1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* Client connection-specific management code. 3 * 4 * Copyright (C) 2016, 2020 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 * 7 * Client connections need to be cached for a little while after they've made a 8 * call so as to handle retransmitted DATA packets in case the server didn't 9 * receive the final ACK or terminating ABORT we sent it. 10 * 11 * There are flags of relevance to the cache: 12 * 13 * (2) DONT_REUSE - The connection should be discarded as soon as possible and 14 * should not be reused. This is set when an exclusive connection is used 15 * or a call ID counter overflows. 16 * 17 * The caching state may only be changed if the cache lock is held. 18 * 19 * There are two idle client connection expiry durations. If the total number 20 * of connections is below the reap threshold, we use the normal duration; if 21 * it's above, we use the fast duration. 22 */ 23 24 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 25 26 #include <linux/slab.h> 27 #include <linux/idr.h> 28 #include <linux/timer.h> 29 #include <linux/sched/signal.h> 30 31 #include "ar-internal.h" 32 33 __read_mostly unsigned int rxrpc_reap_client_connections = 900; 34 __read_mostly unsigned long rxrpc_conn_idle_client_expiry = 2 * 60 * HZ; 35 __read_mostly unsigned long rxrpc_conn_idle_client_fast_expiry = 2 * HZ; 36 37 /* 38 * We use machine-unique IDs for our client connections. 39 */ 40 DEFINE_IDR(rxrpc_client_conn_ids); 41 static DEFINE_SPINLOCK(rxrpc_conn_id_lock); 42 43 /* 44 * Get a connection ID and epoch for a client connection from the global pool. 45 * The connection struct pointer is then recorded in the idr radix tree. The 46 * epoch doesn't change until the client is rebooted (or, at least, unless the 47 * module is unloaded). 48 */ 49 static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn, 50 gfp_t gfp) 51 { 52 struct rxrpc_net *rxnet = conn->params.local->rxnet; 53 int id; 54 55 _enter(""); 56 57 idr_preload(gfp); 58 spin_lock(&rxrpc_conn_id_lock); 59 60 id = idr_alloc_cyclic(&rxrpc_client_conn_ids, conn, 61 1, 0x40000000, GFP_NOWAIT); 62 if (id < 0) 63 goto error; 64 65 spin_unlock(&rxrpc_conn_id_lock); 66 idr_preload_end(); 67 68 conn->proto.epoch = rxnet->epoch; 69 conn->proto.cid = id << RXRPC_CIDSHIFT; 70 set_bit(RXRPC_CONN_HAS_IDR, &conn->flags); 71 _leave(" [CID %x]", conn->proto.cid); 72 return 0; 73 74 error: 75 spin_unlock(&rxrpc_conn_id_lock); 76 idr_preload_end(); 77 _leave(" = %d", id); 78 return id; 79 } 80 81 /* 82 * Release a connection ID for a client connection from the global pool. 83 */ 84 static void rxrpc_put_client_connection_id(struct rxrpc_connection *conn) 85 { 86 if (test_bit(RXRPC_CONN_HAS_IDR, &conn->flags)) { 87 spin_lock(&rxrpc_conn_id_lock); 88 idr_remove(&rxrpc_client_conn_ids, 89 conn->proto.cid >> RXRPC_CIDSHIFT); 90 spin_unlock(&rxrpc_conn_id_lock); 91 } 92 } 93 94 /* 95 * Destroy the client connection ID tree. 96 */ 97 void rxrpc_destroy_client_conn_ids(void) 98 { 99 struct rxrpc_connection *conn; 100 int id; 101 102 if (!idr_is_empty(&rxrpc_client_conn_ids)) { 103 idr_for_each_entry(&rxrpc_client_conn_ids, conn, id) { 104 pr_err("AF_RXRPC: Leaked client conn %p {%d}\n", 105 conn, atomic_read(&conn->usage)); 106 } 107 BUG(); 108 } 109 110 idr_destroy(&rxrpc_client_conn_ids); 111 } 112 113 /* 114 * Allocate a connection bundle. 115 */ 116 static struct rxrpc_bundle *rxrpc_alloc_bundle(struct rxrpc_conn_parameters *cp, 117 gfp_t gfp) 118 { 119 struct rxrpc_bundle *bundle; 120 121 bundle = kzalloc(sizeof(*bundle), gfp); 122 if (bundle) { 123 bundle->params = *cp; 124 rxrpc_get_peer(bundle->params.peer); 125 atomic_set(&bundle->usage, 1); 126 spin_lock_init(&bundle->channel_lock); 127 INIT_LIST_HEAD(&bundle->waiting_calls); 128 } 129 return bundle; 130 } 131 132 struct rxrpc_bundle *rxrpc_get_bundle(struct rxrpc_bundle *bundle) 133 { 134 atomic_inc(&bundle->usage); 135 return bundle; 136 } 137 138 static void rxrpc_free_bundle(struct rxrpc_bundle *bundle) 139 { 140 rxrpc_put_peer(bundle->params.peer); 141 kfree(bundle); 142 } 143 144 void rxrpc_put_bundle(struct rxrpc_bundle *bundle) 145 { 146 unsigned int d = bundle->debug_id; 147 unsigned int u = atomic_dec_return(&bundle->usage); 148 149 _debug("PUT B=%x %u", d, u); 150 if (u == 0) 151 rxrpc_free_bundle(bundle); 152 } 153 154 /* 155 * Allocate a client connection. 156 */ 157 static struct rxrpc_connection * 158 rxrpc_alloc_client_connection(struct rxrpc_bundle *bundle, gfp_t gfp) 159 { 160 struct rxrpc_connection *conn; 161 struct rxrpc_net *rxnet = bundle->params.local->rxnet; 162 int ret; 163 164 _enter(""); 165 166 conn = rxrpc_alloc_connection(gfp); 167 if (!conn) { 168 _leave(" = -ENOMEM"); 169 return ERR_PTR(-ENOMEM); 170 } 171 172 atomic_set(&conn->usage, 1); 173 conn->bundle = bundle; 174 conn->params = bundle->params; 175 conn->out_clientflag = RXRPC_CLIENT_INITIATED; 176 conn->state = RXRPC_CONN_CLIENT; 177 conn->service_id = conn->params.service_id; 178 179 ret = rxrpc_get_client_connection_id(conn, gfp); 180 if (ret < 0) 181 goto error_0; 182 183 ret = rxrpc_init_client_conn_security(conn); 184 if (ret < 0) 185 goto error_1; 186 187 atomic_inc(&rxnet->nr_conns); 188 write_lock(&rxnet->conn_lock); 189 list_add_tail(&conn->proc_link, &rxnet->conn_proc_list); 190 write_unlock(&rxnet->conn_lock); 191 192 rxrpc_get_bundle(bundle); 193 rxrpc_get_peer(conn->params.peer); 194 rxrpc_get_local(conn->params.local); 195 key_get(conn->params.key); 196 197 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_new_client, 198 atomic_read(&conn->usage), 199 __builtin_return_address(0)); 200 201 atomic_inc(&rxnet->nr_client_conns); 202 trace_rxrpc_client(conn, -1, rxrpc_client_alloc); 203 _leave(" = %p", conn); 204 return conn; 205 206 error_1: 207 rxrpc_put_client_connection_id(conn); 208 error_0: 209 kfree(conn); 210 _leave(" = %d", ret); 211 return ERR_PTR(ret); 212 } 213 214 /* 215 * Determine if a connection may be reused. 216 */ 217 static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn) 218 { 219 struct rxrpc_net *rxnet; 220 int id_cursor, id, distance, limit; 221 222 if (!conn) 223 goto dont_reuse; 224 225 rxnet = conn->params.local->rxnet; 226 if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags)) 227 goto dont_reuse; 228 229 if (conn->state != RXRPC_CONN_CLIENT || 230 conn->proto.epoch != rxnet->epoch) 231 goto mark_dont_reuse; 232 233 /* The IDR tree gets very expensive on memory if the connection IDs are 234 * widely scattered throughout the number space, so we shall want to 235 * kill off connections that, say, have an ID more than about four 236 * times the maximum number of client conns away from the current 237 * allocation point to try and keep the IDs concentrated. 238 */ 239 id_cursor = idr_get_cursor(&rxrpc_client_conn_ids); 240 id = conn->proto.cid >> RXRPC_CIDSHIFT; 241 distance = id - id_cursor; 242 if (distance < 0) 243 distance = -distance; 244 limit = max_t(unsigned long, atomic_read(&rxnet->nr_conns) * 4, 1024); 245 if (distance > limit) 246 goto mark_dont_reuse; 247 248 return true; 249 250 mark_dont_reuse: 251 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags); 252 dont_reuse: 253 return false; 254 } 255 256 /* 257 * Look up the conn bundle that matches the connection parameters, adding it if 258 * it doesn't yet exist. 259 */ 260 static struct rxrpc_bundle *rxrpc_look_up_bundle(struct rxrpc_conn_parameters *cp, 261 gfp_t gfp) 262 { 263 static atomic_t rxrpc_bundle_id; 264 struct rxrpc_bundle *bundle, *candidate; 265 struct rxrpc_local *local = cp->local; 266 struct rb_node *p, **pp, *parent; 267 long diff; 268 269 _enter("{%px,%x,%u,%u}", 270 cp->peer, key_serial(cp->key), cp->security_level, cp->upgrade); 271 272 if (cp->exclusive) 273 return rxrpc_alloc_bundle(cp, gfp); 274 275 /* First, see if the bundle is already there. */ 276 _debug("search 1"); 277 spin_lock(&local->client_bundles_lock); 278 p = local->client_bundles.rb_node; 279 while (p) { 280 bundle = rb_entry(p, struct rxrpc_bundle, local_node); 281 282 #define cmp(X) ((long)bundle->params.X - (long)cp->X) 283 diff = (cmp(peer) ?: 284 cmp(key) ?: 285 cmp(security_level) ?: 286 cmp(upgrade)); 287 #undef cmp 288 if (diff < 0) 289 p = p->rb_left; 290 else if (diff > 0) 291 p = p->rb_right; 292 else 293 goto found_bundle; 294 } 295 spin_unlock(&local->client_bundles_lock); 296 _debug("not found"); 297 298 /* It wasn't. We need to add one. */ 299 candidate = rxrpc_alloc_bundle(cp, gfp); 300 if (!candidate) 301 return NULL; 302 303 _debug("search 2"); 304 spin_lock(&local->client_bundles_lock); 305 pp = &local->client_bundles.rb_node; 306 parent = NULL; 307 while (*pp) { 308 parent = *pp; 309 bundle = rb_entry(parent, struct rxrpc_bundle, local_node); 310 311 #define cmp(X) ((long)bundle->params.X - (long)cp->X) 312 diff = (cmp(peer) ?: 313 cmp(key) ?: 314 cmp(security_level) ?: 315 cmp(upgrade)); 316 #undef cmp 317 if (diff < 0) 318 pp = &(*pp)->rb_left; 319 else if (diff > 0) 320 pp = &(*pp)->rb_right; 321 else 322 goto found_bundle_free; 323 } 324 325 _debug("new bundle"); 326 candidate->debug_id = atomic_inc_return(&rxrpc_bundle_id); 327 rb_link_node(&candidate->local_node, parent, pp); 328 rb_insert_color(&candidate->local_node, &local->client_bundles); 329 rxrpc_get_bundle(candidate); 330 spin_unlock(&local->client_bundles_lock); 331 _leave(" = %u [new]", candidate->debug_id); 332 return candidate; 333 334 found_bundle_free: 335 rxrpc_free_bundle(candidate); 336 found_bundle: 337 rxrpc_get_bundle(bundle); 338 spin_unlock(&local->client_bundles_lock); 339 _leave(" = %u [found]", bundle->debug_id); 340 return bundle; 341 } 342 343 /* 344 * Create or find a client bundle to use for a call. 345 * 346 * If we return with a connection, the call will be on its waiting list. It's 347 * left to the caller to assign a channel and wake up the call. 348 */ 349 static struct rxrpc_bundle *rxrpc_prep_call(struct rxrpc_sock *rx, 350 struct rxrpc_call *call, 351 struct rxrpc_conn_parameters *cp, 352 struct sockaddr_rxrpc *srx, 353 gfp_t gfp) 354 { 355 struct rxrpc_bundle *bundle; 356 357 _enter("{%d,%lx},", call->debug_id, call->user_call_ID); 358 359 cp->peer = rxrpc_lookup_peer(rx, cp->local, srx, gfp); 360 if (!cp->peer) 361 goto error; 362 363 call->cong_cwnd = cp->peer->cong_cwnd; 364 if (call->cong_cwnd >= call->cong_ssthresh) 365 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE; 366 else 367 call->cong_mode = RXRPC_CALL_SLOW_START; 368 if (cp->upgrade) 369 __set_bit(RXRPC_CALL_UPGRADE, &call->flags); 370 371 /* Find the client connection bundle. */ 372 bundle = rxrpc_look_up_bundle(cp, gfp); 373 if (!bundle) 374 goto error; 375 376 /* Get this call queued. Someone else may activate it whilst we're 377 * lining up a new connection, but that's fine. 378 */ 379 spin_lock(&bundle->channel_lock); 380 list_add_tail(&call->chan_wait_link, &bundle->waiting_calls); 381 spin_unlock(&bundle->channel_lock); 382 383 _leave(" = [B=%x]", bundle->debug_id); 384 return bundle; 385 386 error: 387 _leave(" = -ENOMEM"); 388 return ERR_PTR(-ENOMEM); 389 } 390 391 /* 392 * Allocate a new connection and add it into a bundle. 393 */ 394 static void rxrpc_add_conn_to_bundle(struct rxrpc_bundle *bundle, gfp_t gfp) 395 __releases(bundle->channel_lock) 396 { 397 struct rxrpc_connection *candidate = NULL, *old = NULL; 398 bool conflict; 399 int i; 400 401 _enter(""); 402 403 conflict = bundle->alloc_conn; 404 if (!conflict) 405 bundle->alloc_conn = true; 406 spin_unlock(&bundle->channel_lock); 407 if (conflict) { 408 _leave(" [conf]"); 409 return; 410 } 411 412 candidate = rxrpc_alloc_client_connection(bundle, gfp); 413 414 spin_lock(&bundle->channel_lock); 415 bundle->alloc_conn = false; 416 417 if (IS_ERR(candidate)) { 418 bundle->alloc_error = PTR_ERR(candidate); 419 spin_unlock(&bundle->channel_lock); 420 _leave(" [err %ld]", PTR_ERR(candidate)); 421 return; 422 } 423 424 bundle->alloc_error = 0; 425 426 for (i = 0; i < ARRAY_SIZE(bundle->conns); i++) { 427 unsigned int shift = i * RXRPC_MAXCALLS; 428 int j; 429 430 old = bundle->conns[i]; 431 if (!rxrpc_may_reuse_conn(old)) { 432 if (old) 433 trace_rxrpc_client(old, -1, rxrpc_client_replace); 434 candidate->bundle_shift = shift; 435 bundle->conns[i] = candidate; 436 for (j = 0; j < RXRPC_MAXCALLS; j++) 437 set_bit(shift + j, &bundle->avail_chans); 438 candidate = NULL; 439 break; 440 } 441 442 old = NULL; 443 } 444 445 spin_unlock(&bundle->channel_lock); 446 447 if (candidate) { 448 _debug("discard C=%x", candidate->debug_id); 449 trace_rxrpc_client(candidate, -1, rxrpc_client_duplicate); 450 rxrpc_put_connection(candidate); 451 } 452 453 rxrpc_put_connection(old); 454 _leave(""); 455 } 456 457 /* 458 * Add a connection to a bundle if there are no usable connections or we have 459 * connections waiting for extra capacity. 460 */ 461 static void rxrpc_maybe_add_conn(struct rxrpc_bundle *bundle, gfp_t gfp) 462 { 463 struct rxrpc_call *call; 464 int i, usable; 465 466 _enter(""); 467 468 spin_lock(&bundle->channel_lock); 469 470 /* See if there are any usable connections. */ 471 usable = 0; 472 for (i = 0; i < ARRAY_SIZE(bundle->conns); i++) 473 if (rxrpc_may_reuse_conn(bundle->conns[i])) 474 usable++; 475 476 if (!usable && !list_empty(&bundle->waiting_calls)) { 477 call = list_first_entry(&bundle->waiting_calls, 478 struct rxrpc_call, chan_wait_link); 479 if (test_bit(RXRPC_CALL_UPGRADE, &call->flags)) 480 bundle->try_upgrade = true; 481 } 482 483 if (!usable) 484 goto alloc_conn; 485 486 if (!bundle->avail_chans && 487 !bundle->try_upgrade && 488 !list_empty(&bundle->waiting_calls) && 489 usable < ARRAY_SIZE(bundle->conns)) 490 goto alloc_conn; 491 492 spin_unlock(&bundle->channel_lock); 493 _leave(""); 494 return; 495 496 alloc_conn: 497 return rxrpc_add_conn_to_bundle(bundle, gfp); 498 } 499 500 /* 501 * Assign a channel to the call at the front of the queue and wake the call up. 502 * We don't increment the callNumber counter until this number has been exposed 503 * to the world. 504 */ 505 static void rxrpc_activate_one_channel(struct rxrpc_connection *conn, 506 unsigned int channel) 507 { 508 struct rxrpc_channel *chan = &conn->channels[channel]; 509 struct rxrpc_bundle *bundle = conn->bundle; 510 struct rxrpc_call *call = list_entry(bundle->waiting_calls.next, 511 struct rxrpc_call, chan_wait_link); 512 u32 call_id = chan->call_counter + 1; 513 514 _enter("C=%x,%u", conn->debug_id, channel); 515 516 trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate); 517 518 /* Cancel the final ACK on the previous call if it hasn't been sent yet 519 * as the DATA packet will implicitly ACK it. 520 */ 521 clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags); 522 clear_bit(conn->bundle_shift + channel, &bundle->avail_chans); 523 524 rxrpc_see_call(call); 525 list_del_init(&call->chan_wait_link); 526 call->peer = rxrpc_get_peer(conn->params.peer); 527 call->conn = rxrpc_get_connection(conn); 528 call->cid = conn->proto.cid | channel; 529 call->call_id = call_id; 530 call->security = conn->security; 531 call->security_ix = conn->security_ix; 532 call->service_id = conn->service_id; 533 534 trace_rxrpc_connect_call(call); 535 _net("CONNECT call %08x:%08x as call %d on conn %d", 536 call->cid, call->call_id, call->debug_id, conn->debug_id); 537 538 write_lock_bh(&call->state_lock); 539 call->state = RXRPC_CALL_CLIENT_SEND_REQUEST; 540 write_unlock_bh(&call->state_lock); 541 542 /* Paired with the read barrier in rxrpc_connect_call(). This orders 543 * cid and epoch in the connection wrt to call_id without the need to 544 * take the channel_lock. 545 * 546 * We provisionally assign a callNumber at this point, but we don't 547 * confirm it until the call is about to be exposed. 548 * 549 * TODO: Pair with a barrier in the data_ready handler when that looks 550 * at the call ID through a connection channel. 551 */ 552 smp_wmb(); 553 554 chan->call_id = call_id; 555 chan->call_debug_id = call->debug_id; 556 rcu_assign_pointer(chan->call, call); 557 wake_up(&call->waitq); 558 } 559 560 /* 561 * Remove a connection from the idle list if it's on it. 562 */ 563 static void rxrpc_unidle_conn(struct rxrpc_bundle *bundle, struct rxrpc_connection *conn) 564 { 565 struct rxrpc_net *rxnet = bundle->params.local->rxnet; 566 bool drop_ref; 567 568 if (!list_empty(&conn->cache_link)) { 569 drop_ref = false; 570 spin_lock(&rxnet->client_conn_cache_lock); 571 if (!list_empty(&conn->cache_link)) { 572 list_del_init(&conn->cache_link); 573 drop_ref = true; 574 } 575 spin_unlock(&rxnet->client_conn_cache_lock); 576 if (drop_ref) 577 rxrpc_put_connection(conn); 578 } 579 } 580 581 /* 582 * Assign channels and callNumbers to waiting calls with channel_lock 583 * held by caller. 584 */ 585 static void rxrpc_activate_channels_locked(struct rxrpc_bundle *bundle) 586 { 587 struct rxrpc_connection *conn; 588 unsigned long avail, mask; 589 unsigned int channel, slot; 590 591 if (bundle->try_upgrade) 592 mask = 1; 593 else 594 mask = ULONG_MAX; 595 596 while (!list_empty(&bundle->waiting_calls)) { 597 avail = bundle->avail_chans & mask; 598 if (!avail) 599 break; 600 channel = __ffs(avail); 601 clear_bit(channel, &bundle->avail_chans); 602 603 slot = channel / RXRPC_MAXCALLS; 604 conn = bundle->conns[slot]; 605 if (!conn) 606 break; 607 608 if (bundle->try_upgrade) 609 set_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags); 610 rxrpc_unidle_conn(bundle, conn); 611 612 channel &= (RXRPC_MAXCALLS - 1); 613 conn->act_chans |= 1 << channel; 614 rxrpc_activate_one_channel(conn, channel); 615 } 616 } 617 618 /* 619 * Assign channels and callNumbers to waiting calls. 620 */ 621 static void rxrpc_activate_channels(struct rxrpc_bundle *bundle) 622 { 623 _enter("B=%x", bundle->debug_id); 624 625 trace_rxrpc_client(NULL, -1, rxrpc_client_activate_chans); 626 627 if (!bundle->avail_chans) 628 return; 629 630 spin_lock(&bundle->channel_lock); 631 rxrpc_activate_channels_locked(bundle); 632 spin_unlock(&bundle->channel_lock); 633 _leave(""); 634 } 635 636 /* 637 * Wait for a callNumber and a channel to be granted to a call. 638 */ 639 static int rxrpc_wait_for_channel(struct rxrpc_bundle *bundle, 640 struct rxrpc_call *call, gfp_t gfp) 641 { 642 DECLARE_WAITQUEUE(myself, current); 643 int ret = 0; 644 645 _enter("%d", call->debug_id); 646 647 if (!gfpflags_allow_blocking(gfp)) { 648 rxrpc_maybe_add_conn(bundle, gfp); 649 rxrpc_activate_channels(bundle); 650 ret = bundle->alloc_error ?: -EAGAIN; 651 goto out; 652 } 653 654 add_wait_queue_exclusive(&call->waitq, &myself); 655 for (;;) { 656 rxrpc_maybe_add_conn(bundle, gfp); 657 rxrpc_activate_channels(bundle); 658 ret = bundle->alloc_error; 659 if (ret < 0) 660 break; 661 662 switch (call->interruptibility) { 663 case RXRPC_INTERRUPTIBLE: 664 case RXRPC_PREINTERRUPTIBLE: 665 set_current_state(TASK_INTERRUPTIBLE); 666 break; 667 case RXRPC_UNINTERRUPTIBLE: 668 default: 669 set_current_state(TASK_UNINTERRUPTIBLE); 670 break; 671 } 672 if (READ_ONCE(call->state) != RXRPC_CALL_CLIENT_AWAIT_CONN) 673 break; 674 if ((call->interruptibility == RXRPC_INTERRUPTIBLE || 675 call->interruptibility == RXRPC_PREINTERRUPTIBLE) && 676 signal_pending(current)) { 677 ret = -ERESTARTSYS; 678 break; 679 } 680 schedule(); 681 } 682 remove_wait_queue(&call->waitq, &myself); 683 __set_current_state(TASK_RUNNING); 684 685 out: 686 _leave(" = %d", ret); 687 return ret; 688 } 689 690 /* 691 * find a connection for a call 692 * - called in process context with IRQs enabled 693 */ 694 int rxrpc_connect_call(struct rxrpc_sock *rx, 695 struct rxrpc_call *call, 696 struct rxrpc_conn_parameters *cp, 697 struct sockaddr_rxrpc *srx, 698 gfp_t gfp) 699 { 700 struct rxrpc_bundle *bundle; 701 struct rxrpc_net *rxnet = cp->local->rxnet; 702 int ret = 0; 703 704 _enter("{%d,%lx},", call->debug_id, call->user_call_ID); 705 706 rxrpc_discard_expired_client_conns(&rxnet->client_conn_reaper); 707 708 bundle = rxrpc_prep_call(rx, call, cp, srx, gfp); 709 if (IS_ERR(bundle)) { 710 ret = PTR_ERR(bundle); 711 goto out; 712 } 713 714 if (call->state == RXRPC_CALL_CLIENT_AWAIT_CONN) { 715 ret = rxrpc_wait_for_channel(bundle, call, gfp); 716 if (ret < 0) 717 goto wait_failed; 718 } 719 720 granted_channel: 721 /* Paired with the write barrier in rxrpc_activate_one_channel(). */ 722 smp_rmb(); 723 724 out_put_bundle: 725 rxrpc_put_bundle(bundle); 726 out: 727 _leave(" = %d", ret); 728 return ret; 729 730 wait_failed: 731 spin_lock(&bundle->channel_lock); 732 list_del_init(&call->chan_wait_link); 733 spin_unlock(&bundle->channel_lock); 734 735 if (call->state != RXRPC_CALL_CLIENT_AWAIT_CONN) { 736 ret = 0; 737 goto granted_channel; 738 } 739 740 trace_rxrpc_client(call->conn, ret, rxrpc_client_chan_wait_failed); 741 rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR, 0, ret); 742 rxrpc_disconnect_client_call(bundle, call); 743 goto out_put_bundle; 744 } 745 746 /* 747 * Note that a call, and thus a connection, is about to be exposed to the 748 * world. 749 */ 750 void rxrpc_expose_client_call(struct rxrpc_call *call) 751 { 752 unsigned int channel = call->cid & RXRPC_CHANNELMASK; 753 struct rxrpc_connection *conn = call->conn; 754 struct rxrpc_channel *chan = &conn->channels[channel]; 755 756 if (!test_and_set_bit(RXRPC_CALL_EXPOSED, &call->flags)) { 757 /* Mark the call ID as being used. If the callNumber counter 758 * exceeds ~2 billion, we kill the connection after its 759 * outstanding calls have finished so that the counter doesn't 760 * wrap. 761 */ 762 chan->call_counter++; 763 if (chan->call_counter >= INT_MAX) 764 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags); 765 trace_rxrpc_client(conn, channel, rxrpc_client_exposed); 766 } 767 } 768 769 /* 770 * Set the reap timer. 771 */ 772 static void rxrpc_set_client_reap_timer(struct rxrpc_net *rxnet) 773 { 774 if (!rxnet->kill_all_client_conns) { 775 unsigned long now = jiffies; 776 unsigned long reap_at = now + rxrpc_conn_idle_client_expiry; 777 778 if (rxnet->live) 779 timer_reduce(&rxnet->client_conn_reap_timer, reap_at); 780 } 781 } 782 783 /* 784 * Disconnect a client call. 785 */ 786 void rxrpc_disconnect_client_call(struct rxrpc_bundle *bundle, struct rxrpc_call *call) 787 { 788 struct rxrpc_connection *conn; 789 struct rxrpc_channel *chan = NULL; 790 struct rxrpc_net *rxnet = bundle->params.local->rxnet; 791 unsigned int channel; 792 bool may_reuse; 793 u32 cid; 794 795 _enter("c=%x", call->debug_id); 796 797 spin_lock(&bundle->channel_lock); 798 set_bit(RXRPC_CALL_DISCONNECTED, &call->flags); 799 800 /* Calls that have never actually been assigned a channel can simply be 801 * discarded. 802 */ 803 conn = call->conn; 804 if (!conn) { 805 _debug("call is waiting"); 806 ASSERTCMP(call->call_id, ==, 0); 807 ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags)); 808 list_del_init(&call->chan_wait_link); 809 goto out; 810 } 811 812 cid = call->cid; 813 channel = cid & RXRPC_CHANNELMASK; 814 chan = &conn->channels[channel]; 815 trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect); 816 817 if (rcu_access_pointer(chan->call) != call) { 818 spin_unlock(&bundle->channel_lock); 819 BUG(); 820 } 821 822 may_reuse = rxrpc_may_reuse_conn(conn); 823 824 /* If a client call was exposed to the world, we save the result for 825 * retransmission. 826 * 827 * We use a barrier here so that the call number and abort code can be 828 * read without needing to take a lock. 829 * 830 * TODO: Make the incoming packet handler check this and handle 831 * terminal retransmission without requiring access to the call. 832 */ 833 if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) { 834 _debug("exposed %u,%u", call->call_id, call->abort_code); 835 __rxrpc_disconnect_call(conn, call); 836 837 if (test_and_clear_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) { 838 trace_rxrpc_client(conn, channel, rxrpc_client_to_active); 839 bundle->try_upgrade = false; 840 if (may_reuse) 841 rxrpc_activate_channels_locked(bundle); 842 } 843 844 } 845 846 /* See if we can pass the channel directly to another call. */ 847 if (may_reuse && !list_empty(&bundle->waiting_calls)) { 848 trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass); 849 rxrpc_activate_one_channel(conn, channel); 850 goto out; 851 } 852 853 /* Schedule the final ACK to be transmitted in a short while so that it 854 * can be skipped if we find a follow-on call. The first DATA packet 855 * of the follow on call will implicitly ACK this call. 856 */ 857 if (call->completion == RXRPC_CALL_SUCCEEDED && 858 test_bit(RXRPC_CALL_EXPOSED, &call->flags)) { 859 unsigned long final_ack_at = jiffies + 2; 860 861 WRITE_ONCE(chan->final_ack_at, final_ack_at); 862 smp_wmb(); /* vs rxrpc_process_delayed_final_acks() */ 863 set_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags); 864 rxrpc_reduce_conn_timer(conn, final_ack_at); 865 } 866 867 /* Deactivate the channel. */ 868 rcu_assign_pointer(chan->call, NULL); 869 set_bit(conn->bundle_shift + channel, &conn->bundle->avail_chans); 870 conn->act_chans &= ~(1 << channel); 871 872 /* If no channels remain active, then put the connection on the idle 873 * list for a short while. Give it a ref to stop it going away if it 874 * becomes unbundled. 875 */ 876 if (!conn->act_chans) { 877 trace_rxrpc_client(conn, channel, rxrpc_client_to_idle); 878 conn->idle_timestamp = jiffies; 879 880 rxrpc_get_connection(conn); 881 spin_lock(&rxnet->client_conn_cache_lock); 882 list_move_tail(&conn->cache_link, &rxnet->idle_client_conns); 883 spin_unlock(&rxnet->client_conn_cache_lock); 884 885 rxrpc_set_client_reap_timer(rxnet); 886 } 887 888 out: 889 spin_unlock(&bundle->channel_lock); 890 _leave(""); 891 return; 892 } 893 894 /* 895 * Remove a connection from a bundle. 896 */ 897 static void rxrpc_unbundle_conn(struct rxrpc_connection *conn) 898 { 899 struct rxrpc_bundle *bundle = conn->bundle; 900 struct rxrpc_local *local = bundle->params.local; 901 unsigned int bindex; 902 bool need_drop = false, need_put = false; 903 int i; 904 905 _enter("C=%x", conn->debug_id); 906 907 if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK) 908 rxrpc_process_delayed_final_acks(conn, true); 909 910 spin_lock(&bundle->channel_lock); 911 bindex = conn->bundle_shift / RXRPC_MAXCALLS; 912 if (bundle->conns[bindex] == conn) { 913 _debug("clear slot %u", bindex); 914 bundle->conns[bindex] = NULL; 915 for (i = 0; i < RXRPC_MAXCALLS; i++) 916 clear_bit(conn->bundle_shift + i, &bundle->avail_chans); 917 need_drop = true; 918 } 919 spin_unlock(&bundle->channel_lock); 920 921 /* If there are no more connections, remove the bundle */ 922 if (!bundle->avail_chans) { 923 _debug("maybe unbundle"); 924 spin_lock(&local->client_bundles_lock); 925 926 for (i = 0; i < ARRAY_SIZE(bundle->conns); i++) 927 if (bundle->conns[i]) 928 break; 929 if (i == ARRAY_SIZE(bundle->conns) && !bundle->params.exclusive) { 930 _debug("erase bundle"); 931 rb_erase(&bundle->local_node, &local->client_bundles); 932 need_put = true; 933 } 934 935 spin_unlock(&local->client_bundles_lock); 936 if (need_put) 937 rxrpc_put_bundle(bundle); 938 } 939 940 if (need_drop) 941 rxrpc_put_connection(conn); 942 _leave(""); 943 } 944 945 /* 946 * Clean up a dead client connection. 947 */ 948 static void rxrpc_kill_client_conn(struct rxrpc_connection *conn) 949 { 950 struct rxrpc_local *local = conn->params.local; 951 struct rxrpc_net *rxnet = local->rxnet; 952 953 _enter("C=%x", conn->debug_id); 954 955 trace_rxrpc_client(conn, -1, rxrpc_client_cleanup); 956 atomic_dec(&rxnet->nr_client_conns); 957 958 rxrpc_put_client_connection_id(conn); 959 rxrpc_kill_connection(conn); 960 } 961 962 /* 963 * Clean up a dead client connections. 964 */ 965 void rxrpc_put_client_conn(struct rxrpc_connection *conn) 966 { 967 const void *here = __builtin_return_address(0); 968 unsigned int debug_id = conn->debug_id; 969 int n; 970 971 n = atomic_dec_return(&conn->usage); 972 trace_rxrpc_conn(debug_id, rxrpc_conn_put_client, n, here); 973 if (n <= 0) { 974 ASSERTCMP(n, >=, 0); 975 rxrpc_kill_client_conn(conn); 976 } 977 } 978 979 /* 980 * Discard expired client connections from the idle list. Each conn in the 981 * idle list has been exposed and holds an extra ref because of that. 982 * 983 * This may be called from conn setup or from a work item so cannot be 984 * considered non-reentrant. 985 */ 986 void rxrpc_discard_expired_client_conns(struct work_struct *work) 987 { 988 struct rxrpc_connection *conn; 989 struct rxrpc_net *rxnet = 990 container_of(work, struct rxrpc_net, client_conn_reaper); 991 unsigned long expiry, conn_expires_at, now; 992 unsigned int nr_conns; 993 994 _enter(""); 995 996 if (list_empty(&rxnet->idle_client_conns)) { 997 _leave(" [empty]"); 998 return; 999 } 1000 1001 /* Don't double up on the discarding */ 1002 if (!spin_trylock(&rxnet->client_conn_discard_lock)) { 1003 _leave(" [already]"); 1004 return; 1005 } 1006 1007 /* We keep an estimate of what the number of conns ought to be after 1008 * we've discarded some so that we don't overdo the discarding. 1009 */ 1010 nr_conns = atomic_read(&rxnet->nr_client_conns); 1011 1012 next: 1013 spin_lock(&rxnet->client_conn_cache_lock); 1014 1015 if (list_empty(&rxnet->idle_client_conns)) 1016 goto out; 1017 1018 conn = list_entry(rxnet->idle_client_conns.next, 1019 struct rxrpc_connection, cache_link); 1020 1021 if (!rxnet->kill_all_client_conns) { 1022 /* If the number of connections is over the reap limit, we 1023 * expedite discard by reducing the expiry timeout. We must, 1024 * however, have at least a short grace period to be able to do 1025 * final-ACK or ABORT retransmission. 1026 */ 1027 expiry = rxrpc_conn_idle_client_expiry; 1028 if (nr_conns > rxrpc_reap_client_connections) 1029 expiry = rxrpc_conn_idle_client_fast_expiry; 1030 if (conn->params.local->service_closed) 1031 expiry = rxrpc_closed_conn_expiry * HZ; 1032 1033 conn_expires_at = conn->idle_timestamp + expiry; 1034 1035 now = READ_ONCE(jiffies); 1036 if (time_after(conn_expires_at, now)) 1037 goto not_yet_expired; 1038 } 1039 1040 trace_rxrpc_client(conn, -1, rxrpc_client_discard); 1041 list_del_init(&conn->cache_link); 1042 1043 spin_unlock(&rxnet->client_conn_cache_lock); 1044 1045 rxrpc_unbundle_conn(conn); 1046 rxrpc_put_connection(conn); /* Drop the ->cache_link ref */ 1047 1048 nr_conns--; 1049 goto next; 1050 1051 not_yet_expired: 1052 /* The connection at the front of the queue hasn't yet expired, so 1053 * schedule the work item for that point if we discarded something. 1054 * 1055 * We don't worry if the work item is already scheduled - it can look 1056 * after rescheduling itself at a later time. We could cancel it, but 1057 * then things get messier. 1058 */ 1059 _debug("not yet"); 1060 if (!rxnet->kill_all_client_conns) 1061 timer_reduce(&rxnet->client_conn_reap_timer, conn_expires_at); 1062 1063 out: 1064 spin_unlock(&rxnet->client_conn_cache_lock); 1065 spin_unlock(&rxnet->client_conn_discard_lock); 1066 _leave(""); 1067 } 1068 1069 /* 1070 * Preemptively destroy all the client connection records rather than waiting 1071 * for them to time out 1072 */ 1073 void rxrpc_destroy_all_client_connections(struct rxrpc_net *rxnet) 1074 { 1075 _enter(""); 1076 1077 spin_lock(&rxnet->client_conn_cache_lock); 1078 rxnet->kill_all_client_conns = true; 1079 spin_unlock(&rxnet->client_conn_cache_lock); 1080 1081 del_timer_sync(&rxnet->client_conn_reap_timer); 1082 1083 if (!rxrpc_queue_work(&rxnet->client_conn_reaper)) 1084 _debug("destroy: queue failed"); 1085 1086 _leave(""); 1087 } 1088 1089 /* 1090 * Clean up the client connections on a local endpoint. 1091 */ 1092 void rxrpc_clean_up_local_conns(struct rxrpc_local *local) 1093 { 1094 struct rxrpc_connection *conn, *tmp; 1095 struct rxrpc_net *rxnet = local->rxnet; 1096 LIST_HEAD(graveyard); 1097 1098 _enter(""); 1099 1100 spin_lock(&rxnet->client_conn_cache_lock); 1101 1102 list_for_each_entry_safe(conn, tmp, &rxnet->idle_client_conns, 1103 cache_link) { 1104 if (conn->params.local == local) { 1105 trace_rxrpc_client(conn, -1, rxrpc_client_discard); 1106 list_move(&conn->cache_link, &graveyard); 1107 } 1108 } 1109 1110 spin_unlock(&rxnet->client_conn_cache_lock); 1111 1112 while (!list_empty(&graveyard)) { 1113 conn = list_entry(graveyard.next, 1114 struct rxrpc_connection, cache_link); 1115 list_del_init(&conn->cache_link); 1116 rxrpc_unbundle_conn(conn); 1117 rxrpc_put_connection(conn); 1118 } 1119 1120 _leave(" [culled]"); 1121 } 1122