Change sendfile() to use the new m_ext callback scheme for cleaning up after
[dragonfly.git] / sys / sys / buf2.h
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1/*
2 * Copyright (c) 1982, 1986, 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 * (c) UNIX System Laboratories, Inc.
5 * All or some portions of this file are derived from material licensed
6 * to the University of California by American Telephone and Telegraph
7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8 * the permission of UNIX System Laboratories, Inc.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by the University of
21 * California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)buf.h 8.9 (Berkeley) 3/30/95
39 * $FreeBSD: src/sys/sys/buf.h,v 1.88.2.10 2003/01/25 19:02:23 dillon Exp $
41a01a4d 40 * $DragonFly: src/sys/sys/buf2.h,v 1.7 2004/03/01 06:33:19 dillon Exp $
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41 */
42
43#ifndef _SYS_BUF2_H_
44#define _SYS_BUF2_H_
45
46#ifdef _KERNEL
47
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48#ifndef _SYS_GLOBALDATA_H_
49#include <sys/globaldata.h> /* curthread */
50#endif
51
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52/*
53 * Initialize a lock.
54 */
55#define BUF_LOCKINIT(bp) \
377d4740 56 lockinit(&(bp)->b_lock, 0, buf_wmesg, 0, 0)
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57
58/*
59 *
60 * Get a lock sleeping non-interruptably until it becomes available.
61 */
b153f746 62static __inline int BUF_LOCK (struct buf *, int);
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63static __inline int
64BUF_LOCK(struct buf *bp, int locktype)
65{
41a01a4d 66 lwkt_tokref ilock;
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67 int s, ret;
68
69 s = splbio();
41a01a4d 70 lwkt_gettoken(&ilock, &buftimetoken);
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71 locktype |= LK_INTERLOCK;
72 bp->b_lock.lk_wmesg = buf_wmesg;
377d4740 73 bp->b_lock.lk_prio = 0; /* tsleep flags */
3020e3be 74 /* bp->b_lock.lk_timo = 0; not necessary */
41a01a4d 75 ret = lockmgr(&(bp)->b_lock, locktype, &ilock, curthread);
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76 splx(s);
77 return ret;
78}
79/*
80 * Get a lock sleeping with specified interruptably and timeout.
81 */
b153f746 82static __inline int BUF_TIMELOCK (struct buf *, int, char *, int, int);
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83static __inline int
84BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int catch, int timo)
85{
41a01a4d 86 lwkt_tokref ilock;
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87 int s, ret;
88
89 s = splbio();
41a01a4d 90 lwkt_gettoken(&ilock, &buftimetoken);
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91 locktype |= LK_INTERLOCK | LK_TIMELOCK;
92 bp->b_lock.lk_wmesg = wmesg;
377d4740 93 bp->b_lock.lk_prio = catch; /* tsleep flags */
3020e3be 94 bp->b_lock.lk_timo = timo;
41a01a4d 95 ret = lockmgr(&(bp)->b_lock, locktype, &ilock, curthread);
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96 splx(s);
97 return ret;
98}
99/*
100 * Release a lock. Only the acquiring process may free the lock unless
101 * it has been handed off to biodone.
102 */
b153f746 103static __inline void BUF_UNLOCK (struct buf *);
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104static __inline void
105BUF_UNLOCK(struct buf *bp)
106{
107 int s;
108
109 s = splbio();
dadab5e9 110 lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curthread);
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111 splx(s);
112}
113
114/*
115 * Free a buffer lock.
116 */
117#define BUF_LOCKFREE(bp) \
118 if (BUF_REFCNT(bp) > 0) \
119 panic("free locked buf")
120/*
121 * When initiating asynchronous I/O, change ownership of the lock to the
122 * kernel. Once done, the lock may legally released by biodone. The
123 * original owning process can no longer acquire it recursively, but must
124 * wait until the I/O is completed and the lock has been freed by biodone.
125 */
b153f746 126static __inline void BUF_KERNPROC (struct buf *);
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127static __inline void
128BUF_KERNPROC(struct buf *bp)
129{
dadab5e9 130 struct thread *td = curthread;
3020e3be 131
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132 if (bp->b_lock.lk_lockholder == td)
133 td->td_locks--;
134 bp->b_lock.lk_lockholder = LK_KERNTHREAD;
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135}
136/*
137 * Find out the number of references to a lock.
138 */
b153f746 139static __inline int BUF_REFCNT (struct buf *);
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140static __inline int
141BUF_REFCNT(struct buf *bp)
142{
143 int s, ret;
144
145 s = splbio();
146 ret = lockcount(&(bp)->b_lock);
147 splx(s);
148 return ret;
149}
150
151static __inline void
152bufq_init(struct buf_queue_head *head)
153{
154 TAILQ_INIT(&head->queue);
155 head->last_pblkno = 0;
156 head->insert_point = NULL;
157 head->switch_point = NULL;
158}
159
160static __inline void
161bufq_insert_tail(struct buf_queue_head *head, struct buf *bp)
162{
163 if ((bp->b_flags & B_ORDERED) != 0) {
164 head->insert_point = bp;
165 head->switch_point = NULL;
166 }
167 TAILQ_INSERT_TAIL(&head->queue, bp, b_act);
168}
169
170static __inline void
171bufq_remove(struct buf_queue_head *head, struct buf *bp)
172{
173 if (bp == head->switch_point)
174 head->switch_point = TAILQ_NEXT(bp, b_act);
175 if (bp == head->insert_point) {
176 head->insert_point = TAILQ_PREV(bp, buf_queue, b_act);
177 if (head->insert_point == NULL)
178 head->last_pblkno = 0;
179 } else if (bp == TAILQ_FIRST(&head->queue))
180 head->last_pblkno = bp->b_pblkno;
181 TAILQ_REMOVE(&head->queue, bp, b_act);
182 if (TAILQ_FIRST(&head->queue) == head->switch_point)
183 head->switch_point = NULL;
184}
185
186static __inline struct buf *
187bufq_first(struct buf_queue_head *head)
188{
189 return (TAILQ_FIRST(&head->queue));
190}
191
192#endif /* _KERNEL */
193
194#endif /* !_SYS_BUF2_H_ */