/*
 * Copyright (c) 2005 Topspin Communications.  All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *	copyright notice, this list of conditions and the following
 *	disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *	copyright notice, this list of conditions and the following
 *	disclaimer in the documentation and/or other materials
 *	provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * $Id: $
 */
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/poll.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/cdev.h>
#include <linux/devfs_fs_kernel.h>

#include <asm/uaccess.h>
#include <asm/highmem.h>

	
MODULE_AUTHOR("Libor Michalek");
MODULE_DESCRIPTION("Get pages test");
MODULE_LICENSE("GPL");

enum {
	TEST_MAJOR = 232,
	TEST_MINOR = 255
};

#define TEST_DEV MKDEV(TEST_MAJOR, TEST_MINOR)

enum {
	TEST_CMD_REGISTER   = 1,
	TEST_CMD_UNREGISTER = 2,
	TEST_CMD_CHECK      = 3
};

struct ioctl_arg {
	__u64 addr;
	__u64 size;
};

struct region_root {
	struct semaphore mutex;
	struct list_head regions; /* list of pending events. */
	struct file *filp;
	int nr_region;
};

struct test_region {
	unsigned long user;
	unsigned long addr;
	unsigned long size;
	int  nr_pages;
	struct page **pages;
	struct region_root *root;
	struct list_head region_list; /* member in root region list */
};

static void test_unlock(struct test_region *region)
{
        long i;

	list_del(&region->region_list);

        for (i = 0; i < region->nr_pages; i++)
                put_page(region->pages[i]);

	printk(KERN_ERR "TEST: Unlocked address <%016lx>\n", region->user);

	kfree(region->pages);
	kfree(region);
}

static struct test_region *test_lookup(struct region_root *root,
				       unsigned long addr)
{
	struct test_region *region;

	list_for_each_entry(region, &root->regions, region_list)
		if (region->user == addr)
			return region;

	return NULL;
}

static int test_lock(struct region_root *root,
		     unsigned long uaddr,
		     unsigned long size)
{
	struct test_region *region;
	int nr_pages;
	int result;

	region = kmalloc(sizeof(*region), GFP_KERNEL);
	if (!region)
		return -ENOMEM;

	region->user = uaddr;
	region->addr = uaddr & PAGE_MASK;
	region->size = PAGE_ALIGN(size + (uaddr & ~PAGE_MASK));
	region->root = root;

        nr_pages = (region->size + PAGE_SIZE-1) >> PAGE_SHIFT;

	region->pages = kmalloc(sizeof(struct page *) * nr_pages, GFP_KERNEL);
	if (!region->pages) {

		result = -ENOMEM;
		goto page_err;
	}

        region->nr_pages = get_user_pages(current, current->mm,
					  region->addr,
					  nr_pages,
					  1, 0, 
					  region->pages, NULL);
	if (region->nr_pages != nr_pages) {
		result = -EFAULT;
		goto get_err;
	}

	list_add_tail(&region->region_list, &root->regions);

	printk(KERN_ERR "TEST:   Locked address <%016lx>\n", region->user);

	return 0;
get_err:
	kfree(region->pages);
page_err:
	kfree(region);
	return result;
}

static int test_check(struct test_region *region)
{
	struct page **pages;
	int nr_pages;
	int result = 0;
	int i;

	pages = kmalloc(sizeof(struct page *) * region->nr_pages, GFP_KERNEL);
	if (!pages)
		return -ENOMEM;

        nr_pages = get_user_pages(current, current->mm,
				  region->addr,
				  region->nr_pages,
				  1, 0, 
				  pages, NULL);
	if (region->nr_pages != nr_pages) {
		result = -EFAULT;
		goto get_err;
	}

	for (i = 0; i < nr_pages; i++) {

		if (region->pages[i] != pages[i])
			printk(KERN_ERR "TEST: Check error <%p:%p> "
			       "page <%u> of <%u>\n",
			       pages[i], region->pages[i], i, nr_pages);
		put_page(pages[i]);
	}

get_err:
	kfree(pages);
	return result;
}

static long test_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
	struct region_root *root = filp->private_data;
	struct test_region *region;
	struct ioctl_arg    ureq;
	int result = 0;

	if (!root)
		return -EINVAL;

        if (copy_from_user(&ureq, (void __user *)arg, sizeof(ureq)))
                return -EFAULT;

	down(&root->mutex);

	switch (cmd) {
	case TEST_CMD_REGISTER:

		result = test_lock(root, ureq.addr, ureq.size);
		break;
	case TEST_CMD_UNREGISTER:

		region = test_lookup(root, ureq.addr);
		if (!region)
			result = -ENOENT;
		else
			test_unlock(region);

		break;
	case TEST_CMD_CHECK:

		region = test_lookup(root, ureq.addr);
		if (!region)
			result = -ENOENT;
		else
			result = test_check(region);

		break;
	default:
		result = -ERANGE;
		break;
	}

	up(&root->mutex);
	return result;
}

static int test_open(struct inode *inode, struct file *filp)
{
	struct region_root *root;

	root = kmalloc(sizeof(*root), GFP_KERNEL);
	if (!root)
		return -ENOMEM;

	memset(root, 0, sizeof(*root));

	INIT_LIST_HEAD(&root->regions);
	init_MUTEX(&root->mutex);

	filp->private_data = root;
	root->filp = filp;

	printk(KERN_ERR "TEST: Created root struct\n");

	return 0;
}

static int test_close(struct inode *inode, struct file *filp)
{
	struct region_root *root = filp->private_data;
	struct test_region *region;

	down(&root->mutex);

	while (!list_empty(&root->regions)) {

		region = list_entry(root->regions.next,
				    struct test_region, region_list);
		test_unlock(region);
	}

	up(&root->mutex);

	kfree(root);

	filp->private_data = NULL;

	printk(KERN_ERR "TEST: Deleted root struct\n");
	return 0;
}

static struct file_operations test_fops = {
	.owner          = THIS_MODULE,
	.open 	        = test_open,
	.release        = test_close,
	.compat_ioctl   = test_ioctl,
	.unlocked_ioctl = test_ioctl,
};


static struct cdev test_cdev;

static int __init test_init(void)
{
	int result;

	result = register_chrdev_region(TEST_DEV, 1, "mltest");
	if (result) {
		printk(KERN_ERR "TEST: Error <%d> registering dev\n", result);
		goto err_chr;
	}

	cdev_init(&test_cdev, &test_fops);

	result = cdev_add(&test_cdev, TEST_DEV, 1);
	if (result) {
		printk(KERN_ERR "TEST: Error <%d> adding cdev\n", result);
		goto err_cdev;
	}

	return 0;
err_cdev:
	unregister_chrdev_region(TEST_DEV, 1);
err_chr:
	return result;
}

static void __exit test_cleanup(void)
{
	cdev_del(&test_cdev);
	unregister_chrdev_region(TEST_DEV, 1);
}

module_init(test_init);
module_exit(test_cleanup);