#include <linux/errno.h>
#include <linux/kernel.h>

static long mycounter = 0;

asmlinkage long sys_inccount(void) {
	long newcounter;
	newcounter = mycounter + 1;
	if (newcounter < 0)
		return -EINVAL;
	else
		return mycounter = newcounter;
}

asmlinkage long sys_deccount(void) {
	long newcounter;
	newcounter = mycounter - 1;
	if (newcounter < 0)
		return -EINVAL;
	else
		return mycounter = newcounter;
}

asmlinkage long sys_getcount(void) {
	return mycounter;
}

asmlinkage long sys_zerocount(void) {
	return mycounter = 0;
}