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author | George Spelvin <linux@sciencehorizons.net> | 2016-05-27 05:22:01 +0300 |
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committer | George Spelvin <linux@sciencehorizons.net> | 2016-05-28 22:42:51 +0300 |
commit | 92d567740f2ab5937b2c23bee94ea4b284bb1f98 (patch) | |
tree | cac25a2b98245c5e95cc94f8e0671b400fd9a0da /include | |
parent | 917ea166f4672ec085f2cccc135c7c0eec72282c (diff) | |
download | linux-92d567740f2ab5937b2c23bee94ea4b284bb1f98.tar.xz |
Change hash_64() return value to 32 bits
That's all that's ever asked for, and it makes the return
type of hash_long() consistent.
It also allows (upcoming patch) an optimized implementation
of hash_64 on 32-bit machines.
I tried adding a BUILD_BUG_ON to ensure the number of bits requested
was never more than 32 (most callers use a compile-time constant), but
adding <linux/bug.h> to <linux/hash.h> breaks the tools/perf compiler
unless tools/perf/MANIFEST is updated, and understanding that code base
well enough to update it is too much trouble. I did the rest of an
allyesconfig build with such a check, and nothing tripped.
Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/hash.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/linux/hash.h b/include/linux/hash.h index 79c52fa81cac..f967dedb10e2 100644 --- a/include/linux/hash.h +++ b/include/linux/hash.h @@ -48,7 +48,7 @@ #define GOLDEN_RATIO_32 0x61C88647 #define GOLDEN_RATIO_64 0x61C8864680B583EBull -static __always_inline u64 hash_64(u64 val, unsigned int bits) +static __always_inline u32 hash_64(u64 val, unsigned int bits) { u64 hash = val; @@ -72,7 +72,7 @@ static __always_inline u64 hash_64(u64 val, unsigned int bits) #endif /* High bits are more random, so use them. */ - return hash >> (64 - bits); + return (u32)(hash >> (64 - bits)); } static inline u32 hash_32(u32 val, unsigned int bits) @@ -84,7 +84,7 @@ static inline u32 hash_32(u32 val, unsigned int bits) return hash >> (32 - bits); } -static inline unsigned long hash_ptr(const void *ptr, unsigned int bits) +static inline u32 hash_ptr(const void *ptr, unsigned int bits) { return hash_long((unsigned long)ptr, bits); } |