176 lines
4.2 KiB
C
176 lines
4.2 KiB
C
/*-
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* Copyright (c) 1997, Duke University
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* All rights reserved.
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*
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* Author:
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* Andrew Gallatin <gallatin@cs.duke.edu>
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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. The name of Duke University may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY DUKE UNIVERSITY ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DUKE UNIVERSITY BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITSOR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
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* IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* This is a set of routines for enabling and disabling copy on write
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* protection for data written into sockets.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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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/lock.h>
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#include <sys/mutex.h>
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#include <sys/mbuf.h>
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#include <sys/sf_buf.h>
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#include <sys/socketvar.h>
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#include <sys/uio.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include <vm/vm_page.h>
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#include <vm/vm_object.h>
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struct netsend_cow_stats {
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int attempted;
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int fail_not_mapped;
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int fail_sf_buf;
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int success;
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int iodone;
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};
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static struct netsend_cow_stats socow_stats;
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static void socow_iodone(void *addr, void *args);
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static void
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socow_iodone(void *addr, void *args)
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{
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int s;
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struct sf_buf *sf;
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vm_page_t pp;
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sf = args;
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pp = sf_buf_page(sf);
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s = splvm();
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/* remove COW mapping */
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vm_page_lock_queues();
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vm_page_cowclear(pp);
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vm_page_unlock_queues();
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splx(s);
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/* note that sf_buf_free() unwires the page for us*/
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sf_buf_free(addr, args);
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socow_stats.iodone++;
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}
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int
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socow_setup(struct mbuf *m0, struct uio *uio)
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{
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struct sf_buf *sf;
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vm_page_t pp;
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vm_paddr_t pa;
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struct iovec *iov;
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struct vmspace *vmspace;
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struct vm_map *map;
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vm_offset_t uva;
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int s;
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vmspace = curproc->p_vmspace;
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map = &vmspace->vm_map;
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uva = (vm_offset_t) uio->uio_iov->iov_base;
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s = splvm();
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/*
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* verify page is mapped & not already wired for i/o
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*/
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socow_stats.attempted++;
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pa=pmap_extract(map->pmap, uva);
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if(!pa) {
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socow_stats.fail_not_mapped++;
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splx(s);
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return(0);
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}
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pp = PHYS_TO_VM_PAGE(pa);
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/*
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* set up COW
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*/
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vm_page_lock_queues();
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vm_page_cowsetup(pp);
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/*
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* wire the page for I/O
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*/
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vm_page_wire(pp);
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vm_page_unlock_queues();
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/*
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* Allocate an sf buf
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*/
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sf = sf_buf_alloc(pp);
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if (!sf) {
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vm_page_lock_queues();
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vm_page_cowclear(pp);
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vm_page_unwire(pp, 0);
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/*
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* Check for the object going away on us. This can
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* happen since we don't hold a reference to it.
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* If so, we're responsible for freeing the page.
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*/
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if (pp->wire_count == 0 && pp->object == NULL)
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vm_page_free(pp);
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vm_page_unlock_queues();
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socow_stats.fail_sf_buf++;
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splx(s);
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return(0);
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}
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/*
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* attach to mbuf
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*/
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m0->m_data = (caddr_t)sf_buf_kva(sf);
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m0->m_len = PAGE_SIZE;
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MEXTADD(m0, sf_buf_kva(sf), PAGE_SIZE, socow_iodone, sf, M_RDONLY,
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EXT_SFBUF);
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socow_stats.success++;
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iov = uio->uio_iov;
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iov->iov_base = (char *)iov->iov_base + PAGE_SIZE;
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iov->iov_len -= PAGE_SIZE;
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uio->uio_resid -= PAGE_SIZE;
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uio->uio_offset += PAGE_SIZE;
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if (iov->iov_len == 0) {
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uio->uio_iov++;
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uio->uio_iovcnt--;
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}
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splx(s);
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return(1);
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}
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