1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Client connection-specific management code.
3 *
4 * Copyright (C) 2016, 2020 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 *
7 * Client connections need to be cached for a little while after they've made a
8 * call so as to handle retransmitted DATA packets in case the server didn't
9 * receive the final ACK or terminating ABORT we sent it.
10 *
11 * There are flags of relevance to the cache:
12 *
13 * (2) DONT_REUSE - The connection should be discarded as soon as possible and
14 * should not be reused. This is set when an exclusive connection is used
15 * or a call ID counter overflows.
16 *
17 * The caching state may only be changed if the cache lock is held.
18 *
19 * There are two idle client connection expiry durations. If the total number
20 * of connections is below the reap threshold, we use the normal duration; if
21 * it's above, we use the fast duration.
22 */
23
24#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25
26#include <linux/slab.h>
27#include <linux/idr.h>
28#include <linux/timer.h>
29#include <linux/sched/signal.h>
30
31#include "ar-internal.h"
32
33__read_mostly unsigned int rxrpc_reap_client_connections = 900;
34__read_mostly unsigned long rxrpc_conn_idle_client_expiry = 2 * 60 * HZ;
35__read_mostly unsigned long rxrpc_conn_idle_client_fast_expiry = 2 * HZ;
36
37static void rxrpc_activate_bundle(struct rxrpc_bundle *bundle)
38{
39 atomic_inc(v: &bundle->active);
40}
41
42/*
43 * Release a connection ID for a client connection.
44 */
45static void rxrpc_put_client_connection_id(struct rxrpc_local *local,
46 struct rxrpc_connection *conn)
47{
48 idr_remove(&local->conn_ids, id: conn->proto.cid >> RXRPC_CIDSHIFT);
49}
50
51/*
52 * Destroy the client connection ID tree.
53 */
54static void rxrpc_destroy_client_conn_ids(struct rxrpc_local *local)
55{
56 struct rxrpc_connection *conn;
57 int id;
58
59 if (!idr_is_empty(idr: &local->conn_ids)) {
60 idr_for_each_entry(&local->conn_ids, conn, id) {
61 pr_err("AF_RXRPC: Leaked client conn %p {%d}\n",
62 conn, refcount_read(&conn->ref));
63 }
64 BUG();
65 }
66
67 idr_destroy(&local->conn_ids);
68}
69
70/*
71 * Allocate a connection bundle.
72 */
73static struct rxrpc_bundle *rxrpc_alloc_bundle(struct rxrpc_call *call,
74 gfp_t gfp)
75{
76 static atomic_t rxrpc_bundle_id;
77 struct rxrpc_bundle *bundle;
78
79 bundle = kzalloc(sizeof(*bundle), gfp);
80 if (bundle) {
81 bundle->local = call->local;
82 bundle->peer = rxrpc_get_peer(call->peer, rxrpc_peer_get_bundle);
83 bundle->key = key_get(key: call->key);
84 bundle->security = call->security;
85 bundle->exclusive = test_bit(RXRPC_CALL_EXCLUSIVE, &call->flags);
86 bundle->upgrade = test_bit(RXRPC_CALL_UPGRADE, &call->flags);
87 bundle->service_id = call->dest_srx.srx_service;
88 bundle->security_level = call->security_level;
89 bundle->debug_id = atomic_inc_return(v: &rxrpc_bundle_id);
90 refcount_set(r: &bundle->ref, n: 1);
91 atomic_set(v: &bundle->active, i: 1);
92 INIT_LIST_HEAD(list: &bundle->waiting_calls);
93 trace_rxrpc_bundle(bundle_debug_id: bundle->debug_id, ref: 1, why: rxrpc_bundle_new);
94
95 write_lock(&bundle->local->rxnet->conn_lock);
96 list_add_tail(new: &bundle->proc_link, head: &bundle->local->rxnet->bundle_proc_list);
97 write_unlock(&bundle->local->rxnet->conn_lock);
98 }
99 return bundle;
100}
101
102struct rxrpc_bundle *rxrpc_get_bundle(struct rxrpc_bundle *bundle,
103 enum rxrpc_bundle_trace why)
104{
105 int r;
106
107 __refcount_inc(r: &bundle->ref, oldp: &r);
108 trace_rxrpc_bundle(bundle_debug_id: bundle->debug_id, ref: r + 1, why);
109 return bundle;
110}
111
112static void rxrpc_free_bundle(struct rxrpc_bundle *bundle)
113{
114 trace_rxrpc_bundle(bundle_debug_id: bundle->debug_id, ref: refcount_read(r: &bundle->ref),
115 why: rxrpc_bundle_free);
116 write_lock(&bundle->local->rxnet->conn_lock);
117 list_del(entry: &bundle->proc_link);
118 write_unlock(&bundle->local->rxnet->conn_lock);
119 rxrpc_put_peer(bundle->peer, rxrpc_peer_put_bundle);
120 key_put(key: bundle->key);
121 kfree(objp: bundle);
122}
123
124void rxrpc_put_bundle(struct rxrpc_bundle *bundle, enum rxrpc_bundle_trace why)
125{
126 unsigned int id;
127 bool dead;
128 int r;
129
130 if (bundle) {
131 id = bundle->debug_id;
132 dead = __refcount_dec_and_test(r: &bundle->ref, oldp: &r);
133 trace_rxrpc_bundle(bundle_debug_id: id, ref: r - 1, why);
134 if (dead)
135 rxrpc_free_bundle(bundle);
136 }
137}
138
139/*
140 * Get rid of outstanding client connection preallocations when a local
141 * endpoint is destroyed.
142 */
143void rxrpc_purge_client_connections(struct rxrpc_local *local)
144{
145 rxrpc_destroy_client_conn_ids(local);
146}
147
148/*
149 * Allocate a client connection.
150 */
151static struct rxrpc_connection *
152rxrpc_alloc_client_connection(struct rxrpc_bundle *bundle)
153{
154 struct rxrpc_connection *conn;
155 struct rxrpc_local *local = bundle->local;
156 struct rxrpc_net *rxnet = local->rxnet;
157 int id;
158
159 _enter("");
160
161 conn = rxrpc_alloc_connection(rxnet, GFP_ATOMIC | __GFP_NOWARN);
162 if (!conn)
163 return ERR_PTR(error: -ENOMEM);
164
165 id = idr_alloc_cyclic(&local->conn_ids, ptr: conn, start: 1, end: 0x40000000,
166 GFP_ATOMIC | __GFP_NOWARN);
167 if (id < 0) {
168 kfree(objp: conn);
169 return ERR_PTR(error: id);
170 }
171
172 refcount_set(r: &conn->ref, n: 1);
173 conn->proto.cid = id << RXRPC_CIDSHIFT;
174 conn->proto.epoch = local->rxnet->epoch;
175 conn->out_clientflag = RXRPC_CLIENT_INITIATED;
176 conn->bundle = rxrpc_get_bundle(bundle, why: rxrpc_bundle_get_client_conn);
177 conn->local = rxrpc_get_local(bundle->local, rxrpc_local_get_client_conn);
178 conn->peer = rxrpc_get_peer(bundle->peer, rxrpc_peer_get_client_conn);
179 conn->key = key_get(key: bundle->key);
180 conn->security = bundle->security;
181 conn->exclusive = bundle->exclusive;
182 conn->upgrade = bundle->upgrade;
183 conn->orig_service_id = bundle->service_id;
184 conn->security_level = bundle->security_level;
185 conn->state = RXRPC_CONN_CLIENT_UNSECURED;
186 conn->service_id = conn->orig_service_id;
187
188 if (conn->security == &rxrpc_no_security)
189 conn->state = RXRPC_CONN_CLIENT;
190
191 atomic_inc(v: &rxnet->nr_conns);
192 write_lock(&rxnet->conn_lock);
193 list_add_tail(new: &conn->proc_link, head: &rxnet->conn_proc_list);
194 write_unlock(&rxnet->conn_lock);
195
196 rxrpc_see_connection(conn, rxrpc_conn_new_client);
197
198 atomic_inc(v: &rxnet->nr_client_conns);
199 trace_rxrpc_client(conn, channel: -1, op: rxrpc_client_alloc);
200 return conn;
201}
202
203/*
204 * Determine if a connection may be reused.
205 */
206static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn)
207{
208 struct rxrpc_net *rxnet;
209 int id_cursor, id, distance, limit;
210
211 if (!conn)
212 goto dont_reuse;
213
214 rxnet = conn->rxnet;
215 if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags))
216 goto dont_reuse;
217
218 if ((conn->state != RXRPC_CONN_CLIENT_UNSECURED &&
219 conn->state != RXRPC_CONN_CLIENT) ||
220 conn->proto.epoch != rxnet->epoch)
221 goto mark_dont_reuse;
222
223 /* The IDR tree gets very expensive on memory if the connection IDs are
224 * widely scattered throughout the number space, so we shall want to
225 * kill off connections that, say, have an ID more than about four
226 * times the maximum number of client conns away from the current
227 * allocation point to try and keep the IDs concentrated.
228 */
229 id_cursor = idr_get_cursor(idr: &conn->local->conn_ids);
230 id = conn->proto.cid >> RXRPC_CIDSHIFT;
231 distance = id - id_cursor;
232 if (distance < 0)
233 distance = -distance;
234 limit = umax(atomic_read(&rxnet->nr_conns) * 4, 1024);
235 if (distance > limit)
236 goto mark_dont_reuse;
237
238 return true;
239
240mark_dont_reuse:
241 set_bit(nr: RXRPC_CONN_DONT_REUSE, addr: &conn->flags);
242dont_reuse:
243 return false;
244}
245
246/*
247 * Look up the conn bundle that matches the connection parameters, adding it if
248 * it doesn't yet exist.
249 */
250int rxrpc_look_up_bundle(struct rxrpc_call *call, gfp_t gfp)
251{
252 struct rxrpc_bundle *bundle, *candidate;
253 struct rxrpc_local *local = call->local;
254 struct rb_node *p, **pp, *parent;
255 long diff;
256 bool upgrade = test_bit(RXRPC_CALL_UPGRADE, &call->flags);
257
258 _enter("{%px,%x,%u,%u}",
259 call->peer, key_serial(call->key), call->security_level,
260 upgrade);
261
262 if (test_bit(RXRPC_CALL_EXCLUSIVE, &call->flags)) {
263 call->bundle = rxrpc_alloc_bundle(call, gfp);
264 return call->bundle ? 0 : -ENOMEM;
265 }
266
267 /* First, see if the bundle is already there. */
268 _debug("search 1");
269 spin_lock(lock: &local->client_bundles_lock);
270 p = local->client_bundles.rb_node;
271 while (p) {
272 bundle = rb_entry(p, struct rxrpc_bundle, local_node);
273
274#define cmp(X, Y) ((long)(X) - (long)(Y))
275 diff = (cmp(bundle->peer, call->peer) ?:
276 cmp(bundle->key, call->key) ?:
277 cmp(bundle->security_level, call->security_level) ?:
278 cmp(bundle->upgrade, upgrade));
279#undef cmp
280 if (diff < 0)
281 p = p->rb_left;
282 else if (diff > 0)
283 p = p->rb_right;
284 else
285 goto found_bundle;
286 }
287 spin_unlock(lock: &local->client_bundles_lock);
288 _debug("not found");
289
290 /* It wasn't. We need to add one. */
291 candidate = rxrpc_alloc_bundle(call, gfp);
292 if (!candidate)
293 return -ENOMEM;
294
295 _debug("search 2");
296 spin_lock(lock: &local->client_bundles_lock);
297 pp = &local->client_bundles.rb_node;
298 parent = NULL;
299 while (*pp) {
300 parent = *pp;
301 bundle = rb_entry(parent, struct rxrpc_bundle, local_node);
302
303#define cmp(X, Y) ((long)(X) - (long)(Y))
304 diff = (cmp(bundle->peer, call->peer) ?:
305 cmp(bundle->key, call->key) ?:
306 cmp(bundle->security_level, call->security_level) ?:
307 cmp(bundle->upgrade, upgrade));
308#undef cmp
309 if (diff < 0)
310 pp = &(*pp)->rb_left;
311 else if (diff > 0)
312 pp = &(*pp)->rb_right;
313 else
314 goto found_bundle_free;
315 }
316
317 _debug("new bundle");
318 rb_link_node(node: &candidate->local_node, parent, rb_link: pp);
319 rb_insert_color(&candidate->local_node, &local->client_bundles);
320 call->bundle = rxrpc_get_bundle(bundle: candidate, why: rxrpc_bundle_get_client_call);
321 spin_unlock(lock: &local->client_bundles_lock);
322 _leave(" = B=%u [new]", call->bundle->debug_id);
323 return 0;
324
325found_bundle_free:
326 rxrpc_free_bundle(bundle: candidate);
327found_bundle:
328 call->bundle = rxrpc_get_bundle(bundle, why: rxrpc_bundle_get_client_call);
329 rxrpc_activate_bundle(bundle);
330 spin_unlock(lock: &local->client_bundles_lock);
331 _leave(" = B=%u [found]", call->bundle->debug_id);
332 return 0;
333}
334
335/*
336 * Allocate a new connection and add it into a bundle.
337 */
338static bool rxrpc_add_conn_to_bundle(struct rxrpc_bundle *bundle,
339 unsigned int slot)
340{
341 struct rxrpc_connection *conn, *old;
342 unsigned int shift = slot * RXRPC_MAXCALLS;
343 unsigned int i;
344
345 old = bundle->conns[slot];
346 if (old) {
347 bundle->conns[slot] = NULL;
348 bundle->conn_ids[slot] = 0;
349 trace_rxrpc_client(conn: old, channel: -1, op: rxrpc_client_replace);
350 rxrpc_put_connection(old, rxrpc_conn_put_noreuse);
351 }
352
353 conn = rxrpc_alloc_client_connection(bundle);
354 if (IS_ERR(ptr: conn)) {
355 bundle->alloc_error = PTR_ERR(ptr: conn);
356 return false;
357 }
358
359 rxrpc_activate_bundle(bundle);
360 conn->bundle_shift = shift;
361 bundle->conns[slot] = conn;
362 bundle->conn_ids[slot] = conn->debug_id;
363 for (i = 0; i < RXRPC_MAXCALLS; i++)
364 set_bit(nr: shift + i, addr: &bundle->avail_chans);
365 return true;
366}
367
368/*
369 * Add a connection to a bundle if there are no usable connections or we have
370 * connections waiting for extra capacity.
371 */
372static bool rxrpc_bundle_has_space(struct rxrpc_bundle *bundle)
373{
374 int slot = -1, i, usable;
375
376 _enter("");
377
378 bundle->alloc_error = 0;
379
380 /* See if there are any usable connections. */
381 usable = 0;
382 for (i = 0; i < ARRAY_SIZE(bundle->conns); i++) {
383 if (rxrpc_may_reuse_conn(conn: bundle->conns[i]))
384 usable++;
385 else if (slot == -1)
386 slot = i;
387 }
388
389 if (!usable && bundle->upgrade)
390 bundle->try_upgrade = true;
391
392 if (!usable)
393 goto alloc_conn;
394
395 if (!bundle->avail_chans &&
396 !bundle->try_upgrade &&
397 usable < ARRAY_SIZE(bundle->conns))
398 goto alloc_conn;
399
400 _leave("");
401 return usable;
402
403alloc_conn:
404 return slot >= 0 ? rxrpc_add_conn_to_bundle(bundle, slot) : false;
405}
406
407/*
408 * Assign a channel to the call at the front of the queue and wake the call up.
409 * We don't increment the callNumber counter until this number has been exposed
410 * to the world.
411 */
412static void rxrpc_activate_one_channel(struct rxrpc_connection *conn,
413 unsigned int channel)
414{
415 struct rxrpc_channel *chan = &conn->channels[channel];
416 struct rxrpc_bundle *bundle = conn->bundle;
417 struct rxrpc_call *call = list_entry(bundle->waiting_calls.next,
418 struct rxrpc_call, wait_link);
419 u32 call_id = chan->call_counter + 1;
420
421 _enter("C=%x,%u", conn->debug_id, channel);
422
423 list_del_init(entry: &call->wait_link);
424
425 trace_rxrpc_client(conn, channel, op: rxrpc_client_chan_activate);
426
427 /* Cancel the final ACK on the previous call if it hasn't been sent yet
428 * as the DATA packet will implicitly ACK it.
429 */
430 clear_bit(nr: RXRPC_CONN_FINAL_ACK_0 + channel, addr: &conn->flags);
431 clear_bit(nr: conn->bundle_shift + channel, addr: &bundle->avail_chans);
432
433 rxrpc_see_call(call, rxrpc_call_see_activate_client);
434 call->conn = rxrpc_get_connection(conn, rxrpc_conn_get_activate_call);
435 call->cid = conn->proto.cid | channel;
436 call->call_id = call_id;
437 call->dest_srx.srx_service = conn->service_id;
438 call->cong_ssthresh = call->peer->cong_ssthresh;
439 if (call->cong_cwnd >= call->cong_ssthresh)
440 call->cong_ca_state = RXRPC_CA_CONGEST_AVOIDANCE;
441 else
442 call->cong_ca_state = RXRPC_CA_SLOW_START;
443
444 chan->call_id = call_id;
445 chan->call_debug_id = call->debug_id;
446 chan->call = call;
447
448 rxrpc_see_call(call, rxrpc_call_see_connected);
449 trace_rxrpc_connect_call(call);
450 call->tx_last_sent = ktime_get_real();
451 rxrpc_start_call_timer(call);
452 rxrpc_set_call_state(call, state: RXRPC_CALL_CLIENT_SEND_REQUEST);
453 wake_up(&call->waitq);
454}
455
456/*
457 * Remove a connection from the idle list if it's on it.
458 */
459static void rxrpc_unidle_conn(struct rxrpc_connection *conn)
460{
461 if (!list_empty(head: &conn->cache_link)) {
462 list_del_init(entry: &conn->cache_link);
463 rxrpc_put_connection(conn, rxrpc_conn_put_unidle);
464 }
465}
466
467/*
468 * Assign channels and callNumbers to waiting calls.
469 */
470static void rxrpc_activate_channels(struct rxrpc_bundle *bundle)
471{
472 struct rxrpc_connection *conn;
473 unsigned long avail, mask;
474 unsigned int channel, slot;
475
476 trace_rxrpc_client(NULL, channel: -1, op: rxrpc_client_activate_chans);
477
478 if (bundle->try_upgrade)
479 mask = 1;
480 else
481 mask = ULONG_MAX;
482
483 while (!list_empty(head: &bundle->waiting_calls)) {
484 avail = bundle->avail_chans & mask;
485 if (!avail)
486 break;
487 channel = __ffs(avail);
488 clear_bit(nr: channel, addr: &bundle->avail_chans);
489
490 slot = channel / RXRPC_MAXCALLS;
491 conn = bundle->conns[slot];
492 if (!conn)
493 break;
494
495 if (bundle->try_upgrade)
496 set_bit(nr: RXRPC_CONN_PROBING_FOR_UPGRADE, addr: &conn->flags);
497 rxrpc_unidle_conn(conn);
498
499 channel &= (RXRPC_MAXCALLS - 1);
500 conn->act_chans |= 1 << channel;
501 rxrpc_activate_one_channel(conn, channel);
502 }
503}
504
505/*
506 * Connect waiting channels (called from the I/O thread).
507 */
508void rxrpc_connect_client_calls(struct rxrpc_local *local)
509{
510 struct rxrpc_call *call;
511 LIST_HEAD(new_client_calls);
512
513 spin_lock_irq(lock: &local->client_call_lock);
514 list_splice_tail_init(list: &local->new_client_calls, head: &new_client_calls);
515 spin_unlock_irq(lock: &local->client_call_lock);
516
517 while ((call = list_first_entry_or_null(&new_client_calls,
518 struct rxrpc_call, wait_link))) {
519 struct rxrpc_bundle *bundle = call->bundle;
520
521 list_move_tail(list: &call->wait_link, head: &bundle->waiting_calls);
522 rxrpc_see_call(call, rxrpc_call_see_waiting_call);
523
524 if (rxrpc_bundle_has_space(bundle))
525 rxrpc_activate_channels(bundle);
526 }
527}
528
529/*
530 * Note that a call, and thus a connection, is about to be exposed to the
531 * world.
532 */
533void rxrpc_expose_client_call(struct rxrpc_call *call)
534{
535 unsigned int channel = call->cid & RXRPC_CHANNELMASK;
536 struct rxrpc_connection *conn = call->conn;
537 struct rxrpc_channel *chan = &conn->channels[channel];
538
539 if (!test_and_set_bit(nr: RXRPC_CALL_EXPOSED, addr: &call->flags)) {
540 /* Mark the call ID as being used. If the callNumber counter
541 * exceeds ~2 billion, we kill the connection after its
542 * outstanding calls have finished so that the counter doesn't
543 * wrap.
544 */
545 chan->call_counter++;
546 if (chan->call_counter >= INT_MAX)
547 set_bit(nr: RXRPC_CONN_DONT_REUSE, addr: &conn->flags);
548 trace_rxrpc_client(conn, channel, op: rxrpc_client_exposed);
549
550 spin_lock_irq(lock: &call->peer->lock);
551 hlist_add_head(n: &call->error_link, h: &call->peer->error_targets);
552 spin_unlock_irq(lock: &call->peer->lock);
553 }
554}
555
556/*
557 * Set the reap timer.
558 */
559static void rxrpc_set_client_reap_timer(struct rxrpc_local *local)
560{
561 if (!local->kill_all_client_conns) {
562 unsigned long now = jiffies;
563 unsigned long reap_at = now + rxrpc_conn_idle_client_expiry;
564
565 if (local->rxnet->live)
566 timer_reduce(timer: &local->client_conn_reap_timer, expires: reap_at);
567 }
568}
569
570/*
571 * Disconnect a client call.
572 */
573void rxrpc_disconnect_client_call(struct rxrpc_bundle *bundle, struct rxrpc_call *call)
574{
575 struct rxrpc_connection *conn;
576 struct rxrpc_channel *chan = NULL;
577 struct rxrpc_local *local = bundle->local;
578 unsigned int channel;
579 bool may_reuse;
580 u32 cid;
581
582 _enter("c=%x", call->debug_id);
583
584 /* Calls that have never actually been assigned a channel can simply be
585 * discarded.
586 */
587 conn = call->conn;
588 if (!conn) {
589 _debug("call is waiting");
590 ASSERTCMP(call->call_id, ==, 0);
591 ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags));
592 /* May still be on ->new_client_calls. */
593 spin_lock_irq(lock: &local->client_call_lock);
594 list_del_init(entry: &call->wait_link);
595 spin_unlock_irq(lock: &local->client_call_lock);
596 return;
597 }
598
599 cid = call->cid;
600 channel = cid & RXRPC_CHANNELMASK;
601 chan = &conn->channels[channel];
602 trace_rxrpc_client(conn, channel, op: rxrpc_client_chan_disconnect);
603
604 if (WARN_ON(chan->call != call))
605 return;
606
607 may_reuse = rxrpc_may_reuse_conn(conn);
608
609 /* If a client call was exposed to the world, we save the result for
610 * retransmission.
611 *
612 * We use a barrier here so that the call number and abort code can be
613 * read without needing to take a lock.
614 *
615 * TODO: Make the incoming packet handler check this and handle
616 * terminal retransmission without requiring access to the call.
617 */
618 if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
619 _debug("exposed %u,%u", call->call_id, call->abort_code);
620 __rxrpc_disconnect_call(conn, call);
621
622 if (test_and_clear_bit(nr: RXRPC_CONN_PROBING_FOR_UPGRADE, addr: &conn->flags)) {
623 trace_rxrpc_client(conn, channel, op: rxrpc_client_to_active);
624 bundle->try_upgrade = false;
625 if (may_reuse)
626 rxrpc_activate_channels(bundle);
627 }
628 }
629
630 /* See if we can pass the channel directly to another call. */
631 if (may_reuse && !list_empty(head: &bundle->waiting_calls)) {
632 trace_rxrpc_client(conn, channel, op: rxrpc_client_chan_pass);
633 rxrpc_activate_one_channel(conn, channel);
634 return;
635 }
636
637 /* Schedule the final ACK to be transmitted in a short while so that it
638 * can be skipped if we find a follow-on call. The first DATA packet
639 * of the follow on call will implicitly ACK this call.
640 */
641 if (call->completion == RXRPC_CALL_SUCCEEDED &&
642 test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
643 unsigned long final_ack_at = jiffies + 2;
644
645 chan->final_ack_at = final_ack_at;
646 smp_wmb(); /* vs rxrpc_process_delayed_final_acks() */
647 set_bit(nr: RXRPC_CONN_FINAL_ACK_0 + channel, addr: &conn->flags);
648 rxrpc_reduce_conn_timer(conn, expire_at: final_ack_at);
649 }
650
651 /* Deactivate the channel. */
652 chan->call = NULL;
653 set_bit(nr: conn->bundle_shift + channel, addr: &conn->bundle->avail_chans);
654 conn->act_chans &= ~(1 << channel);
655
656 /* If no channels remain active, then put the connection on the idle
657 * list for a short while. Give it a ref to stop it going away if it
658 * becomes unbundled.
659 */
660 if (!conn->act_chans) {
661 trace_rxrpc_client(conn, channel, op: rxrpc_client_to_idle);
662 conn->idle_timestamp = jiffies;
663
664 rxrpc_get_connection(conn, rxrpc_conn_get_idle);
665 list_move_tail(list: &conn->cache_link, head: &local->idle_client_conns);
666
667 rxrpc_set_client_reap_timer(local);
668 }
669}
670
671/*
672 * Remove a connection from a bundle.
673 */
674static void rxrpc_unbundle_conn(struct rxrpc_connection *conn)
675{
676 struct rxrpc_bundle *bundle = conn->bundle;
677 unsigned int bindex;
678 int i;
679
680 _enter("C=%x", conn->debug_id);
681
682 if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
683 rxrpc_process_delayed_final_acks(conn, true);
684
685 bindex = conn->bundle_shift / RXRPC_MAXCALLS;
686 if (bundle->conns[bindex] == conn) {
687 _debug("clear slot %u", bindex);
688 bundle->conns[bindex] = NULL;
689 bundle->conn_ids[bindex] = 0;
690 for (i = 0; i < RXRPC_MAXCALLS; i++)
691 clear_bit(nr: conn->bundle_shift + i, addr: &bundle->avail_chans);
692 rxrpc_put_client_connection_id(local: bundle->local, conn);
693 rxrpc_deactivate_bundle(bundle);
694 rxrpc_put_connection(conn, rxrpc_conn_put_unbundle);
695 }
696}
697
698/*
699 * Drop the active count on a bundle.
700 */
701void rxrpc_deactivate_bundle(struct rxrpc_bundle *bundle)
702{
703 struct rxrpc_local *local;
704 bool need_put = false;
705
706 if (!bundle)
707 return;
708
709 local = bundle->local;
710 if (atomic_dec_and_lock(&bundle->active, &local->client_bundles_lock)) {
711 if (!bundle->exclusive) {
712 _debug("erase bundle");
713 rb_erase(&bundle->local_node, &local->client_bundles);
714 need_put = true;
715 }
716
717 spin_unlock(lock: &local->client_bundles_lock);
718 if (need_put)
719 rxrpc_put_bundle(bundle, why: rxrpc_bundle_put_discard);
720 }
721}
722
723/*
724 * Clean up a dead client connection.
725 */
726void rxrpc_kill_client_conn(struct rxrpc_connection *conn)
727{
728 struct rxrpc_local *local = conn->local;
729 struct rxrpc_net *rxnet = local->rxnet;
730
731 _enter("C=%x", conn->debug_id);
732
733 trace_rxrpc_client(conn, channel: -1, op: rxrpc_client_cleanup);
734 atomic_dec(v: &rxnet->nr_client_conns);
735
736 rxrpc_put_client_connection_id(local, conn);
737}
738
739/*
740 * Discard expired client connections from the idle list. Each conn in the
741 * idle list has been exposed and holds an extra ref because of that.
742 *
743 * This may be called from conn setup or from a work item so cannot be
744 * considered non-reentrant.
745 */
746void rxrpc_discard_expired_client_conns(struct rxrpc_local *local)
747{
748 struct rxrpc_connection *conn;
749 unsigned long expiry, conn_expires_at, now;
750 unsigned int nr_conns;
751
752 _enter("");
753
754 /* We keep an estimate of what the number of conns ought to be after
755 * we've discarded some so that we don't overdo the discarding.
756 */
757 nr_conns = atomic_read(v: &local->rxnet->nr_client_conns);
758
759next:
760 conn = list_first_entry_or_null(&local->idle_client_conns,
761 struct rxrpc_connection, cache_link);
762 if (!conn)
763 return;
764
765 if (!local->kill_all_client_conns) {
766 /* If the number of connections is over the reap limit, we
767 * expedite discard by reducing the expiry timeout. We must,
768 * however, have at least a short grace period to be able to do
769 * final-ACK or ABORT retransmission.
770 */
771 expiry = rxrpc_conn_idle_client_expiry;
772 if (nr_conns > rxrpc_reap_client_connections)
773 expiry = rxrpc_conn_idle_client_fast_expiry;
774 if (conn->local->service_closed)
775 expiry = rxrpc_closed_conn_expiry * HZ;
776
777 conn_expires_at = conn->idle_timestamp + expiry;
778
779 now = jiffies;
780 if (time_after(conn_expires_at, now))
781 goto not_yet_expired;
782 }
783
784 atomic_dec(v: &conn->active);
785 trace_rxrpc_client(conn, channel: -1, op: rxrpc_client_discard);
786 list_del_init(entry: &conn->cache_link);
787
788 rxrpc_unbundle_conn(conn);
789 /* Drop the ->cache_link ref */
790 rxrpc_put_connection(conn, rxrpc_conn_put_discard_idle);
791
792 nr_conns--;
793 goto next;
794
795not_yet_expired:
796 /* The connection at the front of the queue hasn't yet expired, so
797 * schedule the work item for that point if we discarded something.
798 *
799 * We don't worry if the work item is already scheduled - it can look
800 * after rescheduling itself at a later time. We could cancel it, but
801 * then things get messier.
802 */
803 _debug("not yet");
804 if (!local->kill_all_client_conns)
805 timer_reduce(timer: &local->client_conn_reap_timer, expires: conn_expires_at);
806
807 _leave("");
808}
809
810/*
811 * Clean up the client connections on a local endpoint.
812 */
813void rxrpc_clean_up_local_conns(struct rxrpc_local *local)
814{
815 struct rxrpc_connection *conn;
816
817 _enter("");
818
819 local->kill_all_client_conns = true;
820
821 timer_delete_sync(timer: &local->client_conn_reap_timer);
822
823 while ((conn = list_first_entry_or_null(&local->idle_client_conns,
824 struct rxrpc_connection, cache_link))) {
825 list_del_init(entry: &conn->cache_link);
826 atomic_dec(v: &conn->active);
827 trace_rxrpc_client(conn, channel: -1, op: rxrpc_client_discard);
828 rxrpc_unbundle_conn(conn);
829 rxrpc_put_connection(conn, rxrpc_conn_put_local_dead);
830 }
831
832 _leave(" [culled]");
833}
834

source code of linux/net/rxrpc/conn_client.c