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 1.21 2008/01/28 07:19:06 nth Exp $ 41 */ 42 43 #ifndef _SYS_BUF2_H_ 44 #define _SYS_BUF2_H_ 45 46 #ifdef _KERNEL 47 48 #ifndef _SYS_BUF_H_ 49 #include <sys/buf.h> /* crit_*() functions */ 50 #endif 51 #ifndef _SYS_GLOBALDATA_H_ 52 #include <sys/globaldata.h> /* curthread */ 53 #endif 54 #ifndef _SYS_THREAD2_H_ 55 #include <sys/thread2.h> /* crit_*() functions */ 56 #endif 57 #ifndef _SYS_SPINLOCK2_H_ 58 #include <sys/spinlock2.h> /* crit_*() functions */ 59 #endif 60 #ifndef _SYS_MOUNT_H_ 61 #include <sys/mount.h> 62 #endif 63 #ifndef _SYS_VNODE_H_ 64 #include <sys/vnode.h> 65 #endif 66 #ifndef _VM_VM_PAGE_H_ 67 #include <vm/vm_page.h> 68 #endif 69 70 /* 71 * Initialize a lock. 72 */ 73 #define BUF_LOCKINIT(bp) \ 74 lockinit(&(bp)->b_lock, buf_wmesg, 0, 0) 75 76 /* 77 * 78 * Get a lock sleeping non-interruptably until it becomes available. 79 * 80 * XXX lk_wmesg can race, but should not result in any operational issues. 81 */ 82 static __inline int 83 BUF_LOCK(struct buf *bp, int locktype) 84 { 85 bp->b_lock.lk_wmesg = buf_wmesg; 86 return (lockmgr(&(bp)->b_lock, locktype)); 87 } 88 /* 89 * Get a lock sleeping with specified interruptably and timeout. 90 * 91 * XXX lk_timo can race against other entities calling BUF_TIMELOCK, 92 * but will not interfere with entities calling BUF_LOCK since LK_TIMELOCK 93 * will not be set in that case. 94 * 95 * XXX lk_wmesg can race, but should not result in any operational issues. 96 */ 97 static __inline int 98 BUF_TIMELOCK(struct buf *bp, int locktype, char *wmesg, int timo) 99 { 100 bp->b_lock.lk_wmesg = wmesg; 101 bp->b_lock.lk_timo = timo; 102 return (lockmgr(&(bp)->b_lock, locktype | LK_TIMELOCK)); 103 } 104 /* 105 * Release a lock. Only the acquiring process may free the lock unless 106 * it has been handed off to biodone. 107 */ 108 static __inline void 109 BUF_UNLOCK(struct buf *bp) 110 { 111 lockmgr(&(bp)->b_lock, LK_RELEASE); 112 } 113 114 /* 115 * When initiating asynchronous I/O, change ownership of the lock to the 116 * kernel. Once done, the lock may legally released by biodone. The 117 * original owning process can no longer acquire it recursively, but must 118 * wait until the I/O is completed and the lock has been freed by biodone. 119 */ 120 static __inline void 121 BUF_KERNPROC(struct buf *bp) 122 { 123 lockmgr_kernproc(&(bp)->b_lock); 124 } 125 /* 126 * Find out the number of references to a lock. 127 * 128 * The non-blocking version should only be used for assertions in cases 129 * where the buffer is expected to be owned or otherwise data stable. 130 */ 131 static __inline int 132 BUF_REFCNT(struct buf *bp) 133 { 134 return (lockcount(&(bp)->b_lock)); 135 } 136 137 static __inline int 138 BUF_REFCNTNB(struct buf *bp) 139 { 140 return (lockcountnb(&(bp)->b_lock)); 141 } 142 143 /* 144 * Free a buffer lock. 145 */ 146 #define BUF_LOCKFREE(bp) \ 147 if (BUF_REFCNTNB(bp) > 0) \ 148 panic("free locked buf") 149 150 static __inline void 151 bioq_init(struct bio_queue_head *bioq) 152 { 153 TAILQ_INIT(&bioq->queue); 154 bioq->off_unused = 0; 155 bioq->reorder = 0; 156 bioq->transition = NULL; 157 bioq->bio_unused = NULL; 158 } 159 160 static __inline void 161 bioq_insert_tail(struct bio_queue_head *bioq, struct bio *bio) 162 { 163 bioq->transition = NULL; 164 TAILQ_INSERT_TAIL(&bioq->queue, bio, bio_act); 165 } 166 167 static __inline void 168 bioq_remove(struct bio_queue_head *bioq, struct bio *bio) 169 { 170 /* 171 * Adjust read insertion point when removing the bioq. The 172 * bio after the insert point is a write so move backwards 173 * one (NULL will indicate all the reads have cleared). 174 */ 175 if (bio == bioq->transition) 176 bioq->transition = TAILQ_NEXT(bio, bio_act); 177 TAILQ_REMOVE(&bioq->queue, bio, bio_act); 178 } 179 180 static __inline struct bio * 181 bioq_first(struct bio_queue_head *bioq) 182 { 183 return (TAILQ_FIRST(&bioq->queue)); 184 } 185 186 /* 187 * Adjust buffer cache buffer's activity count. This 188 * works similarly to vm_page->act_count. 189 */ 190 static __inline void 191 buf_act_advance(struct buf *bp) 192 { 193 if (bp->b_act_count > ACT_MAX - ACT_ADVANCE) 194 bp->b_act_count = ACT_MAX; 195 else 196 bp->b_act_count += ACT_ADVANCE; 197 } 198 199 static __inline void 200 buf_act_decline(struct buf *bp) 201 { 202 if (bp->b_act_count < ACT_DECLINE) 203 bp->b_act_count = 0; 204 else 205 bp->b_act_count -= ACT_DECLINE; 206 } 207 208 /* 209 * biodeps inlines - used by softupdates and HAMMER. 210 */ 211 static __inline void 212 buf_dep_init(struct buf *bp) 213 { 214 bp->b_ops = NULL; 215 LIST_INIT(&bp->b_dep); 216 } 217 218 /* 219 * Precondition: the buffer has some dependencies. 220 */ 221 static __inline void 222 buf_deallocate(struct buf *bp) 223 { 224 struct bio_ops *ops = bp->b_ops; 225 226 KKASSERT(! LIST_EMPTY(&bp->b_dep)); 227 if (ops) 228 ops->io_deallocate(bp); 229 } 230 231 static __inline int 232 buf_countdeps(struct buf *bp, int n) 233 { 234 struct bio_ops *ops = bp->b_ops; 235 int r; 236 237 if (ops) 238 r = ops->io_countdeps(bp, n); 239 else 240 r = 0; 241 return(r); 242 } 243 244 static __inline void 245 buf_start(struct buf *bp) 246 { 247 struct bio_ops *ops = bp->b_ops; 248 249 if (ops) 250 ops->io_start(bp); 251 } 252 253 static __inline void 254 buf_complete(struct buf *bp) 255 { 256 struct bio_ops *ops = bp->b_ops; 257 258 if (ops) 259 ops->io_complete(bp); 260 } 261 262 static __inline int 263 buf_fsync(struct vnode *vp) 264 { 265 struct bio_ops *ops = vp->v_mount->mnt_bioops; 266 int r; 267 268 if (ops) 269 r = ops->io_fsync(vp); 270 else 271 r = 0; 272 return(r); 273 } 274 275 static __inline void 276 buf_movedeps(struct buf *bp1, struct buf *bp2) 277 { 278 struct bio_ops *ops = bp1->b_ops; 279 280 if (ops) 281 ops->io_movedeps(bp1, bp2); 282 } 283 284 static __inline int 285 buf_checkread(struct buf *bp) 286 { 287 struct bio_ops *ops = bp->b_ops; 288 289 if (ops) 290 return(ops->io_checkread(bp)); 291 return(0); 292 } 293 294 static __inline int 295 buf_checkwrite(struct buf *bp) 296 { 297 struct bio_ops *ops = bp->b_ops; 298 299 if (ops) 300 return(ops->io_checkwrite(bp)); 301 return(0); 302 } 303 304 /* 305 * Chained biodone. The bio callback was made and the callback function 306 * wishes to chain the biodone. If no BIO's are left we call bpdone() 307 * with elseit=TRUE (asynchronous completion). 308 */ 309 static __inline void 310 biodone_chain(struct bio *bio) 311 { 312 if (bio->bio_prev) 313 biodone(bio->bio_prev); 314 else 315 bpdone(bio->bio_buf, 1); 316 } 317 318 #endif /* _KERNEL */ 319 320 #endif /* !_SYS_BUF2_H_ */ 321