bitops.h revision 219820
1/*- 2 * Copyright (c) 2010 Isilon Systems, Inc. 3 * Copyright (c) 2010 iX Systems, Inc. 4 * Copyright (c) 2010 Panasas, Inc. 5 * All rights reserved. 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 * 1. Redistributions of source code must retain the above copyright 11 * notice unmodified, this list of conditions, and the following 12 * disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28#ifndef _LINUX_BITOPS_H_ 29#define _LINUX_BITOPS_H_ 30 31#ifdef __LP64__ 32#define BITS_PER_LONG 64 33#else 34#define BITS_PER_LONG 32 35#endif 36#define BIT_MASK(n) (~0UL >> (BITS_PER_LONG - (n))) 37#define BITS_TO_LONGS(n) howmany((n), BITS_PER_LONG) 38 39static inline int 40__ffs(int mask) 41{ 42 return (ffs(mask) - 1); 43} 44 45static inline int 46__fls(int mask) 47{ 48 return (fls(mask) - 1); 49} 50 51static inline int 52__ffsl(long mask) 53{ 54 return (ffsl(mask) - 1); 55} 56 57static inline int 58__flsl(long mask) 59{ 60 return (flsl(mask) - 1); 61} 62 63 64#define ffz(mask) __ffs(~(mask)) 65 66static inline unsigned long 67find_first_bit(unsigned long *addr, unsigned long size) 68{ 69 long mask; 70 int bit; 71 72 for (bit = 0; size >= BITS_PER_LONG; 73 size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 74 if (*addr == 0) 75 continue; 76 return (bit + __ffsl(*addr)); 77 } 78 if (size) { 79 mask = (*addr) & BIT_MASK(size); 80 if (mask) 81 bit += __ffsl(mask); 82 else 83 bit += size; 84 } 85 return (bit); 86} 87 88static inline unsigned long 89find_first_zero_bit(unsigned long *addr, unsigned long size) 90{ 91 long mask; 92 int bit; 93 94 for (bit = 0; size >= BITS_PER_LONG; 95 size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 96 if (~(*addr) == 0) 97 continue; 98 return (bit + __ffsl(~(*addr))); 99 } 100 if (size) { 101 mask = ~(*addr) & BIT_MASK(size); 102 if (mask) 103 bit += __ffsl(mask); 104 else 105 bit += size; 106 } 107 return (bit); 108} 109 110static inline unsigned long 111find_last_bit(unsigned long *addr, unsigned long size) 112{ 113 long mask; 114 int offs; 115 int bit; 116 int pos; 117 118 pos = size / BITS_PER_LONG; 119 offs = size % BITS_PER_LONG; 120 bit = BITS_PER_LONG * pos; 121 addr += pos; 122 if (offs) { 123 mask = (*addr) & BIT_MASK(offs); 124 if (mask) 125 return (bit + __flsl(mask)); 126 } 127 while (--pos) { 128 addr--; 129 bit -= BITS_PER_LONG; 130 if (*addr) 131 return (bit + __flsl(mask)); 132 } 133 return (size); 134} 135 136static inline unsigned long 137find_next_bit(unsigned long *addr, unsigned long size, unsigned long offset) 138{ 139 long mask; 140 int offs; 141 int bit; 142 int pos; 143 144 if (offset >= size) 145 return (size); 146 pos = offset / BITS_PER_LONG; 147 offs = offset % BITS_PER_LONG; 148 bit = BITS_PER_LONG * pos; 149 addr += pos; 150 if (offs) { 151 mask = (*addr) & ~BIT_MASK(offs); 152 if (mask) 153 return (bit + __ffsl(mask)); 154 bit += BITS_PER_LONG; 155 addr++; 156 } 157 for (size -= bit; size >= BITS_PER_LONG; 158 size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 159 if (*addr == 0) 160 continue; 161 return (bit + __ffsl(*addr)); 162 } 163 if (size) { 164 mask = (*addr) & BIT_MASK(size); 165 if (mask) 166 bit += __ffsl(mask); 167 else 168 bit += size; 169 } 170 return (bit); 171} 172 173static inline unsigned long 174find_next_zero_bit(unsigned long *addr, unsigned long size, 175 unsigned long offset) 176{ 177 long mask; 178 int offs; 179 int bit; 180 int pos; 181 182 if (offset >= size) 183 return (size); 184 pos = offset / BITS_PER_LONG; 185 offs = offset % BITS_PER_LONG; 186 bit = BITS_PER_LONG * pos; 187 addr += pos; 188 if (offs) { 189 mask = ~(*addr) & ~BIT_MASK(offs); 190 if (mask) 191 return (bit + __ffsl(mask)); 192 bit += BITS_PER_LONG; 193 addr++; 194 } 195 for (size -= bit; size >= BITS_PER_LONG; 196 size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 197 if (~(*addr) == 0) 198 continue; 199 return (bit + __ffsl(~(*addr))); 200 } 201 if (size) { 202 mask = ~(*addr) & BIT_MASK(size); 203 if (mask) 204 bit += __ffsl(mask); 205 else 206 bit += size; 207 } 208 return (bit); 209} 210 211static inline void 212bitmap_zero(unsigned long *addr, int size) 213{ 214 int len; 215 216 len = BITS_TO_LONGS(size) * sizeof(long); 217 memset(addr, 0, len); 218} 219 220static inline void 221bitmap_fill(unsigned long *addr, int size) 222{ 223 int tail; 224 int len; 225 226 len = (size / BITS_PER_LONG) * sizeof(long); 227 memset(addr, 0xff, len); 228 tail = size & (BITS_PER_LONG - 1); 229 if (tail) 230 addr[size / BITS_PER_LONG] = BIT_MASK(tail); 231} 232 233static inline int 234bitmap_full(unsigned long *addr, int size) 235{ 236 long mask; 237 int tail; 238 int len; 239 int i; 240 241 len = size / BITS_PER_LONG; 242 for (i = 0; i < len; i++) 243 if (addr[i] != ~0UL) 244 return (0); 245 tail = size & (BITS_PER_LONG - 1); 246 if (tail) { 247 mask = BIT_MASK(tail); 248 if ((addr[i] & mask) != mask) 249 return (0); 250 } 251 return (1); 252} 253 254static inline int 255bitmap_empty(unsigned long *addr, int size) 256{ 257 long mask; 258 int tail; 259 int len; 260 int i; 261 262 len = size / BITS_PER_LONG; 263 for (i = 0; i < len; i++) 264 if (addr[i] != 0) 265 return (0); 266 tail = size & (BITS_PER_LONG - 1); 267 if (tail) { 268 mask = BIT_MASK(tail); 269 if ((addr[i] & mask) != 0) 270 return (0); 271 } 272 return (1); 273} 274 275#define NBINT (NBBY * sizeof(int)) 276 277#define set_bit(i, a) \ 278 atomic_set_int(&((volatile int *)(a))[(i)/NBINT], 1 << (i) % NBINT) 279 280#define clear_bit(i, a) \ 281 atomic_clear_int(&((volatile int *)(a))[(i)/NBINT], 1 << (i) % NBINT) 282 283#define test_bit(i, a) \ 284 !!(atomic_load_acq_int(&((volatile int *)(a))[(i)/NBINT]) & 1 << ((i) % NBINT)) 285 286static inline long 287test_and_clear_bit(long bit, long *var) 288{ 289 long val; 290 291 bit = 1 << bit; 292 do { 293 val = *(volatile long *)var; 294 } while (atomic_cmpset_long(var, val, val & ~bit) == 0); 295 296 return !!(val & bit); 297} 298 299static inline long 300test_and_set_bit(long bit, long *var) 301{ 302 long val; 303 304 bit = 1 << bit; 305 do { 306 val = *(volatile long *)var; 307 } while (atomic_cmpset_long(var, val, val | bit) == 0); 308 309 return !!(val & bit); 310} 311 312#endif /* _LINUX_BITOPS_H_ */ 313