net/rxrpc/call_accept.c

   1 /* incoming call handling
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/module.h>
  15 #include <linux/net.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/errqueue.h>
  18 #include <linux/udp.h>
  19 #include <linux/in.h>
  20 #include <linux/in6.h>
  21 #include <linux/icmp.h>
  22 #include <linux/gfp.h>
  23 #include <linux/circ_buf.h>
  24 #include <net/sock.h>
  25 #include <net/af_rxrpc.h>
  26 #include <net/ip.h>
  27 #include "ar-internal.h"
  28
  29 /*
  30  * Preallocate a single service call, connection and peer and, if possible,
  31  * give them a user ID and attach the user's side of the ID to them.
  32  */
  33 static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx,
  34                                       struct rxrpc_backlog *b,
  35                                       rxrpc_notify_rx_t notify_rx,
  36                                       rxrpc_user_attach_call_t user_attach_call,
  37                                       unsigned long user_call_ID, gfp_t gfp,
  38                                       unsigned int debug_id)
  39 {
  40         const void *here = __builtin_return_address(0);
  41         struct rxrpc_call *call;
  42         struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
  43         int max, tmp;
  44         unsigned int size = RXRPC_BACKLOG_MAX;
  45         unsigned int head, tail, call_head, call_tail;
  46
  47         max = rx->sk.sk_max_ack_backlog;
  48         tmp = rx->sk.sk_ack_backlog;
  49         if (tmp >= max) {
  50                 _leave(" = -ENOBUFS [full %u]", max);
  51                 return -ENOBUFS;
  52         }
  53         max -= tmp;
  54
  55         /* We don't need more conns and peers than we have calls, but on the
  56          * other hand, we shouldn't ever use more peers than conns or conns
  57          * than calls.
  58          */
  59         call_head = b->call_backlog_head;
  60         call_tail = READ_ONCE(b->call_backlog_tail);
  61         tmp = CIRC_CNT(call_head, call_tail, size);
  62         if (tmp >= max) {
  63                 _leave(" = -ENOBUFS [enough %u]", tmp);
  64                 return -ENOBUFS;
  65         }
  66         max = tmp + 1;
  67
  68         head = b->peer_backlog_head;
  69         tail = READ_ONCE(b->peer_backlog_tail);
  70         if (CIRC_CNT(head, tail, size) < max) {
  71                 struct rxrpc_peer *peer = rxrpc_alloc_peer(rx->local, gfp);
  72                 if (!peer)
  73                         return -ENOMEM;
  74                 b->peer_backlog[head] = peer;
  75                 smp_store_release(&b->peer_backlog_head,
  76                                   (head + 1) & (size - 1));
  77         }
  78
  79         head = b->conn_backlog_head;
  80         tail = READ_ONCE(b->conn_backlog_tail);
  81         if (CIRC_CNT(head, tail, size) < max) {
  82                 struct rxrpc_connection *conn;
  83
  84                 conn = rxrpc_prealloc_service_connection(rxnet, gfp);
  85                 if (!conn)
  86                         return -ENOMEM;
  87                 b->conn_backlog[head] = conn;
  88                 smp_store_release(&b->conn_backlog_head,
  89                                   (head + 1) & (size - 1));
  90
  91                 trace_rxrpc_conn(conn, rxrpc_conn_new_service,
  92                                  atomic_read(&conn->usage), here);
  93         }
  94
  95         /* Now it gets complicated, because calls get registered with the
  96          * socket here, particularly if a user ID is preassigned by the user.
  97          */
  98         call = rxrpc_alloc_call(rx, gfp, debug_id);
  99         if (!call)
 100                 return -ENOMEM;
 101         call->flags |= (1 << RXRPC_CALL_IS_SERVICE);
 102         call->state = RXRPC_CALL_SERVER_PREALLOC;
 103
 104         trace_rxrpc_call(call, rxrpc_call_new_service,
 105                          atomic_read(&call->usage),
 106                          here, (const void *)user_call_ID);
 107
 108         write_lock(&rx->call_lock);
 109         if (user_attach_call) {
 110                 struct rxrpc_call *xcall;
 111                 struct rb_node *parent, **pp;
 112
 113                 /* Check the user ID isn't already in use */
 114                 pp = &rx->calls.rb_node;
 115                 parent = NULL;
 116                 while (*pp) {
 117                         parent = *pp;
 118                         xcall = rb_entry(parent, struct rxrpc_call, sock_node);
 119                         if (user_call_ID < xcall->user_call_ID)
 120                                 pp = &(*pp)->rb_left;
 121                         else if (user_call_ID > xcall->user_call_ID)
 122                                 pp = &(*pp)->rb_right;
 123                         else
 124                                 goto id_in_use;
 125                 }
 126
 127                 call->user_call_ID = user_call_ID;
 128                 call->notify_rx = notify_rx;
 129                 rxrpc_get_call(call, rxrpc_call_got_kernel);
 130                 user_attach_call(call, user_call_ID);
 131                 rxrpc_get_call(call, rxrpc_call_got_userid);
 132                 rb_link_node(&call->sock_node, parent, pp);
 133                 rb_insert_color(&call->sock_node, &rx->calls);
 134                 set_bit(RXRPC_CALL_HAS_USERID, &call->flags);
 135         }
 136
 137         list_add(&call->sock_link, &rx->sock_calls);
 138
 139         write_unlock(&rx->call_lock);
 140
 141         rxnet = call->rxnet;
 142         write_lock(&rxnet->call_lock);
 143         list_add_tail(&call->link, &rxnet->calls);
 144         write_unlock(&rxnet->call_lock);
 145
 146         b->call_backlog[call_head] = call;
 147         smp_store_release(&b->call_backlog_head, (call_head + 1) & (size - 1));
 148         _leave(" = 0 [%d -> %lx]", call->debug_id, user_call_ID);
 149         return 0;
 150
 151 id_in_use:
 152         write_unlock(&rx->call_lock);
 153         rxrpc_cleanup_call(call);
 154         _leave(" = -EBADSLT");
 155         return -EBADSLT;
 156 }
 157
 158 /*
 159  * Preallocate sufficient service connections, calls and peers to cover the
 160  * entire backlog of a socket.  When a new call comes in, if we don't have
 161  * sufficient of each available, the call gets rejected as busy or ignored.
 162  *
 163  * The backlog is replenished when a connection is accepted or rejected.
 164  */
 165 int rxrpc_service_prealloc(struct rxrpc_sock *rx, gfp_t gfp)
 166 {
 167         struct rxrpc_backlog *b = rx->backlog;
 168
 169         if (!b) {
 170                 b = kzalloc(sizeof(struct rxrpc_backlog), gfp);
 171                 if (!b)
 172                         return -ENOMEM;
 173                 rx->backlog = b;
 174         }
 175
 176         if (rx->discard_new_call)
 177                 return 0;
 178
 179         while (rxrpc_service_prealloc_one(rx, b, NULL, NULL, 0, gfp,
 180                                           atomic_inc_return(&rxrpc_debug_id)) == 0)
 181                 ;
 182
 183         return 0;
 184 }
 185
 186 /*
 187  * Discard the preallocation on a service.
 188  */
 189 void rxrpc_discard_prealloc(struct rxrpc_sock *rx)
 190 {
 191         struct rxrpc_backlog *b = rx->backlog;
 192         struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
 193         unsigned int size = RXRPC_BACKLOG_MAX, head, tail;
 194
 195         if (!b)
 196                 return;
 197         rx->backlog = NULL;
 198
 199         /* Make sure that there aren't any incoming calls in progress before we
 200          * clear the preallocation buffers.
 201          */
 202         spin_lock_bh(&rx->incoming_lock);
 203         spin_unlock_bh(&rx->incoming_lock);
 204
 205         head = b->peer_backlog_head;
 206         tail = b->peer_backlog_tail;
 207         while (CIRC_CNT(head, tail, size) > 0) {
 208                 struct rxrpc_peer *peer = b->peer_backlog[tail];
 209                 kfree(peer);
 210                 tail = (tail + 1) & (size - 1);
 211         }
 212
 213         head = b->conn_backlog_head;
 214         tail = b->conn_backlog_tail;
 215         while (CIRC_CNT(head, tail, size) > 0) {
 216                 struct rxrpc_connection *conn = b->conn_backlog[tail];
 217                 write_lock(&rxnet->conn_lock);
 218                 list_del(&conn->link);
 219                 list_del(&conn->proc_link);
 220                 write_unlock(&rxnet->conn_lock);
 221                 kfree(conn);
 222                 if (atomic_dec_and_test(&rxnet->nr_conns))
 223                         wake_up_var(&rxnet->nr_conns);
 224                 tail = (tail + 1) & (size - 1);
 225         }
 226
 227         head = b->call_backlog_head;
 228         tail = b->call_backlog_tail;
 229         while (CIRC_CNT(head, tail, size) > 0) {
 230                 struct rxrpc_call *call = b->call_backlog[tail];
 231                 rcu_assign_pointer(call->socket, rx);
 232                 if (rx->discard_new_call) {
 233                         _debug("discard %lx", call->user_call_ID);
 234                         rx->discard_new_call(call, call->user_call_ID);
 235                         rxrpc_put_call(call, rxrpc_call_put_kernel);
 236                 }
 237                 rxrpc_call_completed(call);
 238                 rxrpc_release_call(rx, call);
 239                 rxrpc_put_call(call, rxrpc_call_put);
 240                 tail = (tail + 1) & (size - 1);
 241         }
 242
 243         kfree(b);
 244 }
 245
 246 /*
 247  * Allocate a new incoming call from the prealloc pool, along with a connection
 248  * and a peer as necessary.
 249  */
 250 static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
 251                                                     struct rxrpc_local *local,
 252                                                     struct rxrpc_peer *peer,
 253                                                     struct rxrpc_connection *conn,
 254                                                     struct sk_buff *skb)
 255 {
 256         struct rxrpc_backlog *b = rx->backlog;
 257         struct rxrpc_call *call;
 258         unsigned short call_head, conn_head, peer_head;
 259         unsigned short call_tail, conn_tail, peer_tail;
 260         unsigned short call_count, conn_count;
 261
 262         /* #calls >= #conns >= #peers must hold true. */
 263         call_head = smp_load_acquire(&b->call_backlog_head);
 264         call_tail = b->call_backlog_tail;
 265         call_count = CIRC_CNT(call_head, call_tail, RXRPC_BACKLOG_MAX);
 266         conn_head = smp_load_acquire(&b->conn_backlog_head);
 267         conn_tail = b->conn_backlog_tail;
 268         conn_count = CIRC_CNT(conn_head, conn_tail, RXRPC_BACKLOG_MAX);
 269         ASSERTCMP(conn_count, >=, call_count);
 270         peer_head = smp_load_acquire(&b->peer_backlog_head);
 271         peer_tail = b->peer_backlog_tail;
 272         ASSERTCMP(CIRC_CNT(peer_head, peer_tail, RXRPC_BACKLOG_MAX), >=,
 273                   conn_count);
 274
 275         if (call_count == 0)
 276                 return NULL;
 277
 278         if (!conn) {
 279                 if (peer && !rxrpc_get_peer_maybe(peer))
 280                         peer = NULL;
 281                 if (!peer) {
 282                         peer = b->peer_backlog[peer_tail];
 283                         if (rxrpc_extract_addr_from_skb(&peer->srx, skb) < 0)
 284                                 return NULL;
 285                         b->peer_backlog[peer_tail] = NULL;
 286                         smp_store_release(&b->peer_backlog_tail,
 287                                           (peer_tail + 1) &
 288                                           (RXRPC_BACKLOG_MAX - 1));
 289
 290                         rxrpc_new_incoming_peer(rx, local, peer);
 291                 }
 292
 293                 /* Now allocate and set up the connection */
 294                 conn = b->conn_backlog[conn_tail];
 295                 b->conn_backlog[conn_tail] = NULL;
 296                 smp_store_release(&b->conn_backlog_tail,
 297                                   (conn_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
 298                 conn->params.local = rxrpc_get_local(local);
 299                 conn->params.peer = peer;
 300                 rxrpc_see_connection(conn);
 301                 rxrpc_new_incoming_connection(rx, conn, skb);
 302         } else {
 303                 rxrpc_get_connection(conn);
 304         }
 305
 306         /* And now we can allocate and set up a new call */
 307         call = b->call_backlog[call_tail];
 308         b->call_backlog[call_tail] = NULL;
 309         smp_store_release(&b->call_backlog_tail,
 310                           (call_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
 311
 312         rxrpc_see_call(call);
 313         call->conn = conn;
 314         call->peer = rxrpc_get_peer(conn->params.peer);
 315         call->cong_cwnd = call->peer->cong_cwnd;
 316         return call;
 317 }
 318
 319 /*
 320  * Set up a new incoming call.  Called in BH context with the RCU read lock
 321  * held.
 322  *
 323  * If this is for a kernel service, when we allocate the call, it will have
 324  * three refs on it: (1) the kernel service, (2) the user_call_ID tree, (3) the
 325  * retainer ref obtained from the backlog buffer.  Prealloc calls for userspace
 326  * services only have the ref from the backlog buffer.  We want to pass this
 327  * ref to non-BH context to dispose of.
 328  *
 329  * If we want to report an error, we mark the skb with the packet type and
 330  * abort code and return NULL.
 331  *
 332  * The call is returned with the user access mutex held.
 333  */
 334 struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
 335                                            struct rxrpc_sock *rx,
 336                                            struct sk_buff *skb)
 337 {
 338         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 339         struct rxrpc_connection *conn;
 340         struct rxrpc_peer *peer = NULL;
 341         struct rxrpc_call *call;
 342
 343         _enter("");
 344
 345         spin_lock(&rx->incoming_lock);
 346         if (rx->sk.sk_state == RXRPC_SERVER_LISTEN_DISABLED ||
 347             rx->sk.sk_state == RXRPC_CLOSE) {
 348                 trace_rxrpc_abort(0, "CLS", sp->hdr.cid, sp->hdr.callNumber,
 349                                   sp->hdr.seq, RX_INVALID_OPERATION, ESHUTDOWN);
 350                 skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
 351                 skb->priority = RX_INVALID_OPERATION;
 352                 _leave(" = NULL [close]");
 353                 call = NULL;
 354                 goto out;
 355         }
 356
 357         /* The peer, connection and call may all have sprung into existence due
 358          * to a duplicate packet being handled on another CPU in parallel, so
 359          * we have to recheck the routing.  However, we're now holding
 360          * rx->incoming_lock, so the values should remain stable.
 361          */
 362         conn = rxrpc_find_connection_rcu(local, skb, &peer);
 363
 364         call = rxrpc_alloc_incoming_call(rx, local, peer, conn, skb);
 365         if (!call) {
 366                 skb->mark = RXRPC_SKB_MARK_REJECT_BUSY;
 367                 _leave(" = NULL [busy]");
 368                 call = NULL;
 369                 goto out;
 370         }
 371
 372         trace_rxrpc_receive(call, rxrpc_receive_incoming,
 373                             sp->hdr.serial, sp->hdr.seq);
 374
 375         /* Lock the call to prevent rxrpc_kernel_send/recv_data() and
 376          * sendmsg()/recvmsg() inconveniently stealing the mutex once the
 377          * notification is generated.
 378          *
 379          * The BUG should never happen because the kernel should be well
 380          * behaved enough not to access the call before the first notification
 381          * event and userspace is prevented from doing so until the state is
 382          * appropriate.
 383          */
 384         if (!mutex_trylock(&call->user_mutex))
 385                 BUG();
 386
 387         /* Make the call live. */
 388         rxrpc_incoming_call(rx, call, skb);
 389         conn = call->conn;
 390
 391         if (rx->notify_new_call)
 392                 rx->notify_new_call(&rx->sk, call, call->user_call_ID);
 393         else
 394                 sk_acceptq_added(&rx->sk);
 395
 396         spin_lock(&conn->state_lock);
 397         switch (conn->state) {
 398         case RXRPC_CONN_SERVICE_UNSECURED:
 399                 conn->state = RXRPC_CONN_SERVICE_CHALLENGING;
 400                 set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events);
 401                 rxrpc_queue_conn(call->conn);
 402                 break;
 403
 404         case RXRPC_CONN_SERVICE:
 405                 write_lock(&call->state_lock);
 406                 if (call->state < RXRPC_CALL_COMPLETE) {
 407                         if (rx->discard_new_call)
 408                                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 409                         else
 410                                 call->state = RXRPC_CALL_SERVER_ACCEPTING;
 411                 }
 412                 write_unlock(&call->state_lock);
 413                 break;
 414
 415         case RXRPC_CONN_REMOTELY_ABORTED:
 416                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 417                                           conn->abort_code, conn->error);
 418                 break;
 419         case RXRPC_CONN_LOCALLY_ABORTED:
 420                 rxrpc_abort_call("CON", call, sp->hdr.seq,
 421                                  conn->abort_code, conn->error);
 422                 break;
 423         default:
 424                 BUG();
 425         }
 426         spin_unlock(&conn->state_lock);
 427
 428         if (call->state == RXRPC_CALL_SERVER_ACCEPTING)
 429                 rxrpc_notify_socket(call);
 430
 431         /* We have to discard the prealloc queue's ref here and rely on a
 432          * combination of the RCU read lock and refs held either by the socket
 433          * (recvmsg queue, to-be-accepted queue or user ID tree) or the kernel
 434          * service to prevent the call from being deallocated too early.
 435          */
 436         rxrpc_put_call(call, rxrpc_call_put);
 437
 438         _leave(" = %p{%d}", call, call->debug_id);
 439 out:
 440         spin_unlock(&rx->incoming_lock);
 441         return call;
 442 }
 443
 444 /*
 445  * handle acceptance of a call by userspace
 446  * - assign the user call ID to the call at the front of the queue
 447  * - called with the socket locked.
 448  */
 449 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 450                                      unsigned long user_call_ID,
 451                                      rxrpc_notify_rx_t notify_rx)
 452         __releases(&rx->sk.sk_lock.slock)
 453         __acquires(call->user_mutex)
 454 {
 455         struct rxrpc_call *call;
 456         struct rb_node *parent, **pp;
 457         int ret;
 458
 459         _enter(",%lx", user_call_ID);
 460
 461         ASSERT(!irqs_disabled());
 462
 463         write_lock(&rx->call_lock);
 464
 465         if (list_empty(&rx->to_be_accepted)) {
 466                 write_unlock(&rx->call_lock);
 467                 release_sock(&rx->sk);
 468                 kleave(" = -ENODATA [empty]");
 469                 return ERR_PTR(-ENODATA);
 470         }
 471
 472         /* check the user ID isn't already in use */
 473         pp = &rx->calls.rb_node;
 474         parent = NULL;
 475         while (*pp) {
 476                 parent = *pp;
 477                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 478
 479                 if (user_call_ID < call->user_call_ID)
 480                         pp = &(*pp)->rb_left;
 481                 else if (user_call_ID > call->user_call_ID)
 482                         pp = &(*pp)->rb_right;
 483                 else
 484                         goto id_in_use;
 485         }
 486
 487         /* Dequeue the first call and check it's still valid.  We gain
 488          * responsibility for the queue's reference.
 489          */
 490         call = list_entry(rx->to_be_accepted.next,
 491                           struct rxrpc_call, accept_link);
 492         write_unlock(&rx->call_lock);
 493
 494         /* We need to gain the mutex from the interrupt handler without
 495          * upsetting lockdep, so we have to release it there and take it here.
 496          * We are, however, still holding the socket lock, so other accepts
 497          * must wait for us and no one can add the user ID behind our backs.
 498          */
 499         if (mutex_lock_interruptible(&call->user_mutex) < 0) {
 500                 release_sock(&rx->sk);
 501                 kleave(" = -ERESTARTSYS");
 502                 return ERR_PTR(-ERESTARTSYS);
 503         }
 504
 505         write_lock(&rx->call_lock);
 506         list_del_init(&call->accept_link);
 507         sk_acceptq_removed(&rx->sk);
 508         rxrpc_see_call(call);
 509
 510         /* Find the user ID insertion point. */
 511         pp = &rx->calls.rb_node;
 512         parent = NULL;
 513         while (*pp) {
 514                 parent = *pp;
 515                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 516
 517                 if (user_call_ID < call->user_call_ID)
 518                         pp = &(*pp)->rb_left;
 519                 else if (user_call_ID > call->user_call_ID)
 520                         pp = &(*pp)->rb_right;
 521                 else
 522                         BUG();
 523         }
 524
 525         write_lock_bh(&call->state_lock);
 526         switch (call->state) {
 527         case RXRPC_CALL_SERVER_ACCEPTING:
 528                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 529                 break;
 530         case RXRPC_CALL_COMPLETE:
 531                 ret = call->error;
 532                 goto out_release;
 533         default:
 534                 BUG();
 535         }
 536
 537         /* formalise the acceptance */
 538         call->notify_rx = notify_rx;
 539         call->user_call_ID = user_call_ID;
 540         rxrpc_get_call(call, rxrpc_call_got_userid);
 541         rb_link_node(&call->sock_node, parent, pp);
 542         rb_insert_color(&call->sock_node, &rx->calls);
 543         if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
 544                 BUG();
 545
 546         write_unlock_bh(&call->state_lock);
 547         write_unlock(&rx->call_lock);
 548         rxrpc_notify_socket(call);
 549         rxrpc_service_prealloc(rx, GFP_KERNEL);
 550         release_sock(&rx->sk);
 551         _leave(" = %p{%d}", call, call->debug_id);
 552         return call;
 553
 554 out_release:
 555         _debug("release %p", call);
 556         write_unlock_bh(&call->state_lock);
 557         write_unlock(&rx->call_lock);
 558         rxrpc_release_call(rx, call);
 559         rxrpc_put_call(call, rxrpc_call_put);
 560         goto out;
 561
 562 id_in_use:
 563         ret = -EBADSLT;
 564         write_unlock(&rx->call_lock);
 565 out:
 566         rxrpc_service_prealloc(rx, GFP_KERNEL);
 567         release_sock(&rx->sk);
 568         _leave(" = %d", ret);
 569         return ERR_PTR(ret);
 570 }
 571
 572 /*
 573  * Handle rejection of a call by userspace
 574  * - reject the call at the front of the queue
 575  */
 576 int rxrpc_reject_call(struct rxrpc_sock *rx)
 577 {
 578         struct rxrpc_call *call;
 579         bool abort = false;
 580         int ret;
 581
 582         _enter("");
 583
 584         ASSERT(!irqs_disabled());
 585
 586         write_lock(&rx->call_lock);
 587
 588         if (list_empty(&rx->to_be_accepted)) {
 589                 write_unlock(&rx->call_lock);
 590                 return -ENODATA;
 591         }
 592
 593         /* Dequeue the first call and check it's still valid.  We gain
 594          * responsibility for the queue's reference.
 595          */
 596         call = list_entry(rx->to_be_accepted.next,
 597                           struct rxrpc_call, accept_link);
 598         list_del_init(&call->accept_link);
 599         sk_acceptq_removed(&rx->sk);
 600         rxrpc_see_call(call);
 601
 602         write_lock_bh(&call->state_lock);
 603         switch (call->state) {
 604         case RXRPC_CALL_SERVER_ACCEPTING:
 605                 __rxrpc_abort_call("REJ", call, 1, RX_USER_ABORT, -ECONNABORTED);
 606                 abort = true;
 607                 /* fall through */
 608         case RXRPC_CALL_COMPLETE:
 609                 ret = call->error;
 610                 goto out_discard;
 611         default:
 612                 BUG();
 613         }
 614
 615 out_discard:
 616         write_unlock_bh(&call->state_lock);
 617         write_unlock(&rx->call_lock);
 618         if (abort) {
 619                 rxrpc_send_abort_packet(call);
 620                 rxrpc_release_call(rx, call);
 621                 rxrpc_put_call(call, rxrpc_call_put);
 622         }
 623         rxrpc_service_prealloc(rx, GFP_KERNEL);
 624         _leave(" = %d", ret);
 625         return ret;
 626 }
 627
 628 /*
 629  * rxrpc_kernel_charge_accept - Charge up socket with preallocated calls
 630  * @sock: The socket on which to preallocate
 631  * @notify_rx: Event notification function for the call
 632  * @user_attach_call: Func to attach call to user_call_ID
 633  * @user_call_ID: The tag to attach to the preallocated call
 634  * @gfp: The allocation conditions.
 635  * @debug_id: The tracing debug ID.
 636  *
 637  * Charge up the socket with preallocated calls, each with a user ID.  A
 638  * function should be provided to effect the attachment from the user's side.
 639  * The user is given a ref to hold on the call.
 640  *
 641  * Note that the call may be come connected before this function returns.
 642  */
 643 int rxrpc_kernel_charge_accept(struct socket *sock,
 644                                rxrpc_notify_rx_t notify_rx,
 645                                rxrpc_user_attach_call_t user_attach_call,
 646                                unsigned long user_call_ID, gfp_t gfp,
 647                                unsigned int debug_id)
 648 {
 649         struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
 650         struct rxrpc_backlog *b = rx->backlog;
 651
 652         if (sock->sk->sk_state == RXRPC_CLOSE)
 653                 return -ESHUTDOWN;
 654
 655         return rxrpc_service_prealloc_one(rx, b, notify_rx,
 656                                           user_attach_call, user_call_ID,
 657                                           gfp, debug_id);
 658 }
 659 EXPORT_SYMBOL(rxrpc_kernel_charge_accept);