net/rxrpc/call_accept.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* incoming 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/module.h>
  11 #include <linux/net.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/errqueue.h>
  14 #include <linux/udp.h>
  15 #include <linux/in.h>
  16 #include <linux/in6.h>
  17 #include <linux/icmp.h>
  18 #include <linux/gfp.h>
  19 #include <linux/circ_buf.h>
  20 #include <net/sock.h>
  21 #include <net/af_rxrpc.h>
  22 #include <net/ip.h>
  23 #include "ar-internal.h"
  24
  25 /*
  26  * Preallocate a single service call, connection and peer and, if possible,
  27  * give them a user ID and attach the user's side of the ID to them.
  28  */
  29 static int rxrpc_service_prealloc_one(struct rxrpc_sock *rx,
  30                                       struct rxrpc_backlog *b,
  31                                       rxrpc_notify_rx_t notify_rx,
  32                                       rxrpc_user_attach_call_t user_attach_call,
  33                                       unsigned long user_call_ID, gfp_t gfp,
  34                                       unsigned int debug_id)
  35 {
  36         const void *here = __builtin_return_address(0);
  37         struct rxrpc_call *call;
  38         struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
  39         int max, tmp;
  40         unsigned int size = RXRPC_BACKLOG_MAX;
  41         unsigned int head, tail, call_head, call_tail;
  42
  43         max = rx->sk.sk_max_ack_backlog;
  44         tmp = rx->sk.sk_ack_backlog;
  45         if (tmp >= max) {
  46                 _leave(" = -ENOBUFS [full %u]", max);
  47                 return -ENOBUFS;
  48         }
  49         max -= tmp;
  50
  51         /* We don't need more conns and peers than we have calls, but on the
  52          * other hand, we shouldn't ever use more peers than conns or conns
  53          * than calls.
  54          */
  55         call_head = b->call_backlog_head;
  56         call_tail = READ_ONCE(b->call_backlog_tail);
  57         tmp = CIRC_CNT(call_head, call_tail, size);
  58         if (tmp >= max) {
  59                 _leave(" = -ENOBUFS [enough %u]", tmp);
  60                 return -ENOBUFS;
  61         }
  62         max = tmp + 1;
  63
  64         head = b->peer_backlog_head;
  65         tail = READ_ONCE(b->peer_backlog_tail);
  66         if (CIRC_CNT(head, tail, size) < max) {
  67                 struct rxrpc_peer *peer = rxrpc_alloc_peer(rx->local, gfp);
  68                 if (!peer)
  69                         return -ENOMEM;
  70                 b->peer_backlog[head] = peer;
  71                 smp_store_release(&b->peer_backlog_head,
  72                                   (head + 1) & (size - 1));
  73         }
  74
  75         head = b->conn_backlog_head;
  76         tail = READ_ONCE(b->conn_backlog_tail);
  77         if (CIRC_CNT(head, tail, size) < max) {
  78                 struct rxrpc_connection *conn;
  79
  80                 conn = rxrpc_prealloc_service_connection(rxnet, gfp);
  81                 if (!conn)
  82                         return -ENOMEM;
  83                 b->conn_backlog[head] = conn;
  84                 smp_store_release(&b->conn_backlog_head,
  85                                   (head + 1) & (size - 1));
  86
  87                 trace_rxrpc_conn(conn, rxrpc_conn_new_service,
  88                                  atomic_read(&conn->usage), here);
  89         }
  90
  91         /* Now it gets complicated, because calls get registered with the
  92          * socket here, particularly if a user ID is preassigned by the user.
  93          */
  94         call = rxrpc_alloc_call(rx, gfp, debug_id);
  95         if (!call)
  96                 return -ENOMEM;
  97         call->flags |= (1 << RXRPC_CALL_IS_SERVICE);
  98         call->state = RXRPC_CALL_SERVER_PREALLOC;
  99
 100         trace_rxrpc_call(call, rxrpc_call_new_service,
 101                          atomic_read(&call->usage),
 102                          here, (const void *)user_call_ID);
 103
 104         write_lock(&rx->call_lock);
 105         if (user_attach_call) {
 106                 struct rxrpc_call *xcall;
 107                 struct rb_node *parent, **pp;
 108
 109                 /* Check the user ID isn't already in use */
 110                 pp = &rx->calls.rb_node;
 111                 parent = NULL;
 112                 while (*pp) {
 113                         parent = *pp;
 114                         xcall = rb_entry(parent, struct rxrpc_call, sock_node);
 115                         if (user_call_ID < xcall->user_call_ID)
 116                                 pp = &(*pp)->rb_left;
 117                         else if (user_call_ID > xcall->user_call_ID)
 118                                 pp = &(*pp)->rb_right;
 119                         else
 120                                 goto id_in_use;
 121                 }
 122
 123                 call->user_call_ID = user_call_ID;
 124                 call->notify_rx = notify_rx;
 125                 rxrpc_get_call(call, rxrpc_call_got_kernel);
 126                 user_attach_call(call, user_call_ID);
 127                 rxrpc_get_call(call, rxrpc_call_got_userid);
 128                 rb_link_node(&call->sock_node, parent, pp);
 129                 rb_insert_color(&call->sock_node, &rx->calls);
 130                 set_bit(RXRPC_CALL_HAS_USERID, &call->flags);
 131         }
 132
 133         list_add(&call->sock_link, &rx->sock_calls);
 134
 135         write_unlock(&rx->call_lock);
 136
 137         rxnet = call->rxnet;
 138         write_lock(&rxnet->call_lock);
 139         list_add_tail(&call->link, &rxnet->calls);
 140         write_unlock(&rxnet->call_lock);
 141
 142         b->call_backlog[call_head] = call;
 143         smp_store_release(&b->call_backlog_head, (call_head + 1) & (size - 1));
 144         _leave(" = 0 [%d -> %lx]", call->debug_id, user_call_ID);
 145         return 0;
 146
 147 id_in_use:
 148         write_unlock(&rx->call_lock);
 149         rxrpc_cleanup_call(call);
 150         _leave(" = -EBADSLT");
 151         return -EBADSLT;
 152 }
 153
 154 /*
 155  * Preallocate sufficient service connections, calls and peers to cover the
 156  * entire backlog of a socket.  When a new call comes in, if we don't have
 157  * sufficient of each available, the call gets rejected as busy or ignored.
 158  *
 159  * The backlog is replenished when a connection is accepted or rejected.
 160  */
 161 int rxrpc_service_prealloc(struct rxrpc_sock *rx, gfp_t gfp)
 162 {
 163         struct rxrpc_backlog *b = rx->backlog;
 164
 165         if (!b) {
 166                 b = kzalloc(sizeof(struct rxrpc_backlog), gfp);
 167                 if (!b)
 168                         return -ENOMEM;
 169                 rx->backlog = b;
 170         }
 171
 172         if (rx->discard_new_call)
 173                 return 0;
 174
 175         while (rxrpc_service_prealloc_one(rx, b, NULL, NULL, 0, gfp,
 176                                           atomic_inc_return(&rxrpc_debug_id)) == 0)
 177                 ;
 178
 179         return 0;
 180 }
 181
 182 /*
 183  * Discard the preallocation on a service.
 184  */
 185 void rxrpc_discard_prealloc(struct rxrpc_sock *rx)
 186 {
 187         struct rxrpc_backlog *b = rx->backlog;
 188         struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
 189         unsigned int size = RXRPC_BACKLOG_MAX, head, tail;
 190
 191         if (!b)
 192                 return;
 193         rx->backlog = NULL;
 194
 195         /* Make sure that there aren't any incoming calls in progress before we
 196          * clear the preallocation buffers.
 197          */
 198         spin_lock_bh(&rx->incoming_lock);
 199         spin_unlock_bh(&rx->incoming_lock);
 200
 201         head = b->peer_backlog_head;
 202         tail = b->peer_backlog_tail;
 203         while (CIRC_CNT(head, tail, size) > 0) {
 204                 struct rxrpc_peer *peer = b->peer_backlog[tail];
 205                 kfree(peer);
 206                 tail = (tail + 1) & (size - 1);
 207         }
 208
 209         head = b->conn_backlog_head;
 210         tail = b->conn_backlog_tail;
 211         while (CIRC_CNT(head, tail, size) > 0) {
 212                 struct rxrpc_connection *conn = b->conn_backlog[tail];
 213                 write_lock(&rxnet->conn_lock);
 214                 list_del(&conn->link);
 215                 list_del(&conn->proc_link);
 216                 write_unlock(&rxnet->conn_lock);
 217                 kfree(conn);
 218                 if (atomic_dec_and_test(&rxnet->nr_conns))
 219                         wake_up_var(&rxnet->nr_conns);
 220                 tail = (tail + 1) & (size - 1);
 221         }
 222
 223         head = b->call_backlog_head;
 224         tail = b->call_backlog_tail;
 225         while (CIRC_CNT(head, tail, size) > 0) {
 226                 struct rxrpc_call *call = b->call_backlog[tail];
 227                 rcu_assign_pointer(call->socket, rx);
 228                 if (rx->discard_new_call) {
 229                         _debug("discard %lx", call->user_call_ID);
 230                         rx->discard_new_call(call, call->user_call_ID);
 231                         rxrpc_put_call(call, rxrpc_call_put_kernel);
 232                 }
 233                 rxrpc_call_completed(call);
 234                 rxrpc_release_call(rx, call);
 235                 rxrpc_put_call(call, rxrpc_call_put);
 236                 tail = (tail + 1) & (size - 1);
 237         }
 238
 239         kfree(b);
 240 }
 241
 242 /*
 243  * Allocate a new incoming call from the prealloc pool, along with a connection
 244  * and a peer as necessary.
 245  */
 246 static struct rxrpc_call *rxrpc_alloc_incoming_call(struct rxrpc_sock *rx,
 247                                                     struct rxrpc_local *local,
 248                                                     struct rxrpc_peer *peer,
 249                                                     struct rxrpc_connection *conn,
 250                                                     struct sk_buff *skb)
 251 {
 252         struct rxrpc_backlog *b = rx->backlog;
 253         struct rxrpc_call *call;
 254         unsigned short call_head, conn_head, peer_head;
 255         unsigned short call_tail, conn_tail, peer_tail;
 256         unsigned short call_count, conn_count;
 257
 258         /* #calls >= #conns >= #peers must hold true. */
 259         call_head = smp_load_acquire(&b->call_backlog_head);
 260         call_tail = b->call_backlog_tail;
 261         call_count = CIRC_CNT(call_head, call_tail, RXRPC_BACKLOG_MAX);
 262         conn_head = smp_load_acquire(&b->conn_backlog_head);
 263         conn_tail = b->conn_backlog_tail;
 264         conn_count = CIRC_CNT(conn_head, conn_tail, RXRPC_BACKLOG_MAX);
 265         ASSERTCMP(conn_count, >=, call_count);
 266         peer_head = smp_load_acquire(&b->peer_backlog_head);
 267         peer_tail = b->peer_backlog_tail;
 268         ASSERTCMP(CIRC_CNT(peer_head, peer_tail, RXRPC_BACKLOG_MAX), >=,
 269                   conn_count);
 270
 271         if (call_count == 0)
 272                 return NULL;
 273
 274         if (!conn) {
 275                 if (peer && !rxrpc_get_peer_maybe(peer))
 276                         peer = NULL;
 277                 if (!peer) {
 278                         peer = b->peer_backlog[peer_tail];
 279                         if (rxrpc_extract_addr_from_skb(&peer->srx, skb) < 0)
 280                                 return NULL;
 281                         b->peer_backlog[peer_tail] = NULL;
 282                         smp_store_release(&b->peer_backlog_tail,
 283                                           (peer_tail + 1) &
 284                                           (RXRPC_BACKLOG_MAX - 1));
 285
 286                         rxrpc_new_incoming_peer(rx, local, peer);
 287                 }
 288
 289                 /* Now allocate and set up the connection */
 290                 conn = b->conn_backlog[conn_tail];
 291                 b->conn_backlog[conn_tail] = NULL;
 292                 smp_store_release(&b->conn_backlog_tail,
 293                                   (conn_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
 294                 conn->params.local = rxrpc_get_local(local);
 295                 conn->params.peer = peer;
 296                 rxrpc_see_connection(conn);
 297                 rxrpc_new_incoming_connection(rx, conn, skb);
 298         } else {
 299                 rxrpc_get_connection(conn);
 300         }
 301
 302         /* And now we can allocate and set up a new call */
 303         call = b->call_backlog[call_tail];
 304         b->call_backlog[call_tail] = NULL;
 305         smp_store_release(&b->call_backlog_tail,
 306                           (call_tail + 1) & (RXRPC_BACKLOG_MAX - 1));
 307
 308         rxrpc_see_call(call);
 309         call->conn = conn;
 310         call->peer = rxrpc_get_peer(conn->params.peer);
 311         call->cong_cwnd = call->peer->cong_cwnd;
 312         return call;
 313 }
 314
 315 /*
 316  * Set up a new incoming call.  Called in BH context with the RCU read lock
 317  * held.
 318  *
 319  * If this is for a kernel service, when we allocate the call, it will have
 320  * three refs on it: (1) the kernel service, (2) the user_call_ID tree, (3) the
 321  * retainer ref obtained from the backlog buffer.  Prealloc calls for userspace
 322  * services only have the ref from the backlog buffer.  We want to pass this
 323  * ref to non-BH context to dispose of.
 324  *
 325  * If we want to report an error, we mark the skb with the packet type and
 326  * abort code and return NULL.
 327  *
 328  * The call is returned with the user access mutex held.
 329  */
 330 struct rxrpc_call *rxrpc_new_incoming_call(struct rxrpc_local *local,
 331                                            struct rxrpc_sock *rx,
 332                                            struct sk_buff *skb)
 333 {
 334         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 335         struct rxrpc_connection *conn;
 336         struct rxrpc_peer *peer = NULL;
 337         struct rxrpc_call *call;
 338
 339         _enter("");
 340
 341         spin_lock(&rx->incoming_lock);
 342         if (rx->sk.sk_state == RXRPC_SERVER_LISTEN_DISABLED ||
 343             rx->sk.sk_state == RXRPC_CLOSE) {
 344                 trace_rxrpc_abort(0, "CLS", sp->hdr.cid, sp->hdr.callNumber,
 345                                   sp->hdr.seq, RX_INVALID_OPERATION, ESHUTDOWN);
 346                 skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
 347                 skb->priority = RX_INVALID_OPERATION;
 348                 _leave(" = NULL [close]");
 349                 call = NULL;
 350                 goto out;
 351         }
 352
 353         /* The peer, connection and call may all have sprung into existence due
 354          * to a duplicate packet being handled on another CPU in parallel, so
 355          * we have to recheck the routing.  However, we're now holding
 356          * rx->incoming_lock, so the values should remain stable.
 357          */
 358         conn = rxrpc_find_connection_rcu(local, skb, &peer);
 359
 360         call = rxrpc_alloc_incoming_call(rx, local, peer, conn, skb);
 361         if (!call) {
 362                 skb->mark = RXRPC_SKB_MARK_REJECT_BUSY;
 363                 _leave(" = NULL [busy]");
 364                 call = NULL;
 365                 goto out;
 366         }
 367
 368         trace_rxrpc_receive(call, rxrpc_receive_incoming,
 369                             sp->hdr.serial, sp->hdr.seq);
 370
 371         /* Lock the call to prevent rxrpc_kernel_send/recv_data() and
 372          * sendmsg()/recvmsg() inconveniently stealing the mutex once the
 373          * notification is generated.
 374          *
 375          * The BUG should never happen because the kernel should be well
 376          * behaved enough not to access the call before the first notification
 377          * event and userspace is prevented from doing so until the state is
 378          * appropriate.
 379          */
 380         if (!mutex_trylock(&call->user_mutex))
 381                 BUG();
 382
 383         /* Make the call live. */
 384         rxrpc_incoming_call(rx, call, skb);
 385         conn = call->conn;
 386
 387         if (rx->notify_new_call)
 388                 rx->notify_new_call(&rx->sk, call, call->user_call_ID);
 389         else
 390                 sk_acceptq_added(&rx->sk);
 391
 392         spin_lock(&conn->state_lock);
 393         switch (conn->state) {
 394         case RXRPC_CONN_SERVICE_UNSECURED:
 395                 conn->state = RXRPC_CONN_SERVICE_CHALLENGING;
 396                 set_bit(RXRPC_CONN_EV_CHALLENGE, &call->conn->events);
 397                 rxrpc_queue_conn(call->conn);
 398                 break;
 399
 400         case RXRPC_CONN_SERVICE:
 401                 write_lock(&call->state_lock);
 402                 if (call->state < RXRPC_CALL_COMPLETE) {
 403                         if (rx->discard_new_call)
 404                                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 405                         else
 406                                 call->state = RXRPC_CALL_SERVER_ACCEPTING;
 407                 }
 408                 write_unlock(&call->state_lock);
 409                 break;
 410
 411         case RXRPC_CONN_REMOTELY_ABORTED:
 412                 rxrpc_set_call_completion(call, RXRPC_CALL_REMOTELY_ABORTED,
 413                                           conn->abort_code, conn->error);
 414                 break;
 415         case RXRPC_CONN_LOCALLY_ABORTED:
 416                 rxrpc_abort_call("CON", call, sp->hdr.seq,
 417                                  conn->abort_code, conn->error);
 418                 break;
 419         default:
 420                 BUG();
 421         }
 422         spin_unlock(&conn->state_lock);
 423
 424         if (call->state == RXRPC_CALL_SERVER_ACCEPTING)
 425                 rxrpc_notify_socket(call);
 426
 427         /* We have to discard the prealloc queue's ref here and rely on a
 428          * combination of the RCU read lock and refs held either by the socket
 429          * (recvmsg queue, to-be-accepted queue or user ID tree) or the kernel
 430          * service to prevent the call from being deallocated too early.
 431          */
 432         rxrpc_put_call(call, rxrpc_call_put);
 433
 434         _leave(" = %p{%d}", call, call->debug_id);
 435 out:
 436         spin_unlock(&rx->incoming_lock);
 437         return call;
 438 }
 439
 440 /*
 441  * handle acceptance of a call by userspace
 442  * - assign the user call ID to the call at the front of the queue
 443  * - called with the socket locked.
 444  */
 445 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 446                                      unsigned long user_call_ID,
 447                                      rxrpc_notify_rx_t notify_rx)
 448         __releases(&rx->sk.sk_lock.slock)
 449         __acquires(call->user_mutex)
 450 {
 451         struct rxrpc_call *call;
 452         struct rb_node *parent, **pp;
 453         int ret;
 454
 455         _enter(",%lx", user_call_ID);
 456
 457         ASSERT(!irqs_disabled());
 458
 459         write_lock(&rx->call_lock);
 460
 461         if (list_empty(&rx->to_be_accepted)) {
 462                 write_unlock(&rx->call_lock);
 463                 release_sock(&rx->sk);
 464                 kleave(" = -ENODATA [empty]");
 465                 return ERR_PTR(-ENODATA);
 466         }
 467
 468         /* check the user ID isn't already in use */
 469         pp = &rx->calls.rb_node;
 470         parent = NULL;
 471         while (*pp) {
 472                 parent = *pp;
 473                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 474
 475                 if (user_call_ID < call->user_call_ID)
 476                         pp = &(*pp)->rb_left;
 477                 else if (user_call_ID > call->user_call_ID)
 478                         pp = &(*pp)->rb_right;
 479                 else
 480                         goto id_in_use;
 481         }
 482
 483         /* Dequeue the first call and check it's still valid.  We gain
 484          * responsibility for the queue's reference.
 485          */
 486         call = list_entry(rx->to_be_accepted.next,
 487                           struct rxrpc_call, accept_link);
 488         write_unlock(&rx->call_lock);
 489
 490         /* We need to gain the mutex from the interrupt handler without
 491          * upsetting lockdep, so we have to release it there and take it here.
 492          * We are, however, still holding the socket lock, so other accepts
 493          * must wait for us and no one can add the user ID behind our backs.
 494          */
 495         if (mutex_lock_interruptible(&call->user_mutex) < 0) {
 496                 release_sock(&rx->sk);
 497                 kleave(" = -ERESTARTSYS");
 498                 return ERR_PTR(-ERESTARTSYS);
 499         }
 500
 501         write_lock(&rx->call_lock);
 502         list_del_init(&call->accept_link);
 503         sk_acceptq_removed(&rx->sk);
 504         rxrpc_see_call(call);
 505
 506         /* Find the user ID insertion point. */
 507         pp = &rx->calls.rb_node;
 508         parent = NULL;
 509         while (*pp) {
 510                 parent = *pp;
 511                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 512
 513                 if (user_call_ID < call->user_call_ID)
 514                         pp = &(*pp)->rb_left;
 515                 else if (user_call_ID > call->user_call_ID)
 516                         pp = &(*pp)->rb_right;
 517                 else
 518                         BUG();
 519         }
 520
 521         write_lock_bh(&call->state_lock);
 522         switch (call->state) {
 523         case RXRPC_CALL_SERVER_ACCEPTING:
 524                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 525                 break;
 526         case RXRPC_CALL_COMPLETE:
 527                 ret = call->error;
 528                 goto out_release;
 529         default:
 530                 BUG();
 531         }
 532
 533         /* formalise the acceptance */
 534         call->notify_rx = notify_rx;
 535         call->user_call_ID = user_call_ID;
 536         rxrpc_get_call(call, rxrpc_call_got_userid);
 537         rb_link_node(&call->sock_node, parent, pp);
 538         rb_insert_color(&call->sock_node, &rx->calls);
 539         if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
 540                 BUG();
 541
 542         write_unlock_bh(&call->state_lock);
 543         write_unlock(&rx->call_lock);
 544         rxrpc_notify_socket(call);
 545         rxrpc_service_prealloc(rx, GFP_KERNEL);
 546         release_sock(&rx->sk);
 547         _leave(" = %p{%d}", call, call->debug_id);
 548         return call;
 549
 550 out_release:
 551         _debug("release %p", call);
 552         write_unlock_bh(&call->state_lock);
 553         write_unlock(&rx->call_lock);
 554         rxrpc_release_call(rx, call);
 555         rxrpc_put_call(call, rxrpc_call_put);
 556         goto out;
 557
 558 id_in_use:
 559         ret = -EBADSLT;
 560         write_unlock(&rx->call_lock);
 561 out:
 562         rxrpc_service_prealloc(rx, GFP_KERNEL);
 563         release_sock(&rx->sk);
 564         _leave(" = %d", ret);
 565         return ERR_PTR(ret);
 566 }
 567
 568 /*
 569  * Handle rejection of a call by userspace
 570  * - reject the call at the front of the queue
 571  */
 572 int rxrpc_reject_call(struct rxrpc_sock *rx)
 573 {
 574         struct rxrpc_call *call;
 575         bool abort = false;
 576         int ret;
 577
 578         _enter("");
 579
 580         ASSERT(!irqs_disabled());
 581
 582         write_lock(&rx->call_lock);
 583
 584         if (list_empty(&rx->to_be_accepted)) {
 585                 write_unlock(&rx->call_lock);
 586                 return -ENODATA;
 587         }
 588
 589         /* Dequeue the first call and check it's still valid.  We gain
 590          * responsibility for the queue's reference.
 591          */
 592         call = list_entry(rx->to_be_accepted.next,
 593                           struct rxrpc_call, accept_link);
 594         list_del_init(&call->accept_link);
 595         sk_acceptq_removed(&rx->sk);
 596         rxrpc_see_call(call);
 597
 598         write_lock_bh(&call->state_lock);
 599         switch (call->state) {
 600         case RXRPC_CALL_SERVER_ACCEPTING:
 601                 __rxrpc_abort_call("REJ", call, 1, RX_USER_ABORT, -ECONNABORTED);
 602                 abort = true;
 603                 /* fall through */
 604         case RXRPC_CALL_COMPLETE:
 605                 ret = call->error;
 606                 goto out_discard;
 607         default:
 608                 BUG();
 609         }
 610
 611 out_discard:
 612         write_unlock_bh(&call->state_lock);
 613         write_unlock(&rx->call_lock);
 614         if (abort) {
 615                 rxrpc_send_abort_packet(call);
 616                 rxrpc_release_call(rx, call);
 617                 rxrpc_put_call(call, rxrpc_call_put);
 618         }
 619         rxrpc_service_prealloc(rx, GFP_KERNEL);
 620         _leave(" = %d", ret);
 621         return ret;
 622 }
 623
 624 /*
 625  * rxrpc_kernel_charge_accept - Charge up socket with preallocated calls
 626  * @sock: The socket on which to preallocate
 627  * @notify_rx: Event notification function for the call
 628  * @user_attach_call: Func to attach call to user_call_ID
 629  * @user_call_ID: The tag to attach to the preallocated call
 630  * @gfp: The allocation conditions.
 631  * @debug_id: The tracing debug ID.
 632  *
 633  * Charge up the socket with preallocated calls, each with a user ID.  A
 634  * function should be provided to effect the attachment from the user's side.
 635  * The user is given a ref to hold on the call.
 636  *
 637  * Note that the call may be come connected before this function returns.
 638  */
 639 int rxrpc_kernel_charge_accept(struct socket *sock,
 640                                rxrpc_notify_rx_t notify_rx,
 641                                rxrpc_user_attach_call_t user_attach_call,
 642                                unsigned long user_call_ID, gfp_t gfp,
 643                                unsigned int debug_id)
 644 {
 645         struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
 646         struct rxrpc_backlog *b = rx->backlog;
 647
 648         if (sock->sk->sk_state == RXRPC_CLOSE)
 649                 return -ESHUTDOWN;
 650
 651         return rxrpc_service_prealloc_one(rx, b, notify_rx,
 652                                           user_attach_call, user_call_ID,
 653                                           gfp, debug_id);
 654 }
 655 EXPORT_SYMBOL(rxrpc_kernel_charge_accept);