diff options
Diffstat (limited to 'include/linux/log2.h')
-rw-r--r-- | include/linux/log2.h | 26 |
1 files changed, 14 insertions, 12 deletions
diff --git a/include/linux/log2.h b/include/linux/log2.h index fd7ff3d91e6a..c373295f359f 100644 --- a/include/linux/log2.h +++ b/include/linux/log2.h | |||
@@ -16,12 +16,6 @@ | |||
16 | #include <linux/bitops.h> | 16 | #include <linux/bitops.h> |
17 | 17 | ||
18 | /* | 18 | /* |
19 | * deal with unrepresentable constant logarithms | ||
20 | */ | ||
21 | extern __attribute__((const, noreturn)) | ||
22 | int ____ilog2_NaN(void); | ||
23 | |||
24 | /* | ||
25 | * non-constant log of base 2 calculators | 19 | * non-constant log of base 2 calculators |
26 | * - the arch may override these in asm/bitops.h if they can be implemented | 20 | * - the arch may override these in asm/bitops.h if they can be implemented |
27 | * more efficiently than using fls() and fls64() | 21 | * more efficiently than using fls() and fls64() |
@@ -85,7 +79,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n) | |||
85 | #define ilog2(n) \ | 79 | #define ilog2(n) \ |
86 | ( \ | 80 | ( \ |
87 | __builtin_constant_p(n) ? ( \ | 81 | __builtin_constant_p(n) ? ( \ |
88 | (n) < 1 ? ____ilog2_NaN() : \ | 82 | (n) < 2 ? 0 : \ |
89 | (n) & (1ULL << 63) ? 63 : \ | 83 | (n) & (1ULL << 63) ? 63 : \ |
90 | (n) & (1ULL << 62) ? 62 : \ | 84 | (n) & (1ULL << 62) ? 62 : \ |
91 | (n) & (1ULL << 61) ? 61 : \ | 85 | (n) & (1ULL << 61) ? 61 : \ |
@@ -148,10 +142,7 @@ unsigned long __rounddown_pow_of_two(unsigned long n) | |||
148 | (n) & (1ULL << 4) ? 4 : \ | 142 | (n) & (1ULL << 4) ? 4 : \ |
149 | (n) & (1ULL << 3) ? 3 : \ | 143 | (n) & (1ULL << 3) ? 3 : \ |
150 | (n) & (1ULL << 2) ? 2 : \ | 144 | (n) & (1ULL << 2) ? 2 : \ |
151 | (n) & (1ULL << 1) ? 1 : \ | 145 | 1 ) : \ |
152 | (n) & (1ULL << 0) ? 0 : \ | ||
153 | ____ilog2_NaN() \ | ||
154 | ) : \ | ||
155 | (sizeof(n) <= 4) ? \ | 146 | (sizeof(n) <= 4) ? \ |
156 | __ilog2_u32(n) : \ | 147 | __ilog2_u32(n) : \ |
157 | __ilog2_u64(n) \ | 148 | __ilog2_u64(n) \ |
@@ -203,6 +194,17 @@ unsigned long __rounddown_pow_of_two(unsigned long n) | |||
203 | * ... and so on. | 194 | * ... and so on. |
204 | */ | 195 | */ |
205 | 196 | ||
206 | #define order_base_2(n) ilog2(roundup_pow_of_two(n)) | 197 | static inline __attribute_const__ |
198 | int __order_base_2(unsigned long n) | ||
199 | { | ||
200 | return n > 1 ? ilog2(n - 1) + 1 : 0; | ||
201 | } | ||
207 | 202 | ||
203 | #define order_base_2(n) \ | ||
204 | ( \ | ||
205 | __builtin_constant_p(n) ? ( \ | ||
206 | ((n) == 0 || (n) == 1) ? 0 : \ | ||
207 | ilog2((n) - 1) + 1) : \ | ||
208 | __order_base_2(n) \ | ||
209 | ) | ||
208 | #endif /* _LINUX_LOG2_H */ | 210 | #endif /* _LINUX_LOG2_H */ |