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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
cafe5635 KO |
2 | |
3 | #ifndef _BCACHE_UTIL_H | |
4 | #define _BCACHE_UTIL_H | |
5 | ||
9a02b7ee | 6 | #include <linux/blkdev.h> |
8c8d2d96 | 7 | #include <linux/closure.h> |
cafe5635 KO |
8 | #include <linux/errno.h> |
9 | #include <linux/kernel.h> | |
e6017571 | 10 | #include <linux/sched/clock.h> |
cafe5635 KO |
11 | #include <linux/llist.h> |
12 | #include <linux/ratelimit.h> | |
13 | #include <linux/vmalloc.h> | |
14 | #include <linux/workqueue.h> | |
d2359963 | 15 | #include <linux/crc64.h> |
cafe5635 | 16 | |
cafe5635 KO |
17 | struct closure; |
18 | ||
280481d0 | 19 | #ifdef CONFIG_BCACHE_DEBUG |
cafe5635 | 20 | |
dc9d98d6 | 21 | #define EBUG_ON(cond) BUG_ON(cond) |
cafe5635 KO |
22 | #define atomic_dec_bug(v) BUG_ON(atomic_dec_return(v) < 0) |
23 | #define atomic_inc_bug(v, i) BUG_ON(atomic_inc_return(v) <= i) | |
24 | ||
280481d0 | 25 | #else /* DEBUG */ |
cafe5635 | 26 | |
be3bacec | 27 | #define EBUG_ON(cond) do { if (cond) do {} while (0); } while (0) |
cafe5635 KO |
28 | #define atomic_dec_bug(v) atomic_dec(v) |
29 | #define atomic_inc_bug(v, i) atomic_inc(v) | |
30 | ||
31 | #endif | |
32 | ||
cafe5635 KO |
33 | #define DECLARE_HEAP(type, name) \ |
34 | struct { \ | |
35 | size_t size, used; \ | |
36 | type *data; \ | |
37 | } name | |
38 | ||
39 | #define init_heap(heap, _size, gfp) \ | |
40 | ({ \ | |
41 | size_t _bytes; \ | |
42 | (heap)->used = 0; \ | |
43 | (heap)->size = (_size); \ | |
44 | _bytes = (heap)->size * sizeof(*(heap)->data); \ | |
752ade68 | 45 | (heap)->data = kvmalloc(_bytes, (gfp) & GFP_KERNEL); \ |
cafe5635 KO |
46 | (heap)->data; \ |
47 | }) | |
48 | ||
49 | #define free_heap(heap) \ | |
50 | do { \ | |
958b4338 | 51 | kvfree((heap)->data); \ |
cafe5635 KO |
52 | (heap)->data = NULL; \ |
53 | } while (0) | |
54 | ||
55 | #define heap_swap(h, i, j) swap((h)->data[i], (h)->data[j]) | |
56 | ||
57 | #define heap_sift(h, i, cmp) \ | |
58 | do { \ | |
59 | size_t _r, _j = i; \ | |
60 | \ | |
61 | for (; _j * 2 + 1 < (h)->used; _j = _r) { \ | |
62 | _r = _j * 2 + 1; \ | |
63 | if (_r + 1 < (h)->used && \ | |
64 | cmp((h)->data[_r], (h)->data[_r + 1])) \ | |
65 | _r++; \ | |
66 | \ | |
67 | if (cmp((h)->data[_r], (h)->data[_j])) \ | |
68 | break; \ | |
69 | heap_swap(h, _r, _j); \ | |
70 | } \ | |
71 | } while (0) | |
72 | ||
73 | #define heap_sift_down(h, i, cmp) \ | |
74 | do { \ | |
75 | while (i) { \ | |
76 | size_t p = (i - 1) / 2; \ | |
77 | if (cmp((h)->data[i], (h)->data[p])) \ | |
78 | break; \ | |
79 | heap_swap(h, i, p); \ | |
80 | i = p; \ | |
81 | } \ | |
82 | } while (0) | |
83 | ||
84 | #define heap_add(h, d, cmp) \ | |
85 | ({ \ | |
86 | bool _r = !heap_full(h); \ | |
87 | if (_r) { \ | |
88 | size_t _i = (h)->used++; \ | |
89 | (h)->data[_i] = d; \ | |
90 | \ | |
91 | heap_sift_down(h, _i, cmp); \ | |
92 | heap_sift(h, _i, cmp); \ | |
93 | } \ | |
94 | _r; \ | |
95 | }) | |
96 | ||
97 | #define heap_pop(h, d, cmp) \ | |
98 | ({ \ | |
99 | bool _r = (h)->used; \ | |
100 | if (_r) { \ | |
101 | (d) = (h)->data[0]; \ | |
102 | (h)->used--; \ | |
103 | heap_swap(h, 0, (h)->used); \ | |
104 | heap_sift(h, 0, cmp); \ | |
105 | } \ | |
106 | _r; \ | |
107 | }) | |
108 | ||
97d11a66 | 109 | #define heap_peek(h) ((h)->used ? (h)->data[0] : NULL) |
cafe5635 KO |
110 | |
111 | #define heap_full(h) ((h)->used == (h)->size) | |
112 | ||
113 | #define DECLARE_FIFO(type, name) \ | |
114 | struct { \ | |
115 | size_t front, back, size, mask; \ | |
116 | type *data; \ | |
117 | } name | |
118 | ||
119 | #define fifo_for_each(c, fifo, iter) \ | |
120 | for (iter = (fifo)->front; \ | |
121 | c = (fifo)->data[iter], iter != (fifo)->back; \ | |
122 | iter = (iter + 1) & (fifo)->mask) | |
123 | ||
124 | #define __init_fifo(fifo, gfp) \ | |
125 | ({ \ | |
126 | size_t _allocated_size, _bytes; \ | |
127 | BUG_ON(!(fifo)->size); \ | |
128 | \ | |
129 | _allocated_size = roundup_pow_of_two((fifo)->size + 1); \ | |
130 | _bytes = _allocated_size * sizeof(*(fifo)->data); \ | |
131 | \ | |
132 | (fifo)->mask = _allocated_size - 1; \ | |
133 | (fifo)->front = (fifo)->back = 0; \ | |
cafe5635 | 134 | \ |
752ade68 | 135 | (fifo)->data = kvmalloc(_bytes, (gfp) & GFP_KERNEL); \ |
cafe5635 KO |
136 | (fifo)->data; \ |
137 | }) | |
138 | ||
139 | #define init_fifo_exact(fifo, _size, gfp) \ | |
140 | ({ \ | |
141 | (fifo)->size = (_size); \ | |
142 | __init_fifo(fifo, gfp); \ | |
143 | }) | |
144 | ||
145 | #define init_fifo(fifo, _size, gfp) \ | |
146 | ({ \ | |
147 | (fifo)->size = (_size); \ | |
148 | if ((fifo)->size > 4) \ | |
149 | (fifo)->size = roundup_pow_of_two((fifo)->size) - 1; \ | |
150 | __init_fifo(fifo, gfp); \ | |
151 | }) | |
152 | ||
153 | #define free_fifo(fifo) \ | |
154 | do { \ | |
958b4338 | 155 | kvfree((fifo)->data); \ |
cafe5635 KO |
156 | (fifo)->data = NULL; \ |
157 | } while (0) | |
158 | ||
159 | #define fifo_used(fifo) (((fifo)->back - (fifo)->front) & (fifo)->mask) | |
160 | #define fifo_free(fifo) ((fifo)->size - fifo_used(fifo)) | |
161 | ||
162 | #define fifo_empty(fifo) (!fifo_used(fifo)) | |
163 | #define fifo_full(fifo) (!fifo_free(fifo)) | |
164 | ||
165 | #define fifo_front(fifo) ((fifo)->data[(fifo)->front]) | |
166 | #define fifo_back(fifo) \ | |
167 | ((fifo)->data[((fifo)->back - 1) & (fifo)->mask]) | |
168 | ||
169 | #define fifo_idx(fifo, p) (((p) - &fifo_front(fifo)) & (fifo)->mask) | |
170 | ||
171 | #define fifo_push_back(fifo, i) \ | |
172 | ({ \ | |
173 | bool _r = !fifo_full((fifo)); \ | |
174 | if (_r) { \ | |
175 | (fifo)->data[(fifo)->back++] = (i); \ | |
176 | (fifo)->back &= (fifo)->mask; \ | |
177 | } \ | |
178 | _r; \ | |
179 | }) | |
180 | ||
181 | #define fifo_pop_front(fifo, i) \ | |
182 | ({ \ | |
183 | bool _r = !fifo_empty((fifo)); \ | |
184 | if (_r) { \ | |
185 | (i) = (fifo)->data[(fifo)->front++]; \ | |
186 | (fifo)->front &= (fifo)->mask; \ | |
187 | } \ | |
188 | _r; \ | |
189 | }) | |
190 | ||
191 | #define fifo_push_front(fifo, i) \ | |
192 | ({ \ | |
193 | bool _r = !fifo_full((fifo)); \ | |
194 | if (_r) { \ | |
195 | --(fifo)->front; \ | |
196 | (fifo)->front &= (fifo)->mask; \ | |
197 | (fifo)->data[(fifo)->front] = (i); \ | |
198 | } \ | |
199 | _r; \ | |
200 | }) | |
201 | ||
202 | #define fifo_pop_back(fifo, i) \ | |
203 | ({ \ | |
204 | bool _r = !fifo_empty((fifo)); \ | |
205 | if (_r) { \ | |
206 | --(fifo)->back; \ | |
207 | (fifo)->back &= (fifo)->mask; \ | |
208 | (i) = (fifo)->data[(fifo)->back] \ | |
209 | } \ | |
210 | _r; \ | |
211 | }) | |
212 | ||
213 | #define fifo_push(fifo, i) fifo_push_back(fifo, (i)) | |
214 | #define fifo_pop(fifo, i) fifo_pop_front(fifo, (i)) | |
215 | ||
216 | #define fifo_swap(l, r) \ | |
217 | do { \ | |
218 | swap((l)->front, (r)->front); \ | |
219 | swap((l)->back, (r)->back); \ | |
220 | swap((l)->size, (r)->size); \ | |
221 | swap((l)->mask, (r)->mask); \ | |
222 | swap((l)->data, (r)->data); \ | |
223 | } while (0) | |
224 | ||
225 | #define fifo_move(dest, src) \ | |
226 | do { \ | |
227 | typeof(*((dest)->data)) _t; \ | |
228 | while (!fifo_full(dest) && \ | |
229 | fifo_pop(src, _t)) \ | |
230 | fifo_push(dest, _t); \ | |
231 | } while (0) | |
232 | ||
233 | /* | |
234 | * Simple array based allocator - preallocates a number of elements and you can | |
235 | * never allocate more than that, also has no locking. | |
236 | * | |
237 | * Handy because if you know you only need a fixed number of elements you don't | |
238 | * have to worry about memory allocation failure, and sometimes a mempool isn't | |
239 | * what you want. | |
240 | * | |
241 | * We treat the free elements as entries in a singly linked list, and the | |
242 | * freelist as a stack - allocating and freeing push and pop off the freelist. | |
243 | */ | |
244 | ||
245 | #define DECLARE_ARRAY_ALLOCATOR(type, name, size) \ | |
246 | struct { \ | |
247 | type *freelist; \ | |
248 | type data[size]; \ | |
249 | } name | |
250 | ||
251 | #define array_alloc(array) \ | |
252 | ({ \ | |
253 | typeof((array)->freelist) _ret = (array)->freelist; \ | |
254 | \ | |
255 | if (_ret) \ | |
256 | (array)->freelist = *((typeof((array)->freelist) *) _ret);\ | |
257 | \ | |
258 | _ret; \ | |
259 | }) | |
260 | ||
261 | #define array_free(array, ptr) \ | |
262 | do { \ | |
263 | typeof((array)->freelist) _ptr = ptr; \ | |
264 | \ | |
265 | *((typeof((array)->freelist) *) _ptr) = (array)->freelist; \ | |
266 | (array)->freelist = _ptr; \ | |
267 | } while (0) | |
268 | ||
269 | #define array_allocator_init(array) \ | |
270 | do { \ | |
271 | typeof((array)->freelist) _i; \ | |
272 | \ | |
273 | BUILD_BUG_ON(sizeof((array)->data[0]) < sizeof(void *)); \ | |
274 | (array)->freelist = NULL; \ | |
275 | \ | |
276 | for (_i = (array)->data; \ | |
277 | _i < (array)->data + ARRAY_SIZE((array)->data); \ | |
278 | _i++) \ | |
279 | array_free(array, _i); \ | |
280 | } while (0) | |
281 | ||
282 | #define array_freelist_empty(array) ((array)->freelist == NULL) | |
283 | ||
284 | #define ANYSINT_MAX(t) \ | |
285 | ((((t) 1 << (sizeof(t) * 8 - 2)) - (t) 1) * (t) 2 + (t) 1) | |
286 | ||
fc2d5988 CL |
287 | int bch_strtoint_h(const char *cp, int *res); |
288 | int bch_strtouint_h(const char *cp, unsigned int *res); | |
289 | int bch_strtoll_h(const char *cp, long long *res); | |
290 | int bch_strtoull_h(const char *cp, unsigned long long *res); | |
cafe5635 | 291 | |
169ef1cf | 292 | static inline int bch_strtol_h(const char *cp, long *res) |
cafe5635 KO |
293 | { |
294 | #if BITS_PER_LONG == 32 | |
169ef1cf | 295 | return bch_strtoint_h(cp, (int *) res); |
cafe5635 | 296 | #else |
169ef1cf | 297 | return bch_strtoll_h(cp, (long long *) res); |
cafe5635 KO |
298 | #endif |
299 | } | |
300 | ||
169ef1cf | 301 | static inline int bch_strtoul_h(const char *cp, long *res) |
cafe5635 KO |
302 | { |
303 | #if BITS_PER_LONG == 32 | |
169ef1cf | 304 | return bch_strtouint_h(cp, (unsigned int *) res); |
cafe5635 | 305 | #else |
169ef1cf | 306 | return bch_strtoull_h(cp, (unsigned long long *) res); |
cafe5635 KO |
307 | #endif |
308 | } | |
309 | ||
310 | #define strtoi_h(cp, res) \ | |
311 | (__builtin_types_compatible_p(typeof(*res), int) \ | |
169ef1cf | 312 | ? bch_strtoint_h(cp, (void *) res) \ |
cafe5635 | 313 | : __builtin_types_compatible_p(typeof(*res), long) \ |
169ef1cf | 314 | ? bch_strtol_h(cp, (void *) res) \ |
cafe5635 | 315 | : __builtin_types_compatible_p(typeof(*res), long long) \ |
169ef1cf | 316 | ? bch_strtoll_h(cp, (void *) res) \ |
cafe5635 | 317 | : __builtin_types_compatible_p(typeof(*res), unsigned int) \ |
169ef1cf | 318 | ? bch_strtouint_h(cp, (void *) res) \ |
cafe5635 | 319 | : __builtin_types_compatible_p(typeof(*res), unsigned long) \ |
169ef1cf | 320 | ? bch_strtoul_h(cp, (void *) res) \ |
cafe5635 | 321 | : __builtin_types_compatible_p(typeof(*res), unsigned long long)\ |
169ef1cf | 322 | ? bch_strtoull_h(cp, (void *) res) : -EINVAL) |
cafe5635 KO |
323 | |
324 | #define strtoul_safe(cp, var) \ | |
325 | ({ \ | |
326 | unsigned long _v; \ | |
327 | int _r = kstrtoul(cp, 10, &_v); \ | |
328 | if (!_r) \ | |
329 | var = _v; \ | |
330 | _r; \ | |
331 | }) | |
332 | ||
333 | #define strtoul_safe_clamp(cp, var, min, max) \ | |
334 | ({ \ | |
335 | unsigned long _v; \ | |
336 | int _r = kstrtoul(cp, 10, &_v); \ | |
337 | if (!_r) \ | |
338 | var = clamp_t(typeof(var), _v, min, max); \ | |
339 | _r; \ | |
340 | }) | |
341 | ||
169ef1cf | 342 | ssize_t bch_hprint(char *buf, int64_t v); |
cafe5635 | 343 | |
169ef1cf KO |
344 | bool bch_is_zero(const char *p, size_t n); |
345 | int bch_parse_uuid(const char *s, char *uuid); | |
cafe5635 | 346 | |
cafe5635 | 347 | struct time_stats { |
65d22e91 | 348 | spinlock_t lock; |
cafe5635 KO |
349 | /* |
350 | * all fields are in nanoseconds, averages are ewmas stored left shifted | |
351 | * by 8 | |
352 | */ | |
353 | uint64_t max_duration; | |
354 | uint64_t average_duration; | |
355 | uint64_t average_frequency; | |
356 | uint64_t last; | |
357 | }; | |
358 | ||
169ef1cf | 359 | void bch_time_stats_update(struct time_stats *stats, uint64_t time); |
cafe5635 | 360 | |
6f10f7d1 | 361 | static inline unsigned int local_clock_us(void) |
9a02b7ee KO |
362 | { |
363 | return local_clock() >> 10; | |
364 | } | |
365 | ||
cafe5635 KO |
366 | #define NSEC_PER_ns 1L |
367 | #define NSEC_PER_us NSEC_PER_USEC | |
368 | #define NSEC_PER_ms NSEC_PER_MSEC | |
369 | #define NSEC_PER_sec NSEC_PER_SEC | |
370 | ||
371 | #define __print_time_stat(stats, name, stat, units) \ | |
372 | sysfs_print(name ## _ ## stat ## _ ## units, \ | |
373 | div_u64((stats)->stat >> 8, NSEC_PER_ ## units)) | |
374 | ||
375 | #define sysfs_print_time_stats(stats, name, \ | |
376 | frequency_units, \ | |
377 | duration_units) \ | |
378 | do { \ | |
379 | __print_time_stat(stats, name, \ | |
380 | average_frequency, frequency_units); \ | |
381 | __print_time_stat(stats, name, \ | |
382 | average_duration, duration_units); \ | |
5b25abad | 383 | sysfs_print(name ## _ ##max_duration ## _ ## duration_units, \ |
b0d30981 CL |
384 | div_u64((stats)->max_duration, \ |
385 | NSEC_PER_ ## duration_units)); \ | |
cafe5635 KO |
386 | \ |
387 | sysfs_print(name ## _last_ ## frequency_units, (stats)->last \ | |
388 | ? div_s64(local_clock() - (stats)->last, \ | |
389 | NSEC_PER_ ## frequency_units) \ | |
390 | : -1LL); \ | |
391 | } while (0) | |
392 | ||
393 | #define sysfs_time_stats_attribute(name, \ | |
394 | frequency_units, \ | |
395 | duration_units) \ | |
396 | read_attribute(name ## _average_frequency_ ## frequency_units); \ | |
397 | read_attribute(name ## _average_duration_ ## duration_units); \ | |
398 | read_attribute(name ## _max_duration_ ## duration_units); \ | |
399 | read_attribute(name ## _last_ ## frequency_units) | |
400 | ||
401 | #define sysfs_time_stats_attribute_list(name, \ | |
402 | frequency_units, \ | |
403 | duration_units) \ | |
404 | &sysfs_ ## name ## _average_frequency_ ## frequency_units, \ | |
405 | &sysfs_ ## name ## _average_duration_ ## duration_units, \ | |
406 | &sysfs_ ## name ## _max_duration_ ## duration_units, \ | |
407 | &sysfs_ ## name ## _last_ ## frequency_units, | |
408 | ||
409 | #define ewma_add(ewma, val, weight, factor) \ | |
410 | ({ \ | |
411 | (ewma) *= (weight) - 1; \ | |
412 | (ewma) += (val) << factor; \ | |
413 | (ewma) /= (weight); \ | |
414 | (ewma) >> factor; \ | |
415 | }) | |
416 | ||
c2a4f318 KO |
417 | struct bch_ratelimit { |
418 | /* Next time we want to do some work, in nanoseconds */ | |
cafe5635 | 419 | uint64_t next; |
c2a4f318 KO |
420 | |
421 | /* | |
e41166c5 | 422 | * Rate at which we want to do work, in units per second |
c2a4f318 KO |
423 | * The units here correspond to the units passed to bch_next_delay() |
424 | */ | |
ea8c5356 | 425 | atomic_long_t rate; |
cafe5635 KO |
426 | }; |
427 | ||
c2a4f318 | 428 | static inline void bch_ratelimit_reset(struct bch_ratelimit *d) |
cafe5635 KO |
429 | { |
430 | d->next = local_clock(); | |
431 | } | |
432 | ||
c2a4f318 | 433 | uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done); |
cafe5635 KO |
434 | |
435 | #define __DIV_SAFE(n, d, zero) \ | |
436 | ({ \ | |
437 | typeof(n) _n = (n); \ | |
438 | typeof(d) _d = (d); \ | |
439 | _d ? _n / _d : zero; \ | |
440 | }) | |
441 | ||
442 | #define DIV_SAFE(n, d) __DIV_SAFE(n, d, 0) | |
443 | ||
444 | #define container_of_or_null(ptr, type, member) \ | |
445 | ({ \ | |
446 | typeof(ptr) _ptr = ptr; \ | |
447 | _ptr ? container_of(_ptr, type, member) : NULL; \ | |
448 | }) | |
449 | ||
450 | #define RB_INSERT(root, new, member, cmp) \ | |
451 | ({ \ | |
452 | __label__ dup; \ | |
453 | struct rb_node **n = &(root)->rb_node, *parent = NULL; \ | |
454 | typeof(new) this; \ | |
455 | int res, ret = -1; \ | |
456 | \ | |
457 | while (*n) { \ | |
458 | parent = *n; \ | |
459 | this = container_of(*n, typeof(*(new)), member); \ | |
460 | res = cmp(new, this); \ | |
461 | if (!res) \ | |
462 | goto dup; \ | |
463 | n = res < 0 \ | |
464 | ? &(*n)->rb_left \ | |
465 | : &(*n)->rb_right; \ | |
466 | } \ | |
467 | \ | |
468 | rb_link_node(&(new)->member, parent, n); \ | |
469 | rb_insert_color(&(new)->member, root); \ | |
470 | ret = 0; \ | |
471 | dup: \ | |
472 | ret; \ | |
473 | }) | |
474 | ||
475 | #define RB_SEARCH(root, search, member, cmp) \ | |
476 | ({ \ | |
477 | struct rb_node *n = (root)->rb_node; \ | |
478 | typeof(&(search)) this, ret = NULL; \ | |
479 | int res; \ | |
480 | \ | |
481 | while (n) { \ | |
482 | this = container_of(n, typeof(search), member); \ | |
483 | res = cmp(&(search), this); \ | |
484 | if (!res) { \ | |
485 | ret = this; \ | |
486 | break; \ | |
487 | } \ | |
488 | n = res < 0 \ | |
489 | ? n->rb_left \ | |
490 | : n->rb_right; \ | |
491 | } \ | |
492 | ret; \ | |
493 | }) | |
494 | ||
495 | #define RB_GREATER(root, search, member, cmp) \ | |
496 | ({ \ | |
497 | struct rb_node *n = (root)->rb_node; \ | |
498 | typeof(&(search)) this, ret = NULL; \ | |
499 | int res; \ | |
500 | \ | |
501 | while (n) { \ | |
502 | this = container_of(n, typeof(search), member); \ | |
503 | res = cmp(&(search), this); \ | |
504 | if (res < 0) { \ | |
505 | ret = this; \ | |
506 | n = n->rb_left; \ | |
507 | } else \ | |
508 | n = n->rb_right; \ | |
509 | } \ | |
510 | ret; \ | |
511 | }) | |
512 | ||
513 | #define RB_FIRST(root, type, member) \ | |
514 | container_of_or_null(rb_first(root), type, member) | |
515 | ||
516 | #define RB_LAST(root, type, member) \ | |
517 | container_of_or_null(rb_last(root), type, member) | |
518 | ||
519 | #define RB_NEXT(ptr, member) \ | |
520 | container_of_or_null(rb_next(&(ptr)->member), typeof(*ptr), member) | |
521 | ||
522 | #define RB_PREV(ptr, member) \ | |
523 | container_of_or_null(rb_prev(&(ptr)->member), typeof(*ptr), member) | |
524 | ||
d2359963 CL |
525 | static inline uint64_t bch_crc64(const void *p, size_t len) |
526 | { | |
527 | uint64_t crc = 0xffffffffffffffffULL; | |
528 | ||
529 | crc = crc64_be(crc, p, len); | |
530 | return crc ^ 0xffffffffffffffffULL; | |
531 | } | |
532 | ||
3a394727 GS |
533 | /* |
534 | * A stepwise-linear pseudo-exponential. This returns 1 << (x >> | |
535 | * frac_bits), with the less-significant bits filled in by linear | |
536 | * interpolation. | |
537 | * | |
538 | * This can also be interpreted as a floating-point number format, | |
539 | * where the low frac_bits are the mantissa (with implicit leading | |
540 | * 1 bit), and the more significant bits are the exponent. | |
541 | * The return value is 1.mantissa * 2^exponent. | |
542 | * | |
543 | * The way this is used, fract_bits is 6 and the largest possible | |
544 | * input is CONGESTED_MAX-1 = 1023 (exponent 16, mantissa 0x1.fc), | |
545 | * so the maximum output is 0x1fc00. | |
546 | */ | |
6f10f7d1 CL |
547 | static inline unsigned int fract_exp_two(unsigned int x, |
548 | unsigned int fract_bits) | |
cafe5635 | 549 | { |
3a394727 | 550 | unsigned int mantissa = 1 << fract_bits; /* Implicit bit */ |
cafe5635 | 551 | |
3a394727 GS |
552 | mantissa += x & (mantissa - 1); |
553 | x >>= fract_bits; /* The exponent */ | |
554 | /* Largest intermediate value 0x7f0000 */ | |
555 | return mantissa << x >> fract_bits; | |
cafe5635 KO |
556 | } |
557 | ||
169ef1cf | 558 | void bch_bio_map(struct bio *bio, void *base); |
25d8be77 | 559 | int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask); |
cafe5635 | 560 | |
cafe5635 | 561 | #endif /* _BCACHE_UTIL_H */ |