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4a3388c8 DH |
1 | /* Client connection-specific management code. |
2 | * | |
3 | * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
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. | |
45025bce DH |
10 | * |
11 | * | |
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. | |
15 | * | |
16 | * Client connections can be in one of a number of cache states: | |
17 | * | |
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. | |
21 | * | |
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. | |
25 | * | |
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. | |
29 | * | |
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. | |
33 | * | |
34 | * The connection is on the rxrpc_active_client_conns list which is kept | |
35 | * in activation order for culling purposes. | |
36 | * | |
37 | * rxrpc_nr_active_client_conns is held incremented also. | |
38 | * | |
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. | |
43 | * | |
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 | |
47 | * the INACTIVE state. | |
48 | * | |
49 | * The connection is on the rxrpc_idle_client_conns list which is kept in | |
50 | * order of how soon they'll expire. | |
51 | * | |
52 | * There are flags of relevance to the cache: | |
53 | * | |
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. | |
58 | * | |
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. | |
62 | * | |
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. | |
66 | * | |
67 | * The caching state may only be changed if the cache lock is held. | |
68 | * | |
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. | |
4a3388c8 DH |
72 | */ |
73 | ||
74 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
75 | ||
76 | #include <linux/slab.h> | |
77 | #include <linux/idr.h> | |
78 | #include <linux/timer.h> | |
174cd4b1 IM |
79 | #include <linux/sched/signal.h> |
80 | ||
4a3388c8 DH |
81 | #include "ar-internal.h" |
82 | ||
45025bce DH |
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; | |
87 | ||
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; | |
91 | ||
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); | |
97 | ||
4a3388c8 DH |
98 | /* |
99 | * We use machine-unique IDs for our client connections. | |
100 | */ | |
101 | DEFINE_IDR(rxrpc_client_conn_ids); | |
102 | static DEFINE_SPINLOCK(rxrpc_conn_id_lock); | |
103 | ||
45025bce DH |
104 | static void rxrpc_cull_active_client_conns(void); |
105 | static void rxrpc_discard_expired_client_conns(struct work_struct *); | |
106 | ||
107 | static DECLARE_DELAYED_WORK(rxrpc_client_conn_reap, | |
108 | rxrpc_discard_expired_client_conns); | |
109 | ||
4a3388c8 DH |
110 | /* |
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 | |
090f85de DH |
113 | * epoch doesn't change until the client is rebooted (or, at least, unless the |
114 | * module is unloaded). | |
4a3388c8 | 115 | */ |
c6d2b8d7 DH |
116 | static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn, |
117 | gfp_t gfp) | |
4a3388c8 | 118 | { |
4a3388c8 DH |
119 | int id; |
120 | ||
121 | _enter(""); | |
122 | ||
123 | idr_preload(gfp); | |
4a3388c8 DH |
124 | spin_lock(&rxrpc_conn_id_lock); |
125 | ||
090f85de DH |
126 | id = idr_alloc_cyclic(&rxrpc_client_conn_ids, conn, |
127 | 1, 0x40000000, GFP_NOWAIT); | |
128 | if (id < 0) | |
129 | goto error; | |
4a3388c8 DH |
130 | |
131 | spin_unlock(&rxrpc_conn_id_lock); | |
4a3388c8 DH |
132 | idr_preload_end(); |
133 | ||
090f85de | 134 | conn->proto.epoch = rxrpc_epoch; |
4a3388c8 DH |
135 | conn->proto.cid = id << RXRPC_CIDSHIFT; |
136 | set_bit(RXRPC_CONN_HAS_IDR, &conn->flags); | |
090f85de | 137 | _leave(" [CID %x]", conn->proto.cid); |
4a3388c8 DH |
138 | return 0; |
139 | ||
140 | error: | |
141 | spin_unlock(&rxrpc_conn_id_lock); | |
4a3388c8 DH |
142 | idr_preload_end(); |
143 | _leave(" = %d", id); | |
144 | return id; | |
145 | } | |
146 | ||
147 | /* | |
148 | * Release a connection ID for a client connection from the global pool. | |
149 | */ | |
001c1122 | 150 | static void rxrpc_put_client_connection_id(struct rxrpc_connection *conn) |
4a3388c8 DH |
151 | { |
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); | |
157 | } | |
158 | } | |
eb9b9d22 DH |
159 | |
160 | /* | |
161 | * Destroy the client connection ID tree. | |
162 | */ | |
163 | void rxrpc_destroy_client_conn_ids(void) | |
164 | { | |
165 | struct rxrpc_connection *conn; | |
166 | int id; | |
167 | ||
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)); | |
172 | } | |
173 | BUG(); | |
174 | } | |
175 | ||
176 | idr_destroy(&rxrpc_client_conn_ids); | |
177 | } | |
c6d2b8d7 DH |
178 | |
179 | /* | |
45025bce | 180 | * Allocate a client connection. |
c6d2b8d7 DH |
181 | */ |
182 | static struct rxrpc_connection * | |
183 | rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp) | |
184 | { | |
185 | struct rxrpc_connection *conn; | |
186 | int ret; | |
187 | ||
188 | _enter(""); | |
189 | ||
190 | conn = rxrpc_alloc_connection(gfp); | |
191 | if (!conn) { | |
192 | _leave(" = -ENOMEM"); | |
193 | return ERR_PTR(-ENOMEM); | |
194 | } | |
195 | ||
45025bce | 196 | atomic_set(&conn->usage, 1); |
8732db67 | 197 | if (cp->exclusive) |
45025bce DH |
198 | __set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags); |
199 | ||
c6d2b8d7 | 200 | conn->params = *cp; |
c6d2b8d7 DH |
201 | conn->out_clientflag = RXRPC_CLIENT_INITIATED; |
202 | conn->state = RXRPC_CONN_CLIENT; | |
203 | ||
c6d2b8d7 DH |
204 | ret = rxrpc_get_client_connection_id(conn, gfp); |
205 | if (ret < 0) | |
206 | goto error_0; | |
207 | ||
208 | ret = rxrpc_init_client_conn_security(conn); | |
209 | if (ret < 0) | |
210 | goto error_1; | |
211 | ||
212 | ret = conn->security->prime_packet_security(conn); | |
213 | if (ret < 0) | |
214 | goto error_2; | |
215 | ||
216 | write_lock(&rxrpc_connection_lock); | |
4d028b2c | 217 | list_add_tail(&conn->proc_link, &rxrpc_connection_proc_list); |
c6d2b8d7 DH |
218 | write_unlock(&rxrpc_connection_lock); |
219 | ||
220 | /* We steal the caller's peer ref. */ | |
221 | cp->peer = NULL; | |
222 | rxrpc_get_local(conn->params.local); | |
223 | key_get(conn->params.key); | |
224 | ||
363deeab DH |
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); | |
c6d2b8d7 DH |
228 | _leave(" = %p", conn); |
229 | return conn; | |
230 | ||
231 | error_2: | |
232 | conn->security->clear(conn); | |
233 | error_1: | |
234 | rxrpc_put_client_connection_id(conn); | |
235 | error_0: | |
236 | kfree(conn); | |
237 | _leave(" = %d", ret); | |
238 | return ERR_PTR(ret); | |
239 | } | |
240 | ||
241 | /* | |
45025bce | 242 | * Determine if a connection may be reused. |
c6d2b8d7 | 243 | */ |
45025bce DH |
244 | static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn) |
245 | { | |
246 | int id_cursor, id, distance, limit; | |
247 | ||
248 | if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags)) | |
249 | goto dont_reuse; | |
250 | ||
251 | if (conn->proto.epoch != rxrpc_epoch) | |
252 | goto mark_dont_reuse; | |
253 | ||
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. | |
259 | */ | |
44430612 | 260 | id_cursor = idr_get_cursor(&rxrpc_client_conn_ids); |
45025bce DH |
261 | id = conn->proto.cid >> RXRPC_CIDSHIFT; |
262 | distance = id - id_cursor; | |
263 | if (distance < 0) | |
264 | distance = -distance; | |
44430612 | 265 | limit = max(rxrpc_max_client_connections * 4, 1024U); |
45025bce DH |
266 | if (distance > limit) |
267 | goto mark_dont_reuse; | |
268 | ||
269 | return true; | |
270 | ||
271 | mark_dont_reuse: | |
272 | set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags); | |
273 | dont_reuse: | |
274 | return false; | |
275 | } | |
276 | ||
277 | /* | |
278 | * Create or find a client connection to use for a call. | |
279 | * | |
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. | |
282 | */ | |
283 | static int rxrpc_get_client_conn(struct rxrpc_call *call, | |
284 | struct rxrpc_conn_parameters *cp, | |
285 | struct sockaddr_rxrpc *srx, | |
286 | gfp_t gfp) | |
c6d2b8d7 DH |
287 | { |
288 | struct rxrpc_connection *conn, *candidate = NULL; | |
289 | struct rxrpc_local *local = cp->local; | |
290 | struct rb_node *p, **pp, *parent; | |
291 | long diff; | |
45025bce | 292 | int ret = -ENOMEM; |
c6d2b8d7 DH |
293 | |
294 | _enter("{%d,%lx},", call->debug_id, call->user_call_ID); | |
295 | ||
296 | cp->peer = rxrpc_lookup_peer(cp->local, srx, gfp); | |
297 | if (!cp->peer) | |
45025bce | 298 | goto error; |
c6d2b8d7 | 299 | |
45025bce DH |
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. | |
302 | */ | |
c6d2b8d7 | 303 | if (!cp->exclusive) { |
c6d2b8d7 DH |
304 | _debug("search 1"); |
305 | spin_lock(&local->client_conns_lock); | |
306 | p = local->client_conns.rb_node; | |
307 | while (p) { | |
308 | conn = rb_entry(p, struct rxrpc_connection, client_node); | |
309 | ||
310 | #define cmp(X) ((long)conn->params.X - (long)cp->X) | |
311 | diff = (cmp(peer) ?: | |
312 | cmp(key) ?: | |
313 | cmp(security_level)); | |
45025bce DH |
314 | #undef cmp |
315 | if (diff < 0) { | |
c6d2b8d7 | 316 | p = p->rb_left; |
45025bce | 317 | } else if (diff > 0) { |
c6d2b8d7 | 318 | p = p->rb_right; |
45025bce DH |
319 | } else { |
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. | |
327 | */ | |
328 | break; | |
329 | } | |
c6d2b8d7 DH |
330 | } |
331 | spin_unlock(&local->client_conns_lock); | |
332 | } | |
333 | ||
45025bce DH |
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. | |
338 | */ | |
339 | _debug("new conn"); | |
c6d2b8d7 | 340 | candidate = rxrpc_alloc_client_connection(cp, gfp); |
45025bce DH |
341 | if (IS_ERR(candidate)) { |
342 | ret = PTR_ERR(candidate); | |
343 | goto error_peer; | |
c6d2b8d7 DH |
344 | } |
345 | ||
45025bce DH |
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. | |
351 | */ | |
352 | list_add_tail(&call->chan_wait_link, &candidate->waiting_calls); | |
353 | ||
c6d2b8d7 | 354 | if (cp->exclusive) { |
45025bce | 355 | call->conn = candidate; |
278ac0cd | 356 | call->security_ix = candidate->security_ix; |
45025bce DH |
357 | _leave(" = 0 [exclusive %d]", candidate->debug_id); |
358 | return 0; | |
c6d2b8d7 DH |
359 | } |
360 | ||
45025bce DH |
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. | |
c6d2b8d7 DH |
364 | */ |
365 | _debug("search 2"); | |
366 | spin_lock(&local->client_conns_lock); | |
367 | ||
368 | pp = &local->client_conns.rb_node; | |
369 | parent = NULL; | |
370 | while (*pp) { | |
371 | parent = *pp; | |
372 | conn = rb_entry(parent, struct rxrpc_connection, client_node); | |
373 | ||
45025bce | 374 | #define cmp(X) ((long)conn->params.X - (long)candidate->params.X) |
c6d2b8d7 DH |
375 | diff = (cmp(peer) ?: |
376 | cmp(key) ?: | |
377 | cmp(security_level)); | |
45025bce DH |
378 | #undef cmp |
379 | if (diff < 0) { | |
c6d2b8d7 | 380 | pp = &(*pp)->rb_left; |
45025bce | 381 | } else if (diff > 0) { |
c6d2b8d7 | 382 | pp = &(*pp)->rb_right; |
45025bce DH |
383 | } else { |
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); | |
363deeab | 393 | trace_rxrpc_client(conn, -1, rxrpc_client_replace); |
45025bce DH |
394 | goto candidate_published; |
395 | } | |
c6d2b8d7 DH |
396 | } |
397 | ||
c6d2b8d7 | 398 | _debug("new conn"); |
001c1122 DH |
399 | rb_link_node(&candidate->client_node, parent, pp); |
400 | rb_insert_color(&candidate->client_node, &local->client_conns); | |
c6d2b8d7 | 401 | |
45025bce DH |
402 | candidate_published: |
403 | set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags); | |
404 | call->conn = candidate; | |
278ac0cd | 405 | call->security_ix = candidate->security_ix; |
c6d2b8d7 | 406 | spin_unlock(&local->client_conns_lock); |
45025bce DH |
407 | _leave(" = 0 [new %d]", candidate->debug_id); |
408 | return 0; | |
c6d2b8d7 | 409 | |
45025bce DH |
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. | |
413 | */ | |
414 | found_extant_conn: | |
415 | _debug("found conn"); | |
416 | spin_unlock(&local->client_conns_lock); | |
c6d2b8d7 | 417 | |
363deeab DH |
418 | if (candidate) { |
419 | trace_rxrpc_client(candidate, -1, rxrpc_client_duplicate); | |
420 | rxrpc_put_connection(candidate); | |
421 | candidate = NULL; | |
422 | } | |
c6d2b8d7 | 423 | |
45025bce DH |
424 | spin_lock(&conn->channel_lock); |
425 | call->conn = conn; | |
278ac0cd | 426 | call->security_ix = conn->security_ix; |
45025bce | 427 | list_add(&call->chan_wait_link, &conn->waiting_calls); |
c6d2b8d7 | 428 | spin_unlock(&conn->channel_lock); |
45025bce DH |
429 | _leave(" = 0 [extant %d]", conn->debug_id); |
430 | return 0; | |
431 | ||
432 | error_peer: | |
c6d2b8d7 DH |
433 | rxrpc_put_peer(cp->peer); |
434 | cp->peer = NULL; | |
45025bce DH |
435 | error: |
436 | _leave(" = %d", ret); | |
437 | return ret; | |
438 | } | |
c6d2b8d7 | 439 | |
45025bce DH |
440 | /* |
441 | * Activate a connection. | |
442 | */ | |
443 | static void rxrpc_activate_conn(struct rxrpc_connection *conn) | |
444 | { | |
363deeab | 445 | trace_rxrpc_client(conn, -1, rxrpc_client_to_active); |
45025bce DH |
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); | |
449 | } | |
450 | ||
451 | /* | |
452 | * Attempt to animate a connection for a new call. | |
453 | * | |
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. | |
458 | * | |
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 | |
461 | * call. | |
462 | */ | |
463 | static void rxrpc_animate_client_conn(struct rxrpc_connection *conn) | |
464 | { | |
465 | unsigned int nr_conns; | |
466 | ||
467 | _enter("%d,%d", conn->debug_id, conn->cache_state); | |
468 | ||
469 | if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE) | |
470 | goto out; | |
471 | ||
472 | spin_lock(&rxrpc_client_conn_cache_lock); | |
473 | ||
474 | nr_conns = rxrpc_nr_client_conns; | |
363deeab DH |
475 | if (!test_and_set_bit(RXRPC_CONN_COUNTED, &conn->flags)) { |
476 | trace_rxrpc_client(conn, -1, rxrpc_client_count); | |
45025bce | 477 | rxrpc_nr_client_conns = nr_conns + 1; |
363deeab | 478 | } |
45025bce DH |
479 | |
480 | switch (conn->cache_state) { | |
481 | case RXRPC_CONN_CLIENT_ACTIVE: | |
482 | case RXRPC_CONN_CLIENT_WAITING: | |
483 | break; | |
484 | ||
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; | |
490 | goto activate_conn; | |
491 | ||
492 | default: | |
493 | BUG(); | |
001c1122 DH |
494 | } |
495 | ||
45025bce DH |
496 | out_unlock: |
497 | spin_unlock(&rxrpc_client_conn_cache_lock); | |
498 | out: | |
499 | _leave(" [%d]", conn->cache_state); | |
500 | return; | |
c6d2b8d7 | 501 | |
45025bce DH |
502 | activate_conn: |
503 | _debug("activate"); | |
504 | rxrpc_activate_conn(conn); | |
505 | goto out_unlock; | |
506 | ||
507 | wait_for_capacity: | |
508 | _debug("wait"); | |
363deeab | 509 | trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting); |
45025bce DH |
510 | conn->cache_state = RXRPC_CONN_CLIENT_WAITING; |
511 | list_move_tail(&conn->cache_link, &rxrpc_waiting_client_conns); | |
512 | goto out_unlock; | |
513 | } | |
514 | ||
515 | /* | |
516 | * Deactivate a channel. | |
517 | */ | |
518 | static void rxrpc_deactivate_one_channel(struct rxrpc_connection *conn, | |
519 | unsigned int channel) | |
520 | { | |
521 | struct rxrpc_channel *chan = &conn->channels[channel]; | |
522 | ||
523 | rcu_assign_pointer(chan->call, NULL); | |
524 | conn->active_chans &= ~(1 << channel); | |
525 | } | |
526 | ||
527 | /* | |
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 | |
530 | * to the world. | |
531 | */ | |
532 | static void rxrpc_activate_one_channel(struct rxrpc_connection *conn, | |
533 | unsigned int channel) | |
534 | { | |
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; | |
539 | ||
363deeab DH |
540 | trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate); |
541 | ||
af338a9e DH |
542 | write_lock_bh(&call->state_lock); |
543 | call->state = RXRPC_CALL_CLIENT_SEND_REQUEST; | |
544 | write_unlock_bh(&call->state_lock); | |
545 | ||
e34d4234 | 546 | rxrpc_see_call(call); |
45025bce DH |
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; | |
552 | ||
89ca6948 | 553 | trace_rxrpc_connect_call(call); |
45025bce DH |
554 | _net("CONNECT call %08x:%08x as call %d on conn %d", |
555 | call->cid, call->call_id, call->debug_id, conn->debug_id); | |
556 | ||
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. | |
560 | * | |
561 | * We provisionally assign a callNumber at this point, but we don't | |
562 | * confirm it until the call is about to be exposed. | |
563 | * | |
564 | * TODO: Pair with a barrier in the data_ready handler when that looks | |
565 | * at the call ID through a connection channel. | |
566 | */ | |
567 | smp_wmb(); | |
568 | chan->call_id = call_id; | |
569 | rcu_assign_pointer(chan->call, call); | |
570 | wake_up(&call->waitq); | |
571 | } | |
572 | ||
2629c7fa DH |
573 | /* |
574 | * Assign channels and callNumbers to waiting calls with channel_lock | |
575 | * held by caller. | |
576 | */ | |
577 | static void rxrpc_activate_channels_locked(struct rxrpc_connection *conn) | |
578 | { | |
579 | u8 avail, mask; | |
580 | ||
581 | switch (conn->cache_state) { | |
582 | case RXRPC_CONN_CLIENT_ACTIVE: | |
583 | mask = RXRPC_ACTIVE_CHANS_MASK; | |
584 | break; | |
585 | default: | |
586 | return; | |
587 | } | |
588 | ||
589 | while (!list_empty(&conn->waiting_calls) && | |
590 | (avail = ~conn->active_chans, | |
591 | avail &= mask, | |
592 | avail != 0)) | |
593 | rxrpc_activate_one_channel(conn, __ffs(avail)); | |
594 | } | |
595 | ||
45025bce DH |
596 | /* |
597 | * Assign channels and callNumbers to waiting calls. | |
598 | */ | |
599 | static void rxrpc_activate_channels(struct rxrpc_connection *conn) | |
600 | { | |
45025bce DH |
601 | _enter("%d", conn->debug_id); |
602 | ||
363deeab DH |
603 | trace_rxrpc_client(conn, -1, rxrpc_client_activate_chans); |
604 | ||
2629c7fa | 605 | if (conn->active_chans == RXRPC_ACTIVE_CHANS_MASK) |
45025bce DH |
606 | return; |
607 | ||
608 | spin_lock(&conn->channel_lock); | |
2629c7fa | 609 | rxrpc_activate_channels_locked(conn); |
45025bce DH |
610 | spin_unlock(&conn->channel_lock); |
611 | _leave(""); | |
612 | } | |
613 | ||
614 | /* | |
615 | * Wait for a callNumber and a channel to be granted to a call. | |
616 | */ | |
617 | static int rxrpc_wait_for_channel(struct rxrpc_call *call, gfp_t gfp) | |
618 | { | |
619 | int ret = 0; | |
620 | ||
621 | _enter("%d", call->debug_id); | |
622 | ||
623 | if (!call->call_id) { | |
624 | DECLARE_WAITQUEUE(myself, current); | |
c6d2b8d7 | 625 | |
c6d2b8d7 | 626 | if (!gfpflags_allow_blocking(gfp)) { |
45025bce DH |
627 | ret = -EAGAIN; |
628 | goto out; | |
c6d2b8d7 DH |
629 | } |
630 | ||
45025bce | 631 | add_wait_queue_exclusive(&call->waitq, &myself); |
c6d2b8d7 DH |
632 | for (;;) { |
633 | set_current_state(TASK_INTERRUPTIBLE); | |
45025bce DH |
634 | if (call->call_id) |
635 | break; | |
636 | if (signal_pending(current)) { | |
637 | ret = -ERESTARTSYS; | |
c6d2b8d7 | 638 | break; |
45025bce | 639 | } |
c6d2b8d7 DH |
640 | schedule(); |
641 | } | |
45025bce | 642 | remove_wait_queue(&call->waitq, &myself); |
c6d2b8d7 DH |
643 | __set_current_state(TASK_RUNNING); |
644 | } | |
645 | ||
45025bce DH |
646 | /* Paired with the write barrier in rxrpc_activate_one_channel(). */ |
647 | smp_rmb(); | |
648 | ||
649 | out: | |
650 | _leave(" = %d", ret); | |
651 | return ret; | |
652 | } | |
653 | ||
654 | /* | |
655 | * find a connection for a call | |
656 | * - called in process context with IRQs enabled | |
657 | */ | |
658 | int rxrpc_connect_call(struct rxrpc_call *call, | |
659 | struct rxrpc_conn_parameters *cp, | |
660 | struct sockaddr_rxrpc *srx, | |
661 | gfp_t gfp) | |
662 | { | |
663 | int ret; | |
664 | ||
665 | _enter("{%d,%lx},", call->debug_id, call->user_call_ID); | |
666 | ||
667 | rxrpc_discard_expired_client_conns(NULL); | |
668 | rxrpc_cull_active_client_conns(); | |
669 | ||
670 | ret = rxrpc_get_client_conn(call, cp, srx, gfp); | |
671 | if (ret < 0) | |
672 | return ret; | |
673 | ||
674 | rxrpc_animate_client_conn(call->conn); | |
675 | rxrpc_activate_channels(call->conn); | |
676 | ||
677 | ret = rxrpc_wait_for_channel(call, gfp); | |
678 | if (ret < 0) | |
679 | rxrpc_disconnect_client_call(call); | |
680 | ||
681 | _leave(" = %d", ret); | |
682 | return ret; | |
683 | } | |
684 | ||
685 | /* | |
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 | |
690 | * expensive). | |
691 | */ | |
363deeab DH |
692 | static void rxrpc_expose_client_conn(struct rxrpc_connection *conn, |
693 | unsigned int channel) | |
45025bce | 694 | { |
363deeab DH |
695 | if (!test_and_set_bit(RXRPC_CONN_EXPOSED, &conn->flags)) { |
696 | trace_rxrpc_client(conn, channel, rxrpc_client_exposed); | |
45025bce | 697 | rxrpc_get_connection(conn); |
363deeab | 698 | } |
45025bce DH |
699 | } |
700 | ||
701 | /* | |
702 | * Note that a call, and thus a connection, is about to be exposed to the | |
703 | * world. | |
704 | */ | |
705 | void rxrpc_expose_client_call(struct rxrpc_call *call) | |
706 | { | |
363deeab | 707 | unsigned int channel = call->cid & RXRPC_CHANNELMASK; |
45025bce | 708 | struct rxrpc_connection *conn = call->conn; |
363deeab | 709 | struct rxrpc_channel *chan = &conn->channels[channel]; |
45025bce DH |
710 | |
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 | |
715 | * wrap. | |
716 | */ | |
717 | chan->call_counter++; | |
718 | if (chan->call_counter >= INT_MAX) | |
719 | set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags); | |
363deeab | 720 | rxrpc_expose_client_conn(conn, channel); |
45025bce DH |
721 | } |
722 | } | |
723 | ||
724 | /* | |
725 | * Disconnect a client call. | |
726 | */ | |
727 | void rxrpc_disconnect_client_call(struct rxrpc_call *call) | |
728 | { | |
729 | unsigned int channel = call->cid & RXRPC_CHANNELMASK; | |
730 | struct rxrpc_connection *conn = call->conn; | |
731 | struct rxrpc_channel *chan = &conn->channels[channel]; | |
732 | ||
363deeab | 733 | trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect); |
45025bce DH |
734 | call->conn = NULL; |
735 | ||
c6d2b8d7 DH |
736 | spin_lock(&conn->channel_lock); |
737 | ||
45025bce DH |
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. | |
741 | */ | |
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); | |
747 | ||
363deeab DH |
748 | trace_rxrpc_client(conn, channel, rxrpc_client_chan_unstarted); |
749 | ||
45025bce DH |
750 | /* We must deactivate or idle the connection if it's now |
751 | * waiting for nothing. | |
752 | */ | |
753 | spin_lock(&rxrpc_client_conn_cache_lock); | |
754 | if (conn->cache_state == RXRPC_CONN_CLIENT_WAITING && | |
755 | list_empty(&conn->waiting_calls) && | |
756 | !conn->active_chans) | |
757 | goto idle_connection; | |
758 | goto out; | |
759 | } | |
760 | ||
761 | ASSERTCMP(rcu_access_pointer(chan->call), ==, call); | |
45025bce DH |
762 | |
763 | /* If a client call was exposed to the world, we save the result for | |
764 | * retransmission. | |
765 | * | |
766 | * We use a barrier here so that the call number and abort code can be | |
767 | * read without needing to take a lock. | |
768 | * | |
769 | * TODO: Make the incoming packet handler check this and handle | |
770 | * terminal retransmission without requiring access to the call. | |
771 | */ | |
772 | if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) { | |
f5c17aae | 773 | _debug("exposed %u,%u", call->call_id, call->abort_code); |
45025bce DH |
774 | __rxrpc_disconnect_call(conn, call); |
775 | } | |
776 | ||
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)) { | |
363deeab | 780 | trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass); |
45025bce DH |
781 | rxrpc_activate_one_channel(conn, channel); |
782 | goto out_2; | |
783 | } | |
784 | ||
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. | |
789 | */ | |
790 | spin_lock(&rxrpc_client_conn_cache_lock); | |
791 | ||
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; | |
799 | } | |
800 | goto out; | |
801 | } | |
802 | ||
363deeab | 803 | trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass); |
45025bce DH |
804 | rxrpc_activate_one_channel(conn, channel); |
805 | goto out; | |
806 | ||
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; | |
812 | goto out; | |
813 | ||
814 | case RXRPC_CONN_CLIENT_WAITING: | |
815 | rxrpc_deactivate_one_channel(conn, channel); | |
816 | goto out; | |
817 | ||
818 | default: | |
819 | BUG(); | |
820 | } | |
c6d2b8d7 | 821 | |
45025bce DH |
822 | out: |
823 | spin_unlock(&rxrpc_client_conn_cache_lock); | |
824 | out_2: | |
825 | spin_unlock(&conn->channel_lock); | |
c6d2b8d7 | 826 | rxrpc_put_connection(conn); |
45025bce DH |
827 | _leave(""); |
828 | return; | |
829 | ||
830 | idle_connection: | |
831 | /* As no channels remain active, the connection gets deactivated | |
832 | * immediately or moved to the idle list for a short while. | |
833 | */ | |
834 | if (test_bit(RXRPC_CONN_EXPOSED, &conn->flags)) { | |
363deeab | 835 | trace_rxrpc_client(conn, channel, rxrpc_client_to_idle); |
45025bce DH |
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); | |
844 | } else { | |
363deeab | 845 | trace_rxrpc_client(conn, channel, rxrpc_client_to_inactive); |
45025bce DH |
846 | conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE; |
847 | list_del_init(&conn->cache_link); | |
848 | } | |
849 | goto out; | |
c6d2b8d7 | 850 | } |
001c1122 DH |
851 | |
852 | /* | |
45025bce | 853 | * Clean up a dead client connection. |
001c1122 | 854 | */ |
45025bce DH |
855 | static struct rxrpc_connection * |
856 | rxrpc_put_one_client_conn(struct rxrpc_connection *conn) | |
001c1122 | 857 | { |
66d58af7 | 858 | struct rxrpc_connection *next = NULL; |
001c1122 | 859 | struct rxrpc_local *local = conn->params.local; |
45025bce | 860 | unsigned int nr_conns; |
001c1122 | 861 | |
363deeab DH |
862 | trace_rxrpc_client(conn, -1, rxrpc_client_cleanup); |
863 | ||
45025bce DH |
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, | |
867 | &conn->flags)) | |
868 | rb_erase(&conn->client_node, &local->client_conns); | |
869 | spin_unlock(&local->client_conns_lock); | |
870 | } | |
001c1122 DH |
871 | |
872 | rxrpc_put_client_connection_id(conn); | |
45025bce DH |
873 | |
874 | ASSERTCMP(conn->cache_state, ==, RXRPC_CONN_CLIENT_INACTIVE); | |
875 | ||
66d58af7 | 876 | if (test_bit(RXRPC_CONN_COUNTED, &conn->flags)) { |
363deeab | 877 | trace_rxrpc_client(conn, -1, rxrpc_client_uncount); |
66d58af7 DH |
878 | spin_lock(&rxrpc_client_conn_cache_lock); |
879 | nr_conns = --rxrpc_nr_client_conns; | |
880 | ||
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); | |
887 | } | |
45025bce | 888 | |
66d58af7 | 889 | spin_unlock(&rxrpc_client_conn_cache_lock); |
45025bce DH |
890 | } |
891 | ||
45025bce | 892 | rxrpc_kill_connection(conn); |
45025bce DH |
893 | if (next) |
894 | rxrpc_activate_channels(next); | |
895 | ||
896 | /* We need to get rid of the temporary ref we took upon next, but we | |
897 | * can't call rxrpc_put_connection() recursively. | |
898 | */ | |
899 | return next; | |
900 | } | |
901 | ||
902 | /* | |
903 | * Clean up a dead client connections. | |
904 | */ | |
905 | void rxrpc_put_client_conn(struct rxrpc_connection *conn) | |
906 | { | |
363deeab DH |
907 | const void *here = __builtin_return_address(0); |
908 | int n; | |
45025bce DH |
909 | |
910 | do { | |
363deeab DH |
911 | n = atomic_dec_return(&conn->usage); |
912 | trace_rxrpc_conn(conn, rxrpc_conn_put_client, n, here); | |
913 | if (n > 0) | |
914 | return; | |
915 | ASSERTCMP(n, >=, 0); | |
916 | ||
917 | conn = rxrpc_put_one_client_conn(conn); | |
918 | } while (conn); | |
45025bce DH |
919 | } |
920 | ||
921 | /* | |
922 | * Kill the longest-active client connections to make room for new ones. | |
923 | */ | |
924 | static void rxrpc_cull_active_client_conns(void) | |
925 | { | |
926 | struct rxrpc_connection *conn; | |
927 | unsigned int nr_conns = rxrpc_nr_client_conns; | |
928 | unsigned int nr_active, limit; | |
929 | ||
930 | _enter(""); | |
931 | ||
932 | ASSERTCMP(nr_conns, >=, 0); | |
933 | if (nr_conns < rxrpc_max_client_connections) { | |
934 | _leave(" [ok]"); | |
935 | return; | |
936 | } | |
937 | limit = rxrpc_reap_client_connections; | |
938 | ||
939 | spin_lock(&rxrpc_client_conn_cache_lock); | |
940 | nr_active = rxrpc_nr_active_client_conns; | |
941 | ||
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); | |
947 | ||
948 | if (list_empty(&conn->waiting_calls)) { | |
363deeab | 949 | trace_rxrpc_client(conn, -1, rxrpc_client_to_culled); |
45025bce DH |
950 | conn->cache_state = RXRPC_CONN_CLIENT_CULLED; |
951 | list_del_init(&conn->cache_link); | |
952 | } else { | |
363deeab | 953 | trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting); |
45025bce DH |
954 | conn->cache_state = RXRPC_CONN_CLIENT_WAITING; |
955 | list_move_tail(&conn->cache_link, | |
956 | &rxrpc_waiting_client_conns); | |
957 | } | |
958 | ||
959 | nr_active--; | |
960 | } | |
961 | ||
962 | rxrpc_nr_active_client_conns = nr_active; | |
963 | spin_unlock(&rxrpc_client_conn_cache_lock); | |
964 | ASSERTCMP(nr_active, >=, 0); | |
965 | _leave(" [culled]"); | |
966 | } | |
967 | ||
968 | /* | |
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. | |
971 | * | |
972 | * This may be called from conn setup or from a work item so cannot be | |
973 | * considered non-reentrant. | |
974 | */ | |
975 | static void rxrpc_discard_expired_client_conns(struct work_struct *work) | |
976 | { | |
977 | struct rxrpc_connection *conn; | |
978 | unsigned long expiry, conn_expires_at, now; | |
979 | unsigned int nr_conns; | |
980 | bool did_discard = false; | |
981 | ||
982 | _enter("%c", work ? 'w' : 'n'); | |
983 | ||
984 | if (list_empty(&rxrpc_idle_client_conns)) { | |
985 | _leave(" [empty]"); | |
986 | return; | |
987 | } | |
988 | ||
989 | /* Don't double up on the discarding */ | |
990 | if (!spin_trylock(&rxrpc_client_conn_discard_mutex)) { | |
991 | _leave(" [already]"); | |
992 | return; | |
993 | } | |
994 | ||
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. | |
997 | */ | |
998 | nr_conns = rxrpc_nr_client_conns; | |
999 | ||
1000 | next: | |
1001 | spin_lock(&rxrpc_client_conn_cache_lock); | |
1002 | ||
1003 | if (list_empty(&rxrpc_idle_client_conns)) | |
1004 | goto out; | |
1005 | ||
1006 | conn = list_entry(rxrpc_idle_client_conns.next, | |
1007 | struct rxrpc_connection, cache_link); | |
1008 | ASSERT(test_bit(RXRPC_CONN_EXPOSED, &conn->flags)); | |
1009 | ||
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. | |
1015 | */ | |
1016 | expiry = rxrpc_conn_idle_client_expiry; | |
1017 | if (nr_conns > rxrpc_reap_client_connections) | |
1018 | expiry = rxrpc_conn_idle_client_fast_expiry; | |
1019 | ||
1020 | conn_expires_at = conn->idle_timestamp + expiry; | |
1021 | ||
1022 | now = READ_ONCE(jiffies); | |
1023 | if (time_after(conn_expires_at, now)) | |
1024 | goto not_yet_expired; | |
1025 | } | |
1026 | ||
363deeab | 1027 | trace_rxrpc_client(conn, -1, rxrpc_client_discard); |
45025bce DH |
1028 | if (!test_and_clear_bit(RXRPC_CONN_EXPOSED, &conn->flags)) |
1029 | BUG(); | |
1030 | conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE; | |
1031 | list_del_init(&conn->cache_link); | |
1032 | ||
1033 | spin_unlock(&rxrpc_client_conn_cache_lock); | |
1034 | ||
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. | |
1038 | */ | |
1039 | rxrpc_put_connection(conn); | |
1040 | did_discard = true; | |
1041 | nr_conns--; | |
1042 | goto next; | |
1043 | ||
1044 | not_yet_expired: | |
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. | |
1047 | * | |
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. | |
1051 | */ | |
1052 | _debug("not yet"); | |
1053 | if (!rxrpc_kill_all_client_conns) | |
1054 | queue_delayed_work(rxrpc_workqueue, | |
1055 | &rxrpc_client_conn_reap, | |
1056 | conn_expires_at - now); | |
1057 | ||
1058 | out: | |
1059 | spin_unlock(&rxrpc_client_conn_cache_lock); | |
1060 | spin_unlock(&rxrpc_client_conn_discard_mutex); | |
1061 | _leave(""); | |
1062 | } | |
1063 | ||
1064 | /* | |
1065 | * Preemptively destroy all the client connection records rather than waiting | |
1066 | * for them to time out | |
1067 | */ | |
1068 | void __exit rxrpc_destroy_all_client_connections(void) | |
1069 | { | |
1070 | _enter(""); | |
1071 | ||
1072 | spin_lock(&rxrpc_client_conn_cache_lock); | |
1073 | rxrpc_kill_all_client_conns = true; | |
1074 | spin_unlock(&rxrpc_client_conn_cache_lock); | |
1075 | ||
1076 | cancel_delayed_work(&rxrpc_client_conn_reap); | |
1077 | ||
1078 | if (!queue_delayed_work(rxrpc_workqueue, &rxrpc_client_conn_reap, 0)) | |
1079 | _debug("destroy: queue failed"); | |
1080 | ||
1081 | _leave(""); | |
001c1122 | 1082 | } |