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 * Deallocate a unit number. We must synchronize any destroy_dev()'s 139 * the device called before we clear the bitmap bit to avoid races 140 * against a new clone. 141 */ 142 void 143 devfs_clone_bitmap_put(struct devfs_bitmap *bitmap, int unit) 144 { 145 int chunk; 146 147 devfs_config(); 148 149 chunk = unit / (sizeof(u_long) * 8); 150 unit -= chunk * (sizeof(u_long) * 8); 151 152 if (chunk >= bitmap->chunks) 153 return; 154 bitmap->bitmap[chunk] |= (1 << unit); 155 } 156 157 /* 158 * Allocate a unit number for a device 159 */ 160 int 161 devfs_clone_bitmap_get(struct devfs_bitmap *bitmap, int limit) 162 { 163 int unit; 164 165 unit = devfs_clone_bitmap_fff(bitmap); 166 if ((limit > 0) && (unit > limit)) 167 return -1; 168 devfs_clone_bitmap_set(bitmap, unit); 169 170 return unit; 171 } 172 173