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         unsigned long _skb;
 379         int tail = call->acks_tail, old_tail;
 380         int win = CIRC_CNT(call->acks_head, tail, call->acks_winsz);
 381
 382         _enter("{%u,%u},%u", call->acks_hard, win, hard);
 383
 384         ASSERTCMP(hard - call->acks_hard, <=, win);
 385
 386         while (call->acks_hard < hard) {
 387                 smp_read_barrier_depends();
 388                 _skb = call->acks_window[tail] & ~1;
 389                 rxrpc_free_skb((struct sk_buff *) _skb);
 390                 old_tail = tail;
 391                 tail = (tail + 1) & (call->acks_winsz - 1);
 392                 call->acks_tail = tail;
 393                 if (call->acks_unacked == old_tail)
 394                         call->acks_unacked = tail;
 395                 call->acks_hard++;
 396         }
 397
 398         wake_up(&call->tx_waitq);
 399 }
 400
 401 /*
 402  * clear the Tx window in the event of a failure
 403  */
 404 static void rxrpc_clear_tx_window(struct rxrpc_call *call)
 405 {
 406         rxrpc_rotate_tx_window(call, atomic_read(&call->sequence));
 407 }
 408
 409 /*
 410  * drain the out of sequence received packet queue into the packet Rx queue
 411  */
 412 static int rxrpc_drain_rx_oos_queue(struct rxrpc_call *call)
 413 {
 414         struct rxrpc_skb_priv *sp;
 415         struct sk_buff *skb;
 416         bool terminal;
 417         int ret;
 418
 419         _enter("{%d,%d}", call->rx_data_post, call->rx_first_oos);
 420
 421         spin_lock_bh(&call->lock);
 422
 423         ret = -ECONNRESET;
 424         if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
 425                 goto socket_unavailable;
 426
 427         skb = skb_dequeue(&call->rx_oos_queue);
 428         if (skb) {
 429                 sp = rxrpc_skb(skb);
 430
 431                 _debug("drain OOS packet %d [%d]",
 432                        ntohl(sp->hdr.seq), call->rx_first_oos);
 433
 434                 if (ntohl(sp->hdr.seq) != call->rx_first_oos) {
 435                         skb_queue_head(&call->rx_oos_queue, skb);
 436                         call->rx_first_oos = ntohl(rxrpc_skb(skb)->hdr.seq);
 437                         _debug("requeue %p {%u}", skb, call->rx_first_oos);
 438                 } else {
 439                         skb->mark = RXRPC_SKB_MARK_DATA;
 440                         terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
 441                                 !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
 442                         ret = rxrpc_queue_rcv_skb(call, skb, true, terminal);
 443                         BUG_ON(ret < 0);
 444                         _debug("drain #%u", call->rx_data_post);
 445                         call->rx_data_post++;
 446
 447                         /* find out what the next packet is */
 448                         skb = skb_peek(&call->rx_oos_queue);
 449                         if (skb)
 450                                 call->rx_first_oos =
 451                                         ntohl(rxrpc_skb(skb)->hdr.seq);
 452                         else
 453                                 call->rx_first_oos = 0;
 454                         _debug("peek %p {%u}", skb, call->rx_first_oos);
 455                 }
 456         }
 457
 458         ret = 0;
 459 socket_unavailable:
 460         spin_unlock_bh(&call->lock);
 461         _leave(" = %d", ret);
 462         return ret;
 463 }
 464
 465 /*
 466  * insert an out of sequence packet into the buffer
 467  */
 468 static void rxrpc_insert_oos_packet(struct rxrpc_call *call,
 469                                     struct sk_buff *skb)
 470 {
 471         struct rxrpc_skb_priv *sp, *psp;
 472         struct sk_buff *p;
 473         u32 seq;
 474
 475         sp = rxrpc_skb(skb);
 476         seq = ntohl(sp->hdr.seq);
 477         _enter(",,{%u}", seq);
 478
 479         skb->destructor = rxrpc_packet_destructor;
 480         ASSERTCMP(sp->call, ==, NULL);
 481         sp->call = call;
 482         rxrpc_get_call(call);
 483
 484         /* insert into the buffer in sequence order */
 485         spin_lock_bh(&call->lock);
 486
 487         skb_queue_walk(&call->rx_oos_queue, p) {
 488                 psp = rxrpc_skb(p);
 489                 if (ntohl(psp->hdr.seq) > seq) {
 490                         _debug("insert oos #%u before #%u",
 491                                seq, ntohl(psp->hdr.seq));
 492                         skb_insert(p, skb, &call->rx_oos_queue);
 493                         goto inserted;
 494                 }
 495         }
 496
 497         _debug("append oos #%u", seq);
 498         skb_queue_tail(&call->rx_oos_queue, skb);
 499 inserted:
 500
 501         /* we might now have a new front to the queue */
 502         if (call->rx_first_oos == 0 || seq < call->rx_first_oos)
 503                 call->rx_first_oos = seq;
 504
 505         read_lock(&call->state_lock);
 506         if (call->state < RXRPC_CALL_COMPLETE &&
 507             call->rx_data_post == call->rx_first_oos) {
 508                 _debug("drain rx oos now");
 509                 set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
 510         }
 511         read_unlock(&call->state_lock);
 512
 513         spin_unlock_bh(&call->lock);
 514         _leave(" [stored #%u]", call->rx_first_oos);
 515 }
 516
 517 /*
 518  * clear the Tx window on final ACK reception
 519  */
 520 static void rxrpc_zap_tx_window(struct rxrpc_call *call)
 521 {
 522         struct rxrpc_skb_priv *sp;
 523         struct sk_buff *skb;
 524         unsigned long _skb, *acks_window;
 525         u8 winsz = call->acks_winsz;
 526         int tail;
 527
 528         acks_window = call->acks_window;
 529         call->acks_window = NULL;
 530
 531         while (CIRC_CNT(call->acks_head, call->acks_tail, winsz) > 0) {
 532                 tail = call->acks_tail;
 533                 smp_read_barrier_depends();
 534                 _skb = acks_window[tail] & ~1;
 535                 smp_mb();
 536                 call->acks_tail = (call->acks_tail + 1) & (winsz - 1);
 537
 538                 skb = (struct sk_buff *) _skb;
 539                 sp = rxrpc_skb(skb);
 540                 _debug("+++ clear Tx %u", ntohl(sp->hdr.seq));
 541                 rxrpc_free_skb(skb);
 542         }
 543
 544         kfree(acks_window);
 545 }
 546
 547 /*
 548  * process the extra information that may be appended to an ACK packet
 549  */
 550 static void rxrpc_extract_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 551                                   unsigned latest, int nAcks)
 552 {
 553         struct rxrpc_ackinfo ackinfo;
 554         struct rxrpc_peer *peer;
 555         unsigned mtu;
 556
 557         if (skb_copy_bits(skb, nAcks + 3, &ackinfo, sizeof(ackinfo)) < 0) {
 558                 _leave(" [no ackinfo]");
 559                 return;
 560         }
 561
 562         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 563                latest,
 564                ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU),
 565                ntohl(ackinfo.rwind), ntohl(ackinfo.jumbo_max));
 566
 567         mtu = min(ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU));
 568
 569         peer = call->conn->trans->peer;
 570         if (mtu < peer->maxdata) {
 571                 spin_lock_bh(&peer->lock);
 572                 peer->maxdata = mtu;
 573                 peer->mtu = mtu + peer->hdrsize;
 574                 spin_unlock_bh(&peer->lock);
 575                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 576         }
 577 }
 578
 579 /*
 580  * process packets in the reception queue
 581  */
 582 static int rxrpc_process_rx_queue(struct rxrpc_call *call,
 583                                   u32 *_abort_code)
 584 {
 585         struct rxrpc_ackpacket ack;
 586         struct rxrpc_skb_priv *sp;
 587         struct sk_buff *skb;
 588         bool post_ACK;
 589         int latest;
 590         u32 hard, tx;
 591
 592         _enter("");
 593
 594 process_further:
 595         skb = skb_dequeue(&call->rx_queue);
 596         if (!skb)
 597                 return -EAGAIN;
 598
 599         _net("deferred skb %p", skb);
 600
 601         sp = rxrpc_skb(skb);
 602
 603         _debug("process %s [st %d]", rxrpc_pkts[sp->hdr.type], call->state);
 604
 605         post_ACK = false;
 606
 607         switch (sp->hdr.type) {
 608                 /* data packets that wind up here have been received out of
 609                  * order, need security processing or are jumbo packets */
 610         case RXRPC_PACKET_TYPE_DATA:
 611                 _proto("OOSQ DATA %%%u { #%u }",
 612                        ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
 613
 614                 /* secured packets must be verified and possibly decrypted */
 615                 if (rxrpc_verify_packet(call, skb, _abort_code) < 0)
 616                         goto protocol_error;
 617
 618                 rxrpc_insert_oos_packet(call, skb);
 619                 goto process_further;
 620
 621                 /* partial ACK to process */
 622         case RXRPC_PACKET_TYPE_ACK:
 623                 if (skb_copy_bits(skb, 0, &ack, sizeof(ack)) < 0) {
 624                         _debug("extraction failure");
 625                         goto protocol_error;
 626                 }
 627                 if (!skb_pull(skb, sizeof(ack)))
 628                         BUG();
 629
 630                 latest = ntohl(sp->hdr.serial);
 631                 hard = ntohl(ack.firstPacket);
 632                 tx = atomic_read(&call->sequence);
 633
 634                 _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 635                        latest,
 636                        ntohs(ack.maxSkew),
 637                        hard,
 638                        ntohl(ack.previousPacket),
 639                        ntohl(ack.serial),
 640                        rxrpc_acks[ack.reason],
 641                        ack.nAcks);
 642
 643                 rxrpc_extract_ackinfo(call, skb, latest, ack.nAcks);
 644
 645                 if (ack.reason == RXRPC_ACK_PING) {
 646                         _proto("Rx ACK %%%u PING Request", latest);
 647                         rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 648                                           sp->hdr.serial, true);
 649                 }
 650
 651                 /* discard any out-of-order or duplicate ACKs */
 652                 if (latest - call->acks_latest <= 0) {
 653                         _debug("discard ACK %d <= %d",
 654                                latest, call->acks_latest);
 655                         goto discard;
 656                 }
 657                 call->acks_latest = latest;
 658
 659                 if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
 660                     call->state != RXRPC_CALL_CLIENT_AWAIT_REPLY &&
 661                     call->state != RXRPC_CALL_SERVER_SEND_REPLY &&
 662                     call->state != RXRPC_CALL_SERVER_AWAIT_ACK)
 663                         goto discard;
 664
 665                 _debug("Tx=%d H=%u S=%d", tx, call->acks_hard, call->state);
 666
 667                 if (hard > 0) {
 668                         if (hard - 1 > tx) {
 669                                 _debug("hard-ACK'd packet %d not transmitted"
 670                                        " (%d top)",
 671                                        hard - 1, tx);
 672                                 goto protocol_error;
 673                         }
 674
 675                         if ((call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY ||
 676                              call->state == RXRPC_CALL_SERVER_AWAIT_ACK) &&
 677                             hard > tx)
 678                                 goto all_acked;
 679
 680                         smp_rmb();
 681                         rxrpc_rotate_tx_window(call, hard - 1);
 682                 }
 683
 684                 if (ack.nAcks > 0) {
 685                         if (hard - 1 + ack.nAcks > tx) {
 686                                 _debug("soft-ACK'd packet %d+%d not"
 687                                        " transmitted (%d top)",
 688                                        hard - 1, ack.nAcks, tx);
 689                                 goto protocol_error;
 690                         }
 691
 692                         if (rxrpc_process_soft_ACKs(call, &ack, skb) < 0)
 693                                 goto protocol_error;
 694                 }
 695                 goto discard;
 696
 697                 /* complete ACK to process */
 698         case RXRPC_PACKET_TYPE_ACKALL:
 699                 goto all_acked;
 700
 701                 /* abort and busy are handled elsewhere */
 702         case RXRPC_PACKET_TYPE_BUSY:
 703         case RXRPC_PACKET_TYPE_ABORT:
 704                 BUG();
 705
 706                 /* connection level events - also handled elsewhere */
 707         case RXRPC_PACKET_TYPE_CHALLENGE:
 708         case RXRPC_PACKET_TYPE_RESPONSE:
 709         case RXRPC_PACKET_TYPE_DEBUG:
 710                 BUG();
 711         }
 712
 713         /* if we've had a hard ACK that covers all the packets we've sent, then
 714          * that ends that phase of the operation */
 715 all_acked:
 716         write_lock_bh(&call->state_lock);
 717         _debug("ack all %d", call->state);
 718
 719         switch (call->state) {
 720         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 721                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 722                 break;
 723         case RXRPC_CALL_SERVER_AWAIT_ACK:
 724                 _debug("srv complete");
 725                 call->state = RXRPC_CALL_COMPLETE;
 726                 post_ACK = true;
 727                 break;
 728         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 729         case RXRPC_CALL_SERVER_RECV_REQUEST:
 730                 goto protocol_error_unlock; /* can't occur yet */
 731         default:
 732                 write_unlock_bh(&call->state_lock);
 733                 goto discard; /* assume packet left over from earlier phase */
 734         }
 735
 736         write_unlock_bh(&call->state_lock);
 737
 738         /* if all the packets we sent are hard-ACK'd, then we can discard
 739          * whatever we've got left */
 740         _debug("clear Tx %d",
 741                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
 742
 743         del_timer_sync(&call->resend_timer);
 744         clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 745         clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 746
 747         if (call->acks_window)
 748                 rxrpc_zap_tx_window(call);
 749
 750         if (post_ACK) {
 751                 /* post the final ACK message for userspace to pick up */
 752                 _debug("post ACK");
 753                 skb->mark = RXRPC_SKB_MARK_FINAL_ACK;
 754                 sp->call = call;
 755                 rxrpc_get_call(call);
 756                 spin_lock_bh(&call->lock);
 757                 if (rxrpc_queue_rcv_skb(call, skb, true, true) < 0)
 758                         BUG();
 759                 spin_unlock_bh(&call->lock);
 760                 goto process_further;
 761         }
 762
 763 discard:
 764         rxrpc_free_skb(skb);
 765         goto process_further;
 766
 767 protocol_error_unlock:
 768         write_unlock_bh(&call->state_lock);
 769 protocol_error:
 770         rxrpc_free_skb(skb);
 771         _leave(" = -EPROTO");
 772         return -EPROTO;
 773 }
 774
 775 /*
 776  * post a message to the socket Rx queue for recvmsg() to pick up
 777  */
 778 static int rxrpc_post_message(struct rxrpc_call *call, u32 mark, u32 error,
 779                               bool fatal)
 780 {
 781         struct rxrpc_skb_priv *sp;
 782         struct sk_buff *skb;
 783         int ret;
 784
 785         _enter("{%d,%lx},%u,%u,%d",
 786                call->debug_id, call->flags, mark, error, fatal);
 787
 788         /* remove timers and things for fatal messages */
 789         if (fatal) {
 790                 del_timer_sync(&call->resend_timer);
 791                 del_timer_sync(&call->ack_timer);
 792                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 793         }
 794
 795         if (mark != RXRPC_SKB_MARK_NEW_CALL &&
 796             !test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
 797                 _leave("[no userid]");
 798                 return 0;
 799         }
 800
 801         if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
 802                 skb = alloc_skb(0, GFP_NOFS);
 803                 if (!skb)
 804                         return -ENOMEM;
 805
 806                 rxrpc_new_skb(skb);
 807
 808                 skb->mark = mark;
 809
 810                 sp = rxrpc_skb(skb);
 811                 memset(sp, 0, sizeof(*sp));
 812                 sp->error = error;
 813                 sp->call = call;
 814                 rxrpc_get_call(call);
 815
 816                 spin_lock_bh(&call->lock);
 817                 ret = rxrpc_queue_rcv_skb(call, skb, true, fatal);
 818                 spin_unlock_bh(&call->lock);
 819                 BUG_ON(ret < 0);
 820         }
 821
 822         return 0;
 823 }
 824
 825 /*
 826  * handle background processing of incoming call packets and ACK / abort
 827  * generation
 828  */
 829 void rxrpc_process_call(struct work_struct *work)
 830 {
 831         struct rxrpc_call *call =
 832                 container_of(work, struct rxrpc_call, processor);
 833         struct rxrpc_ackpacket ack;
 834         struct rxrpc_ackinfo ackinfo;
 835         struct rxrpc_header hdr;
 836         struct msghdr msg;
 837         struct kvec iov[5];
 838         unsigned long bits;
 839         __be32 data, pad;
 840         size_t len;
 841         int genbit, loop, nbit, ioc, ret, mtu;
 842         u32 abort_code = RX_PROTOCOL_ERROR;
 843         u8 *acks = NULL;
 844
 845         //printk("\n--------------------\n");
 846         _enter("{%d,%s,%lx} [%lu]",
 847                call->debug_id, rxrpc_call_states[call->state], call->events,
 848                (jiffies - call->creation_jif) / (HZ / 10));
 849
 850         if (test_and_set_bit(RXRPC_CALL_PROC_BUSY, &call->flags)) {
 851                 _debug("XXXXXXXXXXXXX RUNNING ON MULTIPLE CPUS XXXXXXXXXXXXX");
 852                 return;
 853         }
 854
 855         /* there's a good chance we're going to have to send a message, so set
 856          * one up in advance */
 857         msg.msg_name    = &call->conn->trans->peer->srx.transport.sin;
 858         msg.msg_namelen = sizeof(call->conn->trans->peer->srx.transport.sin);
 859         msg.msg_control = NULL;
 860         msg.msg_controllen = 0;
 861         msg.msg_flags   = 0;
 862
 863         hdr.epoch       = call->conn->epoch;
 864         hdr.cid         = call->cid;
 865         hdr.callNumber  = call->call_id;
 866         hdr.seq         = 0;
 867         hdr.type        = RXRPC_PACKET_TYPE_ACK;
 868         hdr.flags       = call->conn->out_clientflag;
 869         hdr.userStatus  = 0;
 870         hdr.securityIndex = call->conn->security_ix;
 871         hdr._rsvd       = 0;
 872         hdr.serviceId   = call->conn->service_id;
 873
 874         memset(iov, 0, sizeof(iov));
 875         iov[0].iov_base = &hdr;
 876         iov[0].iov_len  = sizeof(hdr);
 877
 878         /* deal with events of a final nature */
 879         if (test_bit(RXRPC_CALL_RELEASE, &call->events)) {
 880                 rxrpc_release_call(call);
 881                 clear_bit(RXRPC_CALL_RELEASE, &call->events);
 882         }
 883
 884         if (test_bit(RXRPC_CALL_RCVD_ERROR, &call->events)) {
 885                 int error;
 886
 887                 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
 888                 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
 889                 clear_bit(RXRPC_CALL_ABORT, &call->events);
 890
 891                 error = call->conn->trans->peer->net_error;
 892                 _debug("post net error %d", error);
 893
 894                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NET_ERROR,
 895                                        error, true) < 0)
 896                         goto no_mem;
 897                 clear_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
 898                 goto kill_ACKs;
 899         }
 900
 901         if (test_bit(RXRPC_CALL_CONN_ABORT, &call->events)) {
 902                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
 903
 904                 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
 905                 clear_bit(RXRPC_CALL_ABORT, &call->events);
 906
 907                 _debug("post conn abort");
 908
 909                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 910                                        call->conn->error, true) < 0)
 911                         goto no_mem;
 912                 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
 913                 goto kill_ACKs;
 914         }
 915
 916         if (test_bit(RXRPC_CALL_REJECT_BUSY, &call->events)) {
 917                 hdr.type = RXRPC_PACKET_TYPE_BUSY;
 918                 genbit = RXRPC_CALL_REJECT_BUSY;
 919                 goto send_message;
 920         }
 921
 922         if (test_bit(RXRPC_CALL_ABORT, &call->events)) {
 923                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
 924
 925                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 926                                        ECONNABORTED, true) < 0)
 927                         goto no_mem;
 928                 hdr.type = RXRPC_PACKET_TYPE_ABORT;
 929                 data = htonl(call->abort_code);
 930                 iov[1].iov_base = &data;
 931                 iov[1].iov_len = sizeof(data);
 932                 genbit = RXRPC_CALL_ABORT;
 933                 goto send_message;
 934         }
 935
 936         if (test_bit(RXRPC_CALL_ACK_FINAL, &call->events)) {
 937                 genbit = RXRPC_CALL_ACK_FINAL;
 938
 939                 ack.bufferSpace = htons(8);
 940                 ack.maxSkew     = 0;
 941                 ack.serial      = 0;
 942                 ack.reason      = RXRPC_ACK_IDLE;
 943                 ack.nAcks       = 0;
 944                 call->ackr_reason = 0;
 945
 946                 spin_lock_bh(&call->lock);
 947                 ack.serial = call->ackr_serial;
 948                 ack.previousPacket = call->ackr_prev_seq;
 949                 ack.firstPacket = htonl(call->rx_data_eaten + 1);
 950                 spin_unlock_bh(&call->lock);
 951
 952                 pad = 0;
 953
 954                 iov[1].iov_base = &ack;
 955                 iov[1].iov_len  = sizeof(ack);
 956                 iov[2].iov_base = &pad;
 957                 iov[2].iov_len  = 3;
 958                 iov[3].iov_base = &ackinfo;
 959                 iov[3].iov_len  = sizeof(ackinfo);
 960                 goto send_ACK;
 961         }
 962
 963         if (call->events & ((1 << RXRPC_CALL_RCVD_BUSY) |
 964                             (1 << RXRPC_CALL_RCVD_ABORT))
 965             ) {
 966                 u32 mark;
 967
 968                 if (test_bit(RXRPC_CALL_RCVD_ABORT, &call->events))
 969                         mark = RXRPC_SKB_MARK_REMOTE_ABORT;
 970                 else
 971                         mark = RXRPC_SKB_MARK_BUSY;
 972
 973                 _debug("post abort/busy");
 974                 rxrpc_clear_tx_window(call);
 975                 if (rxrpc_post_message(call, mark, ECONNABORTED, true) < 0)
 976                         goto no_mem;
 977
 978                 clear_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
 979                 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
 980                 goto kill_ACKs;
 981         }
 982
 983         if (test_and_clear_bit(RXRPC_CALL_RCVD_ACKALL, &call->events)) {
 984                 _debug("do implicit ackall");
 985                 rxrpc_clear_tx_window(call);
 986         }
 987
 988         if (test_bit(RXRPC_CALL_LIFE_TIMER, &call->events)) {
 989                 write_lock_bh(&call->state_lock);
 990                 if (call->state <= RXRPC_CALL_COMPLETE) {
 991                         call->state = RXRPC_CALL_LOCALLY_ABORTED;
 992                         call->abort_code = RX_CALL_TIMEOUT;
 993                         set_bit(RXRPC_CALL_ABORT, &call->events);
 994                 }
 995                 write_unlock_bh(&call->state_lock);
 996
 997                 _debug("post timeout");
 998                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 999                                        ETIME, true) < 0)
1000                         goto no_mem;
1001
1002                 clear_bit(RXRPC_CALL_LIFE_TIMER, &call->events);
1003                 goto kill_ACKs;
1004         }
1005
1006         /* deal with assorted inbound messages */
1007         if (!skb_queue_empty(&call->rx_queue)) {
1008                 switch (rxrpc_process_rx_queue(call, &abort_code)) {
1009                 case 0:
1010                 case -EAGAIN:
1011                         break;
1012                 case -ENOMEM:
1013                         goto no_mem;
1014                 case -EKEYEXPIRED:
1015                 case -EKEYREJECTED:
1016                 case -EPROTO:
1017                         rxrpc_abort_call(call, abort_code);
1018                         goto kill_ACKs;
1019                 }
1020         }
1021
1022         /* handle resending */
1023         if (test_and_clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
1024                 rxrpc_resend_timer(call);
1025         if (test_and_clear_bit(RXRPC_CALL_RESEND, &call->events))
1026                 rxrpc_resend(call);
1027
1028         /* consider sending an ordinary ACK */
1029         if (test_bit(RXRPC_CALL_ACK, &call->events)) {
1030                 _debug("send ACK: window: %d - %d { %lx }",
1031                        call->rx_data_eaten, call->ackr_win_top,
1032                        call->ackr_window[0]);
1033
1034                 if (call->state > RXRPC_CALL_SERVER_ACK_REQUEST &&
1035                     call->ackr_reason != RXRPC_ACK_PING_RESPONSE) {
1036                         /* ACK by sending reply DATA packet in this state */
1037                         clear_bit(RXRPC_CALL_ACK, &call->events);
1038                         goto maybe_reschedule;
1039                 }
1040
1041                 genbit = RXRPC_CALL_ACK;
1042
1043                 acks = kzalloc(call->ackr_win_top - call->rx_data_eaten,
1044                                GFP_NOFS);
1045                 if (!acks)
1046                         goto no_mem;
1047
1048                 //hdr.flags     = RXRPC_SLOW_START_OK;
1049                 ack.bufferSpace = htons(8);
1050                 ack.maxSkew     = 0;
1051                 ack.serial      = 0;
1052                 ack.reason      = 0;
1053
1054                 spin_lock_bh(&call->lock);
1055                 ack.reason = call->ackr_reason;
1056                 ack.serial = call->ackr_serial;
1057                 ack.previousPacket = call->ackr_prev_seq;
1058                 ack.firstPacket = htonl(call->rx_data_eaten + 1);
1059
1060                 ack.nAcks = 0;
1061                 for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
1062                         nbit = loop * BITS_PER_LONG;
1063                         for (bits = call->ackr_window[loop]; bits; bits >>= 1
1064                              ) {
1065                                 _debug("- l=%d n=%d b=%lx", loop, nbit, bits);
1066                                 if (bits & 1) {
1067                                         acks[nbit] = RXRPC_ACK_TYPE_ACK;
1068                                         ack.nAcks = nbit + 1;
1069                                 }
1070                                 nbit++;
1071                         }
1072                 }
1073                 call->ackr_reason = 0;
1074                 spin_unlock_bh(&call->lock);
1075
1076                 pad = 0;
1077
1078                 iov[1].iov_base = &ack;
1079                 iov[1].iov_len  = sizeof(ack);
1080                 iov[2].iov_base = acks;
1081                 iov[2].iov_len  = ack.nAcks;
1082                 iov[3].iov_base = &pad;
1083                 iov[3].iov_len  = 3;
1084                 iov[4].iov_base = &ackinfo;
1085                 iov[4].iov_len  = sizeof(ackinfo);
1086
1087                 switch (ack.reason) {
1088                 case RXRPC_ACK_REQUESTED:
1089                 case RXRPC_ACK_DUPLICATE:
1090                 case RXRPC_ACK_OUT_OF_SEQUENCE:
1091                 case RXRPC_ACK_EXCEEDS_WINDOW:
1092                 case RXRPC_ACK_NOSPACE:
1093                 case RXRPC_ACK_PING:
1094                 case RXRPC_ACK_PING_RESPONSE:
1095                         goto send_ACK_with_skew;
1096                 case RXRPC_ACK_DELAY:
1097                 case RXRPC_ACK_IDLE:
1098                         goto send_ACK;
1099                 }
1100         }
1101
1102         /* handle completion of security negotiations on an incoming
1103          * connection */
1104         if (test_and_clear_bit(RXRPC_CALL_SECURED, &call->events)) {
1105                 _debug("secured");
1106                 spin_lock_bh(&call->lock);
1107
1108                 if (call->state == RXRPC_CALL_SERVER_SECURING) {
1109                         _debug("securing");
1110                         write_lock(&call->conn->lock);
1111                         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1112                             !test_bit(RXRPC_CALL_RELEASE, &call->events)) {
1113                                 _debug("not released");
1114                                 call->state = RXRPC_CALL_SERVER_ACCEPTING;
1115                                 list_move_tail(&call->accept_link,
1116                                                &call->socket->acceptq);
1117                         }
1118                         write_unlock(&call->conn->lock);
1119                         read_lock(&call->state_lock);
1120                         if (call->state < RXRPC_CALL_COMPLETE)
1121                                 set_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1122                         read_unlock(&call->state_lock);
1123                 }
1124
1125                 spin_unlock_bh(&call->lock);
1126                 if (!test_bit(RXRPC_CALL_POST_ACCEPT, &call->events))
1127                         goto maybe_reschedule;
1128         }
1129
1130         /* post a notification of an acceptable connection to the app */
1131         if (test_bit(RXRPC_CALL_POST_ACCEPT, &call->events)) {
1132                 _debug("post accept");
1133                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NEW_CALL,
1134                                        0, false) < 0)
1135                         goto no_mem;
1136                 clear_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1137                 goto maybe_reschedule;
1138         }
1139
1140         /* handle incoming call acceptance */
1141         if (test_and_clear_bit(RXRPC_CALL_ACCEPTED, &call->events)) {
1142                 _debug("accepted");
1143                 ASSERTCMP(call->rx_data_post, ==, 0);
1144                 call->rx_data_post = 1;
1145                 read_lock_bh(&call->state_lock);
1146                 if (call->state < RXRPC_CALL_COMPLETE)
1147                         set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
1148                 read_unlock_bh(&call->state_lock);
1149         }
1150
1151         /* drain the out of sequence received packet queue into the packet Rx
1152          * queue */
1153         if (test_and_clear_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events)) {
1154                 while (call->rx_data_post == call->rx_first_oos)
1155                         if (rxrpc_drain_rx_oos_queue(call) < 0)
1156                                 break;
1157                 goto maybe_reschedule;
1158         }
1159
1160         /* other events may have been raised since we started checking */
1161         goto maybe_reschedule;
1162
1163 send_ACK_with_skew:
1164         ack.maxSkew = htons(atomic_read(&call->conn->hi_serial) -
1165                             ntohl(ack.serial));
1166 send_ACK:
1167         mtu = call->conn->trans->peer->if_mtu;
1168         mtu -= call->conn->trans->peer->hdrsize;
1169         ackinfo.maxMTU  = htonl(mtu);
1170         ackinfo.rwind   = htonl(32);
1171
1172         /* permit the peer to send us jumbo packets if it wants to */
1173         ackinfo.rxMTU   = htonl(5692);
1174         ackinfo.jumbo_max = htonl(4);
1175
1176         hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1177         _proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
1178                ntohl(hdr.serial),
1179                ntohs(ack.maxSkew),
1180                ntohl(ack.firstPacket),
1181                ntohl(ack.previousPacket),
1182                ntohl(ack.serial),
1183                rxrpc_acks[ack.reason],
1184                ack.nAcks);
1185
1186         del_timer_sync(&call->ack_timer);
1187         if (ack.nAcks > 0)
1188                 set_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags);
1189         goto send_message_2;
1190
1191 send_message:
1192         _debug("send message");
1193
1194         hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1195         _proto("Tx %s %%%u", rxrpc_pkts[hdr.type], ntohl(hdr.serial));
1196 send_message_2:
1197
1198         len = iov[0].iov_len;
1199         ioc = 1;
1200         if (iov[4].iov_len) {
1201                 ioc = 5;
1202                 len += iov[4].iov_len;
1203                 len += iov[3].iov_len;
1204                 len += iov[2].iov_len;
1205                 len += iov[1].iov_len;
1206         } else if (iov[3].iov_len) {
1207                 ioc = 4;
1208                 len += iov[3].iov_len;
1209                 len += iov[2].iov_len;
1210                 len += iov[1].iov_len;
1211         } else if (iov[2].iov_len) {
1212                 ioc = 3;
1213                 len += iov[2].iov_len;
1214                 len += iov[1].iov_len;
1215         } else if (iov[1].iov_len) {
1216                 ioc = 2;
1217                 len += iov[1].iov_len;
1218         }
1219
1220         ret = kernel_sendmsg(call->conn->trans->local->socket,
1221                              &msg, iov, ioc, len);
1222         if (ret < 0) {
1223                 _debug("sendmsg failed: %d", ret);
1224                 read_lock_bh(&call->state_lock);
1225                 if (call->state < RXRPC_CALL_DEAD)
1226                         rxrpc_queue_call(call);
1227                 read_unlock_bh(&call->state_lock);
1228                 goto error;
1229         }
1230
1231         switch (genbit) {
1232         case RXRPC_CALL_ABORT:
1233                 clear_bit(genbit, &call->events);
1234                 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
1235                 goto kill_ACKs;
1236
1237         case RXRPC_CALL_ACK_FINAL:
1238                 write_lock_bh(&call->state_lock);
1239                 if (call->state == RXRPC_CALL_CLIENT_FINAL_ACK)
1240                         call->state = RXRPC_CALL_COMPLETE;
1241                 write_unlock_bh(&call->state_lock);
1242                 goto kill_ACKs;
1243
1244         default:
1245                 clear_bit(genbit, &call->events);
1246                 switch (call->state) {
1247                 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
1248                 case RXRPC_CALL_CLIENT_RECV_REPLY:
1249                 case RXRPC_CALL_SERVER_RECV_REQUEST:
1250                 case RXRPC_CALL_SERVER_ACK_REQUEST:
1251                         _debug("start ACK timer");
1252                         rxrpc_propose_ACK(call, RXRPC_ACK_DELAY,
1253                                           call->ackr_serial, false);
1254                 default:
1255                         break;
1256                 }
1257                 goto maybe_reschedule;
1258         }
1259
1260 kill_ACKs:
1261         del_timer_sync(&call->ack_timer);
1262         if (test_and_clear_bit(RXRPC_CALL_ACK_FINAL, &call->events))
1263                 rxrpc_put_call(call);
1264         clear_bit(RXRPC_CALL_ACK, &call->events);
1265
1266 maybe_reschedule:
1267         if (call->events || !skb_queue_empty(&call->rx_queue)) {
1268                 read_lock_bh(&call->state_lock);
1269                 if (call->state < RXRPC_CALL_DEAD)
1270                         rxrpc_queue_call(call);
1271                 read_unlock_bh(&call->state_lock);
1272         }
1273
1274         /* don't leave aborted connections on the accept queue */
1275         if (call->state >= RXRPC_CALL_COMPLETE &&
1276             !list_empty(&call->accept_link)) {
1277                 _debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
1278                        call, call->events, call->flags,
1279                        ntohl(call->conn->cid));
1280
1281                 read_lock_bh(&call->state_lock);
1282                 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1283                     !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
1284                         rxrpc_queue_call(call);
1285                 read_unlock_bh(&call->state_lock);
1286         }
1287
1288 error:
1289         clear_bit(RXRPC_CALL_PROC_BUSY, &call->flags);
1290         kfree(acks);
1291
1292         /* because we don't want two CPUs both processing the work item for one
1293          * call at the same time, we use a flag to note when it's busy; however
1294          * this means there's a race between clearing the flag and setting the
1295          * work pending bit and the work item being processed again */
1296         if (call->events && !work_pending(&call->processor)) {
1297                 _debug("jumpstart %x", ntohl(call->conn->cid));
1298                 rxrpc_queue_call(call);
1299         }
1300
1301         _leave("");
1302         return;
1303
1304 no_mem:
1305         _debug("out of memory");
1306         goto maybe_reschedule;
1307 }