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 "ar-internal.h"
81 __read_mostly
unsigned int rxrpc_max_client_connections
= 1000;
82 __read_mostly
unsigned int rxrpc_reap_client_connections
= 900;
83 __read_mostly
unsigned int rxrpc_conn_idle_client_expiry
= 2 * 60 * HZ
;
84 __read_mostly
unsigned int rxrpc_conn_idle_client_fast_expiry
= 2 * HZ
;
86 static unsigned int rxrpc_nr_client_conns
;
87 static unsigned int rxrpc_nr_active_client_conns
;
88 static __read_mostly
bool rxrpc_kill_all_client_conns
;
90 static DEFINE_SPINLOCK(rxrpc_client_conn_cache_lock
);
91 static DEFINE_SPINLOCK(rxrpc_client_conn_discard_mutex
);
92 static LIST_HEAD(rxrpc_waiting_client_conns
);
93 static LIST_HEAD(rxrpc_active_client_conns
);
94 static LIST_HEAD(rxrpc_idle_client_conns
);
97 * We use machine-unique IDs for our client connections.
99 DEFINE_IDR(rxrpc_client_conn_ids
);
100 static DEFINE_SPINLOCK(rxrpc_conn_id_lock
);
102 static void rxrpc_cull_active_client_conns(void);
103 static void rxrpc_discard_expired_client_conns(struct work_struct
*);
105 static DECLARE_DELAYED_WORK(rxrpc_client_conn_reap
,
106 rxrpc_discard_expired_client_conns
);
109 * Get a connection ID and epoch for a client connection from the global pool.
110 * The connection struct pointer is then recorded in the idr radix tree. The
111 * epoch doesn't change until the client is rebooted (or, at least, unless the
112 * module is unloaded).
114 static int rxrpc_get_client_connection_id(struct rxrpc_connection
*conn
,
122 spin_lock(&rxrpc_conn_id_lock
);
124 id
= idr_alloc_cyclic(&rxrpc_client_conn_ids
, conn
,
125 1, 0x40000000, GFP_NOWAIT
);
129 spin_unlock(&rxrpc_conn_id_lock
);
132 conn
->proto
.epoch
= rxrpc_epoch
;
133 conn
->proto
.cid
= id
<< RXRPC_CIDSHIFT
;
134 set_bit(RXRPC_CONN_HAS_IDR
, &conn
->flags
);
135 _leave(" [CID %x]", conn
->proto
.cid
);
139 spin_unlock(&rxrpc_conn_id_lock
);
146 * Release a connection ID for a client connection from the global pool.
148 static void rxrpc_put_client_connection_id(struct rxrpc_connection
*conn
)
150 if (test_bit(RXRPC_CONN_HAS_IDR
, &conn
->flags
)) {
151 spin_lock(&rxrpc_conn_id_lock
);
152 idr_remove(&rxrpc_client_conn_ids
,
153 conn
->proto
.cid
>> RXRPC_CIDSHIFT
);
154 spin_unlock(&rxrpc_conn_id_lock
);
159 * Destroy the client connection ID tree.
161 void rxrpc_destroy_client_conn_ids(void)
163 struct rxrpc_connection
*conn
;
166 if (!idr_is_empty(&rxrpc_client_conn_ids
)) {
167 idr_for_each_entry(&rxrpc_client_conn_ids
, conn
, id
) {
168 pr_err("AF_RXRPC: Leaked client conn %p {%d}\n",
169 conn
, atomic_read(&conn
->usage
));
174 idr_destroy(&rxrpc_client_conn_ids
);
178 * Allocate a client connection.
180 static struct rxrpc_connection
*
181 rxrpc_alloc_client_connection(struct rxrpc_conn_parameters
*cp
, gfp_t gfp
)
183 struct rxrpc_connection
*conn
;
188 conn
= rxrpc_alloc_connection(gfp
);
190 _leave(" = -ENOMEM");
191 return ERR_PTR(-ENOMEM
);
194 atomic_set(&conn
->usage
, 1);
196 __set_bit(RXRPC_CONN_DONT_REUSE
, &conn
->flags
);
199 conn
->out_clientflag
= RXRPC_CLIENT_INITIATED
;
200 conn
->state
= RXRPC_CONN_CLIENT
;
202 ret
= rxrpc_get_client_connection_id(conn
, gfp
);
206 ret
= rxrpc_init_client_conn_security(conn
);
210 ret
= conn
->security
->prime_packet_security(conn
);
214 write_lock(&rxrpc_connection_lock
);
215 list_add_tail(&conn
->proc_link
, &rxrpc_connection_proc_list
);
216 write_unlock(&rxrpc_connection_lock
);
218 /* We steal the caller's peer ref. */
220 rxrpc_get_local(conn
->params
.local
);
221 key_get(conn
->params
.key
);
223 trace_rxrpc_conn(conn
, rxrpc_conn_new_client
, atomic_read(&conn
->usage
),
224 __builtin_return_address(0));
225 trace_rxrpc_client(conn
, -1, rxrpc_client_alloc
);
226 _leave(" = %p", conn
);
230 conn
->security
->clear(conn
);
232 rxrpc_put_client_connection_id(conn
);
235 _leave(" = %d", ret
);
240 * Determine if a connection may be reused.
242 static bool rxrpc_may_reuse_conn(struct rxrpc_connection
*conn
)
244 int id_cursor
, id
, distance
, limit
;
246 if (test_bit(RXRPC_CONN_DONT_REUSE
, &conn
->flags
))
249 if (conn
->proto
.epoch
!= rxrpc_epoch
)
250 goto mark_dont_reuse
;
252 /* The IDR tree gets very expensive on memory if the connection IDs are
253 * widely scattered throughout the number space, so we shall want to
254 * kill off connections that, say, have an ID more than about four
255 * times the maximum number of client conns away from the current
256 * allocation point to try and keep the IDs concentrated.
258 id_cursor
= idr_get_cursor(&rxrpc_client_conn_ids
);
259 id
= conn
->proto
.cid
>> RXRPC_CIDSHIFT
;
260 distance
= id
- id_cursor
;
262 distance
= -distance
;
263 limit
= max(rxrpc_max_client_connections
* 4, 1024U);
264 if (distance
> limit
)
265 goto mark_dont_reuse
;
270 set_bit(RXRPC_CONN_DONT_REUSE
, &conn
->flags
);
276 * Create or find a client connection to use for a call.
278 * If we return with a connection, the call will be on its waiting list. It's
279 * left to the caller to assign a channel and wake up the call.
281 static int rxrpc_get_client_conn(struct rxrpc_call
*call
,
282 struct rxrpc_conn_parameters
*cp
,
283 struct sockaddr_rxrpc
*srx
,
286 struct rxrpc_connection
*conn
, *candidate
= NULL
;
287 struct rxrpc_local
*local
= cp
->local
;
288 struct rb_node
*p
, **pp
, *parent
;
292 _enter("{%d,%lx},", call
->debug_id
, call
->user_call_ID
);
294 cp
->peer
= rxrpc_lookup_peer(cp
->local
, srx
, gfp
);
298 /* If the connection is not meant to be exclusive, search the available
299 * connections to see if the connection we want to use already exists.
301 if (!cp
->exclusive
) {
303 spin_lock(&local
->client_conns_lock
);
304 p
= local
->client_conns
.rb_node
;
306 conn
= rb_entry(p
, struct rxrpc_connection
, client_node
);
308 #define cmp(X) ((long)conn->params.X - (long)cp->X)
311 cmp(security_level
));
315 } else if (diff
> 0) {
318 if (rxrpc_may_reuse_conn(conn
) &&
319 rxrpc_get_connection_maybe(conn
))
320 goto found_extant_conn
;
321 /* The connection needs replacing. It's better
322 * to effect that when we have something to
323 * replace it with so that we don't have to
324 * rebalance the tree twice.
329 spin_unlock(&local
->client_conns_lock
);
332 /* There wasn't a connection yet or we need an exclusive connection.
333 * We need to create a candidate and then potentially redo the search
334 * in case we're racing with another thread also trying to connect on a
335 * shareable connection.
338 candidate
= rxrpc_alloc_client_connection(cp
, gfp
);
339 if (IS_ERR(candidate
)) {
340 ret
= PTR_ERR(candidate
);
344 /* Add the call to the new connection's waiting list in case we're
345 * going to have to wait for the connection to come live. It's our
346 * connection, so we want first dibs on the channel slots. We would
347 * normally have to take channel_lock but we do this before anyone else
348 * can see the connection.
350 list_add_tail(&call
->chan_wait_link
, &candidate
->waiting_calls
);
353 call
->conn
= candidate
;
354 call
->security_ix
= candidate
->security_ix
;
355 _leave(" = 0 [exclusive %d]", candidate
->debug_id
);
359 /* Publish the new connection for userspace to find. We need to redo
360 * the search before doing this lest we race with someone else adding a
361 * conflicting instance.
364 spin_lock(&local
->client_conns_lock
);
366 pp
= &local
->client_conns
.rb_node
;
370 conn
= rb_entry(parent
, struct rxrpc_connection
, client_node
);
372 #define cmp(X) ((long)conn->params.X - (long)candidate->params.X)
375 cmp(security_level
));
378 pp
= &(*pp
)->rb_left
;
379 } else if (diff
> 0) {
380 pp
= &(*pp
)->rb_right
;
382 if (rxrpc_may_reuse_conn(conn
) &&
383 rxrpc_get_connection_maybe(conn
))
384 goto found_extant_conn
;
385 /* The old connection is from an outdated epoch. */
386 _debug("replace conn");
387 clear_bit(RXRPC_CONN_IN_CLIENT_CONNS
, &conn
->flags
);
388 rb_replace_node(&conn
->client_node
,
389 &candidate
->client_node
,
390 &local
->client_conns
);
391 trace_rxrpc_client(conn
, -1, rxrpc_client_replace
);
392 goto candidate_published
;
397 rb_link_node(&candidate
->client_node
, parent
, pp
);
398 rb_insert_color(&candidate
->client_node
, &local
->client_conns
);
401 set_bit(RXRPC_CONN_IN_CLIENT_CONNS
, &candidate
->flags
);
402 call
->conn
= candidate
;
403 call
->security_ix
= candidate
->security_ix
;
404 spin_unlock(&local
->client_conns_lock
);
405 _leave(" = 0 [new %d]", candidate
->debug_id
);
408 /* We come here if we found a suitable connection already in existence.
409 * Discard any candidate we may have allocated, and try to get a
410 * channel on this one.
413 _debug("found conn");
414 spin_unlock(&local
->client_conns_lock
);
417 trace_rxrpc_client(candidate
, -1, rxrpc_client_duplicate
);
418 rxrpc_put_connection(candidate
);
422 spin_lock(&conn
->channel_lock
);
424 call
->security_ix
= conn
->security_ix
;
425 list_add(&call
->chan_wait_link
, &conn
->waiting_calls
);
426 spin_unlock(&conn
->channel_lock
);
427 _leave(" = 0 [extant %d]", conn
->debug_id
);
431 rxrpc_put_peer(cp
->peer
);
434 _leave(" = %d", ret
);
439 * Activate a connection.
441 static void rxrpc_activate_conn(struct rxrpc_connection
*conn
)
443 trace_rxrpc_client(conn
, -1, rxrpc_client_to_active
);
444 conn
->cache_state
= RXRPC_CONN_CLIENT_ACTIVE
;
445 rxrpc_nr_active_client_conns
++;
446 list_move_tail(&conn
->cache_link
, &rxrpc_active_client_conns
);
450 * Attempt to animate a connection for a new call.
452 * If it's not exclusive, the connection is in the endpoint tree, and we're in
453 * the conn's list of those waiting to grab a channel. There is, however, a
454 * limit on the number of live connections allowed at any one time, so we may
455 * have to wait for capacity to become available.
457 * Note that a connection on the waiting queue might *also* have active
458 * channels if it has been culled to make space and then re-requested by a new
461 static void rxrpc_animate_client_conn(struct rxrpc_connection
*conn
)
463 unsigned int nr_conns
;
465 _enter("%d,%d", conn
->debug_id
, conn
->cache_state
);
467 if (conn
->cache_state
== RXRPC_CONN_CLIENT_ACTIVE
)
470 spin_lock(&rxrpc_client_conn_cache_lock
);
472 nr_conns
= rxrpc_nr_client_conns
;
473 if (!test_and_set_bit(RXRPC_CONN_COUNTED
, &conn
->flags
)) {
474 trace_rxrpc_client(conn
, -1, rxrpc_client_count
);
475 rxrpc_nr_client_conns
= nr_conns
+ 1;
478 switch (conn
->cache_state
) {
479 case RXRPC_CONN_CLIENT_ACTIVE
:
480 case RXRPC_CONN_CLIENT_WAITING
:
483 case RXRPC_CONN_CLIENT_INACTIVE
:
484 case RXRPC_CONN_CLIENT_CULLED
:
485 case RXRPC_CONN_CLIENT_IDLE
:
486 if (nr_conns
>= rxrpc_max_client_connections
)
487 goto wait_for_capacity
;
495 spin_unlock(&rxrpc_client_conn_cache_lock
);
497 _leave(" [%d]", conn
->cache_state
);
502 rxrpc_activate_conn(conn
);
507 trace_rxrpc_client(conn
, -1, rxrpc_client_to_waiting
);
508 conn
->cache_state
= RXRPC_CONN_CLIENT_WAITING
;
509 list_move_tail(&conn
->cache_link
, &rxrpc_waiting_client_conns
);
514 * Deactivate a channel.
516 static void rxrpc_deactivate_one_channel(struct rxrpc_connection
*conn
,
517 unsigned int channel
)
519 struct rxrpc_channel
*chan
= &conn
->channels
[channel
];
521 rcu_assign_pointer(chan
->call
, NULL
);
522 conn
->active_chans
&= ~(1 << channel
);
526 * Assign a channel to the call at the front of the queue and wake the call up.
527 * We don't increment the callNumber counter until this number has been exposed
530 static void rxrpc_activate_one_channel(struct rxrpc_connection
*conn
,
531 unsigned int channel
)
533 struct rxrpc_channel
*chan
= &conn
->channels
[channel
];
534 struct rxrpc_call
*call
= list_entry(conn
->waiting_calls
.next
,
535 struct rxrpc_call
, chan_wait_link
);
536 u32 call_id
= chan
->call_counter
+ 1;
538 trace_rxrpc_client(conn
, channel
, rxrpc_client_chan_activate
);
540 write_lock_bh(&call
->state_lock
);
541 call
->state
= RXRPC_CALL_CLIENT_SEND_REQUEST
;
542 write_unlock_bh(&call
->state_lock
);
544 rxrpc_see_call(call
);
545 list_del_init(&call
->chan_wait_link
);
546 conn
->active_chans
|= 1 << channel
;
547 call
->peer
= rxrpc_get_peer(conn
->params
.peer
);
548 call
->cid
= conn
->proto
.cid
| channel
;
549 call
->call_id
= call_id
;
551 _net("CONNECT call %08x:%08x as call %d on conn %d",
552 call
->cid
, call
->call_id
, call
->debug_id
, conn
->debug_id
);
554 /* Paired with the read barrier in rxrpc_wait_for_channel(). This
555 * orders cid and epoch in the connection wrt to call_id without the
556 * need to take the channel_lock.
558 * We provisionally assign a callNumber at this point, but we don't
559 * confirm it until the call is about to be exposed.
561 * TODO: Pair with a barrier in the data_ready handler when that looks
562 * at the call ID through a connection channel.
565 chan
->call_id
= call_id
;
566 rcu_assign_pointer(chan
->call
, call
);
567 wake_up(&call
->waitq
);
571 * Assign channels and callNumbers to waiting calls with channel_lock
574 static void rxrpc_activate_channels_locked(struct rxrpc_connection
*conn
)
578 switch (conn
->cache_state
) {
579 case RXRPC_CONN_CLIENT_ACTIVE
:
580 mask
= RXRPC_ACTIVE_CHANS_MASK
;
586 while (!list_empty(&conn
->waiting_calls
) &&
587 (avail
= ~conn
->active_chans
,
590 rxrpc_activate_one_channel(conn
, __ffs(avail
));
594 * Assign channels and callNumbers to waiting calls.
596 static void rxrpc_activate_channels(struct rxrpc_connection
*conn
)
598 _enter("%d", conn
->debug_id
);
600 trace_rxrpc_client(conn
, -1, rxrpc_client_activate_chans
);
602 if (conn
->active_chans
== RXRPC_ACTIVE_CHANS_MASK
)
605 spin_lock(&conn
->channel_lock
);
606 rxrpc_activate_channels_locked(conn
);
607 spin_unlock(&conn
->channel_lock
);
612 * Wait for a callNumber and a channel to be granted to a call.
614 static int rxrpc_wait_for_channel(struct rxrpc_call
*call
, gfp_t gfp
)
618 _enter("%d", call
->debug_id
);
620 if (!call
->call_id
) {
621 DECLARE_WAITQUEUE(myself
, current
);
623 if (!gfpflags_allow_blocking(gfp
)) {
628 add_wait_queue_exclusive(&call
->waitq
, &myself
);
630 set_current_state(TASK_INTERRUPTIBLE
);
633 if (signal_pending(current
)) {
639 remove_wait_queue(&call
->waitq
, &myself
);
640 __set_current_state(TASK_RUNNING
);
643 /* Paired with the write barrier in rxrpc_activate_one_channel(). */
647 _leave(" = %d", ret
);
652 * find a connection for a call
653 * - called in process context with IRQs enabled
655 int rxrpc_connect_call(struct rxrpc_call
*call
,
656 struct rxrpc_conn_parameters
*cp
,
657 struct sockaddr_rxrpc
*srx
,
662 _enter("{%d,%lx},", call
->debug_id
, call
->user_call_ID
);
664 rxrpc_discard_expired_client_conns(NULL
);
665 rxrpc_cull_active_client_conns();
667 ret
= rxrpc_get_client_conn(call
, cp
, srx
, gfp
);
671 rxrpc_animate_client_conn(call
->conn
);
672 rxrpc_activate_channels(call
->conn
);
674 ret
= rxrpc_wait_for_channel(call
, gfp
);
676 rxrpc_disconnect_client_call(call
);
678 _leave(" = %d", ret
);
683 * Note that a connection is about to be exposed to the world. Once it is
684 * exposed, we maintain an extra ref on it that stops it from being summarily
685 * discarded before it's (a) had a chance to deal with retransmission and (b)
686 * had a chance at re-use (the per-connection security negotiation is
689 static void rxrpc_expose_client_conn(struct rxrpc_connection
*conn
,
690 unsigned int channel
)
692 if (!test_and_set_bit(RXRPC_CONN_EXPOSED
, &conn
->flags
)) {
693 trace_rxrpc_client(conn
, channel
, rxrpc_client_exposed
);
694 rxrpc_get_connection(conn
);
699 * Note that a call, and thus a connection, is about to be exposed to the
702 void rxrpc_expose_client_call(struct rxrpc_call
*call
)
704 unsigned int channel
= call
->cid
& RXRPC_CHANNELMASK
;
705 struct rxrpc_connection
*conn
= call
->conn
;
706 struct rxrpc_channel
*chan
= &conn
->channels
[channel
];
708 if (!test_and_set_bit(RXRPC_CALL_EXPOSED
, &call
->flags
)) {
709 /* Mark the call ID as being used. If the callNumber counter
710 * exceeds ~2 billion, we kill the connection after its
711 * outstanding calls have finished so that the counter doesn't
714 chan
->call_counter
++;
715 if (chan
->call_counter
>= INT_MAX
)
716 set_bit(RXRPC_CONN_DONT_REUSE
, &conn
->flags
);
717 rxrpc_expose_client_conn(conn
, channel
);
722 * Disconnect a client call.
724 void rxrpc_disconnect_client_call(struct rxrpc_call
*call
)
726 unsigned int channel
= call
->cid
& RXRPC_CHANNELMASK
;
727 struct rxrpc_connection
*conn
= call
->conn
;
728 struct rxrpc_channel
*chan
= &conn
->channels
[channel
];
730 trace_rxrpc_client(conn
, channel
, rxrpc_client_chan_disconnect
);
733 spin_lock(&conn
->channel_lock
);
735 /* Calls that have never actually been assigned a channel can simply be
736 * discarded. If the conn didn't get used either, it will follow
737 * immediately unless someone else grabs it in the meantime.
739 if (!list_empty(&call
->chan_wait_link
)) {
740 _debug("call is waiting");
741 ASSERTCMP(call
->call_id
, ==, 0);
742 ASSERT(!test_bit(RXRPC_CALL_EXPOSED
, &call
->flags
));
743 list_del_init(&call
->chan_wait_link
);
745 trace_rxrpc_client(conn
, channel
, rxrpc_client_chan_unstarted
);
747 /* We must deactivate or idle the connection if it's now
748 * waiting for nothing.
750 spin_lock(&rxrpc_client_conn_cache_lock
);
751 if (conn
->cache_state
== RXRPC_CONN_CLIENT_WAITING
&&
752 list_empty(&conn
->waiting_calls
) &&
754 goto idle_connection
;
758 ASSERTCMP(rcu_access_pointer(chan
->call
), ==, call
);
760 /* If a client call was exposed to the world, we save the result for
763 * We use a barrier here so that the call number and abort code can be
764 * read without needing to take a lock.
766 * TODO: Make the incoming packet handler check this and handle
767 * terminal retransmission without requiring access to the call.
769 if (test_bit(RXRPC_CALL_EXPOSED
, &call
->flags
)) {
770 _debug("exposed %u,%u", call
->call_id
, call
->abort_code
);
771 __rxrpc_disconnect_call(conn
, call
);
774 /* See if we can pass the channel directly to another call. */
775 if (conn
->cache_state
== RXRPC_CONN_CLIENT_ACTIVE
&&
776 !list_empty(&conn
->waiting_calls
)) {
777 trace_rxrpc_client(conn
, channel
, rxrpc_client_chan_pass
);
778 rxrpc_activate_one_channel(conn
, channel
);
782 /* Things are more complex and we need the cache lock. We might be
783 * able to simply idle the conn or it might now be lurking on the wait
784 * list. It might even get moved back to the active list whilst we're
785 * waiting for the lock.
787 spin_lock(&rxrpc_client_conn_cache_lock
);
789 switch (conn
->cache_state
) {
790 case RXRPC_CONN_CLIENT_ACTIVE
:
791 if (list_empty(&conn
->waiting_calls
)) {
792 rxrpc_deactivate_one_channel(conn
, channel
);
793 if (!conn
->active_chans
) {
794 rxrpc_nr_active_client_conns
--;
795 goto idle_connection
;
800 trace_rxrpc_client(conn
, channel
, rxrpc_client_chan_pass
);
801 rxrpc_activate_one_channel(conn
, channel
);
804 case RXRPC_CONN_CLIENT_CULLED
:
805 rxrpc_deactivate_one_channel(conn
, channel
);
806 ASSERT(list_empty(&conn
->waiting_calls
));
807 if (!conn
->active_chans
)
808 goto idle_connection
;
811 case RXRPC_CONN_CLIENT_WAITING
:
812 rxrpc_deactivate_one_channel(conn
, channel
);
820 spin_unlock(&rxrpc_client_conn_cache_lock
);
822 spin_unlock(&conn
->channel_lock
);
823 rxrpc_put_connection(conn
);
828 /* As no channels remain active, the connection gets deactivated
829 * immediately or moved to the idle list for a short while.
831 if (test_bit(RXRPC_CONN_EXPOSED
, &conn
->flags
)) {
832 trace_rxrpc_client(conn
, channel
, rxrpc_client_to_idle
);
833 conn
->idle_timestamp
= jiffies
;
834 conn
->cache_state
= RXRPC_CONN_CLIENT_IDLE
;
835 list_move_tail(&conn
->cache_link
, &rxrpc_idle_client_conns
);
836 if (rxrpc_idle_client_conns
.next
== &conn
->cache_link
&&
837 !rxrpc_kill_all_client_conns
)
838 queue_delayed_work(rxrpc_workqueue
,
839 &rxrpc_client_conn_reap
,
840 rxrpc_conn_idle_client_expiry
);
842 trace_rxrpc_client(conn
, channel
, rxrpc_client_to_inactive
);
843 conn
->cache_state
= RXRPC_CONN_CLIENT_INACTIVE
;
844 list_del_init(&conn
->cache_link
);
850 * Clean up a dead client connection.
852 static struct rxrpc_connection
*
853 rxrpc_put_one_client_conn(struct rxrpc_connection
*conn
)
855 struct rxrpc_connection
*next
= NULL
;
856 struct rxrpc_local
*local
= conn
->params
.local
;
857 unsigned int nr_conns
;
859 trace_rxrpc_client(conn
, -1, rxrpc_client_cleanup
);
861 if (test_bit(RXRPC_CONN_IN_CLIENT_CONNS
, &conn
->flags
)) {
862 spin_lock(&local
->client_conns_lock
);
863 if (test_and_clear_bit(RXRPC_CONN_IN_CLIENT_CONNS
,
865 rb_erase(&conn
->client_node
, &local
->client_conns
);
866 spin_unlock(&local
->client_conns_lock
);
869 rxrpc_put_client_connection_id(conn
);
871 ASSERTCMP(conn
->cache_state
, ==, RXRPC_CONN_CLIENT_INACTIVE
);
873 if (test_bit(RXRPC_CONN_COUNTED
, &conn
->flags
)) {
874 trace_rxrpc_client(conn
, -1, rxrpc_client_uncount
);
875 spin_lock(&rxrpc_client_conn_cache_lock
);
876 nr_conns
= --rxrpc_nr_client_conns
;
878 if (nr_conns
< rxrpc_max_client_connections
&&
879 !list_empty(&rxrpc_waiting_client_conns
)) {
880 next
= list_entry(rxrpc_waiting_client_conns
.next
,
881 struct rxrpc_connection
, cache_link
);
882 rxrpc_get_connection(next
);
883 rxrpc_activate_conn(next
);
886 spin_unlock(&rxrpc_client_conn_cache_lock
);
889 rxrpc_kill_connection(conn
);
891 rxrpc_activate_channels(next
);
893 /* We need to get rid of the temporary ref we took upon next, but we
894 * can't call rxrpc_put_connection() recursively.
900 * Clean up a dead client connections.
902 void rxrpc_put_client_conn(struct rxrpc_connection
*conn
)
904 const void *here
= __builtin_return_address(0);
908 n
= atomic_dec_return(&conn
->usage
);
909 trace_rxrpc_conn(conn
, rxrpc_conn_put_client
, n
, here
);
914 conn
= rxrpc_put_one_client_conn(conn
);
919 * Kill the longest-active client connections to make room for new ones.
921 static void rxrpc_cull_active_client_conns(void)
923 struct rxrpc_connection
*conn
;
924 unsigned int nr_conns
= rxrpc_nr_client_conns
;
925 unsigned int nr_active
, limit
;
929 ASSERTCMP(nr_conns
, >=, 0);
930 if (nr_conns
< rxrpc_max_client_connections
) {
934 limit
= rxrpc_reap_client_connections
;
936 spin_lock(&rxrpc_client_conn_cache_lock
);
937 nr_active
= rxrpc_nr_active_client_conns
;
939 while (nr_active
> limit
) {
940 ASSERT(!list_empty(&rxrpc_active_client_conns
));
941 conn
= list_entry(rxrpc_active_client_conns
.next
,
942 struct rxrpc_connection
, cache_link
);
943 ASSERTCMP(conn
->cache_state
, ==, RXRPC_CONN_CLIENT_ACTIVE
);
945 if (list_empty(&conn
->waiting_calls
)) {
946 trace_rxrpc_client(conn
, -1, rxrpc_client_to_culled
);
947 conn
->cache_state
= RXRPC_CONN_CLIENT_CULLED
;
948 list_del_init(&conn
->cache_link
);
950 trace_rxrpc_client(conn
, -1, rxrpc_client_to_waiting
);
951 conn
->cache_state
= RXRPC_CONN_CLIENT_WAITING
;
952 list_move_tail(&conn
->cache_link
,
953 &rxrpc_waiting_client_conns
);
959 rxrpc_nr_active_client_conns
= nr_active
;
960 spin_unlock(&rxrpc_client_conn_cache_lock
);
961 ASSERTCMP(nr_active
, >=, 0);
966 * Discard expired client connections from the idle list. Each conn in the
967 * idle list has been exposed and holds an extra ref because of that.
969 * This may be called from conn setup or from a work item so cannot be
970 * considered non-reentrant.
972 static void rxrpc_discard_expired_client_conns(struct work_struct
*work
)
974 struct rxrpc_connection
*conn
;
975 unsigned long expiry
, conn_expires_at
, now
;
976 unsigned int nr_conns
;
977 bool did_discard
= false;
979 _enter("%c", work
? 'w' : 'n');
981 if (list_empty(&rxrpc_idle_client_conns
)) {
986 /* Don't double up on the discarding */
987 if (!spin_trylock(&rxrpc_client_conn_discard_mutex
)) {
988 _leave(" [already]");
992 /* We keep an estimate of what the number of conns ought to be after
993 * we've discarded some so that we don't overdo the discarding.
995 nr_conns
= rxrpc_nr_client_conns
;
998 spin_lock(&rxrpc_client_conn_cache_lock
);
1000 if (list_empty(&rxrpc_idle_client_conns
))
1003 conn
= list_entry(rxrpc_idle_client_conns
.next
,
1004 struct rxrpc_connection
, cache_link
);
1005 ASSERT(test_bit(RXRPC_CONN_EXPOSED
, &conn
->flags
));
1007 if (!rxrpc_kill_all_client_conns
) {
1008 /* If the number of connections is over the reap limit, we
1009 * expedite discard by reducing the expiry timeout. We must,
1010 * however, have at least a short grace period to be able to do
1011 * final-ACK or ABORT retransmission.
1013 expiry
= rxrpc_conn_idle_client_expiry
;
1014 if (nr_conns
> rxrpc_reap_client_connections
)
1015 expiry
= rxrpc_conn_idle_client_fast_expiry
;
1017 conn_expires_at
= conn
->idle_timestamp
+ expiry
;
1019 now
= READ_ONCE(jiffies
);
1020 if (time_after(conn_expires_at
, now
))
1021 goto not_yet_expired
;
1024 trace_rxrpc_client(conn
, -1, rxrpc_client_discard
);
1025 if (!test_and_clear_bit(RXRPC_CONN_EXPOSED
, &conn
->flags
))
1027 conn
->cache_state
= RXRPC_CONN_CLIENT_INACTIVE
;
1028 list_del_init(&conn
->cache_link
);
1030 spin_unlock(&rxrpc_client_conn_cache_lock
);
1032 /* When we cleared the EXPOSED flag, we took on responsibility for the
1033 * reference that that had on the usage count. We deal with that here.
1034 * If someone re-sets the flag and re-gets the ref, that's fine.
1036 rxrpc_put_connection(conn
);
1042 /* The connection at the front of the queue hasn't yet expired, so
1043 * schedule the work item for that point if we discarded something.
1045 * We don't worry if the work item is already scheduled - it can look
1046 * after rescheduling itself at a later time. We could cancel it, but
1047 * then things get messier.
1050 if (!rxrpc_kill_all_client_conns
)
1051 queue_delayed_work(rxrpc_workqueue
,
1052 &rxrpc_client_conn_reap
,
1053 conn_expires_at
- now
);
1056 spin_unlock(&rxrpc_client_conn_cache_lock
);
1057 spin_unlock(&rxrpc_client_conn_discard_mutex
);
1062 * Preemptively destroy all the client connection records rather than waiting
1063 * for them to time out
1065 void __exit
rxrpc_destroy_all_client_connections(void)
1069 spin_lock(&rxrpc_client_conn_cache_lock
);
1070 rxrpc_kill_all_client_conns
= true;
1071 spin_unlock(&rxrpc_client_conn_cache_lock
);
1073 cancel_delayed_work(&rxrpc_client_conn_reap
);
1075 if (!queue_delayed_work(rxrpc_workqueue
, &rxrpc_client_conn_reap
, 0))
1076 _debug("destroy: queue failed");