2002-07-09 16:24:59 +04:00
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/* Mutex and recursive_lock code */
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/*
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** Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
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** Distributed under the terms of the NewOS License.
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*/
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#include <kernel.h>
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#include <OS.h>
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#include <lock.h>
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#include <debug.h>
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#include <arch/cpu.h>
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#include <Errors.h>
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#include <atomic.h>
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#include <thread.h>
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int recursive_lock_get_recursion(recursive_lock *lock)
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{
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thread_id thid = thread_get_current_thread_id();
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if(lock->holder == thid) {
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return lock->recursion;
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} else {
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return -1;
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}
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}
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int recursive_lock_create(recursive_lock *lock)
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{
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if(lock == NULL)
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2002-07-12 02:21:56 +04:00
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return EINVAL;
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2002-07-09 16:24:59 +04:00
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lock->holder = -1;
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lock->recursion = 0;
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lock->sem = create_sem(1, "recursive_lock_sem");
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// if(lock->sem < 0)
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// return -1;
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return B_NO_ERROR;
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}
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void recursive_lock_destroy(recursive_lock *lock)
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{
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if(lock == NULL)
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return;
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if(lock->sem > 0)
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delete_sem(lock->sem);
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lock->sem = -1;
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}
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bool recursive_lock_lock(recursive_lock *lock)
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{
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thread_id thid = thread_get_current_thread_id();
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bool retval = false;
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if(thid != lock->holder) {
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acquire_sem(lock->sem);
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lock->holder = thid;
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retval = true;
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}
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lock->recursion++;
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return retval;
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}
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bool recursive_lock_unlock(recursive_lock *lock)
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{
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thread_id thid = thread_get_current_thread_id();
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bool retval = false;
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if(thid != lock->holder)
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panic("recursive_lock %p unlocked by non-holder thread!\n", lock);
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if(--lock->recursion == 0) {
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lock->holder = -1;
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release_sem(lock->sem);
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retval = true;
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}
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return retval;
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}
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int mutex_init(mutex *m, const char *in_name)
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{
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const char *name;
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if(m == NULL)
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2002-07-12 02:21:56 +04:00
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return EINVAL;
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2002-07-09 16:24:59 +04:00
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if(in_name == NULL)
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name = "mutex_sem";
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else
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name = in_name;
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m->count = 0;
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m->sem = create_sem(0, name);
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if(m->sem < 0)
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return m->sem;
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return 0;
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}
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void mutex_destroy(mutex *m)
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{
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if(m == NULL)
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return;
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if(m->sem >= 0) {
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delete_sem(m->sem);
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}
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}
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void mutex_lock(mutex *m)
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{
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if(atomic_add(&m->count, 1) >= 1)
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acquire_sem(m->sem);
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}
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void mutex_unlock(mutex *m)
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{
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if(atomic_add(&m->count, -1) > 1)
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release_sem(m->sem);
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}
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