[linux-2.6-block.git] / drivers / tty / tty_mutex.c

#include <linux/tty.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/semaphore.h>
#include <linux/sched.h>

/*
 * The 'big tty mutex'
 *
 * This mutex is taken and released by tty_lock() and tty_unlock(),
 * replacing the older big kernel lock.
 * It can no longer be taken recursively, and does not get
 * released implicitly while sleeping.
 *
 * Don't use in new code.
 */
static DEFINE_MUTEX(big_tty_mutex);
struct task_struct *__big_tty_mutex_owner;
EXPORT_SYMBOL_GPL(__big_tty_mutex_owner);

/*
 * Getting the big tty mutex.
 */
void __lockfunc tty_lock(void)
{
	struct task_struct *task = current;

	WARN_ON(__big_tty_mutex_owner == task);

	mutex_lock(&big_tty_mutex);
	__big_tty_mutex_owner = task;
}
EXPORT_SYMBOL(tty_lock);

void __lockfunc tty_unlock(void)
{
	struct task_struct *task = current;

	WARN_ON(__big_tty_mutex_owner != task);
	__big_tty_mutex_owner = NULL;

	mutex_unlock(&big_tty_mutex);
}
EXPORT_SYMBOL(tty_unlock);
Commit	Line	Data
b07471fa AB	1	#include <linux/tty.h>
	2	#include <linux/module.h>
	3	#include <linux/kallsyms.h>
	4	#include <linux/semaphore.h>
	5	#include <linux/sched.h>
	6
	7	/*
	8	* The 'big tty mutex'
	9	*
	10	* This mutex is taken and released by tty_lock() and tty_unlock(),
	11	* replacing the older big kernel lock.
	12	* It can no longer be taken recursively, and does not get
	13	* released implicitly while sleeping.
	14	*
	15	* Don't use in new code.
	16	*/
	17	static DEFINE_MUTEX(big_tty_mutex);
	18	struct task_struct *__big_tty_mutex_owner;
	19	EXPORT_SYMBOL_GPL(__big_tty_mutex_owner);
	20
	21	/*
	22	* Getting the big tty mutex.
	23	*/
	24	void __lockfunc tty_lock(void)
	25	{
	26	struct task_struct *task = current;
	27
	28	WARN_ON(__big_tty_mutex_owner == task);
	29
	30	mutex_lock(&big_tty_mutex);
	31	__big_tty_mutex_owner = task;
	32	}
	33	EXPORT_SYMBOL(tty_lock);
	34
	35	void __lockfunc tty_unlock(void)
	36	{
	37	struct task_struct *task = current;
	38
	39	WARN_ON(__big_tty_mutex_owner != task);
	40	__big_tty_mutex_owner = NULL;
	41
	42	mutex_unlock(&big_tty_mutex);
	43	}
	44	EXPORT_SYMBOL(tty_unlock);