freebsd-dev/sys/kern/uipc_cow.c
Alan Cox d3cb0d99e0 Introduce two new options, "CPU private" and "no wait", to sf_buf_alloc().
Change the spelling of the "catch" option to be consistent with the new
options.  Implement the "no wait" option.  An implementation of the "CPU
private" for i386 will be committed at a later date.
2004-11-08 00:43:46 +00:00

180 lines
4.4 KiB
C

/*-
* Copyright (c) 1997, Duke University
* All rights reserved.
*
* Author:
* Andrew Gallatin <gallatin@cs.duke.edu>
*
* 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. The name of Duke University may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY DUKE UNIVERSITY ``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 DUKE UNIVERSITY 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 PROFITSOR 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.
*/
/*
* This is a set of routines for enabling and disabling copy on write
* protection for data written into sockets.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/mbuf.h>
#include <sys/sf_buf.h>
#include <sys/socketvar.h>
#include <sys/uio.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_object.h>
struct netsend_cow_stats {
int attempted;
int fail_not_mapped;
int fail_sf_buf;
int success;
int iodone;
};
static struct netsend_cow_stats socow_stats;
static void socow_iodone(void *addr, void *args);
static void
socow_iodone(void *addr, void *args)
{
struct sf_buf *sf;
vm_page_t pp;
sf = args;
pp = sf_buf_page(sf);
sf_buf_free(sf);
/* remove COW mapping */
vm_page_lock_queues();
vm_page_cowclear(pp);
vm_page_unwire(pp, 0);
/*
* Check for the object going away on us. This can
* happen since we don't hold a reference to it.
* If so, we're responsible for freeing the page.
*/
if (pp->wire_count == 0 && pp->object == NULL)
vm_page_free(pp);
vm_page_unlock_queues();
socow_stats.iodone++;
}
int
socow_setup(struct mbuf *m0, struct uio *uio)
{
struct sf_buf *sf;
vm_page_t pp;
vm_paddr_t pa;
struct iovec *iov;
struct vmspace *vmspace;
struct vm_map *map;
vm_offset_t uva;
int s;
vmspace = curproc->p_vmspace;
map = &vmspace->vm_map;
uva = (vm_offset_t) uio->uio_iov->iov_base;
s = splvm();
/*
* verify page is mapped & not already wired for i/o
*/
socow_stats.attempted++;
pa=pmap_extract(map->pmap, uva);
if(!pa) {
socow_stats.fail_not_mapped++;
splx(s);
return(0);
}
pp = PHYS_TO_VM_PAGE(pa);
/*
* set up COW
*/
vm_page_lock_queues();
vm_page_cowsetup(pp);
/*
* wire the page for I/O
*/
vm_page_wire(pp);
vm_page_unlock_queues();
/*
* Allocate an sf buf
*/
sf = sf_buf_alloc(pp, SFB_CATCH);
if (!sf) {
vm_page_lock_queues();
vm_page_cowclear(pp);
vm_page_unwire(pp, 0);
/*
* Check for the object going away on us. This can
* happen since we don't hold a reference to it.
* If so, we're responsible for freeing the page.
*/
if (pp->wire_count == 0 && pp->object == NULL)
vm_page_free(pp);
vm_page_unlock_queues();
socow_stats.fail_sf_buf++;
splx(s);
return(0);
}
/*
* attach to mbuf
*/
m0->m_data = (caddr_t)sf_buf_kva(sf);
m0->m_len = PAGE_SIZE;
MEXTADD(m0, sf_buf_kva(sf), PAGE_SIZE, socow_iodone, sf, M_RDONLY,
EXT_SFBUF);
socow_stats.success++;
iov = uio->uio_iov;
iov->iov_base = (char *)iov->iov_base + PAGE_SIZE;
iov->iov_len -= PAGE_SIZE;
uio->uio_resid -= PAGE_SIZE;
uio->uio_offset += PAGE_SIZE;
if (iov->iov_len == 0) {
uio->uio_iov++;
uio->uio_iovcnt--;
}
splx(s);
return(1);
}