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1da177e4 LT |
1 | /* krxtimod.c: RXRPC timeout daemon |
2 | * | |
3 | * Copyright (C) 2002 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 License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/sched.h> | |
15 | #include <linux/completion.h> | |
16 | #include <rxrpc/rxrpc.h> | |
17 | #include <rxrpc/krxtimod.h> | |
18 | #include <asm/errno.h> | |
19 | #include "internal.h" | |
20 | ||
21 | static DECLARE_COMPLETION(krxtimod_alive); | |
22 | static DECLARE_COMPLETION(krxtimod_dead); | |
23 | static DECLARE_WAIT_QUEUE_HEAD(krxtimod_sleepq); | |
24 | static int krxtimod_die; | |
25 | ||
26 | static LIST_HEAD(krxtimod_list); | |
27 | static DEFINE_SPINLOCK(krxtimod_lock); | |
28 | ||
29 | static int krxtimod(void *arg); | |
30 | ||
31 | /*****************************************************************************/ | |
32 | /* | |
33 | * start the timeout daemon | |
34 | */ | |
35 | int rxrpc_krxtimod_start(void) | |
36 | { | |
37 | int ret; | |
38 | ||
39 | ret = kernel_thread(krxtimod, NULL, 0); | |
40 | if (ret < 0) | |
41 | return ret; | |
42 | ||
43 | wait_for_completion(&krxtimod_alive); | |
44 | ||
45 | return ret; | |
46 | } /* end rxrpc_krxtimod_start() */ | |
47 | ||
48 | /*****************************************************************************/ | |
49 | /* | |
50 | * stop the timeout daemon | |
51 | */ | |
52 | void rxrpc_krxtimod_kill(void) | |
53 | { | |
54 | /* get rid of my daemon */ | |
55 | krxtimod_die = 1; | |
56 | wake_up(&krxtimod_sleepq); | |
57 | wait_for_completion(&krxtimod_dead); | |
58 | ||
59 | } /* end rxrpc_krxtimod_kill() */ | |
60 | ||
61 | /*****************************************************************************/ | |
62 | /* | |
63 | * timeout processing daemon | |
64 | */ | |
65 | static int krxtimod(void *arg) | |
66 | { | |
67 | DECLARE_WAITQUEUE(myself, current); | |
68 | ||
69 | rxrpc_timer_t *timer; | |
70 | ||
71 | printk("Started krxtimod %d\n", current->pid); | |
72 | ||
73 | daemonize("krxtimod"); | |
74 | ||
75 | complete(&krxtimod_alive); | |
76 | ||
77 | /* loop around looking for things to attend to */ | |
78 | loop: | |
79 | set_current_state(TASK_INTERRUPTIBLE); | |
80 | add_wait_queue(&krxtimod_sleepq, &myself); | |
81 | ||
82 | for (;;) { | |
83 | unsigned long jif; | |
a8fc3d8d | 84 | long timeout; |
1da177e4 LT |
85 | |
86 | /* deal with the server being asked to die */ | |
87 | if (krxtimod_die) { | |
88 | remove_wait_queue(&krxtimod_sleepq, &myself); | |
89 | _leave(""); | |
90 | complete_and_exit(&krxtimod_dead, 0); | |
91 | } | |
92 | ||
3e1d1d28 | 93 | try_to_freeze(); |
1da177e4 LT |
94 | |
95 | /* discard pending signals */ | |
96 | rxrpc_discard_my_signals(); | |
97 | ||
98 | /* work out the time to elapse before the next event */ | |
99 | spin_lock(&krxtimod_lock); | |
100 | if (list_empty(&krxtimod_list)) { | |
101 | timeout = MAX_SCHEDULE_TIMEOUT; | |
102 | } | |
103 | else { | |
104 | timer = list_entry(krxtimod_list.next, | |
105 | rxrpc_timer_t, link); | |
106 | timeout = timer->timo_jif; | |
107 | jif = jiffies; | |
108 | ||
109 | if (time_before_eq((unsigned long) timeout, jif)) | |
110 | goto immediate; | |
111 | ||
112 | else { | |
113 | timeout = (long) timeout - (long) jiffies; | |
114 | } | |
115 | } | |
116 | spin_unlock(&krxtimod_lock); | |
117 | ||
118 | schedule_timeout(timeout); | |
119 | ||
120 | set_current_state(TASK_INTERRUPTIBLE); | |
121 | } | |
122 | ||
123 | /* the thing on the front of the queue needs processing | |
124 | * - we come here with the lock held and timer pointing to the expired | |
125 | * entry | |
126 | */ | |
127 | immediate: | |
128 | remove_wait_queue(&krxtimod_sleepq, &myself); | |
129 | set_current_state(TASK_RUNNING); | |
130 | ||
131 | _debug("@@@ Begin Timeout of %p", timer); | |
132 | ||
133 | /* dequeue the timer */ | |
134 | list_del_init(&timer->link); | |
135 | spin_unlock(&krxtimod_lock); | |
136 | ||
137 | /* call the timeout function */ | |
138 | timer->ops->timed_out(timer); | |
139 | ||
140 | _debug("@@@ End Timeout"); | |
141 | goto loop; | |
142 | ||
143 | } /* end krxtimod() */ | |
144 | ||
145 | /*****************************************************************************/ | |
146 | /* | |
147 | * (re-)queue a timer | |
148 | */ | |
149 | void rxrpc_krxtimod_add_timer(rxrpc_timer_t *timer, unsigned long timeout) | |
150 | { | |
151 | struct list_head *_p; | |
152 | rxrpc_timer_t *ptimer; | |
153 | ||
154 | _enter("%p,%lu", timer, timeout); | |
155 | ||
156 | spin_lock(&krxtimod_lock); | |
157 | ||
158 | list_del(&timer->link); | |
159 | ||
160 | /* the timer was deferred or reset - put it back in the queue at the | |
161 | * right place */ | |
162 | timer->timo_jif = jiffies + timeout; | |
163 | ||
164 | list_for_each(_p, &krxtimod_list) { | |
165 | ptimer = list_entry(_p, rxrpc_timer_t, link); | |
166 | if (time_before(timer->timo_jif, ptimer->timo_jif)) | |
167 | break; | |
168 | } | |
169 | ||
170 | list_add_tail(&timer->link, _p); /* insert before stopping point */ | |
171 | ||
172 | spin_unlock(&krxtimod_lock); | |
173 | ||
174 | wake_up(&krxtimod_sleepq); | |
175 | ||
176 | _leave(""); | |
177 | } /* end rxrpc_krxtimod_add_timer() */ | |
178 | ||
179 | /*****************************************************************************/ | |
180 | /* | |
181 | * dequeue a timer | |
182 | * - returns 0 if the timer was deleted or -ENOENT if it wasn't queued | |
183 | */ | |
184 | int rxrpc_krxtimod_del_timer(rxrpc_timer_t *timer) | |
185 | { | |
186 | int ret = 0; | |
187 | ||
188 | _enter("%p", timer); | |
189 | ||
190 | spin_lock(&krxtimod_lock); | |
191 | ||
192 | if (list_empty(&timer->link)) | |
193 | ret = -ENOENT; | |
194 | else | |
195 | list_del_init(&timer->link); | |
196 | ||
197 | spin_unlock(&krxtimod_lock); | |
198 | ||
199 | wake_up(&krxtimod_sleepq); | |
200 | ||
201 | _leave(" = %d", ret); | |
202 | return ret; | |
203 | } /* end rxrpc_krxtimod_del_timer() */ |