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/addr.h> 14 #include <linux/sunrpc/stats.h> 15 #include <linux/sunrpc/svc_xprt.h> 16 #include <linux/sunrpc/svcsock.h> 17 #include <linux/sunrpc/xprt.h> 18 #include <linux/module.h> 19 #include <linux/netdevice.h> 20 #include <trace/events/sunrpc.h> 21 22 #define RPCDBG_FACILITY RPCDBG_SVCXPRT 23 24 static unsigned int svc_rpc_per_connection_limit __read_mostly; 25 module_param(svc_rpc_per_connection_limit, uint, 0644); 26 27 28 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt); 29 static int svc_deferred_recv(struct svc_rqst *rqstp); 30 static struct cache_deferred_req *svc_defer(struct cache_req *req); 31 static void svc_age_temp_xprts(unsigned long closure); 32 static void svc_delete_xprt(struct svc_xprt *xprt); 33 34 /* apparently the "standard" is that clients close 35 * idle connections after 5 minutes, servers after 36 * 6 minutes 37 * http://www.connectathon.org/talks96/nfstcp.pdf 38 */ 39 static int svc_conn_age_period = 6*60; 40 41 /* List of registered transport classes */ 42 static DEFINE_SPINLOCK(svc_xprt_class_lock); 43 static LIST_HEAD(svc_xprt_class_list); 44 45 /* SMP locking strategy: 46 * 47 * svc_pool->sp_lock protects most of the fields of that pool. 48 * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt. 49 * when both need to be taken (rare), svc_serv->sv_lock is first. 50 * The "service mutex" protects svc_serv->sv_nrthread. 51 * svc_sock->sk_lock protects the svc_sock->sk_deferred list 52 * and the ->sk_info_authunix cache. 53 * 54 * The XPT_BUSY bit in xprt->xpt_flags prevents a transport being 55 * enqueued multiply. During normal transport processing this bit 56 * is set by svc_xprt_enqueue and cleared by svc_xprt_received. 57 * Providers should not manipulate this bit directly. 58 * 59 * Some flags can be set to certain values at any time 60 * providing that certain rules are followed: 61 * 62 * XPT_CONN, XPT_DATA: 63 * - Can be set or cleared at any time. 64 * - After a set, svc_xprt_enqueue must be called to enqueue 65 * the transport for processing. 66 * - After a clear, the transport must be read/accepted. 67 * If this succeeds, it must be set again. 68 * XPT_CLOSE: 69 * - Can set at any time. It is never cleared. 70 * XPT_DEAD: 71 * - Can only be set while XPT_BUSY is held which ensures 72 * that no other thread will be using the transport or will 73 * try to set XPT_DEAD. 74 */ 75 int svc_reg_xprt_class(struct svc_xprt_class *xcl) 76 { 77 struct svc_xprt_class *cl; 78 int res = -EEXIST; 79 80 dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name); 81 82 INIT_LIST_HEAD(&xcl->xcl_list); 83 spin_lock(&svc_xprt_class_lock); 84 /* Make sure there isn't already a class with the same name */ 85 list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) { 86 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0) 87 goto out; 88 } 89 list_add_tail(&xcl->xcl_list, &svc_xprt_class_list); 90 res = 0; 91 out: 92 spin_unlock(&svc_xprt_class_lock); 93 return res; 94 } 95 EXPORT_SYMBOL_GPL(svc_reg_xprt_class); 96 97 void svc_unreg_xprt_class(struct svc_xprt_class *xcl) 98 { 99 dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name); 100 spin_lock(&svc_xprt_class_lock); 101 list_del_init(&xcl->xcl_list); 102 spin_unlock(&svc_xprt_class_lock); 103 } 104 EXPORT_SYMBOL_GPL(svc_unreg_xprt_class); 105 106 /* 107 * Format the transport list for printing 108 */ 109 int svc_print_xprts(char *buf, int maxlen) 110 { 111 struct svc_xprt_class *xcl; 112 char tmpstr[80]; 113 int len = 0; 114 buf[0] = '\0'; 115 116 spin_lock(&svc_xprt_class_lock); 117 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) { 118 int slen; 119 120 sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload); 121 slen = strlen(tmpstr); 122 if (len + slen > maxlen) 123 break; 124 len += slen; 125 strcat(buf, tmpstr); 126 } 127 spin_unlock(&svc_xprt_class_lock); 128 129 return len; 130 } 131 132 static void svc_xprt_free(struct kref *kref) 133 { 134 struct svc_xprt *xprt = 135 container_of(kref, struct svc_xprt, xpt_ref); 136 struct module *owner = xprt->xpt_class->xcl_owner; 137 if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags)) 138 svcauth_unix_info_release(xprt); 139 put_net(xprt->xpt_net); 140 /* See comment on corresponding get in xs_setup_bc_tcp(): */ 141 if (xprt->xpt_bc_xprt) 142 xprt_put(xprt->xpt_bc_xprt); 143 if (xprt->xpt_bc_xps) 144 xprt_switch_put(xprt->xpt_bc_xps); 145 xprt->xpt_ops->xpo_free(xprt); 146 module_put(owner); 147 } 148 149 void svc_xprt_put(struct svc_xprt *xprt) 150 { 151 kref_put(&xprt->xpt_ref, svc_xprt_free); 152 } 153 EXPORT_SYMBOL_GPL(svc_xprt_put); 154 155 /* 156 * Called by transport drivers to initialize the transport independent 157 * portion of the transport instance. 158 */ 159 void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl, 160 struct svc_xprt *xprt, struct svc_serv *serv) 161 { 162 memset(xprt, 0, sizeof(*xprt)); 163 xprt->xpt_class = xcl; 164 xprt->xpt_ops = xcl->xcl_ops; 165 kref_init(&xprt->xpt_ref); 166 xprt->xpt_server = serv; 167 INIT_LIST_HEAD(&xprt->xpt_list); 168 INIT_LIST_HEAD(&xprt->xpt_ready); 169 INIT_LIST_HEAD(&xprt->xpt_deferred); 170 INIT_LIST_HEAD(&xprt->xpt_users); 171 mutex_init(&xprt->xpt_mutex); 172 spin_lock_init(&xprt->xpt_lock); 173 set_bit(XPT_BUSY, &xprt->xpt_flags); 174 rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending"); 175 xprt->xpt_net = get_net(net); 176 } 177 EXPORT_SYMBOL_GPL(svc_xprt_init); 178 179 static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl, 180 struct svc_serv *serv, 181 struct net *net, 182 const int family, 183 const unsigned short port, 184 int flags) 185 { 186 struct sockaddr_in sin = { 187 .sin_family = AF_INET, 188 .sin_addr.s_addr = htonl(INADDR_ANY), 189 .sin_port = htons(port), 190 }; 191 #if IS_ENABLED(CONFIG_IPV6) 192 struct sockaddr_in6 sin6 = { 193 .sin6_family = AF_INET6, 194 .sin6_addr = IN6ADDR_ANY_INIT, 195 .sin6_port = htons(port), 196 }; 197 #endif 198 struct sockaddr *sap; 199 size_t len; 200 201 switch (family) { 202 case PF_INET: 203 sap = (struct sockaddr *)&sin; 204 len = sizeof(sin); 205 break; 206 #if IS_ENABLED(CONFIG_IPV6) 207 case PF_INET6: 208 sap = (struct sockaddr *)&sin6; 209 len = sizeof(sin6); 210 break; 211 #endif 212 default: 213 return ERR_PTR(-EAFNOSUPPORT); 214 } 215 216 return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags); 217 } 218 219 /* 220 * svc_xprt_received conditionally queues the transport for processing 221 * by another thread. The caller must hold the XPT_BUSY bit and must 222 * not thereafter touch transport data. 223 * 224 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or 225 * insufficient) data. 226 */ 227 static void svc_xprt_received(struct svc_xprt *xprt) 228 { 229 if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) { 230 WARN_ONCE(1, "xprt=0x%p already busy!", xprt); 231 return; 232 } 233 234 /* As soon as we clear busy, the xprt could be closed and 235 * 'put', so we need a reference to call svc_enqueue_xprt with: 236 */ 237 svc_xprt_get(xprt); 238 smp_mb__before_atomic(); 239 clear_bit(XPT_BUSY, &xprt->xpt_flags); 240 xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt); 241 svc_xprt_put(xprt); 242 } 243 244 void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new) 245 { 246 clear_bit(XPT_TEMP, &new->xpt_flags); 247 spin_lock_bh(&serv->sv_lock); 248 list_add(&new->xpt_list, &serv->sv_permsocks); 249 spin_unlock_bh(&serv->sv_lock); 250 svc_xprt_received(new); 251 } 252 253 int _svc_create_xprt(struct svc_serv *serv, const char *xprt_name, 254 struct net *net, const int family, 255 const unsigned short port, int flags) 256 { 257 struct svc_xprt_class *xcl; 258 259 spin_lock(&svc_xprt_class_lock); 260 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) { 261 struct svc_xprt *newxprt; 262 unsigned short newport; 263 264 if (strcmp(xprt_name, xcl->xcl_name)) 265 continue; 266 267 if (!try_module_get(xcl->xcl_owner)) 268 goto err; 269 270 spin_unlock(&svc_xprt_class_lock); 271 newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags); 272 if (IS_ERR(newxprt)) { 273 module_put(xcl->xcl_owner); 274 return PTR_ERR(newxprt); 275 } 276 svc_add_new_perm_xprt(serv, newxprt); 277 newport = svc_xprt_local_port(newxprt); 278 return newport; 279 } 280 err: 281 spin_unlock(&svc_xprt_class_lock); 282 /* This errno is exposed to user space. Provide a reasonable 283 * perror msg for a bad transport. */ 284 return -EPROTONOSUPPORT; 285 } 286 287 int svc_create_xprt(struct svc_serv *serv, const char *xprt_name, 288 struct net *net, const int family, 289 const unsigned short port, int flags) 290 { 291 int err; 292 293 dprintk("svc: creating transport %s[%d]\n", xprt_name, port); 294 err = _svc_create_xprt(serv, xprt_name, net, family, port, flags); 295 if (err == -EPROTONOSUPPORT) { 296 request_module("svc%s", xprt_name); 297 err = _svc_create_xprt(serv, xprt_name, net, family, port, flags); 298 } 299 if (err) 300 dprintk("svc: transport %s not found, err %d\n", 301 xprt_name, err); 302 return err; 303 } 304 EXPORT_SYMBOL_GPL(svc_create_xprt); 305 306 /* 307 * Copy the local and remote xprt addresses to the rqstp structure 308 */ 309 void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt) 310 { 311 memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen); 312 rqstp->rq_addrlen = xprt->xpt_remotelen; 313 314 /* 315 * Destination address in request is needed for binding the 316 * source address in RPC replies/callbacks later. 317 */ 318 memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen); 319 rqstp->rq_daddrlen = xprt->xpt_locallen; 320 } 321 EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs); 322 323 /** 324 * svc_print_addr - Format rq_addr field for printing 325 * @rqstp: svc_rqst struct containing address to print 326 * @buf: target buffer for formatted address 327 * @len: length of target buffer 328 * 329 */ 330 char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len) 331 { 332 return __svc_print_addr(svc_addr(rqstp), buf, len); 333 } 334 EXPORT_SYMBOL_GPL(svc_print_addr); 335 336 static bool svc_xprt_slots_in_range(struct svc_xprt *xprt) 337 { 338 unsigned int limit = svc_rpc_per_connection_limit; 339 int nrqsts = atomic_read(&xprt->xpt_nr_rqsts); 340 341 return limit == 0 || (nrqsts >= 0 && nrqsts < limit); 342 } 343 344 static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt) 345 { 346 if (!test_bit(RQ_DATA, &rqstp->rq_flags)) { 347 if (!svc_xprt_slots_in_range(xprt)) 348 return false; 349 atomic_inc(&xprt->xpt_nr_rqsts); 350 set_bit(RQ_DATA, &rqstp->rq_flags); 351 } 352 return true; 353 } 354 355 static void svc_xprt_release_slot(struct svc_rqst *rqstp) 356 { 357 struct svc_xprt *xprt = rqstp->rq_xprt; 358 if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) { 359 atomic_dec(&xprt->xpt_nr_rqsts); 360 svc_xprt_enqueue(xprt); 361 } 362 } 363 364 static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt) 365 { 366 if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE))) 367 return true; 368 if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED))) { 369 if (xprt->xpt_ops->xpo_has_wspace(xprt) && 370 svc_xprt_slots_in_range(xprt)) 371 return true; 372 trace_svc_xprt_no_write_space(xprt); 373 return false; 374 } 375 return false; 376 } 377 378 void svc_xprt_do_enqueue(struct svc_xprt *xprt) 379 { 380 struct svc_pool *pool; 381 struct svc_rqst *rqstp = NULL; 382 int cpu; 383 bool queued = false; 384 385 if (!svc_xprt_has_something_to_do(xprt)) 386 goto out; 387 388 /* Mark transport as busy. It will remain in this state until 389 * the provider calls svc_xprt_received. We update XPT_BUSY 390 * atomically because it also guards against trying to enqueue 391 * the transport twice. 392 */ 393 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) { 394 /* Don't enqueue transport while already enqueued */ 395 dprintk("svc: transport %p busy, not enqueued\n", xprt); 396 goto out; 397 } 398 399 cpu = get_cpu(); 400 pool = svc_pool_for_cpu(xprt->xpt_server, cpu); 401 402 atomic_long_inc(&pool->sp_stats.packets); 403 404 redo_search: 405 /* find a thread for this xprt */ 406 rcu_read_lock(); 407 list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) { 408 /* Do a lockless check first */ 409 if (test_bit(RQ_BUSY, &rqstp->rq_flags)) 410 continue; 411 412 /* 413 * Once the xprt has been queued, it can only be dequeued by 414 * the task that intends to service it. All we can do at that 415 * point is to try to wake this thread back up so that it can 416 * do so. 417 */ 418 if (!queued) { 419 spin_lock_bh(&rqstp->rq_lock); 420 if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags)) { 421 /* already busy, move on... */ 422 spin_unlock_bh(&rqstp->rq_lock); 423 continue; 424 } 425 426 /* this one will do */ 427 rqstp->rq_xprt = xprt; 428 svc_xprt_get(xprt); 429 spin_unlock_bh(&rqstp->rq_lock); 430 } 431 rcu_read_unlock(); 432 433 atomic_long_inc(&pool->sp_stats.threads_woken); 434 wake_up_process(rqstp->rq_task); 435 put_cpu(); 436 goto out; 437 } 438 rcu_read_unlock(); 439 440 /* 441 * We didn't find an idle thread to use, so we need to queue the xprt. 442 * Do so and then search again. If we find one, we can't hook this one 443 * up to it directly but we can wake the thread up in the hopes that it 444 * will pick it up once it searches for a xprt to service. 445 */ 446 if (!queued) { 447 queued = true; 448 dprintk("svc: transport %p put into queue\n", xprt); 449 spin_lock_bh(&pool->sp_lock); 450 list_add_tail(&xprt->xpt_ready, &pool->sp_sockets); 451 pool->sp_stats.sockets_queued++; 452 spin_unlock_bh(&pool->sp_lock); 453 goto redo_search; 454 } 455 rqstp = NULL; 456 put_cpu(); 457 out: 458 trace_svc_xprt_do_enqueue(xprt, rqstp); 459 } 460 EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue); 461 462 /* 463 * Queue up a transport with data pending. If there are idle nfsd 464 * processes, wake 'em up. 465 * 466 */ 467 void svc_xprt_enqueue(struct svc_xprt *xprt) 468 { 469 if (test_bit(XPT_BUSY, &xprt->xpt_flags)) 470 return; 471 xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt); 472 } 473 EXPORT_SYMBOL_GPL(svc_xprt_enqueue); 474 475 /* 476 * Dequeue the first transport, if there is one. 477 */ 478 static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool) 479 { 480 struct svc_xprt *xprt = NULL; 481 482 if (list_empty(&pool->sp_sockets)) 483 goto out; 484 485 spin_lock_bh(&pool->sp_lock); 486 if (likely(!list_empty(&pool->sp_sockets))) { 487 xprt = list_first_entry(&pool->sp_sockets, 488 struct svc_xprt, xpt_ready); 489 list_del_init(&xprt->xpt_ready); 490 svc_xprt_get(xprt); 491 492 dprintk("svc: transport %p dequeued, inuse=%d\n", 493 xprt, kref_read(&xprt->xpt_ref)); 494 } 495 spin_unlock_bh(&pool->sp_lock); 496 out: 497 trace_svc_xprt_dequeue(xprt); 498 return xprt; 499 } 500 501 /** 502 * svc_reserve - change the space reserved for the reply to a request. 503 * @rqstp: The request in question 504 * @space: new max space to reserve 505 * 506 * Each request reserves some space on the output queue of the transport 507 * to make sure the reply fits. This function reduces that reserved 508 * space to be the amount of space used already, plus @space. 509 * 510 */ 511 void svc_reserve(struct svc_rqst *rqstp, int space) 512 { 513 space += rqstp->rq_res.head[0].iov_len; 514 515 if (space < rqstp->rq_reserved) { 516 struct svc_xprt *xprt = rqstp->rq_xprt; 517 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved); 518 rqstp->rq_reserved = space; 519 520 svc_xprt_enqueue(xprt); 521 } 522 } 523 EXPORT_SYMBOL_GPL(svc_reserve); 524 525 static void svc_xprt_release(struct svc_rqst *rqstp) 526 { 527 struct svc_xprt *xprt = rqstp->rq_xprt; 528 529 rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp); 530 531 kfree(rqstp->rq_deferred); 532 rqstp->rq_deferred = NULL; 533 534 svc_free_res_pages(rqstp); 535 rqstp->rq_res.page_len = 0; 536 rqstp->rq_res.page_base = 0; 537 538 /* Reset response buffer and release 539 * the reservation. 540 * But first, check that enough space was reserved 541 * for the reply, otherwise we have a bug! 542 */ 543 if ((rqstp->rq_res.len) > rqstp->rq_reserved) 544 printk(KERN_ERR "RPC request reserved %d but used %d\n", 545 rqstp->rq_reserved, 546 rqstp->rq_res.len); 547 548 rqstp->rq_res.head[0].iov_len = 0; 549 svc_reserve(rqstp, 0); 550 svc_xprt_release_slot(rqstp); 551 rqstp->rq_xprt = NULL; 552 svc_xprt_put(xprt); 553 } 554 555 /* 556 * Some svc_serv's will have occasional work to do, even when a xprt is not 557 * waiting to be serviced. This function is there to "kick" a task in one of 558 * those services so that it can wake up and do that work. Note that we only 559 * bother with pool 0 as we don't need to wake up more than one thread for 560 * this purpose. 561 */ 562 void svc_wake_up(struct svc_serv *serv) 563 { 564 struct svc_rqst *rqstp; 565 struct svc_pool *pool; 566 567 pool = &serv->sv_pools[0]; 568 569 rcu_read_lock(); 570 list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) { 571 /* skip any that aren't queued */ 572 if (test_bit(RQ_BUSY, &rqstp->rq_flags)) 573 continue; 574 rcu_read_unlock(); 575 dprintk("svc: daemon %p woken up.\n", rqstp); 576 wake_up_process(rqstp->rq_task); 577 trace_svc_wake_up(rqstp->rq_task->pid); 578 return; 579 } 580 rcu_read_unlock(); 581 582 /* No free entries available */ 583 set_bit(SP_TASK_PENDING, &pool->sp_flags); 584 smp_wmb(); 585 trace_svc_wake_up(0); 586 } 587 EXPORT_SYMBOL_GPL(svc_wake_up); 588 589 int svc_port_is_privileged(struct sockaddr *sin) 590 { 591 switch (sin->sa_family) { 592 case AF_INET: 593 return ntohs(((struct sockaddr_in *)sin)->sin_port) 594 < PROT_SOCK; 595 case AF_INET6: 596 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port) 597 < PROT_SOCK; 598 default: 599 return 0; 600 } 601 } 602 603 /* 604 * Make sure that we don't have too many active connections. If we have, 605 * something must be dropped. It's not clear what will happen if we allow 606 * "too many" connections, but when dealing with network-facing software, 607 * we have to code defensively. Here we do that by imposing hard limits. 608 * 609 * There's no point in trying to do random drop here for DoS 610 * prevention. The NFS clients does 1 reconnect in 15 seconds. An 611 * attacker can easily beat that. 612 * 613 * The only somewhat efficient mechanism would be if drop old 614 * connections from the same IP first. But right now we don't even 615 * record the client IP in svc_sock. 616 * 617 * single-threaded services that expect a lot of clients will probably 618 * need to set sv_maxconn to override the default value which is based 619 * on the number of threads 620 */ 621 static void svc_check_conn_limits(struct svc_serv *serv) 622 { 623 unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn : 624 (serv->sv_nrthreads+3) * 20; 625 626 if (serv->sv_tmpcnt > limit) { 627 struct svc_xprt *xprt = NULL; 628 spin_lock_bh(&serv->sv_lock); 629 if (!list_empty(&serv->sv_tempsocks)) { 630 /* Try to help the admin */ 631 net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n", 632 serv->sv_name, serv->sv_maxconn ? 633 "max number of connections" : 634 "number of threads"); 635 /* 636 * Always select the oldest connection. It's not fair, 637 * but so is life 638 */ 639 xprt = list_entry(serv->sv_tempsocks.prev, 640 struct svc_xprt, 641 xpt_list); 642 set_bit(XPT_CLOSE, &xprt->xpt_flags); 643 svc_xprt_get(xprt); 644 } 645 spin_unlock_bh(&serv->sv_lock); 646 647 if (xprt) { 648 svc_xprt_enqueue(xprt); 649 svc_xprt_put(xprt); 650 } 651 } 652 } 653 654 static int svc_alloc_arg(struct svc_rqst *rqstp) 655 { 656 struct svc_serv *serv = rqstp->rq_server; 657 struct xdr_buf *arg; 658 int pages; 659 int i; 660 661 /* now allocate needed pages. If we get a failure, sleep briefly */ 662 pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT; 663 if (pages > RPCSVC_MAXPAGES) { 664 pr_warn_once("svc: warning: pages=%u > RPCSVC_MAXPAGES=%lu\n", 665 pages, RPCSVC_MAXPAGES); 666 /* use as many pages as possible */ 667 pages = RPCSVC_MAXPAGES; 668 } 669 for (i = 0; i < pages ; i++) 670 while (rqstp->rq_pages[i] == NULL) { 671 struct page *p = alloc_page(GFP_KERNEL); 672 if (!p) { 673 set_current_state(TASK_INTERRUPTIBLE); 674 if (signalled() || kthread_should_stop()) { 675 set_current_state(TASK_RUNNING); 676 return -EINTR; 677 } 678 schedule_timeout(msecs_to_jiffies(500)); 679 } 680 rqstp->rq_pages[i] = p; 681 } 682 rqstp->rq_page_end = &rqstp->rq_pages[i]; 683 rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */ 684 685 /* Make arg->head point to first page and arg->pages point to rest */ 686 arg = &rqstp->rq_arg; 687 arg->head[0].iov_base = page_address(rqstp->rq_pages[0]); 688 arg->head[0].iov_len = PAGE_SIZE; 689 arg->pages = rqstp->rq_pages + 1; 690 arg->page_base = 0; 691 /* save at least one page for response */ 692 arg->page_len = (pages-2)*PAGE_SIZE; 693 arg->len = (pages-1)*PAGE_SIZE; 694 arg->tail[0].iov_len = 0; 695 return 0; 696 } 697 698 static bool 699 rqst_should_sleep(struct svc_rqst *rqstp) 700 { 701 struct svc_pool *pool = rqstp->rq_pool; 702 703 /* did someone call svc_wake_up? */ 704 if (test_and_clear_bit(SP_TASK_PENDING, &pool->sp_flags)) 705 return false; 706 707 /* was a socket queued? */ 708 if (!list_empty(&pool->sp_sockets)) 709 return false; 710 711 /* are we shutting down? */ 712 if (signalled() || kthread_should_stop()) 713 return false; 714 715 /* are we freezing? */ 716 if (freezing(current)) 717 return false; 718 719 return true; 720 } 721 722 static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout) 723 { 724 struct svc_xprt *xprt; 725 struct svc_pool *pool = rqstp->rq_pool; 726 long time_left = 0; 727 728 /* rq_xprt should be clear on entry */ 729 WARN_ON_ONCE(rqstp->rq_xprt); 730 731 /* Normally we will wait up to 5 seconds for any required 732 * cache information to be provided. 733 */ 734 rqstp->rq_chandle.thread_wait = 5*HZ; 735 736 xprt = svc_xprt_dequeue(pool); 737 if (xprt) { 738 rqstp->rq_xprt = xprt; 739 740 /* As there is a shortage of threads and this request 741 * had to be queued, don't allow the thread to wait so 742 * long for cache updates. 743 */ 744 rqstp->rq_chandle.thread_wait = 1*HZ; 745 clear_bit(SP_TASK_PENDING, &pool->sp_flags); 746 return xprt; 747 } 748 749 /* 750 * We have to be able to interrupt this wait 751 * to bring down the daemons ... 752 */ 753 set_current_state(TASK_INTERRUPTIBLE); 754 clear_bit(RQ_BUSY, &rqstp->rq_flags); 755 smp_mb(); 756 757 if (likely(rqst_should_sleep(rqstp))) 758 time_left = schedule_timeout(timeout); 759 else 760 __set_current_state(TASK_RUNNING); 761 762 try_to_freeze(); 763 764 spin_lock_bh(&rqstp->rq_lock); 765 set_bit(RQ_BUSY, &rqstp->rq_flags); 766 spin_unlock_bh(&rqstp->rq_lock); 767 768 xprt = rqstp->rq_xprt; 769 if (xprt != NULL) 770 return xprt; 771 772 if (!time_left) 773 atomic_long_inc(&pool->sp_stats.threads_timedout); 774 775 if (signalled() || kthread_should_stop()) 776 return ERR_PTR(-EINTR); 777 return ERR_PTR(-EAGAIN); 778 } 779 780 static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt) 781 { 782 spin_lock_bh(&serv->sv_lock); 783 set_bit(XPT_TEMP, &newxpt->xpt_flags); 784 list_add(&newxpt->xpt_list, &serv->sv_tempsocks); 785 serv->sv_tmpcnt++; 786 if (serv->sv_temptimer.function == NULL) { 787 /* setup timer to age temp transports */ 788 setup_timer(&serv->sv_temptimer, svc_age_temp_xprts, 789 (unsigned long)serv); 790 mod_timer(&serv->sv_temptimer, 791 jiffies + svc_conn_age_period * HZ); 792 } 793 spin_unlock_bh(&serv->sv_lock); 794 svc_xprt_received(newxpt); 795 } 796 797 static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt) 798 { 799 struct svc_serv *serv = rqstp->rq_server; 800 int len = 0; 801 802 if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) { 803 dprintk("svc_recv: found XPT_CLOSE\n"); 804 if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags)) 805 xprt->xpt_ops->xpo_kill_temp_xprt(xprt); 806 svc_delete_xprt(xprt); 807 /* Leave XPT_BUSY set on the dead xprt: */ 808 goto out; 809 } 810 if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) { 811 struct svc_xprt *newxpt; 812 /* 813 * We know this module_get will succeed because the 814 * listener holds a reference too 815 */ 816 __module_get(xprt->xpt_class->xcl_owner); 817 svc_check_conn_limits(xprt->xpt_server); 818 newxpt = xprt->xpt_ops->xpo_accept(xprt); 819 if (newxpt) 820 svc_add_new_temp_xprt(serv, newxpt); 821 else 822 module_put(xprt->xpt_class->xcl_owner); 823 } else if (svc_xprt_reserve_slot(rqstp, xprt)) { 824 /* XPT_DATA|XPT_DEFERRED case: */ 825 dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n", 826 rqstp, rqstp->rq_pool->sp_id, xprt, 827 kref_read(&xprt->xpt_ref)); 828 rqstp->rq_deferred = svc_deferred_dequeue(xprt); 829 if (rqstp->rq_deferred) 830 len = svc_deferred_recv(rqstp); 831 else 832 len = xprt->xpt_ops->xpo_recvfrom(rqstp); 833 dprintk("svc: got len=%d\n", len); 834 rqstp->rq_reserved = serv->sv_max_mesg; 835 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved); 836 } 837 /* clear XPT_BUSY: */ 838 svc_xprt_received(xprt); 839 out: 840 trace_svc_handle_xprt(xprt, len); 841 return len; 842 } 843 844 /* 845 * Receive the next request on any transport. This code is carefully 846 * organised not to touch any cachelines in the shared svc_serv 847 * structure, only cachelines in the local svc_pool. 848 */ 849 int svc_recv(struct svc_rqst *rqstp, long timeout) 850 { 851 struct svc_xprt *xprt = NULL; 852 struct svc_serv *serv = rqstp->rq_server; 853 int len, err; 854 855 dprintk("svc: server %p waiting for data (to = %ld)\n", 856 rqstp, timeout); 857 858 if (rqstp->rq_xprt) 859 printk(KERN_ERR 860 "svc_recv: service %p, transport not NULL!\n", 861 rqstp); 862 863 err = svc_alloc_arg(rqstp); 864 if (err) 865 goto out; 866 867 try_to_freeze(); 868 cond_resched(); 869 err = -EINTR; 870 if (signalled() || kthread_should_stop()) 871 goto out; 872 873 xprt = svc_get_next_xprt(rqstp, timeout); 874 if (IS_ERR(xprt)) { 875 err = PTR_ERR(xprt); 876 goto out; 877 } 878 879 len = svc_handle_xprt(rqstp, xprt); 880 881 /* No data, incomplete (TCP) read, or accept() */ 882 err = -EAGAIN; 883 if (len <= 0) 884 goto out_release; 885 886 clear_bit(XPT_OLD, &xprt->xpt_flags); 887 888 if (xprt->xpt_ops->xpo_secure_port(rqstp)) 889 set_bit(RQ_SECURE, &rqstp->rq_flags); 890 else 891 clear_bit(RQ_SECURE, &rqstp->rq_flags); 892 rqstp->rq_chandle.defer = svc_defer; 893 rqstp->rq_xid = svc_getu32(&rqstp->rq_arg.head[0]); 894 895 if (serv->sv_stats) 896 serv->sv_stats->netcnt++; 897 trace_svc_recv(rqstp, len); 898 return len; 899 out_release: 900 rqstp->rq_res.len = 0; 901 svc_xprt_release(rqstp); 902 out: 903 trace_svc_recv(rqstp, err); 904 return err; 905 } 906 EXPORT_SYMBOL_GPL(svc_recv); 907 908 /* 909 * Drop request 910 */ 911 void svc_drop(struct svc_rqst *rqstp) 912 { 913 trace_svc_drop(rqstp); 914 dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt); 915 svc_xprt_release(rqstp); 916 } 917 EXPORT_SYMBOL_GPL(svc_drop); 918 919 /* 920 * Return reply to client. 921 */ 922 int svc_send(struct svc_rqst *rqstp) 923 { 924 struct svc_xprt *xprt; 925 int len = -EFAULT; 926 struct xdr_buf *xb; 927 928 xprt = rqstp->rq_xprt; 929 if (!xprt) 930 goto out; 931 932 /* release the receive skb before sending the reply */ 933 rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp); 934 935 /* calculate over-all length */ 936 xb = &rqstp->rq_res; 937 xb->len = xb->head[0].iov_len + 938 xb->page_len + 939 xb->tail[0].iov_len; 940 941 /* Grab mutex to serialize outgoing data. */ 942 mutex_lock(&xprt->xpt_mutex); 943 if (test_bit(XPT_DEAD, &xprt->xpt_flags) 944 || test_bit(XPT_CLOSE, &xprt->xpt_flags)) 945 len = -ENOTCONN; 946 else 947 len = xprt->xpt_ops->xpo_sendto(rqstp); 948 mutex_unlock(&xprt->xpt_mutex); 949 rpc_wake_up(&xprt->xpt_bc_pending); 950 svc_xprt_release(rqstp); 951 952 if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN) 953 len = 0; 954 out: 955 trace_svc_send(rqstp, len); 956 return len; 957 } 958 959 /* 960 * Timer function to close old temporary transports, using 961 * a mark-and-sweep algorithm. 962 */ 963 static void svc_age_temp_xprts(unsigned long closure) 964 { 965 struct svc_serv *serv = (struct svc_serv *)closure; 966 struct svc_xprt *xprt; 967 struct list_head *le, *next; 968 969 dprintk("svc_age_temp_xprts\n"); 970 971 if (!spin_trylock_bh(&serv->sv_lock)) { 972 /* busy, try again 1 sec later */ 973 dprintk("svc_age_temp_xprts: busy\n"); 974 mod_timer(&serv->sv_temptimer, jiffies + HZ); 975 return; 976 } 977 978 list_for_each_safe(le, next, &serv->sv_tempsocks) { 979 xprt = list_entry(le, struct svc_xprt, xpt_list); 980 981 /* First time through, just mark it OLD. Second time 982 * through, close it. */ 983 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags)) 984 continue; 985 if (kref_read(&xprt->xpt_ref) > 1 || 986 test_bit(XPT_BUSY, &xprt->xpt_flags)) 987 continue; 988 list_del_init(le); 989 set_bit(XPT_CLOSE, &xprt->xpt_flags); 990 dprintk("queuing xprt %p for closing\n", xprt); 991 992 /* a thread will dequeue and close it soon */ 993 svc_xprt_enqueue(xprt); 994 } 995 spin_unlock_bh(&serv->sv_lock); 996 997 mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ); 998 } 999 1000 /* Close temporary transports whose xpt_local matches server_addr immediately 1001 * instead of waiting for them to be picked up by the timer. 1002 * 1003 * This is meant to be called from a notifier_block that runs when an ip 1004 * address is deleted. 1005 */ 1006 void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr) 1007 { 1008 struct svc_xprt *xprt; 1009 struct list_head *le, *next; 1010 LIST_HEAD(to_be_closed); 1011 1012 spin_lock_bh(&serv->sv_lock); 1013 list_for_each_safe(le, next, &serv->sv_tempsocks) { 1014 xprt = list_entry(le, struct svc_xprt, xpt_list); 1015 if (rpc_cmp_addr(server_addr, (struct sockaddr *) 1016 &xprt->xpt_local)) { 1017 dprintk("svc_age_temp_xprts_now: found %p\n", xprt); 1018 list_move(le, &to_be_closed); 1019 } 1020 } 1021 spin_unlock_bh(&serv->sv_lock); 1022 1023 while (!list_empty(&to_be_closed)) { 1024 le = to_be_closed.next; 1025 list_del_init(le); 1026 xprt = list_entry(le, struct svc_xprt, xpt_list); 1027 set_bit(XPT_CLOSE, &xprt->xpt_flags); 1028 set_bit(XPT_KILL_TEMP, &xprt->xpt_flags); 1029 dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n", 1030 xprt); 1031 svc_xprt_enqueue(xprt); 1032 } 1033 } 1034 EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now); 1035 1036 static void call_xpt_users(struct svc_xprt *xprt) 1037 { 1038 struct svc_xpt_user *u; 1039 1040 spin_lock(&xprt->xpt_lock); 1041 while (!list_empty(&xprt->xpt_users)) { 1042 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list); 1043 list_del(&u->list); 1044 u->callback(u); 1045 } 1046 spin_unlock(&xprt->xpt_lock); 1047 } 1048 1049 /* 1050 * Remove a dead transport 1051 */ 1052 static void svc_delete_xprt(struct svc_xprt *xprt) 1053 { 1054 struct svc_serv *serv = xprt->xpt_server; 1055 struct svc_deferred_req *dr; 1056 1057 /* Only do this once */ 1058 if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags)) 1059 BUG(); 1060 1061 dprintk("svc: svc_delete_xprt(%p)\n", xprt); 1062 xprt->xpt_ops->xpo_detach(xprt); 1063 1064 spin_lock_bh(&serv->sv_lock); 1065 list_del_init(&xprt->xpt_list); 1066 WARN_ON_ONCE(!list_empty(&xprt->xpt_ready)); 1067 if (test_bit(XPT_TEMP, &xprt->xpt_flags)) 1068 serv->sv_tmpcnt--; 1069 spin_unlock_bh(&serv->sv_lock); 1070 1071 while ((dr = svc_deferred_dequeue(xprt)) != NULL) 1072 kfree(dr); 1073 1074 call_xpt_users(xprt); 1075 svc_xprt_put(xprt); 1076 } 1077 1078 void svc_close_xprt(struct svc_xprt *xprt) 1079 { 1080 set_bit(XPT_CLOSE, &xprt->xpt_flags); 1081 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) 1082 /* someone else will have to effect the close */ 1083 return; 1084 /* 1085 * We expect svc_close_xprt() to work even when no threads are 1086 * running (e.g., while configuring the server before starting 1087 * any threads), so if the transport isn't busy, we delete 1088 * it ourself: 1089 */ 1090 svc_delete_xprt(xprt); 1091 } 1092 EXPORT_SYMBOL_GPL(svc_close_xprt); 1093 1094 static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net) 1095 { 1096 struct svc_xprt *xprt; 1097 int ret = 0; 1098 1099 spin_lock(&serv->sv_lock); 1100 list_for_each_entry(xprt, xprt_list, xpt_list) { 1101 if (xprt->xpt_net != net) 1102 continue; 1103 ret++; 1104 set_bit(XPT_CLOSE, &xprt->xpt_flags); 1105 svc_xprt_enqueue(xprt); 1106 } 1107 spin_unlock(&serv->sv_lock); 1108 return ret; 1109 } 1110 1111 static struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net) 1112 { 1113 struct svc_pool *pool; 1114 struct svc_xprt *xprt; 1115 struct svc_xprt *tmp; 1116 int i; 1117 1118 for (i = 0; i < serv->sv_nrpools; i++) { 1119 pool = &serv->sv_pools[i]; 1120 1121 spin_lock_bh(&pool->sp_lock); 1122 list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) { 1123 if (xprt->xpt_net != net) 1124 continue; 1125 list_del_init(&xprt->xpt_ready); 1126 spin_unlock_bh(&pool->sp_lock); 1127 return xprt; 1128 } 1129 spin_unlock_bh(&pool->sp_lock); 1130 } 1131 return NULL; 1132 } 1133 1134 static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net) 1135 { 1136 struct svc_xprt *xprt; 1137 1138 while ((xprt = svc_dequeue_net(serv, net))) { 1139 set_bit(XPT_CLOSE, &xprt->xpt_flags); 1140 svc_delete_xprt(xprt); 1141 } 1142 } 1143 1144 /* 1145 * Server threads may still be running (especially in the case where the 1146 * service is still running in other network namespaces). 1147 * 1148 * So we shut down sockets the same way we would on a running server, by 1149 * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do 1150 * the close. In the case there are no such other threads, 1151 * threads running, svc_clean_up_xprts() does a simple version of a 1152 * server's main event loop, and in the case where there are other 1153 * threads, we may need to wait a little while and then check again to 1154 * see if they're done. 1155 */ 1156 void svc_close_net(struct svc_serv *serv, struct net *net) 1157 { 1158 int delay = 0; 1159 1160 while (svc_close_list(serv, &serv->sv_permsocks, net) + 1161 svc_close_list(serv, &serv->sv_tempsocks, net)) { 1162 1163 svc_clean_up_xprts(serv, net); 1164 msleep(delay++); 1165 } 1166 } 1167 1168 /* 1169 * Handle defer and revisit of requests 1170 */ 1171 1172 static void svc_revisit(struct cache_deferred_req *dreq, int too_many) 1173 { 1174 struct svc_deferred_req *dr = 1175 container_of(dreq, struct svc_deferred_req, handle); 1176 struct svc_xprt *xprt = dr->xprt; 1177 1178 spin_lock(&xprt->xpt_lock); 1179 set_bit(XPT_DEFERRED, &xprt->xpt_flags); 1180 if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) { 1181 spin_unlock(&xprt->xpt_lock); 1182 dprintk("revisit canceled\n"); 1183 svc_xprt_put(xprt); 1184 trace_svc_drop_deferred(dr); 1185 kfree(dr); 1186 return; 1187 } 1188 dprintk("revisit queued\n"); 1189 dr->xprt = NULL; 1190 list_add(&dr->handle.recent, &xprt->xpt_deferred); 1191 spin_unlock(&xprt->xpt_lock); 1192 svc_xprt_enqueue(xprt); 1193 svc_xprt_put(xprt); 1194 } 1195 1196 /* 1197 * Save the request off for later processing. The request buffer looks 1198 * like this: 1199 * 1200 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail> 1201 * 1202 * This code can only handle requests that consist of an xprt-header 1203 * and rpc-header. 1204 */ 1205 static struct cache_deferred_req *svc_defer(struct cache_req *req) 1206 { 1207 struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle); 1208 struct svc_deferred_req *dr; 1209 1210 if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags)) 1211 return NULL; /* if more than a page, give up FIXME */ 1212 if (rqstp->rq_deferred) { 1213 dr = rqstp->rq_deferred; 1214 rqstp->rq_deferred = NULL; 1215 } else { 1216 size_t skip; 1217 size_t size; 1218 /* FIXME maybe discard if size too large */ 1219 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len; 1220 dr = kmalloc(size, GFP_KERNEL); 1221 if (dr == NULL) 1222 return NULL; 1223 1224 dr->handle.owner = rqstp->rq_server; 1225 dr->prot = rqstp->rq_prot; 1226 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen); 1227 dr->addrlen = rqstp->rq_addrlen; 1228 dr->daddr = rqstp->rq_daddr; 1229 dr->argslen = rqstp->rq_arg.len >> 2; 1230 dr->xprt_hlen = rqstp->rq_xprt_hlen; 1231 1232 /* back up head to the start of the buffer and copy */ 1233 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len; 1234 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip, 1235 dr->argslen << 2); 1236 } 1237 svc_xprt_get(rqstp->rq_xprt); 1238 dr->xprt = rqstp->rq_xprt; 1239 set_bit(RQ_DROPME, &rqstp->rq_flags); 1240 1241 dr->handle.revisit = svc_revisit; 1242 trace_svc_defer(rqstp); 1243 return &dr->handle; 1244 } 1245 1246 /* 1247 * recv data from a deferred request into an active one 1248 */ 1249 static int svc_deferred_recv(struct svc_rqst *rqstp) 1250 { 1251 struct svc_deferred_req *dr = rqstp->rq_deferred; 1252 1253 /* setup iov_base past transport header */ 1254 rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2); 1255 /* The iov_len does not include the transport header bytes */ 1256 rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen; 1257 rqstp->rq_arg.page_len = 0; 1258 /* The rq_arg.len includes the transport header bytes */ 1259 rqstp->rq_arg.len = dr->argslen<<2; 1260 rqstp->rq_prot = dr->prot; 1261 memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen); 1262 rqstp->rq_addrlen = dr->addrlen; 1263 /* Save off transport header len in case we get deferred again */ 1264 rqstp->rq_xprt_hlen = dr->xprt_hlen; 1265 rqstp->rq_daddr = dr->daddr; 1266 rqstp->rq_respages = rqstp->rq_pages; 1267 return (dr->argslen<<2) - dr->xprt_hlen; 1268 } 1269 1270 1271 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt) 1272 { 1273 struct svc_deferred_req *dr = NULL; 1274 1275 if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags)) 1276 return NULL; 1277 spin_lock(&xprt->xpt_lock); 1278 if (!list_empty(&xprt->xpt_deferred)) { 1279 dr = list_entry(xprt->xpt_deferred.next, 1280 struct svc_deferred_req, 1281 handle.recent); 1282 list_del_init(&dr->handle.recent); 1283 trace_svc_revisit_deferred(dr); 1284 } else 1285 clear_bit(XPT_DEFERRED, &xprt->xpt_flags); 1286 spin_unlock(&xprt->xpt_lock); 1287 return dr; 1288 } 1289 1290 /** 1291 * svc_find_xprt - find an RPC transport instance 1292 * @serv: pointer to svc_serv to search 1293 * @xcl_name: C string containing transport's class name 1294 * @net: owner net pointer 1295 * @af: Address family of transport's local address 1296 * @port: transport's IP port number 1297 * 1298 * Return the transport instance pointer for the endpoint accepting 1299 * connections/peer traffic from the specified transport class, 1300 * address family and port. 1301 * 1302 * Specifying 0 for the address family or port is effectively a 1303 * wild-card, and will result in matching the first transport in the 1304 * service's list that has a matching class name. 1305 */ 1306 struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name, 1307 struct net *net, const sa_family_t af, 1308 const unsigned short port) 1309 { 1310 struct svc_xprt *xprt; 1311 struct svc_xprt *found = NULL; 1312 1313 /* Sanity check the args */ 1314 if (serv == NULL || xcl_name == NULL) 1315 return found; 1316 1317 spin_lock_bh(&serv->sv_lock); 1318 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) { 1319 if (xprt->xpt_net != net) 1320 continue; 1321 if (strcmp(xprt->xpt_class->xcl_name, xcl_name)) 1322 continue; 1323 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family) 1324 continue; 1325 if (port != 0 && port != svc_xprt_local_port(xprt)) 1326 continue; 1327 found = xprt; 1328 svc_xprt_get(xprt); 1329 break; 1330 } 1331 spin_unlock_bh(&serv->sv_lock); 1332 return found; 1333 } 1334 EXPORT_SYMBOL_GPL(svc_find_xprt); 1335 1336 static int svc_one_xprt_name(const struct svc_xprt *xprt, 1337 char *pos, int remaining) 1338 { 1339 int len; 1340 1341 len = snprintf(pos, remaining, "%s %u\n", 1342 xprt->xpt_class->xcl_name, 1343 svc_xprt_local_port(xprt)); 1344 if (len >= remaining) 1345 return -ENAMETOOLONG; 1346 return len; 1347 } 1348 1349 /** 1350 * svc_xprt_names - format a buffer with a list of transport names 1351 * @serv: pointer to an RPC service 1352 * @buf: pointer to a buffer to be filled in 1353 * @buflen: length of buffer to be filled in 1354 * 1355 * Fills in @buf with a string containing a list of transport names, 1356 * each name terminated with '\n'. 1357 * 1358 * Returns positive length of the filled-in string on success; otherwise 1359 * a negative errno value is returned if an error occurs. 1360 */ 1361 int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen) 1362 { 1363 struct svc_xprt *xprt; 1364 int len, totlen; 1365 char *pos; 1366 1367 /* Sanity check args */ 1368 if (!serv) 1369 return 0; 1370 1371 spin_lock_bh(&serv->sv_lock); 1372 1373 pos = buf; 1374 totlen = 0; 1375 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) { 1376 len = svc_one_xprt_name(xprt, pos, buflen - totlen); 1377 if (len < 0) { 1378 *buf = '\0'; 1379 totlen = len; 1380 } 1381 if (len <= 0) 1382 break; 1383 1384 pos += len; 1385 totlen += len; 1386 } 1387 1388 spin_unlock_bh(&serv->sv_lock); 1389 return totlen; 1390 } 1391 EXPORT_SYMBOL_GPL(svc_xprt_names); 1392 1393 1394 /*----------------------------------------------------------------------------*/ 1395 1396 static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos) 1397 { 1398 unsigned int pidx = (unsigned int)*pos; 1399 struct svc_serv *serv = m->private; 1400 1401 dprintk("svc_pool_stats_start, *pidx=%u\n", pidx); 1402 1403 if (!pidx) 1404 return SEQ_START_TOKEN; 1405 return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]); 1406 } 1407 1408 static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos) 1409 { 1410 struct svc_pool *pool = p; 1411 struct svc_serv *serv = m->private; 1412 1413 dprintk("svc_pool_stats_next, *pos=%llu\n", *pos); 1414 1415 if (p == SEQ_START_TOKEN) { 1416 pool = &serv->sv_pools[0]; 1417 } else { 1418 unsigned int pidx = (pool - &serv->sv_pools[0]); 1419 if (pidx < serv->sv_nrpools-1) 1420 pool = &serv->sv_pools[pidx+1]; 1421 else 1422 pool = NULL; 1423 } 1424 ++*pos; 1425 return pool; 1426 } 1427 1428 static void svc_pool_stats_stop(struct seq_file *m, void *p) 1429 { 1430 } 1431 1432 static int svc_pool_stats_show(struct seq_file *m, void *p) 1433 { 1434 struct svc_pool *pool = p; 1435 1436 if (p == SEQ_START_TOKEN) { 1437 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n"); 1438 return 0; 1439 } 1440 1441 seq_printf(m, "%u %lu %lu %lu %lu\n", 1442 pool->sp_id, 1443 (unsigned long)atomic_long_read(&pool->sp_stats.packets), 1444 pool->sp_stats.sockets_queued, 1445 (unsigned long)atomic_long_read(&pool->sp_stats.threads_woken), 1446 (unsigned long)atomic_long_read(&pool->sp_stats.threads_timedout)); 1447 1448 return 0; 1449 } 1450 1451 static const struct seq_operations svc_pool_stats_seq_ops = { 1452 .start = svc_pool_stats_start, 1453 .next = svc_pool_stats_next, 1454 .stop = svc_pool_stats_stop, 1455 .show = svc_pool_stats_show, 1456 }; 1457 1458 int svc_pool_stats_open(struct svc_serv *serv, struct file *file) 1459 { 1460 int err; 1461 1462 err = seq_open(file, &svc_pool_stats_seq_ops); 1463 if (!err) 1464 ((struct seq_file *) file->private_data)->private = serv; 1465 return err; 1466 } 1467 EXPORT_SYMBOL(svc_pool_stats_open); 1468 1469 /*----------------------------------------------------------------------------*/ 1470