timers.c

Minix3.11的源码。[MINIX 3是一个为高可靠性应用而设计的自由且简洁的类UNIX系统。]

/* FS timers library
 */

#include "fs.h"

#include <timers.h>
#include <minix/syslib.h>
#include <minix/com.h>

PRIVATE timer_t *fs_timers = NULL;

PUBLIC void fs_set_timer(timer_t *tp, int ticks, tmr_func_t watchdog, int arg)
{
	int r;
	clock_t now, old_head = 0, new_head;

	if ((r = getuptime(&now)) != OK)
		panic(__FILE__, "FS couldn't get uptime from system task.", NO_NUM);

	tmr_arg(tp)->ta_int = arg;

	old_head = tmrs_settimer(&fs_timers, tp, now+ticks, watchdog, &new_head);

	/* reschedule our synchronous alarm if necessary */
	if (!old_head || old_head > new_head) {
		if (sys_setalarm(new_head, 1) != OK)
			panic(__FILE__, "FS set timer "
			"couldn't set synchronous alarm.", NO_NUM);
	}

	return;
}

PUBLIC void fs_expire_timers(clock_t now)
{
	clock_t new_head;
	tmrs_exptimers(&fs_timers, now, &new_head);
	if (new_head > 0) {
		if (sys_setalarm(new_head, 1) != OK)
			panic(__FILE__, "FS expire timer couldn't set "
				"synchronous alarm.", NO_NUM);
	}
}

PUBLIC void fs_init_timer(timer_t *tp)
{
	tmr_inittimer(tp);
}

PUBLIC void fs_cancel_timer(timer_t *tp)
{
	clock_t new_head, old_head;
	old_head = tmrs_clrtimer(&fs_timers, tp, &new_head);

	/* if the earliest timer has been removed, we have to set
	 * the synalarm to the next timer, or cancel the synalarm
	 * altogether if th last time has been cancelled (new_head
	 * will be 0 then).
	 */
	if (old_head < new_head || !new_head) {
		if (sys_setalarm(new_head, 1) != OK)
			panic(__FILE__,
			"FS expire timer couldn't set synchronous alarm.",
				 NO_NUM);
	}
}