1/* 2 * linux/net/sunrpc/svc_xprt.c 3 * 4 * Author: Tom Tucker <tom@opengridcomputing.com> 5 */ 6 7#include <linux/sched.h> 8#include <linux/errno.h> 9#include <linux/freezer.h> 10#include <linux/kthread.h> 11#include <linux/slab.h> 12#include <net/sock.h> 13#include <linux/sunrpc/stats.h> 14#include <linux/sunrpc/svc_xprt.h> 15#include <linux/sunrpc/svcsock.h> 16#include <linux/sunrpc/xprt.h> 17#include <linux/module.h> 18 19#define RPCDBG_FACILITY RPCDBG_SVCXPRT 20 21static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt); 22static int svc_deferred_recv(struct svc_rqst *rqstp); 23static struct cache_deferred_req *svc_defer(struct cache_req *req); 24static void svc_age_temp_xprts(unsigned long closure); 25static void svc_delete_xprt(struct svc_xprt *xprt); 26static void svc_xprt_do_enqueue(struct svc_xprt *xprt); 27 28/* apparently the "standard" is that clients close 29 * idle connections after 5 minutes, servers after 30 * 6 minutes 31 * http://www.connectathon.org/talks96/nfstcp.pdf 32 */ 33static int svc_conn_age_period = 6*60; 34 35/* List of registered transport classes */ 36static DEFINE_SPINLOCK(svc_xprt_class_lock); 37static LIST_HEAD(svc_xprt_class_list); 38 39/* SMP locking strategy: 40 * 41 * svc_pool->sp_lock protects most of the fields of that pool. 42 * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt. 43 * when both need to be taken (rare), svc_serv->sv_lock is first. 44 * BKL protects svc_serv->sv_nrthread. 45 * svc_sock->sk_lock protects the svc_sock->sk_deferred list 46 * and the ->sk_info_authunix cache. 47 * 48 * The XPT_BUSY bit in xprt->xpt_flags prevents a transport being 49 * enqueued multiply. During normal transport processing this bit 50 * is set by svc_xprt_enqueue and cleared by svc_xprt_received. 51 * Providers should not manipulate this bit directly. 52 * 53 * Some flags can be set to certain values at any time 54 * providing that certain rules are followed: 55 * 56 * XPT_CONN, XPT_DATA: 57 * - Can be set or cleared at any time. 58 * - After a set, svc_xprt_enqueue must be called to enqueue 59 * the transport for processing. 60 * - After a clear, the transport must be read/accepted. 61 * If this succeeds, it must be set again. 62 * XPT_CLOSE: 63 * - Can set at any time. It is never cleared. 64 * XPT_DEAD: 65 * - Can only be set while XPT_BUSY is held which ensures 66 * that no other thread will be using the transport or will 67 * try to set XPT_DEAD. 68 */ 69 70int svc_reg_xprt_class(struct svc_xprt_class *xcl) 71{ 72 struct svc_xprt_class *cl; 73 int res = -EEXIST; 74 75 dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name); 76 77 INIT_LIST_HEAD(&xcl->xcl_list); 78 spin_lock(&svc_xprt_class_lock); 79 /* Make sure there isn't already a class with the same name */ 80 list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) { 81 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0) 82 goto out; 83 } 84 list_add_tail(&xcl->xcl_list, &svc_xprt_class_list); 85 res = 0; 86out: 87 spin_unlock(&svc_xprt_class_lock); 88 return res; 89} 90EXPORT_SYMBOL_GPL(svc_reg_xprt_class); 91 92void svc_unreg_xprt_class(struct svc_xprt_class *xcl) 93{ 94 dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name); 95 spin_lock(&svc_xprt_class_lock); 96 list_del_init(&xcl->xcl_list); 97 spin_unlock(&svc_xprt_class_lock); 98} 99EXPORT_SYMBOL_GPL(svc_unreg_xprt_class); 100 101/* 102 * Format the transport list for printing 103 */ 104int svc_print_xprts(char *buf, int maxlen) 105{ 106 struct svc_xprt_class *xcl; 107 char tmpstr[80]; 108 int len = 0; 109 buf[0] = '\0'; 110 111 spin_lock(&svc_xprt_class_lock); 112 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) { 113 int slen; 114 115 sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload); 116 slen = strlen(tmpstr); 117 if (len + slen > maxlen) 118 break; 119 len += slen; 120 strcat(buf, tmpstr); 121 } 122 spin_unlock(&svc_xprt_class_lock); 123 124 return len; 125} 126 127static void svc_xprt_free(struct kref *kref) 128{ 129 struct svc_xprt *xprt = 130 container_of(kref, struct svc_xprt, xpt_ref); 131 struct module *owner = xprt->xpt_class->xcl_owner; 132 if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags)) 133 svcauth_unix_info_release(xprt); 134 put_net(xprt->xpt_net); 135 /* See comment on corresponding get in xs_setup_bc_tcp(): */ 136 if (xprt->xpt_bc_xprt) 137 xprt_put(xprt->xpt_bc_xprt); 138 xprt->xpt_ops->xpo_free(xprt); 139 module_put(owner); 140} 141 142void svc_xprt_put(struct svc_xprt *xprt) 143{ 144 kref_put(&xprt->xpt_ref, svc_xprt_free); 145} 146EXPORT_SYMBOL_GPL(svc_xprt_put); 147 148/* 149 * Called by transport drivers to initialize the transport independent 150 * portion of the transport instance. 151 */ 152void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl, 153 struct svc_xprt *xprt, struct svc_serv *serv) 154{ 155 memset(xprt, 0, sizeof(*xprt)); 156 xprt->xpt_class = xcl; 157 xprt->xpt_ops = xcl->xcl_ops; 158 kref_init(&xprt->xpt_ref); 159 xprt->xpt_server = serv; 160 INIT_LIST_HEAD(&xprt->xpt_list); 161 INIT_LIST_HEAD(&xprt->xpt_ready); 162 INIT_LIST_HEAD(&xprt->xpt_deferred); 163 INIT_LIST_HEAD(&xprt->xpt_users); 164 mutex_init(&xprt->xpt_mutex); 165 spin_lock_init(&xprt->xpt_lock); 166 set_bit(XPT_BUSY, &xprt->xpt_flags); 167 rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending"); 168 xprt->xpt_net = get_net(net); 169} 170EXPORT_SYMBOL_GPL(svc_xprt_init); 171 172static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl, 173 struct svc_serv *serv, 174 struct net *net, 175 const int family, 176 const unsigned short port, 177 int flags) 178{ 179 struct sockaddr_in sin = { 180 .sin_family = AF_INET, 181 .sin_addr.s_addr = htonl(INADDR_ANY), 182 .sin_port = htons(port), 183 }; 184#if IS_ENABLED(CONFIG_IPV6) 185 struct sockaddr_in6 sin6 = { 186 .sin6_family = AF_INET6, 187 .sin6_addr = IN6ADDR_ANY_INIT, 188 .sin6_port = htons(port), 189 }; 190#endif 191 struct sockaddr *sap; 192 size_t len; 193 194 switch (family) { 195 case PF_INET: 196 sap = (struct sockaddr *)&sin; 197 len = sizeof(sin); 198 break; 199#if IS_ENABLED(CONFIG_IPV6) 200 case PF_INET6: 201 sap = (struct sockaddr *)&sin6; 202 len = sizeof(sin6); 203 break; 204#endif 205 default: 206 return ERR_PTR(-EAFNOSUPPORT); 207 } 208 209 return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags); 210} 211 212/* 213 * svc_xprt_received conditionally queues the transport for processing 214 * by another thread. The caller must hold the XPT_BUSY bit and must 215 * not thereafter touch transport data. 216 * 217 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or 218 * insufficient) data. 219 */ 220static void svc_xprt_received(struct svc_xprt *xprt) 221{ 222 WARN_ON_ONCE(!test_bit(XPT_BUSY, &xprt->xpt_flags)); 223 if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) 224 return; 225 /* As soon as we clear busy, the xprt could be closed and 226 * 'put', so we need a reference to call svc_xprt_do_enqueue with: 227 */ 228 svc_xprt_get(xprt); 229 smp_mb__before_atomic(); 230 clear_bit(XPT_BUSY, &xprt->xpt_flags); 231 svc_xprt_do_enqueue(xprt); 232 svc_xprt_put(xprt); 233} 234 235void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new) 236{ 237 clear_bit(XPT_TEMP, &new->xpt_flags); 238 spin_lock_bh(&serv->sv_lock); 239 list_add(&new->xpt_list, &serv->sv_permsocks); 240 spin_unlock_bh(&serv->sv_lock); 241 svc_xprt_received(new); 242} 243 244int svc_create_xprt(struct svc_serv *serv, const char *xprt_name, 245 struct net *net, const int family, 246 const unsigned short port, int flags) 247{ 248 struct svc_xprt_class *xcl; 249 250 dprintk("svc: creating transport %s[%d]\n", xprt_name, port); 251 spin_lock(&svc_xprt_class_lock); 252 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) { 253 struct svc_xprt *newxprt; 254 unsigned short newport; 255 256 if (strcmp(xprt_name, xcl->xcl_name)) 257 continue; 258 259 if (!try_module_get(xcl->xcl_owner)) 260 goto err; 261 262 spin_unlock(&svc_xprt_class_lock); 263 newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags); 264 if (IS_ERR(newxprt)) { 265 module_put(xcl->xcl_owner); 266 return PTR_ERR(newxprt); 267 } 268 svc_add_new_perm_xprt(serv, newxprt); 269 newport = svc_xprt_local_port(newxprt); 270 return newport; 271 } 272 err: 273 spin_unlock(&svc_xprt_class_lock); 274 dprintk("svc: transport %s not found\n", xprt_name); 275 276 /* This errno is exposed to user space. Provide a reasonable 277 * perror msg for a bad transport. */ 278 return -EPROTONOSUPPORT; 279} 280EXPORT_SYMBOL_GPL(svc_create_xprt); 281 282/* 283 * Copy the local and remote xprt addresses to the rqstp structure 284 */ 285void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt) 286{ 287 memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen); 288 rqstp->rq_addrlen = xprt->xpt_remotelen; 289 290 /* 291 * Destination address in request is needed for binding the 292 * source address in RPC replies/callbacks later. 293 */ 294 memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen); 295 rqstp->rq_daddrlen = xprt->xpt_locallen; 296} 297EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs); 298 299/** 300 * svc_print_addr - Format rq_addr field for printing 301 * @rqstp: svc_rqst struct containing address to print 302 * @buf: target buffer for formatted address 303 * @len: length of target buffer 304 * 305 */ 306char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len) 307{ 308 return __svc_print_addr(svc_addr(rqstp), buf, len); 309} 310EXPORT_SYMBOL_GPL(svc_print_addr); 311 312/* 313 * Queue up an idle server thread. Must have pool->sp_lock held. 314 * Note: this is really a stack rather than a queue, so that we only 315 * use as many different threads as we need, and the rest don't pollute 316 * the cache. 317 */ 318static void svc_thread_enqueue(struct svc_pool *pool, struct svc_rqst *rqstp) 319{ 320 list_add(&rqstp->rq_list, &pool->sp_threads); 321} 322 323/* 324 * Dequeue an nfsd thread. Must have pool->sp_lock held. 325 */ 326static void svc_thread_dequeue(struct svc_pool *pool, struct svc_rqst *rqstp) 327{ 328 list_del(&rqstp->rq_list); 329} 330 331static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt) 332{ 333 if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE))) 334 return true; 335 if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED))) 336 return xprt->xpt_ops->xpo_has_wspace(xprt); 337 return false; 338} 339 340static void svc_xprt_do_enqueue(struct svc_xprt *xprt) 341{ 342 struct svc_pool *pool; 343 struct svc_rqst *rqstp; 344 int cpu; 345 346 if (!svc_xprt_has_something_to_do(xprt)) 347 return; 348 349 /* Mark transport as busy. It will remain in this state until 350 * the provider calls svc_xprt_received. We update XPT_BUSY 351 * atomically because it also guards against trying to enqueue 352 * the transport twice. 353 */ 354 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) { 355 /* Don't enqueue transport while already enqueued */ 356 dprintk("svc: transport %p busy, not enqueued\n", xprt); 357 return; 358 } 359 360 cpu = get_cpu(); 361 pool = svc_pool_for_cpu(xprt->xpt_server, cpu); 362 spin_lock_bh(&pool->sp_lock); 363 364 pool->sp_stats.packets++; 365 366 if (!list_empty(&pool->sp_threads)) { 367 rqstp = list_entry(pool->sp_threads.next, 368 struct svc_rqst, 369 rq_list); 370 dprintk("svc: transport %p served by daemon %p\n", 371 xprt, rqstp); 372 svc_thread_dequeue(pool, rqstp); 373 if (rqstp->rq_xprt) 374 printk(KERN_ERR 375 "svc_xprt_enqueue: server %p, rq_xprt=%p!\n", 376 rqstp, rqstp->rq_xprt); 377 /* Note the order of the following 3 lines: 378 * We want to assign xprt to rqstp->rq_xprt only _after_ 379 * we've woken up the process, so that we don't race with 380 * the lockless check in svc_get_next_xprt(). 381 */ 382 svc_xprt_get(xprt); 383 wake_up_process(rqstp->rq_task); 384 rqstp->rq_xprt = xprt; 385 pool->sp_stats.threads_woken++; 386 } else { 387 dprintk("svc: transport %p put into queue\n", xprt); 388 list_add_tail(&xprt->xpt_ready, &pool->sp_sockets); 389 pool->sp_stats.sockets_queued++; 390 } 391 392 spin_unlock_bh(&pool->sp_lock); 393 put_cpu(); 394} 395 396/* 397 * Queue up a transport with data pending. If there are idle nfsd 398 * processes, wake 'em up. 399 * 400 */ 401void svc_xprt_enqueue(struct svc_xprt *xprt) 402{ 403 if (test_bit(XPT_BUSY, &xprt->xpt_flags)) 404 return; 405 svc_xprt_do_enqueue(xprt); 406} 407EXPORT_SYMBOL_GPL(svc_xprt_enqueue); 408 409/* 410 * Dequeue the first transport. Must be called with the pool->sp_lock held. 411 */ 412static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool) 413{ 414 struct svc_xprt *xprt; 415 416 if (list_empty(&pool->sp_sockets)) 417 return NULL; 418 419 xprt = list_entry(pool->sp_sockets.next, 420 struct svc_xprt, xpt_ready); 421 list_del_init(&xprt->xpt_ready); 422 423 dprintk("svc: transport %p dequeued, inuse=%d\n", 424 xprt, atomic_read(&xprt->xpt_ref.refcount)); 425 426 return xprt; 427} 428 429/** 430 * svc_reserve - change the space reserved for the reply to a request. 431 * @rqstp: The request in question 432 * @space: new max space to reserve 433 * 434 * Each request reserves some space on the output queue of the transport 435 * to make sure the reply fits. This function reduces that reserved 436 * space to be the amount of space used already, plus @space. 437 * 438 */ 439void svc_reserve(struct svc_rqst *rqstp, int space) 440{ 441 space += rqstp->rq_res.head[0].iov_len; 442 443 if (space < rqstp->rq_reserved) { 444 struct svc_xprt *xprt = rqstp->rq_xprt; 445 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved); 446 rqstp->rq_reserved = space; 447 448 if (xprt->xpt_ops->xpo_adjust_wspace) 449 xprt->xpt_ops->xpo_adjust_wspace(xprt); 450 svc_xprt_enqueue(xprt); 451 } 452} 453EXPORT_SYMBOL_GPL(svc_reserve); 454 455static void svc_xprt_release(struct svc_rqst *rqstp) 456{ 457 struct svc_xprt *xprt = rqstp->rq_xprt; 458 459 rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp); 460 461 kfree(rqstp->rq_deferred); 462 rqstp->rq_deferred = NULL; 463 464 svc_free_res_pages(rqstp); 465 rqstp->rq_res.page_len = 0; 466 rqstp->rq_res.page_base = 0; 467 468 /* Reset response buffer and release 469 * the reservation. 470 * But first, check that enough space was reserved 471 * for the reply, otherwise we have a bug! 472 */ 473 if ((rqstp->rq_res.len) > rqstp->rq_reserved) 474 printk(KERN_ERR "RPC request reserved %d but used %d\n", 475 rqstp->rq_reserved, 476 rqstp->rq_res.len); 477 478 rqstp->rq_res.head[0].iov_len = 0; 479 svc_reserve(rqstp, 0); 480 rqstp->rq_xprt = NULL; 481 482 svc_xprt_put(xprt); 483} 484 485/* 486 * External function to wake up a server waiting for data 487 * This really only makes sense for services like lockd 488 * which have exactly one thread anyway. 489 */ 490void svc_wake_up(struct svc_serv *serv) 491{ 492 struct svc_rqst *rqstp; 493 unsigned int i; 494 struct svc_pool *pool; 495 496 for (i = 0; i < serv->sv_nrpools; i++) { 497 pool = &serv->sv_pools[i]; 498 499 spin_lock_bh(&pool->sp_lock); 500 if (!list_empty(&pool->sp_threads)) { 501 rqstp = list_entry(pool->sp_threads.next, 502 struct svc_rqst, 503 rq_list); 504 dprintk("svc: daemon %p woken up.\n", rqstp); 505 /* 506 svc_thread_dequeue(pool, rqstp); 507 rqstp->rq_xprt = NULL; 508 */ 509 wake_up_process(rqstp->rq_task); 510 } else 511 pool->sp_task_pending = 1; 512 spin_unlock_bh(&pool->sp_lock); 513 } 514} 515EXPORT_SYMBOL_GPL(svc_wake_up); 516 517int svc_port_is_privileged(struct sockaddr *sin) 518{ 519 switch (sin->sa_family) { 520 case AF_INET: 521 return ntohs(((struct sockaddr_in *)sin)->sin_port) 522 < PROT_SOCK; 523 case AF_INET6: 524 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port) 525 < PROT_SOCK; 526 default: 527 return 0; 528 } 529} 530 531/* 532 * Make sure that we don't have too many active connections. If we have, 533 * something must be dropped. It's not clear what will happen if we allow 534 * "too many" connections, but when dealing with network-facing software, 535 * we have to code defensively. Here we do that by imposing hard limits. 536 * 537 * There's no point in trying to do random drop here for DoS 538 * prevention. The NFS clients does 1 reconnect in 15 seconds. An 539 * attacker can easily beat that. 540 * 541 * The only somewhat efficient mechanism would be if drop old 542 * connections from the same IP first. But right now we don't even 543 * record the client IP in svc_sock. 544 * 545 * single-threaded services that expect a lot of clients will probably 546 * need to set sv_maxconn to override the default value which is based 547 * on the number of threads 548 */ 549static void svc_check_conn_limits(struct svc_serv *serv) 550{ 551 unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn : 552 (serv->sv_nrthreads+3) * 20; 553 554 if (serv->sv_tmpcnt > limit) { 555 struct svc_xprt *xprt = NULL; 556 spin_lock_bh(&serv->sv_lock); 557 if (!list_empty(&serv->sv_tempsocks)) { 558 /* Try to help the admin */ 559 net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n", 560 serv->sv_name, serv->sv_maxconn ? 561 "max number of connections" : 562 "number of threads"); 563 /* 564 * Always select the oldest connection. It's not fair, 565 * but so is life 566 */ 567 xprt = list_entry(serv->sv_tempsocks.prev, 568 struct svc_xprt, 569 xpt_list); 570 set_bit(XPT_CLOSE, &xprt->xpt_flags); 571 svc_xprt_get(xprt); 572 } 573 spin_unlock_bh(&serv->sv_lock); 574 575 if (xprt) { 576 svc_xprt_enqueue(xprt); 577 svc_xprt_put(xprt); 578 } 579 } 580} 581 582static int svc_alloc_arg(struct svc_rqst *rqstp) 583{ 584 struct svc_serv *serv = rqstp->rq_server; 585 struct xdr_buf *arg; 586 int pages; 587 int i; 588 589 /* now allocate needed pages. If we get a failure, sleep briefly */ 590 pages = (serv->sv_max_mesg + PAGE_SIZE) / PAGE_SIZE; 591 WARN_ON_ONCE(pages >= RPCSVC_MAXPAGES); 592 if (pages >= RPCSVC_MAXPAGES) 593 /* use as many pages as possible */ 594 pages = RPCSVC_MAXPAGES - 1; 595 for (i = 0; i < pages ; i++) 596 while (rqstp->rq_pages[i] == NULL) { 597 struct page *p = alloc_page(GFP_KERNEL); 598 if (!p) { 599 set_current_state(TASK_INTERRUPTIBLE); 600 if (signalled() || kthread_should_stop()) { 601 set_current_state(TASK_RUNNING); 602 return -EINTR; 603 } 604 schedule_timeout(msecs_to_jiffies(500)); 605 } 606 rqstp->rq_pages[i] = p; 607 } 608 rqstp->rq_page_end = &rqstp->rq_pages[i]; 609 rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */ 610 611 /* Make arg->head point to first page and arg->pages point to rest */ 612 arg = &rqstp->rq_arg; 613 arg->head[0].iov_base = page_address(rqstp->rq_pages[0]); 614 arg->head[0].iov_len = PAGE_SIZE; 615 arg->pages = rqstp->rq_pages + 1; 616 arg->page_base = 0; 617 /* save at least one page for response */ 618 arg->page_len = (pages-2)*PAGE_SIZE; 619 arg->len = (pages-1)*PAGE_SIZE; 620 arg->tail[0].iov_len = 0; 621 return 0; 622} 623 624static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout) 625{ 626 struct svc_xprt *xprt; 627 struct svc_pool *pool = rqstp->rq_pool; 628 long time_left = 0; 629 630 /* Normally we will wait up to 5 seconds for any required 631 * cache information to be provided. 632 */ 633 rqstp->rq_chandle.thread_wait = 5*HZ; 634 635 spin_lock_bh(&pool->sp_lock); 636 xprt = svc_xprt_dequeue(pool); 637 if (xprt) { 638 rqstp->rq_xprt = xprt; 639 svc_xprt_get(xprt); 640 641 /* As there is a shortage of threads and this request 642 * had to be queued, don't allow the thread to wait so 643 * long for cache updates. 644 */ 645 rqstp->rq_chandle.thread_wait = 1*HZ; 646 pool->sp_task_pending = 0; 647 } else { 648 if (pool->sp_task_pending) { 649 pool->sp_task_pending = 0; 650 xprt = ERR_PTR(-EAGAIN); 651 goto out; 652 } 653 /* 654 * We have to be able to interrupt this wait 655 * to bring down the daemons ... 656 */ 657 set_current_state(TASK_INTERRUPTIBLE); 658 659 /* No data pending. Go to sleep */ 660 svc_thread_enqueue(pool, rqstp); 661 spin_unlock_bh(&pool->sp_lock); 662 663 if (!(signalled() || kthread_should_stop())) { 664 time_left = schedule_timeout(timeout); 665 __set_current_state(TASK_RUNNING); 666 667 try_to_freeze(); 668 669 xprt = rqstp->rq_xprt; 670 if (xprt != NULL) 671 return xprt; 672 } else 673 __set_current_state(TASK_RUNNING); 674 675 spin_lock_bh(&pool->sp_lock); 676 if (!time_left) 677 pool->sp_stats.threads_timedout++; 678 679 xprt = rqstp->rq_xprt; 680 if (!xprt) { 681 svc_thread_dequeue(pool, rqstp); 682 spin_unlock_bh(&pool->sp_lock); 683 dprintk("svc: server %p, no data yet\n", rqstp); 684 if (signalled() || kthread_should_stop()) 685 return ERR_PTR(-EINTR); 686 else 687 return ERR_PTR(-EAGAIN); 688 } 689 } 690out: 691 spin_unlock_bh(&pool->sp_lock); 692 return xprt; 693} 694 695static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt) 696{ 697 spin_lock_bh(&serv->sv_lock); 698 set_bit(XPT_TEMP, &newxpt->xpt_flags); 699 list_add(&newxpt->xpt_list, &serv->sv_tempsocks); 700 serv->sv_tmpcnt++; 701 if (serv->sv_temptimer.function == NULL) { 702 /* setup timer to age temp transports */ 703 setup_timer(&serv->sv_temptimer, svc_age_temp_xprts, 704 (unsigned long)serv); 705 mod_timer(&serv->sv_temptimer, 706 jiffies + svc_conn_age_period * HZ); 707 } 708 spin_unlock_bh(&serv->sv_lock); 709 svc_xprt_received(newxpt); 710} 711 712static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt) 713{ 714 struct svc_serv *serv = rqstp->rq_server; 715 int len = 0; 716 717 if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) { 718 dprintk("svc_recv: found XPT_CLOSE\n"); 719 svc_delete_xprt(xprt); 720 /* Leave XPT_BUSY set on the dead xprt: */ 721 return 0; 722 } 723 if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) { 724 struct svc_xprt *newxpt; 725 /* 726 * We know this module_get will succeed because the 727 * listener holds a reference too 728 */ 729 __module_get(xprt->xpt_class->xcl_owner); 730 svc_check_conn_limits(xprt->xpt_server); 731 newxpt = xprt->xpt_ops->xpo_accept(xprt); 732 if (newxpt) 733 svc_add_new_temp_xprt(serv, newxpt); 734 else 735 module_put(xprt->xpt_class->xcl_owner); 736 } else { 737 /* XPT_DATA|XPT_DEFERRED case: */ 738 dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n", 739 rqstp, rqstp->rq_pool->sp_id, xprt, 740 atomic_read(&xprt->xpt_ref.refcount)); 741 rqstp->rq_deferred = svc_deferred_dequeue(xprt); 742 if (rqstp->rq_deferred) 743 len = svc_deferred_recv(rqstp); 744 else 745 len = xprt->xpt_ops->xpo_recvfrom(rqstp); 746 dprintk("svc: got len=%d\n", len); 747 rqstp->rq_reserved = serv->sv_max_mesg; 748 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved); 749 } 750 /* clear XPT_BUSY: */ 751 svc_xprt_received(xprt); 752 return len; 753} 754 755/* 756 * Receive the next request on any transport. This code is carefully 757 * organised not to touch any cachelines in the shared svc_serv 758 * structure, only cachelines in the local svc_pool. 759 */ 760int svc_recv(struct svc_rqst *rqstp, long timeout) 761{ 762 struct svc_xprt *xprt = NULL; 763 struct svc_serv *serv = rqstp->rq_server; 764 int len, err; 765 766 dprintk("svc: server %p waiting for data (to = %ld)\n", 767 rqstp, timeout); 768 769 if (rqstp->rq_xprt) 770 printk(KERN_ERR 771 "svc_recv: service %p, transport not NULL!\n", 772 rqstp); 773 774 err = svc_alloc_arg(rqstp); 775 if (err) 776 return err; 777 778 try_to_freeze(); 779 cond_resched(); 780 if (signalled() || kthread_should_stop()) 781 return -EINTR; 782 783 xprt = svc_get_next_xprt(rqstp, timeout); 784 if (IS_ERR(xprt)) 785 return PTR_ERR(xprt); 786 787 len = svc_handle_xprt(rqstp, xprt); 788 789 /* No data, incomplete (TCP) read, or accept() */ 790 if (len <= 0) 791 goto out; 792 793 clear_bit(XPT_OLD, &xprt->xpt_flags); 794 795 rqstp->rq_secure = xprt->xpt_ops->xpo_secure_port(rqstp); 796 rqstp->rq_chandle.defer = svc_defer; 797 798 if (serv->sv_stats) 799 serv->sv_stats->netcnt++; 800 return len; 801out: 802 rqstp->rq_res.len = 0; 803 svc_xprt_release(rqstp); 804 return -EAGAIN; 805} 806EXPORT_SYMBOL_GPL(svc_recv); 807 808/* 809 * Drop request 810 */ 811void svc_drop(struct svc_rqst *rqstp) 812{ 813 dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt); 814 svc_xprt_release(rqstp); 815} 816EXPORT_SYMBOL_GPL(svc_drop); 817 818/* 819 * Return reply to client. 820 */ 821int svc_send(struct svc_rqst *rqstp) 822{ 823 struct svc_xprt *xprt; 824 int len; 825 struct xdr_buf *xb; 826 827 xprt = rqstp->rq_xprt; 828 if (!xprt) 829 return -EFAULT; 830 831 /* release the receive skb before sending the reply */ 832 rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp); 833 834 /* calculate over-all length */ 835 xb = &rqstp->rq_res; 836 xb->len = xb->head[0].iov_len + 837 xb->page_len + 838 xb->tail[0].iov_len; 839 840 /* Grab mutex to serialize outgoing data. */ 841 mutex_lock(&xprt->xpt_mutex); 842 if (test_bit(XPT_DEAD, &xprt->xpt_flags) 843 || test_bit(XPT_CLOSE, &xprt->xpt_flags)) 844 len = -ENOTCONN; 845 else 846 len = xprt->xpt_ops->xpo_sendto(rqstp); 847 mutex_unlock(&xprt->xpt_mutex); 848 rpc_wake_up(&xprt->xpt_bc_pending); 849 svc_xprt_release(rqstp); 850 851 if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN) 852 return 0; 853 return len; 854} 855 856/* 857 * Timer function to close old temporary transports, using 858 * a mark-and-sweep algorithm. 859 */ 860static void svc_age_temp_xprts(unsigned long closure) 861{ 862 struct svc_serv *serv = (struct svc_serv *)closure; 863 struct svc_xprt *xprt; 864 struct list_head *le, *next; 865 866 dprintk("svc_age_temp_xprts\n"); 867 868 if (!spin_trylock_bh(&serv->sv_lock)) { 869 /* busy, try again 1 sec later */ 870 dprintk("svc_age_temp_xprts: busy\n"); 871 mod_timer(&serv->sv_temptimer, jiffies + HZ); 872 return; 873 } 874 875 list_for_each_safe(le, next, &serv->sv_tempsocks) { 876 xprt = list_entry(le, struct svc_xprt, xpt_list); 877 878 /* First time through, just mark it OLD. Second time 879 * through, close it. */ 880 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags)) 881 continue; 882 if (atomic_read(&xprt->xpt_ref.refcount) > 1 || 883 test_bit(XPT_BUSY, &xprt->xpt_flags)) 884 continue; 885 list_del_init(le); 886 set_bit(XPT_CLOSE, &xprt->xpt_flags); 887 set_bit(XPT_DETACHED, &xprt->xpt_flags); 888 dprintk("queuing xprt %p for closing\n", xprt); 889 890 /* a thread will dequeue and close it soon */ 891 svc_xprt_enqueue(xprt); 892 } 893 spin_unlock_bh(&serv->sv_lock); 894 895 mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ); 896} 897 898static void call_xpt_users(struct svc_xprt *xprt) 899{ 900 struct svc_xpt_user *u; 901 902 spin_lock(&xprt->xpt_lock); 903 while (!list_empty(&xprt->xpt_users)) { 904 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list); 905 list_del(&u->list); 906 u->callback(u); 907 } 908 spin_unlock(&xprt->xpt_lock); 909} 910 911/* 912 * Remove a dead transport 913 */ 914static void svc_delete_xprt(struct svc_xprt *xprt) 915{ 916 struct svc_serv *serv = xprt->xpt_server; 917 struct svc_deferred_req *dr; 918 919 /* Only do this once */ 920 if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags)) 921 BUG(); 922 923 dprintk("svc: svc_delete_xprt(%p)\n", xprt); 924 xprt->xpt_ops->xpo_detach(xprt); 925 926 spin_lock_bh(&serv->sv_lock); 927 if (!test_and_set_bit(XPT_DETACHED, &xprt->xpt_flags)) 928 list_del_init(&xprt->xpt_list); 929 WARN_ON_ONCE(!list_empty(&xprt->xpt_ready)); 930 if (test_bit(XPT_TEMP, &xprt->xpt_flags)) 931 serv->sv_tmpcnt--; 932 spin_unlock_bh(&serv->sv_lock); 933 934 while ((dr = svc_deferred_dequeue(xprt)) != NULL) 935 kfree(dr); 936 937 call_xpt_users(xprt); 938 svc_xprt_put(xprt); 939} 940 941void svc_close_xprt(struct svc_xprt *xprt) 942{ 943 set_bit(XPT_CLOSE, &xprt->xpt_flags); 944 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) 945 /* someone else will have to effect the close */ 946 return; 947 /* 948 * We expect svc_close_xprt() to work even when no threads are 949 * running (e.g., while configuring the server before starting 950 * any threads), so if the transport isn't busy, we delete 951 * it ourself: 952 */ 953 svc_delete_xprt(xprt); 954} 955EXPORT_SYMBOL_GPL(svc_close_xprt); 956 957static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net) 958{ 959 struct svc_xprt *xprt; 960 int ret = 0; 961 962 spin_lock(&serv->sv_lock); 963 list_for_each_entry(xprt, xprt_list, xpt_list) { 964 if (xprt->xpt_net != net) 965 continue; 966 ret++; 967 set_bit(XPT_CLOSE, &xprt->xpt_flags); 968 svc_xprt_enqueue(xprt); 969 } 970 spin_unlock(&serv->sv_lock); 971 return ret; 972} 973 974static struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net) 975{ 976 struct svc_pool *pool; 977 struct svc_xprt *xprt; 978 struct svc_xprt *tmp; 979 int i; 980 981 for (i = 0; i < serv->sv_nrpools; i++) { 982 pool = &serv->sv_pools[i]; 983 984 spin_lock_bh(&pool->sp_lock); 985 list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) { 986 if (xprt->xpt_net != net) 987 continue; 988 list_del_init(&xprt->xpt_ready); 989 spin_unlock_bh(&pool->sp_lock); 990 return xprt; 991 } 992 spin_unlock_bh(&pool->sp_lock); 993 } 994 return NULL; 995} 996 997static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net) 998{ 999 struct svc_xprt *xprt; 1000 1001 while ((xprt = svc_dequeue_net(serv, net))) { 1002 set_bit(XPT_CLOSE, &xprt->xpt_flags); 1003 svc_delete_xprt(xprt); 1004 } 1005} 1006 1007/* 1008 * Server threads may still be running (especially in the case where the 1009 * service is still running in other network namespaces). 1010 * 1011 * So we shut down sockets the same way we would on a running server, by 1012 * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do 1013 * the close. In the case there are no such other threads, 1014 * threads running, svc_clean_up_xprts() does a simple version of a 1015 * server's main event loop, and in the case where there are other 1016 * threads, we may need to wait a little while and then check again to 1017 * see if they're done. 1018 */ 1019void svc_close_net(struct svc_serv *serv, struct net *net) 1020{ 1021 int delay = 0; 1022 1023 while (svc_close_list(serv, &serv->sv_permsocks, net) + 1024 svc_close_list(serv, &serv->sv_tempsocks, net)) { 1025 1026 svc_clean_up_xprts(serv, net); 1027 msleep(delay++); 1028 } 1029} 1030 1031/* 1032 * Handle defer and revisit of requests 1033 */ 1034 1035static void svc_revisit(struct cache_deferred_req *dreq, int too_many) 1036{ 1037 struct svc_deferred_req *dr = 1038 container_of(dreq, struct svc_deferred_req, handle); 1039 struct svc_xprt *xprt = dr->xprt; 1040 1041 spin_lock(&xprt->xpt_lock); 1042 set_bit(XPT_DEFERRED, &xprt->xpt_flags); 1043 if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) { 1044 spin_unlock(&xprt->xpt_lock); 1045 dprintk("revisit canceled\n"); 1046 svc_xprt_put(xprt); 1047 kfree(dr); 1048 return; 1049 } 1050 dprintk("revisit queued\n"); 1051 dr->xprt = NULL; 1052 list_add(&dr->handle.recent, &xprt->xpt_deferred); 1053 spin_unlock(&xprt->xpt_lock); 1054 svc_xprt_enqueue(xprt); 1055 svc_xprt_put(xprt); 1056} 1057 1058/* 1059 * Save the request off for later processing. The request buffer looks 1060 * like this: 1061 * 1062 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail> 1063 * 1064 * This code can only handle requests that consist of an xprt-header 1065 * and rpc-header. 1066 */ 1067static struct cache_deferred_req *svc_defer(struct cache_req *req) 1068{ 1069 struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle); 1070 struct svc_deferred_req *dr; 1071 1072 if (rqstp->rq_arg.page_len || !rqstp->rq_usedeferral) 1073 return NULL; /* if more than a page, give up FIXME */ 1074 if (rqstp->rq_deferred) { 1075 dr = rqstp->rq_deferred; 1076 rqstp->rq_deferred = NULL; 1077 } else { 1078 size_t skip; 1079 size_t size; 1080 /* FIXME maybe discard if size too large */ 1081 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len; 1082 dr = kmalloc(size, GFP_KERNEL); 1083 if (dr == NULL) 1084 return NULL; 1085 1086 dr->handle.owner = rqstp->rq_server; 1087 dr->prot = rqstp->rq_prot; 1088 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen); 1089 dr->addrlen = rqstp->rq_addrlen; 1090 dr->daddr = rqstp->rq_daddr; 1091 dr->argslen = rqstp->rq_arg.len >> 2; 1092 dr->xprt_hlen = rqstp->rq_xprt_hlen; 1093 1094 /* back up head to the start of the buffer and copy */ 1095 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len; 1096 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip, 1097 dr->argslen << 2); 1098 } 1099 svc_xprt_get(rqstp->rq_xprt); 1100 dr->xprt = rqstp->rq_xprt; 1101 rqstp->rq_dropme = true; 1102 1103 dr->handle.revisit = svc_revisit; 1104 return &dr->handle; 1105} 1106 1107/* 1108 * recv data from a deferred request into an active one 1109 */ 1110static int svc_deferred_recv(struct svc_rqst *rqstp) 1111{ 1112 struct svc_deferred_req *dr = rqstp->rq_deferred; 1113 1114 /* setup iov_base past transport header */ 1115 rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2); 1116 /* The iov_len does not include the transport header bytes */ 1117 rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen; 1118 rqstp->rq_arg.page_len = 0; 1119 /* The rq_arg.len includes the transport header bytes */ 1120 rqstp->rq_arg.len = dr->argslen<<2; 1121 rqstp->rq_prot = dr->prot; 1122 memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen); 1123 rqstp->rq_addrlen = dr->addrlen; 1124 /* Save off transport header len in case we get deferred again */ 1125 rqstp->rq_xprt_hlen = dr->xprt_hlen; 1126 rqstp->rq_daddr = dr->daddr; 1127 rqstp->rq_respages = rqstp->rq_pages; 1128 return (dr->argslen<<2) - dr->xprt_hlen; 1129} 1130 1131 1132static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt) 1133{ 1134 struct svc_deferred_req *dr = NULL; 1135 1136 if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags)) 1137 return NULL; 1138 spin_lock(&xprt->xpt_lock); 1139 if (!list_empty(&xprt->xpt_deferred)) { 1140 dr = list_entry(xprt->xpt_deferred.next, 1141 struct svc_deferred_req, 1142 handle.recent); 1143 list_del_init(&dr->handle.recent); 1144 } else 1145 clear_bit(XPT_DEFERRED, &xprt->xpt_flags); 1146 spin_unlock(&xprt->xpt_lock); 1147 return dr; 1148} 1149 1150/** 1151 * svc_find_xprt - find an RPC transport instance 1152 * @serv: pointer to svc_serv to search 1153 * @xcl_name: C string containing transport's class name 1154 * @net: owner net pointer 1155 * @af: Address family of transport's local address 1156 * @port: transport's IP port number 1157 * 1158 * Return the transport instance pointer for the endpoint accepting 1159 * connections/peer traffic from the specified transport class, 1160 * address family and port. 1161 * 1162 * Specifying 0 for the address family or port is effectively a 1163 * wild-card, and will result in matching the first transport in the 1164 * service's list that has a matching class name. 1165 */ 1166struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name, 1167 struct net *net, const sa_family_t af, 1168 const unsigned short port) 1169{ 1170 struct svc_xprt *xprt; 1171 struct svc_xprt *found = NULL; 1172 1173 /* Sanity check the args */ 1174 if (serv == NULL || xcl_name == NULL) 1175 return found; 1176 1177 spin_lock_bh(&serv->sv_lock); 1178 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) { 1179 if (xprt->xpt_net != net) 1180 continue; 1181 if (strcmp(xprt->xpt_class->xcl_name, xcl_name)) 1182 continue; 1183 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family) 1184 continue; 1185 if (port != 0 && port != svc_xprt_local_port(xprt)) 1186 continue; 1187 found = xprt; 1188 svc_xprt_get(xprt); 1189 break; 1190 } 1191 spin_unlock_bh(&serv->sv_lock); 1192 return found; 1193} 1194EXPORT_SYMBOL_GPL(svc_find_xprt); 1195 1196static int svc_one_xprt_name(const struct svc_xprt *xprt, 1197 char *pos, int remaining) 1198{ 1199 int len; 1200 1201 len = snprintf(pos, remaining, "%s %u\n", 1202 xprt->xpt_class->xcl_name, 1203 svc_xprt_local_port(xprt)); 1204 if (len >= remaining) 1205 return -ENAMETOOLONG; 1206 return len; 1207} 1208 1209/** 1210 * svc_xprt_names - format a buffer with a list of transport names 1211 * @serv: pointer to an RPC service 1212 * @buf: pointer to a buffer to be filled in 1213 * @buflen: length of buffer to be filled in 1214 * 1215 * Fills in @buf with a string containing a list of transport names, 1216 * each name terminated with '\n'. 1217 * 1218 * Returns positive length of the filled-in string on success; otherwise 1219 * a negative errno value is returned if an error occurs. 1220 */ 1221int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen) 1222{ 1223 struct svc_xprt *xprt; 1224 int len, totlen; 1225 char *pos; 1226 1227 /* Sanity check args */ 1228 if (!serv) 1229 return 0; 1230 1231 spin_lock_bh(&serv->sv_lock); 1232 1233 pos = buf; 1234 totlen = 0; 1235 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) { 1236 len = svc_one_xprt_name(xprt, pos, buflen - totlen); 1237 if (len < 0) { 1238 *buf = '\0'; 1239 totlen = len; 1240 } 1241 if (len <= 0) 1242 break; 1243 1244 pos += len; 1245 totlen += len; 1246 } 1247 1248 spin_unlock_bh(&serv->sv_lock); 1249 return totlen; 1250} 1251EXPORT_SYMBOL_GPL(svc_xprt_names); 1252 1253 1254/*----------------------------------------------------------------------------*/ 1255 1256static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos) 1257{ 1258 unsigned int pidx = (unsigned int)*pos; 1259 struct svc_serv *serv = m->private; 1260 1261 dprintk("svc_pool_stats_start, *pidx=%u\n", pidx); 1262 1263 if (!pidx) 1264 return SEQ_START_TOKEN; 1265 return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]); 1266} 1267 1268static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos) 1269{ 1270 struct svc_pool *pool = p; 1271 struct svc_serv *serv = m->private; 1272 1273 dprintk("svc_pool_stats_next, *pos=%llu\n", *pos); 1274 1275 if (p == SEQ_START_TOKEN) { 1276 pool = &serv->sv_pools[0]; 1277 } else { 1278 unsigned int pidx = (pool - &serv->sv_pools[0]); 1279 if (pidx < serv->sv_nrpools-1) 1280 pool = &serv->sv_pools[pidx+1]; 1281 else 1282 pool = NULL; 1283 } 1284 ++*pos; 1285 return pool; 1286} 1287 1288static void svc_pool_stats_stop(struct seq_file *m, void *p) 1289{ 1290} 1291 1292static int svc_pool_stats_show(struct seq_file *m, void *p) 1293{ 1294 struct svc_pool *pool = p; 1295 1296 if (p == SEQ_START_TOKEN) { 1297 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n"); 1298 return 0; 1299 } 1300 1301 seq_printf(m, "%u %lu %lu %lu %lu\n", 1302 pool->sp_id, 1303 pool->sp_stats.packets, 1304 pool->sp_stats.sockets_queued, 1305 pool->sp_stats.threads_woken, 1306 pool->sp_stats.threads_timedout); 1307 1308 return 0; 1309} 1310 1311static const struct seq_operations svc_pool_stats_seq_ops = { 1312 .start = svc_pool_stats_start, 1313 .next = svc_pool_stats_next, 1314 .stop = svc_pool_stats_stop, 1315 .show = svc_pool_stats_show, 1316}; 1317 1318int svc_pool_stats_open(struct svc_serv *serv, struct file *file) 1319{ 1320 int err; 1321 1322 err = seq_open(file, &svc_pool_stats_seq_ops); 1323 if (!err) 1324 ((struct seq_file *) file->private_data)->private = serv; 1325 return err; 1326} 1327EXPORT_SYMBOL(svc_pool_stats_open); 1328 1329/*----------------------------------------------------------------------------*/ 1330