mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-29 14:05:19 +08:00
08adb7dabd
... and do the same on the compat side of things. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
138 lines
3.1 KiB
C
138 lines
3.1 KiB
C
/*
|
|
* iovec manipulation routines.
|
|
*
|
|
*
|
|
* 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.
|
|
*
|
|
* Fixes:
|
|
* Andrew Lunn : Errors in iovec copying.
|
|
* Pedro Roque : Added memcpy_fromiovecend and
|
|
* csum_..._fromiovecend.
|
|
* Andi Kleen : fixed error handling for 2.1
|
|
* Alexey Kuznetsov: 2.1 optimisations
|
|
* Andi Kleen : Fix csum*fromiovecend for IPv6.
|
|
*/
|
|
|
|
#include <linux/errno.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/net.h>
|
|
#include <linux/in6.h>
|
|
#include <asm/uaccess.h>
|
|
#include <asm/byteorder.h>
|
|
#include <net/checksum.h>
|
|
#include <net/sock.h>
|
|
|
|
/*
|
|
* And now for the all-in-one: copy and checksum from a user iovec
|
|
* directly to a datagram
|
|
* Calls to csum_partial but the last must be in 32 bit chunks
|
|
*
|
|
* ip_build_xmit must ensure that when fragmenting only the last
|
|
* call to this function will be unaligned also.
|
|
*/
|
|
int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov,
|
|
int offset, unsigned int len, __wsum *csump)
|
|
{
|
|
__wsum csum = *csump;
|
|
int partial_cnt = 0, err = 0;
|
|
|
|
/* Skip over the finished iovecs */
|
|
while (offset >= iov->iov_len) {
|
|
offset -= iov->iov_len;
|
|
iov++;
|
|
}
|
|
|
|
while (len > 0) {
|
|
u8 __user *base = iov->iov_base + offset;
|
|
int copy = min_t(unsigned int, len, iov->iov_len - offset);
|
|
|
|
offset = 0;
|
|
|
|
/* There is a remnant from previous iov. */
|
|
if (partial_cnt) {
|
|
int par_len = 4 - partial_cnt;
|
|
|
|
/* iov component is too short ... */
|
|
if (par_len > copy) {
|
|
if (copy_from_user(kdata, base, copy))
|
|
goto out_fault;
|
|
kdata += copy;
|
|
base += copy;
|
|
partial_cnt += copy;
|
|
len -= copy;
|
|
iov++;
|
|
if (len)
|
|
continue;
|
|
*csump = csum_partial(kdata - partial_cnt,
|
|
partial_cnt, csum);
|
|
goto out;
|
|
}
|
|
if (copy_from_user(kdata, base, par_len))
|
|
goto out_fault;
|
|
csum = csum_partial(kdata - partial_cnt, 4, csum);
|
|
kdata += par_len;
|
|
base += par_len;
|
|
copy -= par_len;
|
|
len -= par_len;
|
|
partial_cnt = 0;
|
|
}
|
|
|
|
if (len > copy) {
|
|
partial_cnt = copy % 4;
|
|
if (partial_cnt) {
|
|
copy -= partial_cnt;
|
|
if (copy_from_user(kdata + copy, base + copy,
|
|
partial_cnt))
|
|
goto out_fault;
|
|
}
|
|
}
|
|
|
|
if (copy) {
|
|
csum = csum_and_copy_from_user(base, kdata, copy,
|
|
csum, &err);
|
|
if (err)
|
|
goto out;
|
|
}
|
|
len -= copy + partial_cnt;
|
|
kdata += copy + partial_cnt;
|
|
iov++;
|
|
}
|
|
*csump = csum;
|
|
out:
|
|
return err;
|
|
|
|
out_fault:
|
|
err = -EFAULT;
|
|
goto out;
|
|
}
|
|
EXPORT_SYMBOL(csum_partial_copy_fromiovecend);
|
|
|
|
unsigned long iov_pages(const struct iovec *iov, int offset,
|
|
unsigned long nr_segs)
|
|
{
|
|
unsigned long seg, base;
|
|
int pages = 0, len, size;
|
|
|
|
while (nr_segs && (offset >= iov->iov_len)) {
|
|
offset -= iov->iov_len;
|
|
++iov;
|
|
--nr_segs;
|
|
}
|
|
|
|
for (seg = 0; seg < nr_segs; seg++) {
|
|
base = (unsigned long)iov[seg].iov_base + offset;
|
|
len = iov[seg].iov_len - offset;
|
|
size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
|
|
pages += size;
|
|
offset = 0;
|
|
}
|
|
|
|
return pages;
|
|
}
|
|
EXPORT_SYMBOL(iov_pages);
|