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 rxrpc_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) CULLED - The connection got summarily culled to try and free up
40 * capacity. Calls currently in progress on the connection are allowed to
41 * continue, but new calls will have to wait. There can be no waiters in
42 * this state - the conn would have to go to the WAITING state instead.
44 * (5) IDLE - The connection has no calls in progress upon it and must have
45 * been exposed to the world (ie. the EXPOSED flag must be set). When it
46 * expires, the EXPOSED flag is cleared and the connection transitions to
49 * The connection is on the rxrpc_idle_client_conns list which is kept in
50 * order of how soon they'll expire.
52 * There are flags of relevance to the cache:
54 * (1) EXPOSED - The connection ID got exposed to the world. If this flag is
55 * set, an extra ref is added to the connection preventing it from being
56 * reaped when it has no calls outstanding. This flag is cleared and the
57 * ref dropped when a conn is discarded from the idle list.
59 * This allows us to move terminal call state retransmission to the
60 * connection and to discard the call immediately we think it is done
61 * with. It also give us a chance to reuse the connection.
63 * (2) DONT_REUSE - The connection should be discarded as soon as possible and
64 * should not be reused. This is set when an exclusive connection is used
65 * or a call ID counter overflows.
67 * The caching state may only be changed if the cache lock is held.
69 * There are two idle client connection expiry durations. If the total number
70 * of connections is below the reap threshold, we use the normal duration; if
71 * it's above, we use the fast duration.
74 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
76 #include <linux/slab.h>
77 #include <linux/idr.h>
78 #include <linux/timer.h>
79 #include <linux/sched/signal.h>
81 #include "ar-internal.h"
83 __read_mostly unsigned int rxrpc_max_client_connections = 1000;
84 __read_mostly unsigned int rxrpc_reap_client_connections = 900;
85 __read_mostly unsigned int rxrpc_conn_idle_client_expiry = 2 * 60 * HZ;
86 __read_mostly unsigned int rxrpc_conn_idle_client_fast_expiry = 2 * HZ;
88 static unsigned int rxrpc_nr_client_conns;
89 static unsigned int rxrpc_nr_active_client_conns;
90 static __read_mostly bool rxrpc_kill_all_client_conns;
92 static DEFINE_SPINLOCK(rxrpc_client_conn_cache_lock);
93 static DEFINE_SPINLOCK(rxrpc_client_conn_discard_mutex);
94 static LIST_HEAD(rxrpc_waiting_client_conns);
95 static LIST_HEAD(rxrpc_active_client_conns);
96 static LIST_HEAD(rxrpc_idle_client_conns);
99 * We use machine-unique IDs for our client connections.
101 DEFINE_IDR(rxrpc_client_conn_ids);
102 static DEFINE_SPINLOCK(rxrpc_conn_id_lock);
104 static void rxrpc_cull_active_client_conns(void);
105 static void rxrpc_discard_expired_client_conns(struct work_struct *);
107 static DECLARE_DELAYED_WORK(rxrpc_client_conn_reap,
108 rxrpc_discard_expired_client_conns);
111 * Get a connection ID and epoch for a client connection from the global pool.
112 * The connection struct pointer is then recorded in the idr radix tree. The
113 * epoch doesn't change until the client is rebooted (or, at least, unless the
114 * module is unloaded).
116 static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn,
124 spin_lock(&rxrpc_conn_id_lock);
126 id = idr_alloc_cyclic(&rxrpc_client_conn_ids, conn,
127 1, 0x40000000, GFP_NOWAIT);
131 spin_unlock(&rxrpc_conn_id_lock);
134 conn->proto.epoch = rxrpc_epoch;
135 conn->proto.cid = id << RXRPC_CIDSHIFT;
136 set_bit(RXRPC_CONN_HAS_IDR, &conn->flags);
137 _leave(" [CID %x]", conn->proto.cid);
141 spin_unlock(&rxrpc_conn_id_lock);
148 * Release a connection ID for a client connection from the global pool.
150 static void rxrpc_put_client_connection_id(struct rxrpc_connection *conn)
152 if (test_bit(RXRPC_CONN_HAS_IDR, &conn->flags)) {
153 spin_lock(&rxrpc_conn_id_lock);
154 idr_remove(&rxrpc_client_conn_ids,
155 conn->proto.cid >> RXRPC_CIDSHIFT);
156 spin_unlock(&rxrpc_conn_id_lock);
161 * Destroy the client connection ID tree.
163 void rxrpc_destroy_client_conn_ids(void)
165 struct rxrpc_connection *conn;
168 if (!idr_is_empty(&rxrpc_client_conn_ids)) {
169 idr_for_each_entry(&rxrpc_client_conn_ids, conn, id) {
170 pr_err("AF_RXRPC: Leaked client conn %p {%d}\n",
171 conn, atomic_read(&conn->usage));
176 idr_destroy(&rxrpc_client_conn_ids);
180 * Allocate a client connection.
182 static struct rxrpc_connection *
183 rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp)
185 struct rxrpc_connection *conn;
190 conn = rxrpc_alloc_connection(gfp);
192 _leave(" = -ENOMEM");
193 return ERR_PTR(-ENOMEM);
196 atomic_set(&conn->usage, 1);
198 __set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
201 conn->out_clientflag = RXRPC_CLIENT_INITIATED;
202 conn->state = RXRPC_CONN_CLIENT;
204 ret = rxrpc_get_client_connection_id(conn, gfp);
208 ret = rxrpc_init_client_conn_security(conn);
212 ret = conn->security->prime_packet_security(conn);
216 write_lock(&rxrpc_connection_lock);
217 list_add_tail(&conn->proc_link, &rxrpc_connection_proc_list);
218 write_unlock(&rxrpc_connection_lock);
220 /* We steal the caller's peer ref. */
222 rxrpc_get_local(conn->params.local);
223 key_get(conn->params.key);
225 trace_rxrpc_conn(conn, rxrpc_conn_new_client, atomic_read(&conn->usage),
226 __builtin_return_address(0));
227 trace_rxrpc_client(conn, -1, rxrpc_client_alloc);
228 _leave(" = %p", conn);
232 conn->security->clear(conn);
234 rxrpc_put_client_connection_id(conn);
237 _leave(" = %d", ret);
242 * Determine if a connection may be reused.
244 static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn)
246 int id_cursor, id, distance, limit;
248 if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags))
251 if (conn->proto.epoch != rxrpc_epoch)
252 goto mark_dont_reuse;
254 /* The IDR tree gets very expensive on memory if the connection IDs are
255 * widely scattered throughout the number space, so we shall want to
256 * kill off connections that, say, have an ID more than about four
257 * times the maximum number of client conns away from the current
258 * allocation point to try and keep the IDs concentrated.
260 id_cursor = idr_get_cursor(&rxrpc_client_conn_ids);
261 id = conn->proto.cid >> RXRPC_CIDSHIFT;
262 distance = id - id_cursor;
264 distance = -distance;
265 limit = max(rxrpc_max_client_connections * 4, 1024U);
266 if (distance > limit)
267 goto mark_dont_reuse;
272 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
278 * Create or find a client connection to use for a call.
280 * If we return with a connection, the call will be on its waiting list. It's
281 * left to the caller to assign a channel and wake up the call.
283 static int rxrpc_get_client_conn(struct rxrpc_call *call,
284 struct rxrpc_conn_parameters *cp,
285 struct sockaddr_rxrpc *srx,
288 struct rxrpc_connection *conn, *candidate = NULL;
289 struct rxrpc_local *local = cp->local;
290 struct rb_node *p, **pp, *parent;
294 _enter("{%d,%lx},", call->debug_id, call->user_call_ID);
296 cp->peer = rxrpc_lookup_peer(cp->local, srx, gfp);
300 /* If the connection is not meant to be exclusive, search the available
301 * connections to see if the connection we want to use already exists.
303 if (!cp->exclusive) {
305 spin_lock(&local->client_conns_lock);
306 p = local->client_conns.rb_node;
308 conn = rb_entry(p, struct rxrpc_connection, client_node);
310 #define cmp(X) ((long)conn->params.X - (long)cp->X)
313 cmp(security_level));
317 } else if (diff > 0) {
320 if (rxrpc_may_reuse_conn(conn) &&
321 rxrpc_get_connection_maybe(conn))
322 goto found_extant_conn;
323 /* The connection needs replacing. It's better
324 * to effect that when we have something to
325 * replace it with so that we don't have to
326 * rebalance the tree twice.
331 spin_unlock(&local->client_conns_lock);
334 /* There wasn't a connection yet or we need an exclusive connection.
335 * We need to create a candidate and then potentially redo the search
336 * in case we're racing with another thread also trying to connect on a
337 * shareable connection.
340 candidate = rxrpc_alloc_client_connection(cp, gfp);
341 if (IS_ERR(candidate)) {
342 ret = PTR_ERR(candidate);
346 /* Add the call to the new connection's waiting list in case we're
347 * going to have to wait for the connection to come live. It's our
348 * connection, so we want first dibs on the channel slots. We would
349 * normally have to take channel_lock but we do this before anyone else
350 * can see the connection.
352 list_add_tail(&call->chan_wait_link, &candidate->waiting_calls);
355 call->conn = candidate;
356 call->security_ix = candidate->security_ix;
357 _leave(" = 0 [exclusive %d]", candidate->debug_id);
361 /* Publish the new connection for userspace to find. We need to redo
362 * the search before doing this lest we race with someone else adding a
363 * conflicting instance.
366 spin_lock(&local->client_conns_lock);
368 pp = &local->client_conns.rb_node;
372 conn = rb_entry(parent, struct rxrpc_connection, client_node);
374 #define cmp(X) ((long)conn->params.X - (long)candidate->params.X)
377 cmp(security_level));
380 pp = &(*pp)->rb_left;
381 } else if (diff > 0) {
382 pp = &(*pp)->rb_right;
384 if (rxrpc_may_reuse_conn(conn) &&
385 rxrpc_get_connection_maybe(conn))
386 goto found_extant_conn;
387 /* The old connection is from an outdated epoch. */
388 _debug("replace conn");
389 clear_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags);
390 rb_replace_node(&conn->client_node,
391 &candidate->client_node,
392 &local->client_conns);
393 trace_rxrpc_client(conn, -1, rxrpc_client_replace);
394 goto candidate_published;
399 rb_link_node(&candidate->client_node, parent, pp);
400 rb_insert_color(&candidate->client_node, &local->client_conns);
403 set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags);
404 call->conn = candidate;
405 call->security_ix = candidate->security_ix;
406 spin_unlock(&local->client_conns_lock);
407 _leave(" = 0 [new %d]", candidate->debug_id);
410 /* We come here if we found a suitable connection already in existence.
411 * Discard any candidate we may have allocated, and try to get a
412 * channel on this one.
415 _debug("found conn");
416 spin_unlock(&local->client_conns_lock);
419 trace_rxrpc_client(candidate, -1, rxrpc_client_duplicate);
420 rxrpc_put_connection(candidate);
424 spin_lock(&conn->channel_lock);
426 call->security_ix = conn->security_ix;
427 list_add(&call->chan_wait_link, &conn->waiting_calls);
428 spin_unlock(&conn->channel_lock);
429 _leave(" = 0 [extant %d]", conn->debug_id);
433 rxrpc_put_peer(cp->peer);
436 _leave(" = %d", ret);
441 * Activate a connection.
443 static void rxrpc_activate_conn(struct rxrpc_connection *conn)
445 trace_rxrpc_client(conn, -1, rxrpc_client_to_active);
446 conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE;
447 rxrpc_nr_active_client_conns++;
448 list_move_tail(&conn->cache_link, &rxrpc_active_client_conns);
452 * Attempt to animate a connection for a new call.
454 * If it's not exclusive, the connection is in the endpoint tree, and we're in
455 * the conn's list of those waiting to grab a channel. There is, however, a
456 * limit on the number of live connections allowed at any one time, so we may
457 * have to wait for capacity to become available.
459 * Note that a connection on the waiting queue might *also* have active
460 * channels if it has been culled to make space and then re-requested by a new
463 static void rxrpc_animate_client_conn(struct rxrpc_connection *conn)
465 unsigned int nr_conns;
467 _enter("%d,%d", conn->debug_id, conn->cache_state);
469 if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE)
472 spin_lock(&rxrpc_client_conn_cache_lock);
474 nr_conns = rxrpc_nr_client_conns;
475 if (!test_and_set_bit(RXRPC_CONN_COUNTED, &conn->flags)) {
476 trace_rxrpc_client(conn, -1, rxrpc_client_count);
477 rxrpc_nr_client_conns = nr_conns + 1;
480 switch (conn->cache_state) {
481 case RXRPC_CONN_CLIENT_ACTIVE:
482 case RXRPC_CONN_CLIENT_WAITING:
485 case RXRPC_CONN_CLIENT_INACTIVE:
486 case RXRPC_CONN_CLIENT_CULLED:
487 case RXRPC_CONN_CLIENT_IDLE:
488 if (nr_conns >= rxrpc_max_client_connections)
489 goto wait_for_capacity;
497 spin_unlock(&rxrpc_client_conn_cache_lock);
499 _leave(" [%d]", conn->cache_state);
504 rxrpc_activate_conn(conn);
509 trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting);
510 conn->cache_state = RXRPC_CONN_CLIENT_WAITING;
511 list_move_tail(&conn->cache_link, &rxrpc_waiting_client_conns);
516 * Deactivate a channel.
518 static void rxrpc_deactivate_one_channel(struct rxrpc_connection *conn,
519 unsigned int channel)
521 struct rxrpc_channel *chan = &conn->channels[channel];
523 rcu_assign_pointer(chan->call, NULL);
524 conn->active_chans &= ~(1 << channel);
528 * Assign a channel to the call at the front of the queue and wake the call up.
529 * We don't increment the callNumber counter until this number has been exposed
532 static void rxrpc_activate_one_channel(struct rxrpc_connection *conn,
533 unsigned int channel)
535 struct rxrpc_channel *chan = &conn->channels[channel];
536 struct rxrpc_call *call = list_entry(conn->waiting_calls.next,
537 struct rxrpc_call, chan_wait_link);
538 u32 call_id = chan->call_counter + 1;
540 trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate);
542 write_lock_bh(&call->state_lock);
543 call->state = RXRPC_CALL_CLIENT_SEND_REQUEST;
544 write_unlock_bh(&call->state_lock);
546 rxrpc_see_call(call);
547 list_del_init(&call->chan_wait_link);
548 conn->active_chans |= 1 << channel;
549 call->peer = rxrpc_get_peer(conn->params.peer);
550 call->cid = conn->proto.cid | channel;
551 call->call_id = call_id;
553 trace_rxrpc_connect_call(call);
554 _net("CONNECT call %08x:%08x as call %d on conn %d",
555 call->cid, call->call_id, call->debug_id, conn->debug_id);
557 /* Paired with the read barrier in rxrpc_wait_for_channel(). This
558 * orders cid and epoch in the connection wrt to call_id without the
559 * need to take the channel_lock.
561 * We provisionally assign a callNumber at this point, but we don't
562 * confirm it until the call is about to be exposed.
564 * TODO: Pair with a barrier in the data_ready handler when that looks
565 * at the call ID through a connection channel.
568 chan->call_id = call_id;
569 rcu_assign_pointer(chan->call, call);
570 wake_up(&call->waitq);
574 * Assign channels and callNumbers to waiting calls with channel_lock
577 static void rxrpc_activate_channels_locked(struct rxrpc_connection *conn)
581 switch (conn->cache_state) {
582 case RXRPC_CONN_CLIENT_ACTIVE:
583 mask = RXRPC_ACTIVE_CHANS_MASK;
589 while (!list_empty(&conn->waiting_calls) &&
590 (avail = ~conn->active_chans,
593 rxrpc_activate_one_channel(conn, __ffs(avail));
597 * Assign channels and callNumbers to waiting calls.
599 static void rxrpc_activate_channels(struct rxrpc_connection *conn)
601 _enter("%d", conn->debug_id);
603 trace_rxrpc_client(conn, -1, rxrpc_client_activate_chans);
605 if (conn->active_chans == RXRPC_ACTIVE_CHANS_MASK)
608 spin_lock(&conn->channel_lock);
609 rxrpc_activate_channels_locked(conn);
610 spin_unlock(&conn->channel_lock);
615 * Wait for a callNumber and a channel to be granted to a call.
617 static int rxrpc_wait_for_channel(struct rxrpc_call *call, gfp_t gfp)
621 _enter("%d", call->debug_id);
623 if (!call->call_id) {
624 DECLARE_WAITQUEUE(myself, current);
626 if (!gfpflags_allow_blocking(gfp)) {
631 add_wait_queue_exclusive(&call->waitq, &myself);
633 set_current_state(TASK_INTERRUPTIBLE);
636 if (signal_pending(current)) {
642 remove_wait_queue(&call->waitq, &myself);
643 __set_current_state(TASK_RUNNING);
646 /* Paired with the write barrier in rxrpc_activate_one_channel(). */
650 _leave(" = %d", ret);
655 * find a connection for a call
656 * - called in process context with IRQs enabled
658 int rxrpc_connect_call(struct rxrpc_call *call,
659 struct rxrpc_conn_parameters *cp,
660 struct sockaddr_rxrpc *srx,
665 _enter("{%d,%lx},", call->debug_id, call->user_call_ID);
667 rxrpc_discard_expired_client_conns(NULL);
668 rxrpc_cull_active_client_conns();
670 ret = rxrpc_get_client_conn(call, cp, srx, gfp);
674 rxrpc_animate_client_conn(call->conn);
675 rxrpc_activate_channels(call->conn);
677 ret = rxrpc_wait_for_channel(call, gfp);
679 rxrpc_disconnect_client_call(call);
681 _leave(" = %d", ret);
686 * Note that a connection is about to be exposed to the world. Once it is
687 * exposed, we maintain an extra ref on it that stops it from being summarily
688 * discarded before it's (a) had a chance to deal with retransmission and (b)
689 * had a chance at re-use (the per-connection security negotiation is
692 static void rxrpc_expose_client_conn(struct rxrpc_connection *conn,
693 unsigned int channel)
695 if (!test_and_set_bit(RXRPC_CONN_EXPOSED, &conn->flags)) {
696 trace_rxrpc_client(conn, channel, rxrpc_client_exposed);
697 rxrpc_get_connection(conn);
702 * Note that a call, and thus a connection, is about to be exposed to the
705 void rxrpc_expose_client_call(struct rxrpc_call *call)
707 unsigned int channel = call->cid & RXRPC_CHANNELMASK;
708 struct rxrpc_connection *conn = call->conn;
709 struct rxrpc_channel *chan = &conn->channels[channel];
711 if (!test_and_set_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
712 /* Mark the call ID as being used. If the callNumber counter
713 * exceeds ~2 billion, we kill the connection after its
714 * outstanding calls have finished so that the counter doesn't
717 chan->call_counter++;
718 if (chan->call_counter >= INT_MAX)
719 set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags);
720 rxrpc_expose_client_conn(conn, channel);
725 * Disconnect a client call.
727 void rxrpc_disconnect_client_call(struct rxrpc_call *call)
729 unsigned int channel = call->cid & RXRPC_CHANNELMASK;
730 struct rxrpc_connection *conn = call->conn;
731 struct rxrpc_channel *chan = &conn->channels[channel];
733 trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect);
736 spin_lock(&conn->channel_lock);
738 /* Calls that have never actually been assigned a channel can simply be
739 * discarded. If the conn didn't get used either, it will follow
740 * immediately unless someone else grabs it in the meantime.
742 if (!list_empty(&call->chan_wait_link)) {
743 _debug("call is waiting");
744 ASSERTCMP(call->call_id, ==, 0);
745 ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags));
746 list_del_init(&call->chan_wait_link);
748 trace_rxrpc_client(conn, channel, rxrpc_client_chan_unstarted);
750 /* We must deactivate or idle the connection if it's now
751 * waiting for nothing.
753 spin_lock(&rxrpc_client_conn_cache_lock);
754 if (conn->cache_state == RXRPC_CONN_CLIENT_WAITING &&
755 list_empty(&conn->waiting_calls) &&
757 goto idle_connection;
761 ASSERTCMP(rcu_access_pointer(chan->call), ==, call);
763 /* If a client call was exposed to the world, we save the result for
766 * We use a barrier here so that the call number and abort code can be
767 * read without needing to take a lock.
769 * TODO: Make the incoming packet handler check this and handle
770 * terminal retransmission without requiring access to the call.
772 if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
773 _debug("exposed %u,%u", call->call_id, call->abort_code);
774 __rxrpc_disconnect_call(conn, call);
777 /* See if we can pass the channel directly to another call. */
778 if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE &&
779 !list_empty(&conn->waiting_calls)) {
780 trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
781 rxrpc_activate_one_channel(conn, channel);
785 /* Things are more complex and we need the cache lock. We might be
786 * able to simply idle the conn or it might now be lurking on the wait
787 * list. It might even get moved back to the active list whilst we're
788 * waiting for the lock.
790 spin_lock(&rxrpc_client_conn_cache_lock);
792 switch (conn->cache_state) {
793 case RXRPC_CONN_CLIENT_ACTIVE:
794 if (list_empty(&conn->waiting_calls)) {
795 rxrpc_deactivate_one_channel(conn, channel);
796 if (!conn->active_chans) {
797 rxrpc_nr_active_client_conns--;
798 goto idle_connection;
803 trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass);
804 rxrpc_activate_one_channel(conn, channel);
807 case RXRPC_CONN_CLIENT_CULLED:
808 rxrpc_deactivate_one_channel(conn, channel);
809 ASSERT(list_empty(&conn->waiting_calls));
810 if (!conn->active_chans)
811 goto idle_connection;
814 case RXRPC_CONN_CLIENT_WAITING:
815 rxrpc_deactivate_one_channel(conn, channel);
823 spin_unlock(&rxrpc_client_conn_cache_lock);
825 spin_unlock(&conn->channel_lock);
826 rxrpc_put_connection(conn);
831 /* As no channels remain active, the connection gets deactivated
832 * immediately or moved to the idle list for a short while.
834 if (test_bit(RXRPC_CONN_EXPOSED, &conn->flags)) {
835 trace_rxrpc_client(conn, channel, rxrpc_client_to_idle);
836 conn->idle_timestamp = jiffies;
837 conn->cache_state = RXRPC_CONN_CLIENT_IDLE;
838 list_move_tail(&conn->cache_link, &rxrpc_idle_client_conns);
839 if (rxrpc_idle_client_conns.next == &conn->cache_link &&
840 !rxrpc_kill_all_client_conns)
841 queue_delayed_work(rxrpc_workqueue,
842 &rxrpc_client_conn_reap,
843 rxrpc_conn_idle_client_expiry);
845 trace_rxrpc_client(conn, channel, rxrpc_client_to_inactive);
846 conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE;
847 list_del_init(&conn->cache_link);
853 * Clean up a dead client connection.
855 static struct rxrpc_connection *
856 rxrpc_put_one_client_conn(struct rxrpc_connection *conn)
858 struct rxrpc_connection *next = NULL;
859 struct rxrpc_local *local = conn->params.local;
860 unsigned int nr_conns;
862 trace_rxrpc_client(conn, -1, rxrpc_client_cleanup);
864 if (test_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags)) {
865 spin_lock(&local->client_conns_lock);
866 if (test_and_clear_bit(RXRPC_CONN_IN_CLIENT_CONNS,
868 rb_erase(&conn->client_node, &local->client_conns);
869 spin_unlock(&local->client_conns_lock);
872 rxrpc_put_client_connection_id(conn);
874 ASSERTCMP(conn->cache_state, ==, RXRPC_CONN_CLIENT_INACTIVE);
876 if (test_bit(RXRPC_CONN_COUNTED, &conn->flags)) {
877 trace_rxrpc_client(conn, -1, rxrpc_client_uncount);
878 spin_lock(&rxrpc_client_conn_cache_lock);
879 nr_conns = --rxrpc_nr_client_conns;
881 if (nr_conns < rxrpc_max_client_connections &&
882 !list_empty(&rxrpc_waiting_client_conns)) {
883 next = list_entry(rxrpc_waiting_client_conns.next,
884 struct rxrpc_connection, cache_link);
885 rxrpc_get_connection(next);
886 rxrpc_activate_conn(next);
889 spin_unlock(&rxrpc_client_conn_cache_lock);
892 rxrpc_kill_connection(conn);
894 rxrpc_activate_channels(next);
896 /* We need to get rid of the temporary ref we took upon next, but we
897 * can't call rxrpc_put_connection() recursively.
903 * Clean up a dead client connections.
905 void rxrpc_put_client_conn(struct rxrpc_connection *conn)
907 const void *here = __builtin_return_address(0);
911 n = atomic_dec_return(&conn->usage);
912 trace_rxrpc_conn(conn, rxrpc_conn_put_client, n, here);
917 conn = rxrpc_put_one_client_conn(conn);
922 * Kill the longest-active client connections to make room for new ones.
924 static void rxrpc_cull_active_client_conns(void)
926 struct rxrpc_connection *conn;
927 unsigned int nr_conns = rxrpc_nr_client_conns;
928 unsigned int nr_active, limit;
932 ASSERTCMP(nr_conns, >=, 0);
933 if (nr_conns < rxrpc_max_client_connections) {
937 limit = rxrpc_reap_client_connections;
939 spin_lock(&rxrpc_client_conn_cache_lock);
940 nr_active = rxrpc_nr_active_client_conns;
942 while (nr_active > limit) {
943 ASSERT(!list_empty(&rxrpc_active_client_conns));
944 conn = list_entry(rxrpc_active_client_conns.next,
945 struct rxrpc_connection, cache_link);
946 ASSERTCMP(conn->cache_state, ==, RXRPC_CONN_CLIENT_ACTIVE);
948 if (list_empty(&conn->waiting_calls)) {
949 trace_rxrpc_client(conn, -1, rxrpc_client_to_culled);
950 conn->cache_state = RXRPC_CONN_CLIENT_CULLED;
951 list_del_init(&conn->cache_link);
953 trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting);
954 conn->cache_state = RXRPC_CONN_CLIENT_WAITING;
955 list_move_tail(&conn->cache_link,
956 &rxrpc_waiting_client_conns);
962 rxrpc_nr_active_client_conns = nr_active;
963 spin_unlock(&rxrpc_client_conn_cache_lock);
964 ASSERTCMP(nr_active, >=, 0);
969 * Discard expired client connections from the idle list. Each conn in the
970 * idle list has been exposed and holds an extra ref because of that.
972 * This may be called from conn setup or from a work item so cannot be
973 * considered non-reentrant.
975 static void rxrpc_discard_expired_client_conns(struct work_struct *work)
977 struct rxrpc_connection *conn;
978 unsigned long expiry, conn_expires_at, now;
979 unsigned int nr_conns;
980 bool did_discard = false;
982 _enter("%c", work ? 'w' : 'n');
984 if (list_empty(&rxrpc_idle_client_conns)) {
989 /* Don't double up on the discarding */
990 if (!spin_trylock(&rxrpc_client_conn_discard_mutex)) {
991 _leave(" [already]");
995 /* We keep an estimate of what the number of conns ought to be after
996 * we've discarded some so that we don't overdo the discarding.
998 nr_conns = rxrpc_nr_client_conns;
1001 spin_lock(&rxrpc_client_conn_cache_lock);
1003 if (list_empty(&rxrpc_idle_client_conns))
1006 conn = list_entry(rxrpc_idle_client_conns.next,
1007 struct rxrpc_connection, cache_link);
1008 ASSERT(test_bit(RXRPC_CONN_EXPOSED, &conn->flags));
1010 if (!rxrpc_kill_all_client_conns) {
1011 /* If the number of connections is over the reap limit, we
1012 * expedite discard by reducing the expiry timeout. We must,
1013 * however, have at least a short grace period to be able to do
1014 * final-ACK or ABORT retransmission.
1016 expiry = rxrpc_conn_idle_client_expiry;
1017 if (nr_conns > rxrpc_reap_client_connections)
1018 expiry = rxrpc_conn_idle_client_fast_expiry;
1020 conn_expires_at = conn->idle_timestamp + expiry;
1022 now = READ_ONCE(jiffies);
1023 if (time_after(conn_expires_at, now))
1024 goto not_yet_expired;
1027 trace_rxrpc_client(conn, -1, rxrpc_client_discard);
1028 if (!test_and_clear_bit(RXRPC_CONN_EXPOSED, &conn->flags))
1030 conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE;
1031 list_del_init(&conn->cache_link);
1033 spin_unlock(&rxrpc_client_conn_cache_lock);
1035 /* When we cleared the EXPOSED flag, we took on responsibility for the
1036 * reference that that had on the usage count. We deal with that here.
1037 * If someone re-sets the flag and re-gets the ref, that's fine.
1039 rxrpc_put_connection(conn);
1045 /* The connection at the front of the queue hasn't yet expired, so
1046 * schedule the work item for that point if we discarded something.
1048 * We don't worry if the work item is already scheduled - it can look
1049 * after rescheduling itself at a later time. We could cancel it, but
1050 * then things get messier.
1053 if (!rxrpc_kill_all_client_conns)
1054 queue_delayed_work(rxrpc_workqueue,
1055 &rxrpc_client_conn_reap,
1056 conn_expires_at - now);
1059 spin_unlock(&rxrpc_client_conn_cache_lock);
1060 spin_unlock(&rxrpc_client_conn_discard_mutex);
1065 * Preemptively destroy all the client connection records rather than waiting
1066 * for them to time out
1068 void __exit rxrpc_destroy_all_client_connections(void)
1072 spin_lock(&rxrpc_client_conn_cache_lock);
1073 rxrpc_kill_all_client_conns = true;
1074 spin_unlock(&rxrpc_client_conn_cache_lock);
1076 cancel_delayed_work(&rxrpc_client_conn_reap);
1078 if (!queue_delayed_work(rxrpc_workqueue, &rxrpc_client_conn_reap, 0))
1079 _debug("destroy: queue failed");