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 B5D9EC2D0DB for ; Mon, 20 Jan 2020 10:05:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9448322525 for ; Mon, 20 Jan 2020 10:05:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727130AbgATKFV (ORCPT ); Mon, 20 Jan 2020 05:05:21 -0500 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:57837 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726075AbgATKFV (ORCPT ); Mon, 20 Jan 2020 05:05:21 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R301e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=wenyang@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0ToE1bps_1579514711; Received: from localhost(mailfrom:wenyang@linux.alibaba.com fp:SMTPD_---0ToE1bps_1579514711) by smtp.aliyun-inc.com(127.0.0.1); Mon, 20 Jan 2020 18:05:18 +0800 From: Wen Yang To: Eric Dumazet , davem@davemloft.net Cc: Wen Yang , Alexey Kuznetsov , Hideaki YOSHIFUJI , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] tcp_bbr: improve arithmetic division in bbr_update_bw() Date: Mon, 20 Jan 2020 18:04:56 +0800 Message-Id: <20200120100456.45609-1-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_long() instead of it if the divisor is long, to avoid truncation to 32-bit. And as a nice side effect also cleans up the function a bit. Signed-off-by: Wen Yang Cc: Eric Dumazet Cc: "David S. Miller" Cc: Alexey Kuznetsov Cc: Hideaki YOSHIFUJI Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- net/ipv4/tcp_bbr.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c index a6545ef0d27b..6c4d79baff26 100644 --- a/net/ipv4/tcp_bbr.c +++ b/net/ipv4/tcp_bbr.c @@ -779,8 +779,7 @@ static void bbr_update_bw(struct sock *sk, const struct rate_sample *rs) * bandwidth sample. Delivered is in packets and interval_us in uS and * ratio will be <<1 for most connections. So delivered is first scaled. */ - bw = (u64)rs->delivered * BW_UNIT; - do_div(bw, rs->interval_us); + bw = div64_long((u64)rs->delivered * BW_UNIT, rs->interval_us); /* If this sample is application-limited, it is likely to have a very * low delivered count that represents application behavior rather than -- 2.23.0