// 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;
        u64                             len;
        u32                             advice;
};

struct io_madvise {
        struct file                     *file;
        u64                             addr;
        u64                             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->splice_fd_in)
                return -EINVAL;

        ma->addr = READ_ONCE(sqe->addr);
        ma->len = READ_ONCE(sqe->off);
        if (!ma->len)
                ma->len = READ_ONCE(sqe->len);
        ma->advice = READ_ONCE(sqe->fadvise_advice);
        req->flags |= REQ_F_FORCE_ASYNC;
        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;

        WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK);

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

static bool io_fadvise_force_async(struct io_fadvise *fa)
{
        switch (fa->advice) {
        case POSIX_FADV_NORMAL:
        case POSIX_FADV_RANDOM:
        case POSIX_FADV_SEQUENTIAL:
                return false;
        default:
                return true;
        }
}

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->splice_fd_in)
                return -EINVAL;

        fa->offset = READ_ONCE(sqe->off);
        fa->len = READ_ONCE(sqe->addr);
        if (!fa->len)
                fa->len = READ_ONCE(sqe->len);
        fa->advice = READ_ONCE(sqe->fadvise_advice);
        if (io_fadvise_force_async(fa))
                req->flags |= REQ_F_FORCE_ASYNC;
        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;

        WARN_ON_ONCE(issue_flags & IO_URING_F_NONBLOCK && io_fadvise_force_async(fa));

        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_COMPLETE;
}