sys/vfs/devfs/devfs_helper.c

   1 /*
   2  * Copyright (c) 2009 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Alex Hornung <ahornung@gmail.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 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/kernel.h>
  37 #include <sys/types.h>
  38 #include <sys/param.h>
  39 #include <machine/limits.h>
  40 #include <sys/devfs.h>
  41
  42 MALLOC_DECLARE(M_DEVFS);
  43
  44 /*
  45  * DEVFS clone bitmap functions
  46  */
  47 void
  48 devfs_clone_bitmap_init(struct devfs_bitmap *bitmap)
  49 {
  50         bitmap->chunks = DEVFS_BITMAP_INITIAL_SIZE;
  51         bitmap->bitmap = kmalloc(bitmap->chunks * sizeof(u_long),
  52                                  M_DEVFS, M_WAITOK);
  53         memset(bitmap->bitmap, -1, bitmap->chunks * sizeof(u_long));
  54 }
  55
  56
  57 void
  58 devfs_clone_bitmap_uninit(struct devfs_bitmap *bitmap)
  59 {
  60         kfree(bitmap->bitmap, M_DEVFS);
  61 }
  62
  63
  64 void
  65 devfs_clone_bitmap_resize(struct devfs_bitmap *bitmap, int newchunks)
  66 {
  67         int oldchunks = bitmap->chunks;
  68
  69         bitmap->chunks = newchunks + 2;
  70         bitmap->bitmap = krealloc(bitmap->bitmap,
  71                                   sizeof(u_long) * bitmap->chunks,
  72                                   M_DEVFS, M_WAITOK);
  73         memset(bitmap->bitmap + oldchunks, -1,
  74                sizeof(u_long) * (bitmap->chunks - oldchunks));
  75 }
  76
  77
  78 int
  79 devfs_clone_bitmap_fff(struct devfs_bitmap *bitmap)
  80 {
  81         u_long curbitmap;
  82         int bit, i;
  83         int chunks;
  84
  85         chunks = bitmap->chunks;
  86
  87         for (i = 0; i < chunks + 1; i++) {
  88                 if (i == chunks)
  89                         devfs_clone_bitmap_resize(bitmap, i);
  90                 curbitmap = bitmap->bitmap[i];
  91
  92                 if (curbitmap) {
  93                         curbitmap &= (~curbitmap)+1;
  94                         for (bit = 1; curbitmap != 1; bit++)
  95                                 curbitmap >>= 1;
  96
  97                         return (bit - 1 + (i << 3) * sizeof(curbitmap));
  98                 }
  99         }
 100
 101         /*
 102          * NOT REACHED
 103          */
 104         panic("devfs_clone_bitmap_fff");
 105         return -1;
 106 }
 107
 108
 109 int
 110 devfs_clone_bitmap_chk(struct devfs_bitmap *bitmap, int unit)
 111 {
 112         int chunk;
 113
 114         chunk = unit / (sizeof(u_long) * 8);
 115         unit -= chunk * (sizeof(u_long) * 8);
 116
 117         if (chunk >= bitmap->chunks)
 118                 return 1;
 119
 120         return !((bitmap->bitmap[chunk]) & (1 << unit));
 121 }
 122
 123
 124 void
 125 devfs_clone_bitmap_set(struct devfs_bitmap *bitmap, int unit)
 126 {
 127         int chunk;
 128
 129         chunk = unit / (sizeof(u_long) * 8);
 130         unit -= chunk * (sizeof(u_long) * 8);
 131
 132         if (chunk >= bitmap->chunks)
 133                 devfs_clone_bitmap_resize(bitmap, chunk);
 134         bitmap->bitmap[chunk] &= ~(1<<unit);
 135 }
 136
 137
 138 void
 139 devfs_clone_bitmap_rst(struct devfs_bitmap *bitmap, int unit)
 140 {
 141         int chunk;
 142
 143         chunk = unit / (sizeof(u_long) * 8);
 144         unit -= chunk * (sizeof(u_long) * 8);
 145
 146         if (chunk >= bitmap->chunks)
 147                 return;
 148         bitmap->bitmap[chunk] |= (1 << unit);
 149 }
 150
 151
 152 int
 153 devfs_clone_bitmap_get(struct devfs_bitmap *bitmap, int limit)
 154 {
 155         int unit;
 156
 157         unit = devfs_clone_bitmap_fff(bitmap);
 158         if ((limit > 0) && (unit > limit))
 159                 return -1;
 160         devfs_clone_bitmap_set(bitmap, unit);
 161
 162         return unit;
 163 }
 164