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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 | * | |
2baec2c3 | 34 | * The connection is on the rxnet->active_client_conns list which is kept |
45025bce DH |
35 | * in activation order for culling purposes. |
36 | * | |
37 | * rxrpc_nr_active_client_conns is held incremented also. | |
38 | * | |
4e255721 DH |
39 | * (4) UPGRADE - As for ACTIVE, but only one call may be in progress and is |
40 | * being used to probe for service upgrade. | |
41 | * | |
42 | * (5) CULLED - The connection got summarily culled to try and free up | |
45025bce DH |
43 | * capacity. Calls currently in progress on the connection are allowed to |
44 | * continue, but new calls will have to wait. There can be no waiters in | |
45 | * this state - the conn would have to go to the WAITING state instead. | |
46 | * | |
4e255721 | 47 | * (6) IDLE - The connection has no calls in progress upon it and must have |
45025bce DH |
48 | * been exposed to the world (ie. the EXPOSED flag must be set). When it |
49 | * expires, the EXPOSED flag is cleared and the connection transitions to | |
50 | * the INACTIVE state. | |
51 | * | |
2baec2c3 | 52 | * The connection is on the rxnet->idle_client_conns list which is kept in |
45025bce DH |
53 | * order of how soon they'll expire. |
54 | * | |
55 | * There are flags of relevance to the cache: | |
56 | * | |
57 | * (1) EXPOSED - The connection ID got exposed to the world. If this flag is | |
58 | * set, an extra ref is added to the connection preventing it from being | |
59 | * reaped when it has no calls outstanding. This flag is cleared and the | |
60 | * ref dropped when a conn is discarded from the idle list. | |
61 | * | |
62 | * This allows us to move terminal call state retransmission to the | |
63 | * connection and to discard the call immediately we think it is done | |
64 | * with. It also give us a chance to reuse the connection. | |
65 | * | |
66 | * (2) DONT_REUSE - The connection should be discarded as soon as possible and | |
67 | * should not be reused. This is set when an exclusive connection is used | |
68 | * or a call ID counter overflows. | |
69 | * | |
70 | * The caching state may only be changed if the cache lock is held. | |
71 | * | |
72 | * There are two idle client connection expiry durations. If the total number | |
73 | * of connections is below the reap threshold, we use the normal duration; if | |
74 | * it's above, we use the fast duration. | |
4a3388c8 DH |
75 | */ |
76 | ||
77 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
78 | ||
79 | #include <linux/slab.h> | |
80 | #include <linux/idr.h> | |
81 | #include <linux/timer.h> | |
174cd4b1 IM |
82 | #include <linux/sched/signal.h> |
83 | ||
4a3388c8 DH |
84 | #include "ar-internal.h" |
85 | ||
45025bce DH |
86 | __read_mostly unsigned int rxrpc_max_client_connections = 1000; |
87 | __read_mostly unsigned int rxrpc_reap_client_connections = 900; | |
88 | __read_mostly unsigned int rxrpc_conn_idle_client_expiry = 2 * 60 * HZ; | |
89 | __read_mostly unsigned int rxrpc_conn_idle_client_fast_expiry = 2 * HZ; | |
90 | ||
4a3388c8 DH |
91 | /* |
92 | * We use machine-unique IDs for our client connections. | |
93 | */ | |
94 | DEFINE_IDR(rxrpc_client_conn_ids); | |
95 | static DEFINE_SPINLOCK(rxrpc_conn_id_lock); | |
96 | ||
2baec2c3 | 97 | static void rxrpc_cull_active_client_conns(struct rxrpc_net *); |
45025bce | 98 | |
4a3388c8 DH |
99 | /* |
100 | * Get a connection ID and epoch for a client connection from the global pool. | |
101 | * The connection struct pointer is then recorded in the idr radix tree. The | |
090f85de DH |
102 | * epoch doesn't change until the client is rebooted (or, at least, unless the |
103 | * module is unloaded). | |
4a3388c8 | 104 | */ |
c6d2b8d7 DH |
105 | static int rxrpc_get_client_connection_id(struct rxrpc_connection *conn, |
106 | gfp_t gfp) | |
4a3388c8 | 107 | { |
2baec2c3 | 108 | struct rxrpc_net *rxnet = conn->params.local->rxnet; |
4a3388c8 DH |
109 | int id; |
110 | ||
111 | _enter(""); | |
112 | ||
113 | idr_preload(gfp); | |
4a3388c8 DH |
114 | spin_lock(&rxrpc_conn_id_lock); |
115 | ||
090f85de DH |
116 | id = idr_alloc_cyclic(&rxrpc_client_conn_ids, conn, |
117 | 1, 0x40000000, GFP_NOWAIT); | |
118 | if (id < 0) | |
119 | goto error; | |
4a3388c8 DH |
120 | |
121 | spin_unlock(&rxrpc_conn_id_lock); | |
4a3388c8 DH |
122 | idr_preload_end(); |
123 | ||
2baec2c3 | 124 | conn->proto.epoch = rxnet->epoch; |
4a3388c8 DH |
125 | conn->proto.cid = id << RXRPC_CIDSHIFT; |
126 | set_bit(RXRPC_CONN_HAS_IDR, &conn->flags); | |
090f85de | 127 | _leave(" [CID %x]", conn->proto.cid); |
4a3388c8 DH |
128 | return 0; |
129 | ||
130 | error: | |
131 | spin_unlock(&rxrpc_conn_id_lock); | |
4a3388c8 DH |
132 | idr_preload_end(); |
133 | _leave(" = %d", id); | |
134 | return id; | |
135 | } | |
136 | ||
137 | /* | |
138 | * Release a connection ID for a client connection from the global pool. | |
139 | */ | |
001c1122 | 140 | static void rxrpc_put_client_connection_id(struct rxrpc_connection *conn) |
4a3388c8 DH |
141 | { |
142 | if (test_bit(RXRPC_CONN_HAS_IDR, &conn->flags)) { | |
143 | spin_lock(&rxrpc_conn_id_lock); | |
144 | idr_remove(&rxrpc_client_conn_ids, | |
145 | conn->proto.cid >> RXRPC_CIDSHIFT); | |
146 | spin_unlock(&rxrpc_conn_id_lock); | |
147 | } | |
148 | } | |
eb9b9d22 DH |
149 | |
150 | /* | |
151 | * Destroy the client connection ID tree. | |
152 | */ | |
153 | void rxrpc_destroy_client_conn_ids(void) | |
154 | { | |
155 | struct rxrpc_connection *conn; | |
156 | int id; | |
157 | ||
158 | if (!idr_is_empty(&rxrpc_client_conn_ids)) { | |
159 | idr_for_each_entry(&rxrpc_client_conn_ids, conn, id) { | |
160 | pr_err("AF_RXRPC: Leaked client conn %p {%d}\n", | |
161 | conn, atomic_read(&conn->usage)); | |
162 | } | |
163 | BUG(); | |
164 | } | |
165 | ||
166 | idr_destroy(&rxrpc_client_conn_ids); | |
167 | } | |
c6d2b8d7 DH |
168 | |
169 | /* | |
45025bce | 170 | * Allocate a client connection. |
c6d2b8d7 DH |
171 | */ |
172 | static struct rxrpc_connection * | |
173 | rxrpc_alloc_client_connection(struct rxrpc_conn_parameters *cp, gfp_t gfp) | |
174 | { | |
175 | struct rxrpc_connection *conn; | |
2baec2c3 | 176 | struct rxrpc_net *rxnet = cp->local->rxnet; |
c6d2b8d7 DH |
177 | int ret; |
178 | ||
179 | _enter(""); | |
180 | ||
181 | conn = rxrpc_alloc_connection(gfp); | |
182 | if (!conn) { | |
183 | _leave(" = -ENOMEM"); | |
184 | return ERR_PTR(-ENOMEM); | |
185 | } | |
186 | ||
45025bce | 187 | atomic_set(&conn->usage, 1); |
8732db67 | 188 | if (cp->exclusive) |
45025bce | 189 | __set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags); |
4e255721 DH |
190 | if (cp->upgrade) |
191 | __set_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags); | |
45025bce | 192 | |
c6d2b8d7 | 193 | conn->params = *cp; |
c6d2b8d7 DH |
194 | conn->out_clientflag = RXRPC_CLIENT_INITIATED; |
195 | conn->state = RXRPC_CONN_CLIENT; | |
68d6d1ae | 196 | conn->service_id = cp->service_id; |
c6d2b8d7 | 197 | |
c6d2b8d7 DH |
198 | ret = rxrpc_get_client_connection_id(conn, gfp); |
199 | if (ret < 0) | |
200 | goto error_0; | |
201 | ||
202 | ret = rxrpc_init_client_conn_security(conn); | |
203 | if (ret < 0) | |
204 | goto error_1; | |
205 | ||
206 | ret = conn->security->prime_packet_security(conn); | |
207 | if (ret < 0) | |
208 | goto error_2; | |
209 | ||
2baec2c3 DH |
210 | write_lock(&rxnet->conn_lock); |
211 | list_add_tail(&conn->proc_link, &rxnet->conn_proc_list); | |
212 | write_unlock(&rxnet->conn_lock); | |
c6d2b8d7 DH |
213 | |
214 | /* We steal the caller's peer ref. */ | |
215 | cp->peer = NULL; | |
216 | rxrpc_get_local(conn->params.local); | |
217 | key_get(conn->params.key); | |
218 | ||
363deeab DH |
219 | trace_rxrpc_conn(conn, rxrpc_conn_new_client, atomic_read(&conn->usage), |
220 | __builtin_return_address(0)); | |
221 | trace_rxrpc_client(conn, -1, rxrpc_client_alloc); | |
c6d2b8d7 DH |
222 | _leave(" = %p", conn); |
223 | return conn; | |
224 | ||
225 | error_2: | |
226 | conn->security->clear(conn); | |
227 | error_1: | |
228 | rxrpc_put_client_connection_id(conn); | |
229 | error_0: | |
230 | kfree(conn); | |
231 | _leave(" = %d", ret); | |
232 | return ERR_PTR(ret); | |
233 | } | |
234 | ||
235 | /* | |
45025bce | 236 | * Determine if a connection may be reused. |
c6d2b8d7 | 237 | */ |
45025bce DH |
238 | static bool rxrpc_may_reuse_conn(struct rxrpc_connection *conn) |
239 | { | |
2baec2c3 | 240 | struct rxrpc_net *rxnet = conn->params.local->rxnet; |
45025bce DH |
241 | int id_cursor, id, distance, limit; |
242 | ||
243 | if (test_bit(RXRPC_CONN_DONT_REUSE, &conn->flags)) | |
244 | goto dont_reuse; | |
245 | ||
2baec2c3 | 246 | if (conn->proto.epoch != rxnet->epoch) |
45025bce DH |
247 | goto mark_dont_reuse; |
248 | ||
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. | |
254 | */ | |
44430612 | 255 | id_cursor = idr_get_cursor(&rxrpc_client_conn_ids); |
45025bce DH |
256 | id = conn->proto.cid >> RXRPC_CIDSHIFT; |
257 | distance = id - id_cursor; | |
258 | if (distance < 0) | |
259 | distance = -distance; | |
44430612 | 260 | limit = max(rxrpc_max_client_connections * 4, 1024U); |
45025bce DH |
261 | if (distance > limit) |
262 | goto mark_dont_reuse; | |
263 | ||
264 | return true; | |
265 | ||
266 | mark_dont_reuse: | |
267 | set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags); | |
268 | dont_reuse: | |
269 | return false; | |
270 | } | |
271 | ||
272 | /* | |
273 | * Create or find a client connection to use for a call. | |
274 | * | |
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. | |
277 | */ | |
278 | static int rxrpc_get_client_conn(struct rxrpc_call *call, | |
279 | struct rxrpc_conn_parameters *cp, | |
280 | struct sockaddr_rxrpc *srx, | |
281 | gfp_t gfp) | |
c6d2b8d7 DH |
282 | { |
283 | struct rxrpc_connection *conn, *candidate = NULL; | |
284 | struct rxrpc_local *local = cp->local; | |
285 | struct rb_node *p, **pp, *parent; | |
286 | long diff; | |
45025bce | 287 | int ret = -ENOMEM; |
c6d2b8d7 DH |
288 | |
289 | _enter("{%d,%lx},", call->debug_id, call->user_call_ID); | |
290 | ||
291 | cp->peer = rxrpc_lookup_peer(cp->local, srx, gfp); | |
292 | if (!cp->peer) | |
45025bce | 293 | goto error; |
c6d2b8d7 | 294 | |
f7aec129 DH |
295 | call->cong_cwnd = cp->peer->cong_cwnd; |
296 | if (call->cong_cwnd >= call->cong_ssthresh) | |
297 | call->cong_mode = RXRPC_CALL_CONGEST_AVOIDANCE; | |
298 | else | |
299 | call->cong_mode = RXRPC_CALL_SLOW_START; | |
300 | ||
45025bce DH |
301 | /* If the connection is not meant to be exclusive, search the available |
302 | * connections to see if the connection we want to use already exists. | |
303 | */ | |
c6d2b8d7 | 304 | if (!cp->exclusive) { |
c6d2b8d7 DH |
305 | _debug("search 1"); |
306 | spin_lock(&local->client_conns_lock); | |
307 | p = local->client_conns.rb_node; | |
308 | while (p) { | |
309 | conn = rb_entry(p, struct rxrpc_connection, client_node); | |
310 | ||
311 | #define cmp(X) ((long)conn->params.X - (long)cp->X) | |
312 | diff = (cmp(peer) ?: | |
313 | cmp(key) ?: | |
4e255721 DH |
314 | cmp(security_level) ?: |
315 | cmp(upgrade)); | |
45025bce DH |
316 | #undef cmp |
317 | if (diff < 0) { | |
c6d2b8d7 | 318 | p = p->rb_left; |
45025bce | 319 | } else if (diff > 0) { |
c6d2b8d7 | 320 | p = p->rb_right; |
45025bce DH |
321 | } else { |
322 | if (rxrpc_may_reuse_conn(conn) && | |
323 | rxrpc_get_connection_maybe(conn)) | |
324 | goto found_extant_conn; | |
325 | /* The connection needs replacing. It's better | |
326 | * to effect that when we have something to | |
327 | * replace it with so that we don't have to | |
328 | * rebalance the tree twice. | |
329 | */ | |
330 | break; | |
331 | } | |
c6d2b8d7 DH |
332 | } |
333 | spin_unlock(&local->client_conns_lock); | |
334 | } | |
335 | ||
45025bce DH |
336 | /* There wasn't a connection yet or we need an exclusive connection. |
337 | * We need to create a candidate and then potentially redo the search | |
338 | * in case we're racing with another thread also trying to connect on a | |
339 | * shareable connection. | |
340 | */ | |
341 | _debug("new conn"); | |
c6d2b8d7 | 342 | candidate = rxrpc_alloc_client_connection(cp, gfp); |
45025bce DH |
343 | if (IS_ERR(candidate)) { |
344 | ret = PTR_ERR(candidate); | |
345 | goto error_peer; | |
c6d2b8d7 DH |
346 | } |
347 | ||
45025bce DH |
348 | /* Add the call to the new connection's waiting list in case we're |
349 | * going to have to wait for the connection to come live. It's our | |
350 | * connection, so we want first dibs on the channel slots. We would | |
351 | * normally have to take channel_lock but we do this before anyone else | |
352 | * can see the connection. | |
353 | */ | |
354 | list_add_tail(&call->chan_wait_link, &candidate->waiting_calls); | |
355 | ||
c6d2b8d7 | 356 | if (cp->exclusive) { |
45025bce | 357 | call->conn = candidate; |
278ac0cd | 358 | call->security_ix = candidate->security_ix; |
68d6d1ae | 359 | call->service_id = candidate->service_id; |
45025bce DH |
360 | _leave(" = 0 [exclusive %d]", candidate->debug_id); |
361 | return 0; | |
c6d2b8d7 DH |
362 | } |
363 | ||
45025bce DH |
364 | /* Publish the new connection for userspace to find. We need to redo |
365 | * the search before doing this lest we race with someone else adding a | |
366 | * conflicting instance. | |
c6d2b8d7 DH |
367 | */ |
368 | _debug("search 2"); | |
369 | spin_lock(&local->client_conns_lock); | |
370 | ||
371 | pp = &local->client_conns.rb_node; | |
372 | parent = NULL; | |
373 | while (*pp) { | |
374 | parent = *pp; | |
375 | conn = rb_entry(parent, struct rxrpc_connection, client_node); | |
376 | ||
45025bce | 377 | #define cmp(X) ((long)conn->params.X - (long)candidate->params.X) |
c6d2b8d7 DH |
378 | diff = (cmp(peer) ?: |
379 | cmp(key) ?: | |
4e255721 DH |
380 | cmp(security_level) ?: |
381 | cmp(upgrade)); | |
45025bce DH |
382 | #undef cmp |
383 | if (diff < 0) { | |
c6d2b8d7 | 384 | pp = &(*pp)->rb_left; |
45025bce | 385 | } else if (diff > 0) { |
c6d2b8d7 | 386 | pp = &(*pp)->rb_right; |
45025bce DH |
387 | } else { |
388 | if (rxrpc_may_reuse_conn(conn) && | |
389 | rxrpc_get_connection_maybe(conn)) | |
390 | goto found_extant_conn; | |
391 | /* The old connection is from an outdated epoch. */ | |
392 | _debug("replace conn"); | |
393 | clear_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags); | |
394 | rb_replace_node(&conn->client_node, | |
395 | &candidate->client_node, | |
396 | &local->client_conns); | |
363deeab | 397 | trace_rxrpc_client(conn, -1, rxrpc_client_replace); |
45025bce DH |
398 | goto candidate_published; |
399 | } | |
c6d2b8d7 DH |
400 | } |
401 | ||
c6d2b8d7 | 402 | _debug("new conn"); |
001c1122 DH |
403 | rb_link_node(&candidate->client_node, parent, pp); |
404 | rb_insert_color(&candidate->client_node, &local->client_conns); | |
c6d2b8d7 | 405 | |
45025bce DH |
406 | candidate_published: |
407 | set_bit(RXRPC_CONN_IN_CLIENT_CONNS, &candidate->flags); | |
408 | call->conn = candidate; | |
278ac0cd | 409 | call->security_ix = candidate->security_ix; |
68d6d1ae | 410 | call->service_id = candidate->service_id; |
c6d2b8d7 | 411 | spin_unlock(&local->client_conns_lock); |
45025bce DH |
412 | _leave(" = 0 [new %d]", candidate->debug_id); |
413 | return 0; | |
c6d2b8d7 | 414 | |
45025bce DH |
415 | /* We come here if we found a suitable connection already in existence. |
416 | * Discard any candidate we may have allocated, and try to get a | |
417 | * channel on this one. | |
418 | */ | |
419 | found_extant_conn: | |
420 | _debug("found conn"); | |
421 | spin_unlock(&local->client_conns_lock); | |
c6d2b8d7 | 422 | |
363deeab DH |
423 | if (candidate) { |
424 | trace_rxrpc_client(candidate, -1, rxrpc_client_duplicate); | |
425 | rxrpc_put_connection(candidate); | |
426 | candidate = NULL; | |
427 | } | |
c6d2b8d7 | 428 | |
45025bce DH |
429 | spin_lock(&conn->channel_lock); |
430 | call->conn = conn; | |
278ac0cd | 431 | call->security_ix = conn->security_ix; |
68d6d1ae | 432 | call->service_id = conn->service_id; |
45025bce | 433 | list_add(&call->chan_wait_link, &conn->waiting_calls); |
c6d2b8d7 | 434 | spin_unlock(&conn->channel_lock); |
45025bce DH |
435 | _leave(" = 0 [extant %d]", conn->debug_id); |
436 | return 0; | |
437 | ||
438 | error_peer: | |
c6d2b8d7 DH |
439 | rxrpc_put_peer(cp->peer); |
440 | cp->peer = NULL; | |
45025bce DH |
441 | error: |
442 | _leave(" = %d", ret); | |
443 | return ret; | |
444 | } | |
c6d2b8d7 | 445 | |
45025bce DH |
446 | /* |
447 | * Activate a connection. | |
448 | */ | |
2baec2c3 DH |
449 | static void rxrpc_activate_conn(struct rxrpc_net *rxnet, |
450 | struct rxrpc_connection *conn) | |
45025bce | 451 | { |
4e255721 DH |
452 | if (test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags)) { |
453 | trace_rxrpc_client(conn, -1, rxrpc_client_to_upgrade); | |
454 | conn->cache_state = RXRPC_CONN_CLIENT_UPGRADE; | |
455 | } else { | |
456 | trace_rxrpc_client(conn, -1, rxrpc_client_to_active); | |
457 | conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE; | |
458 | } | |
2baec2c3 DH |
459 | rxnet->nr_active_client_conns++; |
460 | list_move_tail(&conn->cache_link, &rxnet->active_client_conns); | |
45025bce DH |
461 | } |
462 | ||
463 | /* | |
464 | * Attempt to animate a connection for a new call. | |
465 | * | |
466 | * If it's not exclusive, the connection is in the endpoint tree, and we're in | |
467 | * the conn's list of those waiting to grab a channel. There is, however, a | |
468 | * limit on the number of live connections allowed at any one time, so we may | |
469 | * have to wait for capacity to become available. | |
470 | * | |
471 | * Note that a connection on the waiting queue might *also* have active | |
472 | * channels if it has been culled to make space and then re-requested by a new | |
473 | * call. | |
474 | */ | |
2baec2c3 DH |
475 | static void rxrpc_animate_client_conn(struct rxrpc_net *rxnet, |
476 | struct rxrpc_connection *conn) | |
45025bce DH |
477 | { |
478 | unsigned int nr_conns; | |
479 | ||
480 | _enter("%d,%d", conn->debug_id, conn->cache_state); | |
481 | ||
4e255721 DH |
482 | if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE || |
483 | conn->cache_state == RXRPC_CONN_CLIENT_UPGRADE) | |
45025bce DH |
484 | goto out; |
485 | ||
2baec2c3 | 486 | spin_lock(&rxnet->client_conn_cache_lock); |
45025bce | 487 | |
2baec2c3 | 488 | nr_conns = rxnet->nr_client_conns; |
363deeab DH |
489 | if (!test_and_set_bit(RXRPC_CONN_COUNTED, &conn->flags)) { |
490 | trace_rxrpc_client(conn, -1, rxrpc_client_count); | |
2baec2c3 | 491 | rxnet->nr_client_conns = nr_conns + 1; |
363deeab | 492 | } |
45025bce DH |
493 | |
494 | switch (conn->cache_state) { | |
495 | case RXRPC_CONN_CLIENT_ACTIVE: | |
4e255721 | 496 | case RXRPC_CONN_CLIENT_UPGRADE: |
45025bce DH |
497 | case RXRPC_CONN_CLIENT_WAITING: |
498 | break; | |
499 | ||
500 | case RXRPC_CONN_CLIENT_INACTIVE: | |
501 | case RXRPC_CONN_CLIENT_CULLED: | |
502 | case RXRPC_CONN_CLIENT_IDLE: | |
503 | if (nr_conns >= rxrpc_max_client_connections) | |
504 | goto wait_for_capacity; | |
505 | goto activate_conn; | |
506 | ||
507 | default: | |
508 | BUG(); | |
001c1122 DH |
509 | } |
510 | ||
45025bce | 511 | out_unlock: |
2baec2c3 | 512 | spin_unlock(&rxnet->client_conn_cache_lock); |
45025bce DH |
513 | out: |
514 | _leave(" [%d]", conn->cache_state); | |
515 | return; | |
c6d2b8d7 | 516 | |
45025bce DH |
517 | activate_conn: |
518 | _debug("activate"); | |
2baec2c3 | 519 | rxrpc_activate_conn(rxnet, conn); |
45025bce DH |
520 | goto out_unlock; |
521 | ||
522 | wait_for_capacity: | |
523 | _debug("wait"); | |
363deeab | 524 | trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting); |
45025bce | 525 | conn->cache_state = RXRPC_CONN_CLIENT_WAITING; |
2baec2c3 | 526 | list_move_tail(&conn->cache_link, &rxnet->waiting_client_conns); |
45025bce DH |
527 | goto out_unlock; |
528 | } | |
529 | ||
530 | /* | |
531 | * Deactivate a channel. | |
532 | */ | |
533 | static void rxrpc_deactivate_one_channel(struct rxrpc_connection *conn, | |
534 | unsigned int channel) | |
535 | { | |
536 | struct rxrpc_channel *chan = &conn->channels[channel]; | |
537 | ||
538 | rcu_assign_pointer(chan->call, NULL); | |
539 | conn->active_chans &= ~(1 << channel); | |
540 | } | |
541 | ||
542 | /* | |
543 | * Assign a channel to the call at the front of the queue and wake the call up. | |
544 | * We don't increment the callNumber counter until this number has been exposed | |
545 | * to the world. | |
546 | */ | |
547 | static void rxrpc_activate_one_channel(struct rxrpc_connection *conn, | |
548 | unsigned int channel) | |
549 | { | |
550 | struct rxrpc_channel *chan = &conn->channels[channel]; | |
551 | struct rxrpc_call *call = list_entry(conn->waiting_calls.next, | |
552 | struct rxrpc_call, chan_wait_link); | |
553 | u32 call_id = chan->call_counter + 1; | |
554 | ||
363deeab DH |
555 | trace_rxrpc_client(conn, channel, rxrpc_client_chan_activate); |
556 | ||
3136ef49 DH |
557 | /* Cancel the final ACK on the previous call if it hasn't been sent yet |
558 | * as the DATA packet will implicitly ACK it. | |
559 | */ | |
560 | clear_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags); | |
561 | ||
af338a9e | 562 | write_lock_bh(&call->state_lock); |
c038a58c DH |
563 | if (!test_bit(RXRPC_CALL_TX_LASTQ, &call->flags)) |
564 | call->state = RXRPC_CALL_CLIENT_SEND_REQUEST; | |
565 | else | |
566 | call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY; | |
af338a9e DH |
567 | write_unlock_bh(&call->state_lock); |
568 | ||
e34d4234 | 569 | rxrpc_see_call(call); |
45025bce DH |
570 | list_del_init(&call->chan_wait_link); |
571 | conn->active_chans |= 1 << channel; | |
572 | call->peer = rxrpc_get_peer(conn->params.peer); | |
573 | call->cid = conn->proto.cid | channel; | |
574 | call->call_id = call_id; | |
575 | ||
89ca6948 | 576 | trace_rxrpc_connect_call(call); |
45025bce DH |
577 | _net("CONNECT call %08x:%08x as call %d on conn %d", |
578 | call->cid, call->call_id, call->debug_id, conn->debug_id); | |
579 | ||
580 | /* Paired with the read barrier in rxrpc_wait_for_channel(). This | |
581 | * orders cid and epoch in the connection wrt to call_id without the | |
582 | * need to take the channel_lock. | |
583 | * | |
584 | * We provisionally assign a callNumber at this point, but we don't | |
585 | * confirm it until the call is about to be exposed. | |
586 | * | |
587 | * TODO: Pair with a barrier in the data_ready handler when that looks | |
588 | * at the call ID through a connection channel. | |
589 | */ | |
590 | smp_wmb(); | |
591 | chan->call_id = call_id; | |
592 | rcu_assign_pointer(chan->call, call); | |
593 | wake_up(&call->waitq); | |
594 | } | |
595 | ||
2629c7fa DH |
596 | /* |
597 | * Assign channels and callNumbers to waiting calls with channel_lock | |
598 | * held by caller. | |
599 | */ | |
600 | static void rxrpc_activate_channels_locked(struct rxrpc_connection *conn) | |
601 | { | |
602 | u8 avail, mask; | |
603 | ||
604 | switch (conn->cache_state) { | |
605 | case RXRPC_CONN_CLIENT_ACTIVE: | |
606 | mask = RXRPC_ACTIVE_CHANS_MASK; | |
607 | break; | |
4e255721 DH |
608 | case RXRPC_CONN_CLIENT_UPGRADE: |
609 | mask = 0x01; | |
610 | break; | |
2629c7fa DH |
611 | default: |
612 | return; | |
613 | } | |
614 | ||
615 | while (!list_empty(&conn->waiting_calls) && | |
616 | (avail = ~conn->active_chans, | |
617 | avail &= mask, | |
618 | avail != 0)) | |
619 | rxrpc_activate_one_channel(conn, __ffs(avail)); | |
620 | } | |
621 | ||
45025bce DH |
622 | /* |
623 | * Assign channels and callNumbers to waiting calls. | |
624 | */ | |
625 | static void rxrpc_activate_channels(struct rxrpc_connection *conn) | |
626 | { | |
45025bce DH |
627 | _enter("%d", conn->debug_id); |
628 | ||
363deeab DH |
629 | trace_rxrpc_client(conn, -1, rxrpc_client_activate_chans); |
630 | ||
2629c7fa | 631 | if (conn->active_chans == RXRPC_ACTIVE_CHANS_MASK) |
45025bce DH |
632 | return; |
633 | ||
634 | spin_lock(&conn->channel_lock); | |
2629c7fa | 635 | rxrpc_activate_channels_locked(conn); |
45025bce DH |
636 | spin_unlock(&conn->channel_lock); |
637 | _leave(""); | |
638 | } | |
639 | ||
640 | /* | |
641 | * Wait for a callNumber and a channel to be granted to a call. | |
642 | */ | |
643 | static int rxrpc_wait_for_channel(struct rxrpc_call *call, gfp_t gfp) | |
644 | { | |
645 | int ret = 0; | |
646 | ||
647 | _enter("%d", call->debug_id); | |
648 | ||
649 | if (!call->call_id) { | |
650 | DECLARE_WAITQUEUE(myself, current); | |
c6d2b8d7 | 651 | |
c6d2b8d7 | 652 | if (!gfpflags_allow_blocking(gfp)) { |
45025bce DH |
653 | ret = -EAGAIN; |
654 | goto out; | |
c6d2b8d7 DH |
655 | } |
656 | ||
45025bce | 657 | add_wait_queue_exclusive(&call->waitq, &myself); |
c6d2b8d7 DH |
658 | for (;;) { |
659 | set_current_state(TASK_INTERRUPTIBLE); | |
45025bce DH |
660 | if (call->call_id) |
661 | break; | |
662 | if (signal_pending(current)) { | |
663 | ret = -ERESTARTSYS; | |
c6d2b8d7 | 664 | break; |
45025bce | 665 | } |
c6d2b8d7 DH |
666 | schedule(); |
667 | } | |
45025bce | 668 | remove_wait_queue(&call->waitq, &myself); |
c6d2b8d7 DH |
669 | __set_current_state(TASK_RUNNING); |
670 | } | |
671 | ||
45025bce DH |
672 | /* Paired with the write barrier in rxrpc_activate_one_channel(). */ |
673 | smp_rmb(); | |
674 | ||
675 | out: | |
676 | _leave(" = %d", ret); | |
677 | return ret; | |
678 | } | |
679 | ||
680 | /* | |
681 | * find a connection for a call | |
682 | * - called in process context with IRQs enabled | |
683 | */ | |
684 | int rxrpc_connect_call(struct rxrpc_call *call, | |
685 | struct rxrpc_conn_parameters *cp, | |
686 | struct sockaddr_rxrpc *srx, | |
687 | gfp_t gfp) | |
688 | { | |
2baec2c3 | 689 | struct rxrpc_net *rxnet = cp->local->rxnet; |
45025bce DH |
690 | int ret; |
691 | ||
692 | _enter("{%d,%lx},", call->debug_id, call->user_call_ID); | |
693 | ||
2baec2c3 DH |
694 | rxrpc_discard_expired_client_conns(&rxnet->client_conn_reaper.work); |
695 | rxrpc_cull_active_client_conns(rxnet); | |
45025bce DH |
696 | |
697 | ret = rxrpc_get_client_conn(call, cp, srx, gfp); | |
698 | if (ret < 0) | |
c038a58c | 699 | goto out; |
45025bce | 700 | |
2baec2c3 | 701 | rxrpc_animate_client_conn(rxnet, call->conn); |
45025bce DH |
702 | rxrpc_activate_channels(call->conn); |
703 | ||
704 | ret = rxrpc_wait_for_channel(call, gfp); | |
c038a58c | 705 | if (ret < 0) { |
45025bce | 706 | rxrpc_disconnect_client_call(call); |
c038a58c DH |
707 | goto out; |
708 | } | |
709 | ||
710 | spin_lock_bh(&call->conn->params.peer->lock); | |
711 | hlist_add_head(&call->error_link, | |
712 | &call->conn->params.peer->error_targets); | |
713 | spin_unlock_bh(&call->conn->params.peer->lock); | |
45025bce | 714 | |
c038a58c | 715 | out: |
45025bce DH |
716 | _leave(" = %d", ret); |
717 | return ret; | |
718 | } | |
719 | ||
720 | /* | |
721 | * Note that a connection is about to be exposed to the world. Once it is | |
722 | * exposed, we maintain an extra ref on it that stops it from being summarily | |
723 | * discarded before it's (a) had a chance to deal with retransmission and (b) | |
724 | * had a chance at re-use (the per-connection security negotiation is | |
725 | * expensive). | |
726 | */ | |
363deeab DH |
727 | static void rxrpc_expose_client_conn(struct rxrpc_connection *conn, |
728 | unsigned int channel) | |
45025bce | 729 | { |
363deeab DH |
730 | if (!test_and_set_bit(RXRPC_CONN_EXPOSED, &conn->flags)) { |
731 | trace_rxrpc_client(conn, channel, rxrpc_client_exposed); | |
45025bce | 732 | rxrpc_get_connection(conn); |
363deeab | 733 | } |
45025bce DH |
734 | } |
735 | ||
736 | /* | |
737 | * Note that a call, and thus a connection, is about to be exposed to the | |
738 | * world. | |
739 | */ | |
740 | void rxrpc_expose_client_call(struct rxrpc_call *call) | |
741 | { | |
363deeab | 742 | unsigned int channel = call->cid & RXRPC_CHANNELMASK; |
45025bce | 743 | struct rxrpc_connection *conn = call->conn; |
363deeab | 744 | struct rxrpc_channel *chan = &conn->channels[channel]; |
45025bce DH |
745 | |
746 | if (!test_and_set_bit(RXRPC_CALL_EXPOSED, &call->flags)) { | |
747 | /* Mark the call ID as being used. If the callNumber counter | |
748 | * exceeds ~2 billion, we kill the connection after its | |
749 | * outstanding calls have finished so that the counter doesn't | |
750 | * wrap. | |
751 | */ | |
752 | chan->call_counter++; | |
753 | if (chan->call_counter >= INT_MAX) | |
754 | set_bit(RXRPC_CONN_DONT_REUSE, &conn->flags); | |
363deeab | 755 | rxrpc_expose_client_conn(conn, channel); |
45025bce DH |
756 | } |
757 | } | |
758 | ||
759 | /* | |
760 | * Disconnect a client call. | |
761 | */ | |
762 | void rxrpc_disconnect_client_call(struct rxrpc_call *call) | |
763 | { | |
764 | unsigned int channel = call->cid & RXRPC_CHANNELMASK; | |
765 | struct rxrpc_connection *conn = call->conn; | |
766 | struct rxrpc_channel *chan = &conn->channels[channel]; | |
2baec2c3 | 767 | struct rxrpc_net *rxnet = rxrpc_net(sock_net(&call->socket->sk)); |
45025bce | 768 | |
363deeab | 769 | trace_rxrpc_client(conn, channel, rxrpc_client_chan_disconnect); |
45025bce DH |
770 | call->conn = NULL; |
771 | ||
c6d2b8d7 DH |
772 | spin_lock(&conn->channel_lock); |
773 | ||
45025bce DH |
774 | /* Calls that have never actually been assigned a channel can simply be |
775 | * discarded. If the conn didn't get used either, it will follow | |
776 | * immediately unless someone else grabs it in the meantime. | |
777 | */ | |
778 | if (!list_empty(&call->chan_wait_link)) { | |
779 | _debug("call is waiting"); | |
780 | ASSERTCMP(call->call_id, ==, 0); | |
781 | ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags)); | |
782 | list_del_init(&call->chan_wait_link); | |
783 | ||
363deeab DH |
784 | trace_rxrpc_client(conn, channel, rxrpc_client_chan_unstarted); |
785 | ||
45025bce DH |
786 | /* We must deactivate or idle the connection if it's now |
787 | * waiting for nothing. | |
788 | */ | |
2baec2c3 | 789 | spin_lock(&rxnet->client_conn_cache_lock); |
45025bce DH |
790 | if (conn->cache_state == RXRPC_CONN_CLIENT_WAITING && |
791 | list_empty(&conn->waiting_calls) && | |
792 | !conn->active_chans) | |
793 | goto idle_connection; | |
794 | goto out; | |
795 | } | |
796 | ||
797 | ASSERTCMP(rcu_access_pointer(chan->call), ==, call); | |
45025bce DH |
798 | |
799 | /* If a client call was exposed to the world, we save the result for | |
800 | * retransmission. | |
801 | * | |
802 | * We use a barrier here so that the call number and abort code can be | |
803 | * read without needing to take a lock. | |
804 | * | |
805 | * TODO: Make the incoming packet handler check this and handle | |
806 | * terminal retransmission without requiring access to the call. | |
807 | */ | |
808 | if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) { | |
f5c17aae | 809 | _debug("exposed %u,%u", call->call_id, call->abort_code); |
45025bce DH |
810 | __rxrpc_disconnect_call(conn, call); |
811 | } | |
812 | ||
813 | /* See if we can pass the channel directly to another call. */ | |
814 | if (conn->cache_state == RXRPC_CONN_CLIENT_ACTIVE && | |
815 | !list_empty(&conn->waiting_calls)) { | |
363deeab | 816 | trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass); |
45025bce DH |
817 | rxrpc_activate_one_channel(conn, channel); |
818 | goto out_2; | |
819 | } | |
820 | ||
3136ef49 DH |
821 | /* Schedule the final ACK to be transmitted in a short while so that it |
822 | * can be skipped if we find a follow-on call. The first DATA packet | |
823 | * of the follow on call will implicitly ACK this call. | |
824 | */ | |
825 | if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) { | |
826 | unsigned long final_ack_at = jiffies + 2; | |
827 | ||
828 | WRITE_ONCE(chan->final_ack_at, final_ack_at); | |
829 | smp_wmb(); /* vs rxrpc_process_delayed_final_acks() */ | |
830 | set_bit(RXRPC_CONN_FINAL_ACK_0 + channel, &conn->flags); | |
831 | rxrpc_reduce_conn_timer(conn, final_ack_at); | |
832 | } | |
833 | ||
45025bce DH |
834 | /* Things are more complex and we need the cache lock. We might be |
835 | * able to simply idle the conn or it might now be lurking on the wait | |
836 | * list. It might even get moved back to the active list whilst we're | |
837 | * waiting for the lock. | |
838 | */ | |
2baec2c3 | 839 | spin_lock(&rxnet->client_conn_cache_lock); |
45025bce DH |
840 | |
841 | switch (conn->cache_state) { | |
4e255721 DH |
842 | case RXRPC_CONN_CLIENT_UPGRADE: |
843 | /* Deal with termination of a service upgrade probe. */ | |
844 | if (test_bit(RXRPC_CONN_EXPOSED, &conn->flags)) { | |
845 | clear_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags); | |
846 | trace_rxrpc_client(conn, channel, rxrpc_client_to_active); | |
847 | conn->cache_state = RXRPC_CONN_CLIENT_ACTIVE; | |
848 | rxrpc_activate_channels_locked(conn); | |
849 | } | |
850 | /* fall through */ | |
45025bce DH |
851 | case RXRPC_CONN_CLIENT_ACTIVE: |
852 | if (list_empty(&conn->waiting_calls)) { | |
853 | rxrpc_deactivate_one_channel(conn, channel); | |
854 | if (!conn->active_chans) { | |
2baec2c3 | 855 | rxnet->nr_active_client_conns--; |
45025bce DH |
856 | goto idle_connection; |
857 | } | |
858 | goto out; | |
859 | } | |
860 | ||
363deeab | 861 | trace_rxrpc_client(conn, channel, rxrpc_client_chan_pass); |
45025bce DH |
862 | rxrpc_activate_one_channel(conn, channel); |
863 | goto out; | |
864 | ||
865 | case RXRPC_CONN_CLIENT_CULLED: | |
866 | rxrpc_deactivate_one_channel(conn, channel); | |
867 | ASSERT(list_empty(&conn->waiting_calls)); | |
868 | if (!conn->active_chans) | |
869 | goto idle_connection; | |
870 | goto out; | |
871 | ||
872 | case RXRPC_CONN_CLIENT_WAITING: | |
873 | rxrpc_deactivate_one_channel(conn, channel); | |
874 | goto out; | |
875 | ||
876 | default: | |
877 | BUG(); | |
878 | } | |
c6d2b8d7 | 879 | |
45025bce | 880 | out: |
2baec2c3 | 881 | spin_unlock(&rxnet->client_conn_cache_lock); |
45025bce DH |
882 | out_2: |
883 | spin_unlock(&conn->channel_lock); | |
c6d2b8d7 | 884 | rxrpc_put_connection(conn); |
45025bce DH |
885 | _leave(""); |
886 | return; | |
887 | ||
888 | idle_connection: | |
889 | /* As no channels remain active, the connection gets deactivated | |
890 | * immediately or moved to the idle list for a short while. | |
891 | */ | |
892 | if (test_bit(RXRPC_CONN_EXPOSED, &conn->flags)) { | |
363deeab | 893 | trace_rxrpc_client(conn, channel, rxrpc_client_to_idle); |
45025bce DH |
894 | conn->idle_timestamp = jiffies; |
895 | conn->cache_state = RXRPC_CONN_CLIENT_IDLE; | |
2baec2c3 DH |
896 | list_move_tail(&conn->cache_link, &rxnet->idle_client_conns); |
897 | if (rxnet->idle_client_conns.next == &conn->cache_link && | |
898 | !rxnet->kill_all_client_conns) | |
45025bce | 899 | queue_delayed_work(rxrpc_workqueue, |
2baec2c3 | 900 | &rxnet->client_conn_reaper, |
45025bce DH |
901 | rxrpc_conn_idle_client_expiry); |
902 | } else { | |
363deeab | 903 | trace_rxrpc_client(conn, channel, rxrpc_client_to_inactive); |
45025bce DH |
904 | conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE; |
905 | list_del_init(&conn->cache_link); | |
906 | } | |
907 | goto out; | |
c6d2b8d7 | 908 | } |
001c1122 DH |
909 | |
910 | /* | |
45025bce | 911 | * Clean up a dead client connection. |
001c1122 | 912 | */ |
45025bce DH |
913 | static struct rxrpc_connection * |
914 | rxrpc_put_one_client_conn(struct rxrpc_connection *conn) | |
001c1122 | 915 | { |
66d58af7 | 916 | struct rxrpc_connection *next = NULL; |
001c1122 | 917 | struct rxrpc_local *local = conn->params.local; |
2baec2c3 | 918 | struct rxrpc_net *rxnet = local->rxnet; |
45025bce | 919 | unsigned int nr_conns; |
001c1122 | 920 | |
363deeab DH |
921 | trace_rxrpc_client(conn, -1, rxrpc_client_cleanup); |
922 | ||
45025bce DH |
923 | if (test_bit(RXRPC_CONN_IN_CLIENT_CONNS, &conn->flags)) { |
924 | spin_lock(&local->client_conns_lock); | |
925 | if (test_and_clear_bit(RXRPC_CONN_IN_CLIENT_CONNS, | |
926 | &conn->flags)) | |
927 | rb_erase(&conn->client_node, &local->client_conns); | |
928 | spin_unlock(&local->client_conns_lock); | |
929 | } | |
001c1122 DH |
930 | |
931 | rxrpc_put_client_connection_id(conn); | |
45025bce DH |
932 | |
933 | ASSERTCMP(conn->cache_state, ==, RXRPC_CONN_CLIENT_INACTIVE); | |
934 | ||
66d58af7 | 935 | if (test_bit(RXRPC_CONN_COUNTED, &conn->flags)) { |
363deeab | 936 | trace_rxrpc_client(conn, -1, rxrpc_client_uncount); |
2baec2c3 DH |
937 | spin_lock(&rxnet->client_conn_cache_lock); |
938 | nr_conns = --rxnet->nr_client_conns; | |
66d58af7 DH |
939 | |
940 | if (nr_conns < rxrpc_max_client_connections && | |
2baec2c3 DH |
941 | !list_empty(&rxnet->waiting_client_conns)) { |
942 | next = list_entry(rxnet->waiting_client_conns.next, | |
66d58af7 DH |
943 | struct rxrpc_connection, cache_link); |
944 | rxrpc_get_connection(next); | |
2baec2c3 | 945 | rxrpc_activate_conn(rxnet, next); |
66d58af7 | 946 | } |
45025bce | 947 | |
2baec2c3 | 948 | spin_unlock(&rxnet->client_conn_cache_lock); |
45025bce DH |
949 | } |
950 | ||
45025bce | 951 | rxrpc_kill_connection(conn); |
45025bce DH |
952 | if (next) |
953 | rxrpc_activate_channels(next); | |
954 | ||
955 | /* We need to get rid of the temporary ref we took upon next, but we | |
956 | * can't call rxrpc_put_connection() recursively. | |
957 | */ | |
958 | return next; | |
959 | } | |
960 | ||
961 | /* | |
962 | * Clean up a dead client connections. | |
963 | */ | |
964 | void rxrpc_put_client_conn(struct rxrpc_connection *conn) | |
965 | { | |
363deeab DH |
966 | const void *here = __builtin_return_address(0); |
967 | int n; | |
45025bce DH |
968 | |
969 | do { | |
363deeab DH |
970 | n = atomic_dec_return(&conn->usage); |
971 | trace_rxrpc_conn(conn, rxrpc_conn_put_client, n, here); | |
972 | if (n > 0) | |
973 | return; | |
974 | ASSERTCMP(n, >=, 0); | |
975 | ||
976 | conn = rxrpc_put_one_client_conn(conn); | |
977 | } while (conn); | |
45025bce DH |
978 | } |
979 | ||
980 | /* | |
981 | * Kill the longest-active client connections to make room for new ones. | |
982 | */ | |
2baec2c3 | 983 | static void rxrpc_cull_active_client_conns(struct rxrpc_net *rxnet) |
45025bce DH |
984 | { |
985 | struct rxrpc_connection *conn; | |
2baec2c3 | 986 | unsigned int nr_conns = rxnet->nr_client_conns; |
45025bce DH |
987 | unsigned int nr_active, limit; |
988 | ||
989 | _enter(""); | |
990 | ||
991 | ASSERTCMP(nr_conns, >=, 0); | |
992 | if (nr_conns < rxrpc_max_client_connections) { | |
993 | _leave(" [ok]"); | |
994 | return; | |
995 | } | |
996 | limit = rxrpc_reap_client_connections; | |
997 | ||
2baec2c3 DH |
998 | spin_lock(&rxnet->client_conn_cache_lock); |
999 | nr_active = rxnet->nr_active_client_conns; | |
45025bce DH |
1000 | |
1001 | while (nr_active > limit) { | |
2baec2c3 DH |
1002 | ASSERT(!list_empty(&rxnet->active_client_conns)); |
1003 | conn = list_entry(rxnet->active_client_conns.next, | |
45025bce | 1004 | struct rxrpc_connection, cache_link); |
4e255721 DH |
1005 | ASSERTIFCMP(conn->cache_state != RXRPC_CONN_CLIENT_ACTIVE, |
1006 | conn->cache_state, ==, RXRPC_CONN_CLIENT_UPGRADE); | |
45025bce DH |
1007 | |
1008 | if (list_empty(&conn->waiting_calls)) { | |
363deeab | 1009 | trace_rxrpc_client(conn, -1, rxrpc_client_to_culled); |
45025bce DH |
1010 | conn->cache_state = RXRPC_CONN_CLIENT_CULLED; |
1011 | list_del_init(&conn->cache_link); | |
1012 | } else { | |
363deeab | 1013 | trace_rxrpc_client(conn, -1, rxrpc_client_to_waiting); |
45025bce DH |
1014 | conn->cache_state = RXRPC_CONN_CLIENT_WAITING; |
1015 | list_move_tail(&conn->cache_link, | |
2baec2c3 | 1016 | &rxnet->waiting_client_conns); |
45025bce DH |
1017 | } |
1018 | ||
1019 | nr_active--; | |
1020 | } | |
1021 | ||
2baec2c3 DH |
1022 | rxnet->nr_active_client_conns = nr_active; |
1023 | spin_unlock(&rxnet->client_conn_cache_lock); | |
45025bce DH |
1024 | ASSERTCMP(nr_active, >=, 0); |
1025 | _leave(" [culled]"); | |
1026 | } | |
1027 | ||
1028 | /* | |
1029 | * Discard expired client connections from the idle list. Each conn in the | |
1030 | * idle list has been exposed and holds an extra ref because of that. | |
1031 | * | |
1032 | * This may be called from conn setup or from a work item so cannot be | |
1033 | * considered non-reentrant. | |
1034 | */ | |
2baec2c3 | 1035 | void rxrpc_discard_expired_client_conns(struct work_struct *work) |
45025bce DH |
1036 | { |
1037 | struct rxrpc_connection *conn; | |
2baec2c3 DH |
1038 | struct rxrpc_net *rxnet = |
1039 | container_of(to_delayed_work(work), | |
1040 | struct rxrpc_net, client_conn_reaper); | |
45025bce DH |
1041 | unsigned long expiry, conn_expires_at, now; |
1042 | unsigned int nr_conns; | |
1043 | bool did_discard = false; | |
1044 | ||
2baec2c3 | 1045 | _enter(""); |
45025bce | 1046 | |
2baec2c3 | 1047 | if (list_empty(&rxnet->idle_client_conns)) { |
45025bce DH |
1048 | _leave(" [empty]"); |
1049 | return; | |
1050 | } | |
1051 | ||
1052 | /* Don't double up on the discarding */ | |
2baec2c3 | 1053 | if (!spin_trylock(&rxnet->client_conn_discard_lock)) { |
45025bce DH |
1054 | _leave(" [already]"); |
1055 | return; | |
1056 | } | |
1057 | ||
1058 | /* We keep an estimate of what the number of conns ought to be after | |
1059 | * we've discarded some so that we don't overdo the discarding. | |
1060 | */ | |
2baec2c3 | 1061 | nr_conns = rxnet->nr_client_conns; |
45025bce DH |
1062 | |
1063 | next: | |
2baec2c3 | 1064 | spin_lock(&rxnet->client_conn_cache_lock); |
45025bce | 1065 | |
2baec2c3 | 1066 | if (list_empty(&rxnet->idle_client_conns)) |
45025bce DH |
1067 | goto out; |
1068 | ||
2baec2c3 | 1069 | conn = list_entry(rxnet->idle_client_conns.next, |
45025bce DH |
1070 | struct rxrpc_connection, cache_link); |
1071 | ASSERT(test_bit(RXRPC_CONN_EXPOSED, &conn->flags)); | |
1072 | ||
2baec2c3 | 1073 | if (!rxnet->kill_all_client_conns) { |
45025bce DH |
1074 | /* If the number of connections is over the reap limit, we |
1075 | * expedite discard by reducing the expiry timeout. We must, | |
1076 | * however, have at least a short grace period to be able to do | |
1077 | * final-ACK or ABORT retransmission. | |
1078 | */ | |
1079 | expiry = rxrpc_conn_idle_client_expiry; | |
1080 | if (nr_conns > rxrpc_reap_client_connections) | |
1081 | expiry = rxrpc_conn_idle_client_fast_expiry; | |
1082 | ||
1083 | conn_expires_at = conn->idle_timestamp + expiry; | |
1084 | ||
1085 | now = READ_ONCE(jiffies); | |
1086 | if (time_after(conn_expires_at, now)) | |
1087 | goto not_yet_expired; | |
1088 | } | |
1089 | ||
363deeab | 1090 | trace_rxrpc_client(conn, -1, rxrpc_client_discard); |
45025bce DH |
1091 | if (!test_and_clear_bit(RXRPC_CONN_EXPOSED, &conn->flags)) |
1092 | BUG(); | |
1093 | conn->cache_state = RXRPC_CONN_CLIENT_INACTIVE; | |
1094 | list_del_init(&conn->cache_link); | |
1095 | ||
2baec2c3 | 1096 | spin_unlock(&rxnet->client_conn_cache_lock); |
45025bce DH |
1097 | |
1098 | /* When we cleared the EXPOSED flag, we took on responsibility for the | |
1099 | * reference that that had on the usage count. We deal with that here. | |
1100 | * If someone re-sets the flag and re-gets the ref, that's fine. | |
1101 | */ | |
1102 | rxrpc_put_connection(conn); | |
1103 | did_discard = true; | |
1104 | nr_conns--; | |
1105 | goto next; | |
1106 | ||
1107 | not_yet_expired: | |
1108 | /* The connection at the front of the queue hasn't yet expired, so | |
1109 | * schedule the work item for that point if we discarded something. | |
1110 | * | |
1111 | * We don't worry if the work item is already scheduled - it can look | |
1112 | * after rescheduling itself at a later time. We could cancel it, but | |
1113 | * then things get messier. | |
1114 | */ | |
1115 | _debug("not yet"); | |
2baec2c3 | 1116 | if (!rxnet->kill_all_client_conns) |
45025bce | 1117 | queue_delayed_work(rxrpc_workqueue, |
2baec2c3 | 1118 | &rxnet->client_conn_reaper, |
45025bce DH |
1119 | conn_expires_at - now); |
1120 | ||
1121 | out: | |
2baec2c3 DH |
1122 | spin_unlock(&rxnet->client_conn_cache_lock); |
1123 | spin_unlock(&rxnet->client_conn_discard_lock); | |
45025bce DH |
1124 | _leave(""); |
1125 | } | |
1126 | ||
1127 | /* | |
1128 | * Preemptively destroy all the client connection records rather than waiting | |
1129 | * for them to time out | |
1130 | */ | |
2baec2c3 | 1131 | void rxrpc_destroy_all_client_connections(struct rxrpc_net *rxnet) |
45025bce DH |
1132 | { |
1133 | _enter(""); | |
1134 | ||
2baec2c3 DH |
1135 | spin_lock(&rxnet->client_conn_cache_lock); |
1136 | rxnet->kill_all_client_conns = true; | |
1137 | spin_unlock(&rxnet->client_conn_cache_lock); | |
45025bce | 1138 | |
2baec2c3 | 1139 | cancel_delayed_work(&rxnet->client_conn_reaper); |
45025bce | 1140 | |
2baec2c3 | 1141 | if (!queue_delayed_work(rxrpc_workqueue, &rxnet->client_conn_reaper, 0)) |
45025bce DH |
1142 | _debug("destroy: queue failed"); |
1143 | ||
1144 | _leave(""); | |
001c1122 | 1145 | } |