279 lines
6.5 KiB
C
279 lines
6.5 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
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/* All Rights Reserved */
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/*
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* University Copyright- Copyright (c) 1982, 1986, 1988
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* The Regents of the University of California
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* All Rights Reserved
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*
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* University Acknowledgment- Portions of this document are derived from
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* software developed by the University of California, Berkeley, and its
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* contributors.
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*/
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/*
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* Copyright (c) 2015 by Chunwei Chen. All rights reserved.
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*/
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/*
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* The uio support from OpenSolaris has been added as a short term
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* work around. The hope is to adopt native Linux type and drop the
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* use of uio's entirely. Under Linux they only add overhead and
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* when possible we want to use native APIs for the ZPL layer.
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*/
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#ifdef _KERNEL
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#include <sys/types.h>
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#include <sys/uio_impl.h>
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#include <sys/sysmacros.h>
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#include <sys/strings.h>
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#include <linux/kmap_compat.h>
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#include <linux/uaccess.h>
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/*
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* Move "n" bytes at byte address "p"; "rw" indicates the direction
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* of the move, and the I/O parameters are provided in "uio", which is
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* update to reflect the data which was moved. Returns 0 on success or
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* a non-zero errno on failure.
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*/
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static int
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uiomove_iov(void *p, size_t n, enum uio_rw rw, struct uio *uio)
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{
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const struct iovec *iov = uio->uio_iov;
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size_t skip = uio->uio_skip;
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ulong_t cnt;
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while (n && uio->uio_resid) {
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cnt = MIN(iov->iov_len - skip, n);
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switch (uio->uio_segflg) {
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case UIO_USERSPACE:
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case UIO_USERISPACE:
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/*
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* p = kernel data pointer
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* iov->iov_base = user data pointer
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*/
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if (rw == UIO_READ) {
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if (copy_to_user(iov->iov_base+skip, p, cnt))
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return (EFAULT);
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} else {
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if (uio->uio_fault_disable) {
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if (!zfs_access_ok(VERIFY_READ,
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(iov->iov_base + skip), cnt)) {
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return (EFAULT);
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}
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pagefault_disable();
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if (__copy_from_user_inatomic(p,
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(iov->iov_base + skip), cnt)) {
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pagefault_enable();
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return (EFAULT);
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}
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pagefault_enable();
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} else {
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if (copy_from_user(p,
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(iov->iov_base + skip), cnt))
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return (EFAULT);
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}
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}
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break;
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case UIO_SYSSPACE:
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if (rw == UIO_READ)
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bcopy(p, iov->iov_base + skip, cnt);
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else
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bcopy(iov->iov_base + skip, p, cnt);
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break;
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default:
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ASSERT(0);
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}
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skip += cnt;
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if (skip == iov->iov_len) {
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skip = 0;
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uio->uio_iov = (++iov);
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uio->uio_iovcnt--;
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}
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uio->uio_skip = skip;
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uio->uio_resid -= cnt;
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uio->uio_loffset += cnt;
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p = (caddr_t)p + cnt;
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n -= cnt;
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}
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return (0);
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}
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static int
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uiomove_bvec(void *p, size_t n, enum uio_rw rw, struct uio *uio)
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{
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const struct bio_vec *bv = uio->uio_bvec;
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size_t skip = uio->uio_skip;
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ulong_t cnt;
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while (n && uio->uio_resid) {
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void *paddr;
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cnt = MIN(bv->bv_len - skip, n);
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paddr = zfs_kmap_atomic(bv->bv_page, KM_USER1);
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if (rw == UIO_READ)
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bcopy(p, paddr + bv->bv_offset + skip, cnt);
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else
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bcopy(paddr + bv->bv_offset + skip, p, cnt);
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zfs_kunmap_atomic(paddr, KM_USER1);
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skip += cnt;
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if (skip == bv->bv_len) {
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skip = 0;
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uio->uio_bvec = (++bv);
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uio->uio_iovcnt--;
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}
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uio->uio_skip = skip;
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uio->uio_resid -= cnt;
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uio->uio_loffset += cnt;
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p = (caddr_t)p + cnt;
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n -= cnt;
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}
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return (0);
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}
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int
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uiomove(void *p, size_t n, enum uio_rw rw, struct uio *uio)
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{
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if (uio->uio_segflg != UIO_BVEC)
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return (uiomove_iov(p, n, rw, uio));
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else
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return (uiomove_bvec(p, n, rw, uio));
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}
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EXPORT_SYMBOL(uiomove);
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#define fuword8(uptr, vptr) get_user((*vptr), (uptr))
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/*
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* Fault in the pages of the first n bytes specified by the uio structure.
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* 1 byte in each page is touched and the uio struct is unmodified. Any
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* error will terminate the process as this is only a best attempt to get
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* the pages resident.
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*/
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int
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uio_prefaultpages(ssize_t n, struct uio *uio)
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{
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const struct iovec *iov;
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ulong_t cnt, incr;
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caddr_t p;
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uint8_t tmp;
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int iovcnt;
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size_t skip;
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/* no need to fault in kernel pages */
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switch (uio->uio_segflg) {
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case UIO_SYSSPACE:
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case UIO_BVEC:
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return (0);
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case UIO_USERSPACE:
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case UIO_USERISPACE:
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break;
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default:
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ASSERT(0);
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}
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iov = uio->uio_iov;
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iovcnt = uio->uio_iovcnt;
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skip = uio->uio_skip;
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for (; n > 0 && iovcnt > 0; iov++, iovcnt--, skip = 0) {
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cnt = MIN(iov->iov_len - skip, n);
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/* empty iov */
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if (cnt == 0)
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continue;
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n -= cnt;
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/*
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* touch each page in this segment.
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*/
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p = iov->iov_base + skip;
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while (cnt) {
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if (fuword8((uint8_t *)p, &tmp))
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return (EFAULT);
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incr = MIN(cnt, PAGESIZE);
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p += incr;
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cnt -= incr;
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}
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/*
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* touch the last byte in case it straddles a page.
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*/
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p--;
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if (fuword8((uint8_t *)p, &tmp))
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return (EFAULT);
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}
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return (0);
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}
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EXPORT_SYMBOL(uio_prefaultpages);
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/*
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* same as uiomove() but doesn't modify uio structure.
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* return in cbytes how many bytes were copied.
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*/
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int
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uiocopy(void *p, size_t n, enum uio_rw rw, struct uio *uio, size_t *cbytes)
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{
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struct uio uio_copy;
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int ret;
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bcopy(uio, &uio_copy, sizeof (struct uio));
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ret = uiomove(p, n, rw, &uio_copy);
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*cbytes = uio->uio_resid - uio_copy.uio_resid;
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return (ret);
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}
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EXPORT_SYMBOL(uiocopy);
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/*
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* Drop the next n chars out of *uiop.
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*/
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void
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uioskip(uio_t *uiop, size_t n)
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{
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if (n > uiop->uio_resid)
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return;
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uiop->uio_skip += n;
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if (uiop->uio_segflg != UIO_BVEC) {
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while (uiop->uio_iovcnt &&
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uiop->uio_skip >= uiop->uio_iov->iov_len) {
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uiop->uio_skip -= uiop->uio_iov->iov_len;
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uiop->uio_iov++;
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uiop->uio_iovcnt--;
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}
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} else {
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while (uiop->uio_iovcnt &&
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uiop->uio_skip >= uiop->uio_bvec->bv_len) {
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uiop->uio_skip -= uiop->uio_bvec->bv_len;
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uiop->uio_bvec++;
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uiop->uio_iovcnt--;
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}
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}
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uiop->uio_loffset += n;
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uiop->uio_resid -= n;
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}
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EXPORT_SYMBOL(uioskip);
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#endif /* _KERNEL */
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