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 /*
  23  * How long to wait before scheduling ACK generation after seeing a
  24  * packet with RXRPC_REQUEST_ACK set (in jiffies).
  25  */
  26 unsigned rxrpc_requested_ack_delay = 1;
  27
  28 /*
  29  * How long to wait before scheduling an ACK with subtype DELAY (in jiffies).
  30  *
  31  * We use this when we've received new data packets.  If those packets aren't
  32  * all consumed within this time we will send a DELAY ACK if an ACK was not
  33  * requested to let the sender know it doesn't need to resend.
  34  */
  35 unsigned rxrpc_soft_ack_delay = 1 * HZ;
  36
  37 /*
  38  * How long to wait before scheduling an ACK with subtype IDLE (in jiffies).
  39  *
  40  * We use this when we've consumed some previously soft-ACK'd packets when
  41  * further packets aren't immediately received to decide when to send an IDLE
  42  * ACK let the other end know that it can free up its Tx buffer space.
  43  */
  44 unsigned rxrpc_idle_ack_delay = 0.5 * HZ;
  45
  46 static const char *rxrpc_acks(u8 reason)
  47 {
  48         static const char *const str[] = {
  49                 "---", "REQ", "DUP", "OOS", "WIN", "MEM", "PNG", "PNR", "DLY",
  50                 "IDL", "-?-"
  51         };
  52
  53         if (reason >= ARRAY_SIZE(str))
  54                 reason = ARRAY_SIZE(str) - 1;
  55         return str[reason];
  56 }
  57
  58 static const s8 rxrpc_ack_priority[] = {
  59         [0]                             = 0,
  60         [RXRPC_ACK_DELAY]               = 1,
  61         [RXRPC_ACK_REQUESTED]           = 2,
  62         [RXRPC_ACK_IDLE]                = 3,
  63         [RXRPC_ACK_PING_RESPONSE]       = 4,
  64         [RXRPC_ACK_DUPLICATE]           = 5,
  65         [RXRPC_ACK_OUT_OF_SEQUENCE]     = 6,
  66         [RXRPC_ACK_EXCEEDS_WINDOW]      = 7,
  67         [RXRPC_ACK_NOSPACE]             = 8,
  68 };
  69
  70 /*
  71  * propose an ACK be sent
  72  */
  73 void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
  74                          __be32 serial, bool immediate)
  75 {
  76         unsigned long expiry;
  77         s8 prior = rxrpc_ack_priority[ack_reason];
  78
  79         ASSERTCMP(prior, >, 0);
  80
  81         _enter("{%d},%s,%%%x,%u",
  82                call->debug_id, rxrpc_acks(ack_reason), ntohl(serial),
  83                immediate);
  84
  85         if (prior < rxrpc_ack_priority[call->ackr_reason]) {
  86                 if (immediate)
  87                         goto cancel_timer;
  88                 return;
  89         }
  90
  91         /* update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
  92          * numbers */
  93         if (prior == rxrpc_ack_priority[call->ackr_reason]) {
  94                 if (prior <= 4)
  95                         call->ackr_serial = serial;
  96                 if (immediate)
  97                         goto cancel_timer;
  98                 return;
  99         }
 100
 101         call->ackr_reason = ack_reason;
 102         call->ackr_serial = serial;
 103
 104         switch (ack_reason) {
 105         case RXRPC_ACK_DELAY:
 106                 _debug("run delay timer");
 107                 expiry = rxrpc_soft_ack_delay;
 108                 goto run_timer;
 109
 110         case RXRPC_ACK_IDLE:
 111                 if (!immediate) {
 112                         _debug("run defer timer");
 113                         expiry = rxrpc_idle_ack_delay;
 114                         goto run_timer;
 115                 }
 116                 goto cancel_timer;
 117
 118         case RXRPC_ACK_REQUESTED:
 119                 expiry = rxrpc_requested_ack_delay;
 120                 if (!expiry)
 121                         goto cancel_timer;
 122                 if (!immediate || serial == cpu_to_be32(1)) {
 123                         _debug("run defer timer");
 124                         goto run_timer;
 125                 }
 126
 127         default:
 128                 _debug("immediate ACK");
 129                 goto cancel_timer;
 130         }
 131
 132 run_timer:
 133         expiry += jiffies;
 134         if (!timer_pending(&call->ack_timer) ||
 135             time_after(call->ack_timer.expires, expiry))
 136                 mod_timer(&call->ack_timer, expiry);
 137         return;
 138
 139 cancel_timer:
 140         _debug("cancel timer %%%u", ntohl(serial));
 141         try_to_del_timer_sync(&call->ack_timer);
 142         read_lock_bh(&call->state_lock);
 143         if (call->state <= RXRPC_CALL_COMPLETE &&
 144             !test_and_set_bit(RXRPC_CALL_ACK, &call->events))
 145                 rxrpc_queue_call(call);
 146         read_unlock_bh(&call->state_lock);
 147 }
 148
 149 /*
 150  * propose an ACK be sent, locking the call structure
 151  */
 152 void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
 153                        __be32 serial, bool immediate)
 154 {
 155         s8 prior = rxrpc_ack_priority[ack_reason];
 156
 157         if (prior > rxrpc_ack_priority[call->ackr_reason]) {
 158                 spin_lock_bh(&call->lock);
 159                 __rxrpc_propose_ACK(call, ack_reason, serial, immediate);
 160                 spin_unlock_bh(&call->lock);
 161         }
 162 }
 163
 164 /*
 165  * set the resend timer
 166  */
 167 static void rxrpc_set_resend(struct rxrpc_call *call, u8 resend,
 168                              unsigned long resend_at)
 169 {
 170         read_lock_bh(&call->state_lock);
 171         if (call->state >= RXRPC_CALL_COMPLETE)
 172                 resend = 0;
 173
 174         if (resend & 1) {
 175                 _debug("SET RESEND");
 176                 set_bit(RXRPC_CALL_RESEND, &call->events);
 177         }
 178
 179         if (resend & 2) {
 180                 _debug("MODIFY RESEND TIMER");
 181                 set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 182                 mod_timer(&call->resend_timer, resend_at);
 183         } else {
 184                 _debug("KILL RESEND TIMER");
 185                 del_timer_sync(&call->resend_timer);
 186                 clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 187                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 188         }
 189         read_unlock_bh(&call->state_lock);
 190 }
 191
 192 /*
 193  * resend packets
 194  */
 195 static void rxrpc_resend(struct rxrpc_call *call)
 196 {
 197         struct rxrpc_skb_priv *sp;
 198         struct rxrpc_header *hdr;
 199         struct sk_buff *txb;
 200         unsigned long *p_txb, resend_at;
 201         int loop, stop;
 202         u8 resend;
 203
 204         _enter("{%d,%d,%d,%d},",
 205                call->acks_hard, call->acks_unacked,
 206                atomic_read(&call->sequence),
 207                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
 208
 209         stop = 0;
 210         resend = 0;
 211         resend_at = 0;
 212
 213         for (loop = call->acks_tail;
 214              loop != call->acks_head || stop;
 215              loop = (loop + 1) &  (call->acks_winsz - 1)
 216              ) {
 217                 p_txb = call->acks_window + loop;
 218                 smp_read_barrier_depends();
 219                 if (*p_txb & 1)
 220                         continue;
 221
 222                 txb = (struct sk_buff *) *p_txb;
 223                 sp = rxrpc_skb(txb);
 224
 225                 if (sp->need_resend) {
 226                         sp->need_resend = false;
 227
 228                         /* each Tx packet has a new serial number */
 229                         sp->hdr.serial =
 230                                 htonl(atomic_inc_return(&call->conn->serial));
 231
 232                         hdr = (struct rxrpc_header *) txb->head;
 233                         hdr->serial = sp->hdr.serial;
 234
 235                         _proto("Tx DATA %%%u { #%d }",
 236                                ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
 237                         if (rxrpc_send_packet(call->conn->trans, txb) < 0) {
 238                                 stop = 0;
 239                                 sp->resend_at = jiffies + 3;
 240                         } else {
 241                                 sp->resend_at =
 242                                         jiffies + rxrpc_resend_timeout * HZ;
 243                         }
 244                 }
 245
 246                 if (time_after_eq(jiffies + 1, sp->resend_at)) {
 247                         sp->need_resend = true;
 248                         resend |= 1;
 249                 } else if (resend & 2) {
 250                         if (time_before(sp->resend_at, resend_at))
 251                                 resend_at = sp->resend_at;
 252                 } else {
 253                         resend_at = sp->resend_at;
 254                         resend |= 2;
 255                 }
 256         }
 257
 258         rxrpc_set_resend(call, resend, resend_at);
 259         _leave("");
 260 }
 261
 262 /*
 263  * handle resend timer expiry
 264  */
 265 static void rxrpc_resend_timer(struct rxrpc_call *call)
 266 {
 267         struct rxrpc_skb_priv *sp;
 268         struct sk_buff *txb;
 269         unsigned long *p_txb, resend_at;
 270         int loop;
 271         u8 resend;
 272
 273         _enter("%d,%d,%d",
 274                call->acks_tail, call->acks_unacked, call->acks_head);
 275
 276         if (call->state >= RXRPC_CALL_COMPLETE)
 277                 return;
 278
 279         resend = 0;
 280         resend_at = 0;
 281
 282         for (loop = call->acks_unacked;
 283              loop != call->acks_head;
 284              loop = (loop + 1) &  (call->acks_winsz - 1)
 285              ) {
 286                 p_txb = call->acks_window + loop;
 287                 smp_read_barrier_depends();
 288                 txb = (struct sk_buff *) (*p_txb & ~1);
 289                 sp = rxrpc_skb(txb);
 290
 291                 ASSERT(!(*p_txb & 1));
 292
 293                 if (sp->need_resend) {
 294                         ;
 295                 } else if (time_after_eq(jiffies + 1, sp->resend_at)) {
 296                         sp->need_resend = true;
 297                         resend |= 1;
 298                 } else if (resend & 2) {
 299                         if (time_before(sp->resend_at, resend_at))
 300                                 resend_at = sp->resend_at;
 301                 } else {
 302                         resend_at = sp->resend_at;
 303                         resend |= 2;
 304                 }
 305         }
 306
 307         rxrpc_set_resend(call, resend, resend_at);
 308         _leave("");
 309 }
 310
 311 /*
 312  * process soft ACKs of our transmitted packets
 313  * - these indicate packets the peer has or has not received, but hasn't yet
 314  *   given to the consumer, and so can still be discarded and re-requested
 315  */
 316 static int rxrpc_process_soft_ACKs(struct rxrpc_call *call,
 317                                    struct rxrpc_ackpacket *ack,
 318                                    struct sk_buff *skb)
 319 {
 320         struct rxrpc_skb_priv *sp;
 321         struct sk_buff *txb;
 322         unsigned long *p_txb, resend_at;
 323         int loop;
 324         u8 sacks[RXRPC_MAXACKS], resend;
 325
 326         _enter("{%d,%d},{%d},",
 327                call->acks_hard,
 328                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz),
 329                ack->nAcks);
 330
 331         if (skb_copy_bits(skb, 0, sacks, ack->nAcks) < 0)
 332                 goto protocol_error;
 333
 334         resend = 0;
 335         resend_at = 0;
 336         for (loop = 0; loop < ack->nAcks; loop++) {
 337                 p_txb = call->acks_window;
 338                 p_txb += (call->acks_tail + loop) & (call->acks_winsz - 1);
 339                 smp_read_barrier_depends();
 340                 txb = (struct sk_buff *) (*p_txb & ~1);
 341                 sp = rxrpc_skb(txb);
 342
 343                 switch (sacks[loop]) {
 344                 case RXRPC_ACK_TYPE_ACK:
 345                         sp->need_resend = false;
 346                         *p_txb |= 1;
 347                         break;
 348                 case RXRPC_ACK_TYPE_NACK:
 349                         sp->need_resend = true;
 350                         *p_txb &= ~1;
 351                         resend = 1;
 352                         break;
 353                 default:
 354                         _debug("Unsupported ACK type %d", sacks[loop]);
 355                         goto protocol_error;
 356                 }
 357         }
 358
 359         smp_mb();
 360         call->acks_unacked = (call->acks_tail + loop) & (call->acks_winsz - 1);
 361
 362         /* anything not explicitly ACK'd is implicitly NACK'd, but may just not
 363          * have been received or processed yet by the far end */
 364         for (loop = call->acks_unacked;
 365              loop != call->acks_head;
 366              loop = (loop + 1) &  (call->acks_winsz - 1)
 367              ) {
 368                 p_txb = call->acks_window + loop;
 369                 smp_read_barrier_depends();
 370                 txb = (struct sk_buff *) (*p_txb & ~1);
 371                 sp = rxrpc_skb(txb);
 372
 373                 if (*p_txb & 1) {
 374                         /* packet must have been discarded */
 375                         sp->need_resend = true;
 376                         *p_txb &= ~1;
 377                         resend |= 1;
 378                 } else if (sp->need_resend) {
 379                         ;
 380                 } else if (time_after_eq(jiffies + 1, sp->resend_at)) {
 381                         sp->need_resend = true;
 382                         resend |= 1;
 383                 } else if (resend & 2) {
 384                         if (time_before(sp->resend_at, resend_at))
 385                                 resend_at = sp->resend_at;
 386                 } else {
 387                         resend_at = sp->resend_at;
 388                         resend |= 2;
 389                 }
 390         }
 391
 392         rxrpc_set_resend(call, resend, resend_at);
 393         _leave(" = 0");
 394         return 0;
 395
 396 protocol_error:
 397         _leave(" = -EPROTO");
 398         return -EPROTO;
 399 }
 400
 401 /*
 402  * discard hard-ACK'd packets from the Tx window
 403  */
 404 static void rxrpc_rotate_tx_window(struct rxrpc_call *call, u32 hard)
 405 {
 406         unsigned long _skb;
 407         int tail = call->acks_tail, old_tail;
 408         int win = CIRC_CNT(call->acks_head, tail, call->acks_winsz);
 409
 410         _enter("{%u,%u},%u", call->acks_hard, win, hard);
 411
 412         ASSERTCMP(hard - call->acks_hard, <=, win);
 413
 414         while (call->acks_hard < hard) {
 415                 smp_read_barrier_depends();
 416                 _skb = call->acks_window[tail] & ~1;
 417                 rxrpc_free_skb((struct sk_buff *) _skb);
 418                 old_tail = tail;
 419                 tail = (tail + 1) & (call->acks_winsz - 1);
 420                 call->acks_tail = tail;
 421                 if (call->acks_unacked == old_tail)
 422                         call->acks_unacked = tail;
 423                 call->acks_hard++;
 424         }
 425
 426         wake_up(&call->tx_waitq);
 427 }
 428
 429 /*
 430  * clear the Tx window in the event of a failure
 431  */
 432 static void rxrpc_clear_tx_window(struct rxrpc_call *call)
 433 {
 434         rxrpc_rotate_tx_window(call, atomic_read(&call->sequence));
 435 }
 436
 437 /*
 438  * drain the out of sequence received packet queue into the packet Rx queue
 439  */
 440 static int rxrpc_drain_rx_oos_queue(struct rxrpc_call *call)
 441 {
 442         struct rxrpc_skb_priv *sp;
 443         struct sk_buff *skb;
 444         bool terminal;
 445         int ret;
 446
 447         _enter("{%d,%d}", call->rx_data_post, call->rx_first_oos);
 448
 449         spin_lock_bh(&call->lock);
 450
 451         ret = -ECONNRESET;
 452         if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
 453                 goto socket_unavailable;
 454
 455         skb = skb_dequeue(&call->rx_oos_queue);
 456         if (skb) {
 457                 sp = rxrpc_skb(skb);
 458
 459                 _debug("drain OOS packet %d [%d]",
 460                        ntohl(sp->hdr.seq), call->rx_first_oos);
 461
 462                 if (ntohl(sp->hdr.seq) != call->rx_first_oos) {
 463                         skb_queue_head(&call->rx_oos_queue, skb);
 464                         call->rx_first_oos = ntohl(rxrpc_skb(skb)->hdr.seq);
 465                         _debug("requeue %p {%u}", skb, call->rx_first_oos);
 466                 } else {
 467                         skb->mark = RXRPC_SKB_MARK_DATA;
 468                         terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
 469                                 !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
 470                         ret = rxrpc_queue_rcv_skb(call, skb, true, terminal);
 471                         BUG_ON(ret < 0);
 472                         _debug("drain #%u", call->rx_data_post);
 473                         call->rx_data_post++;
 474
 475                         /* find out what the next packet is */
 476                         skb = skb_peek(&call->rx_oos_queue);
 477                         if (skb)
 478                                 call->rx_first_oos =
 479                                         ntohl(rxrpc_skb(skb)->hdr.seq);
 480                         else
 481                                 call->rx_first_oos = 0;
 482                         _debug("peek %p {%u}", skb, call->rx_first_oos);
 483                 }
 484         }
 485
 486         ret = 0;
 487 socket_unavailable:
 488         spin_unlock_bh(&call->lock);
 489         _leave(" = %d", ret);
 490         return ret;
 491 }
 492
 493 /*
 494  * insert an out of sequence packet into the buffer
 495  */
 496 static void rxrpc_insert_oos_packet(struct rxrpc_call *call,
 497                                     struct sk_buff *skb)
 498 {
 499         struct rxrpc_skb_priv *sp, *psp;
 500         struct sk_buff *p;
 501         u32 seq;
 502
 503         sp = rxrpc_skb(skb);
 504         seq = ntohl(sp->hdr.seq);
 505         _enter(",,{%u}", seq);
 506
 507         skb->destructor = rxrpc_packet_destructor;
 508         ASSERTCMP(sp->call, ==, NULL);
 509         sp->call = call;
 510         rxrpc_get_call(call);
 511
 512         /* insert into the buffer in sequence order */
 513         spin_lock_bh(&call->lock);
 514
 515         skb_queue_walk(&call->rx_oos_queue, p) {
 516                 psp = rxrpc_skb(p);
 517                 if (ntohl(psp->hdr.seq) > seq) {
 518                         _debug("insert oos #%u before #%u",
 519                                seq, ntohl(psp->hdr.seq));
 520                         skb_insert(p, skb, &call->rx_oos_queue);
 521                         goto inserted;
 522                 }
 523         }
 524
 525         _debug("append oos #%u", seq);
 526         skb_queue_tail(&call->rx_oos_queue, skb);
 527 inserted:
 528
 529         /* we might now have a new front to the queue */
 530         if (call->rx_first_oos == 0 || seq < call->rx_first_oos)
 531                 call->rx_first_oos = seq;
 532
 533         read_lock(&call->state_lock);
 534         if (call->state < RXRPC_CALL_COMPLETE &&
 535             call->rx_data_post == call->rx_first_oos) {
 536                 _debug("drain rx oos now");
 537                 set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
 538         }
 539         read_unlock(&call->state_lock);
 540
 541         spin_unlock_bh(&call->lock);
 542         _leave(" [stored #%u]", call->rx_first_oos);
 543 }
 544
 545 /*
 546  * clear the Tx window on final ACK reception
 547  */
 548 static void rxrpc_zap_tx_window(struct rxrpc_call *call)
 549 {
 550         struct rxrpc_skb_priv *sp;
 551         struct sk_buff *skb;
 552         unsigned long _skb, *acks_window;
 553         u8 winsz = call->acks_winsz;
 554         int tail;
 555
 556         acks_window = call->acks_window;
 557         call->acks_window = NULL;
 558
 559         while (CIRC_CNT(call->acks_head, call->acks_tail, winsz) > 0) {
 560                 tail = call->acks_tail;
 561                 smp_read_barrier_depends();
 562                 _skb = acks_window[tail] & ~1;
 563                 smp_mb();
 564                 call->acks_tail = (call->acks_tail + 1) & (winsz - 1);
 565
 566                 skb = (struct sk_buff *) _skb;
 567                 sp = rxrpc_skb(skb);
 568                 _debug("+++ clear Tx %u", ntohl(sp->hdr.seq));
 569                 rxrpc_free_skb(skb);
 570         }
 571
 572         kfree(acks_window);
 573 }
 574
 575 /*
 576  * process the extra information that may be appended to an ACK packet
 577  */
 578 static void rxrpc_extract_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
 579                                   unsigned int latest, int nAcks)
 580 {
 581         struct rxrpc_ackinfo ackinfo;
 582         struct rxrpc_peer *peer;
 583         unsigned int mtu;
 584
 585         if (skb_copy_bits(skb, nAcks + 3, &ackinfo, sizeof(ackinfo)) < 0) {
 586                 _leave(" [no ackinfo]");
 587                 return;
 588         }
 589
 590         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
 591                latest,
 592                ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU),
 593                ntohl(ackinfo.rwind), ntohl(ackinfo.jumbo_max));
 594
 595         mtu = min(ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU));
 596
 597         peer = call->conn->trans->peer;
 598         if (mtu < peer->maxdata) {
 599                 spin_lock_bh(&peer->lock);
 600                 peer->maxdata = mtu;
 601                 peer->mtu = mtu + peer->hdrsize;
 602                 spin_unlock_bh(&peer->lock);
 603                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
 604         }
 605 }
 606
 607 /*
 608  * process packets in the reception queue
 609  */
 610 static int rxrpc_process_rx_queue(struct rxrpc_call *call,
 611                                   u32 *_abort_code)
 612 {
 613         struct rxrpc_ackpacket ack;
 614         struct rxrpc_skb_priv *sp;
 615         struct sk_buff *skb;
 616         bool post_ACK;
 617         int latest;
 618         u32 hard, tx;
 619
 620         _enter("");
 621
 622 process_further:
 623         skb = skb_dequeue(&call->rx_queue);
 624         if (!skb)
 625                 return -EAGAIN;
 626
 627         _net("deferred skb %p", skb);
 628
 629         sp = rxrpc_skb(skb);
 630
 631         _debug("process %s [st %d]", rxrpc_pkts[sp->hdr.type], call->state);
 632
 633         post_ACK = false;
 634
 635         switch (sp->hdr.type) {
 636                 /* data packets that wind up here have been received out of
 637                  * order, need security processing or are jumbo packets */
 638         case RXRPC_PACKET_TYPE_DATA:
 639                 _proto("OOSQ DATA %%%u { #%u }",
 640                        ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
 641
 642                 /* secured packets must be verified and possibly decrypted */
 643                 if (rxrpc_verify_packet(call, skb, _abort_code) < 0)
 644                         goto protocol_error;
 645
 646                 rxrpc_insert_oos_packet(call, skb);
 647                 goto process_further;
 648
 649                 /* partial ACK to process */
 650         case RXRPC_PACKET_TYPE_ACK:
 651                 if (skb_copy_bits(skb, 0, &ack, sizeof(ack)) < 0) {
 652                         _debug("extraction failure");
 653                         goto protocol_error;
 654                 }
 655                 if (!skb_pull(skb, sizeof(ack)))
 656                         BUG();
 657
 658                 latest = ntohl(sp->hdr.serial);
 659                 hard = ntohl(ack.firstPacket);
 660                 tx = atomic_read(&call->sequence);
 661
 662                 _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 663                        latest,
 664                        ntohs(ack.maxSkew),
 665                        hard,
 666                        ntohl(ack.previousPacket),
 667                        ntohl(ack.serial),
 668                        rxrpc_acks(ack.reason),
 669                        ack.nAcks);
 670
 671                 rxrpc_extract_ackinfo(call, skb, latest, ack.nAcks);
 672
 673                 if (ack.reason == RXRPC_ACK_PING) {
 674                         _proto("Rx ACK %%%u PING Request", latest);
 675                         rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 676                                           sp->hdr.serial, true);
 677                 }
 678
 679                 /* discard any out-of-order or duplicate ACKs */
 680                 if (latest - call->acks_latest <= 0) {
 681                         _debug("discard ACK %d <= %d",
 682                                latest, call->acks_latest);
 683                         goto discard;
 684                 }
 685                 call->acks_latest = latest;
 686
 687                 if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
 688                     call->state != RXRPC_CALL_CLIENT_AWAIT_REPLY &&
 689                     call->state != RXRPC_CALL_SERVER_SEND_REPLY &&
 690                     call->state != RXRPC_CALL_SERVER_AWAIT_ACK)
 691                         goto discard;
 692
 693                 _debug("Tx=%d H=%u S=%d", tx, call->acks_hard, call->state);
 694
 695                 if (hard > 0) {
 696                         if (hard - 1 > tx) {
 697                                 _debug("hard-ACK'd packet %d not transmitted"
 698                                        " (%d top)",
 699                                        hard - 1, tx);
 700                                 goto protocol_error;
 701                         }
 702
 703                         if ((call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY ||
 704                              call->state == RXRPC_CALL_SERVER_AWAIT_ACK) &&
 705                             hard > tx)
 706                                 goto all_acked;
 707
 708                         smp_rmb();
 709                         rxrpc_rotate_tx_window(call, hard - 1);
 710                 }
 711
 712                 if (ack.nAcks > 0) {
 713                         if (hard - 1 + ack.nAcks > tx) {
 714                                 _debug("soft-ACK'd packet %d+%d not"
 715                                        " transmitted (%d top)",
 716                                        hard - 1, ack.nAcks, tx);
 717                                 goto protocol_error;
 718                         }
 719
 720                         if (rxrpc_process_soft_ACKs(call, &ack, skb) < 0)
 721                                 goto protocol_error;
 722                 }
 723                 goto discard;
 724
 725                 /* complete ACK to process */
 726         case RXRPC_PACKET_TYPE_ACKALL:
 727                 goto all_acked;
 728
 729                 /* abort and busy are handled elsewhere */
 730         case RXRPC_PACKET_TYPE_BUSY:
 731         case RXRPC_PACKET_TYPE_ABORT:
 732                 BUG();
 733
 734                 /* connection level events - also handled elsewhere */
 735         case RXRPC_PACKET_TYPE_CHALLENGE:
 736         case RXRPC_PACKET_TYPE_RESPONSE:
 737         case RXRPC_PACKET_TYPE_DEBUG:
 738                 BUG();
 739         }
 740
 741         /* if we've had a hard ACK that covers all the packets we've sent, then
 742          * that ends that phase of the operation */
 743 all_acked:
 744         write_lock_bh(&call->state_lock);
 745         _debug("ack all %d", call->state);
 746
 747         switch (call->state) {
 748         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 749                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 750                 break;
 751         case RXRPC_CALL_SERVER_AWAIT_ACK:
 752                 _debug("srv complete");
 753                 call->state = RXRPC_CALL_COMPLETE;
 754                 post_ACK = true;
 755                 break;
 756         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 757         case RXRPC_CALL_SERVER_RECV_REQUEST:
 758                 goto protocol_error_unlock; /* can't occur yet */
 759         default:
 760                 write_unlock_bh(&call->state_lock);
 761                 goto discard; /* assume packet left over from earlier phase */
 762         }
 763
 764         write_unlock_bh(&call->state_lock);
 765
 766         /* if all the packets we sent are hard-ACK'd, then we can discard
 767          * whatever we've got left */
 768         _debug("clear Tx %d",
 769                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
 770
 771         del_timer_sync(&call->resend_timer);
 772         clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 773         clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 774
 775         if (call->acks_window)
 776                 rxrpc_zap_tx_window(call);
 777
 778         if (post_ACK) {
 779                 /* post the final ACK message for userspace to pick up */
 780                 _debug("post ACK");
 781                 skb->mark = RXRPC_SKB_MARK_FINAL_ACK;
 782                 sp->call = call;
 783                 rxrpc_get_call(call);
 784                 spin_lock_bh(&call->lock);
 785                 if (rxrpc_queue_rcv_skb(call, skb, true, true) < 0)
 786                         BUG();
 787                 spin_unlock_bh(&call->lock);
 788                 goto process_further;
 789         }
 790
 791 discard:
 792         rxrpc_free_skb(skb);
 793         goto process_further;
 794
 795 protocol_error_unlock:
 796         write_unlock_bh(&call->state_lock);
 797 protocol_error:
 798         rxrpc_free_skb(skb);
 799         _leave(" = -EPROTO");
 800         return -EPROTO;
 801 }
 802
 803 /*
 804  * post a message to the socket Rx queue for recvmsg() to pick up
 805  */
 806 static int rxrpc_post_message(struct rxrpc_call *call, u32 mark, u32 error,
 807                               bool fatal)
 808 {
 809         struct rxrpc_skb_priv *sp;
 810         struct sk_buff *skb;
 811         int ret;
 812
 813         _enter("{%d,%lx},%u,%u,%d",
 814                call->debug_id, call->flags, mark, error, fatal);
 815
 816         /* remove timers and things for fatal messages */
 817         if (fatal) {
 818                 del_timer_sync(&call->resend_timer);
 819                 del_timer_sync(&call->ack_timer);
 820                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 821         }
 822
 823         if (mark != RXRPC_SKB_MARK_NEW_CALL &&
 824             !test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
 825                 _leave("[no userid]");
 826                 return 0;
 827         }
 828
 829         if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
 830                 skb = alloc_skb(0, GFP_NOFS);
 831                 if (!skb)
 832                         return -ENOMEM;
 833
 834                 rxrpc_new_skb(skb);
 835
 836                 skb->mark = mark;
 837
 838                 sp = rxrpc_skb(skb);
 839                 memset(sp, 0, sizeof(*sp));
 840                 sp->error = error;
 841                 sp->call = call;
 842                 rxrpc_get_call(call);
 843
 844                 spin_lock_bh(&call->lock);
 845                 ret = rxrpc_queue_rcv_skb(call, skb, true, fatal);
 846                 spin_unlock_bh(&call->lock);
 847                 BUG_ON(ret < 0);
 848         }
 849
 850         return 0;
 851 }
 852
 853 /*
 854  * handle background processing of incoming call packets and ACK / abort
 855  * generation
 856  */
 857 void rxrpc_process_call(struct work_struct *work)
 858 {
 859         struct rxrpc_call *call =
 860                 container_of(work, struct rxrpc_call, processor);
 861         struct rxrpc_ackpacket ack;
 862         struct rxrpc_ackinfo ackinfo;
 863         struct rxrpc_header hdr;
 864         struct msghdr msg;
 865         struct kvec iov[5];
 866         unsigned long bits;
 867         __be32 data, pad;
 868         size_t len;
 869         int genbit, loop, nbit, ioc, ret, mtu;
 870         u32 abort_code = RX_PROTOCOL_ERROR;
 871         u8 *acks = NULL;
 872
 873         //printk("\n--------------------\n");
 874         _enter("{%d,%s,%lx} [%lu]",
 875                call->debug_id, rxrpc_call_states[call->state], call->events,
 876                (jiffies - call->creation_jif) / (HZ / 10));
 877
 878         if (test_and_set_bit(RXRPC_CALL_PROC_BUSY, &call->flags)) {
 879                 _debug("XXXXXXXXXXXXX RUNNING ON MULTIPLE CPUS XXXXXXXXXXXXX");
 880                 return;
 881         }
 882
 883         /* there's a good chance we're going to have to send a message, so set
 884          * one up in advance */
 885         msg.msg_name    = &call->conn->trans->peer->srx.transport.sin;
 886         msg.msg_namelen = sizeof(call->conn->trans->peer->srx.transport.sin);
 887         msg.msg_control = NULL;
 888         msg.msg_controllen = 0;
 889         msg.msg_flags   = 0;
 890
 891         hdr.epoch       = call->conn->epoch;
 892         hdr.cid         = call->cid;
 893         hdr.callNumber  = call->call_id;
 894         hdr.seq         = 0;
 895         hdr.type        = RXRPC_PACKET_TYPE_ACK;
 896         hdr.flags       = call->conn->out_clientflag;
 897         hdr.userStatus  = 0;
 898         hdr.securityIndex = call->conn->security_ix;
 899         hdr._rsvd       = 0;
 900         hdr.serviceId   = call->conn->service_id;
 901
 902         memset(iov, 0, sizeof(iov));
 903         iov[0].iov_base = &hdr;
 904         iov[0].iov_len  = sizeof(hdr);
 905
 906         /* deal with events of a final nature */
 907         if (test_bit(RXRPC_CALL_RELEASE, &call->events)) {
 908                 rxrpc_release_call(call);
 909                 clear_bit(RXRPC_CALL_RELEASE, &call->events);
 910         }
 911
 912         if (test_bit(RXRPC_CALL_RCVD_ERROR, &call->events)) {
 913                 int error;
 914
 915                 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
 916                 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
 917                 clear_bit(RXRPC_CALL_ABORT, &call->events);
 918
 919                 error = call->conn->trans->peer->net_error;
 920                 _debug("post net error %d", error);
 921
 922                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NET_ERROR,
 923                                        error, true) < 0)
 924                         goto no_mem;
 925                 clear_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
 926                 goto kill_ACKs;
 927         }
 928
 929         if (test_bit(RXRPC_CALL_CONN_ABORT, &call->events)) {
 930                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
 931
 932                 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
 933                 clear_bit(RXRPC_CALL_ABORT, &call->events);
 934
 935                 _debug("post conn abort");
 936
 937                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 938                                        call->conn->error, true) < 0)
 939                         goto no_mem;
 940                 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
 941                 goto kill_ACKs;
 942         }
 943
 944         if (test_bit(RXRPC_CALL_REJECT_BUSY, &call->events)) {
 945                 hdr.type = RXRPC_PACKET_TYPE_BUSY;
 946                 genbit = RXRPC_CALL_REJECT_BUSY;
 947                 goto send_message;
 948         }
 949
 950         if (test_bit(RXRPC_CALL_ABORT, &call->events)) {
 951                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
 952
 953                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 954                                        ECONNABORTED, true) < 0)
 955                         goto no_mem;
 956                 hdr.type = RXRPC_PACKET_TYPE_ABORT;
 957                 data = htonl(call->abort_code);
 958                 iov[1].iov_base = &data;
 959                 iov[1].iov_len = sizeof(data);
 960                 genbit = RXRPC_CALL_ABORT;
 961                 goto send_message;
 962         }
 963
 964         if (test_bit(RXRPC_CALL_ACK_FINAL, &call->events)) {
 965                 genbit = RXRPC_CALL_ACK_FINAL;
 966
 967                 ack.bufferSpace = htons(8);
 968                 ack.maxSkew     = 0;
 969                 ack.serial      = 0;
 970                 ack.reason      = RXRPC_ACK_IDLE;
 971                 ack.nAcks       = 0;
 972                 call->ackr_reason = 0;
 973
 974                 spin_lock_bh(&call->lock);
 975                 ack.serial = call->ackr_serial;
 976                 ack.previousPacket = call->ackr_prev_seq;
 977                 ack.firstPacket = htonl(call->rx_data_eaten + 1);
 978                 spin_unlock_bh(&call->lock);
 979
 980                 pad = 0;
 981
 982                 iov[1].iov_base = &ack;
 983                 iov[1].iov_len  = sizeof(ack);
 984                 iov[2].iov_base = &pad;
 985                 iov[2].iov_len  = 3;
 986                 iov[3].iov_base = &ackinfo;
 987                 iov[3].iov_len  = sizeof(ackinfo);
 988                 goto send_ACK;
 989         }
 990
 991         if (call->events & ((1 << RXRPC_CALL_RCVD_BUSY) |
 992                             (1 << RXRPC_CALL_RCVD_ABORT))
 993             ) {
 994                 u32 mark;
 995
 996                 if (test_bit(RXRPC_CALL_RCVD_ABORT, &call->events))
 997                         mark = RXRPC_SKB_MARK_REMOTE_ABORT;
 998                 else
 999                         mark = RXRPC_SKB_MARK_BUSY;
1000
1001                 _debug("post abort/busy");
1002                 rxrpc_clear_tx_window(call);
1003                 if (rxrpc_post_message(call, mark, ECONNABORTED, true) < 0)
1004                         goto no_mem;
1005
1006                 clear_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
1007                 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
1008                 goto kill_ACKs;
1009         }
1010
1011         if (test_and_clear_bit(RXRPC_CALL_RCVD_ACKALL, &call->events)) {
1012                 _debug("do implicit ackall");
1013                 rxrpc_clear_tx_window(call);
1014         }
1015
1016         if (test_bit(RXRPC_CALL_LIFE_TIMER, &call->events)) {
1017                 write_lock_bh(&call->state_lock);
1018                 if (call->state <= RXRPC_CALL_COMPLETE) {
1019                         call->state = RXRPC_CALL_LOCALLY_ABORTED;
1020                         call->abort_code = RX_CALL_TIMEOUT;
1021                         set_bit(RXRPC_CALL_ABORT, &call->events);
1022                 }
1023                 write_unlock_bh(&call->state_lock);
1024
1025                 _debug("post timeout");
1026                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
1027                                        ETIME, true) < 0)
1028                         goto no_mem;
1029
1030                 clear_bit(RXRPC_CALL_LIFE_TIMER, &call->events);
1031                 goto kill_ACKs;
1032         }
1033
1034         /* deal with assorted inbound messages */
1035         if (!skb_queue_empty(&call->rx_queue)) {
1036                 switch (rxrpc_process_rx_queue(call, &abort_code)) {
1037                 case 0:
1038                 case -EAGAIN:
1039                         break;
1040                 case -ENOMEM:
1041                         goto no_mem;
1042                 case -EKEYEXPIRED:
1043                 case -EKEYREJECTED:
1044                 case -EPROTO:
1045                         rxrpc_abort_call(call, abort_code);
1046                         goto kill_ACKs;
1047                 }
1048         }
1049
1050         /* handle resending */
1051         if (test_and_clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
1052                 rxrpc_resend_timer(call);
1053         if (test_and_clear_bit(RXRPC_CALL_RESEND, &call->events))
1054                 rxrpc_resend(call);
1055
1056         /* consider sending an ordinary ACK */
1057         if (test_bit(RXRPC_CALL_ACK, &call->events)) {
1058                 _debug("send ACK: window: %d - %d { %lx }",
1059                        call->rx_data_eaten, call->ackr_win_top,
1060                        call->ackr_window[0]);
1061
1062                 if (call->state > RXRPC_CALL_SERVER_ACK_REQUEST &&
1063                     call->ackr_reason != RXRPC_ACK_PING_RESPONSE) {
1064                         /* ACK by sending reply DATA packet in this state */
1065                         clear_bit(RXRPC_CALL_ACK, &call->events);
1066                         goto maybe_reschedule;
1067                 }
1068
1069                 genbit = RXRPC_CALL_ACK;
1070
1071                 acks = kzalloc(call->ackr_win_top - call->rx_data_eaten,
1072                                GFP_NOFS);
1073                 if (!acks)
1074                         goto no_mem;
1075
1076                 //hdr.flags     = RXRPC_SLOW_START_OK;
1077                 ack.bufferSpace = htons(8);
1078                 ack.maxSkew     = 0;
1079                 ack.serial      = 0;
1080                 ack.reason      = 0;
1081
1082                 spin_lock_bh(&call->lock);
1083                 ack.reason = call->ackr_reason;
1084                 ack.serial = call->ackr_serial;
1085                 ack.previousPacket = call->ackr_prev_seq;
1086                 ack.firstPacket = htonl(call->rx_data_eaten + 1);
1087
1088                 ack.nAcks = 0;
1089                 for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
1090                         nbit = loop * BITS_PER_LONG;
1091                         for (bits = call->ackr_window[loop]; bits; bits >>= 1
1092                              ) {
1093                                 _debug("- l=%d n=%d b=%lx", loop, nbit, bits);
1094                                 if (bits & 1) {
1095                                         acks[nbit] = RXRPC_ACK_TYPE_ACK;
1096                                         ack.nAcks = nbit + 1;
1097                                 }
1098                                 nbit++;
1099                         }
1100                 }
1101                 call->ackr_reason = 0;
1102                 spin_unlock_bh(&call->lock);
1103
1104                 pad = 0;
1105
1106                 iov[1].iov_base = &ack;
1107                 iov[1].iov_len  = sizeof(ack);
1108                 iov[2].iov_base = acks;
1109                 iov[2].iov_len  = ack.nAcks;
1110                 iov[3].iov_base = &pad;
1111                 iov[3].iov_len  = 3;
1112                 iov[4].iov_base = &ackinfo;
1113                 iov[4].iov_len  = sizeof(ackinfo);
1114
1115                 switch (ack.reason) {
1116                 case RXRPC_ACK_REQUESTED:
1117                 case RXRPC_ACK_DUPLICATE:
1118                 case RXRPC_ACK_OUT_OF_SEQUENCE:
1119                 case RXRPC_ACK_EXCEEDS_WINDOW:
1120                 case RXRPC_ACK_NOSPACE:
1121                 case RXRPC_ACK_PING:
1122                 case RXRPC_ACK_PING_RESPONSE:
1123                         goto send_ACK_with_skew;
1124                 case RXRPC_ACK_DELAY:
1125                 case RXRPC_ACK_IDLE:
1126                         goto send_ACK;
1127                 }
1128         }
1129
1130         /* handle completion of security negotiations on an incoming
1131          * connection */
1132         if (test_and_clear_bit(RXRPC_CALL_SECURED, &call->events)) {
1133                 _debug("secured");
1134                 spin_lock_bh(&call->lock);
1135
1136                 if (call->state == RXRPC_CALL_SERVER_SECURING) {
1137                         _debug("securing");
1138                         write_lock(&call->conn->lock);
1139                         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1140                             !test_bit(RXRPC_CALL_RELEASE, &call->events)) {
1141                                 _debug("not released");
1142                                 call->state = RXRPC_CALL_SERVER_ACCEPTING;
1143                                 list_move_tail(&call->accept_link,
1144                                                &call->socket->acceptq);
1145                         }
1146                         write_unlock(&call->conn->lock);
1147                         read_lock(&call->state_lock);
1148                         if (call->state < RXRPC_CALL_COMPLETE)
1149                                 set_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1150                         read_unlock(&call->state_lock);
1151                 }
1152
1153                 spin_unlock_bh(&call->lock);
1154                 if (!test_bit(RXRPC_CALL_POST_ACCEPT, &call->events))
1155                         goto maybe_reschedule;
1156         }
1157
1158         /* post a notification of an acceptable connection to the app */
1159         if (test_bit(RXRPC_CALL_POST_ACCEPT, &call->events)) {
1160                 _debug("post accept");
1161                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NEW_CALL,
1162                                        0, false) < 0)
1163                         goto no_mem;
1164                 clear_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1165                 goto maybe_reschedule;
1166         }
1167
1168         /* handle incoming call acceptance */
1169         if (test_and_clear_bit(RXRPC_CALL_ACCEPTED, &call->events)) {
1170                 _debug("accepted");
1171                 ASSERTCMP(call->rx_data_post, ==, 0);
1172                 call->rx_data_post = 1;
1173                 read_lock_bh(&call->state_lock);
1174                 if (call->state < RXRPC_CALL_COMPLETE)
1175                         set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
1176                 read_unlock_bh(&call->state_lock);
1177         }
1178
1179         /* drain the out of sequence received packet queue into the packet Rx
1180          * queue */
1181         if (test_and_clear_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events)) {
1182                 while (call->rx_data_post == call->rx_first_oos)
1183                         if (rxrpc_drain_rx_oos_queue(call) < 0)
1184                                 break;
1185                 goto maybe_reschedule;
1186         }
1187
1188         /* other events may have been raised since we started checking */
1189         goto maybe_reschedule;
1190
1191 send_ACK_with_skew:
1192         ack.maxSkew = htons(atomic_read(&call->conn->hi_serial) -
1193                             ntohl(ack.serial));
1194 send_ACK:
1195         mtu = call->conn->trans->peer->if_mtu;
1196         mtu -= call->conn->trans->peer->hdrsize;
1197         ackinfo.maxMTU  = htonl(mtu);
1198         ackinfo.rwind   = htonl(32);
1199
1200         /* permit the peer to send us jumbo packets if it wants to */
1201         ackinfo.rxMTU   = htonl(5692);
1202         ackinfo.jumbo_max = htonl(4);
1203
1204         hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1205         _proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
1206                ntohl(hdr.serial),
1207                ntohs(ack.maxSkew),
1208                ntohl(ack.firstPacket),
1209                ntohl(ack.previousPacket),
1210                ntohl(ack.serial),
1211                rxrpc_acks(ack.reason),
1212                ack.nAcks);
1213
1214         del_timer_sync(&call->ack_timer);
1215         if (ack.nAcks > 0)
1216                 set_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags);
1217         goto send_message_2;
1218
1219 send_message:
1220         _debug("send message");
1221
1222         hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1223         _proto("Tx %s %%%u", rxrpc_pkts[hdr.type], ntohl(hdr.serial));
1224 send_message_2:
1225
1226         len = iov[0].iov_len;
1227         ioc = 1;
1228         if (iov[4].iov_len) {
1229                 ioc = 5;
1230                 len += iov[4].iov_len;
1231                 len += iov[3].iov_len;
1232                 len += iov[2].iov_len;
1233                 len += iov[1].iov_len;
1234         } else if (iov[3].iov_len) {
1235                 ioc = 4;
1236                 len += iov[3].iov_len;
1237                 len += iov[2].iov_len;
1238                 len += iov[1].iov_len;
1239         } else if (iov[2].iov_len) {
1240                 ioc = 3;
1241                 len += iov[2].iov_len;
1242                 len += iov[1].iov_len;
1243         } else if (iov[1].iov_len) {
1244                 ioc = 2;
1245                 len += iov[1].iov_len;
1246         }
1247
1248         ret = kernel_sendmsg(call->conn->trans->local->socket,
1249                              &msg, iov, ioc, len);
1250         if (ret < 0) {
1251                 _debug("sendmsg failed: %d", ret);
1252                 read_lock_bh(&call->state_lock);
1253                 if (call->state < RXRPC_CALL_DEAD)
1254                         rxrpc_queue_call(call);
1255                 read_unlock_bh(&call->state_lock);
1256                 goto error;
1257         }
1258
1259         switch (genbit) {
1260         case RXRPC_CALL_ABORT:
1261                 clear_bit(genbit, &call->events);
1262                 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
1263                 goto kill_ACKs;
1264
1265         case RXRPC_CALL_ACK_FINAL:
1266                 write_lock_bh(&call->state_lock);
1267                 if (call->state == RXRPC_CALL_CLIENT_FINAL_ACK)
1268                         call->state = RXRPC_CALL_COMPLETE;
1269                 write_unlock_bh(&call->state_lock);
1270                 goto kill_ACKs;
1271
1272         default:
1273                 clear_bit(genbit, &call->events);
1274                 switch (call->state) {
1275                 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
1276                 case RXRPC_CALL_CLIENT_RECV_REPLY:
1277                 case RXRPC_CALL_SERVER_RECV_REQUEST:
1278                 case RXRPC_CALL_SERVER_ACK_REQUEST:
1279                         _debug("start ACK timer");
1280                         rxrpc_propose_ACK(call, RXRPC_ACK_DELAY,
1281                                           call->ackr_serial, false);
1282                 default:
1283                         break;
1284                 }
1285                 goto maybe_reschedule;
1286         }
1287
1288 kill_ACKs:
1289         del_timer_sync(&call->ack_timer);
1290         if (test_and_clear_bit(RXRPC_CALL_ACK_FINAL, &call->events))
1291                 rxrpc_put_call(call);
1292         clear_bit(RXRPC_CALL_ACK, &call->events);
1293
1294 maybe_reschedule:
1295         if (call->events || !skb_queue_empty(&call->rx_queue)) {
1296                 read_lock_bh(&call->state_lock);
1297                 if (call->state < RXRPC_CALL_DEAD)
1298                         rxrpc_queue_call(call);
1299                 read_unlock_bh(&call->state_lock);
1300         }
1301
1302         /* don't leave aborted connections on the accept queue */
1303         if (call->state >= RXRPC_CALL_COMPLETE &&
1304             !list_empty(&call->accept_link)) {
1305                 _debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
1306                        call, call->events, call->flags,
1307                        ntohl(call->conn->cid));
1308
1309                 read_lock_bh(&call->state_lock);
1310                 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1311                     !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
1312                         rxrpc_queue_call(call);
1313                 read_unlock_bh(&call->state_lock);
1314         }
1315
1316 error:
1317         clear_bit(RXRPC_CALL_PROC_BUSY, &call->flags);
1318         kfree(acks);
1319
1320         /* because we don't want two CPUs both processing the work item for one
1321          * call at the same time, we use a flag to note when it's busy; however
1322          * this means there's a race between clearing the flag and setting the
1323          * work pending bit and the work item being processed again */
1324         if (call->events && !work_pending(&call->processor)) {
1325                 _debug("jumpstart %x", ntohl(call->conn->cid));
1326                 rxrpc_queue_call(call);
1327         }
1328
1329         _leave("");
1330         return;
1331
1332 no_mem:
1333         _debug("out of memory");
1334         goto maybe_reschedule;
1335 }