1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* RxRPC individual remote procedure call handling 3 * 4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/slab.h> 11 #include <linux/module.h> 12 #include <linux/circ_buf.h> 13 #include <linux/spinlock_types.h> 14 #include <net/sock.h> 15 #include <net/af_rxrpc.h> 16 #include "ar-internal.h" 17 18 const char *const rxrpc_call_states[NR__RXRPC_CALL_STATES] = { 19 [RXRPC_CALL_UNINITIALISED] = "Uninit ", 20 [RXRPC_CALL_CLIENT_AWAIT_CONN] = "ClWtConn", 21 [RXRPC_CALL_CLIENT_SEND_REQUEST] = "ClSndReq", 22 [RXRPC_CALL_CLIENT_AWAIT_REPLY] = "ClAwtRpl", 23 [RXRPC_CALL_CLIENT_RECV_REPLY] = "ClRcvRpl", 24 [RXRPC_CALL_SERVER_PREALLOC] = "SvPrealc", 25 [RXRPC_CALL_SERVER_SECURING] = "SvSecure", 26 [RXRPC_CALL_SERVER_RECV_REQUEST] = "SvRcvReq", 27 [RXRPC_CALL_SERVER_ACK_REQUEST] = "SvAckReq", 28 [RXRPC_CALL_SERVER_SEND_REPLY] = "SvSndRpl", 29 [RXRPC_CALL_SERVER_AWAIT_ACK] = "SvAwtACK", 30 [RXRPC_CALL_COMPLETE] = "Complete", 31 }; 32 33 const char *const rxrpc_call_completions[NR__RXRPC_CALL_COMPLETIONS] = { 34 [RXRPC_CALL_SUCCEEDED] = "Complete", 35 [RXRPC_CALL_REMOTELY_ABORTED] = "RmtAbort", 36 [RXRPC_CALL_LOCALLY_ABORTED] = "LocAbort", 37 [RXRPC_CALL_LOCAL_ERROR] = "LocError", 38 [RXRPC_CALL_NETWORK_ERROR] = "NetError", 39 }; 40 41 struct kmem_cache *rxrpc_call_jar; 42 43 static void rxrpc_call_timer_expired(struct timer_list *t) 44 { 45 struct rxrpc_call *call = from_timer(call, t, timer); 46 47 _enter("%d", call->debug_id); 48 49 if (call->state < RXRPC_CALL_COMPLETE) { 50 trace_rxrpc_timer(call, rxrpc_timer_expired, jiffies); 51 rxrpc_queue_call(call); 52 } 53 } 54 55 static struct lock_class_key rxrpc_call_user_mutex_lock_class_key; 56 57 /* 58 * find an extant server call 59 * - called in process context with IRQs enabled 60 */ 61 struct rxrpc_call *rxrpc_find_call_by_user_ID(struct rxrpc_sock *rx, 62 unsigned long user_call_ID) 63 { 64 struct rxrpc_call *call; 65 struct rb_node *p; 66 67 _enter("%p,%lx", rx, user_call_ID); 68 69 read_lock(&rx->call_lock); 70 71 p = rx->calls.rb_node; 72 while (p) { 73 call = rb_entry(p, struct rxrpc_call, sock_node); 74 75 if (user_call_ID < call->user_call_ID) 76 p = p->rb_left; 77 else if (user_call_ID > call->user_call_ID) 78 p = p->rb_right; 79 else 80 goto found_extant_call; 81 } 82 83 read_unlock(&rx->call_lock); 84 _leave(" = NULL"); 85 return NULL; 86 87 found_extant_call: 88 rxrpc_get_call(call, rxrpc_call_got); 89 read_unlock(&rx->call_lock); 90 _leave(" = %p [%d]", call, atomic_read(&call->usage)); 91 return call; 92 } 93 94 /* 95 * allocate a new call 96 */ 97 struct rxrpc_call *rxrpc_alloc_call(struct rxrpc_sock *rx, gfp_t gfp, 98 unsigned int debug_id) 99 { 100 struct rxrpc_call *call; 101 struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk)); 102 103 call = kmem_cache_zalloc(rxrpc_call_jar, gfp); 104 if (!call) 105 return NULL; 106 107 call->rxtx_buffer = kcalloc(RXRPC_RXTX_BUFF_SIZE, 108 sizeof(struct sk_buff *), 109 gfp); 110 if (!call->rxtx_buffer) 111 goto nomem; 112 113 call->rxtx_annotations = kcalloc(RXRPC_RXTX_BUFF_SIZE, sizeof(u8), gfp); 114 if (!call->rxtx_annotations) 115 goto nomem_2; 116 117 mutex_init(&call->user_mutex); 118 119 /* Prevent lockdep reporting a deadlock false positive between the afs 120 * filesystem and sys_sendmsg() via the mmap sem. 121 */ 122 if (rx->sk.sk_kern_sock) 123 lockdep_set_class(&call->user_mutex, 124 &rxrpc_call_user_mutex_lock_class_key); 125 126 timer_setup(&call->timer, rxrpc_call_timer_expired, 0); 127 INIT_WORK(&call->processor, &rxrpc_process_call); 128 INIT_LIST_HEAD(&call->link); 129 INIT_LIST_HEAD(&call->chan_wait_link); 130 INIT_LIST_HEAD(&call->accept_link); 131 INIT_LIST_HEAD(&call->recvmsg_link); 132 INIT_LIST_HEAD(&call->sock_link); 133 init_waitqueue_head(&call->waitq); 134 spin_lock_init(&call->lock); 135 spin_lock_init(&call->notify_lock); 136 spin_lock_init(&call->input_lock); 137 rwlock_init(&call->state_lock); 138 atomic_set(&call->usage, 1); 139 call->debug_id = debug_id; 140 call->tx_total_len = -1; 141 call->next_rx_timo = 20 * HZ; 142 call->next_req_timo = 1 * HZ; 143 144 memset(&call->sock_node, 0xed, sizeof(call->sock_node)); 145 146 /* Leave space in the ring to handle a maxed-out jumbo packet */ 147 call->rx_winsize = rxrpc_rx_window_size; 148 call->tx_winsize = 16; 149 call->rx_expect_next = 1; 150 151 call->cong_cwnd = 2; 152 call->cong_ssthresh = RXRPC_RXTX_BUFF_SIZE - 1; 153 154 call->rxnet = rxnet; 155 call->rtt_avail = RXRPC_CALL_RTT_AVAIL_MASK; 156 atomic_inc(&rxnet->nr_calls); 157 return call; 158 159 nomem_2: 160 kfree(call->rxtx_buffer); 161 nomem: 162 kmem_cache_free(rxrpc_call_jar, call); 163 return NULL; 164 } 165 166 /* 167 * Allocate a new client call. 168 */ 169 static struct rxrpc_call *rxrpc_alloc_client_call(struct rxrpc_sock *rx, 170 struct sockaddr_rxrpc *srx, 171 gfp_t gfp, 172 unsigned int debug_id) 173 { 174 struct rxrpc_call *call; 175 ktime_t now; 176 177 _enter(""); 178 179 call = rxrpc_alloc_call(rx, gfp, debug_id); 180 if (!call) 181 return ERR_PTR(-ENOMEM); 182 call->state = RXRPC_CALL_CLIENT_AWAIT_CONN; 183 call->service_id = srx->srx_service; 184 call->tx_phase = true; 185 now = ktime_get_real(); 186 call->acks_latest_ts = now; 187 call->cong_tstamp = now; 188 189 _leave(" = %p", call); 190 return call; 191 } 192 193 /* 194 * Initiate the call ack/resend/expiry timer. 195 */ 196 static void rxrpc_start_call_timer(struct rxrpc_call *call) 197 { 198 unsigned long now = jiffies; 199 unsigned long j = now + MAX_JIFFY_OFFSET; 200 201 call->ack_at = j; 202 call->ack_lost_at = j; 203 call->resend_at = j; 204 call->ping_at = j; 205 call->expect_rx_by = j; 206 call->expect_req_by = j; 207 call->expect_term_by = j; 208 call->timer.expires = now; 209 } 210 211 /* 212 * Set up a call for the given parameters. 213 * - Called with the socket lock held, which it must release. 214 * - If it returns a call, the call's lock will need releasing by the caller. 215 */ 216 struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx, 217 struct rxrpc_conn_parameters *cp, 218 struct sockaddr_rxrpc *srx, 219 struct rxrpc_call_params *p, 220 gfp_t gfp, 221 unsigned int debug_id) 222 __releases(&rx->sk.sk_lock.slock) 223 __acquires(&call->user_mutex) 224 { 225 struct rxrpc_call *call, *xcall; 226 struct rxrpc_net *rxnet; 227 struct rb_node *parent, **pp; 228 const void *here = __builtin_return_address(0); 229 int ret; 230 231 _enter("%p,%lx", rx, p->user_call_ID); 232 233 call = rxrpc_alloc_client_call(rx, srx, gfp, debug_id); 234 if (IS_ERR(call)) { 235 release_sock(&rx->sk); 236 _leave(" = %ld", PTR_ERR(call)); 237 return call; 238 } 239 240 call->interruptibility = p->interruptibility; 241 call->tx_total_len = p->tx_total_len; 242 trace_rxrpc_call(call->debug_id, rxrpc_call_new_client, 243 atomic_read(&call->usage), 244 here, (const void *)p->user_call_ID); 245 246 /* We need to protect a partially set up call against the user as we 247 * will be acting outside the socket lock. 248 */ 249 mutex_lock(&call->user_mutex); 250 251 /* Publish the call, even though it is incompletely set up as yet */ 252 write_lock(&rx->call_lock); 253 254 pp = &rx->calls.rb_node; 255 parent = NULL; 256 while (*pp) { 257 parent = *pp; 258 xcall = rb_entry(parent, struct rxrpc_call, sock_node); 259 260 if (p->user_call_ID < xcall->user_call_ID) 261 pp = &(*pp)->rb_left; 262 else if (p->user_call_ID > xcall->user_call_ID) 263 pp = &(*pp)->rb_right; 264 else 265 goto error_dup_user_ID; 266 } 267 268 rcu_assign_pointer(call->socket, rx); 269 call->user_call_ID = p->user_call_ID; 270 __set_bit(RXRPC_CALL_HAS_USERID, &call->flags); 271 rxrpc_get_call(call, rxrpc_call_got_userid); 272 rb_link_node(&call->sock_node, parent, pp); 273 rb_insert_color(&call->sock_node, &rx->calls); 274 list_add(&call->sock_link, &rx->sock_calls); 275 276 write_unlock(&rx->call_lock); 277 278 rxnet = call->rxnet; 279 write_lock(&rxnet->call_lock); 280 list_add_tail(&call->link, &rxnet->calls); 281 write_unlock(&rxnet->call_lock); 282 283 /* From this point on, the call is protected by its own lock. */ 284 release_sock(&rx->sk); 285 286 /* Set up or get a connection record and set the protocol parameters, 287 * including channel number and call ID. 288 */ 289 ret = rxrpc_connect_call(rx, call, cp, srx, gfp); 290 if (ret < 0) 291 goto error_attached_to_socket; 292 293 trace_rxrpc_call(call->debug_id, rxrpc_call_connected, 294 atomic_read(&call->usage), here, NULL); 295 296 rxrpc_start_call_timer(call); 297 298 _net("CALL new %d on CONN %d", call->debug_id, call->conn->debug_id); 299 300 _leave(" = %p [new]", call); 301 return call; 302 303 /* We unexpectedly found the user ID in the list after taking 304 * the call_lock. This shouldn't happen unless the user races 305 * with itself and tries to add the same user ID twice at the 306 * same time in different threads. 307 */ 308 error_dup_user_ID: 309 write_unlock(&rx->call_lock); 310 release_sock(&rx->sk); 311 __rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR, 312 RX_CALL_DEAD, -EEXIST); 313 trace_rxrpc_call(call->debug_id, rxrpc_call_error, 314 atomic_read(&call->usage), here, ERR_PTR(-EEXIST)); 315 rxrpc_release_call(rx, call); 316 mutex_unlock(&call->user_mutex); 317 rxrpc_put_call(call, rxrpc_call_put); 318 _leave(" = -EEXIST"); 319 return ERR_PTR(-EEXIST); 320 321 /* We got an error, but the call is attached to the socket and is in 322 * need of release. However, we might now race with recvmsg() when 323 * completing the call queues it. Return 0 from sys_sendmsg() and 324 * leave the error to recvmsg() to deal with. 325 */ 326 error_attached_to_socket: 327 trace_rxrpc_call(call->debug_id, rxrpc_call_error, 328 atomic_read(&call->usage), here, ERR_PTR(ret)); 329 set_bit(RXRPC_CALL_DISCONNECTED, &call->flags); 330 __rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR, 331 RX_CALL_DEAD, ret); 332 _leave(" = c=%08x [err]", call->debug_id); 333 return call; 334 } 335 336 /* 337 * Set up an incoming call. call->conn points to the connection. 338 * This is called in BH context and isn't allowed to fail. 339 */ 340 void rxrpc_incoming_call(struct rxrpc_sock *rx, 341 struct rxrpc_call *call, 342 struct sk_buff *skb) 343 { 344 struct rxrpc_connection *conn = call->conn; 345 struct rxrpc_skb_priv *sp = rxrpc_skb(skb); 346 u32 chan; 347 348 _enter(",%d", call->conn->debug_id); 349 350 rcu_assign_pointer(call->socket, rx); 351 call->call_id = sp->hdr.callNumber; 352 call->service_id = sp->hdr.serviceId; 353 call->cid = sp->hdr.cid; 354 call->state = RXRPC_CALL_SERVER_SECURING; 355 call->cong_tstamp = skb->tstamp; 356 357 /* Set the channel for this call. We don't get channel_lock as we're 358 * only defending against the data_ready handler (which we're called 359 * from) and the RESPONSE packet parser (which is only really 360 * interested in call_counter and can cope with a disagreement with the 361 * call pointer). 362 */ 363 chan = sp->hdr.cid & RXRPC_CHANNELMASK; 364 conn->channels[chan].call_counter = call->call_id; 365 conn->channels[chan].call_id = call->call_id; 366 rcu_assign_pointer(conn->channels[chan].call, call); 367 368 spin_lock(&conn->params.peer->lock); 369 hlist_add_head_rcu(&call->error_link, &conn->params.peer->error_targets); 370 spin_unlock(&conn->params.peer->lock); 371 372 _net("CALL incoming %d on CONN %d", call->debug_id, call->conn->debug_id); 373 374 rxrpc_start_call_timer(call); 375 _leave(""); 376 } 377 378 /* 379 * Queue a call's work processor, getting a ref to pass to the work queue. 380 */ 381 bool rxrpc_queue_call(struct rxrpc_call *call) 382 { 383 const void *here = __builtin_return_address(0); 384 int n = atomic_fetch_add_unless(&call->usage, 1, 0); 385 if (n == 0) 386 return false; 387 if (rxrpc_queue_work(&call->processor)) 388 trace_rxrpc_call(call->debug_id, rxrpc_call_queued, n + 1, 389 here, NULL); 390 else 391 rxrpc_put_call(call, rxrpc_call_put_noqueue); 392 return true; 393 } 394 395 /* 396 * Queue a call's work processor, passing the callers ref to the work queue. 397 */ 398 bool __rxrpc_queue_call(struct rxrpc_call *call) 399 { 400 const void *here = __builtin_return_address(0); 401 int n = atomic_read(&call->usage); 402 ASSERTCMP(n, >=, 1); 403 if (rxrpc_queue_work(&call->processor)) 404 trace_rxrpc_call(call->debug_id, rxrpc_call_queued_ref, n, 405 here, NULL); 406 else 407 rxrpc_put_call(call, rxrpc_call_put_noqueue); 408 return true; 409 } 410 411 /* 412 * Note the re-emergence of a call. 413 */ 414 void rxrpc_see_call(struct rxrpc_call *call) 415 { 416 const void *here = __builtin_return_address(0); 417 if (call) { 418 int n = atomic_read(&call->usage); 419 420 trace_rxrpc_call(call->debug_id, rxrpc_call_seen, n, 421 here, NULL); 422 } 423 } 424 425 /* 426 * Note the addition of a ref on a call. 427 */ 428 void rxrpc_get_call(struct rxrpc_call *call, enum rxrpc_call_trace op) 429 { 430 const void *here = __builtin_return_address(0); 431 int n = atomic_inc_return(&call->usage); 432 433 trace_rxrpc_call(call->debug_id, op, n, here, NULL); 434 } 435 436 /* 437 * Clean up the RxTx skb ring. 438 */ 439 static void rxrpc_cleanup_ring(struct rxrpc_call *call) 440 { 441 int i; 442 443 for (i = 0; i < RXRPC_RXTX_BUFF_SIZE; i++) { 444 rxrpc_free_skb(call->rxtx_buffer[i], rxrpc_skb_cleaned); 445 call->rxtx_buffer[i] = NULL; 446 } 447 } 448 449 /* 450 * Detach a call from its owning socket. 451 */ 452 void rxrpc_release_call(struct rxrpc_sock *rx, struct rxrpc_call *call) 453 { 454 const void *here = __builtin_return_address(0); 455 struct rxrpc_connection *conn = call->conn; 456 bool put = false; 457 458 _enter("{%d,%d}", call->debug_id, atomic_read(&call->usage)); 459 460 trace_rxrpc_call(call->debug_id, rxrpc_call_release, 461 atomic_read(&call->usage), 462 here, (const void *)call->flags); 463 464 ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE); 465 466 spin_lock_bh(&call->lock); 467 if (test_and_set_bit(RXRPC_CALL_RELEASED, &call->flags)) 468 BUG(); 469 spin_unlock_bh(&call->lock); 470 471 del_timer_sync(&call->timer); 472 473 /* Make sure we don't get any more notifications */ 474 write_lock_bh(&rx->recvmsg_lock); 475 476 if (!list_empty(&call->recvmsg_link)) { 477 _debug("unlinking once-pending call %p { e=%lx f=%lx }", 478 call, call->events, call->flags); 479 list_del(&call->recvmsg_link); 480 put = true; 481 } 482 483 /* list_empty() must return false in rxrpc_notify_socket() */ 484 call->recvmsg_link.next = NULL; 485 call->recvmsg_link.prev = NULL; 486 487 write_unlock_bh(&rx->recvmsg_lock); 488 if (put) 489 rxrpc_put_call(call, rxrpc_call_put); 490 491 write_lock(&rx->call_lock); 492 493 if (test_and_clear_bit(RXRPC_CALL_HAS_USERID, &call->flags)) { 494 rb_erase(&call->sock_node, &rx->calls); 495 memset(&call->sock_node, 0xdd, sizeof(call->sock_node)); 496 rxrpc_put_call(call, rxrpc_call_put_userid); 497 } 498 499 list_del(&call->sock_link); 500 write_unlock(&rx->call_lock); 501 502 _debug("RELEASE CALL %p (%d CONN %p)", call, call->debug_id, conn); 503 504 if (conn && !test_bit(RXRPC_CALL_DISCONNECTED, &call->flags)) 505 rxrpc_disconnect_call(call); 506 if (call->security) 507 call->security->free_call_crypto(call); 508 509 rxrpc_cleanup_ring(call); 510 _leave(""); 511 } 512 513 /* 514 * release all the calls associated with a socket 515 */ 516 void rxrpc_release_calls_on_socket(struct rxrpc_sock *rx) 517 { 518 struct rxrpc_call *call; 519 520 _enter("%p", rx); 521 522 while (!list_empty(&rx->to_be_accepted)) { 523 call = list_entry(rx->to_be_accepted.next, 524 struct rxrpc_call, accept_link); 525 list_del(&call->accept_link); 526 rxrpc_abort_call("SKR", call, 0, RX_CALL_DEAD, -ECONNRESET); 527 rxrpc_put_call(call, rxrpc_call_put); 528 } 529 530 while (!list_empty(&rx->sock_calls)) { 531 call = list_entry(rx->sock_calls.next, 532 struct rxrpc_call, sock_link); 533 rxrpc_get_call(call, rxrpc_call_got); 534 rxrpc_abort_call("SKT", call, 0, RX_CALL_DEAD, -ECONNRESET); 535 rxrpc_send_abort_packet(call); 536 rxrpc_release_call(rx, call); 537 rxrpc_put_call(call, rxrpc_call_put); 538 } 539 540 _leave(""); 541 } 542 543 /* 544 * release a call 545 */ 546 void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op) 547 { 548 struct rxrpc_net *rxnet = call->rxnet; 549 const void *here = __builtin_return_address(0); 550 unsigned int debug_id = call->debug_id; 551 int n; 552 553 ASSERT(call != NULL); 554 555 n = atomic_dec_return(&call->usage); 556 trace_rxrpc_call(debug_id, op, n, here, NULL); 557 ASSERTCMP(n, >=, 0); 558 if (n == 0) { 559 _debug("call %d dead", call->debug_id); 560 ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE); 561 562 if (!list_empty(&call->link)) { 563 write_lock(&rxnet->call_lock); 564 list_del_init(&call->link); 565 write_unlock(&rxnet->call_lock); 566 } 567 568 rxrpc_cleanup_call(call); 569 } 570 } 571 572 /* 573 * Final call destruction - but must be done in process context. 574 */ 575 static void rxrpc_destroy_call(struct work_struct *work) 576 { 577 struct rxrpc_call *call = container_of(work, struct rxrpc_call, processor); 578 struct rxrpc_net *rxnet = call->rxnet; 579 580 rxrpc_put_connection(call->conn); 581 rxrpc_put_peer(call->peer); 582 kfree(call->rxtx_buffer); 583 kfree(call->rxtx_annotations); 584 kmem_cache_free(rxrpc_call_jar, call); 585 if (atomic_dec_and_test(&rxnet->nr_calls)) 586 wake_up_var(&rxnet->nr_calls); 587 } 588 589 /* 590 * Final call destruction under RCU. 591 */ 592 static void rxrpc_rcu_destroy_call(struct rcu_head *rcu) 593 { 594 struct rxrpc_call *call = container_of(rcu, struct rxrpc_call, rcu); 595 596 if (in_softirq()) { 597 INIT_WORK(&call->processor, rxrpc_destroy_call); 598 if (!rxrpc_queue_work(&call->processor)) 599 BUG(); 600 } else { 601 rxrpc_destroy_call(&call->processor); 602 } 603 } 604 605 /* 606 * clean up a call 607 */ 608 void rxrpc_cleanup_call(struct rxrpc_call *call) 609 { 610 _net("DESTROY CALL %d", call->debug_id); 611 612 memset(&call->sock_node, 0xcd, sizeof(call->sock_node)); 613 614 del_timer_sync(&call->timer); 615 616 ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE); 617 ASSERT(test_bit(RXRPC_CALL_RELEASED, &call->flags)); 618 619 rxrpc_cleanup_ring(call); 620 rxrpc_free_skb(call->tx_pending, rxrpc_skb_cleaned); 621 622 call_rcu(&call->rcu, rxrpc_rcu_destroy_call); 623 } 624 625 /* 626 * Make sure that all calls are gone from a network namespace. To reach this 627 * point, any open UDP sockets in that namespace must have been closed, so any 628 * outstanding calls cannot be doing I/O. 629 */ 630 void rxrpc_destroy_all_calls(struct rxrpc_net *rxnet) 631 { 632 struct rxrpc_call *call; 633 634 _enter(""); 635 636 if (!list_empty(&rxnet->calls)) { 637 write_lock(&rxnet->call_lock); 638 639 while (!list_empty(&rxnet->calls)) { 640 call = list_entry(rxnet->calls.next, 641 struct rxrpc_call, link); 642 _debug("Zapping call %p", call); 643 644 rxrpc_see_call(call); 645 list_del_init(&call->link); 646 647 pr_err("Call %p still in use (%d,%s,%lx,%lx)!\n", 648 call, atomic_read(&call->usage), 649 rxrpc_call_states[call->state], 650 call->flags, call->events); 651 652 write_unlock(&rxnet->call_lock); 653 cond_resched(); 654 write_lock(&rxnet->call_lock); 655 } 656 657 write_unlock(&rxnet->call_lock); 658 } 659 660 atomic_dec(&rxnet->nr_calls); 661 wait_var_event(&rxnet->nr_calls, !atomic_read(&rxnet->nr_calls)); 662 } 663