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.

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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
43static inline int
44__ffs(int mask)
45{
46 return (ffs(mask) - 1);
47}
48

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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

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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

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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));

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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 if (size - bit <= BITS_PER_LONG)
169 return (size);
170 bit += BITS_PER_LONG;
171 addr++;
172 }
173 for (size -= bit; size >= BITS_PER_LONG;
174 size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) {
175 if (*addr == 0)
176 continue;
177 return (bit + __ffsl(*addr));
178 }
179 if (size) {
180 mask = (*addr) & BIT_MASK(size);
181 if (mask)
182 bit += __ffsl(mask);
183 else
184 bit += size;
185 }
186 return (bit);
187}
188

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197
198 if (offset >= size)
199 return (size);
200 pos = offset / BITS_PER_LONG;
201 offs = offset % BITS_PER_LONG;
202 bit = BITS_PER_LONG * pos;
203 addr += pos;
204 if (offs) {
205 mask = ~(*addr) & ~BIT_MASK(offs);
206 if (mask)
207 return (bit + __ffsl(mask));
208 if (size - bit <= BITS_PER_LONG)
209 return (size);
210 bit += BITS_PER_LONG;
211 addr++;
212 }
213 for (size -= bit; size >= BITS_PER_LONG;
214 size -= BITS_PER_LONG, bit += BITS_PER_LONG, addr++) {
215 if (~(*addr) == 0)
216 continue;
217 return (bit + __ffsl(~(*addr)));
218 }
219 if (size) {
220 mask = ~(*addr) & BIT_MASK(size);
221 if (mask)
222 bit += __ffsl(mask);
223 else
224 bit += size;
225 }
226 return (bit);
227}
228

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240{
241 int tail;
242 int len;
243
244 len = (size / BITS_PER_LONG) * sizeof(long);
245 memset(addr, 0xff, len);
246 tail = size & (BITS_PER_LONG - 1);
247 if (tail)
248 addr[size / BITS_PER_LONG] = BIT_MASK(tail);
249}
250
251static inline int
252bitmap_full(unsigned long *addr, int size)
253{
254 long mask;
255 int tail;
256 int len;
257 int i;
258
259 len = size / BITS_PER_LONG;
260 for (i = 0; i < len; i++)
261 if (addr[i] != ~0UL)
262 return (0);
263 tail = size & (BITS_PER_LONG - 1);
264 if (tail) {
265 mask = BIT_MASK(tail);
266 if ((addr[i] & mask) != mask)
267 return (0);
268 }
269 return (1);
270}
271
272static inline int
273bitmap_empty(unsigned long *addr, int size)
274{
275 long mask;
276 int tail;
277 int len;
278 int i;
279
280 len = size / BITS_PER_LONG;
281 for (i = 0; i < len; i++)
282 if (addr[i] != 0)
283 return (0);
284 tail = size & (BITS_PER_LONG - 1);
285 if (tail) {
286 mask = BIT_MASK(tail);
287 if ((addr[i] & mask) != 0)
288 return (0);
289 }
290 return (1);
291}
292
293#define NBLONG (NBBY * sizeof(long))
294
295#define __set_bit(i, a) \
296 atomic_set_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG))
297
298#define set_bit(i, a) \
299 atomic_set_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG))
300
301#define __clear_bit(i, a) \
302 atomic_clear_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG))
303
304#define clear_bit(i, a) \
305 atomic_clear_long(&((volatile long *)(a))[(i)/NBLONG], 1UL << ((i) % NBLONG))
306
307#define test_bit(i, a) \
308 !!(atomic_load_acq_long(&((volatile long *)(a))[(i)/NBLONG]) & \
309 (1UL << ((i) % NBLONG)))
310
311static inline long
312test_and_clear_bit(long bit, long *var)
313{
314 long val;
315
316 var += bit / (sizeof(long) * NBBY);
317 bit %= sizeof(long) * NBBY;
318 bit = (1UL << bit);
319 do {
320 val = *(volatile long *)var;
321 } while (atomic_cmpset_long(var, val, val & ~bit) == 0);
322
323 return !!(val & bit);
324}
325
326static inline long
327test_and_set_bit(long bit, long *var)
328{
329 long val;
330
331 var += bit / (sizeof(long) * NBBY);
332 bit %= sizeof(long) * NBBY;
333 bit = (1UL << bit);
334 do {
335 val = *(volatile long *)var;
336 } while (atomic_cmpset_long(var, val, val | bit) == 0);
337
338 return !!(val & bit);
339}
340
341
342#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) % BITS_PER_LONG))
343#define BITMAP_LAST_WORD_MASK(nbits) \
344( \
345 ((nbits) % BITS_PER_LONG) ? \
346 (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL \
347)
348
349
350static inline void
351bitmap_set(unsigned long *map, int start, int nr)
352{
353 unsigned long *p = map + BIT_WORD(start);
354 const int size = start + nr;
355 int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
356 unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
357

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385 }
386 if (nr) {
387 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
388 *p &= ~mask_to_clear;
389 }
390}
391
392enum {
393 REG_OP_ISFREE, /* true if region is all zero bits */
394 REG_OP_ALLOC, /* set all bits in region */
395 REG_OP_RELEASE, /* clear all bits in region */
396};
397
398static int __reg_op(unsigned long *bitmap, int pos, int order, int reg_op)
399{
400 int nbits_reg; /* number of bits in region */
401 int index; /* index first long of region in bitmap */
402 int offset; /* bit offset region in bitmap[index] */
403 int nlongs_reg; /* num longs spanned by region in bitmap */
404 int nbitsinlong; /* num bits of region in each spanned long */
405 unsigned long mask; /* bitmask for one long of region */
406 int i; /* scans bitmap by longs */
407 int ret = 0; /* return value */
408
409 /*
410 * Either nlongs_reg == 1 (for small orders that fit in one long)
411 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
412 */
413 nbits_reg = 1 << order;
414 index = pos / BITS_PER_LONG;
415 offset = pos - (index * BITS_PER_LONG);
416 nlongs_reg = BITS_TO_LONGS(nbits_reg);
417 nbitsinlong = min(nbits_reg, BITS_PER_LONG);
418
419 /*
420 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
421 * overflows if nbitsinlong == BITS_PER_LONG.
422 */
423 mask = (1UL << (nbitsinlong - 1));
424 mask += mask - 1;
425 mask <<= offset;
426
427 switch (reg_op) {
428 case REG_OP_ISFREE:
429 for (i = 0; i < nlongs_reg; i++) {
430 if (bitmap[index + i] & mask)
431 goto done;
432 }
433 ret = 1; /* all bits in region free (zero) */
434 break;
435
436 case REG_OP_ALLOC:
437 for (i = 0; i < nlongs_reg; i++)
438 bitmap[index + i] |= mask;
439 break;
440
441 case REG_OP_RELEASE:
442 for (i = 0; i < nlongs_reg; i++)
443 bitmap[index + i] &= ~mask;
444 break;
445 }
446done:
447 return ret;
448}
449
450/**
451 * bitmap_find_free_region - find a contiguous aligned mem region
452 * @bitmap: array of unsigned longs corresponding to the bitmap
453 * @bits: number of bits in the bitmap
454 * @order: region size (log base 2 of number of bits) to find
455 *
456 * Find a region of free (zero) bits in a @bitmap of @bits bits and
457 * allocate them (set them to one). Only consider regions of length
458 * a power (@order) of two, aligned to that power of two, which
459 * makes the search algorithm much faster.
460 *
461 * Return the bit offset in bitmap of the allocated region,
462 * or -errno on failure.
463 */
464static inline int
465bitmap_find_free_region(unsigned long *bitmap, int bits, int order)
466{
467 int pos, end; /* scans bitmap by regions of size order */
468
469 for (pos = 0 ; (end = pos + (1 << order)) <= bits; pos = end) {
470 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
471 continue;
472 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
473 return pos;
474 }
475 return -ENOMEM;
476}
477
478/**
479 * bitmap_allocate_region - allocate bitmap region
480 * @bitmap: array of unsigned longs corresponding to the bitmap
481 * @pos: beginning of bit region to allocate
482 * @order: region size (log base 2 of number of bits) to allocate
483 *
484 * Allocate (set bits in) a specified region of a bitmap.
485 *
486 * Return 0 on success, or %-EBUSY if specified region wasn't
487 * free (not all bits were zero).
488 */
489
490static inline int
491bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
492{
493 if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
494 return -EBUSY;
495 __reg_op(bitmap, pos, order, REG_OP_ALLOC);
496 return 0;
497}
498
499/**
500 * bitmap_release_region - release allocated bitmap region
501 * @bitmap: array of unsigned longs corresponding to the bitmap
502 * @pos: beginning of bit region to release
503 * @order: region size (log base 2 of number of bits) to release
504 *
505 * This is the complement to __bitmap_find_free_region() and releases
506 * the found region (by clearing it in the bitmap).
507 *
508 * No return value.
509 */
510static inline void
511bitmap_release_region(unsigned long *bitmap, int pos, int order)
512{
513 __reg_op(bitmap, pos, order, REG_OP_RELEASE);
514}
515
516
517#define for_each_set_bit(bit, addr, size) \
518 for ((bit) = find_first_bit((addr), (size)); \
519 (bit) < (size); \
520 (bit) = find_next_bit((addr), (size), (bit) + 1))
521
522#endif /* _LINUX_BITOPS_H_ */