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 1.14 2006/03/02 19:26:17 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 #ifndef _SYS_THREAD2_H_ 52 #include <sys/thread2.h> /* crit_*() functions */ 53 #endif 54 #ifndef _SYS_SPINLOCK2_H_ 55 #include <sys/spinlock2.h> /* crit_*() functions */ 56 #endif 57 58 /* 59 * Initialize a lock. 60 */ 61 #define BUF_LOCKINIT(bp) \ 62 lockinit(&(bp)->b_lock, buf_wmesg, 0, 0) 63 64 /* 65 * 66 * Get a lock sleeping non-interruptably until it becomes available. 67 * 68 * XXX lk_wmesg can race, but should not result in any operational issues. 69 */ 70 static __inline int 71 BUF_LOCK(struct buf *bp, int locktype) 72 { 73 bp->b_lock.lk_wmesg = buf_wmesg; 74 return (lockmgr(&(bp)->b_lock, locktype, NULL, curthread)); 75 } 76 /* 77 * Get a lock sleeping with specified interruptably and timeout. 78 * 79 * XXX lk_timo can race against other entities calling BUF_TIMELOCK, 80 * but will not interfere with entities calling BUF_LOCK since LK_TIMELOCK 81 * will not be set in that case. 82 * 83 * XXX lk_wmesg can race, but should not result in any operational issues. 84 */ 85 static __inline int 86 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int timo) 87 { 88 bp->b_lock.lk_wmesg = wmesg; 89 bp->b_lock.lk_timo = timo; 90 return (lockmgr(&(bp)->b_lock, locktype | LK_TIMELOCK, 91 NULL, curthread)); 92 } 93 /* 94 * Release a lock. Only the acquiring process may free the lock unless 95 * it has been handed off to biodone. 96 */ 97 static __inline void 98 BUF_UNLOCK(struct buf *bp) 99 { 100 lockmgr(&(bp)->b_lock, LK_RELEASE, NULL, curthread); 101 } 102 103 /* 104 * When initiating asynchronous I/O, change ownership of the lock to the 105 * kernel. Once done, the lock may legally released by biodone. The 106 * original owning process can no longer acquire it recursively, but must 107 * wait until the I/O is completed and the lock has been freed by biodone. 108 */ 109 static __inline void 110 BUF_KERNPROC(struct buf *bp) 111 { 112 struct thread *td = curthread; 113 114 if (bp->b_lock.lk_lockholder == td) 115 td->td_locks--; 116 bp->b_lock.lk_lockholder = LK_KERNTHREAD; 117 } 118 /* 119 * Find out the number of references to a lock. 120 * 121 * The non-blocking version should only be used for assertions in cases 122 * where the buffer is expected to be owned or otherwise data stable. 123 */ 124 static __inline int 125 BUF_REFCNT(struct buf *bp) 126 { 127 return (lockcount(&(bp)->b_lock)); 128 } 129 130 static __inline int 131 BUF_REFCNTNB(struct buf *bp) 132 { 133 return (lockcountnb(&(bp)->b_lock)); 134 } 135 136 /* 137 * Free a buffer lock. 138 */ 139 #define BUF_LOCKFREE(bp) \ 140 if (BUF_REFCNTNB(bp) > 0) \ 141 panic("free locked buf") 142 143 static __inline void 144 bioq_init(struct bio_queue_head *head) 145 { 146 TAILQ_INIT(&head->queue); 147 head->last_blkno = 0; 148 head->insert_point = NULL; 149 head->switch_point = NULL; 150 } 151 152 static __inline void 153 bioq_insert_tail(struct bio_queue_head *head, struct bio *bio) 154 { 155 if ((bio->bio_buf->b_flags & B_ORDERED) != 0) { 156 head->insert_point = bio; 157 head->switch_point = NULL; 158 } 159 TAILQ_INSERT_TAIL(&head->queue, bio, bio_act); 160 } 161 162 static __inline void 163 bioq_remove(struct bio_queue_head *head, struct bio *bio) 164 { 165 if (bio == head->switch_point) 166 head->switch_point = TAILQ_NEXT(bio, bio_act); 167 if (bio == head->insert_point) { 168 head->insert_point = TAILQ_PREV(bio, bio_queue, bio_act); 169 if (head->insert_point == NULL) 170 head->last_blkno = 0; 171 } else if (bio == TAILQ_FIRST(&head->queue)) 172 head->last_blkno = bio->bio_blkno; 173 TAILQ_REMOVE(&head->queue, bio, bio_act); 174 if (TAILQ_FIRST(&head->queue) == head->switch_point) 175 head->switch_point = NULL; 176 } 177 178 static __inline struct bio * 179 bioq_first(struct bio_queue_head *head) 180 { 181 return (TAILQ_FIRST(&head->queue)); 182 } 183 184 #endif /* _KERNEL */ 185 186 #endif /* !_SYS_BUF2_H_ */ 187