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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 | |
716154c5 BB |
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 | 50 | atomic_set(&cvp->cv_waiters, 0); |
d2733258 | 51 | atomic_set(&cvp->cv_refs, 1); |
4efd4118 | 52 | cvp->cv_mutex = NULL; |
4efd4118 BB |
53 | |
54 | /* We may be called when there is a non-zero preempt_count or | |
55 | * interrupts are disabled is which case we must not sleep. | |
56 | */ | |
57 | if (current_thread_info()->preempt_count || irqs_disabled()) | |
58 | flags = KM_NOSLEEP; | |
59 | ||
b17edc10 | 60 | SEXIT; |
4efd4118 BB |
61 | } |
62 | EXPORT_SYMBOL(__cv_init); | |
63 | ||
d599e4fa BB |
64 | static int |
65 | cv_destroy_wakeup(kcondvar_t *cvp) | |
66 | { | |
d2733258 BB |
67 | if (!atomic_read(&cvp->cv_waiters) && !atomic_read(&cvp->cv_refs)) { |
68 | ASSERT(cvp->cv_mutex == NULL); | |
69 | ASSERT(!waitqueue_active(&cvp->cv_event)); | |
70 | return 1; | |
71 | } | |
d599e4fa | 72 | |
d2733258 | 73 | return 0; |
d599e4fa BB |
74 | } |
75 | ||
4efd4118 BB |
76 | void |
77 | __cv_destroy(kcondvar_t *cvp) | |
78 | { | |
b17edc10 | 79 | SENTRY; |
4efd4118 BB |
80 | ASSERT(cvp); |
81 | ASSERT(cvp->cv_magic == CV_MAGIC); | |
d599e4fa | 82 | |
d2733258 BB |
83 | cvp->cv_magic = CV_DESTROY; |
84 | atomic_dec(&cvp->cv_refs); | |
85 | ||
86 | /* Block until all waiters are woken and references dropped. */ | |
d599e4fa BB |
87 | while (cv_destroy_wakeup(cvp) == 0) |
88 | wait_event_timeout(cvp->cv_destroy, cv_destroy_wakeup(cvp), 1); | |
89 | ||
3c60f505 | 90 | ASSERT3P(cvp->cv_mutex, ==, NULL); |
d2733258 | 91 | ASSERT3S(atomic_read(&cvp->cv_refs), ==, 0); |
3c60f505 BB |
92 | ASSERT3S(atomic_read(&cvp->cv_waiters), ==, 0); |
93 | ASSERT3S(waitqueue_active(&cvp->cv_event), ==, 0); | |
4efd4118 | 94 | |
b17edc10 | 95 | SEXIT; |
4efd4118 BB |
96 | } |
97 | EXPORT_SYMBOL(__cv_destroy); | |
98 | ||
f752b46e BB |
99 | static void |
100 | cv_wait_common(kcondvar_t *cvp, kmutex_t *mp, int state) | |
4efd4118 BB |
101 | { |
102 | DEFINE_WAIT(wait); | |
b17edc10 | 103 | SENTRY; |
4efd4118 BB |
104 | |
105 | ASSERT(cvp); | |
106 | ASSERT(mp); | |
107 | ASSERT(cvp->cv_magic == CV_MAGIC); | |
4efd4118 | 108 | ASSERT(mutex_owned(mp)); |
d2733258 | 109 | atomic_inc(&cvp->cv_refs); |
4efd4118 BB |
110 | |
111 | if (cvp->cv_mutex == NULL) | |
112 | cvp->cv_mutex = mp; | |
113 | ||
114 | /* Ensure the same mutex is used by all callers */ | |
115 | ASSERT(cvp->cv_mutex == mp); | |
4efd4118 | 116 | |
f752b46e | 117 | prepare_to_wait_exclusive(&cvp->cv_event, &wait, state); |
4efd4118 BB |
118 | atomic_inc(&cvp->cv_waiters); |
119 | ||
120 | /* Mutex should be dropped after prepare_to_wait() this | |
121 | * ensures we're linked in to the waiters list and avoids the | |
122 | * race where 'cvp->cv_waiters > 0' but the list is empty. */ | |
123 | mutex_exit(mp); | |
124 | schedule(); | |
125 | mutex_enter(mp); | |
126 | ||
058de03c | 127 | /* No more waiters a different mutex could be used */ |
d599e4fa | 128 | if (atomic_dec_and_test(&cvp->cv_waiters)) { |
058de03c | 129 | cvp->cv_mutex = NULL; |
d599e4fa BB |
130 | wake_up(&cvp->cv_destroy); |
131 | } | |
058de03c | 132 | |
4efd4118 | 133 | finish_wait(&cvp->cv_event, &wait); |
d2733258 | 134 | atomic_dec(&cvp->cv_refs); |
d599e4fa | 135 | |
b17edc10 | 136 | SEXIT; |
4efd4118 | 137 | } |
f752b46e BB |
138 | |
139 | void | |
140 | __cv_wait(kcondvar_t *cvp, kmutex_t *mp) | |
141 | { | |
142 | cv_wait_common(cvp, mp, TASK_UNINTERRUPTIBLE); | |
143 | } | |
4efd4118 BB |
144 | EXPORT_SYMBOL(__cv_wait); |
145 | ||
f752b46e BB |
146 | void |
147 | __cv_wait_interruptible(kcondvar_t *cvp, kmutex_t *mp) | |
148 | { | |
149 | cv_wait_common(cvp, mp, TASK_INTERRUPTIBLE); | |
150 | } | |
151 | EXPORT_SYMBOL(__cv_wait_interruptible); | |
152 | ||
4efd4118 BB |
153 | /* 'expire_time' argument is an absolute wall clock time in jiffies. |
154 | * Return value is time left (expire_time - now) or -1 if timeout occurred. | |
155 | */ | |
3f688a8c NK |
156 | static clock_t |
157 | __cv_timedwait_common(kcondvar_t *cvp, kmutex_t *mp, | |
158 | clock_t expire_time, int state) | |
4efd4118 BB |
159 | { |
160 | DEFINE_WAIT(wait); | |
161 | clock_t time_left; | |
b17edc10 | 162 | SENTRY; |
4efd4118 BB |
163 | |
164 | ASSERT(cvp); | |
165 | ASSERT(mp); | |
166 | ASSERT(cvp->cv_magic == CV_MAGIC); | |
4efd4118 | 167 | ASSERT(mutex_owned(mp)); |
d2733258 | 168 | atomic_inc(&cvp->cv_refs); |
4efd4118 BB |
169 | |
170 | if (cvp->cv_mutex == NULL) | |
171 | cvp->cv_mutex = mp; | |
172 | ||
173 | /* Ensure the same mutex is used by all callers */ | |
174 | ASSERT(cvp->cv_mutex == mp); | |
4efd4118 BB |
175 | |
176 | /* XXX - Does not handle jiffie wrap properly */ | |
177 | time_left = expire_time - jiffies; | |
d2733258 BB |
178 | if (time_left <= 0) { |
179 | atomic_dec(&cvp->cv_refs); | |
b17edc10 | 180 | SRETURN(-1); |
d2733258 | 181 | } |
4efd4118 | 182 | |
3f688a8c | 183 | prepare_to_wait_exclusive(&cvp->cv_event, &wait, state); |
4efd4118 BB |
184 | atomic_inc(&cvp->cv_waiters); |
185 | ||
186 | /* Mutex should be dropped after prepare_to_wait() this | |
187 | * ensures we're linked in to the waiters list and avoids the | |
188 | * race where 'cvp->cv_waiters > 0' but the list is empty. */ | |
189 | mutex_exit(mp); | |
190 | time_left = schedule_timeout(time_left); | |
191 | mutex_enter(mp); | |
192 | ||
058de03c | 193 | /* No more waiters a different mutex could be used */ |
d599e4fa | 194 | if (atomic_dec_and_test(&cvp->cv_waiters)) { |
058de03c | 195 | cvp->cv_mutex = NULL; |
d599e4fa BB |
196 | wake_up(&cvp->cv_destroy); |
197 | } | |
058de03c | 198 | |
4efd4118 | 199 | finish_wait(&cvp->cv_event, &wait); |
d2733258 | 200 | atomic_dec(&cvp->cv_refs); |
4efd4118 | 201 | |
b17edc10 | 202 | SRETURN(time_left > 0 ? time_left : -1); |
4efd4118 | 203 | } |
3f688a8c NK |
204 | |
205 | clock_t | |
206 | __cv_timedwait(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time) | |
207 | { | |
208 | return __cv_timedwait_common(cvp, mp, exp_time, TASK_UNINTERRUPTIBLE); | |
209 | } | |
4efd4118 BB |
210 | EXPORT_SYMBOL(__cv_timedwait); |
211 | ||
3f688a8c NK |
212 | clock_t |
213 | __cv_timedwait_interruptible(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time) | |
214 | { | |
215 | return __cv_timedwait_common(cvp, mp, exp_time, TASK_INTERRUPTIBLE); | |
216 | } | |
217 | EXPORT_SYMBOL(__cv_timedwait_interruptible); | |
218 | ||
4efd4118 BB |
219 | void |
220 | __cv_signal(kcondvar_t *cvp) | |
221 | { | |
b17edc10 | 222 | SENTRY; |
4efd4118 BB |
223 | ASSERT(cvp); |
224 | ASSERT(cvp->cv_magic == CV_MAGIC); | |
d2733258 | 225 | atomic_inc(&cvp->cv_refs); |
4efd4118 BB |
226 | |
227 | /* All waiters are added with WQ_FLAG_EXCLUSIVE so only one | |
228 | * waiter will be set runable with each call to wake_up(). | |
229 | * Additionally wake_up() holds a spin_lock assoicated with | |
230 | * the wait queue to ensure we don't race waking up processes. */ | |
231 | if (atomic_read(&cvp->cv_waiters) > 0) | |
232 | wake_up(&cvp->cv_event); | |
233 | ||
d2733258 | 234 | atomic_dec(&cvp->cv_refs); |
b17edc10 | 235 | SEXIT; |
4efd4118 BB |
236 | } |
237 | EXPORT_SYMBOL(__cv_signal); | |
238 | ||
239 | void | |
240 | __cv_broadcast(kcondvar_t *cvp) | |
241 | { | |
d2733258 | 242 | SENTRY; |
4efd4118 BB |
243 | ASSERT(cvp); |
244 | ASSERT(cvp->cv_magic == CV_MAGIC); | |
d2733258 | 245 | atomic_inc(&cvp->cv_refs); |
4efd4118 BB |
246 | |
247 | /* Wake_up_all() will wake up all waiters even those which | |
248 | * have the WQ_FLAG_EXCLUSIVE flag set. */ | |
249 | if (atomic_read(&cvp->cv_waiters) > 0) | |
250 | wake_up_all(&cvp->cv_event); | |
251 | ||
d2733258 | 252 | atomic_dec(&cvp->cv_refs); |
b17edc10 | 253 | SEXIT; |
4efd4118 BB |
254 | } |
255 | EXPORT_SYMBOL(__cv_broadcast); |