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);
195 if (conn
->params
.exclusive
)
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 _leave(" = %p", conn
);
227 conn
->security
->clear(conn
);
229 rxrpc_put_client_connection_id(conn
);
232 _leave(" = %d", ret
);
237 * Determine if a connection may be reused.
239 static bool rxrpc_may_reuse_conn(struct rxrpc_connection
*conn
)
241 int id_cursor
, id
, distance
, limit
;
243 if (test_bit(RXRPC_CONN_DONT_REUSE
, &conn
->flags
))
246 if (conn
->proto
.epoch
!= rxrpc_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
= READ_ONCE(rxrpc_client_conn_ids
.cur
);
256 id
= conn
->proto
.cid
>> RXRPC_CIDSHIFT
;
257 distance
= id
- id_cursor
;
259 distance
= -distance
;
260 limit
= round_up(rxrpc_max_client_connections
, IDR_SIZE
) * 4;
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 /* If the connection is not meant to be exclusive, search the available
296 * connections to see if the connection we want to use already exists.
298 if (!cp
->exclusive
) {
300 spin_lock(&local
->client_conns_lock
);
301 p
= local
->client_conns
.rb_node
;
303 conn
= rb_entry(p
, struct rxrpc_connection
, client_node
);
305 #define cmp(X) ((long)conn->params.X - (long)cp->X)
308 cmp(security_level
));
312 } else if (diff
> 0) {
315 if (rxrpc_may_reuse_conn(conn
) &&
316 rxrpc_get_connection_maybe(conn
))
317 goto found_extant_conn
;
318 /* The connection needs replacing. It's better
319 * to effect that when we have something to
320 * replace it with so that we don't have to
321 * rebalance the tree twice.
326 spin_unlock(&local
->client_conns_lock
);
329 /* There wasn't a connection yet or we need an exclusive connection.
330 * We need to create a candidate and then potentially redo the search
331 * in case we're racing with another thread also trying to connect on a
332 * shareable connection.
335 candidate
= rxrpc_alloc_client_connection(cp
, gfp
);
336 if (IS_ERR(candidate
)) {
337 ret
= PTR_ERR(candidate
);
341 /* Add the call to the new connection's waiting list in case we're
342 * going to have to wait for the connection to come live. It's our
343 * connection, so we want first dibs on the channel slots. We would
344 * normally have to take channel_lock but we do this before anyone else
345 * can see the connection.
347 list_add_tail(&call
->chan_wait_link
, &candidate
->waiting_calls
);
350 call
->conn
= candidate
;
351 call
->security_ix
= candidate
->security_ix
;
352 _leave(" = 0 [exclusive %d]", candidate
->debug_id
);
356 /* Publish the new connection for userspace to find. We need to redo
357 * the search before doing this lest we race with someone else adding a
358 * conflicting instance.
361 spin_lock(&local
->client_conns_lock
);
363 pp
= &local
->client_conns
.rb_node
;
367 conn
= rb_entry(parent
, struct rxrpc_connection
, client_node
);
369 #define cmp(X) ((long)conn->params.X - (long)candidate->params.X)
372 cmp(security_level
));
375 pp
= &(*pp
)->rb_left
;
376 } else if (diff
> 0) {
377 pp
= &(*pp
)->rb_right
;
379 if (rxrpc_may_reuse_conn(conn
) &&
380 rxrpc_get_connection_maybe(conn
))
381 goto found_extant_conn
;
382 /* The old connection is from an outdated epoch. */
383 _debug("replace conn");
384 clear_bit(RXRPC_CONN_IN_CLIENT_CONNS
, &conn
->flags
);
385 rb_replace_node(&conn
->client_node
,
386 &candidate
->client_node
,
387 &local
->client_conns
);
388 goto candidate_published
;
393 rb_link_node(&candidate
->client_node
, parent
, pp
);
394 rb_insert_color(&candidate
->client_node
, &local
->client_conns
);
397 set_bit(RXRPC_CONN_IN_CLIENT_CONNS
, &candidate
->flags
);
398 call
->conn
= candidate
;
399 call
->security_ix
= candidate
->security_ix
;
400 spin_unlock(&local
->client_conns_lock
);
401 _leave(" = 0 [new %d]", candidate
->debug_id
);
404 /* We come here if we found a suitable connection already in existence.
405 * Discard any candidate we may have allocated, and try to get a
406 * channel on this one.
409 _debug("found conn");
410 spin_unlock(&local
->client_conns_lock
);
412 rxrpc_put_connection(candidate
);
415 spin_lock(&conn
->channel_lock
);
417 call
->security_ix
= conn
->security_ix
;
418 list_add(&call
->chan_wait_link
, &conn
->waiting_calls
);
419 spin_unlock(&conn
->channel_lock
);
420 _leave(" = 0 [extant %d]", conn
->debug_id
);
424 rxrpc_put_peer(cp
->peer
);
427 _leave(" = %d", ret
);
432 * Activate a connection.
434 static void rxrpc_activate_conn(struct rxrpc_connection
*conn
)
436 conn
->cache_state
= RXRPC_CONN_CLIENT_ACTIVE
;
437 rxrpc_nr_active_client_conns
++;
438 list_move_tail(&conn
->cache_link
, &rxrpc_active_client_conns
);
442 * Attempt to animate a connection for a new call.
444 * If it's not exclusive, the connection is in the endpoint tree, and we're in
445 * the conn's list of those waiting to grab a channel. There is, however, a
446 * limit on the number of live connections allowed at any one time, so we may
447 * have to wait for capacity to become available.
449 * Note that a connection on the waiting queue might *also* have active
450 * channels if it has been culled to make space and then re-requested by a new
453 static void rxrpc_animate_client_conn(struct rxrpc_connection
*conn
)
455 unsigned int nr_conns
;
457 _enter("%d,%d", conn
->debug_id
, conn
->cache_state
);
459 if (conn
->cache_state
== RXRPC_CONN_CLIENT_ACTIVE
)
462 spin_lock(&rxrpc_client_conn_cache_lock
);
464 nr_conns
= rxrpc_nr_client_conns
;
465 if (!test_and_set_bit(RXRPC_CONN_COUNTED
, &conn
->flags
))
466 rxrpc_nr_client_conns
= nr_conns
+ 1;
468 switch (conn
->cache_state
) {
469 case RXRPC_CONN_CLIENT_ACTIVE
:
470 case RXRPC_CONN_CLIENT_WAITING
:
473 case RXRPC_CONN_CLIENT_INACTIVE
:
474 case RXRPC_CONN_CLIENT_CULLED
:
475 case RXRPC_CONN_CLIENT_IDLE
:
476 if (nr_conns
>= rxrpc_max_client_connections
)
477 goto wait_for_capacity
;
485 spin_unlock(&rxrpc_client_conn_cache_lock
);
487 _leave(" [%d]", conn
->cache_state
);
492 rxrpc_activate_conn(conn
);
497 conn
->cache_state
= RXRPC_CONN_CLIENT_WAITING
;
498 list_move_tail(&conn
->cache_link
, &rxrpc_waiting_client_conns
);
503 * Deactivate a channel.
505 static void rxrpc_deactivate_one_channel(struct rxrpc_connection
*conn
,
506 unsigned int channel
)
508 struct rxrpc_channel
*chan
= &conn
->channels
[channel
];
510 rcu_assign_pointer(chan
->call
, NULL
);
511 conn
->active_chans
&= ~(1 << channel
);
515 * Assign a channel to the call at the front of the queue and wake the call up.
516 * We don't increment the callNumber counter until this number has been exposed
519 static void rxrpc_activate_one_channel(struct rxrpc_connection
*conn
,
520 unsigned int channel
)
522 struct rxrpc_channel
*chan
= &conn
->channels
[channel
];
523 struct rxrpc_call
*call
= list_entry(conn
->waiting_calls
.next
,
524 struct rxrpc_call
, chan_wait_link
);
525 u32 call_id
= chan
->call_counter
+ 1;
527 write_lock_bh(&call
->state_lock
);
528 call
->state
= RXRPC_CALL_CLIENT_SEND_REQUEST
;
529 write_unlock_bh(&call
->state_lock
);
531 rxrpc_see_call(call
);
532 list_del_init(&call
->chan_wait_link
);
533 conn
->active_chans
|= 1 << channel
;
534 call
->peer
= rxrpc_get_peer(conn
->params
.peer
);
535 call
->cid
= conn
->proto
.cid
| channel
;
536 call
->call_id
= call_id
;
538 _net("CONNECT call %08x:%08x as call %d on conn %d",
539 call
->cid
, call
->call_id
, call
->debug_id
, conn
->debug_id
);
541 /* Paired with the read barrier in rxrpc_wait_for_channel(). This
542 * orders cid and epoch in the connection wrt to call_id without the
543 * need to take the channel_lock.
545 * We provisionally assign a callNumber at this point, but we don't
546 * confirm it until the call is about to be exposed.
548 * TODO: Pair with a barrier in the data_ready handler when that looks
549 * at the call ID through a connection channel.
552 chan
->call_id
= call_id
;
553 rcu_assign_pointer(chan
->call
, call
);
554 wake_up(&call
->waitq
);
558 * Assign channels and callNumbers to waiting calls.
560 static void rxrpc_activate_channels(struct rxrpc_connection
*conn
)
564 _enter("%d", conn
->debug_id
);
566 if (conn
->cache_state
!= RXRPC_CONN_CLIENT_ACTIVE
||
567 conn
->active_chans
== RXRPC_ACTIVE_CHANS_MASK
)
570 spin_lock(&conn
->channel_lock
);
572 while (!list_empty(&conn
->waiting_calls
) &&
573 (mask
= ~conn
->active_chans
,
574 mask
&= RXRPC_ACTIVE_CHANS_MASK
,
576 rxrpc_activate_one_channel(conn
, __ffs(mask
));
578 spin_unlock(&conn
->channel_lock
);
583 * Wait for a callNumber and a channel to be granted to a call.
585 static int rxrpc_wait_for_channel(struct rxrpc_call
*call
, gfp_t gfp
)
589 _enter("%d", call
->debug_id
);
591 if (!call
->call_id
) {
592 DECLARE_WAITQUEUE(myself
, current
);
594 if (!gfpflags_allow_blocking(gfp
)) {
599 add_wait_queue_exclusive(&call
->waitq
, &myself
);
601 set_current_state(TASK_INTERRUPTIBLE
);
604 if (signal_pending(current
)) {
610 remove_wait_queue(&call
->waitq
, &myself
);
611 __set_current_state(TASK_RUNNING
);
614 /* Paired with the write barrier in rxrpc_activate_one_channel(). */
618 _leave(" = %d", ret
);
623 * find a connection for a call
624 * - called in process context with IRQs enabled
626 int rxrpc_connect_call(struct rxrpc_call
*call
,
627 struct rxrpc_conn_parameters
*cp
,
628 struct sockaddr_rxrpc
*srx
,
633 _enter("{%d,%lx},", call
->debug_id
, call
->user_call_ID
);
635 rxrpc_discard_expired_client_conns(NULL
);
636 rxrpc_cull_active_client_conns();
638 ret
= rxrpc_get_client_conn(call
, cp
, srx
, gfp
);
642 rxrpc_animate_client_conn(call
->conn
);
643 rxrpc_activate_channels(call
->conn
);
645 ret
= rxrpc_wait_for_channel(call
, gfp
);
647 rxrpc_disconnect_client_call(call
);
649 _leave(" = %d", ret
);
654 * Note that a connection is about to be exposed to the world. Once it is
655 * exposed, we maintain an extra ref on it that stops it from being summarily
656 * discarded before it's (a) had a chance to deal with retransmission and (b)
657 * had a chance at re-use (the per-connection security negotiation is
660 static void rxrpc_expose_client_conn(struct rxrpc_connection
*conn
)
662 if (!test_and_set_bit(RXRPC_CONN_EXPOSED
, &conn
->flags
))
663 rxrpc_get_connection(conn
);
667 * Note that a call, and thus a connection, is about to be exposed to the
670 void rxrpc_expose_client_call(struct rxrpc_call
*call
)
672 struct rxrpc_connection
*conn
= call
->conn
;
673 struct rxrpc_channel
*chan
=
674 &conn
->channels
[call
->cid
& RXRPC_CHANNELMASK
];
676 if (!test_and_set_bit(RXRPC_CALL_EXPOSED
, &call
->flags
)) {
677 /* Mark the call ID as being used. If the callNumber counter
678 * exceeds ~2 billion, we kill the connection after its
679 * outstanding calls have finished so that the counter doesn't
682 chan
->call_counter
++;
683 if (chan
->call_counter
>= INT_MAX
)
684 set_bit(RXRPC_CONN_DONT_REUSE
, &conn
->flags
);
685 rxrpc_expose_client_conn(conn
);
690 * Disconnect a client call.
692 void rxrpc_disconnect_client_call(struct rxrpc_call
*call
)
694 unsigned int channel
= call
->cid
& RXRPC_CHANNELMASK
;
695 struct rxrpc_connection
*conn
= call
->conn
;
696 struct rxrpc_channel
*chan
= &conn
->channels
[channel
];
700 spin_lock(&conn
->channel_lock
);
702 /* Calls that have never actually been assigned a channel can simply be
703 * discarded. If the conn didn't get used either, it will follow
704 * immediately unless someone else grabs it in the meantime.
706 if (!list_empty(&call
->chan_wait_link
)) {
707 _debug("call is waiting");
708 ASSERTCMP(call
->call_id
, ==, 0);
709 ASSERT(!test_bit(RXRPC_CALL_EXPOSED
, &call
->flags
));
710 list_del_init(&call
->chan_wait_link
);
712 /* We must deactivate or idle the connection if it's now
713 * waiting for nothing.
715 spin_lock(&rxrpc_client_conn_cache_lock
);
716 if (conn
->cache_state
== RXRPC_CONN_CLIENT_WAITING
&&
717 list_empty(&conn
->waiting_calls
) &&
719 goto idle_connection
;
723 ASSERTCMP(rcu_access_pointer(chan
->call
), ==, call
);
724 ASSERTCMP(atomic_read(&conn
->usage
), >=, 2);
726 /* If a client call was exposed to the world, we save the result for
729 * We use a barrier here so that the call number and abort code can be
730 * read without needing to take a lock.
732 * TODO: Make the incoming packet handler check this and handle
733 * terminal retransmission without requiring access to the call.
735 if (test_bit(RXRPC_CALL_EXPOSED
, &call
->flags
)) {
736 _debug("exposed %u,%u", call
->call_id
, call
->abort_code
);
737 __rxrpc_disconnect_call(conn
, call
);
740 /* See if we can pass the channel directly to another call. */
741 if (conn
->cache_state
== RXRPC_CONN_CLIENT_ACTIVE
&&
742 !list_empty(&conn
->waiting_calls
)) {
744 rxrpc_activate_one_channel(conn
, channel
);
748 /* Things are more complex and we need the cache lock. We might be
749 * able to simply idle the conn or it might now be lurking on the wait
750 * list. It might even get moved back to the active list whilst we're
751 * waiting for the lock.
753 spin_lock(&rxrpc_client_conn_cache_lock
);
755 switch (conn
->cache_state
) {
756 case RXRPC_CONN_CLIENT_ACTIVE
:
757 if (list_empty(&conn
->waiting_calls
)) {
758 rxrpc_deactivate_one_channel(conn
, channel
);
759 if (!conn
->active_chans
) {
760 rxrpc_nr_active_client_conns
--;
761 goto idle_connection
;
766 _debug("pass chan 2");
767 rxrpc_activate_one_channel(conn
, channel
);
770 case RXRPC_CONN_CLIENT_CULLED
:
771 rxrpc_deactivate_one_channel(conn
, channel
);
772 ASSERT(list_empty(&conn
->waiting_calls
));
773 if (!conn
->active_chans
)
774 goto idle_connection
;
777 case RXRPC_CONN_CLIENT_WAITING
:
778 rxrpc_deactivate_one_channel(conn
, channel
);
786 spin_unlock(&rxrpc_client_conn_cache_lock
);
788 spin_unlock(&conn
->channel_lock
);
789 rxrpc_put_connection(conn
);
794 /* As no channels remain active, the connection gets deactivated
795 * immediately or moved to the idle list for a short while.
797 if (test_bit(RXRPC_CONN_EXPOSED
, &conn
->flags
)) {
799 conn
->idle_timestamp
= jiffies
;
800 conn
->cache_state
= RXRPC_CONN_CLIENT_IDLE
;
801 list_move_tail(&conn
->cache_link
, &rxrpc_idle_client_conns
);
802 if (rxrpc_idle_client_conns
.next
== &conn
->cache_link
&&
803 !rxrpc_kill_all_client_conns
)
804 queue_delayed_work(rxrpc_workqueue
,
805 &rxrpc_client_conn_reap
,
806 rxrpc_conn_idle_client_expiry
);
808 _debug("make inactive");
809 conn
->cache_state
= RXRPC_CONN_CLIENT_INACTIVE
;
810 list_del_init(&conn
->cache_link
);
816 * Clean up a dead client connection.
818 static struct rxrpc_connection
*
819 rxrpc_put_one_client_conn(struct rxrpc_connection
*conn
)
821 struct rxrpc_connection
*next
;
822 struct rxrpc_local
*local
= conn
->params
.local
;
823 unsigned int nr_conns
;
825 if (test_bit(RXRPC_CONN_IN_CLIENT_CONNS
, &conn
->flags
)) {
826 spin_lock(&local
->client_conns_lock
);
827 if (test_and_clear_bit(RXRPC_CONN_IN_CLIENT_CONNS
,
829 rb_erase(&conn
->client_node
, &local
->client_conns
);
830 spin_unlock(&local
->client_conns_lock
);
833 rxrpc_put_client_connection_id(conn
);
835 ASSERTCMP(conn
->cache_state
, ==, RXRPC_CONN_CLIENT_INACTIVE
);
837 if (!test_bit(RXRPC_CONN_COUNTED
, &conn
->flags
))
840 spin_lock(&rxrpc_client_conn_cache_lock
);
841 nr_conns
= --rxrpc_nr_client_conns
;
844 if (nr_conns
< rxrpc_max_client_connections
&&
845 !list_empty(&rxrpc_waiting_client_conns
)) {
846 next
= list_entry(rxrpc_waiting_client_conns
.next
,
847 struct rxrpc_connection
, cache_link
);
848 rxrpc_get_connection(next
);
849 rxrpc_activate_conn(next
);
852 spin_unlock(&rxrpc_client_conn_cache_lock
);
853 rxrpc_kill_connection(conn
);
856 rxrpc_activate_channels(next
);
858 /* We need to get rid of the temporary ref we took upon next, but we
859 * can't call rxrpc_put_connection() recursively.
865 * Clean up a dead client connections.
867 void rxrpc_put_client_conn(struct rxrpc_connection
*conn
)
869 struct rxrpc_connection
*next
;
872 _enter("%p{u=%d,d=%d}",
873 conn
, atomic_read(&conn
->usage
), conn
->debug_id
);
875 next
= rxrpc_put_one_client_conn(conn
);
880 } while (atomic_dec_and_test(&conn
->usage
));
886 * Kill the longest-active client connections to make room for new ones.
888 static void rxrpc_cull_active_client_conns(void)
890 struct rxrpc_connection
*conn
;
891 unsigned int nr_conns
= rxrpc_nr_client_conns
;
892 unsigned int nr_active
, limit
;
896 ASSERTCMP(nr_conns
, >=, 0);
897 if (nr_conns
< rxrpc_max_client_connections
) {
901 limit
= rxrpc_reap_client_connections
;
903 spin_lock(&rxrpc_client_conn_cache_lock
);
904 nr_active
= rxrpc_nr_active_client_conns
;
906 while (nr_active
> limit
) {
907 ASSERT(!list_empty(&rxrpc_active_client_conns
));
908 conn
= list_entry(rxrpc_active_client_conns
.next
,
909 struct rxrpc_connection
, cache_link
);
910 ASSERTCMP(conn
->cache_state
, ==, RXRPC_CONN_CLIENT_ACTIVE
);
912 if (list_empty(&conn
->waiting_calls
)) {
913 conn
->cache_state
= RXRPC_CONN_CLIENT_CULLED
;
914 list_del_init(&conn
->cache_link
);
916 conn
->cache_state
= RXRPC_CONN_CLIENT_WAITING
;
917 list_move_tail(&conn
->cache_link
,
918 &rxrpc_waiting_client_conns
);
924 rxrpc_nr_active_client_conns
= nr_active
;
925 spin_unlock(&rxrpc_client_conn_cache_lock
);
926 ASSERTCMP(nr_active
, >=, 0);
931 * Discard expired client connections from the idle list. Each conn in the
932 * idle list has been exposed and holds an extra ref because of that.
934 * This may be called from conn setup or from a work item so cannot be
935 * considered non-reentrant.
937 static void rxrpc_discard_expired_client_conns(struct work_struct
*work
)
939 struct rxrpc_connection
*conn
;
940 unsigned long expiry
, conn_expires_at
, now
;
941 unsigned int nr_conns
;
942 bool did_discard
= false;
944 _enter("%c", work
? 'w' : 'n');
946 if (list_empty(&rxrpc_idle_client_conns
)) {
951 /* Don't double up on the discarding */
952 if (!spin_trylock(&rxrpc_client_conn_discard_mutex
)) {
953 _leave(" [already]");
957 /* We keep an estimate of what the number of conns ought to be after
958 * we've discarded some so that we don't overdo the discarding.
960 nr_conns
= rxrpc_nr_client_conns
;
963 spin_lock(&rxrpc_client_conn_cache_lock
);
965 if (list_empty(&rxrpc_idle_client_conns
))
968 conn
= list_entry(rxrpc_idle_client_conns
.next
,
969 struct rxrpc_connection
, cache_link
);
970 ASSERT(test_bit(RXRPC_CONN_EXPOSED
, &conn
->flags
));
972 if (!rxrpc_kill_all_client_conns
) {
973 /* If the number of connections is over the reap limit, we
974 * expedite discard by reducing the expiry timeout. We must,
975 * however, have at least a short grace period to be able to do
976 * final-ACK or ABORT retransmission.
978 expiry
= rxrpc_conn_idle_client_expiry
;
979 if (nr_conns
> rxrpc_reap_client_connections
)
980 expiry
= rxrpc_conn_idle_client_fast_expiry
;
982 conn_expires_at
= conn
->idle_timestamp
+ expiry
;
984 now
= READ_ONCE(jiffies
);
985 if (time_after(conn_expires_at
, now
))
986 goto not_yet_expired
;
989 _debug("discard conn %d", conn
->debug_id
);
990 if (!test_and_clear_bit(RXRPC_CONN_EXPOSED
, &conn
->flags
))
992 conn
->cache_state
= RXRPC_CONN_CLIENT_INACTIVE
;
993 list_del_init(&conn
->cache_link
);
995 spin_unlock(&rxrpc_client_conn_cache_lock
);
997 /* When we cleared the EXPOSED flag, we took on responsibility for the
998 * reference that that had on the usage count. We deal with that here.
999 * If someone re-sets the flag and re-gets the ref, that's fine.
1001 rxrpc_put_connection(conn
);
1007 /* The connection at the front of the queue hasn't yet expired, so
1008 * schedule the work item for that point if we discarded something.
1010 * We don't worry if the work item is already scheduled - it can look
1011 * after rescheduling itself at a later time. We could cancel it, but
1012 * then things get messier.
1015 if (!rxrpc_kill_all_client_conns
)
1016 queue_delayed_work(rxrpc_workqueue
,
1017 &rxrpc_client_conn_reap
,
1018 conn_expires_at
- now
);
1021 spin_unlock(&rxrpc_client_conn_cache_lock
);
1022 spin_unlock(&rxrpc_client_conn_discard_mutex
);
1027 * Preemptively destroy all the client connection records rather than waiting
1028 * for them to time out
1030 void __exit
rxrpc_destroy_all_client_connections(void)
1034 spin_lock(&rxrpc_client_conn_cache_lock
);
1035 rxrpc_kill_all_client_conns
= true;
1036 spin_unlock(&rxrpc_client_conn_cache_lock
);
1038 cancel_delayed_work(&rxrpc_client_conn_reap
);
1040 if (!queue_delayed_work(rxrpc_workqueue
, &rxrpc_client_conn_reap
, 0))
1041 _debug("destroy: queue failed");