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 1.9 2004/11/12 00:09:27 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 63 BUF_LOCK(struct buf *bp, int locktype) 64 { 65 lwkt_tokref ilock; 66 int s, ret; 67 68 s = splbio(); 69 lwkt_gettoken(&ilock, &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, &ilock, curthread); 75 splx(s); 76 return ret; 77 } 78 /* 79 * Get a lock sleeping with specified interruptably and timeout. 80 */ 81 static __inline int 82 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int catch, int timo) 83 { 84 lwkt_tokref ilock; 85 int s, ret; 86 87 s = splbio(); 88 lwkt_gettoken(&ilock, &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, &ilock, 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 102 BUF_UNLOCK(struct buf *bp) 103 { 104 int s; 105 106 s = splbio(); 107 lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curthread); 108 splx(s); 109 } 110 111 /* 112 * When initiating asynchronous I/O, change ownership of the lock to the 113 * kernel. Once done, the lock may legally released by biodone. The 114 * original owning process can no longer acquire it recursively, but must 115 * wait until the I/O is completed and the lock has been freed by biodone. 116 */ 117 static __inline void 118 BUF_KERNPROC(struct buf *bp) 119 { 120 struct thread *td = curthread; 121 122 if (bp->b_lock.lk_lockholder == td) 123 td->td_locks--; 124 bp->b_lock.lk_lockholder = LK_KERNTHREAD; 125 } 126 /* 127 * Find out the number of references to a lock. 128 * 129 * The non-blocking version should only be used for assertions in cases 130 * where the buffer is expected to be owned or otherwise data stable. 131 */ 132 static __inline int 133 BUF_REFCNT(struct buf *bp) 134 { 135 int s, ret; 136 137 s = splbio(); 138 ret = lockcount(&(bp)->b_lock); 139 splx(s); 140 return ret; 141 } 142 143 static __inline int 144 BUF_REFCNTNB(struct buf *bp) 145 { 146 return (lockcountnb(&(bp)->b_lock)); 147 } 148 149 /* 150 * Free a buffer lock. 151 */ 152 #define BUF_LOCKFREE(bp) \ 153 if (BUF_REFCNTNB(bp) > 0) \ 154 panic("free locked buf") 155 156 static __inline void 157 bufq_init(struct buf_queue_head *head) 158 { 159 TAILQ_INIT(&head->queue); 160 head->last_pblkno = 0; 161 head->insert_point = NULL; 162 head->switch_point = NULL; 163 } 164 165 static __inline void 166 bufq_insert_tail(struct buf_queue_head *head, struct buf *bp) 167 { 168 if ((bp->b_flags & B_ORDERED) != 0) { 169 head->insert_point = bp; 170 head->switch_point = NULL; 171 } 172 TAILQ_INSERT_TAIL(&head->queue, bp, b_act); 173 } 174 175 static __inline void 176 bufq_remove(struct buf_queue_head *head, struct buf *bp) 177 { 178 if (bp == head->switch_point) 179 head->switch_point = TAILQ_NEXT(bp, b_act); 180 if (bp == head->insert_point) { 181 head->insert_point = TAILQ_PREV(bp, buf_queue, b_act); 182 if (head->insert_point == NULL) 183 head->last_pblkno = 0; 184 } else if (bp == TAILQ_FIRST(&head->queue)) 185 head->last_pblkno = bp->b_pblkno; 186 TAILQ_REMOVE(&head->queue, bp, b_act); 187 if (TAILQ_FIRST(&head->queue) == head->switch_point) 188 head->switch_point = NULL; 189 } 190 191 static __inline struct buf * 192 bufq_first(struct buf_queue_head *head) 193 { 194 return (TAILQ_FIRST(&head->queue)); 195 } 196 197 #endif /* _KERNEL */ 198 199 #endif /* !_SYS_BUF2_H_ */ 200