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| author | Matthew Wilcox <mawilcox@microsoft.com> | 2017-07-10 15:51:35 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-10 16:32:34 -0700 |
| commit | 2c6deb01525ac11cc03c44fe31e3f45ce2cadaf9 (patch) | |
| tree | 3ec33e9980028a7d01f54772b0a7ce60db55c39c /include/linux/bitmap.h | |
| parent | 2a98dc028f911a7c59c87d11d4eed6626be1605b (diff) | |
| download | linux-stable-2c6deb01525ac11cc03c44fe31e3f45ce2cadaf9.tar.gz linux-stable-2c6deb01525ac11cc03c44fe31e3f45ce2cadaf9.tar.bz2 linux-stable-2c6deb01525ac11cc03c44fe31e3f45ce2cadaf9.zip | |
bitmap: use memcmp optimisation in more situations
Commit 7dd968163f7c ("bitmap: bitmap_equal memcmp optimization") was
rather more restrictive than necessary; we can use memcmp() to implement
bitmap_equal() as long as the number of bits can be proved to be a
multiple of 8. And architectures other than s390 may be able to make
good use of this optimisation.
[arnd@arndb.de: fix build: add a memcmp() declaration]
Link: http://lkml.kernel.org/r/20170630153908.3439707-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20170628153221.11322-5-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/bitmap.h')
| -rw-r--r-- | include/linux/bitmap.h | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index c04c9d155e59..5797ca6fdfe2 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -266,10 +266,8 @@ static inline int bitmap_equal(const unsigned long *src1, { if (small_const_nbits(nbits)) return !((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits)); -#ifdef CONFIG_S390 - if (__builtin_constant_p(nbits) && (nbits % BITS_PER_LONG) == 0) + if (__builtin_constant_p(nbits & 7) && IS_ALIGNED(nbits, 8)) return !memcmp(src1, src2, nbits / 8); -#endif return __bitmap_equal(src1, src2, nbits); } |