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This commit was manufactured by cvs2svn to create tag 'FreeBSD-release/1.1'.
[unix-history] / sys / vm / vnode_pager.c
/*
* Copyright (c) 1990 University of Utah.
* Copyright (c) 1991 The Regents of the University of California.
* All rights reserved.
* Copyright (c) 1993 John S. Dyson
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department.
*
* 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.
*
* from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91
* $Id: vnode_pager.c,v 1.11.2.2 1994/03/24 08:12:20 rgrimes Exp $
*/
/*
* Page to/from files (vnodes).
*
* TODO:
* pageouts
* fix credential use (uses current process credentials now)
*/
/*
* MODIFICATIONS:
* John S. Dyson 08 Dec 93
*
* This file in conjunction with some vm_fault mods, eliminate the performance
* advantage for using the buffer cache and minimize memory copies.
*
* 1) Supports multiple - block reads
* 2) Bypasses buffer cache for reads
*
* TODO:
*
* 1) Totally bypass buffer cache for reads
* (Currently will still sometimes use buffer cache for reads)
* 2) Bypass buffer cache for writes
* (Code does not support it, but mods are simple)
*/
#include "param.h"
#include "proc.h"
#include "malloc.h"
#include "vnode.h"
#include "uio.h"
#include "mount.h"
#include "vm_param.h"
#include "vm.h"
#include "lock.h"
#include "queue.h"
#include "vm_prot.h"
#include "vm_object.h"
#include "vm_page.h"
#include "vnode_pager.h"
#include "vm_map.h"
#include "vm_pageout.h"
#include "buf.h"
#include "specdev.h"
struct pagerops vnodepagerops = {
vnode_pager_init,
vnode_pager_alloc,
vnode_pager_dealloc,
vnode_pager_getpage,
vnode_pager_getmulti,
vnode_pager_putpage,
vnode_pager_haspage
};
static int vnode_pager_io(vn_pager_t vnp, vm_page_t *m, int count, int reqpage,
enum uio_rw rw);
struct buf * getpbuf() ;
void relpbuf(struct buf *bp) ;
extern vm_map_t pager_map;
queue_head_t vnode_pager_list; /* list of managed vnodes */
#ifdef DEBUG
int vpagerdebug = 0x00;
#define VDB_FOLLOW 0x01
#define VDB_INIT 0x02
#define VDB_IO 0x04
#define VDB_FAIL 0x08
#define VDB_ALLOC 0x10
#define VDB_SIZE 0x20
#endif
void
vnode_pager_init()
{
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_init()\n");
#endif
queue_init(&vnode_pager_list);
}
/*
* Allocate (or lookup) pager for a vnode.
* Handle is a vnode pointer.
*/
vm_pager_t
vnode_pager_alloc(handle, size, prot, offset)
caddr_t handle;
vm_size_t size;
vm_prot_t prot;
vm_offset_t offset;
{
register vm_pager_t pager;
register vn_pager_t vnp;
vm_object_t object;
struct vattr vattr;
struct vnode *vp;
struct proc *p = curproc; /* XXX */
#ifdef DEBUG
if (vpagerdebug & (VDB_FOLLOW|VDB_ALLOC))
printf("vnode_pager_alloc(%x, %x, %x)\n", handle, size, prot);
#endif
/*
* Pageout to vnode, no can do yet.
*/
if (handle == NULL)
return(NULL);
/*
* Vnodes keep a pointer to any associated pager so no need to
* lookup with vm_pager_lookup.
*/
vp = (struct vnode *)handle;
pager = (vm_pager_t)vp->v_vmdata;
if (pager == NULL) {
/*
* Allocate pager structures
*/
pager = (vm_pager_t)malloc(sizeof *pager, M_VMPAGER, M_WAITOK);
if (pager == NULL)
return(NULL);
vnp = (vn_pager_t)malloc(sizeof *vnp, M_VMPGDATA, M_WAITOK);
if (vnp == NULL) {
free((caddr_t)pager, M_VMPAGER);
return(NULL);
}
/*
* And an object of the appropriate size
*/
if (VOP_GETATTR(vp, &vattr, p->p_ucred, p) == 0) {
object = vm_object_allocate(round_page(vattr.va_size));
vm_object_enter(object, pager);
vm_object_setpager(object, pager, 0, TRUE);
} else {
free((caddr_t)vnp, M_VMPGDATA);
free((caddr_t)pager, M_VMPAGER);
return(NULL);
}
/*
* Hold a reference to the vnode and initialize pager data.
*/
VREF(vp);
vnp->vnp_flags = 0;
vnp->vnp_vp = vp;
vnp->vnp_size = vattr.va_size;
queue_enter(&vnode_pager_list, pager, vm_pager_t, pg_list);
pager->pg_handle = handle;
pager->pg_type = PG_VNODE;
pager->pg_ops = &vnodepagerops;
pager->pg_data = (caddr_t)vnp;
vp->v_vmdata = (caddr_t)pager;
} else {
/*
* vm_object_lookup() will remove the object from the
* cache if found and also gain a reference to the object.
*/
object = vm_object_lookup(pager);
#ifdef DEBUG
vnp = (vn_pager_t)pager->pg_data;
#endif
}
#ifdef DEBUG
if (vpagerdebug & VDB_ALLOC)
printf("vnode_pager_setup: vp %x sz %x pager %x object %x\n",
vp, vnp->vnp_size, pager, object);
#endif
return(pager);
}
void
vnode_pager_dealloc(pager)
vm_pager_t pager;
{
register vn_pager_t vnp = (vn_pager_t)pager->pg_data;
register struct vnode *vp;
struct proc *p = curproc; /* XXX */
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_dealloc(%x)\n", pager);
#endif
if (vp = vnp->vnp_vp) {
vp->v_vmdata = NULL;
vp->v_flag &= ~VTEXT;
#if 0
/* can hang if done at reboot on NFS FS */
(void) VOP_FSYNC(vp, p->p_ucred, p);
#endif
vrele(vp);
}
queue_remove(&vnode_pager_list, pager, vm_pager_t, pg_list);
free((caddr_t)vnp, M_VMPGDATA);
free((caddr_t)pager, M_VMPAGER);
}
int
vnode_pager_getmulti(pager, m, count, reqpage, sync)
vm_pager_t pager;
vm_page_t *m;
int count;
int reqpage;
boolean_t sync;
{
return vnode_pager_io((vn_pager_t) pager->pg_data, m, count, reqpage, UIO_READ);
}
int
vnode_pager_getpage(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
int err;
vm_page_t marray[1];
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_getpage(%x, %x)\n", pager, m);
#endif
if (pager == NULL)
return FALSE;
marray[0] = m;
return vnode_pager_io((vn_pager_t)pager->pg_data, marray, 1, 0, UIO_READ);
}
boolean_t
vnode_pager_putpage(pager, m, sync)
vm_pager_t pager;
vm_page_t m;
boolean_t sync;
{
int err;
vm_page_t marray[1];
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_putpage(%x, %x)\n", pager, m);
#endif
if (pager == NULL)
return FALSE;
marray[0] = m;
err = vnode_pager_io((vn_pager_t)pager->pg_data, marray, 1, 0, UIO_WRITE);
return err;
}
boolean_t
vnode_pager_haspage(pager, offset)
vm_pager_t pager;
vm_offset_t offset;
{
register vn_pager_t vnp = (vn_pager_t)pager->pg_data;
daddr_t bn;
int err;
#ifdef DEBUG
if (vpagerdebug & VDB_FOLLOW)
printf("vnode_pager_haspage(%x, %x)\n", pager, offset);
#endif
/*
* Offset beyond end of file, do not have the page
*/
if (offset >= vnp->vnp_size) {
#ifdef DEBUG
if (vpagerdebug & (VDB_FAIL|VDB_SIZE))
printf("vnode_pager_haspage: pg %x, off %x, size %x\n",
pager, offset, vnp->vnp_size);
#endif
return(FALSE);
}
/*
* Read the index to find the disk block to read
* from. If there is no block, report that we don't
* have this data.
*
* Assumes that the vnode has whole page or nothing.
*/
err = VOP_BMAP(vnp->vnp_vp,
offset / vnp->vnp_vp->v_mount->mnt_stat.f_bsize,
(struct vnode **)0, &bn);
if (err) {
#ifdef DEBUG
if (vpagerdebug & VDB_FAIL)
printf("vnode_pager_haspage: BMAP err %d, pg %x, off %x\n",
err, pager, offset);
#endif
return(TRUE);
}
return((long)bn < 0 ? FALSE : TRUE);
}
/*
* (XXX)
* Lets the VM system know about a change in size for a file.
* If this vnode is mapped into some address space (i.e. we have a pager
* for it) we adjust our own internal size and flush any cached pages in
* the associated object that are affected by the size change.
*
* Note: this routine may be invoked as a result of a pager put
* operation (possibly at object termination time), so we must be careful.
*/
void
vnode_pager_setsize(vp, nsize)
struct vnode *vp;
u_long nsize;
{
register vn_pager_t vnp;
register vm_object_t object;
vm_pager_t pager;
/*
* Not a mapped vnode
*/
if (vp == NULL || vp->v_type != VREG || vp->v_vmdata == NULL)
return;
/*
* Hasn't changed size
*/
pager = (vm_pager_t)vp->v_vmdata;
vnp = (vn_pager_t)pager->pg_data;
if (nsize == vnp->vnp_size)
return;
/*
* No object.
* This can happen during object termination since
* vm_object_page_clean is called after the object
* has been removed from the hash table, and clean
* may cause vnode write operations which can wind
* up back here.
*/
object = vm_object_lookup(pager);
if (object == NULL)
return;
#ifdef DEBUG
if (vpagerdebug & (VDB_FOLLOW|VDB_SIZE))
printf("vnode_pager_setsize: vp %x obj %x osz %d nsz %d\n",
vp, object, vnp->vnp_size, nsize);
#endif
/*
* File has shrunk.
* Toss any cached pages beyond the new EOF.
*/
if (round_page(nsize) < round_page(vnp->vnp_size)) {
vm_object_lock(object);
vm_object_page_remove(object,
(vm_offset_t)round_page(nsize), round_page(vnp->vnp_size));
vm_object_unlock(object);
}
vnp->vnp_size = (vm_offset_t)nsize;
vm_object_deallocate(object);
}
void
vnode_pager_umount(mp)
register struct mount *mp;
{
register vm_pager_t pager, npager;
struct vnode *vp;
pager = (vm_pager_t) queue_first(&vnode_pager_list);
while (!queue_end(&vnode_pager_list, (queue_entry_t)pager)) {
/*
* Save the next pointer now since uncaching may
* terminate the object and render pager invalid
*/
vp = ((vn_pager_t)pager->pg_data)->vnp_vp;
npager = (vm_pager_t) queue_next(&pager->pg_list);
if (mp == (struct mount *)0 || vp->v_mount == mp)
(void) vnode_pager_uncache(vp);
pager = npager;
}
}
/*
* Remove vnode associated object from the object cache.
*
* Note: this routine may be invoked as a result of a pager put
* operation (possibly at object termination time), so we must be careful.
*/
boolean_t
vnode_pager_uncache(vp)
register struct vnode *vp;
{
register vm_object_t object;
boolean_t uncached, locked;
vm_pager_t pager;
/*
* Not a mapped vnode
*/
pager = (vm_pager_t)vp->v_vmdata;
if (pager == NULL)
return (TRUE);
/*
* Unlock the vnode if it is currently locked.
* We do this since uncaching the object may result
* in its destruction which may initiate paging
* activity which may necessitate locking the vnode.
*/
locked = VOP_ISLOCKED(vp);
if (locked)
VOP_UNLOCK(vp);
/*
* Must use vm_object_lookup() as it actually removes
* the object from the cache list.
*/
object = vm_object_lookup(pager);
if (object) {
uncached = (object->ref_count <= 1);
pager_cache(object, FALSE);
} else
uncached = TRUE;
if (locked)
VOP_LOCK(vp);
return(uncached);
}
void
vnode_pager_freepage(m)
vm_page_t m;
{
PAGE_WAKEUP(m);
vm_page_free(m);
}
/*
* calculate the linear (byte) disk address of specified virtual
* file address
*/
vm_offset_t
vnode_pager_addr(vp, address)
struct vnode *vp;
vm_offset_t address;
{
int rtaddress;
int bsize;
vm_offset_t block;
struct vnode *rtvp;
int err;
int vblock, voffset;
bsize = vp->v_mount->mnt_stat.f_bsize;
vblock = address / bsize;
voffset = address % bsize;
err = VOP_BMAP(vp,vblock,&rtvp,&block);
rtaddress = block * DEV_BSIZE + voffset;
return rtaddress;
}
/*
* interrupt routine for I/O completion
*/
void
vnode_pager_iodone(bp)
struct buf *bp;
{
bp->b_flags |= B_DONE;
wakeup((caddr_t)bp);
}
/*
* vnode_pager_io:
* Perform read or write operation for vnode_paging
*
* args:
* vnp -- pointer to vnode pager data structure
* containing size and vnode pointer, etc
*
* m -- pointer to array of vm_page_t entries to
* do I/O to. It is not necessary to fill any
* pages except for the reqpage entry. If a
* page is not filled, it needs to be removed
* from its object...
*
* count -- number of pages for I/O
*
* reqpage -- fault requested page for I/O
* (index into vm_page_t entries above)
*
* rw -- UIO_READ or UIO_WRITE
*
* NOTICE!!!! direct writes look like that they are close to being
* implemented. They are not really, several things need
* to be done to make it work (subtile things.) Hack at
* your own risk (direct writes are scarey).
*
* ANOTHER NOTICE!!!!
* we currently only support direct I/O to filesystems whose
* contiguously allocated blocksize is at least a vm page.
* changes will be made in the future to support more flexibility.
*/
int
vnode_pager_io(vnp, m, count, reqpage, rw)
register vn_pager_t vnp;
vm_page_t *m;
int count, reqpage;
enum uio_rw rw;
{
int i,j;
struct uio auio;
struct iovec aiov;
vm_offset_t kva, foff;
int size;
struct proc *p = curproc; /* XXX */
vm_object_t object;
vm_offset_t paging_offset;
struct vnode *dp, *vp;
vm_offset_t mapsize;
int bsize;
int errtype=0; /* 0 is file type otherwise vm type */
int error = 0;
int trimmed;
object = m[reqpage]->object; /* all vm_page_t items are in same object */
paging_offset = object->paging_offset;
vp = vnp->vnp_vp;
bsize = vp->v_mount->mnt_stat.f_bsize;
/* get the UNDERLYING device for the file with VOP_BMAP() */
/*
* originally, we did not check for an error return
* value -- assuming an fs always has a bmap entry point
* -- that assumption is wrong!!!
*/
/*
* we only do direct I/O if the file is on a local
* BLOCK device and currently if it is a read operation only.
*/
kva = 0;
mapsize = 0;
if (!VOP_BMAP(vp, m[reqpage]->offset+paging_offset, &dp, 0) &&
rw == UIO_READ && ((dp->v_type == VBLK &&
(vp->v_mount->mnt_stat.f_type == MOUNT_UFS)) ||
(vp->v_mount->mnt_stat.f_type == MOUNT_NFS))) {
/*
* we do not block for a kva, notice we default to a kva
* conservative behavior
*/
kva = kmem_alloc_pageable(pager_map,
(mapsize = count*NBPG));
if( !kva) {
for (i = 0; i < count; i++) {
if (i != reqpage) {
vnode_pager_freepage(m[i]);
m[i] = 0;
}
}
m[0] = m[reqpage];
kva = vm_pager_map_page(m[0]);
reqpage = 0;
count = 1;
mapsize = count*NBPG;
}
}
if (!kva) {
/*
* here on I/O through VFS
*/
for (i = 0; i < count; i++) {
if (i != reqpage) {
vnode_pager_freepage(m[i]);
m[i] = 0;
}
}
m[0] = m[reqpage];
foff = m[0]->offset + paging_offset;
reqpage = 0;
count = 1;
/*
* Return failure if beyond current EOF
*/
if (foff >= vnp->vnp_size) {
errtype = 1;
error = VM_PAGER_BAD;
} else {
if (foff + NBPG > vnp->vnp_size)
size = vnp->vnp_size - foff;
else
size = NBPG;
/*
* Allocate a kernel virtual address and initialize so that
* we can use VOP_READ/WRITE routines.
*/
kva = vm_pager_map_page(m[0]);
aiov.iov_base = (caddr_t)kva;
aiov.iov_len = size;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_offset = foff;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_rw = rw;
auio.uio_resid = size;
auio.uio_procp = (struct proc *)0;
if (rw == UIO_READ) {
error = VOP_READ(vp, &auio, IO_PAGER, p->p_ucred);
} else {
error = VOP_WRITE(vp, &auio, IO_PAGER, p->p_ucred);
}
if (!error) {
register int count = size - auio.uio_resid;
if (count == 0)
error = EINVAL;
else if (count != NBPG && rw == UIO_READ)
bzero((caddr_t)kva + count, NBPG - count);
}
vm_pager_unmap_page(kva);
}
} else {
/*
* here on direct device I/O
*/
int first=0, last=count;
int reqaddr, firstaddr;
int block, offset;
struct buf *bp;
int s;
int failflag;
foff = m[reqpage]->offset + paging_offset;
/*
* This pathetic hack gets data from the buffer cache, if it's there.
* I believe that this is not really necessary, and the ends can
* be gotten by defaulting to the normal vfs read behavior, but this
* might be more efficient, because the will NOT invoke read-aheads
* and one of the purposes of this code is to bypass the buffer
* cache and keep from flushing it by reading in a program.
*/
/*
* calculate logical block and offset
*/
block = foff / bsize;
offset = foff % bsize;
s = splbio();
/*
* if we have a buffer in core, then try to use it
*/
while (bp = incore(vp, block)) {
int amount;
/*
* wait until the buffer is avail or gone
*/
if (bp->b_flags & B_BUSY) {
bp->b_flags |= B_WANTED;
tsleep ((caddr_t)bp, PVM, "vnwblk", 0);
continue;
}
amount = NBPG;
if ((foff + amount) > vnp->vnp_size)
amount = vnp->vnp_size - foff;
/*
* make sure that this page is in the buffer
*/
if ((amount > 0) && (offset + amount) <= bp->b_bcount) {
bp->b_flags |= B_BUSY;
splx(s);
/*
* map the requested page
*/
pmap_enter(vm_map_pmap(pager_map),
kva, VM_PAGE_TO_PHYS(m[reqpage]),
VM_PROT_DEFAULT, TRUE);
/*
* copy the data from the buffer
*/
bcopy(bp->b_un.b_addr + offset, (caddr_t)kva, amount);
if (amount < NBPG) {
bzero((caddr_t)kva + amount, NBPG - amount);
}
/*
* unmap the page and free the kva
*/
pmap_remove(vm_map_pmap(pager_map), kva, kva + NBPG);
kmem_free_wakeup(pager_map, kva, mapsize);
/*
* release the buffer back to the block subsystem
*/
bp->b_flags &= ~B_BUSY;
wakeup((caddr_t)bp);
/*
* we did not have to do any work to get the requested
* page, the read behind/ahead does not justify a read
*/
for (i = 0; i < count; i++) {
if (i != reqpage) {
vnode_pager_freepage(m[i]);
m[i] = 0;
}
}
/*
* sorry for the goto
*/
goto finishup;
}
/*
* buffer is nowhere to be found, read from the disk
*/
break;
}
foff = m[reqpage]->offset + paging_offset;
reqaddr = vnode_pager_addr(vp, foff);
/*
* Make sure that our I/O request is contiguous.
* Scan backward and stop for the first discontiguous
* entry or stop for a page being in buffer cache.
*/
failflag = 0;
for (i = reqpage - 1; i >= 0; --i) {
int myaddr;
if (failflag ||
incore(vp, (foff + (i - reqpage) * NBPG) / bsize) ||
(myaddr = vnode_pager_addr(vp, m[i]->offset + paging_offset))
!= reqaddr + (i - reqpage) * NBPG) {
vnode_pager_freepage(m[i]);
m[i] = 0;
if (first == 0)
first = i + 1;
failflag = 1;
}
}
/*
* Scan forward and stop for the first non-contiguous
* entry or stop for a page being in buffer cache.
*/
failflag = 0;
for (i = reqpage + 1; i < count; i++) {
int myaddr;
if (failflag ||
incore(vp, (foff + (i - reqpage) * NBPG) / bsize) ||
(myaddr = vnode_pager_addr(vp, m[i]->offset + paging_offset))
!= reqaddr + (i - reqpage) * NBPG) {
vnode_pager_freepage(m[i]);
m[i] = 0;
if (last == count)
last = i;
failflag = 1;
}
}
/*
* the first and last page have been calculated now, move input
* pages to be zero based...
*/
count = last;
if (first != 0) {
for (i = first; i < count; i++) {
m[i - first] = m[i];
}
count -= first;
reqpage -= first;
}
/*
* calculate the file virtual address for the transfer
*/
foff = m[0]->offset + paging_offset;
/*
* and get the disk physical address (in bytes)
*/
firstaddr = vnode_pager_addr(vp, foff);
/*
* calculate the size of the transfer
*/
if ((m[count - 1]->offset + paging_offset) + NBPG > vnp->vnp_size)
size = vnp->vnp_size - foff;
else
size = count * NBPG;
/*
* and map the pages to be read into the kva
*/
for (i = 0; i < count; i++)
pmap_enter(vm_map_pmap(pager_map),
kva + NBPG * i, VM_PAGE_TO_PHYS(m[i]),
VM_PROT_DEFAULT, TRUE);
VHOLD(vp);
bp = getpbuf();
/* build a minimal buffer header */
bzero((caddr_t)bp, sizeof(struct buf));
bp->b_flags = B_BUSY | B_READ | B_CALL;
bp->b_iodone = vnode_pager_iodone;
/* B_PHYS is not set, but it is nice to fill this in */
/* bp->b_proc = &proc0; */
bp->b_proc = curproc;
bp->b_rcred = bp->b_wcred = bp->b_proc->p_ucred;
bp->b_un.b_addr = (caddr_t) kva;
bp->b_blkno = firstaddr / DEV_BSIZE;
bp->b_vp = dp;
/* Should be a BLOCK or character DEVICE if we get here */
bp->b_dev = dp->v_rdev;
bp->b_bcount = NBPG * count;
/* do the input */
VOP_STRATEGY(bp);
/* we definitely need to be at splbio here */
while ((bp->b_flags & B_DONE) == 0) {
tsleep((caddr_t)bp, PVM, "vnread", 0);
}
splx(s);
if ((bp->b_flags & B_ERROR) != 0)
error = EIO;
if (!error) {
if (size != count * NBPG)
bzero((caddr_t)kva + size, NBPG * count - size);
}
HOLDRELE(vp);
pmap_remove(vm_map_pmap(pager_map), kva, kva + NBPG * count);
kmem_free_wakeup(pager_map, kva, mapsize);
/*
* free the buffer header back to the swap buffer pool
*/
relpbuf(bp);
}
finishup:
if (rw == UIO_READ)
for (i = 0; i < count; i++) {
/*
* we dont mess with pages that have been already
* deallocated....
*/
if (!m[i])
continue;
pmap_clear_modify(VM_PAGE_TO_PHYS(m[i]));
m[i]->flags |= PG_CLEAN;
m[i]->flags &= ~PG_LAUNDRY;
if (i != reqpage) {
/*
* whether or not to leave the page activated
* is up in the air, but we should put the page
* on a page queue somewhere. (it already is in
* the object).
* Result: It appears that emperical results show
* that deactivating pages is best.
*/
/*
* just in case someone was asking for this
* page we now tell them that it is ok to use
*/
if (!error) {
vm_page_deactivate(m[i]);
PAGE_WAKEUP(m[i]);
m[i]->flags &= ~PG_FAKE;
} else {
vnode_pager_freepage(m[i]);
}
}
}
if (!error && rw == UIO_WRITE) {
pmap_clear_modify(VM_PAGE_TO_PHYS(m[reqpage]));
m[reqpage]->flags |= PG_CLEAN;
m[reqpage]->flags &= ~PG_LAUNDRY;
}
if (error) {
printf("vnode pager error: %d\n", error);
}
if (errtype)
return error;
return (error ? VM_PAGER_FAIL : VM_PAGER_OK);
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.