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