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");