/* $NetBSD: uvm_page_array.h,v 1.3 2020/05/25 21:15:10 ad Exp $ */
/*-
* Copyright (c)2011 YAMAMOTO Takashi,
* 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.
*
* 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 AUTHOR 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.
*/
/*
* uvm_page_array: an array of pages.
*
* these structure and functions simply manipulate struct vm_page pointers.
* it's caller's responsibity to acquire and keep the object lock so that
* the result is valid.
*
* typical usage:
*
* struct uvm_page_array a;
*
* uvm_page_array_init(&a, uobj, ...);
* while ((pg = uvm_page_array_fill_and_peek(&a, off, 0)) != NULL) {
* off = pg->offset + PAGE_SIZE;
* do_something(pg);
* uvm_page_array_advance(&a);
* }
* uvm_page_array_fini(&a);
*
* if scanning forwards the "off" argument may not go backwards.
* if scanning backwards, the "off" argument may not go forwards.
*/
struct vm_page;
struct uvm_page_array {
unsigned int ar_npages; /* valid elements in ar_pages */
unsigned int ar_idx; /* index in ar_pages */
struct uvm_object *ar_uobj;
unsigned int ar_flags;
voff_t ar_lastoff;
struct vm_page *ar_pages[16]; /* XXX tune */
};
