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/*
* Copyright (c) 1999 Artur Grabowski <art@openbsd.org>
* All rights reserved.
*
* 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. Neither the name of the author nor the names of his contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHORS 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.
*/
#include <vm/vm.h> /* for PAGE_SIZE */
/*
* If the number of pages we're about to transfer is smaller than this number
* we use the pre-allocated array.
*/
#define UVM_UIO_SMALL_PAGES 8
/*
* Limit transfers to this number to avoid running out of memory.
*/
#define UVM_UIO_LIMIT (256 * PAGE_SIZE)
/*
* m_ext structure.
*/
struct uvm_mbuf {
struct vm_page **um_pages; /* The pages */
int um_npages; /* number of pages */
int um_usecount; /* ref cnt */
vaddr_t um_kva; /* where the pages are mapped */
struct vm_page *um_pages_small[UVM_UIO_SMALL_PAGES];
};
extern int uvm_uio_enable;
#define UVM_UIO_MINIO PAGE_SIZE /* XXX - tweak */
#define UVM_UIO_TRY(uio) (uvm_uio_enable && \
((uio)->uio_iov->iov_len >= UVM_UIO_MINIO) && \
((uio)->uio_procp != NULL) && \
((uio)->uio_rw == UIO_WRITE) && \
((uio)->uio_segflg == UIO_USERSPACE))
size_t uvm_uio_to_mbuf __P((struct uio *, struct mbuf *));
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