1 /* $NetBSD: uvm_page_array.h,v 1.3 2020/05/25 21:15:10 ad Exp $ */ 2 3 /*- 4 * Copyright (c)2011 YAMAMOTO Takashi, 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #if !defined(_UVM_UVM_PAGE_ARRAY_H_) 30 #define _UVM_UVM_PAGE_ARRAY_H_ 31 32 /* 33 * uvm_page_array: an array of pages. 34 * 35 * these structure and functions simply manipulate struct vm_page pointers. 36 * it's caller's responsibity to acquire and keep the object lock so that 37 * the result is valid. 38 * 39 * typical usage: 40 * 41 * struct uvm_page_array a; 42 * 43 * uvm_page_array_init(&a, uobj, ...); 44 * while ((pg = uvm_page_array_fill_and_peek(&a, off, 0)) != NULL) { 45 * off = pg->offset + PAGE_SIZE; 46 * do_something(pg); 47 * uvm_page_array_advance(&a); 48 * } 49 * uvm_page_array_fini(&a); 50 * 51 * if scanning forwards the "off" argument may not go backwards. 52 * if scanning backwards, the "off" argument may not go forwards. 53 */ 54 55 struct vm_page; 56 57 struct uvm_page_array { 58 unsigned int ar_npages; /* valid elements in ar_pages */ 59 unsigned int ar_idx; /* index in ar_pages */ 60 struct uvm_object *ar_uobj; 61 unsigned int ar_flags; 62 voff_t ar_lastoff; 63 struct vm_page *ar_pages[16]; /* XXX tune */ 64 }; 65 66 void uvm_page_array_init(struct uvm_page_array *, struct uvm_object *, 67 unsigned int); 68 void uvm_page_array_fini(struct uvm_page_array *); 69 void uvm_page_array_clear(struct uvm_page_array *); 70 struct vm_page *uvm_page_array_peek(struct uvm_page_array *); 71 void uvm_page_array_advance(struct uvm_page_array *); 72 int uvm_page_array_fill(struct uvm_page_array *, voff_t, unsigned int); 73 struct vm_page *uvm_page_array_fill_and_peek(struct uvm_page_array *, 74 voff_t, unsigned int); 75 76 /* 77 * flags for uvm_page_array_fill and uvm_page_array_fill_and_peek 78 */ 79 #define UVM_PAGE_ARRAY_FILL_DIRTY 1 /* dirty pages */ 80 #define UVM_PAGE_ARRAY_FILL_WRITEBACK 2 /* dirty or written-back */ 81 #define UVM_PAGE_ARRAY_FILL_DENSE 4 /* stop on a hole */ 82 #define UVM_PAGE_ARRAY_FILL_BACKWARD 8 /* descend order */ 83 84 #endif /* defined(_UVM_UVM_ARRAY_H_) */ 85