From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752111AbaK1QCJ (ORCPT ); Fri, 28 Nov 2014 11:02:09 -0500 Received: from mail-la0-f43.google.com ([209.85.215.43]:44736 "EHLO mail-la0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752090AbaK1QCG (ORCPT ); Fri, 28 Nov 2014 11:02:06 -0500 From: Rasmus Villemoes To: Andrew Morton , Jan Kara Cc: linux-kernel@vger.kernel.org Subject: [PATCH 7/7] lib: bitmap: Remove redundant code from __bitmap_shift_left Date: Fri, 28 Nov 2014 17:01:10 +0100 Message-Id: <1417190476-18066-8-git-send-email-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.0.4 In-Reply-To: <1417190476-18066-1-git-send-email-linux@rasmusvillemoes.dk> References: <1417190476-18066-1-git-send-email-linux@rasmusvillemoes.dk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- lib/bitmap.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index 2362601..acea8ae 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -157,7 +157,7 @@ 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; @@ -170,13 +170,8 @@ 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)); -- 2.0.4