/* SPDX-License-Identifier: GPL-2.0 */
#if 1
#include <linux/init.h>
#include <linux/ioctl.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/maple_tree.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <linux/printk.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <linux/types.h>
#endif

struct maple_tree mt;

struct va {
	u64 addr;
	u64 range;
};

static int va_store(struct va *va)
{
	void *entry = NULL;
	u64 addr = va->addr;
	u64 range = va->range;
	u64 last = addr + range - 1;
	MA_STATE(mas, &mt, addr, addr);
	int ret;

	mas_lock(&mas);

	if ((entry = mas_walk(&mas))) {
		pr_err("addr=%llx, range=%llx, last=%llx, mas.index=%lx, mas.last=%lx, entry=%px - exists\n",
		       addr, range, last, mas.index, mas.last, entry);
		ret = -EEXIST;
		goto err_unlock;
	}

	if (mas.last < last) {
		pr_err("addr=%llx, range=%llx, last=%llx, mas.index=%lx, mas.last%lx, va=%px - not enough space\n",
		       addr, range, last, mas.index, mas.last, va);
		ret = -EEXIST;
		goto err_unlock;
	}

	mas.last = last;
	ret = mas_store_gfp(&mas, &va, GFP_KERNEL);
	if (ret) {
		pr_err("mas_store_gfp() failed\n");
		goto err_unlock;
	}

	mas_unlock(&mas);

	pr_info("addr=%llx, range=%llx, last=%llx, mas.index=%lx, mas.last=%lx, va=%px - insert\n",
		addr, range, last, mas.index, mas.last, va);

	return 0;

err_unlock:
	mas_unlock(&mas);
	return ret;
}

static int __init maple_init(void)
{
	struct va kernel_node = { .addr = 0xc0000, .range = 0x40000 };
	struct va node = { .addr = 0x0, .range = 0xc0000 };

	mt_init(&mt);

	va_store(&kernel_node);
	va_store(&node);

	return 0;
}

static void __exit maple_exit(void)
{
	mtree_lock(&mt);
	__mt_destroy(&mt);
	mtree_unlock(&mt);
}

module_init(maple_init);
module_exit(maple_exit);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Danilo Krummrich");
MODULE_DESCRIPTION("Maple Tree example.");
MODULE_VERSION("0.1");