blob: 199bcc34241ba0155a367f11d05edf5d9c138a02 [file] [log] [blame]
* Berkeley style UIO structures - Alan Cox 1994.
* 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.
#ifndef __LINUX_UIO_H
#define __LINUX_UIO_H
#include <linux/kernel.h>
#include <uapi/linux/uio.h>
struct page;
struct kvec {
void *iov_base; /* and that should *never* hold a userland pointer */
size_t iov_len;
struct iov_iter {
const struct iovec *iov;
unsigned long nr_segs;
size_t iov_offset;
size_t count;
* Total number of bytes covered by an iovec.
* NOTE that it is not safe to use this function until all the iovec's
* segment lengths have been validated. Because the individual lengths can
* overflow a size_t when added together.
static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
unsigned long seg;
size_t ret = 0;
for (seg = 0; seg < nr_segs; seg++)
ret += iov[seg].iov_len;
return ret;
static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
return (struct iovec) {
.iov_base = iter->iov->iov_base + iter->iov_offset,
.iov_len = min(iter->count,
iter->iov->iov_len - iter->iov_offset),
#define iov_for_each(iov, iter, start) \
for (iter = (start); \
(iter).count && \
((iov = iov_iter_iovec(&(iter))), 1); \
iov_iter_advance(&(iter), (iov).iov_len))
unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
size_t iov_iter_copy_from_user_atomic(struct page *page,
struct iov_iter *i, unsigned long offset, size_t bytes);
size_t iov_iter_copy_from_user(struct page *page,
struct iov_iter *i, unsigned long offset, size_t bytes);
void iov_iter_advance(struct iov_iter *i, size_t bytes);
int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
size_t iov_iter_single_seg_count(const struct iov_iter *i);
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i);
static inline void iov_iter_init(struct iov_iter *i,
const struct iovec *iov, unsigned long nr_segs,
size_t count, size_t written)
i->iov = iov;
i->nr_segs = nr_segs;
i->iov_offset = 0;
i->count = count + written;
iov_iter_advance(i, written);
static inline size_t iov_iter_count(struct iov_iter *i)
return i->count;
int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len);