TASK_PENDING		(0)		/* still work to do even if no
50 						 * xprt is queued. */
51 #define SP_CONGESTED		(1)
52 	unsigned long		sp_flags;
53 } ____cacheline_aligned_in_smp;
54 
55 struct svc_serv;
56 
57 struct svc_serv_ops {
58 	/* Callback to use when last thread exits. */
59 	void		(*svo_shutdown)(struct svc_serv *, struct net *);
60 
61 	/* function for service threads to run */
62 	int		(*svo_function)(void *);
63 
64 	/* queue up a transport for servicing */
65 	void		(*svo_enqueue_xprt)(struct svc_xprt *);
66 
67 	/* set up thread (or whatever) execution context */
68 	int		(*svo_setup)(struct svc_serv *, struct svc_pool *, int);
69 
70 	/* optional module to count when adding threads (pooled svcs only) */
71 	struct module	*svo_module;
72 };
73 
74 /*
75  * RPC service.
76  *
77  * An RPC service is a ``daemon,'' possibly multithreaded, which
78  * receives and processes incoming RPC messages.
79  * It has one or more transport sockets associated with it, and maintains
80  * a list of idle threads waiting for input.
81  *
82  * We currently do not support more than one RPC program per daemon.
83  */
84 struct svc_serv {
85 	struct svc_program *	sv_program;	/* RPC program */
86 	struct svc_stat *	sv_stats;	/* RPC statistics */
87 	spinlock_t		sv_lock;
88 	unsigned int		sv_nrthreads;	/* # of server threads */
89 	unsigned int		sv_maxconn;	/* max connections allowed or
90 						 * '0' causing max to be based
91 						 * on number of threads. */
92 
93 	unsigned int		sv_max_payload;	/* datagram payload size */
94 	unsigned int		sv_max_mesg;	/* max_payload + 1 page for overheads */
95 	unsigned int		sv_xdrsize;	/* XDR buffer size */
96 	struct list_head	sv_permsocks;	/* all permanent sockets */
97 	struct list_head	sv_tempsocks;	/* all temporary sockets */
98 	int			sv_tmpcnt;	/* count of temporary sockets */
99 	struct timer_list	sv_temptimer;	/* timer for aging temporary sockets */
100 
101 	char *			sv_name;	/* service name */
102 
103 	unsigned int		sv_nrpools;	/* number of thread pools */
104 	struct svc_pool *	sv_pools;	/* array of thread pools */
105 	const struct svc_serv_ops *sv_ops;	/* server operations */
106 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
107 	struct list_head	sv_cb_list;	/* queue for callback requests
108 						 * that arrive over the same
109 						 * connection */
110 	spinlock_t		sv_cb_lock;	/* protects the svc_cb_list */
111 	wait_queue_head_t	sv_cb_waitq;	/* sleep here if there are no
112 						 * entries in the svc_cb_list */
113 	bool			sv_bc_enabled;	/* service uses backchannel */
114 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
115 };
116 
117 /*
118  * We use sv_nrthreads as a reference count.  svc_destroy() drops
119  * this refcount, so we need to bump it up around operations that
120  * change the number of threads.  Horrible, but there it is.
121  * Should be called with the "service mutex" held.
122  */
svc_get(struct svc_serv * serv)123 static inline void svc_get(struct svc_serv *serv)
124 {
125 	serv->sv_nrthreads++;
126 }
127 
128 /*
129  * Maximum payload size supported by a kernel RPC server.
130  * This is use to determine the max number of pages nfsd is
131  * willing to return in a single READ operation.
132  *
133  * These happen to all be powers of 2, which is not strictly
134  * necessary but helps enforce the real limitation, which is
135  * that they should be multiples of PAGE_SIZE.
136  *
137  * For UDP transports, a block plus NFS,RPC, and UDP headers
138  * has to fit into the IP datagram limit of 64K.  The largest
139  * feasible number for all known page sizes is probably 48K,
140  * but we choose 32K here.  This is the same as the historical
141  * Linux limit; someone who cares more about NFS/UDP performance
142  * can test a larger number.
143  *
144  * For TCP transports we have more freedom.  A size of 1MB is
145  * chosen to match the client limit.  Other OSes are known to
146  * have larger limits, but those numbers are probably beyond
147  * the point of diminishing returns.
148  */
149 #define RPCSVC_MAXPAYLOAD	(1*1024*1024u)
150 #define RPCSVC_MAXPAYLOAD_TCP	RPCSVC_MAXPAYLOAD
151 #define RPCSVC_MAXPAYLOAD_UDP	(32*1024u)
152 
153 extern u32 svc_max_payload(const struct svc_rqst *rqstp);
154 
155 /*
156  * RPC Requsts and replies are stored in one or more pages.
157  * We maintain an array of pages for each server thread.
158  * Requests are copied into these pages as they arrive.  Remaining
159  * pages are available to write the reply into.
160  *
161  * Pages are sent using ->sendpage so each server thread needs to
162  * allocate more to replace those used in sending.  To help keep track
163  * of these pages we have a receive list where all pages initialy live,
164  * and a send list where pages are moved to when there are to be part
165  * of a reply.
166  *
167  * We use xdr_buf for holding responses as it fits well with NFS
168  * read responses (that have a header, and some data pages, and possibly
169  * a tail) and means we can share some client side routines.
170  *
171  * The xdr_buf.head kvec always points to the first page in the rq_*pages
172  * list.  The xdr_buf.pages pointer points to the second page on that
173  * list.  xdr_buf.tail points to the end of the first page.
174  * This assumes that the non-page part of an rpc reply will fit
175  * in a page - NFSd ensures this.  lockd also has no trouble.
176  *
177  * Each request/reply pair can have at most one "payload", plus two pages,
178  * one for the request, and one for the reply.
179  * We using ->sendfile to return read data, we might need one extra page
180  * if the request is not page-aligned.  So add another '1'.
181  */
182 #define RPCSVC_MAXPAGES		((RPCSVC_MAXPAYLOAD+PAGE_SIZE-1)/PAGE_SIZE \
183 				+ 2 + 1)
184 
svc_getnl(struct kvec * iov)185 static inline u32 svc_getnl(struct kvec *iov)
186 {
187 	__be32 val, *vp;
188 	vp = iov->iov_base;
189 	val = *vp++;
190 	iov->iov_base = (void*)vp;
191 	iov->iov_len -= sizeof(__be32);
192 	return ntohl(val);
193 }
194 
svc_putnl(struct kvec * iov,u32 val)195 static inline void svc_putnl(struct kvec *iov, u32 val)
196 {
197 	__be32 *vp = iov->iov_base + iov->iov_len;
198 	*vp = htonl(val);
199 	iov->iov_len += sizeof(__be32);
200 }
201 
svc_getu32(struct kvec * iov)202 static inline __be32 svc_getu32(struct kvec *iov)
203 {
204 	__be32 val, *vp;
205 	vp = iov->iov_base;
206 	val = *vp++;
207 	iov->iov_base = (void*)vp;
208 	iov->iov_len -= sizeof(__be32);
209 	return val;
210 }
211 
svc_ungetu32(struct kvec * iov)212 static inline void svc_ungetu32(struct kvec *iov)
213 {
214 	__be32 *vp = (__be32 *)iov->iov_base;
215 	iov->iov_base = (void *)(vp - 1);
216 	iov->iov_len += sizeof(*vp);
217 }
218 
svc_putu32(struct kvec * iov,__be32 val)219 static inline void svc_putu32(struct kvec *iov, __be32 val)
220 {
221 	__be32 *vp = iov->iov_base + iov->iov_len;
222 	*vp = val;
223 	iov->iov_len += sizeof(__be32);
224 }
225 
226 /*
227  * The context of a single thread, including the request currently being
228  * processed.
229  */
230 struct svc_rqst {
231 	struct list_head	rq_all;		/* all threads list */
232 	struct rcu_head		rq_rcu_head;	/* for RCU deferred kfree */
233 	struct svc_xprt *	rq_xprt;	/* transport ptr */
234 
235 	struct sockaddr_storage	rq_addr;	/* peer address */
236 	size_t			rq_addrlen;
237 	struct sockaddr_storage	rq_daddr;	/* dest addr of request
238 						 *  - reply from here */
239 	size_t			rq_daddrlen;
240 
241 	struct svc_serv *	rq_server;	/* RPC service definition */
242 	struct svc_pool *	rq_pool;	/* thread pool */
243 	const struct svc_procedure *rq_procinfo;/* procedure info */
244 	struct auth_ops *	rq_authop;	/* authentication flavour */
245 	struct svc_cred		rq_cred;	/* auth info */
246 	void *			rq_xprt_ctxt;	/* transport specific context ptr */
247 	struct svc_deferred_req*rq_deferred;	/* deferred request we are replaying */
248 
249 	size_t			rq_xprt_hlen;	/* xprt header len */
250 	struct xdr_buf		rq_arg;
251 	struct xdr_stream	rq_arg_stream;
252 	struct xdr_stream	rq_res_stream;
253 	struct page		*rq_scratch_page;
254 	struct xdr_buf		rq_res;
255 	struct page		*rq_pages[RPCSVC_MAXPAGES + 1];
256 	struct page *		*rq_respages;	/* points into rq_pages */
257 	struct page *		*rq_next_page; /* next reply page to use */
258 	struct page *		*rq_page_end;  /* one past the last page */
259 
260 	struct pagevec		rq_pvec;
261 	struct kvec		rq_vec[RPCSVC_MAXPAGES]; /* generally useful.. */
262 	struct bio_vec		rq_bvec[RPCSVC_MAXPAGES];
263 
264 	__be32			rq_xid;		/* transmission id */
265 	u32			rq_prog;	/* program number */
266 	u32			rq_vers;	/* program version */
267 	u32			rq_proc;	/* procedure number */
268 	u32			rq_prot;	/* IP protocol */
269 	int			rq_cachetype;	/* catering to nfsd */
270 #define	RQ_SECURE	(0)			/* secure port */
271 #define	RQ_LOCAL	(1)			/* local request */
272 #define	RQ_USEDEFERRAL	(2)			/* use deferral */
273 #define	RQ_DROPME	(3)			/* drop current reply */
274 #define	RQ_SPLICE_OK	(4)			/* turned off in gss privacy
275 						 * to prevent encrypting page
276 						 * cache pages */
277 #define	RQ_VICTIM	(5)			/* about to be shut down */
278 #define	RQ_BUSY		(6)			/* request is busy */
279 #define	RQ_DATA		(7)			/* request has data */
280 	unsigned long		rq_flags;	/* flags field */
281 	ktime_t			rq_qtime;	/* enqueue time */
282 
283 	void *			rq_argp;	/* decoded arguments */
284 	void *			rq_resp;	/* xdr'd results */
285 	void *			rq_auth_data;	/* flavor-specific data */
286 	__be32			rq_auth_stat;	/* authentication status */
287 	int			rq_auth_slack;	/* extra space xdr code
288 						 * should leave in head
289 						 * for krb5i, krb5p.
290 						 */
291 	int			rq_reserved;	/* space on socket outq
292 						 * reserved for this request
293 						 */
294 	ktime_t			rq_stime;	/* start time */
295 
296 	struct cache_req	rq_chandle;	/* handle passed to caches for
297 						 * request delaying
298 						 */
299 	/* Catering to nfsd */
300 	struct auth_domain *	rq_client;	/* RPC peer info */
301 	struct auth_domain *	rq_gssclient;	/* "gss/"-style peer info */
302 	struct svc_cacherep *	rq_cacherep;	/* cache info */
303 	struct task_struct	*rq_task;	/* service thread */
304 	spinlock_t		rq_lock;	/* per-request lock */
305 	struct net		*rq_bc_net;	/* pointer to backchannel's
306 						 * net namespace
307 						 */
308 	void **			rq_lease_breaker; /* The v4 client breaking a lease */
309 };
310 
311 #define SVC_NET(rqst) (rqst->rq_xprt ? rqst->rq_xprt->xpt_net : rqst->rq_bc_net)
312 
313 /*
314  * Rigorous type checking on sockaddr type conversions
315  */
svc_addr_in(const struct svc_rqst * rqst)316 static inline struct sockaddr_in *svc_addr_in(const struct svc_rqst *rqst)
317 {
318 	return (struct sockaddr_in *) &rqst->rq_addr;
319 }
320 
svc_addr_in6(const struct svc_rqst * rqst)321 static inline struct sockaddr_in6 *svc_addr_in6(const struct svc_rqst *rqst)
322 {
323 	return (struct sockaddr_in6 *) &rqst->rq_addr;
324 }
325 
svc_addr(const struct svc_rqst * rqst)326 static inline struct sockaddr *svc_addr(const struct svc_rqst *rqst)
327 {
328 	return (struct sockaddr *) &rqst->rq_addr;
329 }
330 
svc_daddr_in(const struct svc_rqst * rqst)331 static inline struct sockaddr_in *svc_daddr_in(const struct svc_rqst *rqst)
332 {
333 	return (struct sockaddr_in *) &rqst->rq_daddr;
334 }
335 
svc_daddr_in6(const struct svc_rqst * rqst)336 static inline struct sockaddr_in6 *svc_daddr_in6(const struct svc_rqst *rqst)
337 {
338 	return (struct sockaddr_in6 *) &rqst->rq_daddr;
339 }
340 
svc_daddr(const struct svc_rqst * rqst)341 static inline struct sockaddr *svc_daddr(const struct svc_rqst *rqst)
342 {
343 	return (struct sockaddr *) &rqst->rq_daddr;
344 }
345 
346 /*
347  * Check buffer bounds after decoding arguments
348  */
349 static inline int
xdr_argsize_check(struct svc_rqst * rqstp,__be32 * p)350 xdr_argsize_check(struct svc_rqst *rqstp, __be32 *p)
351 {
352 	char *cp = (char *)p;
353 	struct kvec *vec = &rqstp->rq_arg.head[0];
354 	return cp >= (char*)vec->iov_base
355 		&& cp <= (char*)vec->iov_base + vec->iov_len;
356 }
357 
358 static inline int
xdr_ressize_check(struct svc_rqst * rqstp,__be32 * p)359 xdr_ressize_check(struct svc_rqst *rqstp, __be32 *p)
360 {
361 	struct kvec *vec = &rqstp->rq_res.head[0];
362 	char *cp = (char*)p;
363 
364 	vec->iov_len = cp - (char*)vec->iov_base;
365 
366 	return vec->iov_len <= PAGE_SIZE;
367 }
368 
svc_free_res_pages(struct svc_rqst * rqstp)369 static inline void svc_free_res_pages(struct svc_rqst *rqstp)
370 {
371 	while (rqstp->rq_next_page != rqstp->rq_respages) {
372 		struct page **pp = --rqstp->rq_next_page;
373 		if (*pp) {
374 			put_page(*pp);
375 			*pp = NULL;
376 		}
377 	}
378 }
379 
380 struct svc_deferred_req {
381 	u32			prot;	/* protocol (UDP or TCP) */
382 	struct svc_xprt		*xprt;
383 	struct sockaddr_storage	addr;	/* where reply must go */
384 	size_t			addrlen;
385 	struct sockaddr_storage	daddr;	/* where reply must come from */
386 	size_t			daddrlen;
387 	struct cache_deferred_req handle;
388 	size_t			xprt_hlen;
389 	int			argslen;
390 	__be32			args[];
391 };
392 
393 struct svc_process_info {
394 	union {
395 		int  (*dispatch)(struct svc_rqst *, __be32 *);
396 		struct {
397 			unsigned int lovers;
398 			unsigned int hivers;
399 		} mismatch;
400 	};
401 };
402 
403 /*
404  * List of RPC programs on the same transport endpoint
405  */
406 struct svc_program {
407 	struct svc_program *	pg_next;	/* other programs (same xprt) */
408 	u32			pg_prog;	/* program number */
409 	unsigned int		pg_lovers;	/* lowest version */
410 	unsigned int		pg_hivers;	/* highest version */
411 	unsigned int		pg_nvers;	/* number of versions */
412 	const struct svc_version **pg_vers;	/* version array */
413 	char *			pg_name;	/* service name */
414 	char *			pg_class;	/* class name: services sharing authentication */
415 	struct svc_stat *	pg_stats;	/* rpc statistics */
416 	int			(*pg_authenticate)(struct svc_rqst *);
417 	__be32			(*pg_init_request)(struct svc_rqst *,
418 						   const struct svc_program *,
419 						   struct svc_process_info *);
420 	int			(*pg_rpcbind_set)(struct net *net,
421 						  const struct svc_program *,
422 						  u32 version, int family,
423 						  unsigned short proto,
424 						  unsigned short port);
425 };
426 
427 /*
428  * RPC program version
429  */
430 struct svc_version {
431 	u32			vs_vers;	/* version number */
432 	u32			vs_nproc;	/* number of procedures */
433 	const struct svc_procedure *vs_proc;	/* per-procedure info */
434 	unsigned int		*vs_count;	/* call counts */
435 	u32			vs_xdrsize;	/* xdrsize needed for this version */
436 
437 	/* Don't register with rpcbind */
438 	bool			vs_hidden;
439 
440 	/* Don't care if the rpcbind registration fails */
441 	bool			vs_rpcb_optnl;
442 
443 	/* Need xprt with congestion control */
444 	bool			vs_need_cong_ctrl;
445 
446 	/* Override dispatch function (e.g. when caching replies).
447 	 * A return value of 0 means drop the request.
448 	 * vs_dispatch == NULL means use default dispatcher.
449 	 */
450 	int			(*vs_dispatch)(struct svc_rqst *, __be32 *);
451 };
452 
453 /*
454  * RPC procedure info
455  */
456 struct svc_procedure {
457 	/* process the request: */
458 	__be32			(*pc_func)(struct svc_rqst *);
459 	/* XDR decode args: */
460 	int			(*pc_decode)(struct svc_rqst *, __be32 *data);
461 	/* XDR encode result: */
462 	int			(*pc_encode)(struct svc_rqst *, __be32 *data);
463 	/* XDR free result: */
464 	void			(*pc_release)(struct svc_rqst *);
465 	unsigned int		pc_argsize;	/* argument struct size */
466 	unsigned int		pc_ressize;	/* result struct size */
467 	unsigned int		pc_cachetype;	/* cache info (NFS) */
468 	unsigned int		pc_xdrressize;	/* maximum size of XDR reply */
469 	const char *		pc_name;	/* for display */
470 };
471 
472 /*
473  * Mode for mapping cpus to pools.
474  */
475 enum {
476 	SVC_POOL_AUTO = -1,	/* choose one of the others */
477 	SVC_POOL_GLOBAL,	/* no mapping, just a single global pool
478 				 * (legacy & UP mode) */
479 	SVC_POOL_PERCPU,	/* one pool per cpu */
480 	SVC_POOL_PERNODE	/* one pool per numa node */
481 };
482 
483 struct svc_pool_map {
484 	int count;			/* How many svc_servs use us */
485 	int mode;			/* Note: int not enum to avoid
486 					 * warnings about "enumeration value
487 					 * not handled in switch" */
488 	unsigned int npools;
489 	unsigned int *pool_to;		/* maps pool id to cpu or node */
490 	unsigned int *to_pool;		/* maps cpu or node to pool id */
491 };
492 
493 extern struct svc_pool_map svc_pool_map;
494 
495 /*
496  * Function prototypes.
497  */
498 int svc_rpcb_setup(struct svc_serv *serv, struct net *net);
499 void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net);
500 int svc_bind(struct svc_serv *serv, struct net *net);
501 struct svc_serv *svc_create(struct svc_program *, unsigned int,
502 			    const struct svc_serv_ops *);
503 struct svc_rqst *svc_rqst_alloc(struct svc_serv *serv,
504 					struct svc_pool *pool, int node);
505 struct svc_rqst *svc_prepare_thread(struct svc_serv *serv,
506 					struct svc_pool *pool, int node);
507 void		   svc_rqst_replace_page(struct svc_rqst *rqstp,
508 					 struct page *page);
509 void		   svc_rqst_free(struct svc_rqst *);
510 void		   svc_exit_thread(struct svc_rqst *);
511 unsigned int	   svc_pool_map_get(void);
512 void		   svc_pool_map_put(void);
513 struct svc_serv *  svc_create_pooled(struct svc_program *, unsigned int,
514 			const struct svc_serv_ops *);
515 int		   svc_set_num_threads(struct svc_serv *, struct svc_pool *, int);
516 int		   svc_set_num_threads_sync(struct svc_serv *, struct svc_pool *, int);
517 int		   svc_pool_stats_open(struct svc_serv *serv, struct file *file);
518 void		   svc_destroy(struct svc_serv *);
519 void		   svc_shutdown_net(struct svc_serv *, struct net *);
520 int		   svc_process(struct svc_rqst *);
521 int		   bc_svc_process(struct svc_serv *, struct rpc_rqst *,
522 			struct svc_rqst *);
523 int		   svc_register(const struct svc_serv *, struct net *, const int,
524 				const unsigned short, const unsigned short);
525 
526 void		   svc_wake_up(struct svc_serv *);
527 void		   svc_reserve(struct svc_rqst *rqstp, int space);
528 struct svc_pool *  svc_pool_for_cpu(struct svc_serv *serv, int cpu);
529 char *		   svc_print_addr(struct svc_rqst *, char *, size_t);
530 const char *	   svc_proc_name(const struct svc_rqst *rqstp);
531 int		   svc_encode_result_payload(struct svc_rqst *rqstp,
532 					     unsigned int offset,
533 					     unsigned int length);
534 unsigned int	   svc_fill_write_vector(struct svc_rqst *rqstp,
535 					 struct page **pages,
536 					 struct kvec *first, size_t total);
537 char		  *svc_fill_symlink_pathname(struct svc_rqst *rqstp,
538 					     struct kvec *first, void *p,
539 					     size_t total);
540 __be32		   svc_generic_init_request(struct svc_rqst *rqstp,
541 					    const struct svc_program *progp,
542 					    struct svc_process_info *procinfo);
543 int		   svc_generic_rpcbind_set(struct net *net,
544 					   const struct svc_program *progp,
545 					   u32 version, int family,
546 					   unsigned short proto,
547 					   unsigned short port);
548 int		   svc_rpcbind_set_version(struct net *net,
549 					   const struct svc_program *progp,
550 					   u32 version, int family,
551 					   unsigned short proto,
552 					   unsigned short port);
553 
554 #define	RPC_MAX_ADDRBUFLEN	(63U)
555 
556 /*
557  * When we want to reduce the size of the reserved space in the response
558  * buffer, we need to take into account the size of any checksum data that
559  * may be at the end of the packet. This is difficult to determine exactly
560  * for all cases without actually generating the checksum, so we just use a
561  * static value.
562  */
svc_reserve_auth(struct svc_rqst * rqstp,int space)563 static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space)
564 {
565 	svc_reserve(rqstp, space + rqstp->rq_auth_slack);
566 }
567 
568 /**
569  * svcxdr_init_decode - Prepare an xdr_stream for svc Call decoding
570  * @rqstp: controlling server RPC transaction context
571  *
572  */
svcxdr_init_decode(struct svc_rqst * rqstp)573 static inline void svcxdr_init_decode(struct svc_rqst *rqstp)
574 {
575 	struct xdr_stream *xdr = &rqstp->rq_arg_stream;
576 	struct kvec *argv = rqstp->rq_arg.head;
577 
578 	xdr_init_decode(xdr, &rqstp->rq_arg, argv->iov_base, NULL);
579 	xdr_set_scratch_page(xdr, rqstp->rq_scratch_page);
580 }
581 
582 /**
583  * svcxdr_init_encode - Prepare an xdr_stream for svc Reply encoding
584  * @rqstp: controlling server RPC transaction context
585  *
586  */
svcxdr_init_encode(struct svc_rqst * rqstp)587 static inline void svcxdr_init_encode(struct svc_rqst *rqstp)
588 {
589 	struct xdr_stream *xdr = &rqstp->rq_res_stream;
590 	struct xdr_buf *buf = &rqstp->rq_res;
591 	struct kvec *resv = buf->head;
592 
593 	xdr_reset_scratch_buffer(xdr);
594 
595 	xdr->buf = buf;
596 	xdr->iov = resv;
597 	xdr->p   = resv->iov_base + resv->iov_len;
598 	xdr->end = resv->iov_base + PAGE_SIZE - rqstp->rq_auth_slack;
599 	buf->len = resv->iov_len;
600 	xdr->page_ptr = buf->pages - 1;
601 	buf->buflen = PAGE_SIZE * (1 + rqstp->rq_page_end - buf->pages);
602 	buf->buflen -= rqstp->rq_auth_slack;
603 	xdr->rqst = NULL;
604 }
605 
606 #endif /* SUNRPC_SVC_H */
607