From 7f590657937f1c59163ff14a13062439a18e4a37 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Fri, 13 Feb 2015 14:36:19 -0800 Subject: [PATCH] lib: bitmap: remove redundant code from __bitmap_shift_left The first of these conditionals is completely redundant: If k == lim-1, we must have off==0, so the second conditional will also trigger and then it wouldn't matter if upper had some high bits set. But the second conditional is in fact also redundant, since it only serves to clear out some high-order "don't care" bits of dst, about which no guarantee is made. Signed-off-by: Rasmus Villemoes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/bitmap.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index 36e380da00c5..a13c7f4e325a 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -159,7 +159,7 @@ void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, unsigned int shift, unsigned int nbits) { int k; - unsigned int lim = BITS_TO_LONGS(nbits), left = nbits % BITS_PER_LONG; + unsigned int lim = BITS_TO_LONGS(nbits); unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG; for (k = lim - off - 1; k >= 0; --k) { unsigned long upper, lower; @@ -172,13 +172,8 @@ void __bitmap_shift_left(unsigned long *dst, const unsigned long *src, lower = src[k - 1] >> (BITS_PER_LONG - rem); else lower = 0; - upper = src[k]; - if (left && k == lim - 1) - upper &= (1UL << left) - 1; - upper <<= rem; + upper = src[k] << rem; dst[k + off] = lower | upper; - if (left && k + off == lim - 1) - dst[k + off] &= (1UL << left) - 1; } if (off) memset(dst, 0, off*sizeof(unsigned long)); -- 2.20.1