lib: bitmap: change bitmap_shift_left to take unsigned parameters
authorRasmus Villemoes <linux@rasmusvillemoes.dk>
Fri, 13 Feb 2015 22:36:13 +0000 (14:36 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 14 Feb 2015 05:21:35 +0000 (21:21 -0800)
commitdba94c2553da1928303c2a6c6410247c88cafc1d
treef6721644e3f883db6d2edccffad73756941b8c00
parentcfac1d080a00544e5cecd2d7c9ebe3d6a5cc18e6
lib: bitmap: change bitmap_shift_left to take unsigned parameters

gcc can generate slightly better code for stuff like "nbits %
BITS_PER_LONG" when it knows nbits is not negative.  Since negative size
bitmaps or shift amounts don't make sense, change these parameters of
bitmap_shift_right to unsigned.

If off >= lim (which requires shift >= nbits), k is initialized with a
large positive value, but since I've let k continue to be signed, the loop
will never run and dst will be zeroed as expected.  Inside the loop, k is
guaranteed to be non-negative, so the fact that it is promoted to unsigned
in the various expressions it appears in is harmless.

Also use "shift" and "nbits" consistently for the parameter names.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/bitmap.h
lib/bitmap.c