/*****************************************************************************\ * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC. * Copyright (C) 2007 The Regents of the University of California. * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER). * Written by Brian Behlendorf . * UCRL-CODE-235197 * * This file is part of the SPL, Solaris Porting Layer. * For details, see . * * The SPL is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. * * The SPL is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * for more details. * * You should have received a copy of the GNU General Public License along * with the SPL. If not, see . ***************************************************************************** * Solaris Porting Layer (SPL) Credential Implementation. \*****************************************************************************/ #include #include #ifdef SS_DEBUG_SUBSYS #undef SS_DEBUG_SUBSYS #endif #define SS_DEBUG_SUBSYS SS_CONDVAR void __cv_init(kcondvar_t *cvp, char *name, kcv_type_t type, void *arg) { int flags = KM_SLEEP; SENTRY; ASSERT(cvp); ASSERT(name == NULL); ASSERT(type == CV_DEFAULT); ASSERT(arg == NULL); cvp->cv_magic = CV_MAGIC; init_waitqueue_head(&cvp->cv_event); init_waitqueue_head(&cvp->cv_destroy); atomic_set(&cvp->cv_waiters, 0); atomic_set(&cvp->cv_refs, 1); cvp->cv_mutex = NULL; /* We may be called when there is a non-zero preempt_count or * interrupts are disabled is which case we must not sleep. */ if (current_thread_info()->preempt_count || irqs_disabled()) flags = KM_NOSLEEP; SEXIT; } EXPORT_SYMBOL(__cv_init); static int cv_destroy_wakeup(kcondvar_t *cvp) { if (!atomic_read(&cvp->cv_waiters) && !atomic_read(&cvp->cv_refs)) { ASSERT(cvp->cv_mutex == NULL); ASSERT(!waitqueue_active(&cvp->cv_event)); return 1; } return 0; } void __cv_destroy(kcondvar_t *cvp) { SENTRY; ASSERT(cvp); ASSERT(cvp->cv_magic == CV_MAGIC); cvp->cv_magic = CV_DESTROY; atomic_dec(&cvp->cv_refs); /* Block until all waiters are woken and references dropped. */ while (cv_destroy_wakeup(cvp) == 0) wait_event_timeout(cvp->cv_destroy, cv_destroy_wakeup(cvp), 1); ASSERT3P(cvp->cv_mutex, ==, NULL); ASSERT3S(atomic_read(&cvp->cv_refs), ==, 0); ASSERT3S(atomic_read(&cvp->cv_waiters), ==, 0); ASSERT3S(waitqueue_active(&cvp->cv_event), ==, 0); SEXIT; } EXPORT_SYMBOL(__cv_destroy); static void cv_wait_common(kcondvar_t *cvp, kmutex_t *mp, int state, int io) { DEFINE_WAIT(wait); SENTRY; ASSERT(cvp); ASSERT(mp); ASSERT(cvp->cv_magic == CV_MAGIC); ASSERT(mutex_owned(mp)); atomic_inc(&cvp->cv_refs); if (cvp->cv_mutex == NULL) cvp->cv_mutex = mp; /* Ensure the same mutex is used by all callers */ ASSERT(cvp->cv_mutex == mp); prepare_to_wait_exclusive(&cvp->cv_event, &wait, state); atomic_inc(&cvp->cv_waiters); /* Mutex should be dropped after prepare_to_wait() this * ensures we're linked in to the waiters list and avoids the * race where 'cvp->cv_waiters > 0' but the list is empty. */ mutex_exit(mp); if (io) io_schedule(); else schedule(); mutex_enter(mp); /* No more waiters a different mutex could be used */ if (atomic_dec_and_test(&cvp->cv_waiters)) { cvp->cv_mutex = NULL; wake_up(&cvp->cv_destroy); } finish_wait(&cvp->cv_event, &wait); atomic_dec(&cvp->cv_refs); SEXIT; } void __cv_wait(kcondvar_t *cvp, kmutex_t *mp) { cv_wait_common(cvp, mp, TASK_UNINTERRUPTIBLE, 0); } EXPORT_SYMBOL(__cv_wait); void __cv_wait_interruptible(kcondvar_t *cvp, kmutex_t *mp) { cv_wait_common(cvp, mp, TASK_INTERRUPTIBLE, 0); } EXPORT_SYMBOL(__cv_wait_interruptible); void __cv_wait_io(kcondvar_t *cvp, kmutex_t *mp) { cv_wait_common(cvp, mp, TASK_UNINTERRUPTIBLE, 1); } EXPORT_SYMBOL(__cv_wait_io); /* 'expire_time' argument is an absolute wall clock time in jiffies. * Return value is time left (expire_time - now) or -1 if timeout occurred. */ static clock_t __cv_timedwait_common(kcondvar_t *cvp, kmutex_t *mp, clock_t expire_time, int state) { DEFINE_WAIT(wait); clock_t time_left; SENTRY; ASSERT(cvp); ASSERT(mp); ASSERT(cvp->cv_magic == CV_MAGIC); ASSERT(mutex_owned(mp)); atomic_inc(&cvp->cv_refs); if (cvp->cv_mutex == NULL) cvp->cv_mutex = mp; /* Ensure the same mutex is used by all callers */ ASSERT(cvp->cv_mutex == mp); /* XXX - Does not handle jiffie wrap properly */ time_left = expire_time - jiffies; if (time_left <= 0) { atomic_dec(&cvp->cv_refs); SRETURN(-1); } prepare_to_wait_exclusive(&cvp->cv_event, &wait, state); atomic_inc(&cvp->cv_waiters); /* Mutex should be dropped after prepare_to_wait() this * ensures we're linked in to the waiters list and avoids the * race where 'cvp->cv_waiters > 0' but the list is empty. */ mutex_exit(mp); time_left = schedule_timeout(time_left); mutex_enter(mp); /* No more waiters a different mutex could be used */ if (atomic_dec_and_test(&cvp->cv_waiters)) { cvp->cv_mutex = NULL; wake_up(&cvp->cv_destroy); } finish_wait(&cvp->cv_event, &wait); atomic_dec(&cvp->cv_refs); SRETURN(time_left > 0 ? time_left : -1); } clock_t __cv_timedwait(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time) { return __cv_timedwait_common(cvp, mp, exp_time, TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL(__cv_timedwait); clock_t __cv_timedwait_interruptible(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time) { return __cv_timedwait_common(cvp, mp, exp_time, TASK_INTERRUPTIBLE); } EXPORT_SYMBOL(__cv_timedwait_interruptible); void __cv_signal(kcondvar_t *cvp) { SENTRY; ASSERT(cvp); ASSERT(cvp->cv_magic == CV_MAGIC); atomic_inc(&cvp->cv_refs); /* All waiters are added with WQ_FLAG_EXCLUSIVE so only one * waiter will be set runable with each call to wake_up(). * Additionally wake_up() holds a spin_lock assoicated with * the wait queue to ensure we don't race waking up processes. */ if (atomic_read(&cvp->cv_waiters) > 0) wake_up(&cvp->cv_event); atomic_dec(&cvp->cv_refs); SEXIT; } EXPORT_SYMBOL(__cv_signal); void __cv_broadcast(kcondvar_t *cvp) { SENTRY; ASSERT(cvp); ASSERT(cvp->cv_magic == CV_MAGIC); atomic_inc(&cvp->cv_refs); /* Wake_up_all() will wake up all waiters even those which * have the WQ_FLAG_EXCLUSIVE flag set. */ if (atomic_read(&cvp->cv_waiters) > 0) wake_up_all(&cvp->cv_event); atomic_dec(&cvp->cv_refs); SEXIT; } EXPORT_SYMBOL(__cv_broadcast);