sys/sys/bio.h

   1 /*
   2  * Copyright (c) 2004, 2005 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Hiten Pandya <hmp@backplane.com>.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sys/sys/bio.h,v 1.5 2006/05/20 02:42:13 dillon Exp $
  35  */
  36
  37 #ifndef _SYS_BIO_H_
  38 #define _SYS_BIO_H_
  39
  40 #ifndef _SYS_TYPES_H_
  41 #include <sys/types.h>
  42 #endif
  43 #ifndef _SYS_QUEUE_H_
  44 #include <sys/queue.h>
  45 #endif
  46
  47 struct bio;
  48 struct bio_track;
  49
  50 typedef void biodone_t(struct bio *);
  51
  52 /*
  53  * BIO encapsulation for storage drivers and systems that do not require
  54  * caching support for underlying blocks.
  55  *
  56  * NOTE: bio_done and bio_caller_info belong to the caller, while
  57  * bio_driver_info belongs to the driver.
  58  *
  59  * bio_track is only non-NULL when an I/O is in progress.
  60  */
  61 struct bio {
  62         TAILQ_ENTRY(bio) bio_act;       /* driver queue when active */
  63         struct bio_track *bio_track;    /* BIO tracking structure */
  64         struct bio      *bio_prev;      /* BIO stack */
  65         struct bio      *bio_next;      /* BIO stack / cached translations */
  66         struct buf      *bio_buf;       /* High-level buffer back-pointer. */
  67         biodone_t       *bio_done;      /* Caller completion function */
  68         off_t           bio_offset;     /* Logical offset relative to device */
  69         void            *bio_driver_info;
  70         union {
  71                 void    *ptr;
  72                 off_t   offset;
  73                 int     index;
  74                 struct buf *cluster_head;
  75                 struct bio *cluster_parent;
  76         } bio_caller_info1;
  77         union {
  78                 void    *ptr;
  79                 off_t   offset;
  80                 int     index;
  81                 struct buf *cluster_tail;
  82         } bio_caller_info2;
  83 };
  84
  85 void bio_start_transaction(struct bio *, struct bio_track *);
  86
  87 #endif