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/*
* linux/mm/filemap_xip.c
*
* Copyright (C) 2005 IBM Corporation
* Author: Carsten Otte <cotte@de.ibm.com>
*
* derived from linux/mm/filemap.c - Copyright (C) Linus Torvalds
*
*/
#include <linux/fs.h>
#include <linux/backing-dev.h>
#include <linux/pagemap.h>
#include <linux/export.h>
#include <linux/uio.h>
#include <linux/rmap.h>
#include <linux/mmu_notifier.h>
#include <linux/sched.h>
#include <linux/seqlock.h>
#include <linux/mutex.h>
#include <linux/gfp.h>
#include <asm/tlbflush.h>
#include <asm/io.h>
/*
* truncate a page used for execute in place
* functionality is analog to block_truncate_page but does use get_xip_mem
* to get the page instead of page cache
*/
int
xip_truncate_page(struct address_space *mapping, loff_t from)
{
pgoff_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
unsigned blocksize;
unsigned length;
void *xip_mem;
unsigned long xip_pfn;
int err;
BUG_ON(!mapping->a_ops->get_xip_mem);
blocksize = 1 << mapping->host->i_blkbits;
length = offset & (blocksize - 1);
/* Block boundary? Nothing to do */
if (!length)
return 0;
length = blocksize - length;
err = mapping->a_ops->get_xip_mem(mapping, index, 0,
&xip_mem, &xip_pfn);
if (unlikely(err)) {
if (err == -ENODATA)
/* Hole? No need to truncate */
return 0;
else
return err;
}
memset(xip_mem + offset, 0, length);
return 0;
}
EXPORT_SYMBOL_GPL(xip_truncate_page);
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