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 1.10 2005/06/10 23:59:33 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 #ifndef _SYS_THREAD2_H_ 53 #include <sys/thread2.h> /* crit_*() functions */ 54 #endif 55 56 /* 57 * Initialize a lock. 58 */ 59 #define BUF_LOCKINIT(bp) \ 60 lockinit(&(bp)->b_lock, 0, buf_wmesg, 0, 0) 61 62 /* 63 * 64 * Get a lock sleeping non-interruptably until it becomes available. 65 */ 66 static __inline int 67 BUF_LOCK(struct buf *bp, int locktype) 68 { 69 lwkt_tokref ilock; 70 int ret; 71 72 crit_enter(); 73 lwkt_gettoken(&ilock, &buftimetoken); 74 locktype |= LK_INTERLOCK; 75 bp->b_lock.lk_wmesg = buf_wmesg; 76 bp->b_lock.lk_prio = 0; /* tsleep flags */ 77 /* bp->b_lock.lk_timo = 0; not necessary */ 78 ret = lockmgr(&(bp)->b_lock, locktype, &ilock, curthread); 79 crit_exit(); 80 return ret; 81 } 82 /* 83 * Get a lock sleeping with specified interruptably and timeout. 84 */ 85 static __inline int 86 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int catch, int timo) 87 { 88 lwkt_tokref ilock; 89 int ret; 90 91 crit_enter(); 92 lwkt_gettoken(&ilock, &buftimetoken); 93 locktype |= LK_INTERLOCK | LK_TIMELOCK; 94 bp->b_lock.lk_wmesg = wmesg; 95 bp->b_lock.lk_prio = catch; /* tsleep flags */ 96 bp->b_lock.lk_timo = timo; 97 ret = lockmgr(&(bp)->b_lock, locktype, &ilock, curthread); 98 crit_exit(); 99 return ret; 100 } 101 /* 102 * Release a lock. Only the acquiring process may free the lock unless 103 * it has been handed off to biodone. 104 */ 105 static __inline void 106 BUF_UNLOCK(struct buf *bp) 107 { 108 crit_enter(); 109 lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curthread); 110 crit_exit(); 111 } 112 113 /* 114 * When initiating asynchronous I/O, change ownership of the lock to the 115 * kernel. Once done, the lock may legally released by biodone. The 116 * original owning process can no longer acquire it recursively, but must 117 * wait until the I/O is completed and the lock has been freed by biodone. 118 */ 119 static __inline void 120 BUF_KERNPROC(struct buf *bp) 121 { 122 struct thread *td = curthread; 123 124 if (bp->b_lock.lk_lockholder == td) 125 td->td_locks--; 126 bp->b_lock.lk_lockholder = LK_KERNTHREAD; 127 } 128 /* 129 * Find out the number of references to a lock. 130 * 131 * The non-blocking version should only be used for assertions in cases 132 * where the buffer is expected to be owned or otherwise data stable. 133 */ 134 static __inline int 135 BUF_REFCNT(struct buf *bp) 136 { 137 int ret; 138 139 crit_enter(); 140 ret = lockcount(&(bp)->b_lock); 141 crit_exit(); 142 return ret; 143 } 144 145 static __inline int 146 BUF_REFCNTNB(struct buf *bp) 147 { 148 return (lockcountnb(&(bp)->b_lock)); 149 } 150 151 /* 152 * Free a buffer lock. 153 */ 154 #define BUF_LOCKFREE(bp) \ 155 if (BUF_REFCNTNB(bp) > 0) \ 156 panic("free locked buf") 157 158 static __inline void 159 bufq_init(struct buf_queue_head *head) 160 { 161 TAILQ_INIT(&head->queue); 162 head->last_pblkno = 0; 163 head->insert_point = NULL; 164 head->switch_point = NULL; 165 } 166 167 static __inline void 168 bufq_insert_tail(struct buf_queue_head *head, struct buf *bp) 169 { 170 if ((bp->b_flags & B_ORDERED) != 0) { 171 head->insert_point = bp; 172 head->switch_point = NULL; 173 } 174 TAILQ_INSERT_TAIL(&head->queue, bp, b_act); 175 } 176 177 static __inline void 178 bufq_remove(struct buf_queue_head *head, struct buf *bp) 179 { 180 if (bp == head->switch_point) 181 head->switch_point = TAILQ_NEXT(bp, b_act); 182 if (bp == head->insert_point) { 183 head->insert_point = TAILQ_PREV(bp, buf_queue, b_act); 184 if (head->insert_point == NULL) 185 head->last_pblkno = 0; 186 } else if (bp == TAILQ_FIRST(&head->queue)) 187 head->last_pblkno = bp->b_pblkno; 188 TAILQ_REMOVE(&head->queue, bp, b_act); 189 if (TAILQ_FIRST(&head->queue) == head->switch_point) 190 head->switch_point = NULL; 191 } 192 193 static __inline struct buf * 194 bufq_first(struct buf_queue_head *head) 195 { 196 return (TAILQ_FIRST(&head->queue)); 197 } 198 199 #endif /* _KERNEL */ 200 201 #endif /* !_SYS_BUF2_H_ */ 202