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1 | /*****************************************************************************\ |
2 | * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC. | |
3 | * Copyright (C) 2007 The Regents of the University of California. | |
4 | * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER). | |
5 | * Written by Brian Behlendorf <behlendorf1@llnl.gov>. | |
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6 | * UCRL-CODE-235197 |
7 | * | |
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8 | * This file is part of the SPL, Solaris Porting Layer. |
9 | * For details, see <http://github.com/behlendorf/spl/>. | |
10 | * | |
11 | * The SPL is free software; you can redistribute it and/or modify it | |
12 | * under the terms of the GNU General Public License as published by the | |
13 | * Free Software Foundation; either version 2 of the License, or (at your | |
14 | * option) any later version. | |
715f6251 | 15 | * |
716154c5 | 16 | * The SPL is distributed in the hope that it will be useful, but WITHOUT |
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17 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
18 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
19 | * for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU General Public License along | |
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22 | * with the SPL. If not, see <http://www.gnu.org/licenses/>. |
23 | ***************************************************************************** | |
24 | * Solaris Porting Layer (SPL) Credential Implementation. | |
25 | \*****************************************************************************/ | |
715f6251 | 26 | |
4efd4118 | 27 | #include <sys/condvar.h> |
55abb092 | 28 | #include <spl-debug.h> |
4efd4118 | 29 | |
b17edc10 BB |
30 | #ifdef SS_DEBUG_SUBSYS |
31 | #undef SS_DEBUG_SUBSYS | |
4efd4118 BB |
32 | #endif |
33 | ||
b17edc10 | 34 | #define SS_DEBUG_SUBSYS SS_CONDVAR |
4efd4118 BB |
35 | |
36 | void | |
37 | __cv_init(kcondvar_t *cvp, char *name, kcv_type_t type, void *arg) | |
38 | { | |
39 | int flags = KM_SLEEP; | |
40 | ||
b17edc10 | 41 | SENTRY; |
4efd4118 | 42 | ASSERT(cvp); |
b29012b9 | 43 | ASSERT(name == NULL); |
4efd4118 BB |
44 | ASSERT(type == CV_DEFAULT); |
45 | ASSERT(arg == NULL); | |
46 | ||
47 | cvp->cv_magic = CV_MAGIC; | |
48 | init_waitqueue_head(&cvp->cv_event); | |
d599e4fa | 49 | init_waitqueue_head(&cvp->cv_destroy); |
4efd4118 BB |
50 | atomic_set(&cvp->cv_waiters, 0); |
51 | cvp->cv_mutex = NULL; | |
4efd4118 BB |
52 | |
53 | /* We may be called when there is a non-zero preempt_count or | |
54 | * interrupts are disabled is which case we must not sleep. | |
55 | */ | |
56 | if (current_thread_info()->preempt_count || irqs_disabled()) | |
57 | flags = KM_NOSLEEP; | |
58 | ||
b17edc10 | 59 | SEXIT; |
4efd4118 BB |
60 | } |
61 | EXPORT_SYMBOL(__cv_init); | |
62 | ||
d599e4fa BB |
63 | static int |
64 | cv_destroy_wakeup(kcondvar_t *cvp) | |
65 | { | |
3c60f505 BB |
66 | if ((cvp->cv_mutex != NULL) || |
67 | (waitqueue_active(&cvp->cv_event)) || | |
d599e4fa BB |
68 | (atomic_read(&cvp->cv_waiters) > 0)) |
69 | return 0; | |
70 | ||
71 | return 1; | |
72 | } | |
73 | ||
4efd4118 BB |
74 | void |
75 | __cv_destroy(kcondvar_t *cvp) | |
76 | { | |
b17edc10 | 77 | SENTRY; |
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78 | ASSERT(cvp); |
79 | ASSERT(cvp->cv_magic == CV_MAGIC); | |
d599e4fa BB |
80 | |
81 | /* Block until all waiters have woken */ | |
82 | while (cv_destroy_wakeup(cvp) == 0) | |
83 | wait_event_timeout(cvp->cv_destroy, cv_destroy_wakeup(cvp), 1); | |
84 | ||
3c60f505 BB |
85 | ASSERT3P(cvp->cv_mutex, ==, NULL); |
86 | ASSERT3S(atomic_read(&cvp->cv_waiters), ==, 0); | |
87 | ASSERT3S(waitqueue_active(&cvp->cv_event), ==, 0); | |
4efd4118 | 88 | |
b17edc10 | 89 | SEXIT; |
4efd4118 BB |
90 | } |
91 | EXPORT_SYMBOL(__cv_destroy); | |
92 | ||
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93 | static void |
94 | cv_wait_common(kcondvar_t *cvp, kmutex_t *mp, int state) | |
4efd4118 BB |
95 | { |
96 | DEFINE_WAIT(wait); | |
b17edc10 | 97 | SENTRY; |
4efd4118 BB |
98 | |
99 | ASSERT(cvp); | |
100 | ASSERT(mp); | |
101 | ASSERT(cvp->cv_magic == CV_MAGIC); | |
4efd4118 BB |
102 | ASSERT(mutex_owned(mp)); |
103 | ||
104 | if (cvp->cv_mutex == NULL) | |
105 | cvp->cv_mutex = mp; | |
106 | ||
107 | /* Ensure the same mutex is used by all callers */ | |
108 | ASSERT(cvp->cv_mutex == mp); | |
4efd4118 | 109 | |
f752b46e | 110 | prepare_to_wait_exclusive(&cvp->cv_event, &wait, state); |
4efd4118 BB |
111 | atomic_inc(&cvp->cv_waiters); |
112 | ||
113 | /* Mutex should be dropped after prepare_to_wait() this | |
114 | * ensures we're linked in to the waiters list and avoids the | |
115 | * race where 'cvp->cv_waiters > 0' but the list is empty. */ | |
116 | mutex_exit(mp); | |
117 | schedule(); | |
118 | mutex_enter(mp); | |
119 | ||
058de03c | 120 | /* No more waiters a different mutex could be used */ |
d599e4fa | 121 | if (atomic_dec_and_test(&cvp->cv_waiters)) { |
058de03c | 122 | cvp->cv_mutex = NULL; |
d599e4fa BB |
123 | wake_up(&cvp->cv_destroy); |
124 | } | |
058de03c | 125 | |
4efd4118 | 126 | finish_wait(&cvp->cv_event, &wait); |
d599e4fa | 127 | |
b17edc10 | 128 | SEXIT; |
4efd4118 | 129 | } |
f752b46e BB |
130 | |
131 | void | |
132 | __cv_wait(kcondvar_t *cvp, kmutex_t *mp) | |
133 | { | |
134 | cv_wait_common(cvp, mp, TASK_UNINTERRUPTIBLE); | |
135 | } | |
4efd4118 BB |
136 | EXPORT_SYMBOL(__cv_wait); |
137 | ||
f752b46e BB |
138 | void |
139 | __cv_wait_interruptible(kcondvar_t *cvp, kmutex_t *mp) | |
140 | { | |
141 | cv_wait_common(cvp, mp, TASK_INTERRUPTIBLE); | |
142 | } | |
143 | EXPORT_SYMBOL(__cv_wait_interruptible); | |
144 | ||
4efd4118 BB |
145 | /* 'expire_time' argument is an absolute wall clock time in jiffies. |
146 | * Return value is time left (expire_time - now) or -1 if timeout occurred. | |
147 | */ | |
3f688a8c NK |
148 | static clock_t |
149 | __cv_timedwait_common(kcondvar_t *cvp, kmutex_t *mp, | |
150 | clock_t expire_time, int state) | |
4efd4118 BB |
151 | { |
152 | DEFINE_WAIT(wait); | |
153 | clock_t time_left; | |
b17edc10 | 154 | SENTRY; |
4efd4118 BB |
155 | |
156 | ASSERT(cvp); | |
157 | ASSERT(mp); | |
158 | ASSERT(cvp->cv_magic == CV_MAGIC); | |
4efd4118 BB |
159 | ASSERT(mutex_owned(mp)); |
160 | ||
161 | if (cvp->cv_mutex == NULL) | |
162 | cvp->cv_mutex = mp; | |
163 | ||
164 | /* Ensure the same mutex is used by all callers */ | |
165 | ASSERT(cvp->cv_mutex == mp); | |
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166 | |
167 | /* XXX - Does not handle jiffie wrap properly */ | |
168 | time_left = expire_time - jiffies; | |
169 | if (time_left <= 0) | |
b17edc10 | 170 | SRETURN(-1); |
4efd4118 | 171 | |
3f688a8c | 172 | prepare_to_wait_exclusive(&cvp->cv_event, &wait, state); |
4efd4118 BB |
173 | atomic_inc(&cvp->cv_waiters); |
174 | ||
175 | /* Mutex should be dropped after prepare_to_wait() this | |
176 | * ensures we're linked in to the waiters list and avoids the | |
177 | * race where 'cvp->cv_waiters > 0' but the list is empty. */ | |
178 | mutex_exit(mp); | |
179 | time_left = schedule_timeout(time_left); | |
180 | mutex_enter(mp); | |
181 | ||
058de03c | 182 | /* No more waiters a different mutex could be used */ |
d599e4fa | 183 | if (atomic_dec_and_test(&cvp->cv_waiters)) { |
058de03c | 184 | cvp->cv_mutex = NULL; |
d599e4fa BB |
185 | wake_up(&cvp->cv_destroy); |
186 | } | |
058de03c | 187 | |
4efd4118 BB |
188 | finish_wait(&cvp->cv_event, &wait); |
189 | ||
b17edc10 | 190 | SRETURN(time_left > 0 ? time_left : -1); |
4efd4118 | 191 | } |
3f688a8c NK |
192 | |
193 | clock_t | |
194 | __cv_timedwait(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time) | |
195 | { | |
196 | return __cv_timedwait_common(cvp, mp, exp_time, TASK_UNINTERRUPTIBLE); | |
197 | } | |
4efd4118 BB |
198 | EXPORT_SYMBOL(__cv_timedwait); |
199 | ||
3f688a8c NK |
200 | clock_t |
201 | __cv_timedwait_interruptible(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time) | |
202 | { | |
203 | return __cv_timedwait_common(cvp, mp, exp_time, TASK_INTERRUPTIBLE); | |
204 | } | |
205 | EXPORT_SYMBOL(__cv_timedwait_interruptible); | |
206 | ||
4efd4118 BB |
207 | void |
208 | __cv_signal(kcondvar_t *cvp) | |
209 | { | |
b17edc10 | 210 | SENTRY; |
4efd4118 BB |
211 | ASSERT(cvp); |
212 | ASSERT(cvp->cv_magic == CV_MAGIC); | |
213 | ||
214 | /* All waiters are added with WQ_FLAG_EXCLUSIVE so only one | |
215 | * waiter will be set runable with each call to wake_up(). | |
216 | * Additionally wake_up() holds a spin_lock assoicated with | |
217 | * the wait queue to ensure we don't race waking up processes. */ | |
218 | if (atomic_read(&cvp->cv_waiters) > 0) | |
219 | wake_up(&cvp->cv_event); | |
220 | ||
b17edc10 | 221 | SEXIT; |
4efd4118 BB |
222 | } |
223 | EXPORT_SYMBOL(__cv_signal); | |
224 | ||
225 | void | |
226 | __cv_broadcast(kcondvar_t *cvp) | |
227 | { | |
228 | ASSERT(cvp); | |
229 | ASSERT(cvp->cv_magic == CV_MAGIC); | |
b17edc10 | 230 | SENTRY; |
4efd4118 BB |
231 | |
232 | /* Wake_up_all() will wake up all waiters even those which | |
233 | * have the WQ_FLAG_EXCLUSIVE flag set. */ | |
234 | if (atomic_read(&cvp->cv_waiters) > 0) | |
235 | wake_up_all(&cvp->cv_event); | |
236 | ||
b17edc10 | 237 | SEXIT; |
4efd4118 BB |
238 | } |
239 | EXPORT_SYMBOL(__cv_broadcast); |