diff options
Diffstat (limited to 'sys/kern/uipc_cow.c')
| -rw-r--r-- | sys/kern/uipc_cow.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/sys/kern/uipc_cow.c b/sys/kern/uipc_cow.c new file mode 100644 index 0000000..239e7c5 --- /dev/null +++ b/sys/kern/uipc_cow.c @@ -0,0 +1,181 @@ +/*- + * 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgements: + * This product includes software developed by Duke University + * 4. 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. + * + * $FreeBSD$ + */ +/* + * This is a set of routines for enabling and disabling copy on write + * protection for data written into sockets. + */ + +#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/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> +#if 0 +#include <vm/vm_pager.h> +#include <vm/vm_kern.h> +#include <vm/vm_extern.h> +#include <vm/vm_zone.h> +#include <vm/swap_pager.h> +#endif + + +struct netsend_cow_stats { + int attempted; + int fail_not_mapped; + int fail_wired; + int fail_not_anon; + int fail_pmap_cow; + int fail_pg_error; + int fail_kva; + int free_post_exit; + int success; + int iodone; + int freed; +}; + +static struct netsend_cow_stats socow_stats = {0,0,0,0,0,0,0,0,0,0,0}; + +extern struct sf_buf *sf_bufs; +extern vm_offset_t sf_base; +#define dtosf(x) (&sf_bufs[((uintptr_t)(x) - (uintptr_t)sf_base) >> PAGE_SHIFT]) +void sf_buf_free(caddr_t addr, void *args); +struct sf_buf *sf_buf_alloc(void); +static void socow_iodone(caddr_t addr, void *args); + +static void +socow_iodone(caddr_t addr, void *args) +{ + int s; + struct sf_buf *sf; + + vm_offset_t paddr; + vm_page_t pp; + + sf = dtosf(addr); + paddr = vtophys((vm_offset_t)addr); + pp = PHYS_TO_VM_PAGE(paddr); + s = splvm(); + /* remove COW mapping */ + vm_page_cowclear(pp); + vm_object_deallocate(pp->object); + splx(s); + /* note that sf_buf_free() unwires the page for us*/ + sf_buf_free(addr, NULL); + socow_stats.iodone++; +} + +int +socow_setup(struct mbuf *m0, struct uio *uio) +{ + struct sf_buf *sf; + vm_page_t pp; + vm_offset_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); + + sf = sf_buf_alloc(); + sf->m = pp; + pmap_qenter(sf->kva, &pp, 1); + + /* + * set up COW + */ + vm_page_cowsetup(pp); + + /* + * wire the page for I/O + */ + vm_page_wire(pp); + + /* + * prevent the process from exiting on us. + */ + vm_object_reference(pp->object); + + /* + * attach to mbuf + */ + m0->m_data = (caddr_t)sf->kva; + m0->m_len = PAGE_SIZE; + MEXTADD(m0, sf->kva, PAGE_SIZE, socow_iodone, NULL, 0, EXT_SFBUF); + socow_stats.success++; + + iov = uio->uio_iov; + 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); +} |
