1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Client connection-specific management code.
4 * Copyright (C) 2016, 2020 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
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.
11 * There are flags of relevance to the cache:
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.
17 * The caching state may only be changed if the cache lock is held.
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.
24 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
26 #include <linux/slab.h>
27 #include <linux/idr.h>
28 #include <linux/timer.h>
29 #include <linux/sched/signal.h>
31 #include "ar-internal.h"
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;
38 * We use machine-unique IDs for our client connections.
40 DEFINE_IDR(rxrpc_client_conn_ids);
41 static DEFINE_SPINLOCK(rxrpc_conn_id_lock);
44 * Get a connection ID and epoch for a client connection from the global pool.
45 * The connection struct pointer is then recorded in the idr radix tree. The
46 * epoch doesn't change until the client is rebooted (or, at least, unless the
47 * module is unloaded).
49 static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn,
52 struct rxrpc_net *rxnet = conn->params.local->rxnet;
58 spin_lock(&rxrpc_conn_id_lock);
60 id = idr_alloc_cyclic(&rxrpc_client_conn_ids, conn,
61 1, 0x40000000, GFP_NOWAIT);
65 spin_unlock(&rxrpc_conn_id_lock);
68 conn->proto.epoch = rxnet->epoch;
69 conn->proto.cid = id << RXRPC_CIDSHIFT;
70 set_bit(RXRPC_CONN_HAS_IDR, &conn->flags);
71 _leave(" [CID %x]", conn->proto.cid);
75 spin_unlock(&rxrpc_conn_id_lock);
82 * Release a connection ID for a client connection from the global pool.
84 static void rxrpc_put_client_connection_id(struct rxrpc_connection *conn)
86 if (test_bit(RXRPC_CONN_HAS_IDR, &conn->flags)) {
87 spin_lock(&rxrpc_conn_id_lock);
88 idr_remove(&rxrpc_client_conn_ids,
89 conn->proto.cid >> RXRPC_CIDSHIFT);
90 spin_unlock(&rxrpc_conn_id_lock);
95 * Destroy the client connection ID tree.
97 void rxrpc_destroy_client_conn_ids(void)
99 struct rxrpc_connection *conn;
102 if (!idr_is_empty(&rxrpc_client_conn_ids)) {
103 idr_for_each_entry(&rxrpc_client_conn_ids, conn, id) {
104 pr_err("AF_RXRPC: Leaked client conn %p {%d}\n",
105 conn, atomic_read(&conn->usage));
110 idr_destroy(&rxrpc_client_conn_ids);
114 * Allocate a connection bundle.
116 static struct rxrpc_bundle *rxrpc_alloc_bundle(struct rxrpc_conn_parameters *cp,
119 struct rxrpc_bundle *bundle;
121 bundle = kzalloc(sizeof(*bundle), gfp);
123 bundle->params = *cp;
124 rxrpc_get_peer(bundle->params.peer);
125 atomic_set(&bundle->usage, 1);
126 spin_lock_init(&bundle->channel_lock);
127 INIT_LIST_HEAD(&bundle->waiting_calls);
132 struct rxrpc_bundle *rxrpc_get_bundle(struct rxrpc_bundle *bundle)
134 atomic_inc(&bundle->usage);
138 void rxrpc_put_bundle(struct rxrpc_bundle *bundle)
140 unsigned int d = bundle->debug_id;
141 unsigned int u = atomic_dec_return(&bundle->usage);
143 _debug("PUT B=%x %u", d, u);
145 rxrpc_put_peer(bundle->params.peer);
151 * Allocate a client connection.
153 static struct rxrpc_connection *
154 rxrpc_alloc_client_connection(struct rxrpc_bundle *bundle, gfp_t gfp)
156 struct rxrpc_connection *conn;
157 struct rxrpc_net *rxnet = bundle->params.local->rxnet;
162 conn = rxrpc_alloc_connection(gfp);
164 _leave(" = -ENOMEM");
165 return ERR_PTR(-ENOMEM);
168 atomic_set(&conn->usage, 1);
169 conn->bundle = bundle;
170 conn->params = bundle->params;
171 conn->out_clientflag = RXRPC_CLIENT_INITIATED;
172 conn->state = RXRPC_CONN_CLIENT;
173 conn->service_id = conn->params.service_id;
175 ret = rxrpc_get_client_connection_id(conn, gfp);
179 ret = rxrpc_init_client_conn_security(conn);
183 ret = conn->security->prime_packet_security(conn);
187 atomic_inc(&rxnet->nr_conns);
188 write_lock(&rxnet->conn_lock);
189 list_add_tail(&conn->proc_link, &rxnet->conn_proc_list);
190 write_unlock(&rxnet->conn_lock);
192 rxrpc_get_bundle(bundle);
193 rxrpc_get_peer(conn->params.peer);
194 rxrpc_get_local(conn->params.local);
195 key_get(conn->params.key);
197 trace_rxrpc_conn(conn->debug_id, rxrpc_conn_new_client,
198 atomic_read(&conn->usage),
199 __builtin_return_address(0));
201 atomic_inc(&rxnet->nr_client_conns);
202 trace_rxrpc_client(conn, -1, rxrpc_client_alloc);
203 _leave(" = %p", conn);
207 conn->security->clear(conn);
209 rxrpc_put_client_connection_id(conn);
212 _leave(" = %d", ret);
217 * Determine if a connection may be reused.
219 static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn)
221 struct rxrpc_net *rxnet;
222 int id_cursor, id, distance, limit;
227 rxnet = conn->params.local->rxnet;
228 if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags))
231 if (conn->state != RXRPC_CONN_CLIENT ||
232 conn->proto.epoch != rxnet->epoch)
233 goto mark_dont_reuse;
235 /* The IDR tree gets very expensive on memory if the connection IDs are
236 * widely scattered throughout the number space, so we shall want to
237 * kill off connections that, say, have an ID more than about four
238 * times the maximum number of client conns away from the current
239 * allocation point to try and keep the IDs concentrated.
241 id_cursor = idr_get_cursor(&rxrpc_client_conn_ids);
242 id = conn->proto.cid >> RXRPC_CIDSHIFT;
243 distance = id - id_cursor;
245 distance = -distance;
246 limit = max_t(unsigned long, atomic_read(&rxnet->nr_conns) * 4, 1024);
247 if (distance > limit)
248 goto mark_dont_reuse;
253 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
259 * Look up the conn bundle that matches the connection parameters, adding it if
260 * it doesn't yet exist.
262 static struct rxrpc_bundle *rxrpc_look_up_bundle(struct rxrpc_conn_parameters *cp,
265 static atomic_t rxrpc_bundle_id;
266 struct rxrpc_bundle *bundle, *candidate;
267 struct rxrpc_local *local = cp->local;
268 struct rb_node *p, **pp, *parent;
271 _enter("{%px,%x,%u,%u}",
272 cp->peer, key_serial(cp->key), cp->security_level, cp->upgrade);
275 return rxrpc_alloc_bundle(cp, gfp);
277 /* First, see if the bundle is already there. */
279 spin_lock(&local->client_bundles_lock);
280 p = local->client_bundles.rb_node;
282 bundle = rb_entry(p, struct rxrpc_bundle, local_node);
284 #define cmp(X) ((long)bundle->params.X - (long)cp->X)
287 cmp(security_level) ?:
297 spin_unlock(&local->client_bundles_lock);
300 /* It wasn't. We need to add one. */
301 candidate = rxrpc_alloc_bundle(cp, gfp);
306 spin_lock(&local->client_bundles_lock);
307 pp = &local->client_bundles.rb_node;
311 bundle = rb_entry(parent, struct rxrpc_bundle, local_node);
313 #define cmp(X) ((long)bundle->params.X - (long)cp->X)
316 cmp(security_level) ?:
320 pp = &(*pp)->rb_left;
322 pp = &(*pp)->rb_right;
324 goto found_bundle_free;
327 _debug("new bundle");
328 candidate->debug_id = atomic_inc_return(&rxrpc_bundle_id);
329 rb_link_node(&candidate->local_node, parent, pp);
330 rb_insert_color(&candidate->local_node, &local->client_bundles);
331 rxrpc_get_bundle(candidate);
332 spin_unlock(&local->client_bundles_lock);
333 _leave(" = %u [new]", candidate->debug_id);
339 rxrpc_get_bundle(bundle);
340 spin_unlock(&local->client_bundles_lock);
341 _leave(" = %u [found]", bundle->debug_id);
346 * Create or find a client bundle to use for a call.
348 * If we return with a connection, the call will be on its waiting list. It's
349 * left to the caller to assign a channel and wake up the call.
351 static struct rxrpc_bundle *rxrpc_prep_call(struct rxrpc_sock *rx,
352 struct rxrpc_call *call,
353 struct rxrpc_conn_parameters *cp,
354 struct sockaddr_rxrpc *srx,
357 struct rxrpc_bundle *bundle;
359 _enter("{%d,%lx},", call->debug_id, call->user_call_ID);
361 cp->peer = rxrpc_lookup_peer(rx, cp->local, srx, gfp);
365 call->cong_cwnd = cp->peer->cong_cwnd;
366 if (call->cong_cwnd >= call->cong_ssthresh)
367 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
369 call->cong_mode = RXRPC_CALL_SLOW_START;
371 __set_bit(RXRPC_CALL_UPGRADE, &call->flags);
373 /* Find the client connection bundle. */
374 bundle = rxrpc_look_up_bundle(cp, gfp);
378 /* Get this call queued. Someone else may activate it whilst we're
379 * lining up a new connection, but that's fine.
381 spin_lock(&bundle->channel_lock);
382 list_add_tail(&call->chan_wait_link, &bundle->waiting_calls);
383 spin_unlock(&bundle->channel_lock);
385 _leave(" = [B=%x]", bundle->debug_id);
389 _leave(" = -ENOMEM");
390 return ERR_PTR(-ENOMEM);
394 * Allocate a new connection and add it into a bundle.
396 static void rxrpc_add_conn_to_bundle(struct rxrpc_bundle *bundle, gfp_t gfp)
397 __releases(bundle->channel_lock)
399 struct rxrpc_connection *candidate = NULL, *old = NULL;
405 conflict = bundle->alloc_conn;
407 bundle->alloc_conn = true;
408 spin_unlock(&bundle->channel_lock);
414 candidate = rxrpc_alloc_client_connection(bundle, gfp);
416 spin_lock(&bundle->channel_lock);
417 bundle->alloc_conn = false;
419 if (IS_ERR(candidate)) {
420 bundle->alloc_error = PTR_ERR(candidate);
421 spin_unlock(&bundle->channel_lock);
422 _leave(" [err %ld]", PTR_ERR(candidate));
426 bundle->alloc_error = 0;
428 for (i = 0; i < ARRAY_SIZE(bundle->conns); i++) {
429 unsigned int shift = i * RXRPC_MAXCALLS;
432 old = bundle->conns[i];
433 if (!rxrpc_may_reuse_conn(old)) {
435 trace_rxrpc_client(old, -1, rxrpc_client_replace);
436 candidate->bundle_shift = shift;
437 bundle->conns[i] = candidate;
438 for (j = 0; j < RXRPC_MAXCALLS; j++)
439 set_bit(shift + j, &bundle->avail_chans);
447 spin_unlock(&bundle->channel_lock);
450 _debug("discard C=%x", candidate->debug_id);
451 trace_rxrpc_client(candidate, -1, rxrpc_client_duplicate);
452 rxrpc_put_connection(candidate);
455 rxrpc_put_connection(old);
460 * Add a connection to a bundle if there are no usable connections or we have
461 * connections waiting for extra capacity.
463 static void rxrpc_maybe_add_conn(struct rxrpc_bundle *bundle, gfp_t gfp)
465 struct rxrpc_call *call;
470 spin_lock(&bundle->channel_lock);
472 /* See if there are any usable connections. */
474 for (i = 0; i < ARRAY_SIZE(bundle->conns); i++)
475 if (rxrpc_may_reuse_conn(bundle->conns[i]))
478 if (!usable && !list_empty(&bundle->waiting_calls)) {
479 call = list_first_entry(&bundle->waiting_calls,
480 struct rxrpc_call, chan_wait_link);
481 if (test_bit(RXRPC_CALL_UPGRADE, &call->flags))
482 bundle->try_upgrade = true;
488 if (!bundle->avail_chans &&
489 !bundle->try_upgrade &&
490 !list_empty(&bundle->waiting_calls) &&
491 usable < ARRAY_SIZE(bundle->conns))
494 spin_unlock(&bundle->channel_lock);
499 return rxrpc_add_conn_to_bundle(bundle, gfp);
503 * Assign a channel to the call at the front of the queue and wake the call up.
504 * We don't increment the callNumber counter until this number has been exposed
507 static void rxrpc_activate_one_channel(struct rxrpc_connection *conn,
508 unsigned int channel)
510 struct rxrpc_channel *chan = &conn->channels[channel];
511 struct rxrpc_bundle *bundle = conn->bundle;
512 struct rxrpc_call *call = list_entry(bundle->waiting_calls.next,
513 struct rxrpc_call, chan_wait_link);
514 u32 call_id = chan->call_counter + 1;
516 _enter("C=%x,%u", conn->debug_id, channel);
518 trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate);
520 /* Cancel the final ACK on the previous call if it hasn't been sent yet
521 * as the DATA packet will implicitly ACK it.
523 clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
524 clear_bit(conn->bundle_shift + channel, &bundle->avail_chans);
526 rxrpc_see_call(call);
527 list_del_init(&call->chan_wait_link);
528 call->peer = rxrpc_get_peer(conn->params.peer);
529 call->conn = rxrpc_get_connection(conn);
530 call->cid = conn->proto.cid | channel;
531 call->call_id = call_id;
532 call->security = conn->security;
533 call->security_ix = conn->security_ix;
534 call->service_id = conn->service_id;
536 trace_rxrpc_connect_call(call);
537 _net("CONNECT call %08x:%08x as call %d on conn %d",
538 call->cid, call->call_id, call->debug_id, conn->debug_id);
540 write_lock_bh(&call->state_lock);
541 call->state = RXRPC_CALL_CLIENT_SEND_REQUEST;
542 write_unlock_bh(&call->state_lock);
544 /* Paired with the read barrier in rxrpc_connect_call(). This orders
545 * cid and epoch in the connection wrt to call_id without the need to
546 * take the channel_lock.
548 * We provisionally assign a callNumber at this point, but we don't
549 * confirm it until the call is about to be exposed.
551 * TODO: Pair with a barrier in the data_ready handler when that looks
552 * at the call ID through a connection channel.
556 chan->call_id = call_id;
557 chan->call_debug_id = call->debug_id;
558 rcu_assign_pointer(chan->call, call);
559 wake_up(&call->waitq);
563 * Remove a connection from the idle list if it's on it.
565 static void rxrpc_unidle_conn(struct rxrpc_bundle *bundle, struct rxrpc_connection *conn)
567 struct rxrpc_net *rxnet = bundle->params.local->rxnet;
570 if (!list_empty(&conn->cache_link)) {
572 spin_lock(&rxnet->client_conn_cache_lock);
573 if (!list_empty(&conn->cache_link)) {
574 list_del_init(&conn->cache_link);
577 spin_unlock(&rxnet->client_conn_cache_lock);
579 rxrpc_put_connection(conn);
584 * Assign channels and callNumbers to waiting calls with channel_lock
587 static void rxrpc_activate_channels_locked(struct rxrpc_bundle *bundle)
589 struct rxrpc_connection *conn;
590 unsigned long avail, mask;
591 unsigned int channel, slot;
593 if (bundle->try_upgrade)
598 while (!list_empty(&bundle->waiting_calls)) {
599 avail = bundle->avail_chans & mask;
602 channel = __ffs(avail);
603 clear_bit(channel, &bundle->avail_chans);
605 slot = channel / RXRPC_MAXCALLS;
606 conn = bundle->conns[slot];
610 if (bundle->try_upgrade)
611 set_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags);
612 rxrpc_unidle_conn(bundle, conn);
614 channel &= (RXRPC_MAXCALLS - 1);
615 conn->act_chans |= 1 << channel;
616 rxrpc_activate_one_channel(conn, channel);
621 * Assign channels and callNumbers to waiting calls.
623 static void rxrpc_activate_channels(struct rxrpc_bundle *bundle)
625 _enter("B=%x", bundle->debug_id);
627 trace_rxrpc_client(NULL, -1, rxrpc_client_activate_chans);
629 if (!bundle->avail_chans)
632 spin_lock(&bundle->channel_lock);
633 rxrpc_activate_channels_locked(bundle);
634 spin_unlock(&bundle->channel_lock);
639 * Wait for a callNumber and a channel to be granted to a call.
641 static int rxrpc_wait_for_channel(struct rxrpc_bundle *bundle,
642 struct rxrpc_call *call, gfp_t gfp)
644 DECLARE_WAITQUEUE(myself, current);
647 _enter("%d", call->debug_id);
649 if (!gfpflags_allow_blocking(gfp)) {
650 rxrpc_maybe_add_conn(bundle, gfp);
651 rxrpc_activate_channels(bundle);
652 ret = bundle->alloc_error ?: -EAGAIN;
656 add_wait_queue_exclusive(&call->waitq, &myself);
658 rxrpc_maybe_add_conn(bundle, gfp);
659 rxrpc_activate_channels(bundle);
660 ret = bundle->alloc_error;
664 switch (call->interruptibility) {
665 case RXRPC_INTERRUPTIBLE:
666 case RXRPC_PREINTERRUPTIBLE:
667 set_current_state(TASK_INTERRUPTIBLE);
669 case RXRPC_UNINTERRUPTIBLE:
671 set_current_state(TASK_UNINTERRUPTIBLE);
674 if (READ_ONCE(call->state) != RXRPC_CALL_CLIENT_AWAIT_CONN)
676 if ((call->interruptibility == RXRPC_INTERRUPTIBLE ||
677 call->interruptibility == RXRPC_PREINTERRUPTIBLE) &&
678 signal_pending(current)) {
684 remove_wait_queue(&call->waitq, &myself);
685 __set_current_state(TASK_RUNNING);
688 _leave(" = %d", ret);
693 * find a connection for a call
694 * - called in process context with IRQs enabled
696 int rxrpc_connect_call(struct rxrpc_sock *rx,
697 struct rxrpc_call *call,
698 struct rxrpc_conn_parameters *cp,
699 struct sockaddr_rxrpc *srx,
702 struct rxrpc_bundle *bundle;
703 struct rxrpc_net *rxnet = cp->local->rxnet;
706 _enter("{%d,%lx},", call->debug_id, call->user_call_ID);
708 rxrpc_discard_expired_client_conns(&rxnet->client_conn_reaper);
710 bundle = rxrpc_prep_call(rx, call, cp, srx, gfp);
711 if (IS_ERR(bundle)) {
712 ret = PTR_ERR(bundle);
716 if (call->state == RXRPC_CALL_CLIENT_AWAIT_CONN) {
717 ret = rxrpc_wait_for_channel(bundle, call, gfp);
723 /* Paired with the write barrier in rxrpc_activate_one_channel(). */
727 rxrpc_put_bundle(bundle);
729 _leave(" = %d", ret);
733 spin_lock(&bundle->channel_lock);
734 list_del_init(&call->chan_wait_link);
735 spin_unlock(&bundle->channel_lock);
737 if (call->state != RXRPC_CALL_CLIENT_AWAIT_CONN) {
739 goto granted_channel;
742 trace_rxrpc_client(call->conn, ret, rxrpc_client_chan_wait_failed);
743 rxrpc_set_call_completion(call, RXRPC_CALL_LOCAL_ERROR, 0, ret);
744 rxrpc_disconnect_client_call(bundle, call);
749 * Note that a call, and thus a connection, is about to be exposed to the
752 void rxrpc_expose_client_call(struct rxrpc_call *call)
754 unsigned int channel = call->cid & RXRPC_CHANNELMASK;
755 struct rxrpc_connection *conn = call->conn;
756 struct rxrpc_channel *chan = &conn->channels[channel];
758 if (!test_and_set_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
759 /* Mark the call ID as being used. If the callNumber counter
760 * exceeds ~2 billion, we kill the connection after its
761 * outstanding calls have finished so that the counter doesn't
764 chan->call_counter++;
765 if (chan->call_counter >= INT_MAX)
766 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
767 trace_rxrpc_client(conn, channel, rxrpc_client_exposed);
772 * Set the reap timer.
774 static void rxrpc_set_client_reap_timer(struct rxrpc_net *rxnet)
776 if (!rxnet->kill_all_client_conns) {
777 unsigned long now = jiffies;
778 unsigned long reap_at = now + rxrpc_conn_idle_client_expiry;
781 timer_reduce(&rxnet->client_conn_reap_timer, reap_at);
786 * Disconnect a client call.
788 void rxrpc_disconnect_client_call(struct rxrpc_bundle *bundle, struct rxrpc_call *call)
790 struct rxrpc_connection *conn;
791 struct rxrpc_channel *chan = NULL;
792 struct rxrpc_net *rxnet = bundle->params.local->rxnet;
793 unsigned int channel;
797 _enter("c=%x", call->debug_id);
799 spin_lock(&bundle->channel_lock);
800 set_bit(RXRPC_CALL_DISCONNECTED, &call->flags);
802 /* Calls that have never actually been assigned a channel can simply be
807 _debug("call is waiting");
808 ASSERTCMP(call->call_id, ==, 0);
809 ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags));
810 list_del_init(&call->chan_wait_link);
815 channel = cid & RXRPC_CHANNELMASK;
816 chan = &conn->channels[channel];
817 trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect);
819 if (rcu_access_pointer(chan->call) != call) {
820 spin_unlock(&bundle->channel_lock);
824 may_reuse = rxrpc_may_reuse_conn(conn);
826 /* If a client call was exposed to the world, we save the result for
829 * We use a barrier here so that the call number and abort code can be
830 * read without needing to take a lock.
832 * TODO: Make the incoming packet handler check this and handle
833 * terminal retransmission without requiring access to the call.
835 if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
836 _debug("exposed %u,%u", call->call_id, call->abort_code);
837 __rxrpc_disconnect_call(conn, call);
839 if (test_and_clear_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) {
840 trace_rxrpc_client(conn, channel, rxrpc_client_to_active);
841 bundle->try_upgrade = false;
843 rxrpc_activate_channels_locked(bundle);
848 /* See if we can pass the channel directly to another call. */
849 if (may_reuse && !list_empty(&bundle->waiting_calls)) {
850 trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
851 rxrpc_activate_one_channel(conn, channel);
855 /* Schedule the final ACK to be transmitted in a short while so that it
856 * can be skipped if we find a follow-on call. The first DATA packet
857 * of the follow on call will implicitly ACK this call.
859 if (call->completion == RXRPC_CALL_SUCCEEDED &&
860 test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
861 unsigned long final_ack_at = jiffies + 2;
863 WRITE_ONCE(chan->final_ack_at, final_ack_at);
864 smp_wmb(); /* vs rxrpc_process_delayed_final_acks() */
865 set_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags);
866 rxrpc_reduce_conn_timer(conn, final_ack_at);
869 /* Deactivate the channel. */
870 rcu_assign_pointer(chan->call, NULL);
871 set_bit(conn->bundle_shift + channel, &conn->bundle->avail_chans);
872 conn->act_chans &= ~(1 << channel);
874 /* If no channels remain active, then put the connection on the idle
875 * list for a short while. Give it a ref to stop it going away if it
878 if (!conn->act_chans) {
879 trace_rxrpc_client(conn, channel, rxrpc_client_to_idle);
880 conn->idle_timestamp = jiffies;
882 rxrpc_get_connection(conn);
883 spin_lock(&rxnet->client_conn_cache_lock);
884 list_move_tail(&conn->cache_link, &rxnet->idle_client_conns);
885 spin_unlock(&rxnet->client_conn_cache_lock);
887 rxrpc_set_client_reap_timer(rxnet);
891 spin_unlock(&bundle->channel_lock);
897 * Remove a connection from a bundle.
899 static void rxrpc_unbundle_conn(struct rxrpc_connection *conn)
901 struct rxrpc_bundle *bundle = conn->bundle;
902 struct rxrpc_local *local = bundle->params.local;
904 bool need_drop = false, need_put = false;
907 _enter("C=%x", conn->debug_id);
909 if (conn->flags & RXRPC_CONN_FINAL_ACK_MASK)
910 rxrpc_process_delayed_final_acks(conn, true);
912 spin_lock(&bundle->channel_lock);
913 bindex = conn->bundle_shift / RXRPC_MAXCALLS;
914 if (bundle->conns[bindex] == conn) {
915 _debug("clear slot %u", bindex);
916 bundle->conns[bindex] = NULL;
917 for (i = 0; i < RXRPC_MAXCALLS; i++)
918 clear_bit(conn->bundle_shift + i, &bundle->avail_chans);
921 spin_unlock(&bundle->channel_lock);
923 /* If there are no more connections, remove the bundle */
924 if (!bundle->avail_chans) {
925 _debug("maybe unbundle");
926 spin_lock(&local->client_bundles_lock);
928 for (i = 0; i < ARRAY_SIZE(bundle->conns); i++)
929 if (bundle->conns[i])
931 if (i == ARRAY_SIZE(bundle->conns) && !bundle->params.exclusive) {
932 _debug("erase bundle");
933 rb_erase(&bundle->local_node, &local->client_bundles);
937 spin_unlock(&local->client_bundles_lock);
939 rxrpc_put_bundle(bundle);
943 rxrpc_put_connection(conn);
948 * Clean up a dead client connection.
950 static void rxrpc_kill_client_conn(struct rxrpc_connection *conn)
952 struct rxrpc_local *local = conn->params.local;
953 struct rxrpc_net *rxnet = local->rxnet;
955 _enter("C=%x", conn->debug_id);
957 trace_rxrpc_client(conn, -1, rxrpc_client_cleanup);
958 atomic_dec(&rxnet->nr_client_conns);
960 rxrpc_put_client_connection_id(conn);
961 rxrpc_kill_connection(conn);
965 * Clean up a dead client connections.
967 void rxrpc_put_client_conn(struct rxrpc_connection *conn)
969 const void *here = __builtin_return_address(0);
970 unsigned int debug_id = conn->debug_id;
973 n = atomic_dec_return(&conn->usage);
974 trace_rxrpc_conn(debug_id, rxrpc_conn_put_client, n, here);
977 rxrpc_kill_client_conn(conn);
982 * Discard expired client connections from the idle list. Each conn in the
983 * idle list has been exposed and holds an extra ref because of that.
985 * This may be called from conn setup or from a work item so cannot be
986 * considered non-reentrant.
988 void rxrpc_discard_expired_client_conns(struct work_struct *work)
990 struct rxrpc_connection *conn;
991 struct rxrpc_net *rxnet =
992 container_of(work, struct rxrpc_net, client_conn_reaper);
993 unsigned long expiry, conn_expires_at, now;
994 unsigned int nr_conns;
998 if (list_empty(&rxnet->idle_client_conns)) {
1003 /* Don't double up on the discarding */
1004 if (!spin_trylock(&rxnet->client_conn_discard_lock)) {
1005 _leave(" [already]");
1009 /* We keep an estimate of what the number of conns ought to be after
1010 * we've discarded some so that we don't overdo the discarding.
1012 nr_conns = atomic_read(&rxnet->nr_client_conns);
1015 spin_lock(&rxnet->client_conn_cache_lock);
1017 if (list_empty(&rxnet->idle_client_conns))
1020 conn = list_entry(rxnet->idle_client_conns.next,
1021 struct rxrpc_connection, cache_link);
1023 if (!rxnet->kill_all_client_conns) {
1024 /* If the number of connections is over the reap limit, we
1025 * expedite discard by reducing the expiry timeout. We must,
1026 * however, have at least a short grace period to be able to do
1027 * final-ACK or ABORT retransmission.
1029 expiry = rxrpc_conn_idle_client_expiry;
1030 if (nr_conns > rxrpc_reap_client_connections)
1031 expiry = rxrpc_conn_idle_client_fast_expiry;
1032 if (conn->params.local->service_closed)
1033 expiry = rxrpc_closed_conn_expiry * HZ;
1035 conn_expires_at = conn->idle_timestamp + expiry;
1037 now = READ_ONCE(jiffies);
1038 if (time_after(conn_expires_at, now))
1039 goto not_yet_expired;
1042 trace_rxrpc_client(conn, -1, rxrpc_client_discard);
1043 list_del_init(&conn->cache_link);
1045 spin_unlock(&rxnet->client_conn_cache_lock);
1047 rxrpc_unbundle_conn(conn);
1048 rxrpc_put_connection(conn); /* Drop the ->cache_link ref */
1054 /* The connection at the front of the queue hasn't yet expired, so
1055 * schedule the work item for that point if we discarded something.
1057 * We don't worry if the work item is already scheduled - it can look
1058 * after rescheduling itself at a later time. We could cancel it, but
1059 * then things get messier.
1062 if (!rxnet->kill_all_client_conns)
1063 timer_reduce(&rxnet->client_conn_reap_timer, conn_expires_at);
1066 spin_unlock(&rxnet->client_conn_cache_lock);
1067 spin_unlock(&rxnet->client_conn_discard_lock);
1072 * Preemptively destroy all the client connection records rather than waiting
1073 * for them to time out
1075 void rxrpc_destroy_all_client_connections(struct rxrpc_net *rxnet)
1079 spin_lock(&rxnet->client_conn_cache_lock);
1080 rxnet->kill_all_client_conns = true;
1081 spin_unlock(&rxnet->client_conn_cache_lock);
1083 del_timer_sync(&rxnet->client_conn_reap_timer);
1085 if (!rxrpc_queue_work(&rxnet->client_conn_reaper))
1086 _debug("destroy: queue failed");
1092 * Clean up the client connections on a local endpoint.
1094 void rxrpc_clean_up_local_conns(struct rxrpc_local *local)
1096 struct rxrpc_connection *conn, *tmp;
1097 struct rxrpc_net *rxnet = local->rxnet;
1098 LIST_HEAD(graveyard);
1102 spin_lock(&rxnet->client_conn_cache_lock);
1104 list_for_each_entry_safe(conn, tmp, &rxnet->idle_client_conns,
1106 if (conn->params.local == local) {
1107 trace_rxrpc_client(conn, -1, rxrpc_client_discard);
1108 list_move(&conn->cache_link, &graveyard);
1112 spin_unlock(&rxnet->client_conn_cache_lock);
1114 while (!list_empty(&graveyard)) {
1115 conn = list_entry(graveyard.next,
1116 struct rxrpc_connection, cache_link);
1117 list_del_init(&conn->cache_link);
1118 rxrpc_unbundle_conn(conn);
1119 rxrpc_put_connection(conn);
1122 _leave(" [culled]");