net/rxrpc/ar-ack.c

   1 /* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
   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 #include <linux/module.h>
  13 #include <linux/circ_buf.h>
  14 #include <linux/net.h>
  15 #include <linux/skbuff.h>
  16 #include <linux/slab.h>
  17 #include <linux/udp.h>
  18 #include <net/sock.h>
  19 #include <net/af_rxrpc.h>
  20 #include "ar-internal.h"
  21
  22 static unsigned int rxrpc_ack_defer = 1;
  23
  24 static const char *rxrpc_acks(u8 reason)
  25 {
  26         static const char *const str[] = {
  27                 "---", "REQ", "DUP", "OOS", "WIN", "MEM", "PNG", "PNR", "DLY",
  28                 "IDL", "-?-"
  29         };
  30
  31         if (reason >= ARRAY_SIZE(str))
  32                 reason = ARRAY_SIZE(str) - 1;
  33         return str[reason];
  34 }
  35
  36 static const s8 rxrpc_ack_priority[] = {
  37         [0]                             = 0,
  38         [RXRPC_ACK_DELAY]               = 1,
  39         [RXRPC_ACK_REQUESTED]           = 2,
  40         [RXRPC_ACK_IDLE]                = 3,
  41         [RXRPC_ACK_PING_RESPONSE]       = 4,
  42         [RXRPC_ACK_DUPLICATE]           = 5,
  43         [RXRPC_ACK_OUT_OF_SEQUENCE]     = 6,
  44         [RXRPC_ACK_EXCEEDS_WINDOW]      = 7,
  45         [RXRPC_ACK_NOSPACE]             = 8,
  46 };
  47
  48 /*
  49  * propose an ACK be sent
  50  */
  51 void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
  52                          __be32 serial, bool immediate)
  53 {
  54         unsigned long expiry;
  55         s8 prior = rxrpc_ack_priority[ack_reason];
  56
  57         ASSERTCMP(prior, >, 0);
  58
  59         _enter("{%d},%s,%%%x,%u",
  60                call->debug_id, rxrpc_acks(ack_reason), ntohl(serial),
  61                immediate);
  62
  63         if (prior < rxrpc_ack_priority[call->ackr_reason]) {
  64                 if (immediate)
  65                         goto cancel_timer;
  66                 return;
  67         }
  68
  69         /* update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
  70          * numbers */
  71         if (prior == rxrpc_ack_priority[call->ackr_reason]) {
  72                 if (prior <= 4)
  73                         call->ackr_serial = serial;
  74                 if (immediate)
  75                         goto cancel_timer;
  76                 return;
  77         }
  78
  79         call->ackr_reason = ack_reason;
  80         call->ackr_serial = serial;
  81
  82         switch (ack_reason) {
  83         case RXRPC_ACK_DELAY:
  84                 _debug("run delay timer");
  85                 call->ack_timer.expires = jiffies + rxrpc_ack_timeout * HZ;
  86                 add_timer(&call->ack_timer);
  87                 return;
  88
  89         case RXRPC_ACK_IDLE:
  90                 if (!immediate) {
  91                         _debug("run defer timer");
  92                         expiry = 1;
  93                         goto run_timer;
  94                 }
  95                 goto cancel_timer;
  96
  97         case RXRPC_ACK_REQUESTED:
  98                 if (!rxrpc_ack_defer)
  99                         goto cancel_timer;
 100                 if (!immediate || serial == cpu_to_be32(1)) {
 101                         _debug("run defer timer");
 102                         expiry = rxrpc_ack_defer;
 103                         goto run_timer;
 104                 }
 105
 106         default:
 107                 _debug("immediate ACK");
 108                 goto cancel_timer;
 109         }
 110
 111 run_timer:
 112         expiry += jiffies;
 113         if (!timer_pending(&call->ack_timer) ||
 114             time_after(call->ack_timer.expires, expiry))
 115                 mod_timer(&call->ack_timer, expiry);
 116         return;
 117
 118 cancel_timer:
 119         _debug("cancel timer %%%u", ntohl(serial));
 120         try_to_del_timer_sync(&call->ack_timer);
 121         read_lock_bh(&call->state_lock);
 122         if (call->state <= RXRPC_CALL_COMPLETE &&
 123             !test_and_set_bit(RXRPC_CALL_ACK, &call->events))
 124                 rxrpc_queue_call(call);
 125         read_unlock_bh(&call->state_lock);
 126 }
 127
 128 /*
 129  * propose an ACK be sent, locking the call structure
 130  */
 131 void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
 132                        __be32 serial, bool immediate)
 133 {
 134         s8 prior = rxrpc_ack_priority[ack_reason];
 135
 136         if (prior > rxrpc_ack_priority[call->ackr_reason]) {
 137                 spin_lock_bh(&call->lock);
 138                 __rxrpc_propose_ACK(call, ack_reason, serial, immediate);
 139                 spin_unlock_bh(&call->lock);
 140         }
 141 }
 142
 143 /*
 144  * set the resend timer
 145  */
 146 static void rxrpc_set_resend(struct rxrpc_call *call, u8 resend,
 147                              unsigned long resend_at)
 148 {
 149         read_lock_bh(&call->state_lock);
 150         if (call->state >= RXRPC_CALL_COMPLETE)
 151                 resend = 0;
 152
 153         if (resend & 1) {
 154                 _debug("SET RESEND");
 155                 set_bit(RXRPC_CALL_RESEND, &call->events);
 156         }
 157
 158         if (resend & 2) {
 159                 _debug("MODIFY RESEND TIMER");
 160                 set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 161                 mod_timer(&call->resend_timer, resend_at);
 162         } else {
 163                 _debug("KILL RESEND TIMER");
 164                 del_timer_sync(&call->resend_timer);
 165                 clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 166                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 167         }
 168         read_unlock_bh(&call->state_lock);
 169 }
 170
 171 /*
 172  * resend packets
 173  */
 174 static void rxrpc_resend(struct rxrpc_call *call)
 175 {
 176         struct rxrpc_skb_priv *sp;
 177         struct rxrpc_header *hdr;
 178         struct sk_buff *txb;
 179         unsigned long *p_txb, resend_at;
 180         int loop, stop;
 181         u8 resend;
 182
 183         _enter("{%d,%d,%d,%d},",
 184                call->acks_hard, call->acks_unacked,
 185                atomic_read(&call->sequence),
 186                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
 187
 188         stop = 0;
 189         resend = 0;
 190         resend_at = 0;
 191
 192         for (loop = call->acks_tail;
 193              loop != call->acks_head || stop;
 194              loop = (loop + 1) &  (call->acks_winsz - 1)
 195              ) {
 196                 p_txb = call->acks_window + loop;
 197                 smp_read_barrier_depends();
 198                 if (*p_txb & 1)
 199                         continue;
 200
 201                 txb = (struct sk_buff *) *p_txb;
 202                 sp = rxrpc_skb(txb);
 203
 204                 if (sp->need_resend) {
 205                         sp->need_resend = false;
 206
 207                         /* each Tx packet has a new serial number */
 208                         sp->hdr.serial =
 209                                 htonl(atomic_inc_return(&call->conn->serial));
 210
 211                         hdr = (struct rxrpc_header *) txb->head;
 212                         hdr->serial = sp->hdr.serial;
 213
 214                         _proto("Tx DATA %%%u { #%d }",
 215                                ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
 216                         if (rxrpc_send_packet(call->conn->trans, txb) < 0) {
 217                                 stop = 0;
 218                                 sp->resend_at = jiffies + 3;
 219                         } else {
 220                                 sp->resend_at =
 221                                         jiffies + rxrpc_resend_timeout * HZ;
 222                         }
 223                 }
 224
 225                 if (time_after_eq(jiffies + 1, sp->resend_at)) {
 226                         sp->need_resend = true;
 227                         resend |= 1;
 228                 } else if (resend & 2) {
 229                         if (time_before(sp->resend_at, resend_at))
 230                                 resend_at = sp->resend_at;
 231                 } else {
 232                         resend_at = sp->resend_at;
 233                         resend |= 2;
 234                 }
 235         }
 236
 237         rxrpc_set_resend(call, resend, resend_at);
 238         _leave("");
 239 }
 240
 241 /*
 242  * handle resend timer expiry
 243  */
 244 static void rxrpc_resend_timer(struct rxrpc_call *call)
 245 {
 246         struct rxrpc_skb_priv *sp;
 247         struct sk_buff *txb;
 248         unsigned long *p_txb, resend_at;
 249         int loop;
 250         u8 resend;
 251
 252         _enter("%d,%d,%d",
 253                call->acks_tail, call->acks_unacked, call->acks_head);
 254
 255         if (call->state >= RXRPC_CALL_COMPLETE)
 256                 return;
 257
 258         resend = 0;
 259         resend_at = 0;
 260
 261         for (loop = call->acks_unacked;
 262              loop != call->acks_head;
 263              loop = (loop + 1) &  (call->acks_winsz - 1)
 264              ) {
 265                 p_txb = call->acks_window + loop;
 266                 smp_read_barrier_depends();
 267                 txb = (struct sk_buff *) (*p_txb & ~1);
 268                 sp = rxrpc_skb(txb);
 269
 270                 ASSERT(!(*p_txb & 1));
 271
 272                 if (sp->need_resend) {
 273                         ;
 274                 } else if (time_after_eq(jiffies + 1, sp->resend_at)) {
 275                         sp->need_resend = true;
 276                         resend |= 1;
 277                 } else if (resend & 2) {
 278                         if (time_before(sp->resend_at, resend_at))
 279                                 resend_at = sp->resend_at;
 280                 } else {
 281                         resend_at = sp->resend_at;
 282                         resend |= 2;
 283                 }
 284         }
 285
 286         rxrpc_set_resend(call, resend, resend_at);
 287         _leave("");
 288 }
 289
 290 /*
 291  * process soft ACKs of our transmitted packets
 292  * - these indicate packets the peer has or has not received, but hasn't yet
 293  *   given to the consumer, and so can still be discarded and re-requested
 294  */
 295 static int rxrpc_process_soft_ACKs(struct rxrpc_call *call,
 296                                    struct rxrpc_ackpacket *ack,
 297                                    struct sk_buff *skb)
 298 {
 299         struct rxrpc_skb_priv *sp;
 300         struct sk_buff *txb;
 301         unsigned long *p_txb, resend_at;
 302         int loop;
 303         u8 sacks[RXRPC_MAXACKS], resend;
 304
 305         _enter("{%d,%d},{%d},",
 306                call->acks_hard,
 307                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz),
 308                ack->nAcks);
 309
 310         if (skb_copy_bits(skb, 0, sacks, ack->nAcks) < 0)
 311                 goto protocol_error;
 312
 313         resend = 0;
 314         resend_at = 0;
 315         for (loop = 0; loop < ack->nAcks; loop++) {
 316                 p_txb = call->acks_window;
 317                 p_txb += (call->acks_tail + loop) & (call->acks_winsz - 1);
 318                 smp_read_barrier_depends();
 319                 txb = (struct sk_buff *) (*p_txb & ~1);
 320                 sp = rxrpc_skb(txb);
 321
 322                 switch (sacks[loop]) {
 323                 case RXRPC_ACK_TYPE_ACK:
 324                         sp->need_resend = false;
 325                         *p_txb |= 1;
 326                         break;
 327                 case RXRPC_ACK_TYPE_NACK:
 328                         sp->need_resend = true;
 329                         *p_txb &= ~1;
 330                         resend = 1;
 331                         break;
 332                 default:
 333                         _debug("Unsupported ACK type %d", sacks[loop]);
 334                         goto protocol_error;
 335                 }
 336         }
 337
 338         smp_mb();
 339         call->acks_unacked = (call->acks_tail + loop) & (call->acks_winsz - 1);
 340
 341         /* anything not explicitly ACK'd is implicitly NACK'd, but may just not
 342          * have been received or processed yet by the far end */
 343         for (loop = call->acks_unacked;
 344              loop != call->acks_head;
 345              loop = (loop + 1) &  (call->acks_winsz - 1)
 346              ) {
 347                 p_txb = call->acks_window + loop;
 348                 smp_read_barrier_depends();
 349                 txb = (struct sk_buff *) (*p_txb & ~1);
 350                 sp = rxrpc_skb(txb);
 351
 352                 if (*p_txb & 1) {
 353                         /* packet must have been discarded */
 354                         sp->need_resend = true;
 355                         *p_txb &= ~1;
 356                         resend |= 1;
 357                 } else if (sp->need_resend) {
 358                         ;
 359                 } else if (time_after_eq(jiffies + 1, sp->resend_at)) {
 360                         sp->need_resend = true;
 361                         resend |= 1;
 362                 } else if (resend & 2) {
 363                         if (time_before(sp->resend_at, resend_at))
 364                                 resend_at = sp->resend_at;
 365                 } else {
 366                         resend_at = sp->resend_at;
 367                         resend |= 2;
 368                 }
 369         }
 370
 371         rxrpc_set_resend(call, resend, resend_at);
 372         _leave(" = 0");
 373         return 0;
 374
 375 protocol_error:
 376         _leave(" = -EPROTO");
 377         return -EPROTO;
 378 }
 379
 380 /*
 381  * discard hard-ACK'd packets from the Tx window
 382  */
 383 static void rxrpc_rotate_tx_window(struct rxrpc_call *call, u32 hard)
 384 {
 385         unsigned long _skb;
 386         int tail = call->acks_tail, old_tail;
 387         int win = CIRC_CNT(call->acks_head, tail, call->acks_winsz);
 388
 389         _enter("{%u,%u},%u", call->acks_hard, win, hard);
 390
 391         ASSERTCMP(hard - call->acks_hard, <=, win);
 392
 393         while (call->acks_hard < hard) {
 394                 smp_read_barrier_depends();
 395                 _skb = call->acks_window[tail] & ~1;
 396                 rxrpc_free_skb((struct sk_buff *) _skb);
 397                 old_tail = tail;
 398                 tail = (tail + 1) & (call->acks_winsz - 1);
 399                 call->acks_tail = tail;
 400                 if (call->acks_unacked == old_tail)
 401                         call->acks_unacked = tail;
 402                 call->acks_hard++;
 403         }
 404
 405         wake_up(&call->tx_waitq);
 406 }
 407
 408 /*
 409  * clear the Tx window in the event of a failure
 410  */
 411 static void rxrpc_clear_tx_window(struct rxrpc_call *call)
 412 {
 413         rxrpc_rotate_tx_window(call, atomic_read(&call->sequence));
 414 }
 415
 416 /*
 417  * drain the out of sequence received packet queue into the packet Rx queue
 418  */
 419 static int rxrpc_drain_rx_oos_queue(struct rxrpc_call *call)
 420 {
 421         struct rxrpc_skb_priv *sp;
 422         struct sk_buff *skb;
 423         bool terminal;
 424         int ret;
 425
 426         _enter("{%d,%d}", call->rx_data_post, call->rx_first_oos);
 427
 428         spin_lock_bh(&call->lock);
 429
 430         ret = -ECONNRESET;
 431         if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
 432                 goto socket_unavailable;
 433
 434         skb = skb_dequeue(&call->rx_oos_queue);
 435         if (skb) {
 436                 sp = rxrpc_skb(skb);
 437
 438                 _debug("drain OOS packet %d [%d]",
 439                        ntohl(sp->hdr.seq), call->rx_first_oos);
 440
 441                 if (ntohl(sp->hdr.seq) != call->rx_first_oos) {
 442                         skb_queue_head(&call->rx_oos_queue, skb);
 443                         call->rx_first_oos = ntohl(rxrpc_skb(skb)->hdr.seq);
 444                         _debug("requeue %p {%u}", skb, call->rx_first_oos);
 445                 } else {
 446                         skb->mark = RXRPC_SKB_MARK_DATA;
 447                         terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
 448                                 !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
 449                         ret = rxrpc_queue_rcv_skb(call, skb, true, terminal);
 450                         BUG_ON(ret < 0);
 451                         _debug("drain #%u", call->rx_data_post);
 452                         call->rx_data_post++;
 453
 454                         /* find out what the next packet is */
 455                         skb = skb_peek(&call->rx_oos_queue);
 456                         if (skb)
 457                                 call->rx_first_oos =
 458                                         ntohl(rxrpc_skb(skb)->hdr.seq);
 459                         else
 460                                 call->rx_first_oos = 0;
 461                         _debug("peek %p {%u}", skb, call->rx_first_oos);
 462                 }
 463         }
 464
 465         ret = 0;
 466 socket_unavailable:
 467         spin_unlock_bh(&call->lock);
 468         _leave(" = %d", ret);
 469         return ret;
 470 }
 471
 472 /*
 473  * insert an out of sequence packet into the buffer
 474  */
 475 static void rxrpc_insert_oos_packet(struct rxrpc_call *call,
 476                                     struct sk_buff *skb)
 477 {
 478         struct rxrpc_skb_priv *sp, *psp;
 479         struct sk_buff *p;
 480         u32 seq;
 481
 482         sp = rxrpc_skb(skb);
 483         seq = ntohl(sp->hdr.seq);
 484         _enter(",,{%u}", seq);
 485
 486         skb->destructor = rxrpc_packet_destructor;
 487         ASSERTCMP(sp->call, ==, NULL);
 488         sp->call = call;
 489         rxrpc_get_call(call);
 490
 491         /* insert into the buffer in sequence order */
 492         spin_lock_bh(&call->lock);
 493
 494         skb_queue_walk(&call->rx_oos_queue, p) {
 495                 psp = rxrpc_skb(p);
 496                 if (ntohl(psp->hdr.seq) > seq) {
 497                         _debug("insert oos #%u before #%u",
 498                                seq, ntohl(psp->hdr.seq));
 499                         skb_insert(p, skb, &call->rx_oos_queue);
 500                         goto inserted;
 501                 }
 502         }
 503
 504         _debug("append oos #%u", seq);
 505         skb_queue_tail(&call->rx_oos_queue, skb);
 506 inserted:
 507
 508         /* we might now have a new front to the queue */
 509         if (call->rx_first_oos == 0 || seq < call->rx_first_oos)
 510                 call->rx_first_oos = seq;
 511
 512         read_lock(&call->state_lock);
 513         if (call->state < RXRPC_CALL_COMPLETE &&
 514             call->rx_data_post == call->rx_first_oos) {
 515                 _debug("drain rx oos now");
 516                 set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
 517         }
 518         read_unlock(&call->state_lock);
 519
 520         spin_unlock_bh(&call->lock);
 521         _leave(" [stored #%u]", call->rx_first_oos);
 522 }
 523
 524 /*
 525  * clear the Tx window on final ACK reception
 526  */
 527 static void rxrpc_zap_tx_window(struct rxrpc_call *call)
 528 {
 529         struct rxrpc_skb_priv *sp;
 530         struct sk_buff *skb;
 531         unsigned long _skb, *acks_window;
 532         u8 winsz = call->acks_winsz;
 533         int tail;
 534
 535         acks_window = call->acks_window;
 536         call->acks_window = NULL;
 537
 538         while (CIRC_CNT(call->acks_head, call->acks_tail, winsz) > 0) {
 539                 tail = call->acks_tail;
 540                 smp_read_barrier_depends();
 541                 _skb = acks_window[tail] & ~1;
 542                 smp_mb();
 543                 call->acks_tail = (call->acks_tail + 1) & (winsz - 1);
 544
 545                 skb = (struct sk_buff *) _skb;
 546                 sp = rxrpc_skb(skb);
 547                 _debug("+++ clear Tx %u", ntohl(sp->hdr.seq));
 548                 rxrpc_free_skb(skb);
 549         }
 550
 551         kfree(acks_window);
 552 }
 553
 554 /*
 555  * process the extra information that may be appended to an ACK packet
 556  */
 557 static void rxrpc_extract_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 558                                   unsigned int latest, int nAcks)
 559 {
 560         struct rxrpc_ackinfo ackinfo;
 561         struct rxrpc_peer *peer;
 562         unsigned int mtu;
 563
 564         if (skb_copy_bits(skb, nAcks + 3, &ackinfo, sizeof(ackinfo)) < 0) {
 565                 _leave(" [no ackinfo]");
 566                 return;
 567         }
 568
 569         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 570                latest,
 571                ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU),
 572                ntohl(ackinfo.rwind), ntohl(ackinfo.jumbo_max));
 573
 574         mtu = min(ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU));
 575
 576         peer = call->conn->trans->peer;
 577         if (mtu < peer->maxdata) {
 578                 spin_lock_bh(&peer->lock);
 579                 peer->maxdata = mtu;
 580                 peer->mtu = mtu + peer->hdrsize;
 581                 spin_unlock_bh(&peer->lock);
 582                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 583         }
 584 }
 585
 586 /*
 587  * process packets in the reception queue
 588  */
 589 static int rxrpc_process_rx_queue(struct rxrpc_call *call,
 590                                   u32 *_abort_code)
 591 {
 592         struct rxrpc_ackpacket ack;
 593         struct rxrpc_skb_priv *sp;
 594         struct sk_buff *skb;
 595         bool post_ACK;
 596         int latest;
 597         u32 hard, tx;
 598
 599         _enter("");
 600
 601 process_further:
 602         skb = skb_dequeue(&call->rx_queue);
 603         if (!skb)
 604                 return -EAGAIN;
 605
 606         _net("deferred skb %p", skb);
 607
 608         sp = rxrpc_skb(skb);
 609
 610         _debug("process %s [st %d]", rxrpc_pkts[sp->hdr.type], call->state);
 611
 612         post_ACK = false;
 613
 614         switch (sp->hdr.type) {
 615                 /* data packets that wind up here have been received out of
 616                  * order, need security processing or are jumbo packets */
 617         case RXRPC_PACKET_TYPE_DATA:
 618                 _proto("OOSQ DATA %%%u { #%u }",
 619                        ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
 620
 621                 /* secured packets must be verified and possibly decrypted */
 622                 if (rxrpc_verify_packet(call, skb, _abort_code) < 0)
 623                         goto protocol_error;
 624
 625                 rxrpc_insert_oos_packet(call, skb);
 626                 goto process_further;
 627
 628                 /* partial ACK to process */
 629         case RXRPC_PACKET_TYPE_ACK:
 630                 if (skb_copy_bits(skb, 0, &ack, sizeof(ack)) < 0) {
 631                         _debug("extraction failure");
 632                         goto protocol_error;
 633                 }
 634                 if (!skb_pull(skb, sizeof(ack)))
 635                         BUG();
 636
 637                 latest = ntohl(sp->hdr.serial);
 638                 hard = ntohl(ack.firstPacket);
 639                 tx = atomic_read(&call->sequence);
 640
 641                 _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 642                        latest,
 643                        ntohs(ack.maxSkew),
 644                        hard,
 645                        ntohl(ack.previousPacket),
 646                        ntohl(ack.serial),
 647                        rxrpc_acks(ack.reason),
 648                        ack.nAcks);
 649
 650                 rxrpc_extract_ackinfo(call, skb, latest, ack.nAcks);
 651
 652                 if (ack.reason == RXRPC_ACK_PING) {
 653                         _proto("Rx ACK %%%u PING Request", latest);
 654                         rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 655                                           sp->hdr.serial, true);
 656                 }
 657
 658                 /* discard any out-of-order or duplicate ACKs */
 659                 if (latest - call->acks_latest <= 0) {
 660                         _debug("discard ACK %d <= %d",
 661                                latest, call->acks_latest);
 662                         goto discard;
 663                 }
 664                 call->acks_latest = latest;
 665
 666                 if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
 667                     call->state != RXRPC_CALL_CLIENT_AWAIT_REPLY &&
 668                     call->state != RXRPC_CALL_SERVER_SEND_REPLY &&
 669                     call->state != RXRPC_CALL_SERVER_AWAIT_ACK)
 670                         goto discard;
 671
 672                 _debug("Tx=%d H=%u S=%d", tx, call->acks_hard, call->state);
 673
 674                 if (hard > 0) {
 675                         if (hard - 1 > tx) {
 676                                 _debug("hard-ACK'd packet %d not transmitted"
 677                                        " (%d top)",
 678                                        hard - 1, tx);
 679                                 goto protocol_error;
 680                         }
 681
 682                         if ((call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY ||
 683                              call->state == RXRPC_CALL_SERVER_AWAIT_ACK) &&
 684                             hard > tx)
 685                                 goto all_acked;
 686
 687                         smp_rmb();
 688                         rxrpc_rotate_tx_window(call, hard - 1);
 689                 }
 690
 691                 if (ack.nAcks > 0) {
 692                         if (hard - 1 + ack.nAcks > tx) {
 693                                 _debug("soft-ACK'd packet %d+%d not"
 694                                        " transmitted (%d top)",
 695                                        hard - 1, ack.nAcks, tx);
 696                                 goto protocol_error;
 697                         }
 698
 699                         if (rxrpc_process_soft_ACKs(call, &ack, skb) < 0)
 700                                 goto protocol_error;
 701                 }
 702                 goto discard;
 703
 704                 /* complete ACK to process */
 705         case RXRPC_PACKET_TYPE_ACKALL:
 706                 goto all_acked;
 707
 708                 /* abort and busy are handled elsewhere */
 709         case RXRPC_PACKET_TYPE_BUSY:
 710         case RXRPC_PACKET_TYPE_ABORT:
 711                 BUG();
 712
 713                 /* connection level events - also handled elsewhere */
 714         case RXRPC_PACKET_TYPE_CHALLENGE:
 715         case RXRPC_PACKET_TYPE_RESPONSE:
 716         case RXRPC_PACKET_TYPE_DEBUG:
 717                 BUG();
 718         }
 719
 720         /* if we've had a hard ACK that covers all the packets we've sent, then
 721          * that ends that phase of the operation */
 722 all_acked:
 723         write_lock_bh(&call->state_lock);
 724         _debug("ack all %d", call->state);
 725
 726         switch (call->state) {
 727         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 728                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 729                 break;
 730         case RXRPC_CALL_SERVER_AWAIT_ACK:
 731                 _debug("srv complete");
 732                 call->state = RXRPC_CALL_COMPLETE;
 733                 post_ACK = true;
 734                 break;
 735         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 736         case RXRPC_CALL_SERVER_RECV_REQUEST:
 737                 goto protocol_error_unlock; /* can't occur yet */
 738         default:
 739                 write_unlock_bh(&call->state_lock);
 740                 goto discard; /* assume packet left over from earlier phase */
 741         }
 742
 743         write_unlock_bh(&call->state_lock);
 744
 745         /* if all the packets we sent are hard-ACK'd, then we can discard
 746          * whatever we've got left */
 747         _debug("clear Tx %d",
 748                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
 749
 750         del_timer_sync(&call->resend_timer);
 751         clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 752         clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 753
 754         if (call->acks_window)
 755                 rxrpc_zap_tx_window(call);
 756
 757         if (post_ACK) {
 758                 /* post the final ACK message for userspace to pick up */
 759                 _debug("post ACK");
 760                 skb->mark = RXRPC_SKB_MARK_FINAL_ACK;
 761                 sp->call = call;
 762                 rxrpc_get_call(call);
 763                 spin_lock_bh(&call->lock);
 764                 if (rxrpc_queue_rcv_skb(call, skb, true, true) < 0)
 765                         BUG();
 766                 spin_unlock_bh(&call->lock);
 767                 goto process_further;
 768         }
 769
 770 discard:
 771         rxrpc_free_skb(skb);
 772         goto process_further;
 773
 774 protocol_error_unlock:
 775         write_unlock_bh(&call->state_lock);
 776 protocol_error:
 777         rxrpc_free_skb(skb);
 778         _leave(" = -EPROTO");
 779         return -EPROTO;
 780 }
 781
 782 /*
 783  * post a message to the socket Rx queue for recvmsg() to pick up
 784  */
 785 static int rxrpc_post_message(struct rxrpc_call *call, u32 mark, u32 error,
 786                               bool fatal)
 787 {
 788         struct rxrpc_skb_priv *sp;
 789         struct sk_buff *skb;
 790         int ret;
 791
 792         _enter("{%d,%lx},%u,%u,%d",
 793                call->debug_id, call->flags, mark, error, fatal);
 794
 795         /* remove timers and things for fatal messages */
 796         if (fatal) {
 797                 del_timer_sync(&call->resend_timer);
 798                 del_timer_sync(&call->ack_timer);
 799                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 800         }
 801
 802         if (mark != RXRPC_SKB_MARK_NEW_CALL &&
 803             !test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
 804                 _leave("[no userid]");
 805                 return 0;
 806         }
 807
 808         if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
 809                 skb = alloc_skb(0, GFP_NOFS);
 810                 if (!skb)
 811                         return -ENOMEM;
 812
 813                 rxrpc_new_skb(skb);
 814
 815                 skb->mark = mark;
 816
 817                 sp = rxrpc_skb(skb);
 818                 memset(sp, 0, sizeof(*sp));
 819                 sp->error = error;
 820                 sp->call = call;
 821                 rxrpc_get_call(call);
 822
 823                 spin_lock_bh(&call->lock);
 824                 ret = rxrpc_queue_rcv_skb(call, skb, true, fatal);
 825                 spin_unlock_bh(&call->lock);
 826                 BUG_ON(ret < 0);
 827         }
 828
 829         return 0;
 830 }
 831
 832 /*
 833  * handle background processing of incoming call packets and ACK / abort
 834  * generation
 835  */
 836 void rxrpc_process_call(struct work_struct *work)
 837 {
 838         struct rxrpc_call *call =
 839                 container_of(work, struct rxrpc_call, processor);
 840         struct rxrpc_ackpacket ack;
 841         struct rxrpc_ackinfo ackinfo;
 842         struct rxrpc_header hdr;
 843         struct msghdr msg;
 844         struct kvec iov[5];
 845         unsigned long bits;
 846         __be32 data, pad;
 847         size_t len;
 848         int genbit, loop, nbit, ioc, ret, mtu;
 849         u32 abort_code = RX_PROTOCOL_ERROR;
 850         u8 *acks = NULL;
 851
 852         //printk("\n--------------------\n");
 853         _enter("{%d,%s,%lx} [%lu]",
 854                call->debug_id, rxrpc_call_states[call->state], call->events,
 855                (jiffies - call->creation_jif) / (HZ / 10));
 856
 857         if (test_and_set_bit(RXRPC_CALL_PROC_BUSY, &call->flags)) {
 858                 _debug("XXXXXXXXXXXXX RUNNING ON MULTIPLE CPUS XXXXXXXXXXXXX");
 859                 return;
 860         }
 861
 862         /* there's a good chance we're going to have to send a message, so set
 863          * one up in advance */
 864         msg.msg_name    = &call->conn->trans->peer->srx.transport.sin;
 865         msg.msg_namelen = sizeof(call->conn->trans->peer->srx.transport.sin);
 866         msg.msg_control = NULL;
 867         msg.msg_controllen = 0;
 868         msg.msg_flags   = 0;
 869
 870         hdr.epoch       = call->conn->epoch;
 871         hdr.cid         = call->cid;
 872         hdr.callNumber  = call->call_id;
 873         hdr.seq         = 0;
 874         hdr.type        = RXRPC_PACKET_TYPE_ACK;
 875         hdr.flags       = call->conn->out_clientflag;
 876         hdr.userStatus  = 0;
 877         hdr.securityIndex = call->conn->security_ix;
 878         hdr._rsvd       = 0;
 879         hdr.serviceId   = call->conn->service_id;
 880
 881         memset(iov, 0, sizeof(iov));
 882         iov[0].iov_base = &hdr;
 883         iov[0].iov_len  = sizeof(hdr);
 884
 885         /* deal with events of a final nature */
 886         if (test_bit(RXRPC_CALL_RELEASE, &call->events)) {
 887                 rxrpc_release_call(call);
 888                 clear_bit(RXRPC_CALL_RELEASE, &call->events);
 889         }
 890
 891         if (test_bit(RXRPC_CALL_RCVD_ERROR, &call->events)) {
 892                 int error;
 893
 894                 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
 895                 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
 896                 clear_bit(RXRPC_CALL_ABORT, &call->events);
 897
 898                 error = call->conn->trans->peer->net_error;
 899                 _debug("post net error %d", error);
 900
 901                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NET_ERROR,
 902                                        error, true) < 0)
 903                         goto no_mem;
 904                 clear_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
 905                 goto kill_ACKs;
 906         }
 907
 908         if (test_bit(RXRPC_CALL_CONN_ABORT, &call->events)) {
 909                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
 910
 911                 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
 912                 clear_bit(RXRPC_CALL_ABORT, &call->events);
 913
 914                 _debug("post conn abort");
 915
 916                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 917                                        call->conn->error, true) < 0)
 918                         goto no_mem;
 919                 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
 920                 goto kill_ACKs;
 921         }
 922
 923         if (test_bit(RXRPC_CALL_REJECT_BUSY, &call->events)) {
 924                 hdr.type = RXRPC_PACKET_TYPE_BUSY;
 925                 genbit = RXRPC_CALL_REJECT_BUSY;
 926                 goto send_message;
 927         }
 928
 929         if (test_bit(RXRPC_CALL_ABORT, &call->events)) {
 930                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
 931
 932                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 933                                        ECONNABORTED, true) < 0)
 934                         goto no_mem;
 935                 hdr.type = RXRPC_PACKET_TYPE_ABORT;
 936                 data = htonl(call->abort_code);
 937                 iov[1].iov_base = &data;
 938                 iov[1].iov_len = sizeof(data);
 939                 genbit = RXRPC_CALL_ABORT;
 940                 goto send_message;
 941         }
 942
 943         if (test_bit(RXRPC_CALL_ACK_FINAL, &call->events)) {
 944                 genbit = RXRPC_CALL_ACK_FINAL;
 945
 946                 ack.bufferSpace = htons(8);
 947                 ack.maxSkew     = 0;
 948                 ack.serial      = 0;
 949                 ack.reason      = RXRPC_ACK_IDLE;
 950                 ack.nAcks       = 0;
 951                 call->ackr_reason = 0;
 952
 953                 spin_lock_bh(&call->lock);
 954                 ack.serial = call->ackr_serial;
 955                 ack.previousPacket = call->ackr_prev_seq;
 956                 ack.firstPacket = htonl(call->rx_data_eaten + 1);
 957                 spin_unlock_bh(&call->lock);
 958
 959                 pad = 0;
 960
 961                 iov[1].iov_base = &ack;
 962                 iov[1].iov_len  = sizeof(ack);
 963                 iov[2].iov_base = &pad;
 964                 iov[2].iov_len  = 3;
 965                 iov[3].iov_base = &ackinfo;
 966                 iov[3].iov_len  = sizeof(ackinfo);
 967                 goto send_ACK;
 968         }
 969
 970         if (call->events & ((1 << RXRPC_CALL_RCVD_BUSY) |
 971                             (1 << RXRPC_CALL_RCVD_ABORT))
 972             ) {
 973                 u32 mark;
 974
 975                 if (test_bit(RXRPC_CALL_RCVD_ABORT, &call->events))
 976                         mark = RXRPC_SKB_MARK_REMOTE_ABORT;
 977                 else
 978                         mark = RXRPC_SKB_MARK_BUSY;
 979
 980                 _debug("post abort/busy");
 981                 rxrpc_clear_tx_window(call);
 982                 if (rxrpc_post_message(call, mark, ECONNABORTED, true) < 0)
 983                         goto no_mem;
 984
 985                 clear_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
 986                 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
 987                 goto kill_ACKs;
 988         }
 989
 990         if (test_and_clear_bit(RXRPC_CALL_RCVD_ACKALL, &call->events)) {
 991                 _debug("do implicit ackall");
 992                 rxrpc_clear_tx_window(call);
 993         }
 994
 995         if (test_bit(RXRPC_CALL_LIFE_TIMER, &call->events)) {
 996                 write_lock_bh(&call->state_lock);
 997                 if (call->state <= RXRPC_CALL_COMPLETE) {
 998                         call->state = RXRPC_CALL_LOCALLY_ABORTED;
 999                         call->abort_code = RX_CALL_TIMEOUT;
1000                         set_bit(RXRPC_CALL_ABORT, &call->events);
1001                 }
1002                 write_unlock_bh(&call->state_lock);
1003
1004                 _debug("post timeout");
1005                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
1006                                        ETIME, true) < 0)
1007                         goto no_mem;
1008
1009                 clear_bit(RXRPC_CALL_LIFE_TIMER, &call->events);
1010                 goto kill_ACKs;
1011         }
1012
1013         /* deal with assorted inbound messages */
1014         if (!skb_queue_empty(&call->rx_queue)) {
1015                 switch (rxrpc_process_rx_queue(call, &abort_code)) {
1016                 case 0:
1017                 case -EAGAIN:
1018                         break;
1019                 case -ENOMEM:
1020                         goto no_mem;
1021                 case -EKEYEXPIRED:
1022                 case -EKEYREJECTED:
1023                 case -EPROTO:
1024                         rxrpc_abort_call(call, abort_code);
1025                         goto kill_ACKs;
1026                 }
1027         }
1028
1029         /* handle resending */
1030         if (test_and_clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
1031                 rxrpc_resend_timer(call);
1032         if (test_and_clear_bit(RXRPC_CALL_RESEND, &call->events))
1033                 rxrpc_resend(call);
1034
1035         /* consider sending an ordinary ACK */
1036         if (test_bit(RXRPC_CALL_ACK, &call->events)) {
1037                 _debug("send ACK: window: %d - %d { %lx }",
1038                        call->rx_data_eaten, call->ackr_win_top,
1039                        call->ackr_window[0]);
1040
1041                 if (call->state > RXRPC_CALL_SERVER_ACK_REQUEST &&
1042                     call->ackr_reason != RXRPC_ACK_PING_RESPONSE) {
1043                         /* ACK by sending reply DATA packet in this state */
1044                         clear_bit(RXRPC_CALL_ACK, &call->events);
1045                         goto maybe_reschedule;
1046                 }
1047
1048                 genbit = RXRPC_CALL_ACK;
1049
1050                 acks = kzalloc(call->ackr_win_top - call->rx_data_eaten,
1051                                GFP_NOFS);
1052                 if (!acks)
1053                         goto no_mem;
1054
1055                 //hdr.flags     = RXRPC_SLOW_START_OK;
1056                 ack.bufferSpace = htons(8);
1057                 ack.maxSkew     = 0;
1058                 ack.serial      = 0;
1059                 ack.reason      = 0;
1060
1061                 spin_lock_bh(&call->lock);
1062                 ack.reason = call->ackr_reason;
1063                 ack.serial = call->ackr_serial;
1064                 ack.previousPacket = call->ackr_prev_seq;
1065                 ack.firstPacket = htonl(call->rx_data_eaten + 1);
1066
1067                 ack.nAcks = 0;
1068                 for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
1069                         nbit = loop * BITS_PER_LONG;
1070                         for (bits = call->ackr_window[loop]; bits; bits >>= 1
1071                              ) {
1072                                 _debug("- l=%d n=%d b=%lx", loop, nbit, bits);
1073                                 if (bits & 1) {
1074                                         acks[nbit] = RXRPC_ACK_TYPE_ACK;
1075                                         ack.nAcks = nbit + 1;
1076                                 }
1077                                 nbit++;
1078                         }
1079                 }
1080                 call->ackr_reason = 0;
1081                 spin_unlock_bh(&call->lock);
1082
1083                 pad = 0;
1084
1085                 iov[1].iov_base = &ack;
1086                 iov[1].iov_len  = sizeof(ack);
1087                 iov[2].iov_base = acks;
1088                 iov[2].iov_len  = ack.nAcks;
1089                 iov[3].iov_base = &pad;
1090                 iov[3].iov_len  = 3;
1091                 iov[4].iov_base = &ackinfo;
1092                 iov[4].iov_len  = sizeof(ackinfo);
1093
1094                 switch (ack.reason) {
1095                 case RXRPC_ACK_REQUESTED:
1096                 case RXRPC_ACK_DUPLICATE:
1097                 case RXRPC_ACK_OUT_OF_SEQUENCE:
1098                 case RXRPC_ACK_EXCEEDS_WINDOW:
1099                 case RXRPC_ACK_NOSPACE:
1100                 case RXRPC_ACK_PING:
1101                 case RXRPC_ACK_PING_RESPONSE:
1102                         goto send_ACK_with_skew;
1103                 case RXRPC_ACK_DELAY:
1104                 case RXRPC_ACK_IDLE:
1105                         goto send_ACK;
1106                 }
1107         }
1108
1109         /* handle completion of security negotiations on an incoming
1110          * connection */
1111         if (test_and_clear_bit(RXRPC_CALL_SECURED, &call->events)) {
1112                 _debug("secured");
1113                 spin_lock_bh(&call->lock);
1114
1115                 if (call->state == RXRPC_CALL_SERVER_SECURING) {
1116                         _debug("securing");
1117                         write_lock(&call->conn->lock);
1118                         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1119                             !test_bit(RXRPC_CALL_RELEASE, &call->events)) {
1120                                 _debug("not released");
1121                                 call->state = RXRPC_CALL_SERVER_ACCEPTING;
1122                                 list_move_tail(&call->accept_link,
1123                                                &call->socket->acceptq);
1124                         }
1125                         write_unlock(&call->conn->lock);
1126                         read_lock(&call->state_lock);
1127                         if (call->state < RXRPC_CALL_COMPLETE)
1128                                 set_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1129                         read_unlock(&call->state_lock);
1130                 }
1131
1132                 spin_unlock_bh(&call->lock);
1133                 if (!test_bit(RXRPC_CALL_POST_ACCEPT, &call->events))
1134                         goto maybe_reschedule;
1135         }
1136
1137         /* post a notification of an acceptable connection to the app */
1138         if (test_bit(RXRPC_CALL_POST_ACCEPT, &call->events)) {
1139                 _debug("post accept");
1140                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NEW_CALL,
1141                                        0, false) < 0)
1142                         goto no_mem;
1143                 clear_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1144                 goto maybe_reschedule;
1145         }
1146
1147         /* handle incoming call acceptance */
1148         if (test_and_clear_bit(RXRPC_CALL_ACCEPTED, &call->events)) {
1149                 _debug("accepted");
1150                 ASSERTCMP(call->rx_data_post, ==, 0);
1151                 call->rx_data_post = 1;
1152                 read_lock_bh(&call->state_lock);
1153                 if (call->state < RXRPC_CALL_COMPLETE)
1154                         set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
1155                 read_unlock_bh(&call->state_lock);
1156         }
1157
1158         /* drain the out of sequence received packet queue into the packet Rx
1159          * queue */
1160         if (test_and_clear_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events)) {
1161                 while (call->rx_data_post == call->rx_first_oos)
1162                         if (rxrpc_drain_rx_oos_queue(call) < 0)
1163                                 break;
1164                 goto maybe_reschedule;
1165         }
1166
1167         /* other events may have been raised since we started checking */
1168         goto maybe_reschedule;
1169
1170 send_ACK_with_skew:
1171         ack.maxSkew = htons(atomic_read(&call->conn->hi_serial) -
1172                             ntohl(ack.serial));
1173 send_ACK:
1174         mtu = call->conn->trans->peer->if_mtu;
1175         mtu -= call->conn->trans->peer->hdrsize;
1176         ackinfo.maxMTU  = htonl(mtu);
1177         ackinfo.rwind   = htonl(32);
1178
1179         /* permit the peer to send us jumbo packets if it wants to */
1180         ackinfo.rxMTU   = htonl(5692);
1181         ackinfo.jumbo_max = htonl(4);
1182
1183         hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1184         _proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
1185                ntohl(hdr.serial),
1186                ntohs(ack.maxSkew),
1187                ntohl(ack.firstPacket),
1188                ntohl(ack.previousPacket),
1189                ntohl(ack.serial),
1190                rxrpc_acks(ack.reason),
1191                ack.nAcks);
1192
1193         del_timer_sync(&call->ack_timer);
1194         if (ack.nAcks > 0)
1195                 set_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags);
1196         goto send_message_2;
1197
1198 send_message:
1199         _debug("send message");
1200
1201         hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1202         _proto("Tx %s %%%u", rxrpc_pkts[hdr.type], ntohl(hdr.serial));
1203 send_message_2:
1204
1205         len = iov[0].iov_len;
1206         ioc = 1;
1207         if (iov[4].iov_len) {
1208                 ioc = 5;
1209                 len += iov[4].iov_len;
1210                 len += iov[3].iov_len;
1211                 len += iov[2].iov_len;
1212                 len += iov[1].iov_len;
1213         } else if (iov[3].iov_len) {
1214                 ioc = 4;
1215                 len += iov[3].iov_len;
1216                 len += iov[2].iov_len;
1217                 len += iov[1].iov_len;
1218         } else if (iov[2].iov_len) {
1219                 ioc = 3;
1220                 len += iov[2].iov_len;
1221                 len += iov[1].iov_len;
1222         } else if (iov[1].iov_len) {
1223                 ioc = 2;
1224                 len += iov[1].iov_len;
1225         }
1226
1227         ret = kernel_sendmsg(call->conn->trans->local->socket,
1228                              &msg, iov, ioc, len);
1229         if (ret < 0) {
1230                 _debug("sendmsg failed: %d", ret);
1231                 read_lock_bh(&call->state_lock);
1232                 if (call->state < RXRPC_CALL_DEAD)
1233                         rxrpc_queue_call(call);
1234                 read_unlock_bh(&call->state_lock);
1235                 goto error;
1236         }
1237
1238         switch (genbit) {
1239         case RXRPC_CALL_ABORT:
1240                 clear_bit(genbit, &call->events);
1241                 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
1242                 goto kill_ACKs;
1243
1244         case RXRPC_CALL_ACK_FINAL:
1245                 write_lock_bh(&call->state_lock);
1246                 if (call->state == RXRPC_CALL_CLIENT_FINAL_ACK)
1247                         call->state = RXRPC_CALL_COMPLETE;
1248                 write_unlock_bh(&call->state_lock);
1249                 goto kill_ACKs;
1250
1251         default:
1252                 clear_bit(genbit, &call->events);
1253                 switch (call->state) {
1254                 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
1255                 case RXRPC_CALL_CLIENT_RECV_REPLY:
1256                 case RXRPC_CALL_SERVER_RECV_REQUEST:
1257                 case RXRPC_CALL_SERVER_ACK_REQUEST:
1258                         _debug("start ACK timer");
1259                         rxrpc_propose_ACK(call, RXRPC_ACK_DELAY,
1260                                           call->ackr_serial, false);
1261                 default:
1262                         break;
1263                 }
1264                 goto maybe_reschedule;
1265         }
1266
1267 kill_ACKs:
1268         del_timer_sync(&call->ack_timer);
1269         if (test_and_clear_bit(RXRPC_CALL_ACK_FINAL, &call->events))
1270                 rxrpc_put_call(call);
1271         clear_bit(RXRPC_CALL_ACK, &call->events);
1272
1273 maybe_reschedule:
1274         if (call->events || !skb_queue_empty(&call->rx_queue)) {
1275                 read_lock_bh(&call->state_lock);
1276                 if (call->state < RXRPC_CALL_DEAD)
1277                         rxrpc_queue_call(call);
1278                 read_unlock_bh(&call->state_lock);
1279         }
1280
1281         /* don't leave aborted connections on the accept queue */
1282         if (call->state >= RXRPC_CALL_COMPLETE &&
1283             !list_empty(&call->accept_link)) {
1284                 _debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
1285                        call, call->events, call->flags,
1286                        ntohl(call->conn->cid));
1287
1288                 read_lock_bh(&call->state_lock);
1289                 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1290                     !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
1291                         rxrpc_queue_call(call);
1292                 read_unlock_bh(&call->state_lock);
1293         }
1294
1295 error:
1296         clear_bit(RXRPC_CALL_PROC_BUSY, &call->flags);
1297         kfree(acks);
1298
1299         /* because we don't want two CPUs both processing the work item for one
1300          * call at the same time, we use a flag to note when it's busy; however
1301          * this means there's a race between clearing the flag and setting the
1302          * work pending bit and the work item being processed again */
1303         if (call->events && !work_pending(&call->processor)) {
1304                 _debug("jumpstart %x", ntohl(call->conn->cid));
1305                 rxrpc_queue_call(call);
1306         }
1307
1308         _leave("");
1309         return;
1310
1311 no_mem:
1312         _debug("out of memory");
1313         goto maybe_reschedule;
1314 }