1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/highmem.h>
 3#include <linux/crash_dump.h>
 4#include <linux/uio.h>
 5
 6ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,
 7			 size_t csize, unsigned long offset)
 8{
 9	void  *vaddr;
10
11	if (!csize)
12		return 0;
13
14	vaddr = kmap_local_pfn(pfn);
15	csize = copy_to_iter(vaddr + offset, csize, iter);
16	kunmap_local(vaddr);
17
18	return csize;
19}