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 1.6 2003/08/20 07:31:21 rob 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 int s, ret; 67 68 s = splbio(); 69 lwkt_gettoken(&buftimetoken); 70 locktype |= LK_INTERLOCK; 71 bp->b_lock.lk_wmesg = buf_wmesg; 72 bp->b_lock.lk_prio = 0; /* tsleep flags */ 73 /* bp->b_lock.lk_timo = 0; not necessary */ 74 ret = lockmgr(&(bp)->b_lock, locktype, &buftimetoken, curthread); 75 splx(s); 76 return ret; 77 } 78 /* 79 * Get a lock sleeping with specified interruptably and timeout. 80 */ 81 static __inline int BUF_TIMELOCK (struct buf *, int, char *, int, int); 82 static __inline int 83 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int catch, int timo) 84 { 85 int s, ret; 86 87 s = splbio(); 88 lwkt_gettoken(&buftimetoken); 89 locktype |= LK_INTERLOCK | LK_TIMELOCK; 90 bp->b_lock.lk_wmesg = wmesg; 91 bp->b_lock.lk_prio = catch; /* tsleep flags */ 92 bp->b_lock.lk_timo = timo; 93 ret = lockmgr(&(bp)->b_lock, (locktype), &buftimetoken, curthread); 94 splx(s); 95 return ret; 96 } 97 /* 98 * Release a lock. Only the acquiring process may free the lock unless 99 * it has been handed off to biodone. 100 */ 101 static __inline void BUF_UNLOCK (struct buf *); 102 static __inline void 103 BUF_UNLOCK(struct buf *bp) 104 { 105 int s; 106 107 s = splbio(); 108 lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curthread); 109 splx(s); 110 } 111 112 /* 113 * Free a buffer lock. 114 */ 115 #define BUF_LOCKFREE(bp) \ 116 if (BUF_REFCNT(bp) > 0) \ 117 panic("free locked buf") 118 /* 119 * When initiating asynchronous I/O, change ownership of the lock to the 120 * kernel. Once done, the lock may legally released by biodone. The 121 * original owning process can no longer acquire it recursively, but must 122 * wait until the I/O is completed and the lock has been freed by biodone. 123 */ 124 static __inline void BUF_KERNPROC (struct buf *); 125 static __inline void 126 BUF_KERNPROC(struct buf *bp) 127 { 128 struct thread *td = curthread; 129 130 if (bp->b_lock.lk_lockholder == td) 131 td->td_locks--; 132 bp->b_lock.lk_lockholder = LK_KERNTHREAD; 133 } 134 /* 135 * Find out the number of references to a lock. 136 */ 137 static __inline int BUF_REFCNT (struct buf *); 138 static __inline int 139 BUF_REFCNT(struct buf *bp) 140 { 141 int s, ret; 142 143 s = splbio(); 144 ret = lockcount(&(bp)->b_lock); 145 splx(s); 146 return ret; 147 } 148 149 static __inline void 150 bufq_init(struct buf_queue_head *head) 151 { 152 TAILQ_INIT(&head->queue); 153 head->last_pblkno = 0; 154 head->insert_point = NULL; 155 head->switch_point = NULL; 156 } 157 158 static __inline void 159 bufq_insert_tail(struct buf_queue_head *head, struct buf *bp) 160 { 161 if ((bp->b_flags & B_ORDERED) != 0) { 162 head->insert_point = bp; 163 head->switch_point = NULL; 164 } 165 TAILQ_INSERT_TAIL(&head->queue, bp, b_act); 166 } 167 168 static __inline void 169 bufq_remove(struct buf_queue_head *head, struct buf *bp) 170 { 171 if (bp == head->switch_point) 172 head->switch_point = TAILQ_NEXT(bp, b_act); 173 if (bp == head->insert_point) { 174 head->insert_point = TAILQ_PREV(bp, buf_queue, b_act); 175 if (head->insert_point == NULL) 176 head->last_pblkno = 0; 177 } else if (bp == TAILQ_FIRST(&head->queue)) 178 head->last_pblkno = bp->b_pblkno; 179 TAILQ_REMOVE(&head->queue, bp, b_act); 180 if (TAILQ_FIRST(&head->queue) == head->switch_point) 181 head->switch_point = NULL; 182 } 183 184 static __inline struct buf * 185 bufq_first(struct buf_queue_head *head) 186 { 187 return (TAILQ_FIRST(&head->queue)); 188 } 189 190 #endif /* _KERNEL */ 191 192 #endif /* !_SYS_BUF2_H_ */ 193