linux-imx

// SPDX-License-Identifier: GPL-2.0 OR MIT

​

/******************************************************************************

 * privcmd-buf.c

 *

 * Mmap of hypercall buffers.

 *

 * Copyright (c) 2018 Juergen Gross

 */

​

#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt

​

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/list.h>

#include <linux/miscdevice.h>

#include <linux/mm.h>

#include <linux/slab.h>

​

#include "privcmd.h"

​

MODULE_LICENSE("GPL");

​

struct privcmd_buf_private {

    struct mutex lock;

    struct list_head list;

};

​

struct privcmd_buf_vma_private {

    struct privcmd_buf_private *file_priv;

    struct list_head list;

    unsigned int users;

    unsigned int n_pages;

    struct page *pages[];

};

​

static int privcmd_buf_open(struct inode *ino, struct file *file)

{

    struct privcmd_buf_private *file_priv;

​

    file_priv = kzalloc(sizeof(*file_priv), GFP_KERNEL);

    if (!file_priv)

        return -ENOMEM;

​

    mutex_init(&file_priv->lock);

    INIT_LIST_HEAD(&file_priv->list);

​

    file->private_data = file_priv;

​

    return 0;

}

​

static void privcmd_buf_vmapriv_free(struct privcmd_buf_vma_private *vma_priv)

{

    unsigned int i;

​

    list_del(&vma_priv->list);

​

    for (i = 0; i < vma_priv->n_pages; i++)

        __free_page(vma_priv->pages[i]);

​

    kfree(vma_priv);

}