+++ /dev/null
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/* Integer base 2 logarithm calculation
- *
- * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
- * Written by David Howells (dhowells@redhat.com)
- */
-
-#ifndef _LINUX_LOG2_H
-#define _LINUX_LOG2_H
-
-#include <linux/types.h>
-#include <linux/bitops.h>
-
-/*
- * non-constant log of base 2 calculators
- * - the arch may override these in asm/bitops.h if they can be implemented
- * more efficiently than using fls() and fls64()
- * - the arch is not required to handle n==0 if implementing the fallback
- */
-#ifndef CONFIG_ARCH_HAS_ILOG2_U32
-static inline __attribute__((const))
-int __ilog2_u32(u32 n)
-{
- return fls(n) - 1;
-}
-#endif
-
-#ifndef CONFIG_ARCH_HAS_ILOG2_U64
-static inline __attribute__((const))
-int __ilog2_u64(u64 n)
-{
- return fls64(n) - 1;
-}
-#endif
-
-/**
- * is_power_of_2() - check if a value is a power of two
- * @n: the value to check
- *
- * Determine whether some value is a power of two, where zero is
- * *not* considered a power of two.
- * Return: true if @n is a power of 2, otherwise false.
- */
-static inline __attribute__((const))
-bool is_power_of_2(unsigned long n)
-{
- return (n != 0 && ((n & (n - 1)) == 0));
-}
-
-/**
- * __roundup_pow_of_two() - round up to nearest power of two
- * @n: value to round up
- */
-static inline __attribute__((const))
-unsigned long __roundup_pow_of_two(unsigned long n)
-{
- return 1UL << fls_long(n - 1);
-}
-
-/**
- * __rounddown_pow_of_two() - round down to nearest power of two
- * @n: value to round down
- */
-static inline __attribute__((const))
-unsigned long __rounddown_pow_of_two(unsigned long n)
-{
- return 1UL << (fls_long(n) - 1);
-}
-
-/**
- * const_ilog2 - log base 2 of 32-bit or a 64-bit constant unsigned value
- * @n: parameter
- *
- * Use this where sparse expects a true constant expression, e.g. for array
- * indices.
- */
-#define const_ilog2(n) \
-( \
- __builtin_constant_p(n) ? ( \
- (n) < 2 ? 0 : \
- (n) & (1ULL << 63) ? 63 : \
- (n) & (1ULL << 62) ? 62 : \
- (n) & (1ULL << 61) ? 61 : \
- (n) & (1ULL << 60) ? 60 : \
- (n) & (1ULL << 59) ? 59 : \
- (n) & (1ULL << 58) ? 58 : \
- (n) & (1ULL << 57) ? 57 : \
- (n) & (1ULL << 56) ? 56 : \
- (n) & (1ULL << 55) ? 55 : \
- (n) & (1ULL << 54) ? 54 : \
- (n) & (1ULL << 53) ? 53 : \
- (n) & (1ULL << 52) ? 52 : \
- (n) & (1ULL << 51) ? 51 : \
- (n) & (1ULL << 50) ? 50 : \
- (n) & (1ULL << 49) ? 49 : \
- (n) & (1ULL << 48) ? 48 : \
- (n) & (1ULL << 47) ? 47 : \
- (n) & (1ULL << 46) ? 46 : \
- (n) & (1ULL << 45) ? 45 : \
- (n) & (1ULL << 44) ? 44 : \
- (n) & (1ULL << 43) ? 43 : \
- (n) & (1ULL << 42) ? 42 : \
- (n) & (1ULL << 41) ? 41 : \
- (n) & (1ULL << 40) ? 40 : \
- (n) & (1ULL << 39) ? 39 : \
- (n) & (1ULL << 38) ? 38 : \
- (n) & (1ULL << 37) ? 37 : \
- (n) & (1ULL << 36) ? 36 : \
- (n) & (1ULL << 35) ? 35 : \
- (n) & (1ULL << 34) ? 34 : \
- (n) & (1ULL << 33) ? 33 : \
- (n) & (1ULL << 32) ? 32 : \
- (n) & (1ULL << 31) ? 31 : \
- (n) & (1ULL << 30) ? 30 : \
- (n) & (1ULL << 29) ? 29 : \
- (n) & (1ULL << 28) ? 28 : \
- (n) & (1ULL << 27) ? 27 : \
- (n) & (1ULL << 26) ? 26 : \
- (n) & (1ULL << 25) ? 25 : \
- (n) & (1ULL << 24) ? 24 : \
- (n) & (1ULL << 23) ? 23 : \
- (n) & (1ULL << 22) ? 22 : \
- (n) & (1ULL << 21) ? 21 : \
- (n) & (1ULL << 20) ? 20 : \
- (n) & (1ULL << 19) ? 19 : \
- (n) & (1ULL << 18) ? 18 : \
- (n) & (1ULL << 17) ? 17 : \
- (n) & (1ULL << 16) ? 16 : \
- (n) & (1ULL << 15) ? 15 : \
- (n) & (1ULL << 14) ? 14 : \
- (n) & (1ULL << 13) ? 13 : \
- (n) & (1ULL << 12) ? 12 : \
- (n) & (1ULL << 11) ? 11 : \
- (n) & (1ULL << 10) ? 10 : \
- (n) & (1ULL << 9) ? 9 : \
- (n) & (1ULL << 8) ? 8 : \
- (n) & (1ULL << 7) ? 7 : \
- (n) & (1ULL << 6) ? 6 : \
- (n) & (1ULL << 5) ? 5 : \
- (n) & (1ULL << 4) ? 4 : \
- (n) & (1ULL << 3) ? 3 : \
- (n) & (1ULL << 2) ? 2 : \
- 1) : \
- -1)
-
-/**
- * ilog2 - log base 2 of 32-bit or a 64-bit unsigned value
- * @n: parameter
- *
- * constant-capable log of base 2 calculation
- * - this can be used to initialise global variables from constant data, hence
- * the massive ternary operator construction
- *
- * selects the appropriately-sized optimised version depending on sizeof(n)
- */
-#define ilog2(n) \
-( \
- __builtin_constant_p(n) ? \
- const_ilog2(n) : \
- (sizeof(n) <= 4) ? \
- __ilog2_u32(n) : \
- __ilog2_u64(n) \
- )
-
-/**
- * roundup_pow_of_two - round the given value up to nearest power of two
- * @n: parameter
- *
- * round the given value up to the nearest power of two
- * - the result is undefined when n == 0
- * - this can be used to initialise global variables from constant data
- */
-#define roundup_pow_of_two(n) \
-( \
- __builtin_constant_p(n) ? ( \
- (n == 1) ? 1 : \
- (1UL << (ilog2((n) - 1) + 1)) \
- ) : \
- __roundup_pow_of_two(n) \
- )
-
-/**
- * rounddown_pow_of_two - round the given value down to nearest power of two
- * @n: parameter
- *
- * round the given value down to the nearest power of two
- * - the result is undefined when n == 0
- * - this can be used to initialise global variables from constant data
- */
-#define rounddown_pow_of_two(n) \
-( \
- __builtin_constant_p(n) ? ( \
- (1UL << ilog2(n))) : \
- __rounddown_pow_of_two(n) \
- )
-
-static inline __attribute_const__
-int __order_base_2(unsigned long n)
-{
- return n > 1 ? ilog2(n - 1) + 1 : 0;
-}
-
-/**
- * order_base_2 - calculate the (rounded up) base 2 order of the argument
- * @n: parameter
- *
- * The first few values calculated by this routine:
- * ob2(0) = 0
- * ob2(1) = 0
- * ob2(2) = 1
- * ob2(3) = 2
- * ob2(4) = 2
- * ob2(5) = 3
- * ... and so on.
- */
-#define order_base_2(n) \
-( \
- __builtin_constant_p(n) ? ( \
- ((n) == 0 || (n) == 1) ? 0 : \
- ilog2((n) - 1) + 1) : \
- __order_base_2(n) \
-)
-
-static inline __attribute__((const))
-int __bits_per(unsigned long n)
-{
- if (n < 2)
- return 1;
- if (is_power_of_2(n))
- return order_base_2(n) + 1;
- return order_base_2(n);
-}
-
-/**
- * bits_per - calculate the number of bits required for the argument
- * @n: parameter
- *
- * This is constant-capable and can be used for compile time
- * initializations, e.g bitfields.
- *
- * The first few values calculated by this routine:
- * bf(0) = 1
- * bf(1) = 1
- * bf(2) = 2
- * bf(3) = 2
- * bf(4) = 3
- * ... and so on.
- */
-#define bits_per(n) \
-( \
- __builtin_constant_p(n) ? ( \
- ((n) == 0 || (n) == 1) \
- ? 1 : ilog2(n) + 1 \
- ) : \
- __bits_per(n) \
-)
-
-/**
- * get_order - Determine the allocation order of a memory size
- * @size: The size for which to get the order
- *
- * Determine the allocation order of a particular sized block of memory. This
- * is on a logarithmic scale, where:
- *
- * 0 -> 2^0 * PAGE_SIZE and below
- * 1 -> 2^1 * PAGE_SIZE to 2^0 * PAGE_SIZE + 1
- * 2 -> 2^2 * PAGE_SIZE to 2^1 * PAGE_SIZE + 1
- * 3 -> 2^3 * PAGE_SIZE to 2^2 * PAGE_SIZE + 1
- * 4 -> 2^4 * PAGE_SIZE to 2^3 * PAGE_SIZE + 1
- * ...
- *
- * The order returned is used to find the smallest allocation granule required
- * to hold an object of the specified size.
- *
- * The result is undefined if the size is 0.
- */
-static inline __attribute_const__ int get_order(unsigned long size)
-{
- if (__builtin_constant_p(size)) {
- if (!size)
- return BITS_PER_LONG - PAGE_SHIFT;
-
- if (size < (1UL << PAGE_SHIFT))
- return 0;
-
- return ilog2((size) - 1) - PAGE_SHIFT + 1;
- }
-
- size--;
- size >>= PAGE_SHIFT;
-#if BITS_PER_LONG == 32
- return fls(size);
-#else
- return fls64(size);
-#endif
-}
-
-#endif /* _LINUX_LOG2_H */
projects / bcachefs-tools-debian / blobdiff