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 ([email protected])
   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/udp.h>
  17 #include <net/sock.h>
  18 #include <net/af_rxrpc.h>
  19 #include "ar-internal.h"
  20
  21 static unsigned rxrpc_ack_defer = 1;
  22
  23 static const char *rxrpc_acks[] = {
  24         "---", "REQ", "DUP", "OOS", "WIN", "MEM", "PNG", "PNR", "DLY", "IDL",
  25         "-?-"
  26 };
  27
  28 static const s8 rxrpc_ack_priority[] = {
  29         [0]                             = 0,
  30         [RXRPC_ACK_DELAY]               = 1,
  31         [RXRPC_ACK_REQUESTED]           = 2,
  32         [RXRPC_ACK_IDLE]                = 3,
  33         [RXRPC_ACK_PING_RESPONSE]       = 4,
  34         [RXRPC_ACK_DUPLICATE]           = 5,
  35         [RXRPC_ACK_OUT_OF_SEQUENCE]     = 6,
  36         [RXRPC_ACK_EXCEEDS_WINDOW]      = 7,
  37         [RXRPC_ACK_NOSPACE]             = 8,
  38 };
  39
  40 /*
  41  * propose an ACK be sent
  42  */
  43 void __rxrpc_propose_ACK(struct rxrpc_call *call, uint8_t ack_reason,
  44                          __be32 serial, bool immediate)
  45 {
  46         unsigned long expiry;
  47         s8 prior = rxrpc_ack_priority[ack_reason];
  48
  49         ASSERTCMP(prior, >, 0);
  50
  51         _enter("{%d},%s,%%%x,%u",
  52                call->debug_id, rxrpc_acks[ack_reason], ntohl(serial),
  53                immediate);
  54
  55         if (prior < rxrpc_ack_priority[call->ackr_reason]) {
  56                 if (immediate)
  57                         goto cancel_timer;
  58                 return;
  59         }
  60
  61         /* update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
  62          * numbers */
  63         if (prior == rxrpc_ack_priority[call->ackr_reason]) {
  64                 if (prior <= 4)
  65                         call->ackr_serial = serial;
  66                 if (immediate)
  67                         goto cancel_timer;
  68                 return;
  69         }
  70
  71         call->ackr_reason = ack_reason;
  72         call->ackr_serial = serial;
  73
  74         switch (ack_reason) {
  75         case RXRPC_ACK_DELAY:
  76                 _debug("run delay timer");
  77                 call->ack_timer.expires = jiffies + rxrpc_ack_timeout * HZ;
  78                 add_timer(&call->ack_timer);
  79                 return;
  80
  81         case RXRPC_ACK_IDLE:
  82                 if (!immediate) {
  83                         _debug("run defer timer");
  84                         expiry = 1;
  85                         goto run_timer;
  86                 }
  87                 goto cancel_timer;
  88
  89         case RXRPC_ACK_REQUESTED:
  90                 if (!rxrpc_ack_defer)
  91                         goto cancel_timer;
  92                 if (!immediate || serial == cpu_to_be32(1)) {
  93                         _debug("run defer timer");
  94                         expiry = rxrpc_ack_defer;
  95                         goto run_timer;
  96                 }
  97
  98         default:
  99                 _debug("immediate ACK");
 100                 goto cancel_timer;
 101         }
 102
 103 run_timer:
 104         expiry += jiffies;
 105         if (!timer_pending(&call->ack_timer) ||
 106             time_after(call->ack_timer.expires, expiry))
 107                 mod_timer(&call->ack_timer, expiry);
 108         return;
 109
 110 cancel_timer:
 111         _debug("cancel timer %%%u", ntohl(serial));
 112         try_to_del_timer_sync(&call->ack_timer);
 113         read_lock_bh(&call->state_lock);
 114         if (call->state <= RXRPC_CALL_COMPLETE &&
 115             !test_and_set_bit(RXRPC_CALL_ACK, &call->events))
 116                 rxrpc_queue_call(call);
 117         read_unlock_bh(&call->state_lock);
 118 }
 119
 120 /*
 121  * propose an ACK be sent, locking the call structure
 122  */
 123 void rxrpc_propose_ACK(struct rxrpc_call *call, uint8_t ack_reason,
 124                        __be32 serial, bool immediate)
 125 {
 126         s8 prior = rxrpc_ack_priority[ack_reason];
 127
 128         if (prior > rxrpc_ack_priority[call->ackr_reason]) {
 129                 spin_lock_bh(&call->lock);
 130                 __rxrpc_propose_ACK(call, ack_reason, serial, immediate);
 131                 spin_unlock_bh(&call->lock);
 132         }
 133 }
 134
 135 /*
 136  * set the resend timer
 137  */
 138 static void rxrpc_set_resend(struct rxrpc_call *call, u8 resend,
 139                              unsigned long resend_at)
 140 {
 141         read_lock_bh(&call->state_lock);
 142         if (call->state >= RXRPC_CALL_COMPLETE)
 143                 resend = 0;
 144
 145         if (resend & 1) {
 146                 _debug("SET RESEND");
 147                 set_bit(RXRPC_CALL_RESEND, &call->events);
 148         }
 149
 150         if (resend & 2) {
 151                 _debug("MODIFY RESEND TIMER");
 152                 set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 153                 mod_timer(&call->resend_timer, resend_at);
 154         } else {
 155                 _debug("KILL RESEND TIMER");
 156                 del_timer_sync(&call->resend_timer);
 157                 clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 158                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 159         }
 160         read_unlock_bh(&call->state_lock);
 161 }
 162
 163 /*
 164  * resend packets
 165  */
 166 static void rxrpc_resend(struct rxrpc_call *call)
 167 {
 168         struct rxrpc_skb_priv *sp;
 169         struct rxrpc_header *hdr;
 170         struct sk_buff *txb;
 171         unsigned long *p_txb, resend_at;
 172         int loop, stop;
 173         u8 resend;
 174
 175         _enter("{%d,%d,%d,%d},",
 176                call->acks_hard, call->acks_unacked,
 177                atomic_read(&call->sequence),
 178                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
 179
 180         stop = 0;
 181         resend = 0;
 182         resend_at = 0;
 183
 184         for (loop = call->acks_tail;
 185              loop != call->acks_head || stop;
 186              loop = (loop + 1) &  (call->acks_winsz - 1)
 187              ) {
 188                 p_txb = call->acks_window + loop;
 189                 smp_read_barrier_depends();
 190                 if (*p_txb & 1)
 191                         continue;
 192
 193                 txb = (struct sk_buff *) *p_txb;
 194                 sp = rxrpc_skb(txb);
 195
 196                 if (sp->need_resend) {
 197                         sp->need_resend = 0;
 198
 199                         /* each Tx packet has a new serial number */
 200                         sp->hdr.serial =
 201                                 htonl(atomic_inc_return(&call->conn->serial));
 202
 203                         hdr = (struct rxrpc_header *) txb->head;
 204                         hdr->serial = sp->hdr.serial;
 205
 206                         _proto("Tx DATA %%%u { #%d }",
 207                                ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
 208                         if (rxrpc_send_packet(call->conn->trans, txb) < 0) {
 209                                 stop = 0;
 210                                 sp->resend_at = jiffies + 3;
 211                         } else {
 212                                 sp->resend_at =
 213                                         jiffies + rxrpc_resend_timeout * HZ;
 214                         }
 215                 }
 216
 217                 if (time_after_eq(jiffies + 1, sp->resend_at)) {
 218                         sp->need_resend = 1;
 219                         resend |= 1;
 220                 } else if (resend & 2) {
 221                         if (time_before(sp->resend_at, resend_at))
 222                                 resend_at = sp->resend_at;
 223                 } else {
 224                         resend_at = sp->resend_at;
 225                         resend |= 2;
 226                 }
 227         }
 228
 229         rxrpc_set_resend(call, resend, resend_at);
 230         _leave("");
 231 }
 232
 233 /*
 234  * handle resend timer expiry
 235  */
 236 static void rxrpc_resend_timer(struct rxrpc_call *call)
 237 {
 238         struct rxrpc_skb_priv *sp;
 239         struct sk_buff *txb;
 240         unsigned long *p_txb, resend_at;
 241         int loop;
 242         u8 resend;
 243
 244         _enter("%d,%d,%d",
 245                call->acks_tail, call->acks_unacked, call->acks_head);
 246
 247         resend = 0;
 248         resend_at = 0;
 249
 250         for (loop = call->acks_unacked;
 251              loop != call->acks_head;
 252              loop = (loop + 1) &  (call->acks_winsz - 1)
 253              ) {
 254                 p_txb = call->acks_window + loop;
 255                 smp_read_barrier_depends();
 256                 txb = (struct sk_buff *) (*p_txb & ~1);
 257                 sp = rxrpc_skb(txb);
 258
 259                 ASSERT(!(*p_txb & 1));
 260
 261                 if (sp->need_resend) {
 262                         ;
 263                 } else if (time_after_eq(jiffies + 1, sp->resend_at)) {
 264                         sp->need_resend = 1;
 265                         resend |= 1;
 266                 } else if (resend & 2) {
 267                         if (time_before(sp->resend_at, resend_at))
 268                                 resend_at = sp->resend_at;
 269                 } else {
 270                         resend_at = sp->resend_at;
 271                         resend |= 2;
 272                 }
 273         }
 274
 275         rxrpc_set_resend(call, resend, resend_at);
 276         _leave("");
 277 }
 278
 279 /*
 280  * process soft ACKs of our transmitted packets
 281  * - these indicate packets the peer has or has not received, but hasn't yet
 282  *   given to the consumer, and so can still be discarded and re-requested
 283  */
 284 static int rxrpc_process_soft_ACKs(struct rxrpc_call *call,
 285                                    struct rxrpc_ackpacket *ack,
 286                                    struct sk_buff *skb)
 287 {
 288         struct rxrpc_skb_priv *sp;
 289         struct sk_buff *txb;
 290         unsigned long *p_txb, resend_at;
 291         int loop;
 292         u8 sacks[RXRPC_MAXACKS], resend;
 293
 294         _enter("{%d,%d},{%d},",
 295                call->acks_hard,
 296                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz),
 297                ack->nAcks);
 298
 299         if (skb_copy_bits(skb, 0, sacks, ack->nAcks) < 0)
 300                 goto protocol_error;
 301
 302         resend = 0;
 303         resend_at = 0;
 304         for (loop = 0; loop < ack->nAcks; loop++) {
 305                 p_txb = call->acks_window;
 306                 p_txb += (call->acks_tail + loop) & (call->acks_winsz - 1);
 307                 smp_read_barrier_depends();
 308                 txb = (struct sk_buff *) (*p_txb & ~1);
 309                 sp = rxrpc_skb(txb);
 310
 311                 switch (sacks[loop]) {
 312                 case RXRPC_ACK_TYPE_ACK:
 313                         sp->need_resend = 0;
 314                         *p_txb |= 1;
 315                         break;
 316                 case RXRPC_ACK_TYPE_NACK:
 317                         sp->need_resend = 1;
 318                         *p_txb &= ~1;
 319                         resend = 1;
 320                         break;
 321                 default:
 322                         _debug("Unsupported ACK type %d", sacks[loop]);
 323                         goto protocol_error;
 324                 }
 325         }
 326
 327         smp_mb();
 328         call->acks_unacked = (call->acks_tail + loop) & (call->acks_winsz - 1);
 329
 330         /* anything not explicitly ACK'd is implicitly NACK'd, but may just not
 331          * have been received or processed yet by the far end */
 332         for (loop = call->acks_unacked;
 333              loop != call->acks_head;
 334              loop = (loop + 1) &  (call->acks_winsz - 1)
 335              ) {
 336                 p_txb = call->acks_window + loop;
 337                 smp_read_barrier_depends();
 338                 txb = (struct sk_buff *) (*p_txb & ~1);
 339                 sp = rxrpc_skb(txb);
 340
 341                 if (*p_txb & 1) {
 342                         /* packet must have been discarded */
 343                         sp->need_resend = 1;
 344                         *p_txb &= ~1;
 345                         resend |= 1;
 346                 } else if (sp->need_resend) {
 347                         ;
 348                 } else if (time_after_eq(jiffies + 1, sp->resend_at)) {
 349                         sp->need_resend = 1;
 350                         resend |= 1;
 351                 } else if (resend & 2) {
 352                         if (time_before(sp->resend_at, resend_at))
 353                                 resend_at = sp->resend_at;
 354                 } else {
 355                         resend_at = sp->resend_at;
 356                         resend |= 2;
 357                 }
 358         }
 359
 360         rxrpc_set_resend(call, resend, resend_at);
 361         _leave(" = 0");
 362         return 0;
 363
 364 protocol_error:
 365         _leave(" = -EPROTO");
 366         return -EPROTO;
 367 }
 368
 369 /*
 370  * discard hard-ACK'd packets from the Tx window
 371  */
 372 static void rxrpc_rotate_tx_window(struct rxrpc_call *call, u32 hard)
 373 {
 374         struct rxrpc_skb_priv *sp;
 375         unsigned long _skb;
 376         int tail = call->acks_tail, old_tail;
 377         int win = CIRC_CNT(call->acks_head, tail, call->acks_winsz);
 378
 379         _enter("{%u,%u},%u", call->acks_hard, win, hard);
 380
 381         ASSERTCMP(hard - call->acks_hard, <=, win);
 382
 383         while (call->acks_hard < hard) {
 384                 smp_read_barrier_depends();
 385                 _skb = call->acks_window[tail] & ~1;
 386                 sp = rxrpc_skb((struct sk_buff *) _skb);
 387                 rxrpc_free_skb((struct sk_buff *) _skb);
 388                 old_tail = tail;
 389                 tail = (tail + 1) & (call->acks_winsz - 1);
 390                 call->acks_tail = tail;
 391                 if (call->acks_unacked == old_tail)
 392                         call->acks_unacked = tail;
 393                 call->acks_hard++;
 394         }
 395
 396         wake_up(&call->tx_waitq);
 397 }
 398
 399 /*
 400  * clear the Tx window in the event of a failure
 401  */
 402 static void rxrpc_clear_tx_window(struct rxrpc_call *call)
 403 {
 404         rxrpc_rotate_tx_window(call, atomic_read(&call->sequence));
 405 }
 406
 407 /*
 408  * drain the out of sequence received packet queue into the packet Rx queue
 409  */
 410 static int rxrpc_drain_rx_oos_queue(struct rxrpc_call *call)
 411 {
 412         struct rxrpc_skb_priv *sp;
 413         struct sk_buff *skb;
 414         bool terminal;
 415         int ret;
 416
 417         _enter("{%d,%d}", call->rx_data_post, call->rx_first_oos);
 418
 419         spin_lock_bh(&call->lock);
 420
 421         ret = -ECONNRESET;
 422         if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
 423                 goto socket_unavailable;
 424
 425         skb = skb_dequeue(&call->rx_oos_queue);
 426         if (skb) {
 427                 sp = rxrpc_skb(skb);
 428
 429                 _debug("drain OOS packet %d [%d]",
 430                        ntohl(sp->hdr.seq), call->rx_first_oos);
 431
 432                 if (ntohl(sp->hdr.seq) != call->rx_first_oos) {
 433                         skb_queue_head(&call->rx_oos_queue, skb);
 434                         call->rx_first_oos = ntohl(rxrpc_skb(skb)->hdr.seq);
 435                         _debug("requeue %p {%u}", skb, call->rx_first_oos);
 436                 } else {
 437                         skb->mark = RXRPC_SKB_MARK_DATA;
 438                         terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
 439                                 !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
 440                         ret = rxrpc_queue_rcv_skb(call, skb, true, terminal);
 441                         BUG_ON(ret < 0);
 442                         _debug("drain #%u", call->rx_data_post);
 443                         call->rx_data_post++;
 444
 445                         /* find out what the next packet is */
 446                         skb = skb_peek(&call->rx_oos_queue);
 447                         if (skb)
 448                                 call->rx_first_oos =
 449                                         ntohl(rxrpc_skb(skb)->hdr.seq);
 450                         else
 451                                 call->rx_first_oos = 0;
 452                         _debug("peek %p {%u}", skb, call->rx_first_oos);
 453                 }
 454         }
 455
 456         ret = 0;
 457 socket_unavailable:
 458         spin_unlock_bh(&call->lock);
 459         _leave(" = %d", ret);
 460         return ret;
 461 }
 462
 463 /*
 464  * insert an out of sequence packet into the buffer
 465  */
 466 static void rxrpc_insert_oos_packet(struct rxrpc_call *call,
 467                                     struct sk_buff *skb)
 468 {
 469         struct rxrpc_skb_priv *sp, *psp;
 470         struct sk_buff *p;
 471         u32 seq;
 472
 473         sp = rxrpc_skb(skb);
 474         seq = ntohl(sp->hdr.seq);
 475         _enter(",,{%u}", seq);
 476
 477         skb->destructor = rxrpc_packet_destructor;
 478         ASSERTCMP(sp->call, ==, NULL);
 479         sp->call = call;
 480         rxrpc_get_call(call);
 481
 482         /* insert into the buffer in sequence order */
 483         spin_lock_bh(&call->lock);
 484
 485         skb_queue_walk(&call->rx_oos_queue, p) {
 486                 psp = rxrpc_skb(p);
 487                 if (ntohl(psp->hdr.seq) > seq) {
 488                         _debug("insert oos #%u before #%u",
 489                                seq, ntohl(psp->hdr.seq));
 490                         skb_insert(p, skb, &call->rx_oos_queue);
 491                         goto inserted;
 492                 }
 493         }
 494
 495         _debug("append oos #%u", seq);
 496         skb_queue_tail(&call->rx_oos_queue, skb);
 497 inserted:
 498
 499         /* we might now have a new front to the queue */
 500         if (call->rx_first_oos == 0 || seq < call->rx_first_oos)
 501                 call->rx_first_oos = seq;
 502
 503         read_lock(&call->state_lock);
 504         if (call->state < RXRPC_CALL_COMPLETE &&
 505             call->rx_data_post == call->rx_first_oos) {
 506                 _debug("drain rx oos now");
 507                 set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
 508         }
 509         read_unlock(&call->state_lock);
 510
 511         spin_unlock_bh(&call->lock);
 512         _leave(" [stored #%u]", call->rx_first_oos);
 513 }
 514
 515 /*
 516  * clear the Tx window on final ACK reception
 517  */
 518 static void rxrpc_zap_tx_window(struct rxrpc_call *call)
 519 {
 520         struct rxrpc_skb_priv *sp;
 521         struct sk_buff *skb;
 522         unsigned long _skb, *acks_window;
 523         uint8_t winsz = call->acks_winsz;
 524         int tail;
 525
 526         acks_window = call->acks_window;
 527         call->acks_window = NULL;
 528
 529         while (CIRC_CNT(call->acks_head, call->acks_tail, winsz) > 0) {
 530                 tail = call->acks_tail;
 531                 smp_read_barrier_depends();
 532                 _skb = acks_window[tail] & ~1;
 533                 smp_mb();
 534                 call->acks_tail = (call->acks_tail + 1) & (winsz - 1);
 535
 536                 skb = (struct sk_buff *) _skb;
 537                 sp = rxrpc_skb(skb);
 538                 _debug("+++ clear Tx %u", ntohl(sp->hdr.seq));
 539                 rxrpc_free_skb(skb);
 540         }
 541
 542         kfree(acks_window);
 543 }
 544
 545 /*
 546  * process packets in the reception queue
 547  */
 548 static int rxrpc_process_rx_queue(struct rxrpc_call *call,
 549                                   u32 *_abort_code)
 550 {
 551         struct rxrpc_ackpacket ack;
 552         struct rxrpc_skb_priv *sp;
 553         struct sk_buff *skb;
 554         bool post_ACK;
 555         int latest;
 556         u32 hard, tx;
 557
 558         _enter("");
 559
 560 process_further:
 561         skb = skb_dequeue(&call->rx_queue);
 562         if (!skb)
 563                 return -EAGAIN;
 564
 565         _net("deferred skb %p", skb);
 566
 567         sp = rxrpc_skb(skb);
 568
 569         _debug("process %s [st %d]", rxrpc_pkts[sp->hdr.type], call->state);
 570
 571         post_ACK = false;
 572
 573         switch (sp->hdr.type) {
 574                 /* data packets that wind up here have been received out of
 575                  * order, need security processing or are jumbo packets */
 576         case RXRPC_PACKET_TYPE_DATA:
 577                 _proto("OOSQ DATA %%%u { #%u }",
 578                        ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
 579
 580                 /* secured packets must be verified and possibly decrypted */
 581                 if (rxrpc_verify_packet(call, skb, _abort_code) < 0)
 582                         goto protocol_error;
 583
 584                 rxrpc_insert_oos_packet(call, skb);
 585                 goto process_further;
 586
 587                 /* partial ACK to process */
 588         case RXRPC_PACKET_TYPE_ACK:
 589                 if (skb_copy_bits(skb, 0, &ack, sizeof(ack)) < 0) {
 590                         _debug("extraction failure");
 591                         goto protocol_error;
 592                 }
 593                 if (!skb_pull(skb, sizeof(ack)))
 594                         BUG();
 595
 596                 latest = ntohl(sp->hdr.serial);
 597                 hard = ntohl(ack.firstPacket);
 598                 tx = atomic_read(&call->sequence);
 599
 600                 _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
 601                        latest,
 602                        ntohs(ack.maxSkew),
 603                        hard,
 604                        ntohl(ack.previousPacket),
 605                        ntohl(ack.serial),
 606                        rxrpc_acks[ack.reason],
 607                        ack.nAcks);
 608
 609                 if (ack.reason == RXRPC_ACK_PING) {
 610                         _proto("Rx ACK %%%u PING Request", latest);
 611                         rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
 612                                           sp->hdr.serial, true);
 613                 }
 614
 615                 /* discard any out-of-order or duplicate ACKs */
 616                 if (latest - call->acks_latest <= 0) {
 617                         _debug("discard ACK %d <= %d",
 618                                latest, call->acks_latest);
 619                         goto discard;
 620                 }
 621                 call->acks_latest = latest;
 622
 623                 if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
 624                     call->state != RXRPC_CALL_CLIENT_AWAIT_REPLY &&
 625                     call->state != RXRPC_CALL_SERVER_SEND_REPLY &&
 626                     call->state != RXRPC_CALL_SERVER_AWAIT_ACK)
 627                         goto discard;
 628
 629                 _debug("Tx=%d H=%u S=%d", tx, call->acks_hard, call->state);
 630
 631                 if (hard > 0) {
 632                         if (hard - 1 > tx) {
 633                                 _debug("hard-ACK'd packet %d not transmitted"
 634                                        " (%d top)",
 635                                        hard - 1, tx);
 636                                 goto protocol_error;
 637                         }
 638
 639                         if ((call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY ||
 640                              call->state == RXRPC_CALL_SERVER_AWAIT_ACK) &&
 641                             hard > tx)
 642                                 goto all_acked;
 643
 644                         smp_rmb();
 645                         rxrpc_rotate_tx_window(call, hard - 1);
 646                 }
 647
 648                 if (ack.nAcks > 0) {
 649                         if (hard - 1 + ack.nAcks > tx) {
 650                                 _debug("soft-ACK'd packet %d+%d not"
 651                                        " transmitted (%d top)",
 652                                        hard - 1, ack.nAcks, tx);
 653                                 goto protocol_error;
 654                         }
 655
 656                         if (rxrpc_process_soft_ACKs(call, &ack, skb) < 0)
 657                                 goto protocol_error;
 658                 }
 659                 goto discard;
 660
 661                 /* complete ACK to process */
 662         case RXRPC_PACKET_TYPE_ACKALL:
 663                 goto all_acked;
 664
 665                 /* abort and busy are handled elsewhere */
 666         case RXRPC_PACKET_TYPE_BUSY:
 667         case RXRPC_PACKET_TYPE_ABORT:
 668                 BUG();
 669
 670                 /* connection level events - also handled elsewhere */
 671         case RXRPC_PACKET_TYPE_CHALLENGE:
 672         case RXRPC_PACKET_TYPE_RESPONSE:
 673         case RXRPC_PACKET_TYPE_DEBUG:
 674                 BUG();
 675         }
 676
 677         /* if we've had a hard ACK that covers all the packets we've sent, then
 678          * that ends that phase of the operation */
 679 all_acked:
 680         write_lock_bh(&call->state_lock);
 681         _debug("ack all %d", call->state);
 682
 683         switch (call->state) {
 684         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
 685                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
 686                 break;
 687         case RXRPC_CALL_SERVER_AWAIT_ACK:
 688                 _debug("srv complete");
 689                 call->state = RXRPC_CALL_COMPLETE;
 690                 post_ACK = true;
 691                 break;
 692         case RXRPC_CALL_CLIENT_SEND_REQUEST:
 693         case RXRPC_CALL_SERVER_RECV_REQUEST:
 694                 goto protocol_error_unlock; /* can't occur yet */
 695         default:
 696                 write_unlock_bh(&call->state_lock);
 697                 goto discard; /* assume packet left over from earlier phase */
 698         }
 699
 700         write_unlock_bh(&call->state_lock);
 701
 702         /* if all the packets we sent are hard-ACK'd, then we can discard
 703          * whatever we've got left */
 704         _debug("clear Tx %d",
 705                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
 706
 707         del_timer_sync(&call->resend_timer);
 708         clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 709         clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 710
 711         if (call->acks_window)
 712                 rxrpc_zap_tx_window(call);
 713
 714         if (post_ACK) {
 715                 /* post the final ACK message for userspace to pick up */
 716                 _debug("post ACK");
 717                 skb->mark = RXRPC_SKB_MARK_FINAL_ACK;
 718                 sp->call = call;
 719                 rxrpc_get_call(call);
 720                 spin_lock_bh(&call->lock);
 721                 if (rxrpc_queue_rcv_skb(call, skb, true, true) < 0)
 722                         BUG();
 723                 spin_unlock_bh(&call->lock);
 724                 goto process_further;
 725         }
 726
 727 discard:
 728         rxrpc_free_skb(skb);
 729         goto process_further;
 730
 731 protocol_error_unlock:
 732         write_unlock_bh(&call->state_lock);
 733 protocol_error:
 734         rxrpc_free_skb(skb);
 735         _leave(" = -EPROTO");
 736         return -EPROTO;
 737 }
 738
 739 /*
 740  * post a message to the socket Rx queue for recvmsg() to pick up
 741  */
 742 static int rxrpc_post_message(struct rxrpc_call *call, u32 mark, u32 error,
 743                               bool fatal)
 744 {
 745         struct rxrpc_skb_priv *sp;
 746         struct sk_buff *skb;
 747         int ret;
 748
 749         _enter("{%d,%lx},%u,%u,%d",
 750                call->debug_id, call->flags, mark, error, fatal);
 751
 752         /* remove timers and things for fatal messages */
 753         if (fatal) {
 754                 del_timer_sync(&call->resend_timer);
 755                 del_timer_sync(&call->ack_timer);
 756                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 757         }
 758
 759         if (mark != RXRPC_SKB_MARK_NEW_CALL &&
 760             !test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
 761                 _leave("[no userid]");
 762                 return 0;
 763         }
 764
 765         if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
 766                 skb = alloc_skb(0, GFP_NOFS);
 767                 if (!skb)
 768                         return -ENOMEM;
 769
 770                 rxrpc_new_skb(skb);
 771
 772                 skb->mark = mark;
 773
 774                 sp = rxrpc_skb(skb);
 775                 memset(sp, 0, sizeof(*sp));
 776                 sp->error = error;
 777                 sp->call = call;
 778                 rxrpc_get_call(call);
 779
 780                 spin_lock_bh(&call->lock);
 781                 ret = rxrpc_queue_rcv_skb(call, skb, true, fatal);
 782                 spin_unlock_bh(&call->lock);
 783                 if (ret < 0)
 784                         BUG();
 785         }
 786
 787         return 0;
 788 }
 789
 790 /*
 791  * handle background processing of incoming call packets and ACK / abort
 792  * generation
 793  */
 794 void rxrpc_process_call(struct work_struct *work)
 795 {
 796         struct rxrpc_call *call =
 797                 container_of(work, struct rxrpc_call, processor);
 798         struct rxrpc_ackpacket ack;
 799         struct rxrpc_ackinfo ackinfo;
 800         struct rxrpc_header hdr;
 801         struct msghdr msg;
 802         struct kvec iov[5];
 803         unsigned long bits;
 804         __be32 data;
 805         size_t len;
 806         int genbit, loop, nbit, ioc, ret;
 807         u32 abort_code = RX_PROTOCOL_ERROR;
 808         u8 *acks = NULL;
 809
 810         //printk("\n--------------------\n");
 811         _enter("{%d,%s,%lx} [%lu]",
 812                call->debug_id, rxrpc_call_states[call->state], call->events,
 813                (jiffies - call->creation_jif) / (HZ / 10));
 814
 815         if (test_and_set_bit(RXRPC_CALL_PROC_BUSY, &call->flags)) {
 816                 _debug("XXXXXXXXXXXXX RUNNING ON MULTIPLE CPUS XXXXXXXXXXXXX");
 817                 return;
 818         }
 819
 820         /* there's a good chance we're going to have to send a message, so set
 821          * one up in advance */
 822         msg.msg_name    = &call->conn->trans->peer->srx.transport.sin;
 823         msg.msg_namelen = sizeof(call->conn->trans->peer->srx.transport.sin);
 824         msg.msg_control = NULL;
 825         msg.msg_controllen = 0;
 826         msg.msg_flags   = 0;
 827
 828         hdr.epoch       = call->conn->epoch;
 829         hdr.cid         = call->cid;
 830         hdr.callNumber  = call->call_id;
 831         hdr.seq         = 0;
 832         hdr.type        = RXRPC_PACKET_TYPE_ACK;
 833         hdr.flags       = call->conn->out_clientflag;
 834         hdr.userStatus  = 0;
 835         hdr.securityIndex = call->conn->security_ix;
 836         hdr._rsvd       = 0;
 837         hdr.serviceId   = call->conn->service_id;
 838
 839         memset(iov, 0, sizeof(iov));
 840         iov[0].iov_base = &hdr;
 841         iov[0].iov_len  = sizeof(hdr);
 842
 843         /* deal with events of a final nature */
 844         if (test_bit(RXRPC_CALL_RELEASE, &call->events)) {
 845                 rxrpc_release_call(call);
 846                 clear_bit(RXRPC_CALL_RELEASE, &call->events);
 847         }
 848
 849         if (test_bit(RXRPC_CALL_RCVD_ERROR, &call->events)) {
 850                 int error;
 851
 852                 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
 853                 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
 854                 clear_bit(RXRPC_CALL_ABORT, &call->events);
 855
 856                 error = call->conn->trans->peer->net_error;
 857                 _debug("post net error %d", error);
 858
 859                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NET_ERROR,
 860                                        error, true) < 0)
 861                         goto no_mem;
 862                 clear_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
 863                 goto kill_ACKs;
 864         }
 865
 866         if (test_bit(RXRPC_CALL_CONN_ABORT, &call->events)) {
 867                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
 868
 869                 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
 870                 clear_bit(RXRPC_CALL_ABORT, &call->events);
 871
 872                 _debug("post conn abort");
 873
 874                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 875                                        call->conn->error, true) < 0)
 876                         goto no_mem;
 877                 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
 878                 goto kill_ACKs;
 879         }
 880
 881         if (test_bit(RXRPC_CALL_REJECT_BUSY, &call->events)) {
 882                 hdr.type = RXRPC_PACKET_TYPE_BUSY;
 883                 genbit = RXRPC_CALL_REJECT_BUSY;
 884                 goto send_message;
 885         }
 886
 887         if (test_bit(RXRPC_CALL_ABORT, &call->events)) {
 888                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
 889
 890                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 891                                        ECONNABORTED, true) < 0)
 892                         goto no_mem;
 893                 hdr.type = RXRPC_PACKET_TYPE_ABORT;
 894                 data = htonl(call->abort_code);
 895                 iov[1].iov_base = &data;
 896                 iov[1].iov_len = sizeof(data);
 897                 genbit = RXRPC_CALL_ABORT;
 898                 goto send_message;
 899         }
 900
 901         if (test_bit(RXRPC_CALL_ACK_FINAL, &call->events)) {
 902                 hdr.type = RXRPC_PACKET_TYPE_ACKALL;
 903                 genbit = RXRPC_CALL_ACK_FINAL;
 904                 goto send_message;
 905         }
 906
 907         if (call->events & ((1 << RXRPC_CALL_RCVD_BUSY) |
 908                             (1 << RXRPC_CALL_RCVD_ABORT))
 909             ) {
 910                 u32 mark;
 911
 912                 if (test_bit(RXRPC_CALL_RCVD_ABORT, &call->events))
 913                         mark = RXRPC_SKB_MARK_REMOTE_ABORT;
 914                 else
 915                         mark = RXRPC_SKB_MARK_BUSY;
 916
 917                 _debug("post abort/busy");
 918                 rxrpc_clear_tx_window(call);
 919                 if (rxrpc_post_message(call, mark, ECONNABORTED, true) < 0)
 920                         goto no_mem;
 921
 922                 clear_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
 923                 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
 924                 goto kill_ACKs;
 925         }
 926
 927         if (test_and_clear_bit(RXRPC_CALL_RCVD_ACKALL, &call->events)) {
 928                 _debug("do implicit ackall");
 929                 rxrpc_clear_tx_window(call);
 930         }
 931
 932         if (test_bit(RXRPC_CALL_LIFE_TIMER, &call->events)) {
 933                 write_lock_bh(&call->state_lock);
 934                 if (call->state <= RXRPC_CALL_COMPLETE) {
 935                         call->state = RXRPC_CALL_LOCALLY_ABORTED;
 936                         call->abort_code = RX_CALL_TIMEOUT;
 937                         set_bit(RXRPC_CALL_ABORT, &call->events);
 938                 }
 939                 write_unlock_bh(&call->state_lock);
 940
 941                 _debug("post timeout");
 942                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
 943                                        ETIME, true) < 0)
 944                         goto no_mem;
 945
 946                 clear_bit(RXRPC_CALL_LIFE_TIMER, &call->events);
 947                 goto kill_ACKs;
 948         }
 949
 950         /* deal with assorted inbound messages */
 951         if (!skb_queue_empty(&call->rx_queue)) {
 952                 switch (rxrpc_process_rx_queue(call, &abort_code)) {
 953                 case 0:
 954                 case -EAGAIN:
 955                         break;
 956                 case -ENOMEM:
 957                         goto no_mem;
 958                 case -EKEYEXPIRED:
 959                 case -EKEYREJECTED:
 960                 case -EPROTO:
 961                         rxrpc_abort_call(call, abort_code);
 962                         goto kill_ACKs;
 963                 }
 964         }
 965
 966         /* handle resending */
 967         if (test_and_clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
 968                 rxrpc_resend_timer(call);
 969         if (test_and_clear_bit(RXRPC_CALL_RESEND, &call->events))
 970                 rxrpc_resend(call);
 971
 972         /* consider sending an ordinary ACK */
 973         if (test_bit(RXRPC_CALL_ACK, &call->events)) {
 974                 __be32 pad;
 975
 976                 _debug("send ACK: window: %d - %d { %lx }",
 977                        call->rx_data_eaten, call->ackr_win_top,
 978                        call->ackr_window[0]);
 979
 980                 if (call->state > RXRPC_CALL_SERVER_ACK_REQUEST &&
 981                     call->ackr_reason != RXRPC_ACK_PING_RESPONSE) {
 982                         /* ACK by sending reply DATA packet in this state */
 983                         clear_bit(RXRPC_CALL_ACK, &call->events);
 984                         goto maybe_reschedule;
 985                 }
 986
 987                 genbit = RXRPC_CALL_ACK;
 988
 989                 acks = kzalloc(call->ackr_win_top - call->rx_data_eaten,
 990                                GFP_NOFS);
 991                 if (!acks)
 992                         goto no_mem;
 993
 994                 //hdr.flags     = RXRPC_SLOW_START_OK;
 995                 ack.bufferSpace = htons(8);
 996                 ack.maxSkew     = 0;
 997                 ack.serial      = 0;
 998                 ack.reason      = 0;
 999
1000                 ackinfo.rxMTU   = htonl(5692);
1001 //              ackinfo.rxMTU   = htonl(call->conn->trans->peer->maxdata);
1002                 ackinfo.maxMTU  = htonl(call->conn->trans->peer->maxdata);
1003                 ackinfo.rwind   = htonl(32);
1004                 ackinfo.jumbo_max = htonl(4);
1005
1006                 spin_lock_bh(&call->lock);
1007                 ack.reason = call->ackr_reason;
1008                 ack.serial = call->ackr_serial;
1009                 ack.previousPacket = call->ackr_prev_seq;
1010                 ack.firstPacket = htonl(call->rx_data_eaten + 1);
1011
1012                 ack.nAcks = 0;
1013                 for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
1014                         nbit = loop * BITS_PER_LONG;
1015                         for (bits = call->ackr_window[loop]; bits; bits >>= 1
1016                              ) {
1017                                 _debug("- l=%d n=%d b=%lx", loop, nbit, bits);
1018                                 if (bits & 1) {
1019                                         acks[nbit] = RXRPC_ACK_TYPE_ACK;
1020                                         ack.nAcks = nbit + 1;
1021                                 }
1022                                 nbit++;
1023                         }
1024                 }
1025                 call->ackr_reason = 0;
1026                 spin_unlock_bh(&call->lock);
1027
1028                 pad = 0;
1029
1030                 iov[1].iov_base = &ack;
1031                 iov[1].iov_len  = sizeof(ack);
1032                 iov[2].iov_base = acks;
1033                 iov[2].iov_len  = ack.nAcks;
1034                 iov[3].iov_base = &pad;
1035                 iov[3].iov_len  = 3;
1036                 iov[4].iov_base = &ackinfo;
1037                 iov[4].iov_len  = sizeof(ackinfo);
1038
1039                 switch (ack.reason) {
1040                 case RXRPC_ACK_REQUESTED:
1041                 case RXRPC_ACK_DUPLICATE:
1042                 case RXRPC_ACK_OUT_OF_SEQUENCE:
1043                 case RXRPC_ACK_EXCEEDS_WINDOW:
1044                 case RXRPC_ACK_NOSPACE:
1045                 case RXRPC_ACK_PING:
1046                 case RXRPC_ACK_PING_RESPONSE:
1047                         goto send_ACK_with_skew;
1048                 case RXRPC_ACK_DELAY:
1049                 case RXRPC_ACK_IDLE:
1050                         goto send_ACK;
1051                 }
1052         }
1053
1054         /* handle completion of security negotiations on an incoming
1055          * connection */
1056         if (test_and_clear_bit(RXRPC_CALL_SECURED, &call->events)) {
1057                 _debug("secured");
1058                 spin_lock_bh(&call->lock);
1059
1060                 if (call->state == RXRPC_CALL_SERVER_SECURING) {
1061                         _debug("securing");
1062                         write_lock(&call->conn->lock);
1063                         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1064                             !test_bit(RXRPC_CALL_RELEASE, &call->events)) {
1065                                 _debug("not released");
1066                                 call->state = RXRPC_CALL_SERVER_ACCEPTING;
1067                                 list_move_tail(&call->accept_link,
1068                                                &call->socket->acceptq);
1069                         }
1070                         write_unlock(&call->conn->lock);
1071                         read_lock(&call->state_lock);
1072                         if (call->state < RXRPC_CALL_COMPLETE)
1073                                 set_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1074                         read_unlock(&call->state_lock);
1075                 }
1076
1077                 spin_unlock_bh(&call->lock);
1078                 if (!test_bit(RXRPC_CALL_POST_ACCEPT, &call->events))
1079                         goto maybe_reschedule;
1080         }
1081
1082         /* post a notification of an acceptable connection to the app */
1083         if (test_bit(RXRPC_CALL_POST_ACCEPT, &call->events)) {
1084                 _debug("post accept");
1085                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NEW_CALL,
1086                                        0, false) < 0)
1087                         goto no_mem;
1088                 clear_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1089                 goto maybe_reschedule;
1090         }
1091
1092         /* handle incoming call acceptance */
1093         if (test_and_clear_bit(RXRPC_CALL_ACCEPTED, &call->events)) {
1094                 _debug("accepted");
1095                 ASSERTCMP(call->rx_data_post, ==, 0);
1096                 call->rx_data_post = 1;
1097                 read_lock_bh(&call->state_lock);
1098                 if (call->state < RXRPC_CALL_COMPLETE)
1099                         set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
1100                 read_unlock_bh(&call->state_lock);
1101         }
1102
1103         /* drain the out of sequence received packet queue into the packet Rx
1104          * queue */
1105         if (test_and_clear_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events)) {
1106                 while (call->rx_data_post == call->rx_first_oos)
1107                         if (rxrpc_drain_rx_oos_queue(call) < 0)
1108                                 break;
1109                 goto maybe_reschedule;
1110         }
1111
1112         /* other events may have been raised since we started checking */
1113         goto maybe_reschedule;
1114
1115 send_ACK_with_skew:
1116         ack.maxSkew = htons(atomic_read(&call->conn->hi_serial) -
1117                             ntohl(ack.serial));
1118 send_ACK:
1119         hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1120         _proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
1121                ntohl(hdr.serial),
1122                ntohs(ack.maxSkew),
1123                ntohl(ack.firstPacket),
1124                ntohl(ack.previousPacket),
1125                ntohl(ack.serial),
1126                rxrpc_acks[ack.reason],
1127                ack.nAcks);
1128
1129         del_timer_sync(&call->ack_timer);
1130         if (ack.nAcks > 0)
1131                 set_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags);
1132         goto send_message_2;
1133
1134 send_message:
1135         _debug("send message");
1136
1137         hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1138         _proto("Tx %s %%%u", rxrpc_pkts[hdr.type], ntohl(hdr.serial));
1139 send_message_2:
1140
1141         len = iov[0].iov_len;
1142         ioc = 1;
1143         if (iov[4].iov_len) {
1144                 ioc = 5;
1145                 len += iov[4].iov_len;
1146                 len += iov[3].iov_len;
1147                 len += iov[2].iov_len;
1148                 len += iov[1].iov_len;
1149         } else if (iov[3].iov_len) {
1150                 ioc = 4;
1151                 len += iov[3].iov_len;
1152                 len += iov[2].iov_len;
1153                 len += iov[1].iov_len;
1154         } else if (iov[2].iov_len) {
1155                 ioc = 3;
1156                 len += iov[2].iov_len;
1157                 len += iov[1].iov_len;
1158         } else if (iov[1].iov_len) {
1159                 ioc = 2;
1160                 len += iov[1].iov_len;
1161         }
1162
1163         ret = kernel_sendmsg(call->conn->trans->local->socket,
1164                              &msg, iov, ioc, len);
1165         if (ret < 0) {
1166                 _debug("sendmsg failed: %d", ret);
1167                 read_lock_bh(&call->state_lock);
1168                 if (call->state < RXRPC_CALL_DEAD)
1169                         rxrpc_queue_call(call);
1170                 read_unlock_bh(&call->state_lock);
1171                 goto error;
1172         }
1173
1174         switch (genbit) {
1175         case RXRPC_CALL_ABORT:
1176                 clear_bit(genbit, &call->events);
1177                 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
1178                 goto kill_ACKs;
1179
1180         case RXRPC_CALL_ACK_FINAL:
1181                 write_lock_bh(&call->state_lock);
1182                 if (call->state == RXRPC_CALL_CLIENT_FINAL_ACK)
1183                         call->state = RXRPC_CALL_COMPLETE;
1184                 write_unlock_bh(&call->state_lock);
1185                 goto kill_ACKs;
1186
1187         default:
1188                 clear_bit(genbit, &call->events);
1189                 switch (call->state) {
1190                 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
1191                 case RXRPC_CALL_CLIENT_RECV_REPLY:
1192                 case RXRPC_CALL_SERVER_RECV_REQUEST:
1193                 case RXRPC_CALL_SERVER_ACK_REQUEST:
1194                         _debug("start ACK timer");
1195                         rxrpc_propose_ACK(call, RXRPC_ACK_DELAY,
1196                                           call->ackr_serial, false);
1197                 default:
1198                         break;
1199                 }
1200                 goto maybe_reschedule;
1201         }
1202
1203 kill_ACKs:
1204         del_timer_sync(&call->ack_timer);
1205         if (test_and_clear_bit(RXRPC_CALL_ACK_FINAL, &call->events))
1206                 rxrpc_put_call(call);
1207         clear_bit(RXRPC_CALL_ACK, &call->events);
1208
1209 maybe_reschedule:
1210         if (call->events || !skb_queue_empty(&call->rx_queue)) {
1211                 read_lock_bh(&call->state_lock);
1212                 if (call->state < RXRPC_CALL_DEAD)
1213                         rxrpc_queue_call(call);
1214                 read_unlock_bh(&call->state_lock);
1215         }
1216
1217         /* don't leave aborted connections on the accept queue */
1218         if (call->state >= RXRPC_CALL_COMPLETE &&
1219             !list_empty(&call->accept_link)) {
1220                 _debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
1221                        call, call->events, call->flags,
1222                        ntohl(call->conn->cid));
1223
1224                 read_lock_bh(&call->state_lock);
1225                 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1226                     !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
1227                         rxrpc_queue_call(call);
1228                 read_unlock_bh(&call->state_lock);
1229         }
1230
1231 error:
1232         clear_bit(RXRPC_CALL_PROC_BUSY, &call->flags);
1233         kfree(acks);
1234
1235         /* because we don't want two CPUs both processing the work item for one
1236          * call at the same time, we use a flag to note when it's busy; however
1237          * this means there's a race between clearing the flag and setting the
1238          * work pending bit and the work item being processed again */
1239         if (call->events && !work_pending(&call->processor)) {
1240                 _debug("jumpstart %x", ntohl(call->conn->cid));
1241                 rxrpc_queue_call(call);
1242         }
1243
1244         _leave("");
1245         return;
1246
1247 no_mem:
1248         _debug("out of memory");
1249         goto maybe_reschedule;
1250 }