seq_lock.c

是关于linux2.5.1的完全源码

/*
 *  Do sleep inside a spin-lock
 *  Copyright (c) 1999 by Takashi Iwai <[e-mail]>
 *
 *
 *   This program 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.
 *
 *   This program 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 this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#define __NO_VERSION__
#include <sound/driver.h>
#include <sound/core.h>
#include "seq_lock.h"

#if defined(__SMP__) || defined(CONFIG_SND_DEBUG)

/* (interruptible) sleep_on during the specified spinlock */
void snd_seq_sleep_in_lock(wait_queue_head_t *p, spinlock_t *lock)
{
	wait_queue_t wait;

	set_current_state(TASK_INTERRUPTIBLE);
	init_waitqueue_entry(&wait, current);

	add_wait_queue(p, &wait);

	spin_unlock(lock);
	schedule();
	spin_lock_irq(lock);

	remove_wait_queue(p, &wait);
}

/* (interruptible) sleep_on with timeout during the specified spinlock */
long snd_seq_sleep_timeout_in_lock(wait_queue_head_t *p, spinlock_t *lock, long timeout)
{
	wait_queue_t wait;

	set_current_state(TASK_INTERRUPTIBLE);
	init_waitqueue_entry(&wait, current);

	add_wait_queue(p, &wait);

	spin_unlock(lock);
	timeout = schedule_timeout(timeout);
	spin_lock_irq(lock);

	remove_wait_queue(p, &wait);

	return timeout;
}

/* wait until all locks are released */
void snd_use_lock_sync_helper(snd_use_lock_t *lockp, const char *file, int line)
{
	int max_count = 5 * HZ;

	if (atomic_read(lockp) < 0) {
		printk(KERN_WARNING "seq_lock: lock trouble [counter = %d] in %s:%d\n", atomic_read(lockp), file, line);
		return;
	}
	while (atomic_read(lockp) > 0) {
		if (max_count == 0) {
			snd_printk(KERN_WARNING "seq_lock: timeout [%d left] in %s:%d\n", atomic_read(lockp), file, line);
			break;
		}
		set_current_state(TASK_UNINTERRUPTIBLE);
		schedule_timeout(1);
		max_count--;
	}
}

#endif