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/*
* linux/mm/filemap.h
*
* Copyright (C) 1994-1999 Linus Torvalds
*/
#ifndef __FILEMAP_H
#define __FILEMAP_H
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/uio.h>
#include <linux/uaccess.h>
size_t
__filemap_copy_from_user_iovec_inatomic(char *vaddr,
const struct iovec *iov,
size_t base,
size_t bytes);
/*
* Copy as much as we can into the page and return the number of bytes which
* were sucessfully copied. If a fault is encountered then return the number of
* bytes which were copied.
*/
static inline size_t
filemap_copy_from_user_atomic(struct page *page, unsigned long offset,
const struct iovec *iov, unsigned long nr_segs,
size_t base, size_t bytes)
{
char *kaddr;
size_t copied;
kaddr = kmap_atomic(page, KM_USER0);
if (likely(nr_segs == 1)) {
int left;
char __user *buf = iov->iov_base + base;
left = __copy_from_user_inatomic_nocache(kaddr + offset,
buf, bytes);
copied = bytes - left;
} else {
copied = __filemap_copy_from_user_iovec_inatomic(kaddr + offset,
iov, base, bytes);
}
kunmap_atomic(kaddr, KM_USER0);
return copied;
}
/*
* This has the same sideeffects and return value as
* filemap_copy_from_user_atomic().
* The difference is that it attempts to resolve faults.
*/
static inline size_t
filemap_copy_from_user(struct page *page, unsigned long offset,
const struct iovec *iov, unsigned long nr_segs,
size_t base, size_t bytes)
{
char *kaddr;
size_t copied;
kaddr = kmap(page);
if (likely(nr_segs == 1)) {
int left;
char __user *buf = iov->iov_base + base;
left = __copy_from_user_nocache(kaddr + offset, buf, bytes);
copied = bytes - left;
} else {
copied = __filemap_copy_from_user_iovec_inatomic(kaddr + offset,
iov, base, bytes);
}
kunmap(page);
return copied;
}
static inline void
filemap_set_next_iovec(const struct iovec **iovp, unsigned long nr_segs,
size_t *basep, size_t bytes)
{
if (likely(nr_segs == 1)) {
*basep += bytes;
} else {
const struct iovec *iov = *iovp;
size_t base = *basep;
while (bytes) {
int copy = min(bytes, iov->iov_len - base);
bytes -= copy;
base += copy;
if (iov->iov_len == base) {
iov++;
base = 0;
}
}
*iovp = iov;
*basep = base;
}
}
#endif
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