linux-imx

/* file-nommu.c: no-MMU version of ramfs

 *

 * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.

 * Written by David Howells (dhowells@redhat.com)

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version

 * 2 of the License, or (at your option) any later version.

 */

​

#include <linux/module.h>

#include <linux/fs.h>

#include <linux/mm.h>

#include <linux/pagemap.h>

#include <linux/highmem.h>

#include <linux/init.h>

#include <linux/string.h>

#include <linux/backing-dev.h>

#include <linux/ramfs.h>

#include <linux/pagevec.h>

#include <linux/mman.h>

#include <linux/sched.h>

#include <linux/slab.h>

​

#include <linux/uaccess.h>

#include "internal.h"

​

static int ramfs_nommu_setattr(struct dentry *, struct iattr *);

static unsigned long ramfs_nommu_get_unmapped_area(struct file *file,

                           unsigned long addr,

                           unsigned long len,

                           unsigned long pgoff,

                           unsigned long flags);

static int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma);

​

static unsigned ramfs_mmap_capabilities(struct file *file)

{

    return NOMMU_MAP_DIRECT | NOMMU_MAP_COPY | NOMMU_MAP_READ |

        NOMMU_MAP_WRITE | NOMMU_MAP_EXEC;

}

​

const struct file_operations ramfs_file_operations = {

    .mmap_capabilities  = ramfs_mmap_capabilities,

    .mmap           = ramfs_nommu_mmap,

    .get_unmapped_area  = ramfs_nommu_get_unmapped_area,

    .read_iter      = generic_file_read_iter,

    .write_iter     = generic_file_write_iter,

    .fsync          = noop_fsync,

    .splice_read        = generic_file_splice_read,

    .splice_write       = iter_file_splice_write,

    .llseek         = generic_file_llseek,

};

​

const struct inode_operations ramfs_file_inode_operations = {

    .setattr        = ramfs_nommu_setattr,

    .getattr        = simple_getattr,

};

​

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

/*

 * add a contiguous set of pages into a ramfs inode when it's truncated from

 * size 0 on the assumption that it's going to be used for an mmap of shared

 * memory

 */

int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)

{

    unsigned long npages, xpages, loop;

    struct page *pages;

    unsigned order;

    void *data;

    int ret;

    gfp_t gfp = mapping_gfp_mask(inode->i_mapping);

​

    /* make various checks */

    order = get_order(newsize);

    if (unlikely(order >= MAX_ORDER))

        return -EFBIG;

​

    ret = inode_newsize_ok(inode, newsize);

    if (ret)

        return ret;

​

    i_size_write(inode, newsize);

​

    /* allocate enough contiguous pages to be able to satisfy the

     * request */

    pages = alloc_pages(gfp, order);

    if (!pages)

        return -ENOMEM;

​

    /* split the high-order page into an array of single pages */