36ac37dec4
space. When doing this, it is possible to for another process to attempt to get an exclusive lock on the vnode and deadlock the mmap/read combination when the uiomove() call tries to obtain a second shared lock on the vnode. There is still a potential deadlock situation with write()/mmap(). Submitted by: Matt Dillon <dillon@freebsd.org> Reviewed by: Luoqi Chen <luoqi@freebsd.org> Delimmitted by tag PRE_MATT_MMAP_LOCK and POST_MATT_MMAP_LOCK in kern/kern_lock.c kern/kern_subr.c
425 lines
9.4 KiB
C
425 lines
9.4 KiB
C
/*
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* Copyright (c) 1982, 1986, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
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* $Id: kern_subr.c,v 1.27 1999/02/22 18:39:49 bde Exp $
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/malloc.h>
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#include <sys/lock.h>
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#include <sys/resourcevar.h>
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#include <sys/vnode.h>
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#include <vm/vm.h>
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#include <vm/vm_prot.h>
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#include <vm/vm_page.h>
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#include <vm/vm_map.h>
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static void uio_yield __P((void));
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int
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uiomove(cp, n, uio)
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register caddr_t cp;
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register int n;
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register struct uio *uio;
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{
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register struct iovec *iov;
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u_int cnt;
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int error = 0;
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int save = 0;
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KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
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("uiomove: mode"));
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KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_procp == curproc,
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("uiomove proc"));
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if (curproc) {
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save = curproc->p_flag & P_DEADLKTREAT;
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curproc->p_flag |= P_DEADLKTREAT;
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}
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while (n > 0 && uio->uio_resid) {
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iov = uio->uio_iov;
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cnt = iov->iov_len;
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if (cnt == 0) {
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uio->uio_iov++;
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uio->uio_iovcnt--;
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continue;
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}
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if (cnt > n)
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cnt = 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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if (ticks - switchticks >= hogticks)
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uio_yield();
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if (uio->uio_rw == UIO_READ)
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error = copyout(cp, iov->iov_base, cnt);
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else
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error = copyin(iov->iov_base, cp, cnt);
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if (error)
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break;
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break;
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case UIO_SYSSPACE:
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if (uio->uio_rw == UIO_READ)
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bcopy((caddr_t)cp, iov->iov_base, cnt);
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else
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bcopy(iov->iov_base, (caddr_t)cp, cnt);
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break;
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case UIO_NOCOPY:
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break;
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}
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iov->iov_base += cnt;
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iov->iov_len -= cnt;
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uio->uio_resid -= cnt;
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uio->uio_offset += cnt;
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cp += cnt;
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n -= cnt;
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}
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if (curproc)
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curproc->p_flag = (curproc->p_flag & ~P_DEADLKTREAT) | save;
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return (error);
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}
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int
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uiomoveco(cp, n, uio, obj)
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caddr_t cp;
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int n;
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struct uio *uio;
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struct vm_object *obj;
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{
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struct iovec *iov;
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u_int cnt;
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int error;
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KASSERT(uio->uio_rw == UIO_READ || uio->uio_rw == UIO_WRITE,
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("uiomoveco: mode"));
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KASSERT(uio->uio_segflg != UIO_USERSPACE || uio->uio_procp == curproc,
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("uiomoveco proc"));
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while (n > 0 && uio->uio_resid) {
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iov = uio->uio_iov;
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cnt = iov->iov_len;
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if (cnt == 0) {
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uio->uio_iov++;
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uio->uio_iovcnt--;
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continue;
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}
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if (cnt > n)
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cnt = 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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if (ticks - switchticks >= hogticks)
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uio_yield();
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if (uio->uio_rw == UIO_READ) {
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if (vfs_ioopt && ((cnt & PAGE_MASK) == 0) &&
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((((intptr_t) iov->iov_base) & PAGE_MASK) == 0) &&
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((uio->uio_offset & PAGE_MASK) == 0) &&
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((((intptr_t) cp) & PAGE_MASK) == 0)) {
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error = vm_uiomove(&curproc->p_vmspace->vm_map, obj,
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uio->uio_offset, cnt,
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(vm_offset_t) iov->iov_base, NULL);
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} else {
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error = copyout(cp, iov->iov_base, cnt);
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}
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} else {
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error = copyin(iov->iov_base, cp, cnt);
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}
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if (error)
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return (error);
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break;
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case UIO_SYSSPACE:
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if (uio->uio_rw == UIO_READ)
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bcopy((caddr_t)cp, iov->iov_base, cnt);
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else
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bcopy(iov->iov_base, (caddr_t)cp, cnt);
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break;
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case UIO_NOCOPY:
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break;
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}
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iov->iov_base += cnt;
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iov->iov_len -= cnt;
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uio->uio_resid -= cnt;
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uio->uio_offset += cnt;
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cp += 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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uioread(n, uio, obj, nread)
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int n;
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struct uio *uio;
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struct vm_object *obj;
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int *nread;
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{
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int npagesmoved;
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struct iovec *iov;
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u_int cnt, tcnt;
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int error;
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*nread = 0;
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if (vfs_ioopt < 2)
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return 0;
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error = 0;
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while (n > 0 && uio->uio_resid) {
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iov = uio->uio_iov;
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cnt = iov->iov_len;
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if (cnt == 0) {
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uio->uio_iov++;
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uio->uio_iovcnt--;
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continue;
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}
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if (cnt > n)
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cnt = n;
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if ((uio->uio_segflg == UIO_USERSPACE) &&
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((((intptr_t) iov->iov_base) & PAGE_MASK) == 0) &&
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((uio->uio_offset & PAGE_MASK) == 0) ) {
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if (cnt < PAGE_SIZE)
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break;
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cnt &= ~PAGE_MASK;
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if (ticks - switchticks >= hogticks)
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uio_yield();
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error = vm_uiomove(&curproc->p_vmspace->vm_map, obj,
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uio->uio_offset, cnt,
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(vm_offset_t) iov->iov_base, &npagesmoved);
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if (npagesmoved == 0)
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break;
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tcnt = npagesmoved * PAGE_SIZE;
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cnt = tcnt;
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if (error)
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break;
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iov->iov_base += cnt;
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iov->iov_len -= cnt;
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uio->uio_resid -= cnt;
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uio->uio_offset += cnt;
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*nread += cnt;
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n -= cnt;
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} else {
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break;
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}
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}
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return error;
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}
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/*
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* Give next character to user as result of read.
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*/
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int
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ureadc(c, uio)
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register int c;
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register struct uio *uio;
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{
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register struct iovec *iov;
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again:
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if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
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panic("ureadc");
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iov = uio->uio_iov;
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if (iov->iov_len == 0) {
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uio->uio_iovcnt--;
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uio->uio_iov++;
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goto again;
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}
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switch (uio->uio_segflg) {
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case UIO_USERSPACE:
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if (subyte(iov->iov_base, c) < 0)
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return (EFAULT);
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break;
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case UIO_SYSSPACE:
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*iov->iov_base = c;
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break;
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case UIO_USERISPACE:
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if (suibyte(iov->iov_base, c) < 0)
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return (EFAULT);
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break;
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case UIO_NOCOPY:
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break;
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}
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iov->iov_base++;
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iov->iov_len--;
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uio->uio_resid--;
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uio->uio_offset++;
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return (0);
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}
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#ifdef vax /* unused except by ct.c, other oddities XXX */
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/*
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* Get next character written in by user from uio.
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*/
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int
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uwritec(uio)
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struct uio *uio;
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{
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register struct iovec *iov;
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register int c;
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if (uio->uio_resid <= 0)
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return (-1);
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again:
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if (uio->uio_iovcnt <= 0)
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panic("uwritec");
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iov = uio->uio_iov;
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if (iov->iov_len == 0) {
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uio->uio_iov++;
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if (--uio->uio_iovcnt == 0)
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return (-1);
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goto again;
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}
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switch (uio->uio_segflg) {
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case UIO_USERSPACE:
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c = fubyte(iov->iov_base);
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break;
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case UIO_SYSSPACE:
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c = *(u_char *) iov->iov_base;
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break;
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case UIO_USERISPACE:
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c = fuibyte(iov->iov_base);
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break;
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}
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if (c < 0)
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return (-1);
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iov->iov_base++;
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iov->iov_len--;
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uio->uio_resid--;
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uio->uio_offset++;
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return (c);
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}
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#endif /* vax */
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/*
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* General routine to allocate a hash table.
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*/
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void *
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hashinit(elements, type, hashmask)
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int elements;
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struct malloc_type *type;
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u_long *hashmask;
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{
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long hashsize;
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LIST_HEAD(generic, generic) *hashtbl;
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int i;
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if (elements <= 0)
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panic("hashinit: bad elements");
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for (hashsize = 1; hashsize <= elements; hashsize <<= 1)
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continue;
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hashsize >>= 1;
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hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
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for (i = 0; i < hashsize; i++)
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LIST_INIT(&hashtbl[i]);
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*hashmask = hashsize - 1;
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return (hashtbl);
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}
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static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039,
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2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
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7159, 7673, 8191, 12281, 16381, 24571, 32749 };
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#define NPRIMES (sizeof(primes) / sizeof(primes[0]))
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/*
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* General routine to allocate a prime number sized hash table.
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*/
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void *
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phashinit(elements, type, nentries)
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int elements;
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struct malloc_type *type;
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u_long *nentries;
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{
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long hashsize;
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LIST_HEAD(generic, generic) *hashtbl;
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int i;
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if (elements <= 0)
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panic("phashinit: bad elements");
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for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
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i++;
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if (i == NPRIMES)
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break;
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hashsize = primes[i];
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}
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hashsize = primes[i - 1];
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hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
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for (i = 0; i < hashsize; i++)
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LIST_INIT(&hashtbl[i]);
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*nentries = hashsize;
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return (hashtbl);
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}
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static void
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uio_yield()
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{
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struct proc *p;
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int s;
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p = curproc;
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p->p_priority = p->p_usrpri;
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s = splhigh();
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setrunqueue(p);
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p->p_stats->p_ru.ru_nivcsw++;
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mi_switch();
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splx(s);
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}
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