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 <machine/limits.h> 39 #include <sys/devfs.h> 40 41 MALLOC_DECLARE(M_DEVFS); 42 43 /* 44 * DEVFS clone bitmap functions 45 */ 46 void 47 devfs_clone_bitmap_init(struct devfs_bitmap *bitmap) 48 { 49 bitmap->chunks = DEVFS_BITMAP_INITIAL_SIZE; 50 bitmap->bitmap = kmalloc(bitmap->chunks * sizeof(u_long), 51 M_DEVFS, M_WAITOK); 52 memset(bitmap->bitmap, -1, bitmap->chunks * sizeof(u_long)); 53 } 54 55 56 void 57 devfs_clone_bitmap_uninit(struct devfs_bitmap *bitmap) 58 { 59 kfree(bitmap->bitmap, M_DEVFS); 60 } 61 62 63 void 64 devfs_clone_bitmap_resize(struct devfs_bitmap *bitmap, int newchunks) 65 { 66 int oldchunks = bitmap->chunks; 67 68 bitmap->chunks = newchunks + 2; 69 bitmap->bitmap = krealloc(bitmap->bitmap, 70 sizeof(u_long) * bitmap->chunks, 71 M_DEVFS, M_WAITOK); 72 memset(bitmap->bitmap + oldchunks, -1, 73 sizeof(u_long) * (bitmap->chunks - oldchunks)); 74 } 75 76 77 int 78 devfs_clone_bitmap_fff(struct devfs_bitmap *bitmap) 79 { 80 u_long curbitmap; 81 int bit, i; 82 int chunks; 83 84 chunks = bitmap->chunks; 85 86 for (i = 0; i < chunks + 1; i++) { 87 if (i == chunks) 88 devfs_clone_bitmap_resize(bitmap, i); 89 curbitmap = bitmap->bitmap[i]; 90 91 if (curbitmap) { 92 curbitmap &= (~curbitmap)+1; 93 for (bit = 1; curbitmap != 1; bit++) 94 curbitmap >>= 1; 95 96 return (bit - 1 + (i << 3) * sizeof(curbitmap)); 97 } 98 } 99 100 /* 101 * NOT REACHED 102 */ 103 panic("devfs_clone_bitmap_fff"); 104 return -1; 105 } 106 107 108 int 109 devfs_clone_bitmap_chk(struct devfs_bitmap *bitmap, int unit) 110 { 111 int chunk; 112 113 chunk = unit / (sizeof(u_long) * 8); 114 unit -= chunk * (sizeof(u_long) * 8); 115 116 if (chunk >= bitmap->chunks) 117 return 1; 118 119 return !((bitmap->bitmap[chunk]) & (1 << unit)); 120 } 121 122 123 void 124 devfs_clone_bitmap_set(struct devfs_bitmap *bitmap, int unit) 125 { 126 int chunk; 127 128 chunk = unit / (sizeof(u_long) * 8); 129 unit -= chunk * (sizeof(u_long) * 8); 130 131 if (chunk >= bitmap->chunks) 132 devfs_clone_bitmap_resize(bitmap, chunk); 133 bitmap->bitmap[chunk] &= ~(1<<unit); 134 } 135 136 /* 137 * Deallocate a unit number. We must synchronize any destroy_dev()'s 138 * the device called before we clear the bitmap bit to avoid races 139 * against a new clone. 140 */ 141 void 142 devfs_clone_bitmap_put(struct devfs_bitmap *bitmap, int unit) 143 { 144 int chunk; 145 146 devfs_config(); 147 148 chunk = unit / (sizeof(u_long) * 8); 149 unit -= chunk * (sizeof(u_long) * 8); 150 151 if (chunk >= bitmap->chunks) 152 return; 153 bitmap->bitmap[chunk] |= (1 << unit); 154 } 155 156 /* 157 * Allocate a unit number for a device 158 */ 159 int 160 devfs_clone_bitmap_get(struct devfs_bitmap *bitmap, int limit) 161 { 162 int unit; 163 164 unit = devfs_clone_bitmap_fff(bitmap); 165 if ((limit > 0) && (unit > limit)) 166 return -1; 167 devfs_clone_bitmap_set(bitmap, unit); 168 169 return unit; 170 } 171 172