FreeBSD/Linux Kernel Cross Reference
sys/sys/bufobj.h
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: src/sys/sys/bufobj.h,v 1.21 2008/10/10 21:23:50 attilio Exp $
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 be 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 #include <sys/_lock.h>
56 #include <sys/_mutex.h>
57
58 struct bufobj;
59 struct buf_ops;
60
61 extern struct buf_ops buf_ops_bio;
62
63 TAILQ_HEAD(buflists, buf);
64
65 /* A Buffer splay list */
66 struct bufv {
67 struct buflists bv_hd; /* Sorted blocklist */
68 struct buf *bv_root; /* Buf splay tree */
69 int bv_cnt; /* Number of buffers */
70 };
71
72 typedef void b_strategy_t(struct bufobj *, struct buf *);
73 typedef int b_write_t(struct buf *);
74 typedef int b_sync_t(struct bufobj *, int waitfor);
75 typedef void b_bdflush_t(struct bufobj *, struct buf *);
76
77 struct buf_ops {
78 char *bop_name;
79 b_write_t *bop_write;
80 b_strategy_t *bop_strategy;
81 b_sync_t *bop_sync;
82 b_bdflush_t *bop_bdflush;
83 };
84
85 #define BO_STRATEGY(bo, bp) ((bo)->bo_ops->bop_strategy((bo), (bp)))
86 #define BO_SYNC(bo, w) ((bo)->bo_ops->bop_sync((bo), (w)))
87 #define BO_WRITE(bo, bp) ((bo)->bo_ops->bop_write((bp)))
88 #define BO_BDFLUSH(bo, bp) ((bo)->bo_ops->bop_bdflush((bo), (bp)))
89
90 struct bufobj {
91 struct mtx bo_mtx; /* Mutex which protects "i" things */
92 struct bufv bo_clean; /* i Clean buffers */
93 struct bufv bo_dirty; /* i Dirty buffers */
94 long bo_numoutput; /* i Writes in progress */
95 u_int bo_flag; /* i Flags */
96 struct buf_ops *bo_ops; /* - Buffer operations */
97 int bo_bsize; /* - Block size for i/o */
98 struct vm_object *bo_object; /* v Place to store VM object */
99 LIST_ENTRY(bufobj) bo_synclist; /* S dirty vnode list */
100 void *bo_private; /* private pointer */
101 struct vnode *__bo_vnode; /*
102 * XXX: This vnode pointer is here
103 * XXX: only to keep the syncer working
104 * XXX: for now.
105 */
106 };
107
108 /*
109 * XXX BO_ONWORKLST could be replaced with a check for NULL list elements
110 * in v_synclist.
111 */
112 #define BO_ONWORKLST (1 << 0) /* On syncer work-list */
113 #define BO_WWAIT (1 << 1) /* Wait for output to complete */
114 #define BO_NEEDSGIANT (1 << 2) /* Require giant for child buffers. */
115
116 #define BO_MTX(bo) (&(bo)->bo_mtx)
117 #define BO_LOCK(bo) mtx_lock(BO_MTX((bo)))
118 #define BO_UNLOCK(bo) mtx_unlock(BO_MTX((bo)))
119 #define ASSERT_BO_LOCKED(bo) mtx_assert(BO_MTX((bo)), MA_OWNED)
120 #define ASSERT_BO_UNLOCKED(bo) mtx_assert(BO_MTX((bo)), MA_NOTOWNED)
121
122 void bufobj_wdrop(struct bufobj *bo);
123 void bufobj_wref(struct bufobj *bo);
124 void bufobj_wrefl(struct bufobj *bo);
125 int bufobj_invalbuf(struct bufobj *bo, int flags, int slpflag, int slptimeo);
126 int bufobj_wwait(struct bufobj *bo, int slpflag, int timeo);
127 int bufsync(struct bufobj *bo, int waitfor);
128 void bufbdflush(struct bufobj *bo, struct buf *bp);
129
130 #endif /* defined(_KERNEL) || defined(_KVM_VNODE) */
131 #endif /* _SYS_BUFOBJ_H_ */
132
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