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 #include <sys/types.h> 32 #include <sys/systm.h> 33 34 #ifdef __LP64__ 35 #define BITS_PER_LONG 64 36 #else 37 #define BITS_PER_LONG 32 38 #endif 39 #define BIT_MASK(n) (~0UL >> (BITS_PER_LONG - (n))) 40 #define BITS_TO_LONGS(n) howmany((n), BITS_PER_LONG) 41 #define BIT_WORD(nr) ((nr) / BITS_PER_LONG) 42 43 static inline int 44 __ffs(int mask) 45 { 46 return (ffs(mask) - 1); 47 } 48 49 static inline int 50 __fls(int mask) 51 { 52 return (fls(mask) - 1); 53 } 54 55 static inline int 56 __ffsl(long mask) 57 { 58 return (ffsl(mask) - 1); 59 } 60 61 static inline int 62 __flsl(long mask) 63 { 64 return (flsl(mask) - 1); 65 } 66 67 68 #define ffz(mask) __ffs(~(mask)) 69 70 static inline int get_count_order(unsigned int count) 71 { 72 int order; 73 74 order = fls(count) - 1; 75 if (count & (count - 1)) 76 order++; 77 return order; 78 } 79 80 static inline unsigned long 81 find_first_bit(unsigned long *addr, unsigned long size) 82 { 83 long mask; 84 int bit; 85 86 for (bit = 0; size >= BITS_PER_LONG; 87 size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 88 if (*addr == 0) 89 continue; 90 return (bit + __ffsl(*addr)); 91 } 92 if (size) { 93 mask = (*addr) & BIT_MASK(size); 94 if (mask) 95 bit += __ffsl(mask); 96 else 97 bit += size; 98 } 99 return (bit); 100 } 101 102 static inline unsigned long 103 find_first_zero_bit(unsigned long *addr, unsigned long size) 104 { 105 long mask; 106 int bit; 107 108 for (bit = 0; size >= BITS_PER_LONG; 109 size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 110 if (~(*addr) == 0) 111 continue; 112 return (bit + __ffsl(~(*addr))); 113 } 114 if (size) { 115 mask = ~(*addr) & BIT_MASK(size); 116 if (mask) 117 bit += __ffsl(mask); 118 else 119 bit += size; 120 } 121 return (bit); 122 } 123 124 static inline unsigned long 125 find_last_bit(unsigned long *addr, unsigned long size) 126 { 127 long mask; 128 int offs; 129 int bit; 130 int pos; 131 132 pos = size / BITS_PER_LONG; 133 offs = size % BITS_PER_LONG; 134 bit = BITS_PER_LONG * pos; 135 addr += pos; 136 if (offs) { 137 mask = (*addr) & BIT_MASK(offs); 138 if (mask) 139 return (bit + __flsl(mask)); 140 } 141 while (--pos) { 142 addr--; 143 bit -= BITS_PER_LONG; 144 if (*addr) 145 return (bit + __flsl(mask)); 146 } 147 return (size); 148 } 149 150 static inline unsigned long 151 find_next_bit(unsigned long *addr, unsigned long size, unsigned long offset) 152 { 153 long mask; 154 int offs; 155 int bit; 156 int pos; 157 158 if (offset >= size) 159 return (size); 160 pos = offset / BITS_PER_LONG; 161 offs = offset % BITS_PER_LONG; 162 bit = BITS_PER_LONG * pos; 163 addr += pos; 164 if (offs) { 165 mask = (*addr) & ~BIT_MASK(offs); 166 if (mask) 167 return (bit + __ffsl(mask)); 168 bit += BITS_PER_LONG; 169 addr++; 170 } 171 for (size -= bit; size >= BITS_PER_LONG; 172 size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 173 if (*addr == 0) 174 continue; 175 return (bit + __ffsl(*addr)); 176 } 177 if (size) { 178 mask = (*addr) & BIT_MASK(size); 179 if (mask) 180 bit += __ffsl(mask); 181 else 182 bit += size; 183 } 184 return (bit); 185 } 186 187 static inline unsigned long 188 find_next_zero_bit(unsigned long *addr, unsigned long size, 189 unsigned long offset) 190 { 191 long mask; 192 int offs; 193 int bit; 194 int pos; 195 196 if (offset >= size) 197 return (size); 198 pos = offset / BITS_PER_LONG; 199 offs = offset % BITS_PER_LONG; 200 bit = BITS_PER_LONG * pos; 201 addr += pos; 202 if (offs) { 203 mask = ~(*addr) & ~BIT_MASK(offs); 204 if (mask) 205 return (bit + __ffsl(mask)); 206 bit += BITS_PER_LONG; 207 addr++; 208 } 209 for (size -= bit; size >= BITS_PER_LONG; 210 size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 211 if (~(*addr) == 0) 212 continue; 213 return (bit + __ffsl(~(*addr))); 214 } 215 if (size) { 216 mask = ~(*addr) & BIT_MASK(size); 217 if (mask) 218 bit += __ffsl(mask); 219 else 220 bit += size; 221 } 222 return (bit); 223 } 224 225 static inline void 226 bitmap_zero(unsigned long *addr, int size) 227 { 228 int len; 229 230 len = BITS_TO_LONGS(size) * sizeof(long); 231 memset(addr, 0, len); 232 } 233 234 static inline void 235 bitmap_fill(unsigned long *addr, int size) 236 { 237 int tail; 238 int len; 239 240 len = (size / BITS_PER_LONG) * sizeof(long); 241 memset(addr, 0xff, len); 242 tail = size & (BITS_PER_LONG - 1); 243 if (tail) 244 addr[size / BITS_PER_LONG] = BIT_MASK(tail); 245 } 246 247 static inline int 248 bitmap_full(unsigned long *addr, int size) 249 { 250 long mask; 251 int tail; 252 int len; 253 int i; 254 255 len = size / BITS_PER_LONG; 256 for (i = 0; i < len; i++) 257 if (addr[i] != ~0UL) 258 return (0); 259 tail = size & (BITS_PER_LONG - 1); 260 if (tail) { 261 mask = BIT_MASK(tail); 262 if ((addr[i] & mask) != mask) 263 return (0); 264 } 265 return (1); 266 } 267 268 static inline int 269 bitmap_empty(unsigned long *addr, int size) 270 { 271 long mask; 272 int tail; 273 int len; 274 int i; 275 276 len = size / BITS_PER_LONG; 277 for (i = 0; i < len; i++) 278 if (addr[i] != 0) 279 return (0); 280 tail = size & (BITS_PER_LONG - 1); 281 if (tail) { 282 mask = BIT_MASK(tail); 283 if ((addr[i] & mask) != 0) 284 return (0); 285 } 286 return (1); 287 } 288 289 #define NBLONG (NBBY * sizeof(long)) 290 291 #define set_bit(i, a) \ 292 atomic_set_long(&((volatile long *)(a))[(i)/NBLONG], 1 << (i) % NBLONG) 293 294 #define clear_bit(i, a) \ 295 atomic_clear_long(&((volatile long *)(a))[(i)/NBLONG], 1 << (i) % NBLONG) 296 297 #define test_bit(i, a) \ 298 !!(atomic_load_acq_long(&((volatile long *)(a))[(i)/NBLONG]) & \ 299 1 << ((i) % NBLONG)) 300 301 static inline long 302 test_and_clear_bit(long bit, long *var) 303 { 304 long val; 305 306 var += bit / (sizeof(long) * NBBY); 307 bit %= sizeof(long) * NBBY; 308 bit = 1 << bit; 309 do { 310 val = *(volatile long *)var; 311 } while (atomic_cmpset_long(var, val, val & ~bit) == 0); 312 313 return !!(val & bit); 314 } 315 316 static inline long 317 test_and_set_bit(long bit, volatile unsigned long *var) 318 { 319 long val; 320 321 var += bit / (sizeof(long) * NBBY); 322 bit %= sizeof(long) * NBBY; 323 bit = 1 << bit; 324 do { 325 val = *(volatile long *)var; 326 } while (atomic_cmpset_long(var, val, val | bit) == 0); 327 328 return !!(val & bit); 329 } 330 331 332 #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) % BITS_PER_LONG)) 333 #define BITMAP_LAST_WORD_MASK(nbits) \ 334 ( \ 335 ((nbits) % BITS_PER_LONG) ? \ 336 (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL \ 337 ) 338 339 340 static inline void 341 bitmap_set(unsigned long *map, int start, int nr) 342 { 343 unsigned long *p = map + BIT_WORD(start); 344 const int size = start + nr; 345 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); 346 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); 347 348 while (nr - bits_to_set >= 0) { 349 *p |= mask_to_set; 350 nr -= bits_to_set; 351 bits_to_set = BITS_PER_LONG; 352 mask_to_set = ~0UL; 353 p++; 354 } 355 if (nr) { 356 mask_to_set &= BITMAP_LAST_WORD_MASK(size); 357 *p |= mask_to_set; 358 } 359 } 360 361 static inline void 362 bitmap_clear(unsigned long *map, int start, int nr) 363 { 364 unsigned long *p = map + BIT_WORD(start); 365 const int size = start + nr; 366 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); 367 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); 368 369 while (nr - bits_to_clear >= 0) { 370 *p &= ~mask_to_clear; 371 nr -= bits_to_clear; 372 bits_to_clear = BITS_PER_LONG; 373 mask_to_clear = ~0UL; 374 p++; 375 } 376 if (nr) { 377 mask_to_clear &= BITMAP_LAST_WORD_MASK(size); 378 *p &= ~mask_to_clear; 379 } 380 } 381 382 enum { 383 REG_OP_ISFREE, /* true if region is all zero bits */ 384 REG_OP_ALLOC, /* set all bits in region */ 385 REG_OP_RELEASE, /* clear all bits in region */ 386 }; 387 388 static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op) 389 { 390 int nbits_reg; /* number of bits in region */ 391 int index; /* index first long of region in bitmap */ 392 int offset; /* bit offset region in bitmap[index] */ 393 int nlongs_reg; /* num longs spanned by region in bitmap */ 394 int nbitsinlong; /* num bits of region in each spanned long */ 395 unsigned long mask; /* bitmask for one long of region */ 396 int i; /* scans bitmap by longs */ 397 int ret = 0; /* return value */ 398 399 /* 400 * Either nlongs_reg == 1 (for small orders that fit in one long) 401 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.) 402 */ 403 nbits_reg = 1 << order; 404 index = pos / BITS_PER_LONG; 405 offset = pos - (index * BITS_PER_LONG); 406 nlongs_reg = BITS_TO_LONGS(nbits_reg); 407 nbitsinlong = min(nbits_reg, BITS_PER_LONG); 408 409 /* 410 * Can't do "mask = (1UL << nbitsinlong) - 1", as that 411 * overflows if nbitsinlong == BITS_PER_LONG. 412 */ 413 mask = (1UL << (nbitsinlong - 1)); 414 mask += mask - 1; 415 mask <<= offset; 416 417 switch (reg_op) { 418 case REG_OP_ISFREE: 419 for (i = 0; i < nlongs_reg; i++) { 420 if (bitmap[index + i] & mask) 421 goto done; 422 } 423 ret = 1; /* all bits in region free (zero) */ 424 break; 425 426 case REG_OP_ALLOC: 427 for (i = 0; i < nlongs_reg; i++) 428 bitmap[index + i] |= mask; 429 break; 430 431 case REG_OP_RELEASE: 432 for (i = 0; i < nlongs_reg; i++) 433 bitmap[index + i] &= ~mask; 434 break; 435 } 436 done: 437 return ret; 438 } 439 440 /** 441 * bitmap_find_free_region - find a contiguous aligned mem region 442 * @bitmap: array of unsigned longs corresponding to the bitmap 443 * @bits: number of bits in the bitmap 444 * @order: region size (log base 2 of number of bits) to find 445 * 446 * Find a region of free (zero) bits in a @bitmap of @bits bits and 447 * allocate them (set them to one). Only consider regions of length 448 * a power (@order) of two, aligned to that power of two, which 449 * makes the search algorithm much faster. 450 * 451 * Return the bit offset in bitmap of the allocated region, 452 * or -errno on failure. 453 */ 454 static inline int 455 bitmap_find_free_region(unsigned long *bitmap, int bits, int order) 456 { 457 int pos, end; /* scans bitmap by regions of size order */ 458 459 for (pos = 0 ; (end = pos + (1 << order)) <= bits; pos = end) { 460 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 461 continue; 462 __reg_op(bitmap, pos, order, REG_OP_ALLOC); 463 return pos; 464 } 465 return -ENOMEM; 466 } 467 468 /** 469 * bitmap_release_region - release allocated bitmap region 470 * @bitmap: array of unsigned longs corresponding to the bitmap 471 * @pos: beginning of bit region to release 472 * @order: region size (log base 2 of number of bits) to release 473 * 474 * This is the complement to __bitmap_find_free_region() and releases 475 * the found region (by clearing it in the bitmap). 476 * 477 * No return value. 478 */ 479 static inline void 480 bitmap_release_region(unsigned long *bitmap, int pos, int order) 481 { 482 __reg_op(bitmap, pos, order, REG_OP_RELEASE); 483 } 484 485 #include <asm/bitops/non-atomic.h> 486 487 #endif /* _LINUX_BITOPS_H_ */ 488