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