#define __NO_VERSION__
#include <linux/config.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/personality.h>
#include <linux/smp_lock.h>
#include <linux/delay.h>

struct proc_dir_entry *rwsem_proc;

struct rw_semaphore rwsem_sem;

static int rwsem_write_proc(struct file *file, const char *buffer, unsigned long count, void *data)
{
	printk("[%05d %08x]: downing\n",current->pid,rwsem_sem.count);
	down_write(&rwsem_sem);
	printk("[%05d %08x]: downed\n",current->pid,rwsem_sem.count);
	mdelay(1);
	printk("[%05d %08x]: upping\n",current->pid,rwsem_sem.count);
	up_write(&rwsem_sem);
	printk("[%05d %08x]: upped\n",current->pid,rwsem_sem.count);

	mdelay(100);

	printk("[%05d %08x]: downing\n",current->pid,rwsem_sem.count);
	down_write(&rwsem_sem);
	printk("[%05d %08x]: downed\n",current->pid,rwsem_sem.count);
	mdelay(1);
	printk("[%05d %08x]: upping\n",current->pid,rwsem_sem.count);
	up_write(&rwsem_sem);
	printk("[%05d %08x]: upped\n",current->pid,rwsem_sem.count);

	return -ENOENT;
}

static int __init rwsem_init_module(void)
{
	printk(KERN_INFO "rwsem loading...\n");

	init_rwsem(&rwsem_sem);

	/* try and create the access point */
	rwsem_proc = create_proc_entry("rwsem",S_IRUGO|S_IWUGO,NULL);
	if (!rwsem_proc)
		return -EEXIST;

	rwsem_proc->write_proc = &rwsem_write_proc;
	return 0;
}

static void __exit rwsem_cleanup_module(void)
{
	printk(KERN_INFO "rwsem unloading\n");

	remove_proc_entry("rwsem",NULL);

}

module_init(rwsem_init_module);
module_exit(rwsem_cleanup_module);