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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=unavailable 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 BE4F6C43381 for ; Thu, 21 Mar 2019 21:00:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 922B5218D3 for ; Thu, 21 Mar 2019 21:00:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727468AbfCUU76 (ORCPT ); Thu, 21 Mar 2019 16:59:58 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:53240 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726823AbfCUU75 (ORCPT ); Thu, 21 Mar 2019 16:59:57 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 5015B133E9775; Thu, 21 Mar 2019 13:59:56 -0700 (PDT) Date: Thu, 21 Mar 2019 13:59:55 -0700 (PDT) Message-Id: <20190321.135955.1938105690350887430.davem@davemloft.net> To: linyunsheng@huawei.com Cc: huangdaode@hisilicon.com, xuwei5@hisilicon.com, liguozhu@hisilicon.com, Yisen.Zhuang@huawei.com, john.garry@huawei.com, linuxarm@huawei.com, salil.mehta@huawei.com, lipeng321@huawei.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net] net: hns3: fix for not calculating tx bd num correctly From: David Miller In-Reply-To: <1553138923-122549-1-git-send-email-linyunsheng@huawei.com> References: <1553138923-122549-1-git-send-email-linyunsheng@huawei.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 21 Mar 2019 13:59:56 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: l00371289 Date: Thu, 21 Mar 2019 11:28:43 +0800 > From: Yunsheng Lin > > When there is only one byte in a frag, the current calculation > using "(size + HNS3_MAX_BD_SIZE - 1) >> HNS3_MAX_BD_SIZE_OFFSET" > will return zero, because HNS3_MAX_BD_SIZE is 65535 and > HNS3_MAX_BD_SIZE_OFFSET is 16. So it will cause tx error when > a frag's size is one byte. > > This patch fixes it by using DIV_ROUND_UP. > > Fixes: 3fe13ed95dd3 ("net: hns3: avoid mult + div op in critical data path") > Signed-off-by: Yunsheng Lin Applied.