1 /*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice unmodified, this list of conditions, and the following
13 * disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29 #ifndef _LINUX_BITOPS_H_
30 #define _LINUX_BITOPS_H_
31
32 #ifdef __LP64__
33 #define BITS_PER_LONG 64
34 #else
35 #define BITS_PER_LONG 32
36 #endif
37 #define BIT_MASK(n) (~0UL >> (BITS_PER_LONG - (n)))
38 #define BITS_TO_LONGS(n) howmany((n), BITS_PER_LONG)
39 #define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
40
41 #define BITS_PER_BYTE 8
42
43 static inline int
__ffs(int mask)44 __ffs(int mask)
45 {
46 return (ffs(mask) - 1);
47 }
48
49 static inline int
__fls(int mask)50 __fls(int mask)
51 {
52 return (fls(mask) - 1);
53 }
54
55 static inline int
__ffsl(long mask)56 __ffsl(long mask)
57 {
58 return (ffsl(mask) - 1);
59 }
60
61 static inline int
__flsl(long mask)62 __flsl(long mask)
63 {
64 return (flsl(mask) - 1);
65 }
66
67
68 #define ffz(mask) __ffs(~(mask))
69
get_count_order(unsigned int count)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
find_first_bit(unsigned long * addr,unsigned long size)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
find_first_zero_bit(unsigned long * addr,unsigned long size)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
find_last_bit(unsigned long * addr,unsigned long size)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(*addr));
146 }
147 return (size);
148 }
149
150 static inline unsigned long
find_next_bit(unsigned long * addr,unsigned long size,unsigned long offset)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
find_next_zero_bit(unsigned long * addr,unsigned long size,unsigned long offset)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
bitmap_zero(unsigned long * addr,int size)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
bitmap_fill(unsigned long * addr,int size)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
bitmap_full(unsigned long * addr,int size)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
bitmap_empty(unsigned long * addr,int size)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], 1UL << ((i) % NBLONG))
293
294 #define set_bit(i, a) \
295 atomic_set_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG))
296
297 #define __clear_bit(i, a) \
298 atomic_clear_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG))
299
300 #define clear_bit(i, a) \
301 atomic_clear_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG))
302
303 #define test_bit(i, a) \
304 !!(atomic_load_acq_long(&((volatile long *)(a))[(i)/NBLONG]) & \
305 (1UL << ((i) % NBLONG)))
306
307 static inline long
test_and_clear_bit(long bit,long * var)308 test_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
322 static inline long
test_and_set_bit(long bit,long * var)323 test_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
346 static inline void
bitmap_set(unsigned long * map,int start,int nr)347 bitmap_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
367 static inline void
bitmap_clear(unsigned long * map,int start,int nr)368 bitmap_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
388 enum {
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
__reg_op(unsigned long * bitmap,int pos,int order,int reg_op)394 static 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 }
442 done:
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 */
460 static inline int
bitmap_find_free_region(unsigned long * bitmap,int bits,int order)461 bitmap_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
486 static inline int
bitmap_allocate_region(unsigned long * bitmap,int pos,int order)487 bitmap_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 */
506 static inline void
bitmap_release_region(unsigned long * bitmap,int pos,int order)507 bitmap_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