FreeBSD/Linux Kernel Cross Reference
sys/sys/bufq.h

     /*      $NetBSD: bufq.h,v 1.2.10.1 2005/04/06 11:56:25 tron Exp $       */
     /*      NetBSD: buf.h,v 1.75 2004/09/18 16:40:11 yamt Exp       */
     
     /*-
      * Copyright (c) 1999, 2000 The NetBSD Foundation, Inc.
      * All rights reserved.
      *
      * This code is derived from software contributed to The NetBSD Foundation
      * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
     * NASA Ames Research Center.
     *
     * 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 NetBSD
     *      Foundation, Inc. and its contributors.
     * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
     */
    
    /*
     * 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. 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
     */
    
    #if !defined(_KERNEL)
    #error not supposed to be exposed to userland.
    #endif
    
    struct buf;
    
    /*
     * Device driver buffer queue.
     */
    struct bufq_state {
            void (*bq_put)(struct bufq_state *, struct buf *);
            struct buf *(*bq_get)(struct bufq_state *, int);
            void *bq_private;
            int bq_flags;                   /* Flags from bufq_alloc() */
    };
    
    /*
     * Flags for bufq_alloc.
     */
    #define BUFQ_SORT_RAWBLOCK      0x0001  /* Sort by b_rawblkno */
    #define BUFQ_SORT_CYLINDER      0x0002  /* Sort by b_cylinder, b_rawblkno */
    
    #define _BUFQ_DEFAULT           0x00f0  /* Let bufq_alloc() choose strategy */
   #define BUFQ_FCFS               0x0010  /* First-come first-serve */
   #define BUFQ_DISKSORT           0x0020  /* Min seek sort */
   #define BUFQ_READ_PRIO          0x0030  /* Min seek and read priority */
   #define BUFQ_PRIOCSCAN          0x0040  /* Per-priority CSCAN */
   
   #define BUFQ_SORT_MASK          0x000f
   #define BUFQ_METHOD_MASK        0x00f0
   
   extern int bufq_disk_default_strat;
   #define BUFQ_DISK_DEFAULT_STRAT()       bufq_disk_default_strat
   void    bufq_alloc(struct bufq_state *, int);
   void    bufq_drain(struct bufq_state *);
   void    bufq_free(struct bufq_state *);
   
   #define BUFQ_PUT(bufq, bp) \
           (*(bufq)->bq_put)((bufq), (bp)) /* Put buffer in queue */
   #define BUFQ_GET(bufq) \
           (*(bufq)->bq_get)((bufq), 1)    /* Get and remove buffer from queue */
   #define BUFQ_PEEK(bufq) \
           (*(bufq)->bq_get)((bufq), 0)    /* Get buffer from queue */
   
   static __inline int buf_inorder(const struct buf *, const struct buf *, int)
       __unused;
   
   #include <sys/null.h> /* for NULL */
   
   /*
    * Check if two buf's are in ascending order.
    */
   static __inline int
   buf_inorder(const struct buf *bp, const struct buf *bq, int sortby)
   {
   
           if (bp == NULL || bq == NULL)
                   return (bq == NULL);
   
           if (sortby == BUFQ_SORT_CYLINDER) {
                   if (bp->b_cylinder != bq->b_cylinder)
                           return bp->b_cylinder < bq->b_cylinder;
                   else
                           return bp->b_rawblkno < bq->b_rawblkno;
           } else
                   return bp->b_rawblkno < bq->b_rawblkno;
   }
   
   struct bufq_strat {
           const char *bs_name;
           void (*bs_initfn)(struct bufq_state *);
           int bs_id;
   };
   
   #define BUFQ_DEFINE(name, id, initfn)                   \
   static const struct bufq_strat bufq_strat_##name = {    \
           .bs_name = #name,                               \
           .bs_id = id,                                    \
           .bs_initfn = initfn                             \
   };                                                      \
   __link_set_add_rodata(bufq_strats, bufq_strat_##name)
   

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