tree a48eaac7da2877aa5600e5b4e99dedabd4b4b6fb
parent cdac75e6f2fec9abc21d0abb4e5d80720eeebb10
author Eric Dumazet <dada1@cosmosbay.com> 1209455915 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1209481559 -0700

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>