22e53424b2
Added a new type to uiomove - "UIO_NOCOPY" which causes it to update pointers and counts, but doesn't do any data copying. This is needed for upcoming changes to the way that the vnode pager does its page outs. Added a new hash init function call "phashinit" that allocates and initializes a prime number sized hash table. vfs_cache.c: Changed hashing algorithm to use the remainder of dividing by a prime number to improve the distribution characteristcs. Uses new phashinit function in kern_subr.c.
251 lines
6.1 KiB
C
251 lines
6.1 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 1.4 1995/02/12 09:11:47 davidg 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/proc.h>
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#include <sys/malloc.h>
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#include <sys/queue.h>
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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;
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#ifdef DIAGNOSTIC
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if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE)
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panic("uiomove: mode");
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if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc)
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panic("uiomove proc");
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#endif
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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 (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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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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/*
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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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}
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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, 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 cnt");
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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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#define NPRIMES 24
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static int primes[] = { 61, 127, 251, 509, 761, 1021, 1531, 2039, 2557,
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3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
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7159, 7673, 8191, 12281, 16381, 24571, 32749 };
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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, 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("hashinit: bad cnt");
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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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