From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81CBDC2D0C2 for ; Fri, 3 Jan 2020 15:55:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E884217F4 for ; Fri, 3 Jan 2020 15:55:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727945AbgACPzj (ORCPT ); Fri, 3 Jan 2020 10:55:39 -0500 Received: from out30-44.freemail.mail.aliyun.com ([115.124.30.44]:55347 "EHLO out30-44.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727539AbgACPzi (ORCPT ); Fri, 3 Jan 2020 10:55:38 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R161e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07488;MF=wenyang@linux.alibaba.com;NM=1;PH=DS;RN=5;SR=0;TI=SMTPD_---0TmkQCWM_1578066930; Received: from localhost(mailfrom:wenyang@linux.alibaba.com fp:SMTPD_---0TmkQCWM_1578066930) by smtp.aliyun-inc.com(127.0.0.1); Fri, 03 Jan 2020 23:55:35 +0800 From: Wen Yang To: John Stultz , Thomas Gleixner , Stephen Boyd Cc: Wen Yang , linux-kernel@vger.kernel.org Subject: [PATCH] timekeeping: improve arithmetic divisions Date: Fri, 3 Jan 2020 23:55:17 +0800 Message-Id: <20200103155517.21754-1-wenyang@linux.alibaba.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org do_div() does a 64-by-32 division. Use div64_u64() instead of do_div() if the divisor is u64, to avoid truncation to 32-bit. Signed-off-by: Wen Yang Cc: John Stultz Cc: Thomas Gleixner Cc: Stephen Boyd Cc: linux-kernel@vger.kernel.org --- kernel/time/timekeeping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index ca69290..bad76c1 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1007,7 +1007,7 @@ static int scale64_check_overflow(u64 mult, u64 div, u64 *base) tmp *= mult; rem *= mult; - do_div(rem, div); + rem = div64_u64(rem, div); *base = tmp + rem; return 0; } -- 1.8.3.1