move Rust sources to top level, C sources into c_src

[bcachefs-tools-debian] / include / linux / hash.h

diff --git a/include/linux/hash.h b/include/linux/hash.h
deleted file mode 100644 (file)
index ad6fa21..0000000
--- a/include/linux/hash.h
+++ /dev/null
@@ -1,104 +0,0 @@
-#ifndef _LINUX_HASH_H
-#define _LINUX_HASH_H
-/* Fast hashing routine for ints,  longs and pointers.
-   (C) 2002 Nadia Yvette Chambers, IBM */
-
-#include <asm/types.h>
-#include <linux/compiler.h>
-
-/*
- * The "GOLDEN_RATIO_PRIME" is used in ifs/btrfs/brtfs_inode.h and
- * fs/inode.c.  It's not actually prime any more (the previous primes
- * were actively bad for hashing), but the name remains.
- */
-#if BITS_PER_LONG == 32
-#define GOLDEN_RATIO_PRIME GOLDEN_RATIO_32
-#define hash_long(val, bits) hash_32(val, bits)
-#elif BITS_PER_LONG == 64
-#define hash_long(val, bits) hash_64(val, bits)
-#define GOLDEN_RATIO_PRIME GOLDEN_RATIO_64
-#else
-#error Wordsize not 32 or 64
-#endif
-
-/*
- * This hash multiplies the input by a large odd number and takes the
- * high bits.  Since multiplication propagates changes to the most
- * significant end only, it is essential that the high bits of the
- * product be used for the hash value.
- *
- * Chuck Lever verified the effectiveness of this technique:
- * http://www.citi.umich.edu/techreports/reports/citi-tr-00-1.pdf
- *
- * Although a random odd number will do, it turns out that the golden
- * ratio phi = (sqrt(5)-1)/2, or its negative, has particularly nice
- * properties.  (See Knuth vol 3, section 6.4, exercise 9.)
- *
- * These are the negative, (1 - phi) = phi**2 = (3 - sqrt(5))/2,
- * which is very slightly easier to multiply by and makes no
- * difference to the hash distribution.
- */
-#define GOLDEN_RATIO_32 0x61C88647
-#define GOLDEN_RATIO_64 0x61C8864680B583EBull
-
-#ifdef CONFIG_HAVE_ARCH_HASH
-/* This header may use the GOLDEN_RATIO_xx constants */
-#include <asm/hash.h>
-#endif
-
-/*
- * The _generic versions exist only so lib/test_hash.c can compare
- * the arch-optimized versions with the generic.
- *
- * Note that if you change these, any <asm/hash.h> that aren't updated
- * to match need to have their HAVE_ARCH_* define values updated so the
- * self-test will not false-positive.
- */
-#ifndef HAVE_ARCH__HASH_32
-#define __hash_32 __hash_32_generic
-#endif
-static inline u32 __hash_32_generic(u32 val)
-{
-       return val * GOLDEN_RATIO_32;
-}
-
-#ifndef HAVE_ARCH_HASH_32
-#define hash_32 hash_32_generic
-#endif
-static inline u32 hash_32_generic(u32 val, unsigned int bits)
-{
-       /* High bits are more random, so use them. */
-       return __hash_32(val) >> (32 - bits);
-}
-
-#ifndef HAVE_ARCH_HASH_64
-#define hash_64 hash_64_generic
-#endif
-static __always_inline u32 hash_64_generic(u64 val, unsigned int bits)
-{
-#if BITS_PER_LONG == 64
-       /* 64x64-bit multiply is efficient on all 64-bit processors */
-       return val * GOLDEN_RATIO_64 >> (64 - bits);
-#else
-       /* Hash 64 bits using only 32x32-bit multiply. */
-       return hash_32((u32)val ^ __hash_32(val >> 32), bits);
-#endif
-}
-
-static inline u32 hash_ptr(const void *ptr, unsigned int bits)
-{
-       return hash_long((unsigned long)ptr, bits);
-}
-
-/* This really should be called fold32_ptr; it does no hashing to speak of. */
-static inline u32 hash32_ptr(const void *ptr)
-{
-       unsigned long val = (unsigned long)ptr;
-
-#if BITS_PER_LONG == 64
-       val ^= (val >> 32);
-#endif
-       return (u32)val;
-}
-
-#endif /* _LINUX_HASH_H */