1 /* Client connection-specific management code.
3 * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
12 * Client connections need to be cached for a little while after they've made a
13 * call so as to handle retransmitted DATA packets in case the server didn't
14 * receive the final ACK or terminating ABORT we sent it.
16 * Client connections can be in one of a number of cache states:
18 * (1) INACTIVE - The connection is not held in any list and may not have been
19 * exposed to the world. If it has been previously exposed, it was
20 * discarded from the idle list after expiring.
22 * (2) WAITING - The connection is waiting for the number of client conns to
23 * drop below the maximum capacity. Calls may be in progress upon it from
24 * when it was active and got culled.
26 * The connection is on the rxrpc_waiting_client_conns list which is kept
27 * in to-be-granted order. Culled conns with waiters go to the back of
28 * the queue just like new conns.
30 * (3) ACTIVE - The connection has at least one call in progress upon it, it
31 * may freely grant available channels to new calls and calls may be
32 * waiting on it for channels to become available.
34 * The connection is on the rxnet->active_client_conns list which is kept
35 * in activation order for culling purposes.
37 * rxrpc_nr_active_client_conns is held incremented also.
39 * (4) UPGRADE - As for ACTIVE, but only one call may be in progress and is
40 * being used to probe for service upgrade.
42 * (5) CULLED - The connection got summarily culled to try and free up
43 * capacity. Calls currently in progress on the connection are allowed to
44 * continue, but new calls will have to wait. There can be no waiters in
45 * this state - the conn would have to go to the WAITING state instead.
47 * (6) IDLE - The connection has no calls in progress upon it and must have
48 * been exposed to the world (ie. the EXPOSED flag must be set). When it
49 * expires, the EXPOSED flag is cleared and the connection transitions to
52 * The connection is on the rxnet->idle_client_conns list which is kept in
53 * order of how soon they'll expire.
55 * There are flags of relevance to the cache:
57 * (1) EXPOSED - The connection ID got exposed to the world. If this flag is
58 * set, an extra ref is added to the connection preventing it from being
59 * reaped when it has no calls outstanding. This flag is cleared and the
60 * ref dropped when a conn is discarded from the idle list.
62 * This allows us to move terminal call state retransmission to the
63 * connection and to discard the call immediately we think it is done
64 * with. It also give us a chance to reuse the connection.
66 * (2) DONT_REUSE - The connection should be discarded as soon as possible and
67 * should not be reused. This is set when an exclusive connection is used
68 * or a call ID counter overflows.
70 * The caching state may only be changed if the cache lock is held.
72 * There are two idle client connection expiry durations. If the total number
73 * of connections is below the reap threshold, we use the normal duration; if
74 * it's above, we use the fast duration.
77 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
79 #include <linux/slab.h>
80 #include <linux/idr.h>
81 #include <linux/timer.h>
82 #include <linux/sched/signal.h>
84 #include "ar-internal.h"
86 __read_mostly unsigned int rxrpc_max_client_connections = 1000;
87 __read_mostly unsigned int rxrpc_reap_client_connections = 900;
88 __read_mostly unsigned int rxrpc_conn_idle_client_expiry = 2 * 60 * HZ;
89 __read_mostly unsigned int rxrpc_conn_idle_client_fast_expiry = 2 * HZ;
92 * We use machine-unique IDs for our client connections.
94 DEFINE_IDR(rxrpc_client_conn_ids);
95 static DEFINE_SPINLOCK(rxrpc_conn_id_lock);
97 static void rxrpc_cull_active_client_conns(struct rxrpc_net *);
100 * Get a connection ID and epoch for a client connection from the global pool.
101 * The connection struct pointer is then recorded in the idr radix tree. The
102 * epoch doesn't change until the client is rebooted (or, at least, unless the
103 * module is unloaded).
105 static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn,
108 struct rxrpc_net *rxnet = conn->params.local->rxnet;
114 spin_lock(&rxrpc_conn_id_lock);
116 id = idr_alloc_cyclic(&rxrpc_client_conn_ids, conn,
117 1, 0x40000000, GFP_NOWAIT);
121 spin_unlock(&rxrpc_conn_id_lock);
124 conn->proto.epoch = rxnet->epoch;
125 conn->proto.cid = id << RXRPC_CIDSHIFT;
126 set_bit(RXRPC_CONN_HAS_IDR, &conn->flags);
127 _leave(" [CID %x]", conn->proto.cid);
131 spin_unlock(&rxrpc_conn_id_lock);
138 * Release a connection ID for a client connection from the global pool.
140 static void rxrpc_put_client_connection_id(struct rxrpc_connection *conn)
142 if (test_bit(RXRPC_CONN_HAS_IDR, &conn->flags)) {
143 spin_lock(&rxrpc_conn_id_lock);
144 idr_remove(&rxrpc_client_conn_ids,
145 conn->proto.cid >> RXRPC_CIDSHIFT);
146 spin_unlock(&rxrpc_conn_id_lock);
151 * Destroy the client connection ID tree.
153 void rxrpc_destroy_client_conn_ids(void)
155 struct rxrpc_connection *conn;
158 if (!idr_is_empty(&rxrpc_client_conn_ids)) {
159 idr_for_each_entry(&rxrpc_client_conn_ids, conn, id) {
160 pr_err("AF_RXRPC: Leaked client conn %p {%d}\n",
161 conn, atomic_read(&conn->usage));
166 idr_destroy(&rxrpc_client_conn_ids);
170 * Allocate a client connection.
172 static struct rxrpc_connection *
173 rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp)
175 struct rxrpc_connection *conn;
176 struct rxrpc_net *rxnet = cp->local->rxnet;
181 conn = rxrpc_alloc_connection(gfp);
183 _leave(" = -ENOMEM");
184 return ERR_PTR(-ENOMEM);
187 atomic_set(&conn->usage, 1);
189 __set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
191 __set_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags);
194 conn->out_clientflag = RXRPC_CLIENT_INITIATED;
195 conn->state = RXRPC_CONN_CLIENT;
196 conn->service_id = cp->service_id;
198 ret = rxrpc_get_client_connection_id(conn, gfp);
202 ret = rxrpc_init_client_conn_security(conn);
206 ret = conn->security->prime_packet_security(conn);
210 write_lock(&rxnet->conn_lock);
211 list_add_tail(&conn->proc_link, &rxnet->conn_proc_list);
212 write_unlock(&rxnet->conn_lock);
214 /* We steal the caller's peer ref. */
216 rxrpc_get_local(conn->params.local);
217 key_get(conn->params.key);
219 trace_rxrpc_conn(conn, rxrpc_conn_new_client, atomic_read(&conn->usage),
220 __builtin_return_address(0));
221 trace_rxrpc_client(conn, -1, rxrpc_client_alloc);
222 _leave(" = %p", conn);
226 conn->security->clear(conn);
228 rxrpc_put_client_connection_id(conn);
231 _leave(" = %d", ret);
236 * Determine if a connection may be reused.
238 static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn)
240 struct rxrpc_net *rxnet = conn->params.local->rxnet;
241 int id_cursor, id, distance, limit;
243 if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags))
246 if (conn->proto.epoch != rxnet->epoch)
247 goto mark_dont_reuse;
249 /* The IDR tree gets very expensive on memory if the connection IDs are
250 * widely scattered throughout the number space, so we shall want to
251 * kill off connections that, say, have an ID more than about four
252 * times the maximum number of client conns away from the current
253 * allocation point to try and keep the IDs concentrated.
255 id_cursor = idr_get_cursor(&rxrpc_client_conn_ids);
256 id = conn->proto.cid >> RXRPC_CIDSHIFT;
257 distance = id - id_cursor;
259 distance = -distance;
260 limit = max(rxrpc_max_client_connections * 4, 1024U);
261 if (distance > limit)
262 goto mark_dont_reuse;
267 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
273 * Create or find a client connection to use for a call.
275 * If we return with a connection, the call will be on its waiting list. It's
276 * left to the caller to assign a channel and wake up the call.
278 static int rxrpc_get_client_conn(struct rxrpc_call *call,
279 struct rxrpc_conn_parameters *cp,
280 struct sockaddr_rxrpc *srx,
283 struct rxrpc_connection *conn, *candidate = NULL;
284 struct rxrpc_local *local = cp->local;
285 struct rb_node *p, **pp, *parent;
289 _enter("{%d,%lx},", call->debug_id, call->user_call_ID);
291 cp->peer = rxrpc_lookup_peer(cp->local, srx, gfp);
295 call->cong_cwnd = cp->peer->cong_cwnd;
296 if (call->cong_cwnd >= call->cong_ssthresh)
297 call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE;
299 call->cong_mode = RXRPC_CALL_SLOW_START;
301 /* If the connection is not meant to be exclusive, search the available
302 * connections to see if the connection we want to use already exists.
304 if (!cp->exclusive) {
306 spin_lock(&local->client_conns_lock);
307 p = local->client_conns.rb_node;
309 conn = rb_entry(p, struct rxrpc_connection, client_node);
311 #define cmp(X) ((long)conn->params.X - (long)cp->X)
314 cmp(security_level) ?:
319 } else if (diff > 0) {
322 if (rxrpc_may_reuse_conn(conn) &&
323 rxrpc_get_connection_maybe(conn))
324 goto found_extant_conn;
325 /* The connection needs replacing. It's better
326 * to effect that when we have something to
327 * replace it with so that we don't have to
328 * rebalance the tree twice.
333 spin_unlock(&local->client_conns_lock);
336 /* There wasn't a connection yet or we need an exclusive connection.
337 * We need to create a candidate and then potentially redo the search
338 * in case we're racing with another thread also trying to connect on a
339 * shareable connection.
342 candidate = rxrpc_alloc_client_connection(cp, gfp);
343 if (IS_ERR(candidate)) {
344 ret = PTR_ERR(candidate);
348 /* Add the call to the new connection's waiting list in case we're
349 * going to have to wait for the connection to come live. It's our
350 * connection, so we want first dibs on the channel slots. We would
351 * normally have to take channel_lock but we do this before anyone else
352 * can see the connection.
354 list_add_tail(&call->chan_wait_link, &candidate->waiting_calls);
357 call->conn = candidate;
358 call->security_ix = candidate->security_ix;
359 call->service_id = candidate->service_id;
360 _leave(" = 0 [exclusive %d]", candidate->debug_id);
364 /* Publish the new connection for userspace to find. We need to redo
365 * the search before doing this lest we race with someone else adding a
366 * conflicting instance.
369 spin_lock(&local->client_conns_lock);
371 pp = &local->client_conns.rb_node;
375 conn = rb_entry(parent, struct rxrpc_connection, client_node);
377 #define cmp(X) ((long)conn->params.X - (long)candidate->params.X)
380 cmp(security_level) ?:
384 pp = &(*pp)->rb_left;
385 } else if (diff > 0) {
386 pp = &(*pp)->rb_right;
388 if (rxrpc_may_reuse_conn(conn) &&
389 rxrpc_get_connection_maybe(conn))
390 goto found_extant_conn;
391 /* The old connection is from an outdated epoch. */
392 _debug("replace conn");
393 clear_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags);
394 rb_replace_node(&conn->client_node,
395 &candidate->client_node,
396 &local->client_conns);
397 trace_rxrpc_client(conn, -1, rxrpc_client_replace);
398 goto candidate_published;
403 rb_link_node(&candidate->client_node, parent, pp);
404 rb_insert_color(&candidate->client_node, &local->client_conns);
407 set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags);
408 call->conn = candidate;
409 call->security_ix = candidate->security_ix;
410 call->service_id = candidate->service_id;
411 spin_unlock(&local->client_conns_lock);
412 _leave(" = 0 [new %d]", candidate->debug_id);
415 /* We come here if we found a suitable connection already in existence.
416 * Discard any candidate we may have allocated, and try to get a
417 * channel on this one.
420 _debug("found conn");
421 spin_unlock(&local->client_conns_lock);
424 trace_rxrpc_client(candidate, -1, rxrpc_client_duplicate);
425 rxrpc_put_connection(candidate);
429 spin_lock(&conn->channel_lock);
431 call->security_ix = conn->security_ix;
432 call->service_id = conn->service_id;
433 list_add(&call->chan_wait_link, &conn->waiting_calls);
434 spin_unlock(&conn->channel_lock);
435 _leave(" = 0 [extant %d]", conn->debug_id);
439 rxrpc_put_peer(cp->peer);
442 _leave(" = %d", ret);
447 * Activate a connection.
449 static void rxrpc_activate_conn(struct rxrpc_net *rxnet,
450 struct rxrpc_connection *conn)
452 if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) {
453 trace_rxrpc_client(conn, -1, rxrpc_client_to_upgrade);
454 conn->cache_state = RXRPC_CONN_CLIENT_UPGRADE;
456 trace_rxrpc_client(conn, -1, rxrpc_client_to_active);
457 conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE;
459 rxnet->nr_active_client_conns++;
460 list_move_tail(&conn->cache_link, &rxnet->active_client_conns);
464 * Attempt to animate a connection for a new call.
466 * If it's not exclusive, the connection is in the endpoint tree, and we're in
467 * the conn's list of those waiting to grab a channel. There is, however, a
468 * limit on the number of live connections allowed at any one time, so we may
469 * have to wait for capacity to become available.
471 * Note that a connection on the waiting queue might *also* have active
472 * channels if it has been culled to make space and then re-requested by a new
475 static void rxrpc_animate_client_conn(struct rxrpc_net *rxnet,
476 struct rxrpc_connection *conn)
478 unsigned int nr_conns;
480 _enter("%d,%d", conn->debug_id, conn->cache_state);
482 if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE ||
483 conn->cache_state == RXRPC_CONN_CLIENT_UPGRADE)
486 spin_lock(&rxnet->client_conn_cache_lock);
488 nr_conns = rxnet->nr_client_conns;
489 if (!test_and_set_bit(RXRPC_CONN_COUNTED, &conn->flags)) {
490 trace_rxrpc_client(conn, -1, rxrpc_client_count);
491 rxnet->nr_client_conns = nr_conns + 1;
494 switch (conn->cache_state) {
495 case RXRPC_CONN_CLIENT_ACTIVE:
496 case RXRPC_CONN_CLIENT_UPGRADE:
497 case RXRPC_CONN_CLIENT_WAITING:
500 case RXRPC_CONN_CLIENT_INACTIVE:
501 case RXRPC_CONN_CLIENT_CULLED:
502 case RXRPC_CONN_CLIENT_IDLE:
503 if (nr_conns >= rxrpc_max_client_connections)
504 goto wait_for_capacity;
512 spin_unlock(&rxnet->client_conn_cache_lock);
514 _leave(" [%d]", conn->cache_state);
519 rxrpc_activate_conn(rxnet, conn);
524 trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting);
525 conn->cache_state = RXRPC_CONN_CLIENT_WAITING;
526 list_move_tail(&conn->cache_link, &rxnet->waiting_client_conns);
531 * Deactivate a channel.
533 static void rxrpc_deactivate_one_channel(struct rxrpc_connection *conn,
534 unsigned int channel)
536 struct rxrpc_channel *chan = &conn->channels[channel];
538 rcu_assign_pointer(chan->call, NULL);
539 conn->active_chans &= ~(1 << channel);
543 * Assign a channel to the call at the front of the queue and wake the call up.
544 * We don't increment the callNumber counter until this number has been exposed
547 static void rxrpc_activate_one_channel(struct rxrpc_connection *conn,
548 unsigned int channel)
550 struct rxrpc_channel *chan = &conn->channels[channel];
551 struct rxrpc_call *call = list_entry(conn->waiting_calls.next,
552 struct rxrpc_call, chan_wait_link);
553 u32 call_id = chan->call_counter + 1;
555 trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate);
557 write_lock_bh(&call->state_lock);
558 if (!test_bit(RXRPC_CALL_TX_LASTQ, &call->flags))
559 call->state = RXRPC_CALL_CLIENT_SEND_REQUEST;
561 call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
562 write_unlock_bh(&call->state_lock);
564 rxrpc_see_call(call);
565 list_del_init(&call->chan_wait_link);
566 conn->active_chans |= 1 << channel;
567 call->peer = rxrpc_get_peer(conn->params.peer);
568 call->cid = conn->proto.cid | channel;
569 call->call_id = call_id;
571 trace_rxrpc_connect_call(call);
572 _net("CONNECT call %08x:%08x as call %d on conn %d",
573 call->cid, call->call_id, call->debug_id, conn->debug_id);
575 /* Paired with the read barrier in rxrpc_wait_for_channel(). This
576 * orders cid and epoch in the connection wrt to call_id without the
577 * need to take the channel_lock.
579 * We provisionally assign a callNumber at this point, but we don't
580 * confirm it until the call is about to be exposed.
582 * TODO: Pair with a barrier in the data_ready handler when that looks
583 * at the call ID through a connection channel.
586 chan->call_id = call_id;
587 rcu_assign_pointer(chan->call, call);
588 wake_up(&call->waitq);
592 * Assign channels and callNumbers to waiting calls with channel_lock
595 static void rxrpc_activate_channels_locked(struct rxrpc_connection *conn)
599 switch (conn->cache_state) {
600 case RXRPC_CONN_CLIENT_ACTIVE:
601 mask = RXRPC_ACTIVE_CHANS_MASK;
603 case RXRPC_CONN_CLIENT_UPGRADE:
610 while (!list_empty(&conn->waiting_calls) &&
611 (avail = ~conn->active_chans,
614 rxrpc_activate_one_channel(conn, __ffs(avail));
618 * Assign channels and callNumbers to waiting calls.
620 static void rxrpc_activate_channels(struct rxrpc_connection *conn)
622 _enter("%d", conn->debug_id);
624 trace_rxrpc_client(conn, -1, rxrpc_client_activate_chans);
626 if (conn->active_chans == RXRPC_ACTIVE_CHANS_MASK)
629 spin_lock(&conn->channel_lock);
630 rxrpc_activate_channels_locked(conn);
631 spin_unlock(&conn->channel_lock);
636 * Wait for a callNumber and a channel to be granted to a call.
638 static int rxrpc_wait_for_channel(struct rxrpc_call *call, gfp_t gfp)
642 _enter("%d", call->debug_id);
644 if (!call->call_id) {
645 DECLARE_WAITQUEUE(myself, current);
647 if (!gfpflags_allow_blocking(gfp)) {
652 add_wait_queue_exclusive(&call->waitq, &myself);
654 set_current_state(TASK_INTERRUPTIBLE);
657 if (signal_pending(current)) {
663 remove_wait_queue(&call->waitq, &myself);
664 __set_current_state(TASK_RUNNING);
667 /* Paired with the write barrier in rxrpc_activate_one_channel(). */
671 _leave(" = %d", ret);
676 * find a connection for a call
677 * - called in process context with IRQs enabled
679 int rxrpc_connect_call(struct rxrpc_call *call,
680 struct rxrpc_conn_parameters *cp,
681 struct sockaddr_rxrpc *srx,
684 struct rxrpc_net *rxnet = cp->local->rxnet;
687 _enter("{%d,%lx},", call->debug_id, call->user_call_ID);
689 rxrpc_discard_expired_client_conns(&rxnet->client_conn_reaper.work);
690 rxrpc_cull_active_client_conns(rxnet);
692 ret = rxrpc_get_client_conn(call, cp, srx, gfp);
696 rxrpc_animate_client_conn(rxnet, call->conn);
697 rxrpc_activate_channels(call->conn);
699 ret = rxrpc_wait_for_channel(call, gfp);
701 rxrpc_disconnect_client_call(call);
705 spin_lock_bh(&call->conn->params.peer->lock);
706 hlist_add_head(&call->error_link,
707 &call->conn->params.peer->error_targets);
708 spin_unlock_bh(&call->conn->params.peer->lock);
711 _leave(" = %d", ret);
716 * Note that a connection is about to be exposed to the world. Once it is
717 * exposed, we maintain an extra ref on it that stops it from being summarily
718 * discarded before it's (a) had a chance to deal with retransmission and (b)
719 * had a chance at re-use (the per-connection security negotiation is
722 static void rxrpc_expose_client_conn(struct rxrpc_connection *conn,
723 unsigned int channel)
725 if (!test_and_set_bit(RXRPC_CONN_EXPOSED, &conn->flags)) {
726 trace_rxrpc_client(conn, channel, rxrpc_client_exposed);
727 rxrpc_get_connection(conn);
732 * Note that a call, and thus a connection, is about to be exposed to the
735 void rxrpc_expose_client_call(struct rxrpc_call *call)
737 unsigned int channel = call->cid & RXRPC_CHANNELMASK;
738 struct rxrpc_connection *conn = call->conn;
739 struct rxrpc_channel *chan = &conn->channels[channel];
741 if (!test_and_set_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
742 /* Mark the call ID as being used. If the callNumber counter
743 * exceeds ~2 billion, we kill the connection after its
744 * outstanding calls have finished so that the counter doesn't
747 chan->call_counter++;
748 if (chan->call_counter >= INT_MAX)
749 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
750 rxrpc_expose_client_conn(conn, channel);
755 * Disconnect a client call.
757 void rxrpc_disconnect_client_call(struct rxrpc_call *call)
759 unsigned int channel = call->cid & RXRPC_CHANNELMASK;
760 struct rxrpc_connection *conn = call->conn;
761 struct rxrpc_channel *chan = &conn->channels[channel];
762 struct rxrpc_net *rxnet = rxrpc_net(sock_net(&call->socket->sk));
764 trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect);
767 spin_lock(&conn->channel_lock);
769 /* Calls that have never actually been assigned a channel can simply be
770 * discarded. If the conn didn't get used either, it will follow
771 * immediately unless someone else grabs it in the meantime.
773 if (!list_empty(&call->chan_wait_link)) {
774 _debug("call is waiting");
775 ASSERTCMP(call->call_id, ==, 0);
776 ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags));
777 list_del_init(&call->chan_wait_link);
779 trace_rxrpc_client(conn, channel, rxrpc_client_chan_unstarted);
781 /* We must deactivate or idle the connection if it's now
782 * waiting for nothing.
784 spin_lock(&rxnet->client_conn_cache_lock);
785 if (conn->cache_state == RXRPC_CONN_CLIENT_WAITING &&
786 list_empty(&conn->waiting_calls) &&
788 goto idle_connection;
792 ASSERTCMP(rcu_access_pointer(chan->call), ==, call);
794 /* If a client call was exposed to the world, we save the result for
797 * We use a barrier here so that the call number and abort code can be
798 * read without needing to take a lock.
800 * TODO: Make the incoming packet handler check this and handle
801 * terminal retransmission without requiring access to the call.
803 if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
804 _debug("exposed %u,%u", call->call_id, call->abort_code);
805 __rxrpc_disconnect_call(conn, call);
808 /* See if we can pass the channel directly to another call. */
809 if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE &&
810 !list_empty(&conn->waiting_calls)) {
811 trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
812 rxrpc_activate_one_channel(conn, channel);
816 /* Things are more complex and we need the cache lock. We might be
817 * able to simply idle the conn or it might now be lurking on the wait
818 * list. It might even get moved back to the active list whilst we're
819 * waiting for the lock.
821 spin_lock(&rxnet->client_conn_cache_lock);
823 switch (conn->cache_state) {
824 case RXRPC_CONN_CLIENT_UPGRADE:
825 /* Deal with termination of a service upgrade probe. */
826 if (test_bit(RXRPC_CONN_EXPOSED, &conn->flags)) {
827 clear_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags);
828 trace_rxrpc_client(conn, channel, rxrpc_client_to_active);
829 conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE;
830 rxrpc_activate_channels_locked(conn);
833 case RXRPC_CONN_CLIENT_ACTIVE:
834 if (list_empty(&conn->waiting_calls)) {
835 rxrpc_deactivate_one_channel(conn, channel);
836 if (!conn->active_chans) {
837 rxnet->nr_active_client_conns--;
838 goto idle_connection;
843 trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
844 rxrpc_activate_one_channel(conn, channel);
847 case RXRPC_CONN_CLIENT_CULLED:
848 rxrpc_deactivate_one_channel(conn, channel);
849 ASSERT(list_empty(&conn->waiting_calls));
850 if (!conn->active_chans)
851 goto idle_connection;
854 case RXRPC_CONN_CLIENT_WAITING:
855 rxrpc_deactivate_one_channel(conn, channel);
863 spin_unlock(&rxnet->client_conn_cache_lock);
865 spin_unlock(&conn->channel_lock);
866 rxrpc_put_connection(conn);
871 /* As no channels remain active, the connection gets deactivated
872 * immediately or moved to the idle list for a short while.
874 if (test_bit(RXRPC_CONN_EXPOSED, &conn->flags)) {
875 trace_rxrpc_client(conn, channel, rxrpc_client_to_idle);
876 conn->idle_timestamp = jiffies;
877 conn->cache_state = RXRPC_CONN_CLIENT_IDLE;
878 list_move_tail(&conn->cache_link, &rxnet->idle_client_conns);
879 if (rxnet->idle_client_conns.next == &conn->cache_link &&
880 !rxnet->kill_all_client_conns)
881 queue_delayed_work(rxrpc_workqueue,
882 &rxnet->client_conn_reaper,
883 rxrpc_conn_idle_client_expiry);
885 trace_rxrpc_client(conn, channel, rxrpc_client_to_inactive);
886 conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE;
887 list_del_init(&conn->cache_link);
893 * Clean up a dead client connection.
895 static struct rxrpc_connection *
896 rxrpc_put_one_client_conn(struct rxrpc_connection *conn)
898 struct rxrpc_connection *next = NULL;
899 struct rxrpc_local *local = conn->params.local;
900 struct rxrpc_net *rxnet = local->rxnet;
901 unsigned int nr_conns;
903 trace_rxrpc_client(conn, -1, rxrpc_client_cleanup);
905 if (test_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags)) {
906 spin_lock(&local->client_conns_lock);
907 if (test_and_clear_bit(RXRPC_CONN_IN_CLIENT_CONNS,
909 rb_erase(&conn->client_node, &local->client_conns);
910 spin_unlock(&local->client_conns_lock);
913 rxrpc_put_client_connection_id(conn);
915 ASSERTCMP(conn->cache_state, ==, RXRPC_CONN_CLIENT_INACTIVE);
917 if (test_bit(RXRPC_CONN_COUNTED, &conn->flags)) {
918 trace_rxrpc_client(conn, -1, rxrpc_client_uncount);
919 spin_lock(&rxnet->client_conn_cache_lock);
920 nr_conns = --rxnet->nr_client_conns;
922 if (nr_conns < rxrpc_max_client_connections &&
923 !list_empty(&rxnet->waiting_client_conns)) {
924 next = list_entry(rxnet->waiting_client_conns.next,
925 struct rxrpc_connection, cache_link);
926 rxrpc_get_connection(next);
927 rxrpc_activate_conn(rxnet, next);
930 spin_unlock(&rxnet->client_conn_cache_lock);
933 rxrpc_kill_connection(conn);
935 rxrpc_activate_channels(next);
937 /* We need to get rid of the temporary ref we took upon next, but we
938 * can't call rxrpc_put_connection() recursively.
944 * Clean up a dead client connections.
946 void rxrpc_put_client_conn(struct rxrpc_connection *conn)
948 const void *here = __builtin_return_address(0);
952 n = atomic_dec_return(&conn->usage);
953 trace_rxrpc_conn(conn, rxrpc_conn_put_client, n, here);
958 conn = rxrpc_put_one_client_conn(conn);
963 * Kill the longest-active client connections to make room for new ones.
965 static void rxrpc_cull_active_client_conns(struct rxrpc_net *rxnet)
967 struct rxrpc_connection *conn;
968 unsigned int nr_conns = rxnet->nr_client_conns;
969 unsigned int nr_active, limit;
973 ASSERTCMP(nr_conns, >=, 0);
974 if (nr_conns < rxrpc_max_client_connections) {
978 limit = rxrpc_reap_client_connections;
980 spin_lock(&rxnet->client_conn_cache_lock);
981 nr_active = rxnet->nr_active_client_conns;
983 while (nr_active > limit) {
984 ASSERT(!list_empty(&rxnet->active_client_conns));
985 conn = list_entry(rxnet->active_client_conns.next,
986 struct rxrpc_connection, cache_link);
987 ASSERTIFCMP(conn->cache_state != RXRPC_CONN_CLIENT_ACTIVE,
988 conn->cache_state, ==, RXRPC_CONN_CLIENT_UPGRADE);
990 if (list_empty(&conn->waiting_calls)) {
991 trace_rxrpc_client(conn, -1, rxrpc_client_to_culled);
992 conn->cache_state = RXRPC_CONN_CLIENT_CULLED;
993 list_del_init(&conn->cache_link);
995 trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting);
996 conn->cache_state = RXRPC_CONN_CLIENT_WAITING;
997 list_move_tail(&conn->cache_link,
998 &rxnet->waiting_client_conns);
1004 rxnet->nr_active_client_conns = nr_active;
1005 spin_unlock(&rxnet->client_conn_cache_lock);
1006 ASSERTCMP(nr_active, >=, 0);
1007 _leave(" [culled]");
1011 * Discard expired client connections from the idle list. Each conn in the
1012 * idle list has been exposed and holds an extra ref because of that.
1014 * This may be called from conn setup or from a work item so cannot be
1015 * considered non-reentrant.
1017 void rxrpc_discard_expired_client_conns(struct work_struct *work)
1019 struct rxrpc_connection *conn;
1020 struct rxrpc_net *rxnet =
1021 container_of(to_delayed_work(work),
1022 struct rxrpc_net, client_conn_reaper);
1023 unsigned long expiry, conn_expires_at, now;
1024 unsigned int nr_conns;
1025 bool did_discard = false;
1029 if (list_empty(&rxnet->idle_client_conns)) {
1034 /* Don't double up on the discarding */
1035 if (!spin_trylock(&rxnet->client_conn_discard_lock)) {
1036 _leave(" [already]");
1040 /* We keep an estimate of what the number of conns ought to be after
1041 * we've discarded some so that we don't overdo the discarding.
1043 nr_conns = rxnet->nr_client_conns;
1046 spin_lock(&rxnet->client_conn_cache_lock);
1048 if (list_empty(&rxnet->idle_client_conns))
1051 conn = list_entry(rxnet->idle_client_conns.next,
1052 struct rxrpc_connection, cache_link);
1053 ASSERT(test_bit(RXRPC_CONN_EXPOSED, &conn->flags));
1055 if (!rxnet->kill_all_client_conns) {
1056 /* If the number of connections is over the reap limit, we
1057 * expedite discard by reducing the expiry timeout. We must,
1058 * however, have at least a short grace period to be able to do
1059 * final-ACK or ABORT retransmission.
1061 expiry = rxrpc_conn_idle_client_expiry;
1062 if (nr_conns > rxrpc_reap_client_connections)
1063 expiry = rxrpc_conn_idle_client_fast_expiry;
1065 conn_expires_at = conn->idle_timestamp + expiry;
1067 now = READ_ONCE(jiffies);
1068 if (time_after(conn_expires_at, now))
1069 goto not_yet_expired;
1072 trace_rxrpc_client(conn, -1, rxrpc_client_discard);
1073 if (!test_and_clear_bit(RXRPC_CONN_EXPOSED, &conn->flags))
1075 conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE;
1076 list_del_init(&conn->cache_link);
1078 spin_unlock(&rxnet->client_conn_cache_lock);
1080 /* When we cleared the EXPOSED flag, we took on responsibility for the
1081 * reference that that had on the usage count. We deal with that here.
1082 * If someone re-sets the flag and re-gets the ref, that's fine.
1084 rxrpc_put_connection(conn);
1090 /* The connection at the front of the queue hasn't yet expired, so
1091 * schedule the work item for that point if we discarded something.
1093 * We don't worry if the work item is already scheduled - it can look
1094 * after rescheduling itself at a later time. We could cancel it, but
1095 * then things get messier.
1098 if (!rxnet->kill_all_client_conns)
1099 queue_delayed_work(rxrpc_workqueue,
1100 &rxnet->client_conn_reaper,
1101 conn_expires_at - now);
1104 spin_unlock(&rxnet->client_conn_cache_lock);
1105 spin_unlock(&rxnet->client_conn_discard_lock);
1110 * Preemptively destroy all the client connection records rather than waiting
1111 * for them to time out
1113 void rxrpc_destroy_all_client_connections(struct rxrpc_net *rxnet)
1117 spin_lock(&rxnet->client_conn_cache_lock);
1118 rxnet->kill_all_client_conns = true;
1119 spin_unlock(&rxnet->client_conn_cache_lock);
1121 cancel_delayed_work(&rxnet->client_conn_reaper);
1123 if (!queue_delayed_work(rxrpc_workqueue, &rxnet->client_conn_reaper, 0))
1124 _debug("destroy: queue failed");