freebsd-dev/sys/kern/kern_subr.c
dyson 2957cf991c Make our v_usecount vnode reference count work identically to the
original BSD code.  The association between the vnode and the vm_object
no longer includes reference counts.  The major difference is that
vm_object's are no longer freed gratuitiously from the vnode, and so
once an object is created for the vnode, it will last as long as the
vnode does.

When a vnode object reference count is incremented, then the underlying
vnode reference count is incremented also.  The two "objects" are now
more intimately related, and so the interactions are now much less
complex.

When vnodes are now normally placed onto the free queue with an object still
attached.  The rundown of the object happens at vnode rundown time, and
happens with exactly the same filesystem semantics of the original VFS
code.  There is absolutely no need for vnode_pager_uncache and other
travesties like that anymore.

A side-effect of these changes is that SMP locking should be much simpler,
the I/O copyin/copyout optimizations work, NFS should be more ponderable,
and further work on layered filesystems should be less frustrating, because
of the totally coherent management of the vnode objects and vnodes.

Please be careful with your system while running this code, but I would
greatly appreciate feedback as soon a reasonably possible.
1998-01-06 05:26:17 +00:00

392 lines
8.7 KiB
C

/*
* Copyright (c) 1982, 1986, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
* $Id: kern_subr.c,v 1.14 1997/12/19 09:03:23 dyson Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/lock.h>
#include <vm/vm.h>
#include <vm/vm_prot.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
int
uiomove(cp, n, uio)
register caddr_t cp;
register int n;
register struct uio *uio;
{
register struct iovec *iov;
u_int cnt;
int error;
#ifdef DIAGNOSTIC
if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE)
panic("uiomove: mode");
if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc)
panic("uiomove proc");
#endif
while (n > 0 && uio->uio_resid) {
iov = uio->uio_iov;
cnt = iov->iov_len;
if (cnt == 0) {
uio->uio_iov++;
uio->uio_iovcnt--;
continue;
}
if (cnt > n)
cnt = n;
switch (uio->uio_segflg) {
case UIO_USERSPACE:
case UIO_USERISPACE:
if (uio->uio_rw == UIO_READ)
error = copyout(cp, iov->iov_base, cnt);
else
error = copyin(iov->iov_base, cp, cnt);
if (error)
return (error);
break;
case UIO_SYSSPACE:
if (uio->uio_rw == UIO_READ)
bcopy((caddr_t)cp, iov->iov_base, cnt);
else
bcopy(iov->iov_base, (caddr_t)cp, cnt);
break;
case UIO_NOCOPY:
break;
}
iov->iov_base += cnt;
iov->iov_len -= cnt;
uio->uio_resid -= cnt;
uio->uio_offset += cnt;
cp += cnt;
n -= cnt;
}
return (0);
}
int
uiomoveco(cp, n, uio, obj)
caddr_t cp;
int n;
struct uio *uio;
struct vm_object *obj;
{
struct iovec *iov;
u_int cnt;
int error;
#ifdef DIAGNOSTIC
if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE)
panic("uiomove: mode");
if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc)
panic("uiomove proc");
#endif
while (n > 0 && uio->uio_resid) {
iov = uio->uio_iov;
cnt = iov->iov_len;
if (cnt == 0) {
uio->uio_iov++;
uio->uio_iovcnt--;
continue;
}
if (cnt > n)
cnt = n;
switch (uio->uio_segflg) {
case UIO_USERSPACE:
case UIO_USERISPACE:
if (uio->uio_rw == UIO_READ) {
if (((cnt & PAGE_MASK) == 0) &&
((((int) iov->iov_base) & PAGE_MASK) == 0) &&
((uio->uio_offset & PAGE_MASK) == 0) &&
((((int) cp) & PAGE_MASK) == 0)) {
error = vm_uiomove(&curproc->p_vmspace->vm_map, obj,
uio->uio_offset, cnt,
(vm_offset_t) iov->iov_base, NULL);
} else {
error = copyout(cp, iov->iov_base, cnt);
}
} else {
error = copyin(iov->iov_base, cp, cnt);
}
if (error)
return (error);
break;
case UIO_SYSSPACE:
if (uio->uio_rw == UIO_READ)
bcopy((caddr_t)cp, iov->iov_base, cnt);
else
bcopy(iov->iov_base, (caddr_t)cp, cnt);
break;
case UIO_NOCOPY:
break;
}
iov->iov_base += cnt;
iov->iov_len -= cnt;
uio->uio_resid -= cnt;
uio->uio_offset += cnt;
cp += cnt;
n -= cnt;
}
return (0);
}
int
uioread(n, uio, obj, nread)
int n;
struct uio *uio;
struct vm_object *obj;
int *nread;
{
int npagesmoved;
struct iovec *iov;
u_int cnt, tcnt;
int error;
*nread = 0;
error = 0;
while (n > 0 && uio->uio_resid) {
iov = uio->uio_iov;
cnt = iov->iov_len;
if (cnt == 0) {
uio->uio_iov++;
uio->uio_iovcnt--;
continue;
}
if (cnt > n)
cnt = n;
if ((uio->uio_segflg == UIO_USERSPACE) &&
((((int) iov->iov_base) & PAGE_MASK) == 0) &&
((uio->uio_offset & PAGE_MASK) == 0) ) {
if (cnt < PAGE_SIZE)
break;
cnt &= ~PAGE_MASK;
error = vm_uiomove(&curproc->p_vmspace->vm_map, obj,
uio->uio_offset, cnt,
(vm_offset_t) iov->iov_base, &npagesmoved);
if (npagesmoved == 0)
break;
tcnt = npagesmoved * PAGE_SIZE;
if (tcnt != cnt) {
cnt = tcnt;
}
if (error)
break;
iov->iov_base += cnt;
iov->iov_len -= cnt;
uio->uio_resid -= cnt;
uio->uio_offset += cnt;
*nread += cnt;
n -= cnt;
} else {
break;
}
}
return error;
}
/*
* Give next character to user as result of read.
*/
int
ureadc(c, uio)
register int c;
register struct uio *uio;
{
register struct iovec *iov;
again:
if (uio->uio_iovcnt == 0 || uio->uio_resid == 0)
panic("ureadc");
iov = uio->uio_iov;
if (iov->iov_len == 0) {
uio->uio_iovcnt--;
uio->uio_iov++;
goto again;
}
switch (uio->uio_segflg) {
case UIO_USERSPACE:
if (subyte(iov->iov_base, c) < 0)
return (EFAULT);
break;
case UIO_SYSSPACE:
*iov->iov_base = c;
break;
case UIO_USERISPACE:
if (suibyte(iov->iov_base, c) < 0)
return (EFAULT);
break;
case UIO_NOCOPY:
break;
}
iov->iov_base++;
iov->iov_len--;
uio->uio_resid--;
uio->uio_offset++;
return (0);
}
#ifdef vax /* unused except by ct.c, other oddities XXX */
/*
* Get next character written in by user from uio.
*/
int
uwritec(uio)
struct uio *uio;
{
register struct iovec *iov;
register int c;
if (uio->uio_resid <= 0)
return (-1);
again:
if (uio->uio_iovcnt <= 0)
panic("uwritec");
iov = uio->uio_iov;
if (iov->iov_len == 0) {
uio->uio_iov++;
if (--uio->uio_iovcnt == 0)
return (-1);
goto again;
}
switch (uio->uio_segflg) {
case UIO_USERSPACE:
c = fubyte(iov->iov_base);
break;
case UIO_SYSSPACE:
c = *(u_char *) iov->iov_base;
break;
case UIO_USERISPACE:
c = fuibyte(iov->iov_base);
break;
}
if (c < 0)
return (-1);
iov->iov_base++;
iov->iov_len--;
uio->uio_resid--;
uio->uio_offset++;
return (c);
}
#endif /* vax */
/*
* General routine to allocate a hash table.
*/
void *
hashinit(elements, type, hashmask)
int elements;
struct malloc_type *type;
u_long *hashmask;
{
long hashsize;
LIST_HEAD(generic, generic) *hashtbl;
int i;
if (elements <= 0)
panic("hashinit: bad elements");
for (hashsize = 1; hashsize <= elements; hashsize <<= 1)
continue;
hashsize >>= 1;
hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
for (i = 0; i < hashsize; i++)
LIST_INIT(&hashtbl[i]);
*hashmask = hashsize - 1;
return (hashtbl);
}
static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039,
2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653,
7159, 7673, 8191, 12281, 16381, 24571, 32749 };
#define NPRIMES (sizeof(primes) / sizeof(primes[0]))
/*
* General routine to allocate a prime number sized hash table.
*/
void *
phashinit(elements, type, nentries)
int elements;
struct malloc_type *type;
u_long *nentries;
{
long hashsize;
LIST_HEAD(generic, generic) *hashtbl;
int i;
if (elements <= 0)
panic("phashinit: bad elements");
for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
i++;
if (i == NPRIMES)
break;
hashsize = primes[i];
}
hashsize = primes[i - 1];
hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
for (i = 0; i < hashsize; i++)
LIST_INIT(&hashtbl[i]);
*nentries = hashsize;
return (hashtbl);
}