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: releng/6.0/sys/sys/bufobj.h 147280 2005-06-10 23:50:41Z green $
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
56 struct bufobj;
57 struct buf_ops;
58
59 extern struct buf_ops buf_ops_bio;
60
61 TAILQ_HEAD(buflists, buf);
62
63 /* A Buffer splay list */
64 struct 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
70 typedef void b_strategy_t(struct bufobj *, struct buf *);
71 typedef int b_write_t(struct buf *);
72 typedef int b_sync_t(struct bufobj *, int waitfor, struct thread *td);
73
74 struct buf_ops {
75 char *bop_name;
76 b_write_t *bop_write;
77 b_strategy_t *bop_strategy;
78 b_sync_t *bop_sync;
79 };
80
81 #define BO_STRATEGY(bo, bp) ((bo)->bo_ops->bop_strategy((bo), (bp)))
82 #define BO_SYNC(bo, w, td) ((bo)->bo_ops->bop_sync((bo), (w), (td)))
83 #define BO_WRITE(bo, bp) ((bo)->bo_ops->bop_write((bp)))
84
85 struct bufobj {
86 struct mtx *bo_mtx; /* Mutex which protects "i" things */
87 struct bufv bo_clean; /* i Clean buffers */
88 struct bufv bo_dirty; /* i Dirty buffers */
89 long bo_numoutput; /* i Writes in progress */
90 u_int bo_flag; /* i Flags */
91 struct buf_ops *bo_ops; /* - Buffer operations */
92 int bo_bsize; /* - Block size for i/o */
93 struct vm_object *bo_object; /* v Place to store VM object */
94 LIST_ENTRY(bufobj) bo_synclist; /* S dirty vnode list */
95 void *bo_private; /* private pointer */
96 struct vnode *__bo_vnode; /*
97 * XXX: This vnode pointer is here
98 * XXX: only to keep the syncer working
99 * XXX: for now.
100 */
101 };
102
103 /*
104 * XXX BO_ONWORKLST could be replaced with a check for NULL list elements
105 * in v_synclist.
106 */
107 #define BO_ONWORKLST (1 << 0) /* On syncer work-list */
108 #define BO_WWAIT (1 << 1) /* Wait for output to complete */
109
110 #define BO_LOCK(bo) \
111 do { \
112 KASSERT((bo)->bo_mtx != NULL, ("No lock in bufobj")); \
113 mtx_lock((bo)->bo_mtx); \
114 } while (0)
115
116 #define BO_UNLOCK(bo) \
117 do { \
118 KASSERT((bo)->bo_mtx != NULL, ("No lock in bufobj")); \
119 mtx_unlock((bo)->bo_mtx); \
120 } while (0)
121
122 #define BO_MTX(bo) ((bo)->bo_mtx)
123 #define ASSERT_BO_LOCKED(bo) mtx_assert(bo->bo_mtx, MA_OWNED)
124 #define ASSERT_BO_UNLOCKED(bo) mtx_assert(bo->bo_mtx, MA_NOTOWNED)
125
126 void bufobj_wdrop(struct bufobj *bo);
127 void bufobj_wref(struct bufobj *bo);
128 void bufobj_wrefl(struct bufobj *bo);
129 int bufobj_invalbuf(struct bufobj *bo, int flags, struct thread *td, int slpflag, int slptimeo);
130 int bufobj_wwait(struct bufobj *bo, int slpflag, int timeo);
131 int bufsync(struct bufobj *bo, int waitfor, struct thread *td);
132
133 #endif /* defined(_KERNEL) || defined(_KVM_VNODE) */
134 #endif /* _SYS_BUFOBJ_H_ */
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