bitops.h revision 277396
1178620Smarcel/*- 2178620Smarcel * Copyright (c) 2010 Isilon Systems, Inc. 3178620Smarcel * Copyright (c) 2010 iX Systems, Inc. 4178620Smarcel * Copyright (c) 2010 Panasas, Inc. 5178620Smarcel * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd. 6178620Smarcel * All rights reserved. 7178620Smarcel * 8178620Smarcel * Redistribution and use in source and binary forms, with or without 9178620Smarcel * modification, are permitted provided that the following conditions 10178620Smarcel * are met: 11178620Smarcel * 1. Redistributions of source code must retain the above copyright 12178620Smarcel * notice unmodified, this list of conditions, and the following 13178620Smarcel * disclaimer. 14178620Smarcel * 2. Redistributions in binary form must reproduce the above copyright 15178620Smarcel * notice, this list of conditions and the following disclaimer in the 16178620Smarcel * documentation and/or other materials provided with the distribution. 17178620Smarcel * 18178620Smarcel * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19178620Smarcel * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20178620Smarcel * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21178620Smarcel * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22178620Smarcel * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23178620Smarcel * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24178620Smarcel * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25178620Smarcel * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26178620Smarcel * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27178620Smarcel * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28178620Smarcel */ 29178620Smarcel#ifndef _LINUX_BITOPS_H_ 30178620Smarcel#define _LINUX_BITOPS_H_ 31178620Smarcel 32178620Smarcel#ifdef __LP64__ 33178620Smarcel#define BITS_PER_LONG 64 34178620Smarcel#else 35178620Smarcel#define BITS_PER_LONG 32 36178620Smarcel#endif 37178620Smarcel#define BIT_MASK(n) (~0UL >> (BITS_PER_LONG - (n))) 38178620Smarcel#define BITS_TO_LONGS(n) howmany((n), BITS_PER_LONG) 39178620Smarcel#define BIT_WORD(nr) ((nr) / BITS_PER_LONG) 40178620Smarcel 41178620Smarcel#define BITS_PER_BYTE 8 42178620Smarcel 43178620Smarcelstatic inline int 44178620Smarcel__ffs(int mask) 45178620Smarcel{ 46178620Smarcel return (ffs(mask) - 1); 47178620Smarcel} 48178620Smarcel 49178620Smarcelstatic inline int 50178620Smarcel__fls(int mask) 51178620Smarcel{ 52178620Smarcel return (fls(mask) - 1); 53178620Smarcel} 54178620Smarcel 55178620Smarcelstatic inline int 56178620Smarcel__ffsl(long mask) 57178620Smarcel{ 58178620Smarcel return (ffsl(mask) - 1); 59178620Smarcel} 60178620Smarcel 61178620Smarcelstatic inline int 62178620Smarcel__flsl(long mask) 63178620Smarcel{ 64178620Smarcel return (flsl(mask) - 1); 65178620Smarcel} 66178620Smarcel 67178620Smarcel 68178620Smarcel#define ffz(mask) __ffs(~(mask)) 69178620Smarcel 70178620Smarcelstatic inline int get_count_order(unsigned int count) 71178620Smarcel{ 72178620Smarcel int order; 73178620Smarcel 74178620Smarcel order = fls(count) - 1; 75178620Smarcel if (count & (count - 1)) 76178620Smarcel order++; 77178620Smarcel return order; 78178620Smarcel} 79178620Smarcel 80178620Smarcelstatic inline unsigned long 81178620Smarcelfind_first_bit(unsigned long *addr, unsigned long size) 82178620Smarcel{ 83178620Smarcel long mask; 84178620Smarcel int bit; 85178620Smarcel 86178620Smarcel for (bit = 0; size >= BITS_PER_LONG; 87178620Smarcel size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 88178620Smarcel if (*addr == 0) 89178620Smarcel continue; 90178620Smarcel return (bit + __ffsl(*addr)); 91178620Smarcel } 92178620Smarcel if (size) { 93178620Smarcel mask = (*addr) & BIT_MASK(size); 94178620Smarcel if (mask) 95178620Smarcel bit += __ffsl(mask); 96178620Smarcel else 97178620Smarcel bit += size; 98178620Smarcel } 99178620Smarcel return (bit); 100178620Smarcel} 101178620Smarcel 102178620Smarcelstatic inline unsigned long 103178620Smarcelfind_first_zero_bit(unsigned long *addr, unsigned long size) 104178620Smarcel{ 105178620Smarcel long mask; 106178620Smarcel int bit; 107178620Smarcel 108178620Smarcel for (bit = 0; size >= BITS_PER_LONG; 109178620Smarcel size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 110178620Smarcel if (~(*addr) == 0) 111178620Smarcel continue; 112178620Smarcel return (bit + __ffsl(~(*addr))); 113178620Smarcel } 114178620Smarcel if (size) { 115178620Smarcel mask = ~(*addr) & BIT_MASK(size); 116178620Smarcel if (mask) 117178620Smarcel bit += __ffsl(mask); 118178620Smarcel else 119178620Smarcel bit += size; 120178620Smarcel } 121178620Smarcel return (bit); 122178620Smarcel} 123178620Smarcel 124178620Smarcelstatic inline unsigned long 125178620Smarcelfind_last_bit(unsigned long *addr, unsigned long size) 126178620Smarcel{ 127178620Smarcel long mask; 128178620Smarcel int offs; 129178620Smarcel int bit; 130178620Smarcel int pos; 131178620Smarcel 132178620Smarcel pos = size / BITS_PER_LONG; 133178620Smarcel offs = size % BITS_PER_LONG; 134178620Smarcel bit = BITS_PER_LONG * pos; 135178620Smarcel addr += pos; 136178620Smarcel if (offs) { 137178620Smarcel mask = (*addr) & BIT_MASK(offs); 138178620Smarcel if (mask) 139178620Smarcel return (bit + __flsl(mask)); 140178620Smarcel } 141178620Smarcel while (--pos) { 142178620Smarcel addr--; 143178620Smarcel bit -= BITS_PER_LONG; 144178620Smarcel if (*addr) 145178620Smarcel return (bit + __flsl(mask)); 146178620Smarcel } 147178620Smarcel return (size); 148178620Smarcel} 149178620Smarcel 150178620Smarcelstatic inline unsigned long 151178620Smarcelfind_next_bit(unsigned long *addr, unsigned long size, unsigned long offset) 152178620Smarcel{ 153178620Smarcel long mask; 154178620Smarcel int offs; 155178620Smarcel int bit; 156178620Smarcel int pos; 157178620Smarcel 158178620Smarcel if (offset >= size) 159178620Smarcel return (size); 160178620Smarcel pos = offset / BITS_PER_LONG; 161178620Smarcel offs = offset % BITS_PER_LONG; 162178620Smarcel bit = BITS_PER_LONG * pos; 163178620Smarcel addr += pos; 164178620Smarcel if (offs) { 165178620Smarcel mask = (*addr) & ~BIT_MASK(offs); 166178620Smarcel if (mask) 167178620Smarcel return (bit + __ffsl(mask)); 168178620Smarcel bit += BITS_PER_LONG; 169178620Smarcel addr++; 170178620Smarcel } 171178620Smarcel for (size -= bit; size >= BITS_PER_LONG; 172178620Smarcel size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 173178620Smarcel if (*addr == 0) 174178620Smarcel continue; 175178620Smarcel return (bit + __ffsl(*addr)); 176178620Smarcel } 177178620Smarcel if (size) { 178178620Smarcel mask = (*addr) & BIT_MASK(size); 179178620Smarcel if (mask) 180178620Smarcel bit += __ffsl(mask); 181178620Smarcel else 182178620Smarcel bit += size; 183178620Smarcel } 184178620Smarcel return (bit); 185178620Smarcel} 186178620Smarcel 187178620Smarcelstatic inline unsigned long 188178620Smarcelfind_next_zero_bit(unsigned long *addr, unsigned long size, 189178620Smarcel unsigned long offset) 190178620Smarcel{ 191178620Smarcel long mask; 192178620Smarcel int offs; 193178620Smarcel int bit; 194178620Smarcel int pos; 195178620Smarcel 196178620Smarcel if (offset >= size) 197178620Smarcel return (size); 198178620Smarcel pos = offset / BITS_PER_LONG; 199178620Smarcel offs = offset % BITS_PER_LONG; 200178620Smarcel bit = BITS_PER_LONG * pos; 201178620Smarcel addr += pos; 202178620Smarcel if (offs) { 203178620Smarcel mask = ~(*addr) & ~BIT_MASK(offs); 204178620Smarcel if (mask) 205178620Smarcel return (bit + __ffsl(mask)); 206178620Smarcel bit += BITS_PER_LONG; 207178620Smarcel addr++; 208178620Smarcel } 209178620Smarcel for (size -= bit; size >= BITS_PER_LONG; 210178620Smarcel size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) { 211178620Smarcel if (~(*addr) == 0) 212178620Smarcel continue; 213178620Smarcel return (bit + __ffsl(~(*addr))); 214178620Smarcel } 215178620Smarcel if (size) { 216178620Smarcel mask = ~(*addr) & BIT_MASK(size); 217178620Smarcel if (mask) 218178620Smarcel bit += __ffsl(mask); 219178620Smarcel else 220178620Smarcel bit += size; 221178620Smarcel } 222178620Smarcel return (bit); 223178620Smarcel} 224178620Smarcel 225178620Smarcelstatic inline void 226178620Smarcelbitmap_zero(unsigned long *addr, int size) 227178620Smarcel{ 228178620Smarcel int len; 229178620Smarcel 230178620Smarcel len = BITS_TO_LONGS(size) * sizeof(long); 231178620Smarcel memset(addr, 0, len); 232178620Smarcel} 233178620Smarcel 234178620Smarcelstatic inline void 235178620Smarcelbitmap_fill(unsigned long *addr, int size) 236178620Smarcel{ 237178620Smarcel int tail; 238178620Smarcel int len; 239178620Smarcel 240178620Smarcel len = (size / BITS_PER_LONG) * sizeof(long); 241178620Smarcel memset(addr, 0xff, len); 242178620Smarcel tail = size & (BITS_PER_LONG - 1); 243178620Smarcel if (tail) 244178620Smarcel addr[size / BITS_PER_LONG] = BIT_MASK(tail); 245178620Smarcel} 246178620Smarcel 247178620Smarcelstatic inline int 248178620Smarcelbitmap_full(unsigned long *addr, int size) 249178620Smarcel{ 250178620Smarcel long mask; 251178620Smarcel int tail; 252178620Smarcel int len; 253178620Smarcel int i; 254178620Smarcel 255178620Smarcel len = size / BITS_PER_LONG; 256178620Smarcel for (i = 0; i < len; i++) 257178620Smarcel if (addr[i] != ~0UL) 258178620Smarcel return (0); 259178620Smarcel tail = size & (BITS_PER_LONG - 1); 260178620Smarcel if (tail) { 261178620Smarcel mask = BIT_MASK(tail); 262178620Smarcel if ((addr[i] & mask) != mask) 263178620Smarcel return (0); 264178620Smarcel } 265178620Smarcel return (1); 266178620Smarcel} 267178620Smarcel 268178620Smarcelstatic inline int 269178620Smarcelbitmap_empty(unsigned long *addr, int size) 270178620Smarcel{ 271178620Smarcel long mask; 272178620Smarcel int tail; 273178620Smarcel int len; 274178620Smarcel int i; 275178620Smarcel 276178620Smarcel len = size / BITS_PER_LONG; 277178620Smarcel for (i = 0; i < len; i++) 278178620Smarcel if (addr[i] != 0) 279178620Smarcel return (0); 280178620Smarcel tail = size & (BITS_PER_LONG - 1); 281178620Smarcel if (tail) { 282178620Smarcel mask = BIT_MASK(tail); 283178620Smarcel if ((addr[i] & mask) != 0) 284178620Smarcel return (0); 285178620Smarcel } 286178620Smarcel return (1); 287178620Smarcel} 288178620Smarcel 289178620Smarcel#define NBLONG (NBBY * sizeof(long)) 290178620Smarcel 291178620Smarcel#define __set_bit(i, a) \ 292178620Smarcel atomic_set_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG)) 293178620Smarcel 294178620Smarcel#define set_bit(i, a) \ 295178620Smarcel atomic_set_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG)) 296178620Smarcel 297178620Smarcel#define __clear_bit(i, a) \ 298178620Smarcel atomic_clear_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG)) 299178620Smarcel 300178620Smarcel#define clear_bit(i, a) \ 301178620Smarcel atomic_clear_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG)) 302178620Smarcel 303178620Smarcel#define test_bit(i, a) \ 304178620Smarcel !!(atomic_load_acq_long(&((volatile long *)(a))[(i)/NBLONG]) & \ 305178620Smarcel (1UL << ((i) % NBLONG))) 306178620Smarcel 307178620Smarcelstatic inline long 308test_and_clear_bit(long bit, long *var) 309{ 310 long val; 311 312 var += bit / (sizeof(long) * NBBY); 313 bit %= sizeof(long) * NBBY; 314 bit = (1UL << bit); 315 do { 316 val = *(volatile long *)var; 317 } while (atomic_cmpset_long(var, val, val & ~bit) == 0); 318 319 return !!(val & bit); 320} 321 322static inline long 323test_and_set_bit(long bit, long *var) 324{ 325 long val; 326 327 var += bit / (sizeof(long) * NBBY); 328 bit %= sizeof(long) * NBBY; 329 bit = (1UL << bit); 330 do { 331 val = *(volatile long *)var; 332 } while (atomic_cmpset_long(var, val, val | bit) == 0); 333 334 return !!(val & bit); 335} 336 337 338#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) % BITS_PER_LONG)) 339#define BITMAP_LAST_WORD_MASK(nbits) \ 340( \ 341 ((nbits) % BITS_PER_LONG) ? \ 342 (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL \ 343) 344 345 346static inline void 347bitmap_set(unsigned long *map, int start, int nr) 348{ 349 unsigned long *p = map + BIT_WORD(start); 350 const int size = start + nr; 351 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); 352 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); 353 354 while (nr - bits_to_set >= 0) { 355 *p |= mask_to_set; 356 nr -= bits_to_set; 357 bits_to_set = BITS_PER_LONG; 358 mask_to_set = ~0UL; 359 p++; 360 } 361 if (nr) { 362 mask_to_set &= BITMAP_LAST_WORD_MASK(size); 363 *p |= mask_to_set; 364 } 365} 366 367static inline void 368bitmap_clear(unsigned long *map, int start, int nr) 369{ 370 unsigned long *p = map + BIT_WORD(start); 371 const int size = start + nr; 372 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); 373 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); 374 375 while (nr - bits_to_clear >= 0) { 376 *p &= ~mask_to_clear; 377 nr -= bits_to_clear; 378 bits_to_clear = BITS_PER_LONG; 379 mask_to_clear = ~0UL; 380 p++; 381 } 382 if (nr) { 383 mask_to_clear &= BITMAP_LAST_WORD_MASK(size); 384 *p &= ~mask_to_clear; 385 } 386} 387 388enum { 389 REG_OP_ISFREE, /* true if region is all zero bits */ 390 REG_OP_ALLOC, /* set all bits in region */ 391 REG_OP_RELEASE, /* clear all bits in region */ 392}; 393 394static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op) 395{ 396 int nbits_reg; /* number of bits in region */ 397 int index; /* index first long of region in bitmap */ 398 int offset; /* bit offset region in bitmap[index] */ 399 int nlongs_reg; /* num longs spanned by region in bitmap */ 400 int nbitsinlong; /* num bits of region in each spanned long */ 401 unsigned long mask; /* bitmask for one long of region */ 402 int i; /* scans bitmap by longs */ 403 int ret = 0; /* return value */ 404 405 /* 406 * Either nlongs_reg == 1 (for small orders that fit in one long) 407 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.) 408 */ 409 nbits_reg = 1 << order; 410 index = pos / BITS_PER_LONG; 411 offset = pos - (index * BITS_PER_LONG); 412 nlongs_reg = BITS_TO_LONGS(nbits_reg); 413 nbitsinlong = min(nbits_reg, BITS_PER_LONG); 414 415 /* 416 * Can't do "mask = (1UL << nbitsinlong) - 1", as that 417 * overflows if nbitsinlong == BITS_PER_LONG. 418 */ 419 mask = (1UL << (nbitsinlong - 1)); 420 mask += mask - 1; 421 mask <<= offset; 422 423 switch (reg_op) { 424 case REG_OP_ISFREE: 425 for (i = 0; i < nlongs_reg; i++) { 426 if (bitmap[index + i] & mask) 427 goto done; 428 } 429 ret = 1; /* all bits in region free (zero) */ 430 break; 431 432 case REG_OP_ALLOC: 433 for (i = 0; i < nlongs_reg; i++) 434 bitmap[index + i] |= mask; 435 break; 436 437 case REG_OP_RELEASE: 438 for (i = 0; i < nlongs_reg; i++) 439 bitmap[index + i] &= ~mask; 440 break; 441 } 442done: 443 return ret; 444} 445 446/** 447 * bitmap_find_free_region - find a contiguous aligned mem region 448 * @bitmap: array of unsigned longs corresponding to the bitmap 449 * @bits: number of bits in the bitmap 450 * @order: region size (log base 2 of number of bits) to find 451 * 452 * Find a region of free (zero) bits in a @bitmap of @bits bits and 453 * allocate them (set them to one). Only consider regions of length 454 * a power (@order) of two, aligned to that power of two, which 455 * makes the search algorithm much faster. 456 * 457 * Return the bit offset in bitmap of the allocated region, 458 * or -errno on failure. 459 */ 460static inline int 461bitmap_find_free_region(unsigned long *bitmap, int bits, int order) 462{ 463 int pos, end; /* scans bitmap by regions of size order */ 464 465 for (pos = 0 ; (end = pos + (1 << order)) <= bits; pos = end) { 466 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 467 continue; 468 __reg_op(bitmap, pos, order, REG_OP_ALLOC); 469 return pos; 470 } 471 return -ENOMEM; 472} 473 474/** 475 * bitmap_allocate_region - allocate bitmap region 476 * @bitmap: array of unsigned longs corresponding to the bitmap 477 * @pos: beginning of bit region to allocate 478 * @order: region size (log base 2 of number of bits) to allocate 479 * 480 * Allocate (set bits in) a specified region of a bitmap. 481 * 482 * Return 0 on success, or %-EBUSY if specified region wasn't 483 * free (not all bits were zero). 484 */ 485 486static inline int 487bitmap_allocate_region(unsigned long *bitmap, int pos, int order) 488{ 489 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE)) 490 return -EBUSY; 491 __reg_op(bitmap, pos, order, REG_OP_ALLOC); 492 return 0; 493} 494 495/** 496 * bitmap_release_region - release allocated bitmap region 497 * @bitmap: array of unsigned longs corresponding to the bitmap 498 * @pos: beginning of bit region to release 499 * @order: region size (log base 2 of number of bits) to release 500 * 501 * This is the complement to __bitmap_find_free_region() and releases 502 * the found region (by clearing it in the bitmap). 503 * 504 * No return value. 505 */ 506static inline void 507bitmap_release_region(unsigned long *bitmap, int pos, int order) 508{ 509 __reg_op(bitmap, pos, order, REG_OP_RELEASE); 510} 511 512 513#define for_each_set_bit(bit, addr, size) \ 514 for ((bit) = find_first_bit((addr), (size)); \ 515 (bit) < (size); \ 516 (bit) = find_next_bit((addr), (size), (bit) + 1)) 517 518#endif /* _LINUX_BITOPS_H_ */ 519