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 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
189 static inline unsigned long
find_next_zero_bit(unsigned long * addr,unsigned long size,unsigned long offset)190 find_next_zero_bit(unsigned long *addr, unsigned long size,
191 unsigned long offset)
192 {
193 long mask;
194 int offs;
195 int bit;
196 int pos;
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
229 static inline void
bitmap_zero(unsigned long * addr,int size)230 bitmap_zero(unsigned long *addr, int size)
231 {
232 int len;
233
234 len = BITS_TO_LONGS(size) * sizeof(long);
235 memset(addr, 0, len);
236 }
237
238 static inline void
bitmap_fill(unsigned long * addr,int size)239 bitmap_fill(unsigned long *addr, int size)
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
251 static inline int
bitmap_full(unsigned long * addr,int size)252 bitmap_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
272 static inline int
bitmap_empty(unsigned long * addr,int size)273 bitmap_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
311 static inline long
test_and_clear_bit(long bit,long * var)312 test_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
326 static inline long
test_and_set_bit(long bit,long * var)327 test_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
350 static inline void
bitmap_set(unsigned long * map,int start,int nr)351 bitmap_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
358 while (nr - bits_to_set >= 0) {
359 *p |= mask_to_set;
360 nr -= bits_to_set;
361 bits_to_set = BITS_PER_LONG;
362 mask_to_set = ~0UL;
363 p++;
364 }
365 if (nr) {
366 mask_to_set &= BITMAP_LAST_WORD_MASK(size);
367 *p |= mask_to_set;
368 }
369 }
370
371 static inline void
bitmap_clear(unsigned long * map,int start,int nr)372 bitmap_clear(unsigned long *map, int start, int nr)
373 {
374 unsigned long *p = map + BIT_WORD(start);
375 const int size = start + nr;
376 int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
377 unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
378
379 while (nr - bits_to_clear >= 0) {
380 *p &= ~mask_to_clear;
381 nr -= bits_to_clear;
382 bits_to_clear = BITS_PER_LONG;
383 mask_to_clear = ~0UL;
384 p++;
385 }
386 if (nr) {
387 mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
388 *p &= ~mask_to_clear;
389 }
390 }
391
392 enum {
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
__reg_op(unsigned long * bitmap,int pos,int order,int reg_op)398 static 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 }
446 done:
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 */
464 static inline int
bitmap_find_free_region(unsigned long * bitmap,int bits,int order)465 bitmap_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
490 static inline int
bitmap_allocate_region(unsigned long * bitmap,int pos,int order)491 bitmap_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 */
510 static inline void
bitmap_release_region(unsigned long * bitmap,int pos,int order)511 bitmap_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_ */
523