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 1.7 2004/03/01 06:33:19 dillon Exp $ 41 */ 42 43 #ifndef _SYS_BUF2_H_ 44 #define _SYS_BUF2_H_ 45 46 #ifdef _KERNEL 47 48 #ifndef _SYS_GLOBALDATA_H_ 49 #include <sys/globaldata.h> /* curthread */ 50 #endif 51 52 /* 53 * Initialize a lock. 54 */ 55 #define BUF_LOCKINIT(bp) \ 56 lockinit(&(bp)->b_lock, 0, buf_wmesg, 0, 0) 57 58 /* 59 * 60 * Get a lock sleeping non-interruptably until it becomes available. 61 */ 62 static __inline int BUF_LOCK (struct buf *, int); 63 static __inline int 64 BUF_LOCK(struct buf *bp, int locktype) 65 { 66 lwkt_tokref ilock; 67 int s, ret; 68 69 s = splbio(); 70 lwkt_gettoken(&ilock, &buftimetoken); 71 locktype |= LK_INTERLOCK; 72 bp->b_lock.lk_wmesg = buf_wmesg; 73 bp->b_lock.lk_prio = 0; /* tsleep flags */ 74 /* bp->b_lock.lk_timo = 0; not necessary */ 75 ret = lockmgr(&(bp)->b_lock, locktype, &ilock, curthread); 76 splx(s); 77 return ret; 78 } 79 /* 80 * Get a lock sleeping with specified interruptably and timeout. 81 */ 82 static __inline int BUF_TIMELOCK (struct buf *, int, char *, int, int); 83 static __inline int 84 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int catch, int timo) 85 { 86 lwkt_tokref ilock; 87 int s, ret; 88 89 s = splbio(); 90 lwkt_gettoken(&ilock, &buftimetoken); 91 locktype |= LK_INTERLOCK | LK_TIMELOCK; 92 bp->b_lock.lk_wmesg = wmesg; 93 bp->b_lock.lk_prio = catch; /* tsleep flags */ 94 bp->b_lock.lk_timo = timo; 95 ret = lockmgr(&(bp)->b_lock, locktype, &ilock, curthread); 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 */ 103 static __inline void BUF_UNLOCK (struct buf *); 104 static __inline void 105 BUF_UNLOCK(struct buf *bp) 106 { 107 int s; 108 109 s = splbio(); 110 lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curthread); 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 */ 126 static __inline void BUF_KERNPROC (struct buf *); 127 static __inline void 128 BUF_KERNPROC(struct buf *bp) 129 { 130 struct thread *td = curthread; 131 132 if (bp->b_lock.lk_lockholder == td) 133 td->td_locks--; 134 bp->b_lock.lk_lockholder = LK_KERNTHREAD; 135 } 136 /* 137 * Find out the number of references to a lock. 138 */ 139 static __inline int BUF_REFCNT (struct buf *); 140 static __inline int 141 BUF_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 } 150 151 static __inline void 152 bufq_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 } 159 160 static __inline void 161 bufq_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 } 169 170 static __inline void 171 bufq_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 } 185 186 static __inline struct buf * 187 bufq_first(struct buf_queue_head *head) 188 { 189 return (TAILQ_FIRST(&head->queue)); 190 } 191 192 #endif /* _KERNEL */ 193 194 #endif /* !_SYS_BUF2_H_ */ 195