linux-imx

/*

 * linux/mm/process_vm_access.c

 *

 * Copyright (C) 2010-2011 Christopher Yeoh <cyeoh@au1.ibm.com>, IBM Corp.

 *

 * 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/mm.h>

#include <linux/uio.h>

#include <linux/sched.h>

#include <linux/sched/mm.h>

#include <linux/highmem.h>

#include <linux/ptrace.h>

#include <linux/slab.h>

#include <linux/syscalls.h>

​

#ifdef CONFIG_COMPAT

#include <linux/compat.h>

#endif

​

/**

 * process_vm_rw_pages - read/write pages from task specified

 * @pages: array of pointers to pages we want to copy

 * @offset: offset in page to start copying from/to

 * @len: number of bytes to copy

 * @iter: where to copy to/from locally

 * @vm_write: 0 means copy from, 1 means copy to

 * Returns 0 on success, error code otherwise

 */

static int process_vm_rw_pages(struct page **pages,

                   unsigned offset,

                   size_t len,

                   struct iov_iter *iter,

                   int vm_write)

{

    /* Do the copy for each page */

    while (len && iov_iter_count(iter)) {

        struct page *page = *pages++;

        size_t copy = PAGE_SIZE - offset;

        size_t copied;

​

        if (copy > len)

            copy = len;

​

        if (vm_write) {

            copied = copy_page_from_iter(page, offset, copy, iter);

            set_page_dirty_lock(page);

        } else {

            copied = copy_page_to_iter(page, offset, copy, iter);

        }

        len -= copied;

        if (copied < copy && iov_iter_count(iter))

            return -EFAULT;

        offset = 0;

    }

    return 0;

}

​

/* Maximum number of pages kmalloc'd to hold struct page's during copy */