/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */
/*
* University Copyright- Copyright (c) 1982, 1986, 1988
* The Regents of the University of California
* All Rights Reserved
*
* University Acknowledgment- Portions of this document are derived from
* software developed by the University of California, Berkeley, and its
* contributors.
*/
/*
* Copyright (c) 2015 by Chunwei Chen. All rights reserved.
*/
#ifdef _KERNEL
#include <sys/types.h>
#include <sys/uio_impl.h>
#include <sys/sysmacros.h>
#include <sys/strings.h>
#include <linux/kmap_compat.h>
#include <linux/uaccess.h>
/*
* Move "n" bytes at byte address "p"; "rw" indicates the direction
* of the move, and the I/O parameters are provided in "uio", which is
* update to reflect the data which was moved. Returns 0 on success or
* a non-zero errno on failure.
*/
static int
uiomove_iov(void *p, size_t n, enum uio_rw rw, struct uio *uio)
{
const struct iovec *iov = uio->uio_iov;
size_t skip = uio->uio_skip;
ulong_t cnt;
while (n && uio->uio_resid) {
cnt = MIN(iov->iov_len - skip, n);
switch (uio->uio_segflg) {
case UIO_USERSPACE:
/*
* p = kernel data pointer
* iov->iov_base = user data pointer
*/
if (rw == UIO_READ) {
if (copy_to_user(iov->iov_base+skip, p, cnt))
return (EFAULT);
} else {
unsigned long b_left = 0;
if (uio->uio_fault_disable) {
if (!zfs_access_ok(VERIFY_READ,
(iov->iov_base + skip), cnt)) {
return (EFAULT);
}
pagefault_disable();
b_left =
__copy_from_user_inatomic(p,
(iov->iov_base + skip), cnt);
pagefault_enable();
} else {
b_left =
copy_from_user(p,
(iov->iov_base + skip), cnt);
}
if (b_left > 0) {
unsigned long c_bytes =
cnt - b_left;
uio->uio_skip += c_bytes;
ASSERT3U(uio->uio_skip, <,
iov->iov_len);
uio->uio_resid -= c_bytes;
uio->uio_loffset += c_bytes;
return (EFAULT);
}
}
break;
case UIO_SYSSPACE:
if (rw == UIO_READ)
bcopy(p, iov->iov_base + skip, cnt);
else
bcopy(iov->iov_base + skip, p, cnt);
break;
default:
ASSERT(0);
}
skip += cnt;
if (skip == iov->iov_len) {
skip = 0;
uio->uio_iov = (++iov);
uio->uio_iovcnt--;
}
uio->uio_skip = skip;
uio->uio_resid -= cnt;
uio->uio_loffset += cnt;
p = (caddr_t)p + cnt;
n -= cnt;
}
return (0);
}
static int
uiomove_bvec(void *p, size_t n, enum uio_rw rw, struct uio *uio)
{
const struct bio_vec *bv = uio->uio_bvec;
size_t skip = uio->uio_skip;
ulong_t cnt;
while (n && uio->uio_resid) {
void *paddr;
cnt = MIN(bv->bv_len - skip, n);
paddr = zfs_kmap_atomic(bv->bv_page, KM_USER1);
if (rw == UIO_READ)
bcopy(p, paddr + bv->bv_offset + skip, cnt);
else
bcopy(paddr + bv->bv_offset + skip, p, cnt);
zfs_kunmap_atomic(paddr, KM_USER1);
skip += cnt;
if (skip == bv->bv_len) {
skip = 0;
uio->uio_bvec = (++bv);
uio->uio_iovcnt--;
}
uio->uio_skip = skip;
uio->uio_resid -= cnt;
uio->uio_loffset += cnt;
p = (caddr_t)p + cnt;
n -= cnt;
}
return (0);
}
#if defined(HAVE_VFS_IOV_ITER)
static int
uiomove_iter(void *p, size_t n, enum uio_rw rw, struct uio *uio,
boolean_t revert)
{
size_t cnt = MIN(n, uio->uio_resid);
if (uio->uio_skip)
iov_iter_advance(uio->uio_iter, uio->uio_skip);
if (rw == UIO_READ)
cnt = copy_to_iter(p, cnt, uio->uio_iter);
else
cnt = copy_from_iter(p, cnt, uio->uio_iter);
/*
* When operating on a full pipe no bytes are processed.
* In which case return EFAULT which is converted to EAGAIN
* by the kernel's generic_file_splice_read() function.
*/
if (cnt == 0)
return (EFAULT);
/*
* Revert advancing the uio_iter. This is set by uiocopy()
* to avoid consuming the uio and its iov_iter structure.
*/
if (revert)
iov_iter_revert(uio->uio_iter, cnt);
uio->uio_resid -= cnt;
uio->uio_loffset += cnt;
return (0);
}
#endif
int
uiomove(void *p, size_t n, enum uio_rw rw, struct uio *uio)
{
if (uio->uio_segflg == UIO_BVEC)
return (uiomove_bvec(p, n, rw, uio));
#if defined(HAVE_VFS_IOV_ITER)
else if (uio->uio_segflg == UIO_ITER)
return (uiomove_iter(p, n, rw, uio, B_FALSE));
#endif
else
return (uiomove_iov(p, n, rw, uio));
}
EXPORT_SYMBOL(uiomove);
int
uio_prefaultpages(ssize_t n, struct uio *uio)
{
struct iov_iter iter, *iterp = NULL;
#if defined(HAVE_IOV_ITER_FAULT_IN_READABLE)
if (uio->uio_segflg == UIO_USERSPACE) {
iterp = &iter;
iov_iter_init_compat(iterp, READ, uio->uio_iov,
uio->uio_iovcnt, uio->uio_resid);
#if defined(HAVE_VFS_IOV_ITER)
} else if (uio->uio_segflg == UIO_ITER) {
iterp = uio->uio_iter;
#endif
}
if (iterp && iov_iter_fault_in_readable(iterp, n))
return (EFAULT);
#endif
return (0);
}
EXPORT_SYMBOL(uio_prefaultpages);
/*
* The same as uiomove() but doesn't modify uio structure.
* return in cbytes how many bytes were copied.
*/
int
uiocopy(void *p, size_t n, enum uio_rw rw, struct uio *uio, size_t *cbytes)
{
struct uio uio_copy;
int ret;
bcopy(uio, &uio_copy, sizeof (struct uio));
if (uio->uio_segflg == UIO_BVEC)
ret = uiomove_bvec(p, n, rw, &uio_copy);
#if defined(HAVE_VFS_IOV_ITER)
else if (uio->uio_segflg == UIO_ITER)
ret = uiomove_iter(p, n, rw, &uio_copy, B_TRUE);
#endif
else
ret = uiomove_iov(p, n, rw, &uio_copy);
*cbytes = uio->uio_resid - uio_copy.uio_resid;
return (ret);
}
EXPORT_SYMBOL(uiocopy);
/*
* Drop the next n chars out of *uio.
*/
void
uioskip(uio_t *uio, size_t n)
{
if (n > uio->uio_resid)
return;
if (uio->uio_segflg == UIO_BVEC) {
uio->uio_skip += n;
while (uio->uio_iovcnt &&
uio->uio_skip >= uio->uio_bvec->bv_len) {
uio->uio_skip -= uio->uio_bvec->bv_len;
uio->uio_bvec++;
uio->uio_iovcnt--;
}
#if defined(HAVE_VFS_IOV_ITER)
} else if (uio->uio_segflg == UIO_ITER) {
iov_iter_advance(uio->uio_iter, n);
#endif
} else {
uio->uio_skip += n;
while (uio->uio_iovcnt &&
uio->uio_skip >= uio->uio_iov->iov_len) {
uio->uio_skip -= uio->uio_iov->iov_len;
uio->uio_iov++;
uio->uio_iovcnt--;
}
}
uio->uio_loffset += n;
uio->uio_resid -= n;
}
EXPORT_SYMBOL(uioskip);
#endif /* _KERNEL */
