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 $ 40 * $DragonFly: src/sys/sys/buf2.h,v 1.18 2006/05/20 02:42:13 dillon Exp $ 41 */ 42 43 #ifndef _SYS_BUF2_H_ 44 #define _SYS_BUF2_H_ 45 46 #ifdef _KERNEL 47 48 #ifndef _SYS_BUF_H_ 49 #include <sys/buf.h> /* crit_*() functions */ 50 #endif 51 #ifndef _SYS_GLOBALDATA_H_ 52 #include <sys/globaldata.h> /* curthread */ 53 #endif 54 #ifndef _SYS_THREAD2_H_ 55 #include <sys/thread2.h> /* crit_*() functions */ 56 #endif 57 #ifndef _SYS_SPINLOCK2_H_ 58 #include <sys/spinlock2.h> /* crit_*() functions */ 59 #endif 60 61 /* 62 * Initialize a lock. 63 */ 64 #define BUF_LOCKINIT(bp) \ 65 lockinit(&(bp)->b_lock, buf_wmesg, 0, 0) 66 67 /* 68 * 69 * Get a lock sleeping non-interruptably until it becomes available. 70 * 71 * XXX lk_wmesg can race, but should not result in any operational issues. 72 */ 73 static __inline int 74 BUF_LOCK(struct buf *bp, int locktype) 75 { 76 bp->b_lock.lk_wmesg = buf_wmesg; 77 return (lockmgr(&(bp)->b_lock, locktype)); 78 } 79 /* 80 * Get a lock sleeping with specified interruptably and timeout. 81 * 82 * XXX lk_timo can race against other entities calling BUF_TIMELOCK, 83 * but will not interfere with entities calling BUF_LOCK since LK_TIMELOCK 84 * will not be set in that case. 85 * 86 * XXX lk_wmesg can race, but should not result in any operational issues. 87 */ 88 static __inline int 89 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int timo) 90 { 91 bp->b_lock.lk_wmesg = wmesg; 92 bp->b_lock.lk_timo = timo; 93 return (lockmgr(&(bp)->b_lock, locktype | LK_TIMELOCK)); 94 } 95 /* 96 * Release a lock. Only the acquiring process may free the lock unless 97 * it has been handed off to biodone. 98 */ 99 static __inline void 100 BUF_UNLOCK(struct buf *bp) 101 { 102 lockmgr(&(bp)->b_lock, LK_RELEASE); 103 } 104 105 /* 106 * When initiating asynchronous I/O, change ownership of the lock to the 107 * kernel. Once done, the lock may legally released by biodone. The 108 * original owning process can no longer acquire it recursively, but must 109 * wait until the I/O is completed and the lock has been freed by biodone. 110 */ 111 static __inline void 112 BUF_KERNPROC(struct buf *bp) 113 { 114 lockmgr_kernproc(&(bp)->b_lock); 115 } 116 /* 117 * Find out the number of references to a lock. 118 * 119 * The non-blocking version should only be used for assertions in cases 120 * where the buffer is expected to be owned or otherwise data stable. 121 */ 122 static __inline int 123 BUF_REFCNT(struct buf *bp) 124 { 125 return (lockcount(&(bp)->b_lock)); 126 } 127 128 static __inline int 129 BUF_REFCNTNB(struct buf *bp) 130 { 131 return (lockcountnb(&(bp)->b_lock)); 132 } 133 134 /* 135 * Free a buffer lock. 136 */ 137 #define BUF_LOCKFREE(bp) \ 138 if (BUF_REFCNTNB(bp) > 0) \ 139 panic("free locked buf") 140 141 static __inline void 142 bioq_init(struct bio_queue_head *head) 143 { 144 TAILQ_INIT(&head->queue); 145 head->last_offset = 0; 146 head->insert_point = NULL; 147 head->switch_point = NULL; 148 } 149 150 static __inline void 151 bioq_insert_tail(struct bio_queue_head *head, struct bio *bio) 152 { 153 if ((bio->bio_buf->b_flags & B_ORDERED) != 0) { 154 head->insert_point = bio; 155 head->switch_point = NULL; 156 } 157 TAILQ_INSERT_TAIL(&head->queue, bio, bio_act); 158 } 159 160 static __inline void 161 bioq_remove(struct bio_queue_head *head, struct bio *bio) 162 { 163 if (bio == head->switch_point) 164 head->switch_point = TAILQ_NEXT(bio, bio_act); 165 if (bio == head->insert_point) { 166 head->insert_point = TAILQ_PREV(bio, bio_queue, bio_act); 167 if (head->insert_point == NULL) 168 head->last_offset = 0; 169 } else if (bio == TAILQ_FIRST(&head->queue)) 170 head->last_offset = bio->bio_offset; 171 TAILQ_REMOVE(&head->queue, bio, bio_act); 172 if (TAILQ_FIRST(&head->queue) == head->switch_point) 173 head->switch_point = NULL; 174 } 175 176 static __inline struct bio * 177 bioq_first(struct bio_queue_head *head) 178 { 179 return (TAILQ_FIRST(&head->queue)); 180 } 181 182 #endif /* _KERNEL */ 183 184 #endif /* !_SYS_BUF2_H_ */ 185