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 atomic_set(&cvp->cv_waiters, 0);
52 cvp->cv_name_size = strlen(name) + 1;
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.
57 if (current_thread_info()->preempt_count || irqs_disabled())
60 cvp->cv_name = kmem_alloc(cvp->cv_name_size, flags);
62 strcpy(cvp->cv_name, name);
66 EXPORT_SYMBOL(__cv_init);
69 __cv_destroy(kcondvar_t *cvp)
73 ASSERT(cvp->cv_magic == CV_MAGIC);
74 ASSERT(cvp->cv_mutex == NULL);
75 ASSERT(atomic_read(&cvp->cv_waiters) == 0);
76 ASSERT(!waitqueue_active(&cvp->cv_event));
79 kmem_free(cvp->cv_name, cvp->cv_name_size);
81 ASSERT3P(memset(cvp, CV_POISON, sizeof(*cvp)), ==, cvp);
84 EXPORT_SYMBOL(__cv_destroy);
87 cv_wait_common(kcondvar_t *cvp, kmutex_t *mp, int state)
94 ASSERT(cvp->cv_magic == CV_MAGIC);
95 ASSERT(mutex_owned(mp));
97 if (cvp->cv_mutex == NULL)
100 /* Ensure the same mutex is used by all callers */
101 ASSERT(cvp->cv_mutex == mp);
103 prepare_to_wait_exclusive(&cvp->cv_event, &wait, state);
104 atomic_inc(&cvp->cv_waiters);
106 /* Mutex should be dropped after prepare_to_wait() this
107 * ensures we're linked in to the waiters list and avoids the
108 * race where 'cvp->cv_waiters > 0' but the list is empty. */
113 /* No more waiters a different mutex could be used */
114 if (atomic_dec_and_test(&cvp->cv_waiters))
115 cvp->cv_mutex = NULL;
117 finish_wait(&cvp->cv_event, &wait);
122 __cv_wait(kcondvar_t *cvp, kmutex_t *mp)
124 cv_wait_common(cvp, mp, TASK_UNINTERRUPTIBLE);
126 EXPORT_SYMBOL(__cv_wait);
129 __cv_wait_interruptible(kcondvar_t *cvp, kmutex_t *mp)
131 cv_wait_common(cvp, mp, TASK_INTERRUPTIBLE);
133 EXPORT_SYMBOL(__cv_wait_interruptible);
135 /* 'expire_time' argument is an absolute wall clock time in jiffies.
136 * Return value is time left (expire_time - now) or -1 if timeout occurred.
139 __cv_timedwait(kcondvar_t *cvp, kmutex_t *mp, clock_t expire_time)
147 ASSERT(cvp->cv_magic == CV_MAGIC);
148 ASSERT(mutex_owned(mp));
150 if (cvp->cv_mutex == NULL)
153 /* Ensure the same mutex is used by all callers */
154 ASSERT(cvp->cv_mutex == mp);
156 /* XXX - Does not handle jiffie wrap properly */
157 time_left = expire_time - jiffies;
161 prepare_to_wait_exclusive(&cvp->cv_event, &wait,
162 TASK_UNINTERRUPTIBLE);
163 atomic_inc(&cvp->cv_waiters);
165 /* Mutex should be dropped after prepare_to_wait() this
166 * ensures we're linked in to the waiters list and avoids the
167 * race where 'cvp->cv_waiters > 0' but the list is empty. */
169 time_left = schedule_timeout(time_left);
172 /* No more waiters a different mutex could be used */
173 if (atomic_dec_and_test(&cvp->cv_waiters))
174 cvp->cv_mutex = NULL;
176 finish_wait(&cvp->cv_event, &wait);
178 SRETURN(time_left > 0 ? time_left : -1);
180 EXPORT_SYMBOL(__cv_timedwait);
183 __cv_signal(kcondvar_t *cvp)
187 ASSERT(cvp->cv_magic == CV_MAGIC);
189 /* All waiters are added with WQ_FLAG_EXCLUSIVE so only one
190 * waiter will be set runable with each call to wake_up().
191 * Additionally wake_up() holds a spin_lock assoicated with
192 * the wait queue to ensure we don't race waking up processes. */
193 if (atomic_read(&cvp->cv_waiters) > 0)
194 wake_up(&cvp->cv_event);
198 EXPORT_SYMBOL(__cv_signal);
201 __cv_broadcast(kcondvar_t *cvp)
204 ASSERT(cvp->cv_magic == CV_MAGIC);
207 /* Wake_up_all() will wake up all waiters even those which
208 * have the WQ_FLAG_EXCLUSIVE flag set. */
209 if (atomic_read(&cvp->cv_waiters) > 0)
210 wake_up_all(&cvp->cv_event);
214 EXPORT_SYMBOL(__cv_broadcast);