bufobj.h revision 136966
1/*- 2 * Copyright (c) 2004 Poul-Henning Kamp 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: head/sys/sys/bufobj.h 136966 2004-10-26 07:39:12Z phk $ 27 */ 28 29/* 30 * Architectural notes: 31 * 32 * bufobj is a new object which is what buffers hang from in the buffer 33 * cache. 34 * 35 * This used to be vnodes, but we need non-vnode code to be able 36 * to use the buffer cache as well, specifically geom classes like gbde, 37 * raid3 and raid5. 38 * 39 * All vnodes will contain a bufobj initially, but down the road we may 40 * want to only allocate bufobjs when they are needed. There could be a 41 * large number of vnodes in the system which wouldn't need a bufobj during 42 * their lifetime. 43 * 44 * The exact relationship to the vmobject is not determined at this point, 45 * it may in fact bee that we find them to be two sides of the same object 46 * once things starts to crystalize. 47 */ 48 49#ifndef _SYS_BUFOBJ_H_ 50#define _SYS_BUFOBJ_H_ 51 52#if defined(_KERNEL) || defined(_KVM_VNODE) 53 54#include <sys/queue.h> 55 56struct bufobj; 57struct buf_ops; 58 59extern struct buf_ops buf_ops_bio; 60 61TAILQ_HEAD(buflists, buf); 62 63/* A Buffer splay list */ 64struct bufv { 65 struct buflists bv_hd; /* Sorted blocklist */ 66 struct buf *bv_root; /* Buf splay tree */ 67 int bv_cnt; /* Number of buffers */ 68}; 69 70typedef void b_strategy_t(struct bufobj *, struct buf *); 71typedef int b_write_t(struct buf *); 72 73struct buf_ops { 74 char *bop_name; 75 b_write_t *bop_write; 76 b_strategy_t *bop_strategy; 77}; 78 79struct bufobj { 80 struct mtx *bo_mtx; /* Mutex which protects "i" things */ 81 struct bufv bo_clean; /* i Clean buffers */ 82 struct bufv bo_dirty; /* i Dirty buffers */ 83 long bo_numoutput; /* i Writes in progress */ 84 u_int bo_flag; /* i Flags */ 85 struct buf_ops *bo_ops; /* - Buffer operations */ 86 int bo_bsize; /* - Block size for i/o */ 87 struct vm_object *bo_object; /* v Place to store VM object */ 88}; 89 90#define BO_WWAIT (1 << 1) /* Wait for output to complete */ 91 92#define BO_LOCK(bo) \ 93 do { \ 94 KASSERT (bo->bo_mtx != NULL, ("No lock in bufobj")); \ 95 mtx_lock((bo)->bo_mtx); \ 96 } while (0) 97 98#define BO_UNLOCK(bo) \ 99 do { \ 100 KASSERT (bo->bo_mtx != NULL, ("No lock in bufobj")); \ 101 mtx_unlock((bo)->bo_mtx); \ 102 } while (0) 103 104#define BO_MTX(bo) ((bo)->bo_mtx) 105#define ASSERT_BO_LOCKED(bo) mtx_assert(bo->bo_mtx, MA_OWNED) 106#define ASSERT_BO_UNLOCKED(bo) mtx_assert(bo->bo_mtx, MA_NOTOWNED) 107 108void bufobj_wdrop(struct bufobj *bo); 109void bufobj_wref(struct bufobj *bo); 110int bufobj_wwait(struct bufobj *bo, int slpflag, int timeo); 111 112#endif /* defined(_KERNEL) || defined(_KVM_VNODE) */ 113#endif /* _SYS_BUFOBJ_H_ */ 114 115 116