FreeBSD/Linux Kernel Cross Reference
sys/bsd/sys/buf.h

     /*
      * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
      *
      * @APPLE_LICENSE_HEADER_START@
      * 
      * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
      * 
      * This file contains Original Code and/or Modifications of Original Code
      * as defined in and that are subject to the Apple Public Source License
     * Version 2.0 (the 'License'). You may not use this file except in
     * compliance with the License. Please obtain a copy of the License at
     * http://www.opensource.apple.com/apsl/ and read it before using this
     * file.
     * 
     * The Original Code and all software distributed under the License are
     * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
     * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
     * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
     * Please see the License for the specific language governing rights and
     * limitations under the License.
     * 
     * @APPLE_LICENSE_HEADER_END@
     */
    /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
    /*
     * Copyright (c) 1982, 1986, 1989, 1993
     *      The Regents of the University of California.  All rights reserved.
     * (c) UNIX System Laboratories, Inc.
     * All or some portions of this file are derived from material licensed
     * to the University of California by American Telephone and Telegraph
     * Co. or Unix System Laboratories, Inc. and are reproduced herein with
     * the permission of UNIX System Laboratories, Inc.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      @(#)buf.h       8.9 (Berkeley) 3/30/95
     */
    
    #ifndef _SYS_BUF_H_
    #define _SYS_BUF_H_
    
    #include <sys/appleapiopts.h>
    
    #ifdef KERNEL
    #include <sys/queue.h>
    #include <sys/errno.h>
    #include <sys/vm.h>
    #include <sys/cdefs.h>
    
    #ifdef __APPLE_API_PRIVATE
    
    #define NOLIST ((struct buf *)0x87654321)
    
    /*
     * The buffer header describes an I/O operation in the kernel.
     */
    struct buf {
            LIST_ENTRY(buf) b_hash;         /* Hash chain. */
            LIST_ENTRY(buf) b_vnbufs;       /* Buffer's associated vnode. */
            TAILQ_ENTRY(buf) b_freelist;    /* Free list position if not active. */
            struct  proc *b_proc;           /* Associated proc; NULL if kernel. */
            volatile long   b_flags;        /* B_* flags. */
            int     b_error;                /* Errno value. */
            long    b_bufsize;              /* Allocated buffer size. */
            long    b_bcount;               /* Valid bytes in buffer. */
            long    b_resid;                /* Remaining I/O. */
            dev_t   b_dev;                  /* Device associated with buffer. */
            struct {
                    caddr_t b_addr;         /* Memory, superblocks, indirect etc.*/
            } b_un;
            void    *b_saveaddr;            /* Original b_addr for physio. */
            daddr_t b_lblkno;               /* Logical block number. */
           daddr_t b_blkno;                /* Underlying physical block number. */
                                           /* Function to call upon completion. */
           void    (*b_iodone) __P((struct buf *));
           struct  vnode *b_vp;            /* Device vnode. */
           int     b_dirtyoff;             /* Offset in buffer of dirty region. */
           int     b_dirtyend;             /* Offset of end of dirty region. */
           int     b_validoff;             /* Offset in buffer of valid region. */
           int     b_validend;             /* Offset of end of valid region. */
           struct  ucred *b_rcred;         /* Read credentials reference. */
           struct  ucred *b_wcred;         /* Write credentials reference. */
           int     b_timestamp;            /* timestamp for queuing operation */
           long    b_vectorcount;  /* number of vectors in b_vectorlist */
           void    *b_vectorlist;  /* vector list for I/O */
           void    *b_pagelist;    /* to save pagelist info */
           long    b_vects[2];             /* vectorlist when b_vectorcount is 1 */
           long    b_whichq;               /* the free list the buffer belongs to */
           TAILQ_ENTRY(buf)        b_act;  /* Device driver queue when active */
           void    *b_drvdata;             /* Device driver private use */
   };
   
   /*
    * For portability with historic industry practice, the cylinder number has
    * to be maintained in the `b_resid' field.
    */
   #define b_cylinder b_resid              /* Cylinder number for disksort(). */
   
   /* Device driver compatibility definitions. */
   #define b_active b_bcount               /* Driver queue head: drive active. */
   #define b_data   b_un.b_addr            /* b_un.b_addr is not changeable. */
   #define b_errcnt b_resid                /* Retry count while I/O in progress. */
   #define iodone   biodone                /* Old name for biodone. */
   #define iowait   biowait                /* Old name for biowait. */
   
   /* cluster_io definitions for use with io bufs */
   #define b_uploffset  b_bufsize
   #define b_trans_head b_freelist.tqe_prev
   #define b_trans_next b_freelist.tqe_next
   #define b_real_bp    b_saveaddr
   #define b_iostate    b_rcred
   
   /* journaling uses this cluster i/o field for its own
    * purposes because meta data buf's should never go
    * through the clustering code.
    */
   #define b_transaction b_vectorlist
   
      
   
   /*
    * These flags are kept in b_flags.
    */
   #define B_AGE           0x00000001      /* Move to age queue when I/O done. */
   #define B_NEEDCOMMIT    0x00000002      /* Append-write in progress. */
   #define B_ASYNC         0x00000004      /* Start I/O, do not wait. */
   #define B_BAD           0x00000008      /* Bad block revectoring in progress. */
   #define B_BUSY          0x00000010      /* I/O in progress. */
   #define B_CACHE         0x00000020      /* Bread found us in the cache. */
   #define B_CALL          0x00000040      /* Call b_iodone from biodone. */
   #define B_DELWRI        0x00000080      /* Delay I/O until buffer reused. */
   #define B_DIRTY         0x00000100      /* Dirty page to be pushed out async. */
   #define B_DONE          0x00000200      /* I/O completed. */
   #define B_EINTR         0x00000400      /* I/O was interrupted */
   #define B_ERROR         0x00000800      /* I/O error occurred. */
   #define B_WASDIRTY      0x00001000      /* page was found dirty in the VM cache */
   #define B_INVAL         0x00002000      /* Does not contain valid info. */
   #define B_LOCKED        0x00004000      /* Locked in core (not reusable). */
   #define B_NOCACHE       0x00008000      /* Do not cache block after use. */
   #define B_PAGEOUT       0x00010000      /* Page out indicator... */
   #define B_PGIN          0x00020000      /* Pagein op, so swap() can count it. */
   #define B_PHYS          0x00040000      /* I/O to user memory. */
   #define B_RAW           0x00080000      /* Set by physio for raw transfers. */
   #define B_READ          0x00100000      /* Read buffer. */
   #define B_TAPE          0x00200000      /* Magnetic tape I/O. */
   #define B_PAGELIST      0x00400000      /* Buffer describes pagelist I/O. */
   #define B_WANTED        0x00800000      /* Process wants this buffer. */
   #define B_WRITE         0x00000000      /* Write buffer (pseudo flag). */
   #define B_WRITEINPROG   0x01000000      /* Write in progress. */
   #define B_HDRALLOC      0x02000000      /* zone allocated buffer header */
   #define B_NORELSE       0x04000000      /* don't brelse() in bwrite() */
   #define B_NEED_IODONE   0x08000000
                                                                   /* need to do a biodone on the */
                                                                   /* real_bp associated with a cluster_io */
   #define B_COMMIT_UPL    0x10000000
                                                                   /* commit pages in upl when */
                                                                   /* I/O completes/fails */
   #define B_ZALLOC        0x20000000      /* b_data is zalloc()ed */
   #define B_META          0x40000000      /* buffer contains meta-data. */
   #define B_VECTORLIST    0x80000000      /* Used by device drivers. */
   
   
   /*
    * Zero out the buffer's data area.
    */
   #define clrbuf(bp) {                                                    \
           bzero((bp)->b_data, (u_int)(bp)->b_bcount);                     \
           (bp)->b_resid = 0;                                              \
   }
   
   /* Flags to low-level allocation routines. */
   #define B_CLRBUF        0x01    /* Request allocated buffer be cleared. */
   #define B_SYNC          0x02    /* Do all allocations synchronously. */
   #define B_NOBUFF        0x04    /* Do not allocate struct buf */
   
   /* Flags for operation type in getblk() */
   #define BLK_READ        0x01    /* buffer for read */
   #define BLK_WRITE       0x02    /* buffer for write */
   #define BLK_PAGEIN      0x04    /* buffer for pagein */
   #define BLK_PAGEOUT     0x08    /* buffer for pageout */
   #define BLK_META        0x10    /* buffer for metadata */
   #define BLK_CLREAD      0x20    /* buffer for cluster read */
   #define BLK_CLWRITE     0x40    /* buffer for cluster write */
   
   extern int nbuf;                        /* The number of buffer headers */
   extern struct buf *buf;         /* The buffer headers. */
   
   #endif /* __APPLE_API_PRIVATE */
   
   
   #ifdef __APPLE_API_UNSTABLE
   /* Macros to clear/set/test flags. */
   #define SET(t, f)       (t) |= (f)
   #define CLR(t, f)       (t) &= ~(f)
   #define ISSET(t, f)     ((t) & (f))
   #endif /* __APPLE_API_UNSTABLE */
   
   #ifdef __APPLE_API_PRIVATE
   /*
    * Definitions for the buffer free lists.
    */
   #define BQUEUES         6               /* number of free buffer queues */
   
   #define BQ_LOCKED       0               /* super-blocks &c */
   #define BQ_LRU          1               /* lru, useful buffers */
   #define BQ_AGE          2               /* rubbish */
   #define BQ_EMPTY        3               /* buffer headers with no memory */
   #define BQ_META         4               /* buffer containing metadata */
   #define BQ_LAUNDRY      5               /* buffers that need cleaning */
   #endif /* __APPLE_API_PRIVATE */
   
   __BEGIN_DECLS
   #ifdef __APPLE_API_UNSTABLE
   int     allocbuf __P((struct buf *, int));
   void    bawrite __P((struct buf *));
   void    bdwrite __P((struct buf *));
   void    biodone __P((struct buf *));
   int     biowait __P((struct buf *));
   int     bread __P((struct vnode *, daddr_t, int,
               struct ucred *, struct buf **));
   int     meta_bread __P((struct vnode *, daddr_t, int,
               struct ucred *, struct buf **));
   int     breada __P((struct vnode *, daddr_t, int, daddr_t, int,
               struct ucred *, struct buf **));
   int     breadn __P((struct vnode *, daddr_t, int, daddr_t *, int *, int,
               struct ucred *, struct buf **));
   int     meta_breadn __P((struct vnode *, daddr_t, int, daddr_t *, int *, int,
               struct ucred *, struct buf **));
   void    brelse __P((struct buf *));
   void    bremfree __P((struct buf *));
   void    bufinit __P((void));
   void    bwillwrite __P((void));
   int     bwrite __P((struct buf *));
   struct buf *getblk __P((struct vnode *, daddr_t, int, int, int, int));
   struct buf *geteblk __P((int));
   struct buf *incore __P((struct vnode *, daddr_t));
   u_int   minphys __P((struct buf *bp));
   int physio __P((void (*)(struct buf *), struct buf *, dev_t, int ,  u_int (*)(struct buf *), struct uio *, int ));
   int count_busy_buffers __P((void));
   struct buf *alloc_io_buf __P((struct vnode *, int));
   void free_io_buf __P((struct buf *));
   void reassignbuf __P((struct buf *, struct vnode *));
   #endif /* __APPLE_API_UNSTABLE */
   __END_DECLS
   
   #ifdef __APPLE_API_PRIVATE
   /*
    *      Stats on usefulness of the buffer cache
    */
   struct bufstats {
           long    bufs_incore;            /* found incore */
           long    bufs_busyincore;        /* found incore. was busy */
           long    bufs_vmhits;            /* not incore. found in VM */
           long    bufs_miss;                      /* not incore. not in VM */
           long    bufs_sleeps;            /* buffer starvation */
           long    bufs_eblk;                      /* Calls to geteblk */
           long    bufs_iobufmax;          /* Max. number of IO buffers used */
           long    bufs_iobufinuse;        /* number of IO buffers in use */
           long    bufs_iobufsleeps;       /* IO buffer starvation */
   };
   #endif /* __APPLE_API_PRIVATE */
   
   #endif /* KERNEL */
   #endif /* !_SYS_BUF_H_ */

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