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>.
8 * This file is part of the SPL, Solaris Porting Layer.
9 * For details, see <http://github.com/behlendorf/spl/>.
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.
16 * The SPL is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
21 * You should have received a copy of the GNU General Public License along
22 * with the SPL. If not, see <http://www.gnu.org/licenses/>.
23 *****************************************************************************
24 * Solaris Porting Layer (SPL) Credential Implementation.
25 \*****************************************************************************/
27 #include <sys/condvar.h>
28 #include <spl-debug.h>
30 #ifdef SS_DEBUG_SUBSYS
31 #undef SS_DEBUG_SUBSYS
34 #define SS_DEBUG_SUBSYS SS_CONDVAR
37 __cv_init(kcondvar_t
*cvp
, char *name
, kcv_type_t type
, void *arg
)
44 ASSERT(type
== CV_DEFAULT
);
47 cvp
->cv_magic
= CV_MAGIC
;
48 init_waitqueue_head(&cvp
->cv_event
);
49 init_waitqueue_head(&cvp
->cv_destroy
);
50 atomic_set(&cvp
->cv_waiters
, 0);
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.
56 if (current_thread_info()->preempt_count
|| irqs_disabled())
61 EXPORT_SYMBOL(__cv_init
);
64 cv_destroy_wakeup(kcondvar_t
*cvp
)
66 if ((waitqueue_active(&cvp
->cv_event
)) ||
67 (atomic_read(&cvp
->cv_waiters
) > 0))
74 __cv_destroy(kcondvar_t
*cvp
)
78 ASSERT(cvp
->cv_magic
== CV_MAGIC
);
80 /* Block until all waiters have woken */
81 while (cv_destroy_wakeup(cvp
) == 0)
82 wait_event_timeout(cvp
->cv_destroy
, cv_destroy_wakeup(cvp
), 1);
84 ASSERT(cvp
->cv_mutex
== NULL
);
85 ASSERT(atomic_read(&cvp
->cv_waiters
) == 0);
86 ASSERT(!waitqueue_active(&cvp
->cv_event
));
90 EXPORT_SYMBOL(__cv_destroy
);
93 cv_wait_common(kcondvar_t
*cvp
, kmutex_t
*mp
, int state
)
100 ASSERT(cvp
->cv_magic
== CV_MAGIC
);
101 ASSERT(mutex_owned(mp
));
103 if (cvp
->cv_mutex
== NULL
)
106 /* Ensure the same mutex is used by all callers */
107 ASSERT(cvp
->cv_mutex
== mp
);
109 prepare_to_wait_exclusive(&cvp
->cv_event
, &wait
, state
);
110 atomic_inc(&cvp
->cv_waiters
);
112 /* Mutex should be dropped after prepare_to_wait() this
113 * ensures we're linked in to the waiters list and avoids the
114 * race where 'cvp->cv_waiters > 0' but the list is empty. */
119 /* No more waiters a different mutex could be used */
120 if (atomic_dec_and_test(&cvp
->cv_waiters
)) {
121 cvp
->cv_mutex
= NULL
;
122 wake_up(&cvp
->cv_destroy
);
125 finish_wait(&cvp
->cv_event
, &wait
);
131 __cv_wait(kcondvar_t
*cvp
, kmutex_t
*mp
)
133 cv_wait_common(cvp
, mp
, TASK_UNINTERRUPTIBLE
);
135 EXPORT_SYMBOL(__cv_wait
);
138 __cv_wait_interruptible(kcondvar_t
*cvp
, kmutex_t
*mp
)
140 cv_wait_common(cvp
, mp
, TASK_INTERRUPTIBLE
);
142 EXPORT_SYMBOL(__cv_wait_interruptible
);
144 /* 'expire_time' argument is an absolute wall clock time in jiffies.
145 * Return value is time left (expire_time - now) or -1 if timeout occurred.
148 __cv_timedwait_common(kcondvar_t
*cvp
, kmutex_t
*mp
,
149 clock_t expire_time
, int state
)
157 ASSERT(cvp
->cv_magic
== CV_MAGIC
);
158 ASSERT(mutex_owned(mp
));
160 if (cvp
->cv_mutex
== NULL
)
163 /* Ensure the same mutex is used by all callers */
164 ASSERT(cvp
->cv_mutex
== mp
);
166 /* XXX - Does not handle jiffie wrap properly */
167 time_left
= expire_time
- jiffies
;
171 prepare_to_wait_exclusive(&cvp
->cv_event
, &wait
, state
);
172 atomic_inc(&cvp
->cv_waiters
);
174 /* Mutex should be dropped after prepare_to_wait() this
175 * ensures we're linked in to the waiters list and avoids the
176 * race where 'cvp->cv_waiters > 0' but the list is empty. */
178 time_left
= schedule_timeout(time_left
);
181 /* No more waiters a different mutex could be used */
182 if (atomic_dec_and_test(&cvp
->cv_waiters
)) {
183 cvp
->cv_mutex
= NULL
;
184 wake_up(&cvp
->cv_destroy
);
187 finish_wait(&cvp
->cv_event
, &wait
);
189 SRETURN(time_left
> 0 ? time_left
: -1);
193 __cv_timedwait(kcondvar_t
*cvp
, kmutex_t
*mp
, clock_t exp_time
)
195 return __cv_timedwait_common(cvp
, mp
, exp_time
, TASK_UNINTERRUPTIBLE
);
197 EXPORT_SYMBOL(__cv_timedwait
);
200 __cv_timedwait_interruptible(kcondvar_t
*cvp
, kmutex_t
*mp
, clock_t exp_time
)
202 return __cv_timedwait_common(cvp
, mp
, exp_time
, TASK_INTERRUPTIBLE
);
204 EXPORT_SYMBOL(__cv_timedwait_interruptible
);
207 __cv_signal(kcondvar_t
*cvp
)
211 ASSERT(cvp
->cv_magic
== CV_MAGIC
);
213 /* All waiters are added with WQ_FLAG_EXCLUSIVE so only one
214 * waiter will be set runable with each call to wake_up().
215 * Additionally wake_up() holds a spin_lock assoicated with
216 * the wait queue to ensure we don't race waking up processes. */
217 if (atomic_read(&cvp
->cv_waiters
) > 0)
218 wake_up(&cvp
->cv_event
);
222 EXPORT_SYMBOL(__cv_signal
);
225 __cv_broadcast(kcondvar_t
*cvp
)
228 ASSERT(cvp
->cv_magic
== CV_MAGIC
);
231 /* Wake_up_all() will wake up all waiters even those which
232 * have the WQ_FLAG_EXCLUSIVE flag set. */
233 if (atomic_read(&cvp
->cv_waiters
) > 0)
234 wake_up_all(&cvp
->cv_event
);
238 EXPORT_SYMBOL(__cv_broadcast
);