From patchwork Tue Jan 28 14:07:47 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 1230387 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=ISWilGku; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 486TTg6n39zB3wF for ; Wed, 29 Jan 2020 01:27:19 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733128AbgA1O1N (ORCPT ); Tue, 28 Jan 2020 09:27:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:54840 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733097AbgA1O1L (ORCPT ); Tue, 28 Jan 2020 09:27:11 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E099720716; Tue, 28 Jan 2020 14:27:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580221630; bh=hNUuSpR/k3+mdub8eIuCkfnODaICqkGo37Nmkd2O/UM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ISWilGkufwaUfniMpPdGShuokXNScvrpGCxHT5bGwl2qszlgZcyppQEy1G5oV/BOh n+K5muT33rBJAlc5PZxw8YbcyaxLU+Wv2pe3qdlpGaIa9oNGvn9fRILXsje/7YxuIU 2erTQkjaQXgQZoewh7aBrbuhjinJnU/sarEEMy8w= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wen Yang , Eric Dumazet , "David S. Miller" , Alexey Kuznetsov , Hideaki YOSHIFUJI , netdev@vger.kernel.org Subject: [PATCH 4.19 19/92] tcp_bbr: improve arithmetic division in bbr_update_bw() Date: Tue, 28 Jan 2020 15:07:47 +0100 Message-Id: <20200128135811.615398397@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200128135809.344954797@linuxfoundation.org> References: <20200128135809.344954797@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Wen Yang [ Upstream commit 5b2f1f3070b6447b76174ea8bfb7390dc6253ebd ] 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 Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_bbr.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/net/ipv4/tcp_bbr.c +++ b/net/ipv4/tcp_bbr.c @@ -680,8 +680,7 @@ static void bbr_update_bw(struct sock *s * 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