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TOMOYO Linux Cross Reference
Linux/net/rxrpc/ar-ack.c

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  1 /* Management of Tx window, Tx resend, ACKs and out-of-sequence reception
  2  *
  3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
  4  * Written by David Howells (dhowells@redhat.com)
  5  *
  6  * This program is free software; you can redistribute it and/or
  7  * modify it under the terms of the GNU General Public License
  8  * as published by the Free Software Foundation; either version
  9  * 2 of the License, or (at your option) any later version.
 10  */
 11 
 12 #include <linux/module.h>
 13 #include <linux/circ_buf.h>
 14 #include <linux/net.h>
 15 #include <linux/skbuff.h>
 16 #include <linux/slab.h>
 17 #include <linux/udp.h>
 18 #include <net/sock.h>
 19 #include <net/af_rxrpc.h>
 20 #include "ar-internal.h"
 21 
 22 static unsigned int rxrpc_ack_defer = 1;
 23 
 24 static const char *const rxrpc_acks[] = {
 25         "---", "REQ", "DUP", "OOS", "WIN", "MEM", "PNG", "PNR", "DLY", "IDL",
 26         "-?-"
 27 };
 28 
 29 static const s8 rxrpc_ack_priority[] = {
 30         [0]                             = 0,
 31         [RXRPC_ACK_DELAY]               = 1,
 32         [RXRPC_ACK_REQUESTED]           = 2,
 33         [RXRPC_ACK_IDLE]                = 3,
 34         [RXRPC_ACK_PING_RESPONSE]       = 4,
 35         [RXRPC_ACK_DUPLICATE]           = 5,
 36         [RXRPC_ACK_OUT_OF_SEQUENCE]     = 6,
 37         [RXRPC_ACK_EXCEEDS_WINDOW]      = 7,
 38         [RXRPC_ACK_NOSPACE]             = 8,
 39 };
 40 
 41 /*
 42  * propose an ACK be sent
 43  */
 44 void __rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
 45                          __be32 serial, bool immediate)
 46 {
 47         unsigned long expiry;
 48         s8 prior = rxrpc_ack_priority[ack_reason];
 49 
 50         ASSERTCMP(prior, >, 0);
 51 
 52         _enter("{%d},%s,%%%x,%u",
 53                call->debug_id, rxrpc_acks[ack_reason], ntohl(serial),
 54                immediate);
 55 
 56         if (prior < rxrpc_ack_priority[call->ackr_reason]) {
 57                 if (immediate)
 58                         goto cancel_timer;
 59                 return;
 60         }
 61 
 62         /* update DELAY, IDLE, REQUESTED and PING_RESPONSE ACK serial
 63          * numbers */
 64         if (prior == rxrpc_ack_priority[call->ackr_reason]) {
 65                 if (prior <= 4)
 66                         call->ackr_serial = serial;
 67                 if (immediate)
 68                         goto cancel_timer;
 69                 return;
 70         }
 71 
 72         call->ackr_reason = ack_reason;
 73         call->ackr_serial = serial;
 74 
 75         switch (ack_reason) {
 76         case RXRPC_ACK_DELAY:
 77                 _debug("run delay timer");
 78                 call->ack_timer.expires = jiffies + rxrpc_ack_timeout * HZ;
 79                 add_timer(&call->ack_timer);
 80                 return;
 81 
 82         case RXRPC_ACK_IDLE:
 83                 if (!immediate) {
 84                         _debug("run defer timer");
 85                         expiry = 1;
 86                         goto run_timer;
 87                 }
 88                 goto cancel_timer;
 89 
 90         case RXRPC_ACK_REQUESTED:
 91                 if (!rxrpc_ack_defer)
 92                         goto cancel_timer;
 93                 if (!immediate || serial == cpu_to_be32(1)) {
 94                         _debug("run defer timer");
 95                         expiry = rxrpc_ack_defer;
 96                         goto run_timer;
 97                 }
 98 
 99         default:
100                 _debug("immediate ACK");
101                 goto cancel_timer;
102         }
103 
104 run_timer:
105         expiry += jiffies;
106         if (!timer_pending(&call->ack_timer) ||
107             time_after(call->ack_timer.expires, expiry))
108                 mod_timer(&call->ack_timer, expiry);
109         return;
110 
111 cancel_timer:
112         _debug("cancel timer %%%u", ntohl(serial));
113         try_to_del_timer_sync(&call->ack_timer);
114         read_lock_bh(&call->state_lock);
115         if (call->state <= RXRPC_CALL_COMPLETE &&
116             !test_and_set_bit(RXRPC_CALL_ACK, &call->events))
117                 rxrpc_queue_call(call);
118         read_unlock_bh(&call->state_lock);
119 }
120 
121 /*
122  * propose an ACK be sent, locking the call structure
123  */
124 void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
125                        __be32 serial, bool immediate)
126 {
127         s8 prior = rxrpc_ack_priority[ack_reason];
128 
129         if (prior > rxrpc_ack_priority[call->ackr_reason]) {
130                 spin_lock_bh(&call->lock);
131                 __rxrpc_propose_ACK(call, ack_reason, serial, immediate);
132                 spin_unlock_bh(&call->lock);
133         }
134 }
135 
136 /*
137  * set the resend timer
138  */
139 static void rxrpc_set_resend(struct rxrpc_call *call, u8 resend,
140                              unsigned long resend_at)
141 {
142         read_lock_bh(&call->state_lock);
143         if (call->state >= RXRPC_CALL_COMPLETE)
144                 resend = 0;
145 
146         if (resend & 1) {
147                 _debug("SET RESEND");
148                 set_bit(RXRPC_CALL_RESEND, &call->events);
149         }
150 
151         if (resend & 2) {
152                 _debug("MODIFY RESEND TIMER");
153                 set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
154                 mod_timer(&call->resend_timer, resend_at);
155         } else {
156                 _debug("KILL RESEND TIMER");
157                 del_timer_sync(&call->resend_timer);
158                 clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
159                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
160         }
161         read_unlock_bh(&call->state_lock);
162 }
163 
164 /*
165  * resend packets
166  */
167 static void rxrpc_resend(struct rxrpc_call *call)
168 {
169         struct rxrpc_skb_priv *sp;
170         struct rxrpc_header *hdr;
171         struct sk_buff *txb;
172         unsigned long *p_txb, resend_at;
173         int loop, stop;
174         u8 resend;
175 
176         _enter("{%d,%d,%d,%d},",
177                call->acks_hard, call->acks_unacked,
178                atomic_read(&call->sequence),
179                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
180 
181         stop = 0;
182         resend = 0;
183         resend_at = 0;
184 
185         for (loop = call->acks_tail;
186              loop != call->acks_head || stop;
187              loop = (loop + 1) &  (call->acks_winsz - 1)
188              ) {
189                 p_txb = call->acks_window + loop;
190                 smp_read_barrier_depends();
191                 if (*p_txb & 1)
192                         continue;
193 
194                 txb = (struct sk_buff *) *p_txb;
195                 sp = rxrpc_skb(txb);
196 
197                 if (sp->need_resend) {
198                         sp->need_resend = false;
199 
200                         /* each Tx packet has a new serial number */
201                         sp->hdr.serial =
202                                 htonl(atomic_inc_return(&call->conn->serial));
203 
204                         hdr = (struct rxrpc_header *) txb->head;
205                         hdr->serial = sp->hdr.serial;
206 
207                         _proto("Tx DATA %%%u { #%d }",
208                                ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
209                         if (rxrpc_send_packet(call->conn->trans, txb) < 0) {
210                                 stop = 0;
211                                 sp->resend_at = jiffies + 3;
212                         } else {
213                                 sp->resend_at =
214                                         jiffies + rxrpc_resend_timeout * HZ;
215                         }
216                 }
217 
218                 if (time_after_eq(jiffies + 1, sp->resend_at)) {
219                         sp->need_resend = true;
220                         resend |= 1;
221                 } else if (resend & 2) {
222                         if (time_before(sp->resend_at, resend_at))
223                                 resend_at = sp->resend_at;
224                 } else {
225                         resend_at = sp->resend_at;
226                         resend |= 2;
227                 }
228         }
229 
230         rxrpc_set_resend(call, resend, resend_at);
231         _leave("");
232 }
233 
234 /*
235  * handle resend timer expiry
236  */
237 static void rxrpc_resend_timer(struct rxrpc_call *call)
238 {
239         struct rxrpc_skb_priv *sp;
240         struct sk_buff *txb;
241         unsigned long *p_txb, resend_at;
242         int loop;
243         u8 resend;
244 
245         _enter("%d,%d,%d",
246                call->acks_tail, call->acks_unacked, call->acks_head);
247 
248         if (call->state >= RXRPC_CALL_COMPLETE)
249                 return;
250 
251         resend = 0;
252         resend_at = 0;
253 
254         for (loop = call->acks_unacked;
255              loop != call->acks_head;
256              loop = (loop + 1) &  (call->acks_winsz - 1)
257              ) {
258                 p_txb = call->acks_window + loop;
259                 smp_read_barrier_depends();
260                 txb = (struct sk_buff *) (*p_txb & ~1);
261                 sp = rxrpc_skb(txb);
262 
263                 ASSERT(!(*p_txb & 1));
264 
265                 if (sp->need_resend) {
266                         ;
267                 } else if (time_after_eq(jiffies + 1, sp->resend_at)) {
268                         sp->need_resend = true;
269                         resend |= 1;
270                 } else if (resend & 2) {
271                         if (time_before(sp->resend_at, resend_at))
272                                 resend_at = sp->resend_at;
273                 } else {
274                         resend_at = sp->resend_at;
275                         resend |= 2;
276                 }
277         }
278 
279         rxrpc_set_resend(call, resend, resend_at);
280         _leave("");
281 }
282 
283 /*
284  * process soft ACKs of our transmitted packets
285  * - these indicate packets the peer has or has not received, but hasn't yet
286  *   given to the consumer, and so can still be discarded and re-requested
287  */
288 static int rxrpc_process_soft_ACKs(struct rxrpc_call *call,
289                                    struct rxrpc_ackpacket *ack,
290                                    struct sk_buff *skb)
291 {
292         struct rxrpc_skb_priv *sp;
293         struct sk_buff *txb;
294         unsigned long *p_txb, resend_at;
295         int loop;
296         u8 sacks[RXRPC_MAXACKS], resend;
297 
298         _enter("{%d,%d},{%d},",
299                call->acks_hard,
300                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz),
301                ack->nAcks);
302 
303         if (skb_copy_bits(skb, 0, sacks, ack->nAcks) < 0)
304                 goto protocol_error;
305 
306         resend = 0;
307         resend_at = 0;
308         for (loop = 0; loop < ack->nAcks; loop++) {
309                 p_txb = call->acks_window;
310                 p_txb += (call->acks_tail + loop) & (call->acks_winsz - 1);
311                 smp_read_barrier_depends();
312                 txb = (struct sk_buff *) (*p_txb & ~1);
313                 sp = rxrpc_skb(txb);
314 
315                 switch (sacks[loop]) {
316                 case RXRPC_ACK_TYPE_ACK:
317                         sp->need_resend = false;
318                         *p_txb |= 1;
319                         break;
320                 case RXRPC_ACK_TYPE_NACK:
321                         sp->need_resend = true;
322                         *p_txb &= ~1;
323                         resend = 1;
324                         break;
325                 default:
326                         _debug("Unsupported ACK type %d", sacks[loop]);
327                         goto protocol_error;
328                 }
329         }
330 
331         smp_mb();
332         call->acks_unacked = (call->acks_tail + loop) & (call->acks_winsz - 1);
333 
334         /* anything not explicitly ACK'd is implicitly NACK'd, but may just not
335          * have been received or processed yet by the far end */
336         for (loop = call->acks_unacked;
337              loop != call->acks_head;
338              loop = (loop + 1) &  (call->acks_winsz - 1)
339              ) {
340                 p_txb = call->acks_window + loop;
341                 smp_read_barrier_depends();
342                 txb = (struct sk_buff *) (*p_txb & ~1);
343                 sp = rxrpc_skb(txb);
344 
345                 if (*p_txb & 1) {
346                         /* packet must have been discarded */
347                         sp->need_resend = true;
348                         *p_txb &= ~1;
349                         resend |= 1;
350                 } else if (sp->need_resend) {
351                         ;
352                 } else if (time_after_eq(jiffies + 1, sp->resend_at)) {
353                         sp->need_resend = true;
354                         resend |= 1;
355                 } else if (resend & 2) {
356                         if (time_before(sp->resend_at, resend_at))
357                                 resend_at = sp->resend_at;
358                 } else {
359                         resend_at = sp->resend_at;
360                         resend |= 2;
361                 }
362         }
363 
364         rxrpc_set_resend(call, resend, resend_at);
365         _leave(" = 0");
366         return 0;
367 
368 protocol_error:
369         _leave(" = -EPROTO");
370         return -EPROTO;
371 }
372 
373 /*
374  * discard hard-ACK'd packets from the Tx window
375  */
376 static void rxrpc_rotate_tx_window(struct rxrpc_call *call, u32 hard)
377 {
378         unsigned long _skb;
379         int tail = call->acks_tail, old_tail;
380         int win = CIRC_CNT(call->acks_head, tail, call->acks_winsz);
381 
382         _enter("{%u,%u},%u", call->acks_hard, win, hard);
383 
384         ASSERTCMP(hard - call->acks_hard, <=, win);
385 
386         while (call->acks_hard < hard) {
387                 smp_read_barrier_depends();
388                 _skb = call->acks_window[tail] & ~1;
389                 rxrpc_free_skb((struct sk_buff *) _skb);
390                 old_tail = tail;
391                 tail = (tail + 1) & (call->acks_winsz - 1);
392                 call->acks_tail = tail;
393                 if (call->acks_unacked == old_tail)
394                         call->acks_unacked = tail;
395                 call->acks_hard++;
396         }
397 
398         wake_up(&call->tx_waitq);
399 }
400 
401 /*
402  * clear the Tx window in the event of a failure
403  */
404 static void rxrpc_clear_tx_window(struct rxrpc_call *call)
405 {
406         rxrpc_rotate_tx_window(call, atomic_read(&call->sequence));
407 }
408 
409 /*
410  * drain the out of sequence received packet queue into the packet Rx queue
411  */
412 static int rxrpc_drain_rx_oos_queue(struct rxrpc_call *call)
413 {
414         struct rxrpc_skb_priv *sp;
415         struct sk_buff *skb;
416         bool terminal;
417         int ret;
418 
419         _enter("{%d,%d}", call->rx_data_post, call->rx_first_oos);
420 
421         spin_lock_bh(&call->lock);
422 
423         ret = -ECONNRESET;
424         if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
425                 goto socket_unavailable;
426 
427         skb = skb_dequeue(&call->rx_oos_queue);
428         if (skb) {
429                 sp = rxrpc_skb(skb);
430 
431                 _debug("drain OOS packet %d [%d]",
432                        ntohl(sp->hdr.seq), call->rx_first_oos);
433 
434                 if (ntohl(sp->hdr.seq) != call->rx_first_oos) {
435                         skb_queue_head(&call->rx_oos_queue, skb);
436                         call->rx_first_oos = ntohl(rxrpc_skb(skb)->hdr.seq);
437                         _debug("requeue %p {%u}", skb, call->rx_first_oos);
438                 } else {
439                         skb->mark = RXRPC_SKB_MARK_DATA;
440                         terminal = ((sp->hdr.flags & RXRPC_LAST_PACKET) &&
441                                 !(sp->hdr.flags & RXRPC_CLIENT_INITIATED));
442                         ret = rxrpc_queue_rcv_skb(call, skb, true, terminal);
443                         BUG_ON(ret < 0);
444                         _debug("drain #%u", call->rx_data_post);
445                         call->rx_data_post++;
446 
447                         /* find out what the next packet is */
448                         skb = skb_peek(&call->rx_oos_queue);
449                         if (skb)
450                                 call->rx_first_oos =
451                                         ntohl(rxrpc_skb(skb)->hdr.seq);
452                         else
453                                 call->rx_first_oos = 0;
454                         _debug("peek %p {%u}", skb, call->rx_first_oos);
455                 }
456         }
457 
458         ret = 0;
459 socket_unavailable:
460         spin_unlock_bh(&call->lock);
461         _leave(" = %d", ret);
462         return ret;
463 }
464 
465 /*
466  * insert an out of sequence packet into the buffer
467  */
468 static void rxrpc_insert_oos_packet(struct rxrpc_call *call,
469                                     struct sk_buff *skb)
470 {
471         struct rxrpc_skb_priv *sp, *psp;
472         struct sk_buff *p;
473         u32 seq;
474 
475         sp = rxrpc_skb(skb);
476         seq = ntohl(sp->hdr.seq);
477         _enter(",,{%u}", seq);
478 
479         skb->destructor = rxrpc_packet_destructor;
480         ASSERTCMP(sp->call, ==, NULL);
481         sp->call = call;
482         rxrpc_get_call(call);
483 
484         /* insert into the buffer in sequence order */
485         spin_lock_bh(&call->lock);
486 
487         skb_queue_walk(&call->rx_oos_queue, p) {
488                 psp = rxrpc_skb(p);
489                 if (ntohl(psp->hdr.seq) > seq) {
490                         _debug("insert oos #%u before #%u",
491                                seq, ntohl(psp->hdr.seq));
492                         skb_insert(p, skb, &call->rx_oos_queue);
493                         goto inserted;
494                 }
495         }
496 
497         _debug("append oos #%u", seq);
498         skb_queue_tail(&call->rx_oos_queue, skb);
499 inserted:
500 
501         /* we might now have a new front to the queue */
502         if (call->rx_first_oos == 0 || seq < call->rx_first_oos)
503                 call->rx_first_oos = seq;
504 
505         read_lock(&call->state_lock);
506         if (call->state < RXRPC_CALL_COMPLETE &&
507             call->rx_data_post == call->rx_first_oos) {
508                 _debug("drain rx oos now");
509                 set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
510         }
511         read_unlock(&call->state_lock);
512 
513         spin_unlock_bh(&call->lock);
514         _leave(" [stored #%u]", call->rx_first_oos);
515 }
516 
517 /*
518  * clear the Tx window on final ACK reception
519  */
520 static void rxrpc_zap_tx_window(struct rxrpc_call *call)
521 {
522         struct rxrpc_skb_priv *sp;
523         struct sk_buff *skb;
524         unsigned long _skb, *acks_window;
525         u8 winsz = call->acks_winsz;
526         int tail;
527 
528         acks_window = call->acks_window;
529         call->acks_window = NULL;
530 
531         while (CIRC_CNT(call->acks_head, call->acks_tail, winsz) > 0) {
532                 tail = call->acks_tail;
533                 smp_read_barrier_depends();
534                 _skb = acks_window[tail] & ~1;
535                 smp_mb();
536                 call->acks_tail = (call->acks_tail + 1) & (winsz - 1);
537 
538                 skb = (struct sk_buff *) _skb;
539                 sp = rxrpc_skb(skb);
540                 _debug("+++ clear Tx %u", ntohl(sp->hdr.seq));
541                 rxrpc_free_skb(skb);
542         }
543 
544         kfree(acks_window);
545 }
546 
547 /*
548  * process the extra information that may be appended to an ACK packet
549  */
550 static void rxrpc_extract_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
551                                   unsigned int latest, int nAcks)
552 {
553         struct rxrpc_ackinfo ackinfo;
554         struct rxrpc_peer *peer;
555         unsigned int mtu;
556 
557         if (skb_copy_bits(skb, nAcks + 3, &ackinfo, sizeof(ackinfo)) < 0) {
558                 _leave(" [no ackinfo]");
559                 return;
560         }
561 
562         _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
563                latest,
564                ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU),
565                ntohl(ackinfo.rwind), ntohl(ackinfo.jumbo_max));
566 
567         mtu = min(ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU));
568 
569         peer = call->conn->trans->peer;
570         if (mtu < peer->maxdata) {
571                 spin_lock_bh(&peer->lock);
572                 peer->maxdata = mtu;
573                 peer->mtu = mtu + peer->hdrsize;
574                 spin_unlock_bh(&peer->lock);
575                 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
576         }
577 }
578 
579 /*
580  * process packets in the reception queue
581  */
582 static int rxrpc_process_rx_queue(struct rxrpc_call *call,
583                                   u32 *_abort_code)
584 {
585         struct rxrpc_ackpacket ack;
586         struct rxrpc_skb_priv *sp;
587         struct sk_buff *skb;
588         bool post_ACK;
589         int latest;
590         u32 hard, tx;
591 
592         _enter("");
593 
594 process_further:
595         skb = skb_dequeue(&call->rx_queue);
596         if (!skb)
597                 return -EAGAIN;
598 
599         _net("deferred skb %p", skb);
600 
601         sp = rxrpc_skb(skb);
602 
603         _debug("process %s [st %d]", rxrpc_pkts[sp->hdr.type], call->state);
604 
605         post_ACK = false;
606 
607         switch (sp->hdr.type) {
608                 /* data packets that wind up here have been received out of
609                  * order, need security processing or are jumbo packets */
610         case RXRPC_PACKET_TYPE_DATA:
611                 _proto("OOSQ DATA %%%u { #%u }",
612                        ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
613 
614                 /* secured packets must be verified and possibly decrypted */
615                 if (rxrpc_verify_packet(call, skb, _abort_code) < 0)
616                         goto protocol_error;
617 
618                 rxrpc_insert_oos_packet(call, skb);
619                 goto process_further;
620 
621                 /* partial ACK to process */
622         case RXRPC_PACKET_TYPE_ACK:
623                 if (skb_copy_bits(skb, 0, &ack, sizeof(ack)) < 0) {
624                         _debug("extraction failure");
625                         goto protocol_error;
626                 }
627                 if (!skb_pull(skb, sizeof(ack)))
628                         BUG();
629 
630                 latest = ntohl(sp->hdr.serial);
631                 hard = ntohl(ack.firstPacket);
632                 tx = atomic_read(&call->sequence);
633 
634                 _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
635                        latest,
636                        ntohs(ack.maxSkew),
637                        hard,
638                        ntohl(ack.previousPacket),
639                        ntohl(ack.serial),
640                        rxrpc_acks[ack.reason],
641                        ack.nAcks);
642 
643                 rxrpc_extract_ackinfo(call, skb, latest, ack.nAcks);
644 
645                 if (ack.reason == RXRPC_ACK_PING) {
646                         _proto("Rx ACK %%%u PING Request", latest);
647                         rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
648                                           sp->hdr.serial, true);
649                 }
650 
651                 /* discard any out-of-order or duplicate ACKs */
652                 if (latest - call->acks_latest <= 0) {
653                         _debug("discard ACK %d <= %d",
654                                latest, call->acks_latest);
655                         goto discard;
656                 }
657                 call->acks_latest = latest;
658 
659                 if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
660                     call->state != RXRPC_CALL_CLIENT_AWAIT_REPLY &&
661                     call->state != RXRPC_CALL_SERVER_SEND_REPLY &&
662                     call->state != RXRPC_CALL_SERVER_AWAIT_ACK)
663                         goto discard;
664 
665                 _debug("Tx=%d H=%u S=%d", tx, call->acks_hard, call->state);
666 
667                 if (hard > 0) {
668                         if (hard - 1 > tx) {
669                                 _debug("hard-ACK'd packet %d not transmitted"
670                                        " (%d top)",
671                                        hard - 1, tx);
672                                 goto protocol_error;
673                         }
674 
675                         if ((call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY ||
676                              call->state == RXRPC_CALL_SERVER_AWAIT_ACK) &&
677                             hard > tx)
678                                 goto all_acked;
679 
680                         smp_rmb();
681                         rxrpc_rotate_tx_window(call, hard - 1);
682                 }
683 
684                 if (ack.nAcks > 0) {
685                         if (hard - 1 + ack.nAcks > tx) {
686                                 _debug("soft-ACK'd packet %d+%d not"
687                                        " transmitted (%d top)",
688                                        hard - 1, ack.nAcks, tx);
689                                 goto protocol_error;
690                         }
691 
692                         if (rxrpc_process_soft_ACKs(call, &ack, skb) < 0)
693                                 goto protocol_error;
694                 }
695                 goto discard;
696 
697                 /* complete ACK to process */
698         case RXRPC_PACKET_TYPE_ACKALL:
699                 goto all_acked;
700 
701                 /* abort and busy are handled elsewhere */
702         case RXRPC_PACKET_TYPE_BUSY:
703         case RXRPC_PACKET_TYPE_ABORT:
704                 BUG();
705 
706                 /* connection level events - also handled elsewhere */
707         case RXRPC_PACKET_TYPE_CHALLENGE:
708         case RXRPC_PACKET_TYPE_RESPONSE:
709         case RXRPC_PACKET_TYPE_DEBUG:
710                 BUG();
711         }
712 
713         /* if we've had a hard ACK that covers all the packets we've sent, then
714          * that ends that phase of the operation */
715 all_acked:
716         write_lock_bh(&call->state_lock);
717         _debug("ack all %d", call->state);
718 
719         switch (call->state) {
720         case RXRPC_CALL_CLIENT_AWAIT_REPLY:
721                 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
722                 break;
723         case RXRPC_CALL_SERVER_AWAIT_ACK:
724                 _debug("srv complete");
725                 call->state = RXRPC_CALL_COMPLETE;
726                 post_ACK = true;
727                 break;
728         case RXRPC_CALL_CLIENT_SEND_REQUEST:
729         case RXRPC_CALL_SERVER_RECV_REQUEST:
730                 goto protocol_error_unlock; /* can't occur yet */
731         default:
732                 write_unlock_bh(&call->state_lock);
733                 goto discard; /* assume packet left over from earlier phase */
734         }
735 
736         write_unlock_bh(&call->state_lock);
737 
738         /* if all the packets we sent are hard-ACK'd, then we can discard
739          * whatever we've got left */
740         _debug("clear Tx %d",
741                CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
742 
743         del_timer_sync(&call->resend_timer);
744         clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
745         clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
746 
747         if (call->acks_window)
748                 rxrpc_zap_tx_window(call);
749 
750         if (post_ACK) {
751                 /* post the final ACK message for userspace to pick up */
752                 _debug("post ACK");
753                 skb->mark = RXRPC_SKB_MARK_FINAL_ACK;
754                 sp->call = call;
755                 rxrpc_get_call(call);
756                 spin_lock_bh(&call->lock);
757                 if (rxrpc_queue_rcv_skb(call, skb, true, true) < 0)
758                         BUG();
759                 spin_unlock_bh(&call->lock);
760                 goto process_further;
761         }
762 
763 discard:
764         rxrpc_free_skb(skb);
765         goto process_further;
766 
767 protocol_error_unlock:
768         write_unlock_bh(&call->state_lock);
769 protocol_error:
770         rxrpc_free_skb(skb);
771         _leave(" = -EPROTO");
772         return -EPROTO;
773 }
774 
775 /*
776  * post a message to the socket Rx queue for recvmsg() to pick up
777  */
778 static int rxrpc_post_message(struct rxrpc_call *call, u32 mark, u32 error,
779                               bool fatal)
780 {
781         struct rxrpc_skb_priv *sp;
782         struct sk_buff *skb;
783         int ret;
784 
785         _enter("{%d,%lx},%u,%u,%d",
786                call->debug_id, call->flags, mark, error, fatal);
787 
788         /* remove timers and things for fatal messages */
789         if (fatal) {
790                 del_timer_sync(&call->resend_timer);
791                 del_timer_sync(&call->ack_timer);
792                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
793         }
794 
795         if (mark != RXRPC_SKB_MARK_NEW_CALL &&
796             !test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
797                 _leave("[no userid]");
798                 return 0;
799         }
800 
801         if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
802                 skb = alloc_skb(0, GFP_NOFS);
803                 if (!skb)
804                         return -ENOMEM;
805 
806                 rxrpc_new_skb(skb);
807 
808                 skb->mark = mark;
809 
810                 sp = rxrpc_skb(skb);
811                 memset(sp, 0, sizeof(*sp));
812                 sp->error = error;
813                 sp->call = call;
814                 rxrpc_get_call(call);
815 
816                 spin_lock_bh(&call->lock);
817                 ret = rxrpc_queue_rcv_skb(call, skb, true, fatal);
818                 spin_unlock_bh(&call->lock);
819                 BUG_ON(ret < 0);
820         }
821 
822         return 0;
823 }
824 
825 /*
826  * handle background processing of incoming call packets and ACK / abort
827  * generation
828  */
829 void rxrpc_process_call(struct work_struct *work)
830 {
831         struct rxrpc_call *call =
832                 container_of(work, struct rxrpc_call, processor);
833         struct rxrpc_ackpacket ack;
834         struct rxrpc_ackinfo ackinfo;
835         struct rxrpc_header hdr;
836         struct msghdr msg;
837         struct kvec iov[5];
838         unsigned long bits;
839         __be32 data, pad;
840         size_t len;
841         int genbit, loop, nbit, ioc, ret, mtu;
842         u32 abort_code = RX_PROTOCOL_ERROR;
843         u8 *acks = NULL;
844 
845         //printk("\n--------------------\n");
846         _enter("{%d,%s,%lx} [%lu]",
847                call->debug_id, rxrpc_call_states[call->state], call->events,
848                (jiffies - call->creation_jif) / (HZ / 10));
849 
850         if (test_and_set_bit(RXRPC_CALL_PROC_BUSY, &call->flags)) {
851                 _debug("XXXXXXXXXXXXX RUNNING ON MULTIPLE CPUS XXXXXXXXXXXXX");
852                 return;
853         }
854 
855         /* there's a good chance we're going to have to send a message, so set
856          * one up in advance */
857         msg.msg_name    = &call->conn->trans->peer->srx.transport.sin;
858         msg.msg_namelen = sizeof(call->conn->trans->peer->srx.transport.sin);
859         msg.msg_control = NULL;
860         msg.msg_controllen = 0;
861         msg.msg_flags   = 0;
862 
863         hdr.epoch       = call->conn->epoch;
864         hdr.cid         = call->cid;
865         hdr.callNumber  = call->call_id;
866         hdr.seq         = 0;
867         hdr.type        = RXRPC_PACKET_TYPE_ACK;
868         hdr.flags       = call->conn->out_clientflag;
869         hdr.userStatus  = 0;
870         hdr.securityIndex = call->conn->security_ix;
871         hdr._rsvd       = 0;
872         hdr.serviceId   = call->conn->service_id;
873 
874         memset(iov, 0, sizeof(iov));
875         iov[0].iov_base = &hdr;
876         iov[0].iov_len  = sizeof(hdr);
877 
878         /* deal with events of a final nature */
879         if (test_bit(RXRPC_CALL_RELEASE, &call->events)) {
880                 rxrpc_release_call(call);
881                 clear_bit(RXRPC_CALL_RELEASE, &call->events);
882         }
883 
884         if (test_bit(RXRPC_CALL_RCVD_ERROR, &call->events)) {
885                 int error;
886 
887                 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
888                 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
889                 clear_bit(RXRPC_CALL_ABORT, &call->events);
890 
891                 error = call->conn->trans->peer->net_error;
892                 _debug("post net error %d", error);
893 
894                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NET_ERROR,
895                                        error, true) < 0)
896                         goto no_mem;
897                 clear_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
898                 goto kill_ACKs;
899         }
900 
901         if (test_bit(RXRPC_CALL_CONN_ABORT, &call->events)) {
902                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
903 
904                 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
905                 clear_bit(RXRPC_CALL_ABORT, &call->events);
906 
907                 _debug("post conn abort");
908 
909                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
910                                        call->conn->error, true) < 0)
911                         goto no_mem;
912                 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
913                 goto kill_ACKs;
914         }
915 
916         if (test_bit(RXRPC_CALL_REJECT_BUSY, &call->events)) {
917                 hdr.type = RXRPC_PACKET_TYPE_BUSY;
918                 genbit = RXRPC_CALL_REJECT_BUSY;
919                 goto send_message;
920         }
921 
922         if (test_bit(RXRPC_CALL_ABORT, &call->events)) {
923                 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
924 
925                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
926                                        ECONNABORTED, true) < 0)
927                         goto no_mem;
928                 hdr.type = RXRPC_PACKET_TYPE_ABORT;
929                 data = htonl(call->abort_code);
930                 iov[1].iov_base = &data;
931                 iov[1].iov_len = sizeof(data);
932                 genbit = RXRPC_CALL_ABORT;
933                 goto send_message;
934         }
935 
936         if (test_bit(RXRPC_CALL_ACK_FINAL, &call->events)) {
937                 genbit = RXRPC_CALL_ACK_FINAL;
938 
939                 ack.bufferSpace = htons(8);
940                 ack.maxSkew     = 0;
941                 ack.serial      = 0;
942                 ack.reason      = RXRPC_ACK_IDLE;
943                 ack.nAcks       = 0;
944                 call->ackr_reason = 0;
945 
946                 spin_lock_bh(&call->lock);
947                 ack.serial = call->ackr_serial;
948                 ack.previousPacket = call->ackr_prev_seq;
949                 ack.firstPacket = htonl(call->rx_data_eaten + 1);
950                 spin_unlock_bh(&call->lock);
951 
952                 pad = 0;
953 
954                 iov[1].iov_base = &ack;
955                 iov[1].iov_len  = sizeof(ack);
956                 iov[2].iov_base = &pad;
957                 iov[2].iov_len  = 3;
958                 iov[3].iov_base = &ackinfo;
959                 iov[3].iov_len  = sizeof(ackinfo);
960                 goto send_ACK;
961         }
962 
963         if (call->events & ((1 << RXRPC_CALL_RCVD_BUSY) |
964                             (1 << RXRPC_CALL_RCVD_ABORT))
965             ) {
966                 u32 mark;
967 
968                 if (test_bit(RXRPC_CALL_RCVD_ABORT, &call->events))
969                         mark = RXRPC_SKB_MARK_REMOTE_ABORT;
970                 else
971                         mark = RXRPC_SKB_MARK_BUSY;
972 
973                 _debug("post abort/busy");
974                 rxrpc_clear_tx_window(call);
975                 if (rxrpc_post_message(call, mark, ECONNABORTED, true) < 0)
976                         goto no_mem;
977 
978                 clear_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
979                 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
980                 goto kill_ACKs;
981         }
982 
983         if (test_and_clear_bit(RXRPC_CALL_RCVD_ACKALL, &call->events)) {
984                 _debug("do implicit ackall");
985                 rxrpc_clear_tx_window(call);
986         }
987 
988         if (test_bit(RXRPC_CALL_LIFE_TIMER, &call->events)) {
989                 write_lock_bh(&call->state_lock);
990                 if (call->state <= RXRPC_CALL_COMPLETE) {
991                         call->state = RXRPC_CALL_LOCALLY_ABORTED;
992                         call->abort_code = RX_CALL_TIMEOUT;
993                         set_bit(RXRPC_CALL_ABORT, &call->events);
994                 }
995                 write_unlock_bh(&call->state_lock);
996 
997                 _debug("post timeout");
998                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
999                                        ETIME, true) < 0)
1000                         goto no_mem;
1001 
1002                 clear_bit(RXRPC_CALL_LIFE_TIMER, &call->events);
1003                 goto kill_ACKs;
1004         }
1005 
1006         /* deal with assorted inbound messages */
1007         if (!skb_queue_empty(&call->rx_queue)) {
1008                 switch (rxrpc_process_rx_queue(call, &abort_code)) {
1009                 case 0:
1010                 case -EAGAIN:
1011                         break;
1012                 case -ENOMEM:
1013                         goto no_mem;
1014                 case -EKEYEXPIRED:
1015                 case -EKEYREJECTED:
1016                 case -EPROTO:
1017                         rxrpc_abort_call(call, abort_code);
1018                         goto kill_ACKs;
1019                 }
1020         }
1021 
1022         /* handle resending */
1023         if (test_and_clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
1024                 rxrpc_resend_timer(call);
1025         if (test_and_clear_bit(RXRPC_CALL_RESEND, &call->events))
1026                 rxrpc_resend(call);
1027 
1028         /* consider sending an ordinary ACK */
1029         if (test_bit(RXRPC_CALL_ACK, &call->events)) {
1030                 _debug("send ACK: window: %d - %d { %lx }",
1031                        call->rx_data_eaten, call->ackr_win_top,
1032                        call->ackr_window[0]);
1033 
1034                 if (call->state > RXRPC_CALL_SERVER_ACK_REQUEST &&
1035                     call->ackr_reason != RXRPC_ACK_PING_RESPONSE) {
1036                         /* ACK by sending reply DATA packet in this state */
1037                         clear_bit(RXRPC_CALL_ACK, &call->events);
1038                         goto maybe_reschedule;
1039                 }
1040 
1041                 genbit = RXRPC_CALL_ACK;
1042 
1043                 acks = kzalloc(call->ackr_win_top - call->rx_data_eaten,
1044                                GFP_NOFS);
1045                 if (!acks)
1046                         goto no_mem;
1047 
1048                 //hdr.flags     = RXRPC_SLOW_START_OK;
1049                 ack.bufferSpace = htons(8);
1050                 ack.maxSkew     = 0;
1051                 ack.serial      = 0;
1052                 ack.reason      = 0;
1053 
1054                 spin_lock_bh(&call->lock);
1055                 ack.reason = call->ackr_reason;
1056                 ack.serial = call->ackr_serial;
1057                 ack.previousPacket = call->ackr_prev_seq;
1058                 ack.firstPacket = htonl(call->rx_data_eaten + 1);
1059 
1060                 ack.nAcks = 0;
1061                 for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
1062                         nbit = loop * BITS_PER_LONG;
1063                         for (bits = call->ackr_window[loop]; bits; bits >>= 1
1064                              ) {
1065                                 _debug("- l=%d n=%d b=%lx", loop, nbit, bits);
1066                                 if (bits & 1) {
1067                                         acks[nbit] = RXRPC_ACK_TYPE_ACK;
1068                                         ack.nAcks = nbit + 1;
1069                                 }
1070                                 nbit++;
1071                         }
1072                 }
1073                 call->ackr_reason = 0;
1074                 spin_unlock_bh(&call->lock);
1075 
1076                 pad = 0;
1077 
1078                 iov[1].iov_base = &ack;
1079                 iov[1].iov_len  = sizeof(ack);
1080                 iov[2].iov_base = acks;
1081                 iov[2].iov_len  = ack.nAcks;
1082                 iov[3].iov_base = &pad;
1083                 iov[3].iov_len  = 3;
1084                 iov[4].iov_base = &ackinfo;
1085                 iov[4].iov_len  = sizeof(ackinfo);
1086 
1087                 switch (ack.reason) {
1088                 case RXRPC_ACK_REQUESTED:
1089                 case RXRPC_ACK_DUPLICATE:
1090                 case RXRPC_ACK_OUT_OF_SEQUENCE:
1091                 case RXRPC_ACK_EXCEEDS_WINDOW:
1092                 case RXRPC_ACK_NOSPACE:
1093                 case RXRPC_ACK_PING:
1094                 case RXRPC_ACK_PING_RESPONSE:
1095                         goto send_ACK_with_skew;
1096                 case RXRPC_ACK_DELAY:
1097                 case RXRPC_ACK_IDLE:
1098                         goto send_ACK;
1099                 }
1100         }
1101 
1102         /* handle completion of security negotiations on an incoming
1103          * connection */
1104         if (test_and_clear_bit(RXRPC_CALL_SECURED, &call->events)) {
1105                 _debug("secured");
1106                 spin_lock_bh(&call->lock);
1107 
1108                 if (call->state == RXRPC_CALL_SERVER_SECURING) {
1109                         _debug("securing");
1110                         write_lock(&call->conn->lock);
1111                         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1112                             !test_bit(RXRPC_CALL_RELEASE, &call->events)) {
1113                                 _debug("not released");
1114                                 call->state = RXRPC_CALL_SERVER_ACCEPTING;
1115                                 list_move_tail(&call->accept_link,
1116                                                &call->socket->acceptq);
1117                         }
1118                         write_unlock(&call->conn->lock);
1119                         read_lock(&call->state_lock);
1120                         if (call->state < RXRPC_CALL_COMPLETE)
1121                                 set_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1122                         read_unlock(&call->state_lock);
1123                 }
1124 
1125                 spin_unlock_bh(&call->lock);
1126                 if (!test_bit(RXRPC_CALL_POST_ACCEPT, &call->events))
1127                         goto maybe_reschedule;
1128         }
1129 
1130         /* post a notification of an acceptable connection to the app */
1131         if (test_bit(RXRPC_CALL_POST_ACCEPT, &call->events)) {
1132                 _debug("post accept");
1133                 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NEW_CALL,
1134                                        0, false) < 0)
1135                         goto no_mem;
1136                 clear_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1137                 goto maybe_reschedule;
1138         }
1139 
1140         /* handle incoming call acceptance */
1141         if (test_and_clear_bit(RXRPC_CALL_ACCEPTED, &call->events)) {
1142                 _debug("accepted");
1143                 ASSERTCMP(call->rx_data_post, ==, 0);
1144                 call->rx_data_post = 1;
1145                 read_lock_bh(&call->state_lock);
1146                 if (call->state < RXRPC_CALL_COMPLETE)
1147                         set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
1148                 read_unlock_bh(&call->state_lock);
1149         }
1150 
1151         /* drain the out of sequence received packet queue into the packet Rx
1152          * queue */
1153         if (test_and_clear_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events)) {
1154                 while (call->rx_data_post == call->rx_first_oos)
1155                         if (rxrpc_drain_rx_oos_queue(call) < 0)
1156                                 break;
1157                 goto maybe_reschedule;
1158         }
1159 
1160         /* other events may have been raised since we started checking */
1161         goto maybe_reschedule;
1162 
1163 send_ACK_with_skew:
1164         ack.maxSkew = htons(atomic_read(&call->conn->hi_serial) -
1165                             ntohl(ack.serial));
1166 send_ACK:
1167         mtu = call->conn->trans->peer->if_mtu;
1168         mtu -= call->conn->trans->peer->hdrsize;
1169         ackinfo.maxMTU  = htonl(mtu);
1170         ackinfo.rwind   = htonl(32);
1171 
1172         /* permit the peer to send us jumbo packets if it wants to */
1173         ackinfo.rxMTU   = htonl(5692);
1174         ackinfo.jumbo_max = htonl(4);
1175 
1176         hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1177         _proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
1178                ntohl(hdr.serial),
1179                ntohs(ack.maxSkew),
1180                ntohl(ack.firstPacket),
1181                ntohl(ack.previousPacket),
1182                ntohl(ack.serial),
1183                rxrpc_acks[ack.reason],
1184                ack.nAcks);
1185 
1186         del_timer_sync(&call->ack_timer);
1187         if (ack.nAcks > 0)
1188                 set_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags);
1189         goto send_message_2;
1190 
1191 send_message:
1192         _debug("send message");
1193 
1194         hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1195         _proto("Tx %s %%%u", rxrpc_pkts[hdr.type], ntohl(hdr.serial));
1196 send_message_2:
1197 
1198         len = iov[0].iov_len;
1199         ioc = 1;
1200         if (iov[4].iov_len) {
1201                 ioc = 5;
1202                 len += iov[4].iov_len;
1203                 len += iov[3].iov_len;
1204                 len += iov[2].iov_len;
1205                 len += iov[1].iov_len;
1206         } else if (iov[3].iov_len) {
1207                 ioc = 4;
1208                 len += iov[3].iov_len;
1209                 len += iov[2].iov_len;
1210                 len += iov[1].iov_len;
1211         } else if (iov[2].iov_len) {
1212                 ioc = 3;
1213                 len += iov[2].iov_len;
1214                 len += iov[1].iov_len;
1215         } else if (iov[1].iov_len) {
1216                 ioc = 2;
1217                 len += iov[1].iov_len;
1218         }
1219 
1220         ret = kernel_sendmsg(call->conn->trans->local->socket,
1221                              &msg, iov, ioc, len);
1222         if (ret < 0) {
1223                 _debug("sendmsg failed: %d", ret);
1224                 read_lock_bh(&call->state_lock);
1225                 if (call->state < RXRPC_CALL_DEAD)
1226                         rxrpc_queue_call(call);
1227                 read_unlock_bh(&call->state_lock);
1228                 goto error;
1229         }
1230 
1231         switch (genbit) {
1232         case RXRPC_CALL_ABORT:
1233                 clear_bit(genbit, &call->events);
1234                 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
1235                 goto kill_ACKs;
1236 
1237         case RXRPC_CALL_ACK_FINAL:
1238                 write_lock_bh(&call->state_lock);
1239                 if (call->state == RXRPC_CALL_CLIENT_FINAL_ACK)
1240                         call->state = RXRPC_CALL_COMPLETE;
1241                 write_unlock_bh(&call->state_lock);
1242                 goto kill_ACKs;
1243 
1244         default:
1245                 clear_bit(genbit, &call->events);
1246                 switch (call->state) {
1247                 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
1248                 case RXRPC_CALL_CLIENT_RECV_REPLY:
1249                 case RXRPC_CALL_SERVER_RECV_REQUEST:
1250                 case RXRPC_CALL_SERVER_ACK_REQUEST:
1251                         _debug("start ACK timer");
1252                         rxrpc_propose_ACK(call, RXRPC_ACK_DELAY,
1253                                           call->ackr_serial, false);
1254                 default:
1255                         break;
1256                 }
1257                 goto maybe_reschedule;
1258         }
1259 
1260 kill_ACKs:
1261         del_timer_sync(&call->ack_timer);
1262         if (test_and_clear_bit(RXRPC_CALL_ACK_FINAL, &call->events))
1263                 rxrpc_put_call(call);
1264         clear_bit(RXRPC_CALL_ACK, &call->events);
1265 
1266 maybe_reschedule:
1267         if (call->events || !skb_queue_empty(&call->rx_queue)) {
1268                 read_lock_bh(&call->state_lock);
1269                 if (call->state < RXRPC_CALL_DEAD)
1270                         rxrpc_queue_call(call);
1271                 read_unlock_bh(&call->state_lock);
1272         }
1273 
1274         /* don't leave aborted connections on the accept queue */
1275         if (call->state >= RXRPC_CALL_COMPLETE &&
1276             !list_empty(&call->accept_link)) {
1277                 _debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
1278                        call, call->events, call->flags,
1279                        ntohl(call->conn->cid));
1280 
1281                 read_lock_bh(&call->state_lock);
1282                 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1283                     !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
1284                         rxrpc_queue_call(call);
1285                 read_unlock_bh(&call->state_lock);
1286         }
1287 
1288 error:
1289         clear_bit(RXRPC_CALL_PROC_BUSY, &call->flags);
1290         kfree(acks);
1291 
1292         /* because we don't want two CPUs both processing the work item for one
1293          * call at the same time, we use a flag to note when it's busy; however
1294          * this means there's a race between clearing the flag and setting the
1295          * work pending bit and the work item being processed again */
1296         if (call->events && !work_pending(&call->processor)) {
1297                 _debug("jumpstart %x", ntohl(call->conn->cid));
1298                 rxrpc_queue_call(call);
1299         }
1300 
1301         _leave("");
1302         return;
1303 
1304 no_mem:
1305         _debug("out of memory");
1306         goto maybe_reschedule;
1307 }
1308 

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