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/lwq.h> 21 #include <linux/wait.h> 22 #include <linux/mm.h> 23 #include <linux/folio_batch.h> 24 #include <linux/kthread.h> 25 26 /* 27 * 28 * RPC service thread pool. 29 * 30 * Pool of threads and temporary sockets. Generally there is only 31 * a single one of these per RPC service, but on NUMA machines those 32 * services that can benefit from it (i.e. nfs but not lockd) will 33 * have one pool per NUMA node. This optimisation reduces cross- 34 * node traffic on multi-node NUMA NFS servers. 35 */ 36 struct svc_pool { 37 unsigned int sp_id; /* pool id; also node id on NUMA */ 38 unsigned int sp_nrthreads; /* # of threads currently running in pool */ 39 unsigned int sp_nrthrmin; /* Min number of threads to run per pool */ 40 unsigned int sp_nrthrmax; /* Max requested number of threads in pool */ 41 struct lwq sp_xprts; /* pending transports */ 42 struct list_head sp_all_threads; /* all server threads */ 43 struct llist_head sp_idle_threads; /* idle server threads */ 44 45 /* statistics on pool operation */ 46 struct percpu_counter sp_messages_arrived; 47 struct percpu_counter sp_sockets_queued; 48 struct percpu_counter sp_threads_woken; 49 50 unsigned long sp_flags; 51 } ____cacheline_aligned_in_smp; 52 53 /* bits for sp_flags */ 54 enum { 55 SP_TASK_PENDING, /* still work to do even if no xprt is queued */ 56 SP_NEED_VICTIM, /* One thread needs to agree to exit */ 57 SP_VICTIM_REMAINS, /* One thread needs to actually exit */ 58 SP_TASK_STARTING, /* Task has started but not added to idle yet */ 59 }; 60 61 62 /* 63 * RPC service. 64 * 65 * An RPC service is a ``daemon,'' possibly multithreaded, which 66 * receives and processes incoming RPC messages. 67 * It has one or more transport sockets associated with it, and maintains 68 * a list of idle threads waiting for input. 69 * 70 * We currently do not support more than one RPC program per daemon. 71 */ 72 struct svc_serv { 73 struct svc_program * sv_programs; /* RPC programs */ 74 struct svc_stat * sv_stats; /* RPC statistics */ 75 spinlock_t sv_lock; 76 unsigned int sv_nprogs; /* Number of sv_programs */ 77 unsigned int sv_nrthreads; /* # of running server threads */ 78 unsigned int sv_max_payload; /* datagram payload size */ 79 unsigned int sv_max_mesg; /* max_payload + 1 page for overheads */ 80 unsigned int sv_xdrsize; /* XDR buffer size */ 81 struct list_head sv_permsocks; /* all permanent sockets */ 82 struct list_head sv_tempsocks; /* all temporary sockets */ 83 int sv_tmpcnt; /* count of temporary "valid" sockets */ 84 struct timer_list sv_temptimer; /* timer for aging temporary sockets */ 85 86 char * sv_name; /* service name */ 87 88 unsigned int sv_nrpools; /* number of thread pools */ 89 bool sv_is_pooled; /* is this a pooled service? */ 90 struct svc_pool * sv_pools; /* array of thread pools */ 91 int (*sv_threadfn)(void *data); 92 93 #if defined(CONFIG_SUNRPC_BACKCHANNEL) 94 struct lwq sv_cb_list; /* queue for callback requests 95 * that arrive over the same 96 * connection */ 97 bool sv_bc_enabled; /* service uses backchannel */ 98 #endif /* CONFIG_SUNRPC_BACKCHANNEL */ 99 }; 100 101 /* This is used by pool_stats to find and lock an svc */ 102 struct svc_info { 103 struct svc_serv *serv; 104 struct mutex *mutex; 105 }; 106 107 void svc_destroy(struct svc_serv **svcp); 108 109 /* 110 * Maximum payload size supported by a kernel RPC server. 111 * This is use to determine the max number of pages nfsd is 112 * willing to return in a single READ operation. 113 * 114 * These happen to all be powers of 2, which is not strictly 115 * necessary but helps enforce the real limitation, which is 116 * that they should be multiples of PAGE_SIZE. 117 * 118 * For UDP transports, a block plus NFS,RPC, and UDP headers 119 * has to fit into the IP datagram limit of 64K. The largest 120 * feasible number for all known page sizes is probably 48K, 121 * but we choose 32K here. This is the same as the historical 122 * Linux limit; someone who cares more about NFS/UDP performance 123 * can test a larger number. 124 * 125 * For non-UDP transports we have more freedom. A size of 4MB is 126 * chosen to accommodate clients that support larger I/O sizes. 127 */ 128 enum { 129 RPCSVC_MAXPAYLOAD = 4 * 1024 * 1024, 130 RPCSVC_MAXPAYLOAD_TCP = RPCSVC_MAXPAYLOAD, 131 RPCSVC_MAXPAYLOAD_UDP = 32 * 1024, 132 }; 133 134 extern u32 svc_max_payload(const struct svc_rqst *rqstp); 135 136 /* 137 * RPC Call and Reply messages each have their own page array. 138 * rq_pages holds the incoming Call message; rq_respages holds 139 * the outgoing Reply message. Both arrays are sized to 140 * svc_serv_maxpages() entries and are allocated dynamically. 141 * 142 * Pages are sent using ->sendmsg with MSG_SPLICE_PAGES so each 143 * server thread needs to allocate more to replace those used in 144 * sending. 145 * 146 * rq_pages request page contract: 147 * 148 * Transport receive paths that move request data pages out of 149 * rq_pages -- TCP multi-fragment reassembly (svc_tcp_save_pages) 150 * and RDMA Read I/O (svc_rdma_clear_rqst_pages) -- NULL those 151 * entries to prevent svc_rqst_release_pages() from freeing pages 152 * still in transport use, and set rq_pages_nfree to the count. 153 * svc_alloc_arg() refills only that many rq_pages entries. 154 * 155 * For rq_respages, svc_rqst_release_pages() NULLs entries in 156 * [rq_respages, rq_next_page) after each RPC. svc_alloc_arg() 157 * refills only that range. 158 * 159 * xdr_buf holds responses; the structure fits NFS read responses 160 * (header, data pages, optional tail) and enables sharing of 161 * client-side routines. 162 * 163 * The xdr_buf.head kvec always points to the first page in the 164 * rq_*pages list. The xdr_buf.pages pointer points to the second 165 * page on that list. xdr_buf.tail points to the end of the first 166 * page. This assumes that the non-page part of an rpc reply will 167 * fit in a page - NFSd ensures this. lockd also has no trouble. 168 */ 169 170 /** 171 * svc_serv_maxpages - maximum count of pages needed for one RPC message 172 * @serv: RPC service context 173 * 174 * Returns a count of pages or vectors that can hold the maximum 175 * size RPC message for @serv. 176 * 177 * Each page array can hold at most one payload plus two 178 * overhead pages (one for the RPC header, one for tail data). 179 * nfsd_splice_actor() might need an extra page when a READ 180 * payload is not page-aligned. 181 */ 182 static inline unsigned long svc_serv_maxpages(const struct svc_serv *serv) 183 { 184 return DIV_ROUND_UP(serv->sv_max_mesg, PAGE_SIZE) + 2 + 1; 185 } 186 187 /* 188 * The context of a single thread, including the request currently being 189 * processed. 190 * 191 * RPC programs are free to use rq_private to stash thread-local information. 192 * The sunrpc layer will not access it. 193 */ 194 struct svc_rqst { 195 struct list_head rq_all; /* all threads list */ 196 struct llist_node rq_idle; /* On the idle list */ 197 struct rcu_head rq_rcu_head; /* for RCU deferred kfree */ 198 struct svc_xprt * rq_xprt; /* transport ptr */ 199 200 struct sockaddr_storage rq_addr; /* peer address */ 201 size_t rq_addrlen; 202 struct sockaddr_storage rq_daddr; /* dest addr of request 203 * - reply from here */ 204 size_t rq_daddrlen; 205 206 struct svc_serv * rq_server; /* RPC service definition */ 207 struct svc_pool * rq_pool; /* thread pool */ 208 const struct svc_procedure *rq_procinfo;/* procedure info */ 209 struct auth_ops * rq_authop; /* authentication flavour */ 210 struct svc_cred rq_cred; /* auth info */ 211 void * rq_xprt_ctxt; /* transport specific context ptr */ 212 struct svc_deferred_req*rq_deferred; /* deferred request we are replaying */ 213 214 struct xdr_buf rq_arg; 215 struct xdr_stream rq_arg_stream; 216 struct xdr_stream rq_res_stream; 217 struct folio *rq_scratch_folio; 218 struct xdr_buf rq_res; 219 unsigned long rq_maxpages; /* entries per page array */ 220 unsigned long rq_pages_nfree; /* rq_pages entries NULLed by transport */ 221 struct page * *rq_pages; /* Call buffer pages */ 222 struct page * *rq_respages; /* Reply buffer pages */ 223 struct page * *rq_next_page; /* next reply page to use */ 224 struct page * *rq_page_end; /* one past the last reply page */ 225 226 struct folio_batch rq_fbatch; 227 struct bio_vec *rq_bvec; 228 229 __be32 rq_xid; /* transmission id */ 230 u32 rq_prog; /* program number */ 231 u32 rq_vers; /* program version */ 232 u32 rq_proc; /* procedure number */ 233 u32 rq_prot; /* IP protocol */ 234 unsigned long rq_flags; /* flags field */ 235 ktime_t rq_qtime; /* enqueue time */ 236 237 void * rq_argp; /* decoded arguments */ 238 void * rq_resp; /* xdr'd results */ 239 __be32 *rq_accept_statp; 240 void * rq_auth_data; /* flavor-specific data */ 241 __be32 rq_auth_stat; /* authentication status */ 242 int rq_auth_slack; /* extra space xdr code 243 * should leave in head 244 * for krb5i, krb5p. 245 */ 246 int rq_reserved; /* space on socket outq 247 * reserved for this request 248 */ 249 ktime_t rq_stime; /* start time */ 250 251 struct cache_req rq_chandle; /* handle passed to caches for 252 * request delaying 253 */ 254 /* Catering to nfsd */ 255 struct auth_domain * rq_client; /* RPC peer info */ 256 struct auth_domain * rq_gssclient; /* "gss/"-style peer info */ 257 struct task_struct *rq_task; /* service thread */ 258 struct net *rq_bc_net; /* pointer to backchannel's 259 * net namespace 260 */ 261 262 int rq_err; /* Thread sets this to inidicate 263 * initialisation success. 264 */ 265 266 unsigned long bc_to_initval; 267 unsigned int bc_to_retries; 268 unsigned int rq_status_counter; /* RPC processing counter */ 269 void *rq_private; /* For use by the service thread */ 270 }; 271 272 /* bits for rq_flags */ 273 enum { 274 RQ_SECURE, /* secure port */ 275 RQ_LOCAL, /* local request */ 276 RQ_USEDEFERRAL, /* use deferral */ 277 RQ_DROPME, /* drop current reply */ 278 RQ_VICTIM, /* Have agreed to shut down */ 279 RQ_DATA, /* request has data */ 280 }; 281 282 #define SVC_NET(rqst) (rqst->rq_xprt ? rqst->rq_xprt->xpt_net : rqst->rq_bc_net) 283 284 /* 285 * Rigorous type checking on sockaddr type conversions 286 */ 287 static inline struct sockaddr_in *svc_addr_in(const struct svc_rqst *rqst) 288 { 289 return (struct sockaddr_in *) &rqst->rq_addr; 290 } 291 292 static inline struct sockaddr_in6 *svc_addr_in6(const struct svc_rqst *rqst) 293 { 294 return (struct sockaddr_in6 *) &rqst->rq_addr; 295 } 296 297 static inline struct sockaddr *svc_addr(const struct svc_rqst *rqst) 298 { 299 return (struct sockaddr *) &rqst->rq_addr; 300 } 301 302 static inline struct sockaddr_in *svc_daddr_in(const struct svc_rqst *rqst) 303 { 304 return (struct sockaddr_in *) &rqst->rq_daddr; 305 } 306 307 static inline struct sockaddr_in6 *svc_daddr_in6(const struct svc_rqst *rqst) 308 { 309 return (struct sockaddr_in6 *) &rqst->rq_daddr; 310 } 311 312 static inline struct sockaddr *svc_daddr(const struct svc_rqst *rqst) 313 { 314 return (struct sockaddr *) &rqst->rq_daddr; 315 } 316 317 /** 318 * svc_thread_should_stop - check if this thread should stop 319 * @rqstp: the thread that might need to stop 320 * 321 * To stop an svc thread, the pool flags SP_NEED_VICTIM and SP_VICTIM_REMAINS 322 * are set. The first thread which sees SP_NEED_VICTIM clears it, becoming 323 * the victim using this function. It should then promptly call 324 * svc_exit_thread() to complete the process, clearing SP_VICTIM_REMAINS 325 * so the task waiting for a thread to exit can wake and continue. 326 * 327 * Return values: 328 * %true: caller should invoke svc_exit_thread() 329 * %false: caller should do nothing 330 */ 331 static inline bool svc_thread_should_stop(struct svc_rqst *rqstp) 332 { 333 if (test_and_clear_bit(SP_NEED_VICTIM, &rqstp->rq_pool->sp_flags)) 334 set_bit(RQ_VICTIM, &rqstp->rq_flags); 335 336 return test_bit(RQ_VICTIM, &rqstp->rq_flags); 337 } 338 339 /** 340 * svc_thread_init_status - report whether thread has initialised successfully 341 * @rqstp: the thread in question 342 * @err: errno code 343 * 344 * After performing any initialisation that could fail, and before starting 345 * normal work, each sunrpc svc_thread must call svc_thread_init_status() 346 * with an appropriate error, or zero. 347 * 348 * If zero is passed, the thread is ready and must continue until 349 * svc_thread_should_stop() returns true. If a non-zero error is passed 350 * the call will not return - the thread will exit. 351 */ 352 static inline void svc_thread_init_status(struct svc_rqst *rqstp, int err) 353 { 354 store_release_wake_up(&rqstp->rq_err, err); 355 if (err) 356 kthread_exit(1); 357 } 358 359 struct svc_deferred_req { 360 u32 prot; /* protocol (UDP or TCP) */ 361 struct svc_xprt *xprt; 362 struct sockaddr_storage addr; /* where reply must go */ 363 size_t addrlen; 364 struct sockaddr_storage daddr; /* where reply must come from */ 365 size_t daddrlen; 366 void *xprt_ctxt; 367 struct cache_deferred_req handle; 368 int argslen; 369 __be32 args[]; 370 }; 371 372 struct svc_process_info { 373 union { 374 int (*dispatch)(struct svc_rqst *rqstp); 375 struct { 376 unsigned int lovers; 377 unsigned int hivers; 378 } mismatch; 379 }; 380 }; 381 382 /* 383 * RPC program - an array of these can use the same transport endpoint 384 */ 385 struct svc_program { 386 u32 pg_prog; /* program number */ 387 unsigned int pg_lovers; /* lowest version */ 388 unsigned int pg_hivers; /* highest version */ 389 unsigned int pg_nvers; /* number of versions */ 390 const struct svc_version **pg_vers; /* version array */ 391 char * pg_name; /* service name */ 392 char * pg_class; /* class name: services sharing authentication */ 393 enum svc_auth_status (*pg_authenticate)(struct svc_rqst *rqstp); 394 __be32 (*pg_init_request)(struct svc_rqst *, 395 const struct svc_program *, 396 struct svc_process_info *); 397 int (*pg_rpcbind_set)(struct net *net, 398 const struct svc_program *, 399 u32 version, int family, 400 unsigned short proto, 401 unsigned short port); 402 }; 403 404 /* 405 * RPC program version 406 */ 407 struct svc_version { 408 u32 vs_vers; /* version number */ 409 u32 vs_nproc; /* number of procedures */ 410 const struct svc_procedure *vs_proc; /* per-procedure info */ 411 unsigned long __percpu *vs_count; /* call counts */ 412 u32 vs_xdrsize; /* xdrsize needed for this version */ 413 414 /* Don't register with rpcbind */ 415 bool vs_hidden; 416 417 /* Don't care if the rpcbind registration fails */ 418 bool vs_rpcb_optnl; 419 420 /* Need xprt with congestion control */ 421 bool vs_need_cong_ctrl; 422 423 /* Dispatch function */ 424 int (*vs_dispatch)(struct svc_rqst *rqstp); 425 }; 426 427 /* 428 * RPC procedure info 429 */ 430 struct svc_procedure { 431 /* process the request: */ 432 __be32 (*pc_func)(struct svc_rqst *); 433 /* XDR decode args: */ 434 bool (*pc_decode)(struct svc_rqst *rqstp, 435 struct xdr_stream *xdr); 436 /* XDR encode result: */ 437 bool (*pc_encode)(struct svc_rqst *rqstp, 438 struct xdr_stream *xdr); 439 /* XDR free result: */ 440 void (*pc_release)(struct svc_rqst *); 441 unsigned int pc_argsize; /* argument struct size */ 442 unsigned int pc_argzero; /* how much of argument to clear */ 443 unsigned int pc_ressize; /* result struct size */ 444 unsigned int pc_cachetype; /* cache info (NFS) */ 445 unsigned int pc_xdrressize; /* maximum size of XDR reply */ 446 const char * pc_name; /* for display */ 447 }; 448 449 /* 450 * Function prototypes. 451 */ 452 int sunrpc_set_pool_mode(const char *val); 453 int sunrpc_get_pool_mode(char *val, size_t size); 454 void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net); 455 int svc_bind(struct svc_serv *serv, struct net *net); 456 struct svc_serv *svc_create(struct svc_program *, unsigned int, 457 int (*threadfn)(void *data)); 458 bool svc_rqst_replace_page(struct svc_rqst *rqstp, 459 struct page *page); 460 void svc_rqst_release_pages(struct svc_rqst *rqstp); 461 int svc_new_thread(struct svc_serv *serv, struct svc_pool *pool); 462 void svc_exit_thread(struct svc_rqst *); 463 struct svc_serv * svc_create_pooled(struct svc_program *prog, 464 unsigned int nprog, 465 struct svc_stat *stats, 466 unsigned int bufsize, 467 int (*threadfn)(void *data)); 468 int svc_set_pool_threads(struct svc_serv *serv, struct svc_pool *pool, 469 unsigned int min_threads, unsigned int max_threads); 470 int svc_set_num_threads(struct svc_serv *serv, unsigned int min_threads, 471 unsigned int nrservs); 472 int svc_pool_stats_open(struct svc_info *si, struct file *file); 473 void svc_process(struct svc_rqst *rqstp); 474 void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp); 475 int svc_register(const struct svc_serv *, struct net *, const int, 476 const unsigned short, const unsigned short); 477 478 void svc_wake_up(struct svc_serv *); 479 void svc_reserve(struct svc_rqst *rqstp, int space); 480 void svc_pool_wake_idle_thread(struct svc_pool *pool); 481 struct svc_pool *svc_pool_for_cpu(struct svc_serv *serv); 482 char * svc_print_addr(struct svc_rqst *, char *, size_t); 483 const char * svc_proc_name(const struct svc_rqst *rqstp); 484 int svc_encode_result_payload(struct svc_rqst *rqstp, 485 unsigned int offset, 486 unsigned int length); 487 char *svc_fill_symlink_pathname(struct svc_rqst *rqstp, 488 struct kvec *first, void *p, 489 size_t total); 490 __be32 svc_generic_init_request(struct svc_rqst *rqstp, 491 const struct svc_program *progp, 492 struct svc_process_info *procinfo); 493 int svc_generic_rpcbind_set(struct net *net, 494 const struct svc_program *progp, 495 u32 version, int family, 496 unsigned short proto, 497 unsigned short port); 498 499 #define RPC_MAX_ADDRBUFLEN (63U) 500 501 /** 502 * svc_rqst_page_release - release a page associated with an RPC transaction 503 * @rqstp: RPC transaction context 504 * @page: page to release 505 * 506 * Released pages are batched and freed together, reducing 507 * allocator pressure under heavy RPC workloads. 508 */ 509 static inline void svc_rqst_page_release(struct svc_rqst *rqstp, 510 struct page *page) 511 { 512 if (!folio_batch_add(&rqstp->rq_fbatch, page_folio(page))) 513 __folio_batch_release(&rqstp->rq_fbatch); 514 } 515 516 /* 517 * When we want to reduce the size of the reserved space in the response 518 * buffer, we need to take into account the size of any checksum data that 519 * may be at the end of the packet. This is difficult to determine exactly 520 * for all cases without actually generating the checksum, so we just use a 521 * static value. 522 */ 523 static inline void svc_reserve_auth(struct svc_rqst *rqstp, int space) 524 { 525 svc_reserve(rqstp, space + rqstp->rq_auth_slack); 526 } 527 528 /** 529 * svcxdr_init_decode - Prepare an xdr_stream for Call decoding 530 * @rqstp: controlling server RPC transaction context 531 * 532 */ 533 static inline void svcxdr_init_decode(struct svc_rqst *rqstp) 534 { 535 struct xdr_stream *xdr = &rqstp->rq_arg_stream; 536 struct xdr_buf *buf = &rqstp->rq_arg; 537 struct kvec *argv = buf->head; 538 539 WARN_ON(buf->len != buf->head->iov_len + buf->page_len + buf->tail->iov_len); 540 buf->len = buf->head->iov_len + buf->page_len + buf->tail->iov_len; 541 542 xdr_init_decode(xdr, buf, argv->iov_base, NULL); 543 xdr_set_scratch_folio(xdr, rqstp->rq_scratch_folio); 544 } 545 546 /** 547 * svcxdr_init_encode - Prepare an xdr_stream for svc Reply encoding 548 * @rqstp: controlling server RPC transaction context 549 * 550 */ 551 static inline void svcxdr_init_encode(struct svc_rqst *rqstp) 552 { 553 struct xdr_stream *xdr = &rqstp->rq_res_stream; 554 struct xdr_buf *buf = &rqstp->rq_res; 555 struct kvec *resv = buf->head; 556 557 xdr_reset_scratch_buffer(xdr); 558 559 xdr->buf = buf; 560 xdr->iov = resv; 561 xdr->p = resv->iov_base + resv->iov_len; 562 xdr->end = resv->iov_base + PAGE_SIZE; 563 buf->len = resv->iov_len; 564 xdr->page_ptr = buf->pages - 1; 565 buf->buflen = PAGE_SIZE * (rqstp->rq_page_end - buf->pages); 566 xdr->rqst = NULL; 567 } 568 569 /** 570 * svcxdr_encode_opaque_pages - Insert pages into an xdr_stream 571 * @xdr: xdr_stream to be updated 572 * @pages: array of pages to insert 573 * @base: starting offset of first data byte in @pages 574 * @len: number of data bytes in @pages to insert 575 * 576 * After the @pages are added, the tail iovec is instantiated pointing 577 * to end of the head buffer, and the stream is set up to encode 578 * subsequent items into the tail. 579 */ 580 static inline void svcxdr_encode_opaque_pages(struct svc_rqst *rqstp, 581 struct xdr_stream *xdr, 582 struct page **pages, 583 unsigned int base, 584 unsigned int len) 585 { 586 xdr_write_pages(xdr, pages, base, len); 587 xdr->page_ptr = rqstp->rq_next_page - 1; 588 } 589 590 /** 591 * svcxdr_set_auth_slack - 592 * @rqstp: RPC transaction 593 * @slack: buffer space to reserve for the transaction's security flavor 594 * 595 * Set the request's slack space requirement, and set aside that much 596 * space in the rqstp's rq_res.head for use when the auth wraps the Reply. 597 */ 598 static inline void svcxdr_set_auth_slack(struct svc_rqst *rqstp, int slack) 599 { 600 struct xdr_stream *xdr = &rqstp->rq_res_stream; 601 struct xdr_buf *buf = &rqstp->rq_res; 602 struct kvec *resv = buf->head; 603 604 rqstp->rq_auth_slack = slack; 605 606 xdr->end -= XDR_QUADLEN(slack); 607 buf->buflen -= rqstp->rq_auth_slack; 608 609 WARN_ON(xdr->iov != resv); 610 WARN_ON(xdr->p > xdr->end); 611 } 612 613 /** 614 * svcxdr_set_accept_stat - Reserve space for the accept_stat field 615 * @rqstp: RPC transaction context 616 * 617 * Return values: 618 * %true: Success 619 * %false: No response buffer space was available 620 */ 621 static inline bool svcxdr_set_accept_stat(struct svc_rqst *rqstp) 622 { 623 struct xdr_stream *xdr = &rqstp->rq_res_stream; 624 625 rqstp->rq_accept_statp = xdr_reserve_space(xdr, XDR_UNIT); 626 if (unlikely(!rqstp->rq_accept_statp)) 627 return false; 628 *rqstp->rq_accept_statp = rpc_success; 629 return true; 630 } 631 632 #endif /* SUNRPC_SVC_H */ 633