// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/io_uring.h>

#include <uapi/linux/fadvise.h>
#include <uapi/linux/io_uring.h>

#include "io_uring.h"
#include "advise.h"

struct io_fadvise {
	struct file			*file;
	u64				offset;
	u32				len;
	u32				advice;
};

struct io_madvise {
	struct file			*file;
	u64				addr;
	u32				len;
	u32				advice;
};

int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
	struct io_madvise *ma = io_kiocb_to_cmd(req, struct io_madvise);

	if (sqe->buf_index || sqe->off || sqe->splice_fd_in)
		return -EINVAL;

	ma->addr = READ_ONCE(sqe->addr);
	ma->len = READ_ONCE(sqe->len);
	ma->advice = READ_ONCE(sqe->fadvise_advice);
	return 0;
#else
	return -EOPNOTSUPP;
#endif
}

int io_madvise(struct io_kiocb *req, unsigned int issue_flags)
{
#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
	struct io_madvise *ma = io_kiocb_to_cmd(req, struct io_madvise);
	int ret;

	if (issue_flags & IO_URING_F_NONBLOCK)
		return -EAGAIN;

	ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice);
	io_req_set_res(req, ret, 0);
	return IOU_OK;
#else
	return -EOPNOTSUPP;
#endif
}

int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
	struct io_fadvise *fa = io_kiocb_to_cmd(req, struct io_fadvise);

	if (sqe->buf_index || sqe->addr || sqe->splice_fd_in)
		return -EINVAL;

	fa->offset = READ_ONCE(sqe->off);
	fa->len = READ_ONCE(sqe->len);
	fa->advice = READ_ONCE(sqe->fadvise_advice);
	return 0;
}

int io_fadvise(struct io_kiocb *req, unsigned int issue_flags)
{
	struct io_fadvise *fa = io_kiocb_to_cmd(req, struct io_fadvise);
	int ret;

	if (issue_flags & IO_URING_F_NONBLOCK) {
		switch (fa->advice) {
		case POSIX_FADV_NORMAL:
		case POSIX_FADV_RANDOM:
		case POSIX_FADV_SEQUENTIAL:
			break;
		default:
			return -EAGAIN;
		}
	}

	ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice);
	if (ret < 0)
		req_set_fail(req);
	io_req_set_res(req, ret, 0);
	return IOU_OK;
}