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/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 */
__rxrpc_propose_ACK(struct rxrpc_call * call,uint8_t ack_reason,__be32 serial,bool immediate)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 */
rxrpc_propose_ACK(struct rxrpc_call * call,uint8_t ack_reason,__be32 serial,bool immediate)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 */
rxrpc_set_resend(struct rxrpc_call * call,u8 resend,unsigned long resend_at)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 */
rxrpc_resend(struct rxrpc_call * call)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 */
rxrpc_resend_timer(struct rxrpc_call * call)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 */
rxrpc_process_soft_ACKs(struct rxrpc_call * call,struct rxrpc_ackpacket * ack,struct sk_buff * skb)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 */
rxrpc_rotate_tx_window(struct rxrpc_call * call,u32 hard)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 */
rxrpc_clear_tx_window(struct rxrpc_call * call)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 */
rxrpc_drain_rx_oos_queue(struct rxrpc_call * call)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 */
rxrpc_insert_oos_packet(struct rxrpc_call * call,struct sk_buff * skb)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 */
rxrpc_zap_tx_window(struct rxrpc_call * call)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 the extra information that may be appended to an ACK packet
547 */
rxrpc_extract_ackinfo(struct rxrpc_call * call,struct sk_buff * skb,unsigned latest,int nAcks)548 static void rxrpc_extract_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
549 unsigned latest, int nAcks)
550 {
551 struct rxrpc_ackinfo ackinfo;
552 struct rxrpc_peer *peer;
553 unsigned mtu;
554
555 if (skb_copy_bits(skb, nAcks + 3, &ackinfo, sizeof(ackinfo)) < 0) {
556 _leave(" [no ackinfo]");
557 return;
558 }
559
560 _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
561 latest,
562 ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU),
563 ntohl(ackinfo.rwind), ntohl(ackinfo.jumbo_max));
564
565 mtu = min(ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU));
566
567 peer = call->conn->trans->peer;
568 if (mtu < peer->maxdata) {
569 spin_lock_bh(&peer->lock);
570 peer->maxdata = mtu;
571 peer->mtu = mtu + peer->hdrsize;
572 spin_unlock_bh(&peer->lock);
573 _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
574 }
575 }
576
577 /*
578 * process packets in the reception queue
579 */
rxrpc_process_rx_queue(struct rxrpc_call * call,u32 * _abort_code)580 static int rxrpc_process_rx_queue(struct rxrpc_call *call,
581 u32 *_abort_code)
582 {
583 struct rxrpc_ackpacket ack;
584 struct rxrpc_skb_priv *sp;
585 struct sk_buff *skb;
586 bool post_ACK;
587 int latest;
588 u32 hard, tx;
589
590 _enter("");
591
592 process_further:
593 skb = skb_dequeue(&call->rx_queue);
594 if (!skb)
595 return -EAGAIN;
596
597 _net("deferred skb %p", skb);
598
599 sp = rxrpc_skb(skb);
600
601 _debug("process %s [st %d]", rxrpc_pkts[sp->hdr.type], call->state);
602
603 post_ACK = false;
604
605 switch (sp->hdr.type) {
606 /* data packets that wind up here have been received out of
607 * order, need security processing or are jumbo packets */
608 case RXRPC_PACKET_TYPE_DATA:
609 _proto("OOSQ DATA %%%u { #%u }",
610 ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
611
612 /* secured packets must be verified and possibly decrypted */
613 if (rxrpc_verify_packet(call, skb, _abort_code) < 0)
614 goto protocol_error;
615
616 rxrpc_insert_oos_packet(call, skb);
617 goto process_further;
618
619 /* partial ACK to process */
620 case RXRPC_PACKET_TYPE_ACK:
621 if (skb_copy_bits(skb, 0, &ack, sizeof(ack)) < 0) {
622 _debug("extraction failure");
623 goto protocol_error;
624 }
625 if (!skb_pull(skb, sizeof(ack)))
626 BUG();
627
628 latest = ntohl(sp->hdr.serial);
629 hard = ntohl(ack.firstPacket);
630 tx = atomic_read(&call->sequence);
631
632 _proto("Rx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
633 latest,
634 ntohs(ack.maxSkew),
635 hard,
636 ntohl(ack.previousPacket),
637 ntohl(ack.serial),
638 rxrpc_acks[ack.reason],
639 ack.nAcks);
640
641 rxrpc_extract_ackinfo(call, skb, latest, ack.nAcks);
642
643 if (ack.reason == RXRPC_ACK_PING) {
644 _proto("Rx ACK %%%u PING Request", latest);
645 rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
646 sp->hdr.serial, true);
647 }
648
649 /* discard any out-of-order or duplicate ACKs */
650 if (latest - call->acks_latest <= 0) {
651 _debug("discard ACK %d <= %d",
652 latest, call->acks_latest);
653 goto discard;
654 }
655 call->acks_latest = latest;
656
657 if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
658 call->state != RXRPC_CALL_CLIENT_AWAIT_REPLY &&
659 call->state != RXRPC_CALL_SERVER_SEND_REPLY &&
660 call->state != RXRPC_CALL_SERVER_AWAIT_ACK)
661 goto discard;
662
663 _debug("Tx=%d H=%u S=%d", tx, call->acks_hard, call->state);
664
665 if (hard > 0) {
666 if (hard - 1 > tx) {
667 _debug("hard-ACK'd packet %d not transmitted"
668 " (%d top)",
669 hard - 1, tx);
670 goto protocol_error;
671 }
672
673 if ((call->state == RXRPC_CALL_CLIENT_AWAIT_REPLY ||
674 call->state == RXRPC_CALL_SERVER_AWAIT_ACK) &&
675 hard > tx)
676 goto all_acked;
677
678 smp_rmb();
679 rxrpc_rotate_tx_window(call, hard - 1);
680 }
681
682 if (ack.nAcks > 0) {
683 if (hard - 1 + ack.nAcks > tx) {
684 _debug("soft-ACK'd packet %d+%d not"
685 " transmitted (%d top)",
686 hard - 1, ack.nAcks, tx);
687 goto protocol_error;
688 }
689
690 if (rxrpc_process_soft_ACKs(call, &ack, skb) < 0)
691 goto protocol_error;
692 }
693 goto discard;
694
695 /* complete ACK to process */
696 case RXRPC_PACKET_TYPE_ACKALL:
697 goto all_acked;
698
699 /* abort and busy are handled elsewhere */
700 case RXRPC_PACKET_TYPE_BUSY:
701 case RXRPC_PACKET_TYPE_ABORT:
702 BUG();
703
704 /* connection level events - also handled elsewhere */
705 case RXRPC_PACKET_TYPE_CHALLENGE:
706 case RXRPC_PACKET_TYPE_RESPONSE:
707 case RXRPC_PACKET_TYPE_DEBUG:
708 BUG();
709 }
710
711 /* if we've had a hard ACK that covers all the packets we've sent, then
712 * that ends that phase of the operation */
713 all_acked:
714 write_lock_bh(&call->state_lock);
715 _debug("ack all %d", call->state);
716
717 switch (call->state) {
718 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
719 call->state = RXRPC_CALL_CLIENT_RECV_REPLY;
720 break;
721 case RXRPC_CALL_SERVER_AWAIT_ACK:
722 _debug("srv complete");
723 call->state = RXRPC_CALL_COMPLETE;
724 post_ACK = true;
725 break;
726 case RXRPC_CALL_CLIENT_SEND_REQUEST:
727 case RXRPC_CALL_SERVER_RECV_REQUEST:
728 goto protocol_error_unlock; /* can't occur yet */
729 default:
730 write_unlock_bh(&call->state_lock);
731 goto discard; /* assume packet left over from earlier phase */
732 }
733
734 write_unlock_bh(&call->state_lock);
735
736 /* if all the packets we sent are hard-ACK'd, then we can discard
737 * whatever we've got left */
738 _debug("clear Tx %d",
739 CIRC_CNT(call->acks_head, call->acks_tail, call->acks_winsz));
740
741 del_timer_sync(&call->resend_timer);
742 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
743 clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
744
745 if (call->acks_window)
746 rxrpc_zap_tx_window(call);
747
748 if (post_ACK) {
749 /* post the final ACK message for userspace to pick up */
750 _debug("post ACK");
751 skb->mark = RXRPC_SKB_MARK_FINAL_ACK;
752 sp->call = call;
753 rxrpc_get_call(call);
754 spin_lock_bh(&call->lock);
755 if (rxrpc_queue_rcv_skb(call, skb, true, true) < 0)
756 BUG();
757 spin_unlock_bh(&call->lock);
758 goto process_further;
759 }
760
761 discard:
762 rxrpc_free_skb(skb);
763 goto process_further;
764
765 protocol_error_unlock:
766 write_unlock_bh(&call->state_lock);
767 protocol_error:
768 rxrpc_free_skb(skb);
769 _leave(" = -EPROTO");
770 return -EPROTO;
771 }
772
773 /*
774 * post a message to the socket Rx queue for recvmsg() to pick up
775 */
rxrpc_post_message(struct rxrpc_call * call,u32 mark,u32 error,bool fatal)776 static int rxrpc_post_message(struct rxrpc_call *call, u32 mark, u32 error,
777 bool fatal)
778 {
779 struct rxrpc_skb_priv *sp;
780 struct sk_buff *skb;
781 int ret;
782
783 _enter("{%d,%lx},%u,%u,%d",
784 call->debug_id, call->flags, mark, error, fatal);
785
786 /* remove timers and things for fatal messages */
787 if (fatal) {
788 del_timer_sync(&call->resend_timer);
789 del_timer_sync(&call->ack_timer);
790 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
791 }
792
793 if (mark != RXRPC_SKB_MARK_NEW_CALL &&
794 !test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
795 _leave("[no userid]");
796 return 0;
797 }
798
799 if (!test_bit(RXRPC_CALL_TERMINAL_MSG, &call->flags)) {
800 skb = alloc_skb(0, GFP_NOFS);
801 if (!skb)
802 return -ENOMEM;
803
804 rxrpc_new_skb(skb);
805
806 skb->mark = mark;
807
808 sp = rxrpc_skb(skb);
809 memset(sp, 0, sizeof(*sp));
810 sp->error = error;
811 sp->call = call;
812 rxrpc_get_call(call);
813
814 spin_lock_bh(&call->lock);
815 ret = rxrpc_queue_rcv_skb(call, skb, true, fatal);
816 spin_unlock_bh(&call->lock);
817 BUG_ON(ret < 0);
818 }
819
820 return 0;
821 }
822
823 /*
824 * handle background processing of incoming call packets and ACK / abort
825 * generation
826 */
rxrpc_process_call(struct work_struct * work)827 void rxrpc_process_call(struct work_struct *work)
828 {
829 struct rxrpc_call *call =
830 container_of(work, struct rxrpc_call, processor);
831 struct rxrpc_ackpacket ack;
832 struct rxrpc_ackinfo ackinfo;
833 struct rxrpc_header hdr;
834 struct msghdr msg;
835 struct kvec iov[5];
836 unsigned long bits;
837 __be32 data, pad;
838 size_t len;
839 int genbit, loop, nbit, ioc, ret, mtu;
840 u32 abort_code = RX_PROTOCOL_ERROR;
841 u8 *acks = NULL;
842
843 //printk("\n--------------------\n");
844 _enter("{%d,%s,%lx} [%lu]",
845 call->debug_id, rxrpc_call_states[call->state], call->events,
846 (jiffies - call->creation_jif) / (HZ / 10));
847
848 if (test_and_set_bit(RXRPC_CALL_PROC_BUSY, &call->flags)) {
849 _debug("XXXXXXXXXXXXX RUNNING ON MULTIPLE CPUS XXXXXXXXXXXXX");
850 return;
851 }
852
853 /* there's a good chance we're going to have to send a message, so set
854 * one up in advance */
855 msg.msg_name = &call->conn->trans->peer->srx.transport.sin;
856 msg.msg_namelen = sizeof(call->conn->trans->peer->srx.transport.sin);
857 msg.msg_control = NULL;
858 msg.msg_controllen = 0;
859 msg.msg_flags = 0;
860
861 hdr.epoch = call->conn->epoch;
862 hdr.cid = call->cid;
863 hdr.callNumber = call->call_id;
864 hdr.seq = 0;
865 hdr.type = RXRPC_PACKET_TYPE_ACK;
866 hdr.flags = call->conn->out_clientflag;
867 hdr.userStatus = 0;
868 hdr.securityIndex = call->conn->security_ix;
869 hdr._rsvd = 0;
870 hdr.serviceId = call->conn->service_id;
871
872 memset(iov, 0, sizeof(iov));
873 iov[0].iov_base = &hdr;
874 iov[0].iov_len = sizeof(hdr);
875
876 /* deal with events of a final nature */
877 if (test_bit(RXRPC_CALL_RELEASE, &call->events)) {
878 rxrpc_release_call(call);
879 clear_bit(RXRPC_CALL_RELEASE, &call->events);
880 }
881
882 if (test_bit(RXRPC_CALL_RCVD_ERROR, &call->events)) {
883 int error;
884
885 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
886 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
887 clear_bit(RXRPC_CALL_ABORT, &call->events);
888
889 error = call->conn->trans->peer->net_error;
890 _debug("post net error %d", error);
891
892 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NET_ERROR,
893 error, true) < 0)
894 goto no_mem;
895 clear_bit(RXRPC_CALL_RCVD_ERROR, &call->events);
896 goto kill_ACKs;
897 }
898
899 if (test_bit(RXRPC_CALL_CONN_ABORT, &call->events)) {
900 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
901
902 clear_bit(RXRPC_CALL_REJECT_BUSY, &call->events);
903 clear_bit(RXRPC_CALL_ABORT, &call->events);
904
905 _debug("post conn abort");
906
907 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
908 call->conn->error, true) < 0)
909 goto no_mem;
910 clear_bit(RXRPC_CALL_CONN_ABORT, &call->events);
911 goto kill_ACKs;
912 }
913
914 if (test_bit(RXRPC_CALL_REJECT_BUSY, &call->events)) {
915 hdr.type = RXRPC_PACKET_TYPE_BUSY;
916 genbit = RXRPC_CALL_REJECT_BUSY;
917 goto send_message;
918 }
919
920 if (test_bit(RXRPC_CALL_ABORT, &call->events)) {
921 ASSERTCMP(call->state, >, RXRPC_CALL_COMPLETE);
922
923 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
924 ECONNABORTED, true) < 0)
925 goto no_mem;
926 hdr.type = RXRPC_PACKET_TYPE_ABORT;
927 data = htonl(call->abort_code);
928 iov[1].iov_base = &data;
929 iov[1].iov_len = sizeof(data);
930 genbit = RXRPC_CALL_ABORT;
931 goto send_message;
932 }
933
934 if (test_bit(RXRPC_CALL_ACK_FINAL, &call->events)) {
935 genbit = RXRPC_CALL_ACK_FINAL;
936
937 ack.bufferSpace = htons(8);
938 ack.maxSkew = 0;
939 ack.serial = 0;
940 ack.reason = RXRPC_ACK_IDLE;
941 ack.nAcks = 0;
942 call->ackr_reason = 0;
943
944 spin_lock_bh(&call->lock);
945 ack.serial = call->ackr_serial;
946 ack.previousPacket = call->ackr_prev_seq;
947 ack.firstPacket = htonl(call->rx_data_eaten + 1);
948 spin_unlock_bh(&call->lock);
949
950 pad = 0;
951
952 iov[1].iov_base = &ack;
953 iov[1].iov_len = sizeof(ack);
954 iov[2].iov_base = &pad;
955 iov[2].iov_len = 3;
956 iov[3].iov_base = &ackinfo;
957 iov[3].iov_len = sizeof(ackinfo);
958 goto send_ACK;
959 }
960
961 if (call->events & ((1 << RXRPC_CALL_RCVD_BUSY) |
962 (1 << RXRPC_CALL_RCVD_ABORT))
963 ) {
964 u32 mark;
965
966 if (test_bit(RXRPC_CALL_RCVD_ABORT, &call->events))
967 mark = RXRPC_SKB_MARK_REMOTE_ABORT;
968 else
969 mark = RXRPC_SKB_MARK_BUSY;
970
971 _debug("post abort/busy");
972 rxrpc_clear_tx_window(call);
973 if (rxrpc_post_message(call, mark, ECONNABORTED, true) < 0)
974 goto no_mem;
975
976 clear_bit(RXRPC_CALL_RCVD_BUSY, &call->events);
977 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
978 goto kill_ACKs;
979 }
980
981 if (test_and_clear_bit(RXRPC_CALL_RCVD_ACKALL, &call->events)) {
982 _debug("do implicit ackall");
983 rxrpc_clear_tx_window(call);
984 }
985
986 if (test_bit(RXRPC_CALL_LIFE_TIMER, &call->events)) {
987 write_lock_bh(&call->state_lock);
988 if (call->state <= RXRPC_CALL_COMPLETE) {
989 call->state = RXRPC_CALL_LOCALLY_ABORTED;
990 call->abort_code = RX_CALL_TIMEOUT;
991 set_bit(RXRPC_CALL_ABORT, &call->events);
992 }
993 write_unlock_bh(&call->state_lock);
994
995 _debug("post timeout");
996 if (rxrpc_post_message(call, RXRPC_SKB_MARK_LOCAL_ERROR,
997 ETIME, true) < 0)
998 goto no_mem;
999
1000 clear_bit(RXRPC_CALL_LIFE_TIMER, &call->events);
1001 goto kill_ACKs;
1002 }
1003
1004 /* deal with assorted inbound messages */
1005 if (!skb_queue_empty(&call->rx_queue)) {
1006 switch (rxrpc_process_rx_queue(call, &abort_code)) {
1007 case 0:
1008 case -EAGAIN:
1009 break;
1010 case -ENOMEM:
1011 goto no_mem;
1012 case -EKEYEXPIRED:
1013 case -EKEYREJECTED:
1014 case -EPROTO:
1015 rxrpc_abort_call(call, abort_code);
1016 goto kill_ACKs;
1017 }
1018 }
1019
1020 /* handle resending */
1021 if (test_and_clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
1022 rxrpc_resend_timer(call);
1023 if (test_and_clear_bit(RXRPC_CALL_RESEND, &call->events))
1024 rxrpc_resend(call);
1025
1026 /* consider sending an ordinary ACK */
1027 if (test_bit(RXRPC_CALL_ACK, &call->events)) {
1028 _debug("send ACK: window: %d - %d { %lx }",
1029 call->rx_data_eaten, call->ackr_win_top,
1030 call->ackr_window[0]);
1031
1032 if (call->state > RXRPC_CALL_SERVER_ACK_REQUEST &&
1033 call->ackr_reason != RXRPC_ACK_PING_RESPONSE) {
1034 /* ACK by sending reply DATA packet in this state */
1035 clear_bit(RXRPC_CALL_ACK, &call->events);
1036 goto maybe_reschedule;
1037 }
1038
1039 genbit = RXRPC_CALL_ACK;
1040
1041 acks = kzalloc(call->ackr_win_top - call->rx_data_eaten,
1042 GFP_NOFS);
1043 if (!acks)
1044 goto no_mem;
1045
1046 //hdr.flags = RXRPC_SLOW_START_OK;
1047 ack.bufferSpace = htons(8);
1048 ack.maxSkew = 0;
1049 ack.serial = 0;
1050 ack.reason = 0;
1051
1052 spin_lock_bh(&call->lock);
1053 ack.reason = call->ackr_reason;
1054 ack.serial = call->ackr_serial;
1055 ack.previousPacket = call->ackr_prev_seq;
1056 ack.firstPacket = htonl(call->rx_data_eaten + 1);
1057
1058 ack.nAcks = 0;
1059 for (loop = 0; loop < RXRPC_ACKR_WINDOW_ASZ; loop++) {
1060 nbit = loop * BITS_PER_LONG;
1061 for (bits = call->ackr_window[loop]; bits; bits >>= 1
1062 ) {
1063 _debug("- l=%d n=%d b=%lx", loop, nbit, bits);
1064 if (bits & 1) {
1065 acks[nbit] = RXRPC_ACK_TYPE_ACK;
1066 ack.nAcks = nbit + 1;
1067 }
1068 nbit++;
1069 }
1070 }
1071 call->ackr_reason = 0;
1072 spin_unlock_bh(&call->lock);
1073
1074 pad = 0;
1075
1076 iov[1].iov_base = &ack;
1077 iov[1].iov_len = sizeof(ack);
1078 iov[2].iov_base = acks;
1079 iov[2].iov_len = ack.nAcks;
1080 iov[3].iov_base = &pad;
1081 iov[3].iov_len = 3;
1082 iov[4].iov_base = &ackinfo;
1083 iov[4].iov_len = sizeof(ackinfo);
1084
1085 switch (ack.reason) {
1086 case RXRPC_ACK_REQUESTED:
1087 case RXRPC_ACK_DUPLICATE:
1088 case RXRPC_ACK_OUT_OF_SEQUENCE:
1089 case RXRPC_ACK_EXCEEDS_WINDOW:
1090 case RXRPC_ACK_NOSPACE:
1091 case RXRPC_ACK_PING:
1092 case RXRPC_ACK_PING_RESPONSE:
1093 goto send_ACK_with_skew;
1094 case RXRPC_ACK_DELAY:
1095 case RXRPC_ACK_IDLE:
1096 goto send_ACK;
1097 }
1098 }
1099
1100 /* handle completion of security negotiations on an incoming
1101 * connection */
1102 if (test_and_clear_bit(RXRPC_CALL_SECURED, &call->events)) {
1103 _debug("secured");
1104 spin_lock_bh(&call->lock);
1105
1106 if (call->state == RXRPC_CALL_SERVER_SECURING) {
1107 _debug("securing");
1108 write_lock(&call->conn->lock);
1109 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1110 !test_bit(RXRPC_CALL_RELEASE, &call->events)) {
1111 _debug("not released");
1112 call->state = RXRPC_CALL_SERVER_ACCEPTING;
1113 list_move_tail(&call->accept_link,
1114 &call->socket->acceptq);
1115 }
1116 write_unlock(&call->conn->lock);
1117 read_lock(&call->state_lock);
1118 if (call->state < RXRPC_CALL_COMPLETE)
1119 set_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1120 read_unlock(&call->state_lock);
1121 }
1122
1123 spin_unlock_bh(&call->lock);
1124 if (!test_bit(RXRPC_CALL_POST_ACCEPT, &call->events))
1125 goto maybe_reschedule;
1126 }
1127
1128 /* post a notification of an acceptable connection to the app */
1129 if (test_bit(RXRPC_CALL_POST_ACCEPT, &call->events)) {
1130 _debug("post accept");
1131 if (rxrpc_post_message(call, RXRPC_SKB_MARK_NEW_CALL,
1132 0, false) < 0)
1133 goto no_mem;
1134 clear_bit(RXRPC_CALL_POST_ACCEPT, &call->events);
1135 goto maybe_reschedule;
1136 }
1137
1138 /* handle incoming call acceptance */
1139 if (test_and_clear_bit(RXRPC_CALL_ACCEPTED, &call->events)) {
1140 _debug("accepted");
1141 ASSERTCMP(call->rx_data_post, ==, 0);
1142 call->rx_data_post = 1;
1143 read_lock_bh(&call->state_lock);
1144 if (call->state < RXRPC_CALL_COMPLETE)
1145 set_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events);
1146 read_unlock_bh(&call->state_lock);
1147 }
1148
1149 /* drain the out of sequence received packet queue into the packet Rx
1150 * queue */
1151 if (test_and_clear_bit(RXRPC_CALL_DRAIN_RX_OOS, &call->events)) {
1152 while (call->rx_data_post == call->rx_first_oos)
1153 if (rxrpc_drain_rx_oos_queue(call) < 0)
1154 break;
1155 goto maybe_reschedule;
1156 }
1157
1158 /* other events may have been raised since we started checking */
1159 goto maybe_reschedule;
1160
1161 send_ACK_with_skew:
1162 ack.maxSkew = htons(atomic_read(&call->conn->hi_serial) -
1163 ntohl(ack.serial));
1164 send_ACK:
1165 mtu = call->conn->trans->peer->if_mtu;
1166 mtu -= call->conn->trans->peer->hdrsize;
1167 ackinfo.maxMTU = htonl(mtu);
1168 ackinfo.rwind = htonl(32);
1169
1170 /* permit the peer to send us jumbo packets if it wants to */
1171 ackinfo.rxMTU = htonl(5692);
1172 ackinfo.jumbo_max = htonl(4);
1173
1174 hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1175 _proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
1176 ntohl(hdr.serial),
1177 ntohs(ack.maxSkew),
1178 ntohl(ack.firstPacket),
1179 ntohl(ack.previousPacket),
1180 ntohl(ack.serial),
1181 rxrpc_acks[ack.reason],
1182 ack.nAcks);
1183
1184 del_timer_sync(&call->ack_timer);
1185 if (ack.nAcks > 0)
1186 set_bit(RXRPC_CALL_TX_SOFT_ACK, &call->flags);
1187 goto send_message_2;
1188
1189 send_message:
1190 _debug("send message");
1191
1192 hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
1193 _proto("Tx %s %%%u", rxrpc_pkts[hdr.type], ntohl(hdr.serial));
1194 send_message_2:
1195
1196 len = iov[0].iov_len;
1197 ioc = 1;
1198 if (iov[4].iov_len) {
1199 ioc = 5;
1200 len += iov[4].iov_len;
1201 len += iov[3].iov_len;
1202 len += iov[2].iov_len;
1203 len += iov[1].iov_len;
1204 } else if (iov[3].iov_len) {
1205 ioc = 4;
1206 len += iov[3].iov_len;
1207 len += iov[2].iov_len;
1208 len += iov[1].iov_len;
1209 } else if (iov[2].iov_len) {
1210 ioc = 3;
1211 len += iov[2].iov_len;
1212 len += iov[1].iov_len;
1213 } else if (iov[1].iov_len) {
1214 ioc = 2;
1215 len += iov[1].iov_len;
1216 }
1217
1218 ret = kernel_sendmsg(call->conn->trans->local->socket,
1219 &msg, iov, ioc, len);
1220 if (ret < 0) {
1221 _debug("sendmsg failed: %d", ret);
1222 read_lock_bh(&call->state_lock);
1223 if (call->state < RXRPC_CALL_DEAD)
1224 rxrpc_queue_call(call);
1225 read_unlock_bh(&call->state_lock);
1226 goto error;
1227 }
1228
1229 switch (genbit) {
1230 case RXRPC_CALL_ABORT:
1231 clear_bit(genbit, &call->events);
1232 clear_bit(RXRPC_CALL_RCVD_ABORT, &call->events);
1233 goto kill_ACKs;
1234
1235 case RXRPC_CALL_ACK_FINAL:
1236 write_lock_bh(&call->state_lock);
1237 if (call->state == RXRPC_CALL_CLIENT_FINAL_ACK)
1238 call->state = RXRPC_CALL_COMPLETE;
1239 write_unlock_bh(&call->state_lock);
1240 goto kill_ACKs;
1241
1242 default:
1243 clear_bit(genbit, &call->events);
1244 switch (call->state) {
1245 case RXRPC_CALL_CLIENT_AWAIT_REPLY:
1246 case RXRPC_CALL_CLIENT_RECV_REPLY:
1247 case RXRPC_CALL_SERVER_RECV_REQUEST:
1248 case RXRPC_CALL_SERVER_ACK_REQUEST:
1249 _debug("start ACK timer");
1250 rxrpc_propose_ACK(call, RXRPC_ACK_DELAY,
1251 call->ackr_serial, false);
1252 default:
1253 break;
1254 }
1255 goto maybe_reschedule;
1256 }
1257
1258 kill_ACKs:
1259 del_timer_sync(&call->ack_timer);
1260 if (test_and_clear_bit(RXRPC_CALL_ACK_FINAL, &call->events))
1261 rxrpc_put_call(call);
1262 clear_bit(RXRPC_CALL_ACK, &call->events);
1263
1264 maybe_reschedule:
1265 if (call->events || !skb_queue_empty(&call->rx_queue)) {
1266 read_lock_bh(&call->state_lock);
1267 if (call->state < RXRPC_CALL_DEAD)
1268 rxrpc_queue_call(call);
1269 read_unlock_bh(&call->state_lock);
1270 }
1271
1272 /* don't leave aborted connections on the accept queue */
1273 if (call->state >= RXRPC_CALL_COMPLETE &&
1274 !list_empty(&call->accept_link)) {
1275 _debug("X unlinking once-pending call %p { e=%lx f=%lx c=%x }",
1276 call, call->events, call->flags,
1277 ntohl(call->conn->cid));
1278
1279 read_lock_bh(&call->state_lock);
1280 if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
1281 !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
1282 rxrpc_queue_call(call);
1283 read_unlock_bh(&call->state_lock);
1284 }
1285
1286 error:
1287 clear_bit(RXRPC_CALL_PROC_BUSY, &call->flags);
1288 kfree(acks);
1289
1290 /* because we don't want two CPUs both processing the work item for one
1291 * call at the same time, we use a flag to note when it's busy; however
1292 * this means there's a race between clearing the flag and setting the
1293 * work pending bit and the work item being processed again */
1294 if (call->events && !work_pending(&call->processor)) {
1295 _debug("jumpstart %x", ntohl(call->conn->cid));
1296 rxrpc_queue_call(call);
1297 }
1298
1299 _leave("");
1300 return;
1301
1302 no_mem:
1303 _debug("out of memory");
1304 goto maybe_reschedule;
1305 }
1306