Avoid divides in BITS_TO_LONGS
BITS_PER_LONG is a signed value (32 or 64) DIV_ROUND_UP(nr, BITS_PER_LONG) performs signed arithmetic if "nr" is signed too. Converting BITS_TO_LONGS(nr) to DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) makes sure compiler can perform a right shift, even if "nr" is a signed value, instead of an expensive integer divide. Applying this patch saves 141 bytes on x86 when CONFIG_CC_OPTIMIZE_FOR_SIZE=y and speedup bitmap operations. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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