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Annotation of kernel/bsd/sys/buf.h, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
        !             3:  *
        !             4:  * @APPLE_LICENSE_HEADER_START@
        !             5:  * 
        !             6:  * Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
        !             7:  * Reserved.  This file contains Original Code and/or Modifications of
        !             8:  * Original Code as defined in and that are subject to the Apple Public
        !             9:  * Source License Version 1.1 (the "License").  You may not use this file
        !            10:  * except in compliance with the License.  Please obtain a copy of the
        !            11:  * License at http://www.apple.com/publicsource and read it before using
        !            12:  * this file.
        !            13:  * 
        !            14:  * The Original Code and all software distributed under the License are
        !            15:  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
        !            16:  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
        !            17:  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
        !            18:  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
        !            19:  * License for the specific language governing rights and limitations
        !            20:  * under the License.
        !            21:  * 
        !            22:  * @APPLE_LICENSE_HEADER_END@
        !            23:  */
        !            24: 
        !            25: /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
        !            26: /*
        !            27:  * Copyright (c) 1982, 1986, 1989, 1993
        !            28:  *     The Regents of the University of California.  All rights reserved.
        !            29:  * (c) UNIX System Laboratories, Inc.
        !            30:  * All or some portions of this file are derived from material licensed
        !            31:  * to the University of California by American Telephone and Telegraph
        !            32:  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
        !            33:  * the permission of UNIX System Laboratories, Inc.
        !            34:  *
        !            35:  * Redistribution and use in source and binary forms, with or without
        !            36:  * modification, are permitted provided that the following conditions
        !            37:  * are met:
        !            38:  * 1. Redistributions of source code must retain the above copyright
        !            39:  *    notice, this list of conditions and the following disclaimer.
        !            40:  * 2. Redistributions in binary form must reproduce the above copyright
        !            41:  *    notice, this list of conditions and the following disclaimer in the
        !            42:  *    documentation and/or other materials provided with the distribution.
        !            43:  * 3. All advertising materials mentioning features or use of this software
        !            44:  *    must display the following acknowledgement:
        !            45:  *     This product includes software developed by the University of
        !            46:  *     California, Berkeley and its contributors.
        !            47:  * 4. Neither the name of the University nor the names of its contributors
        !            48:  *    may be used to endorse or promote products derived from this software
        !            49:  *    without specific prior written permission.
        !            50:  *
        !            51:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            52:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            53:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            54:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            55:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            56:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            57:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            58:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            59:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            60:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            61:  * SUCH DAMAGE.
        !            62:  *
        !            63:  *     @(#)buf.h       8.9 (Berkeley) 3/30/95
        !            64:  */
        !            65: 
        !            66: #ifndef _SYS_BUF_H_
        !            67: #define        _SYS_BUF_H_
        !            68: #include <sys/queue.h>
        !            69: #include <sys/errno.h>
        !            70: 
        !            71: #include <sys/vm.h>
        !            72: 
        !            73: #define NOLIST ((struct buf *)0x87654321)
        !            74: 
        !            75: #include <sys/cdefs.h>
        !            76: 
        !            77: /*
        !            78:  * The buffer header describes an I/O operation in the kernel.
        !            79:  */
        !            80: struct buf {
        !            81:        LIST_ENTRY(buf) b_hash;         /* Hash chain. */
        !            82:        LIST_ENTRY(buf) b_vnbufs;       /* Buffer's associated vnode. */
        !            83:        TAILQ_ENTRY(buf) b_freelist;    /* Free list position if not active. */
        !            84:        struct  buf *b_actf, **b_actb;  /* Device driver queue when active. */
        !            85:        struct  proc *b_proc;           /* Associated proc; NULL if kernel. */
        !            86:        volatile long   b_flags;        /* B_* flags. */
        !            87:        int     b_error;                /* Errno value. */
        !            88:        long    b_bufsize;              /* Allocated buffer size. */
        !            89:        long    b_bcount;               /* Valid bytes in buffer. */
        !            90:        long    b_resid;                /* Remaining I/O. */
        !            91:        dev_t   b_dev;                  /* Device associated with buffer. */
        !            92:        struct {
        !            93:                caddr_t b_addr;         /* Memory, superblocks, indirect etc.*/
        !            94:        } b_un;
        !            95:        void    *b_saveaddr;            /* Original b_addr for physio. */
        !            96:        daddr_t b_lblkno;               /* Logical block number. */
        !            97:        daddr_t b_blkno;                /* Underlying physical block number. */
        !            98:                                        /* Function to call upon completion. */
        !            99:        void    (*b_iodone) __P((struct buf *));
        !           100:        struct  vnode *b_vp;            /* Device vnode. */
        !           101:        int     b_dirtyoff;             /* Offset in buffer of dirty region. */
        !           102:        int     b_dirtyend;             /* Offset of end of dirty region. */
        !           103:        struct  ucred *b_rcred;         /* Read credentials reference. */
        !           104:        struct  ucred *b_wcred;         /* Write credentials reference. */
        !           105:        int     b_validoff;             /* Offset in buffer of valid region. */
        !           106:        int     b_validend;             /* Offset of end of valid region. */
        !           107:        void    *b_drvdata;             /* driver specific data */
        !           108:        long    b_reserved[4];  /* Reserved for future HFS use */
        !           109: };
        !           110: 
        !           111: /*
        !           112:  * For portability with historic industry practice, the cylinder number has
        !           113:  * to be maintained in the `b_resid' field.
        !           114:  */
        !           115: #define        b_cylinder b_resid              /* Cylinder number for disksort(). */
        !           116: 
        !           117: /* Device driver compatibility definitions. */
        !           118: #define        b_active b_bcount               /* Driver queue head: drive active. */
        !           119: #define        b_data   b_un.b_addr            /* b_un.b_addr is not changeable. */
        !           120: #define        b_errcnt b_resid                /* Retry count while I/O in progress. */
        !           121: #define        iodone   biodone                /* Old name for biodone. */
        !           122: #define        iowait   biowait                /* Old name for biowait. */
        !           123: 
        !           124: /*
        !           125:  * These flags are kept in b_flags.
        !           126:  */
        !           127: #define        B_AGE           0x00000001      /* Move to age queue when I/O done. */
        !           128: #define        B_NEEDCOMMIT    0x00000002      /* Append-write in progress. */
        !           129: #define        B_ASYNC         0x00000004      /* Start I/O, do not wait. */
        !           130: #define        B_BAD           0x00000008      /* Bad block revectoring in progress. */
        !           131: #define        B_BUSY          0x00000010      /* I/O in progress. */
        !           132: #define        B_CACHE         0x00000020      /* Bread found us in the cache. */
        !           133: #define        B_CALL          0x00000040      /* Call b_iodone from biodone. */
        !           134: #define        B_DELWRI        0x00000080      /* Delay I/O until buffer reused. */
        !           135: #define        B_DIRTY         0x00000100      /* Dirty page to be pushed out async. */
        !           136: #define        B_DONE          0x00000200      /* I/O completed. */
        !           137: #define        B_EINTR         0x00000400      /* I/O was interrupted */
        !           138: #define        B_ERROR         0x00000800      /* I/O error occurred. */
        !           139: #define        B_GATHERED      0x00001000      /* LFS: already in a segment. */
        !           140: #define        B_INVAL         0x00002000      /* Does not contain valid info. */
        !           141: #define        B_LOCKED        0x00004000      /* Locked in core (not reusable). */
        !           142: #define        B_NOCACHE       0x00008000      /* Do not cache block after use. */
        !           143: #define        B_PAGET         0x00010000      /* Page in/out of page table space. */
        !           144: #define        B_PGIN          0x00020000      /* Pagein op, so swap() can count it. */
        !           145: #define        B_PHYS          0x00040000      /* I/O to user memory. */
        !           146: #define        B_RAW           0x00080000      /* Set by physio for raw transfers. */
        !           147: #define        B_READ          0x00100000      /* Read buffer. */
        !           148: #define        B_TAPE          0x00200000      /* Magnetic tape I/O. */
        !           149: #define        B_UAREA         0x00400000      /* Buffer describes Uarea I/O. */
        !           150: #define        B_WANTED        0x00800000      /* Process wants this buffer. */
        !           151: #define        B_WRITE         0x00000000      /* Write buffer (pseudo flag). */
        !           152: #define        B_WRITEINPROG   0x01000000      /* Write in progress. */
        !           153: #define        B_XXX           0x02000000      /* Debugging flag. */
        !           154: #define B_KERNSPACE    0x04000000      /* physical I/O to kernel space */
        !           155: #define B_CLUST_SYNC    0x08000000      /* part of synchronous cluster write */
        !           156: #define B_CLUST_COMMIT  0x10000000      /* commit cluster to disk and wait */
        !           157: 
        !           158: #define        B_SCRACH5       0x40000000      /* Used by device drivers. */
        !           159: #define        B_SCRACH6       0x80000000      /* Used by device drivers. */
        !           160: 
        !           161: /*
        !           162:  * This structure describes a clustered I/O.  It is stored in the b_saveaddr
        !           163:  * field of the buffer on which I/O is done.  At I/O completion, cluster
        !           164:  * callback uses the structure to parcel I/O's to individual buffers, and
        !           165:  * then free's this structure.
        !           166:  */
        !           167: struct cluster_save {
        !           168:        long    bs_bcount;              /* Saved b_bcount. */
        !           169:        long    bs_bufsize;             /* Saved b_bufsize. */
        !           170:        void    *bs_saveaddr;           /* Saved b_addr. */
        !           171:        int     bs_nchildren;           /* Number of associated buffers. */
        !           172:        struct buf **bs_children;       /* List of associated buffers. */
        !           173: };
        !           174: 
        !           175: /*
        !           176:  * Zero out the buffer's data area.
        !           177:  */
        !           178: #define        clrbuf(bp) {                                                    \
        !           179:        bzero((bp)->b_data, (u_int)(bp)->b_bcount);                     \
        !           180:        (bp)->b_resid = 0;                                              \
        !           181: }
        !           182: 
        !           183: /* Flags to low-level allocation routines. */
        !           184: #define B_CLRBUF       0x01    /* Request allocated buffer be cleared. */
        !           185: #define B_SYNC         0x02    /* Do all allocations synchronously. */
        !           186: 
        !           187: #ifdef _KERNEL
        !           188: extern int nbuf;                       /* The number of buffer headers */
        !           189: extern struct buf *buf;                /* The buffer headers. */
        !           190: extern char    *buffers;               /* The buffer contents. */
        !           191: extern int bufpages;           /* Number of memory pages in the buffer pool. */
        !           192: extern struct buf *swbuf;      /* Swap I/O buffer headers. */
        !           193: extern int nswbuf;                     /* Number of swap I/O buffer headers. */
        !           194: extern struct buf bswlist;     /* Head of swap I/O buffer headers free list. */
        !           195: extern struct buf *bclnlist;/* Head of cleaned page list. */
        !           196: 
        !           197: __BEGIN_DECLS
        !           198: int    allocbuf __P((struct buf *, int));
        !           199: void   bawrite __P((struct buf *));
        !           200: void   bdwrite __P((struct buf *));
        !           201: void   biodone __P((struct buf *));
        !           202: int    biowait __P((struct buf *));
        !           203: int    bread __P((struct vnode *, daddr_t, int,
        !           204:            struct ucred *, struct buf **));
        !           205: int    breada __P((struct vnode *, daddr_t, int, daddr_t, int,
        !           206:            struct ucred *, struct buf **));
        !           207: int    breadn __P((struct vnode *, daddr_t, int, daddr_t *, int *, int,
        !           208:            struct ucred *, struct buf **));
        !           209: void   brelse __P((struct buf *));
        !           210: void   bremfree __P((struct buf *));
        !           211: void   bufinit __P((void));
        !           212: int    bwrite __P((struct buf *));
        !           213: void   cluster_callback __P((struct buf *));
        !           214: int    cluster_read __P((struct vnode *, u_quad_t, daddr_t, long,
        !           215:            struct ucred *, struct buf **, long, int, long, int *));
        !           216: int     advisory_read __P((struct vnode *, u_quad_t, daddr_t, long,
        !           217:            long, long, long));
        !           218: int    cluster_write __P((struct buf *, u_quad_t, long));
        !           219: struct buf *getblk __P((struct vnode *, daddr_t, int, int, int));
        !           220: struct buf *geteblk __P((int));
        !           221: struct buf *getnewbuf __P((int slpflag, int slptimeo));
        !           222: struct buf *incore __P((struct vnode *, daddr_t));
        !           223: u_int  minphys __P((struct buf *bp));
        !           224: __END_DECLS
        !           225: #endif
        !           226: #endif /* !_SYS_BUF_H_ */

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