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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,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 2596BC433E0 for ; Fri, 5 Mar 2021 04:07:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB0E165013 for ; Fri, 5 Mar 2021 04:07:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229741AbhCEEHS (ORCPT ); Thu, 4 Mar 2021 23:07:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42164 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229463AbhCEEHS (ORCPT ); Thu, 4 Mar 2021 23:07:18 -0500 Received: from mail-ot1-x32d.google.com (mail-ot1-x32d.google.com [IPv6:2607:f8b0:4864:20::32d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79C85C061756 for ; Thu, 4 Mar 2021 20:07:16 -0800 (PST) Received: by mail-ot1-x32d.google.com with SMTP id d9so527555ote.12 for ; Thu, 04 Mar 2021 20:07:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=g2X3AuyS9pE7ney+yblpjXrUEFgN6B0LhuiKB+8C6j0=; b=l/+cAui14+nB7D+m/sfh68LTZXT+BoYCuLhsKYjhD9JfvmIHQ4b011TqbRm2jmscQc +80zUf7mAUDIp4jLhWh6/Tg/IzM+bv3LGMJaZXXd89ExVF+Gf9NqcGK+3RZi9+O1znDx xry+M51zEbftdbh9+SVLEimRUkNDyVKN9lZBUYxdAgjv5NXTdCpz75nDCo2ZWonwx7h7 TGFWYnvlgSzVQIIfBd1fefoROaKgfE20+bcPRwx4Lhd01nFY7QJt+CIFUd7DSi6j+7xB dWTlwYDUN+gQm8+5wUREFB55o8VFKjXnY+QDEaUp3zZtqsnPx6gvV8GwoPhbHB+a09VI Oh5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=g2X3AuyS9pE7ney+yblpjXrUEFgN6B0LhuiKB+8C6j0=; b=CSHGbffx8Tb6uKesk3RtdMFphBVBmdHZEonzVgO1KIVNrWn0kUnl+TakxwMihelvWK H1KJtU5IZkustFXy/8IAuZ8EhIu2HxjTDET+S63ExBdUUGpf9PM3eoO79VYKidK2XyER /vcrbBSVT8i2Rar6wdmsGu/vjWRcJ4hvlwvQ4tqKDKzh5jzhZtWxlnxHHjDQVpt9wjCg WyTceoY26dZbS0sBM/VZw2U7k2MGSybxHdKiD19CN19dqHUNPu2E2kDGNet1UA9cKKww qEXrCVwBj5M+8uUYWXHLMick9oGGY2TgvQ4ZXL0VsoEjTqxVf+UXvN9BKMet6SO7tEUR 6HFw== X-Gm-Message-State: AOAM533cdeRGgNiNBJnQqLGVyUil8+m+qZ5ott2EGQ/UYPaLULTHV5GP cJ+nq978QqKqZI2THHEAQT22PA== X-Google-Smtp-Source: ABdhPJzwBPs6wvWsm27RwtgAjbWHeKN4hGUqDR46f7Eiu0YSpf+/VPwLOfH75cJImSiyaO3EBcuJ4g== X-Received: by 2002:a05:6830:2119:: with SMTP id i25mr6086111otc.249.1614917235811; Thu, 04 Mar 2021 20:07:15 -0800 (PST) Received: from builder.lan (104-57-184-186.lightspeed.austtx.sbcglobal.net. [104.57.184.186]) by smtp.gmail.com with ESMTPSA id s21sm339104oos.5.2021.03.04.20.07.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Mar 2021 20:07:15 -0800 (PST) Date: Thu, 4 Mar 2021 22:07:13 -0600 From: Bjorn Andersson To: Alex Elder Cc: subashab@codeaurora.org, stranche@codeaurora.org, davem@davemloft.net, kuba@kernel.org, sharathv@codeaurora.org, evgreen@chromium.org, cpratapa@codeaurora.org, elder@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next 2/6] net: qualcomm: rmnet: simplify some byte order logic Message-ID: References: <20210304223431.15045-1-elder@linaro.org> <20210304223431.15045-3-elder@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210304223431.15045-3-elder@linaro.org> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu 04 Mar 16:34 CST 2021, Alex Elder wrote: > In rmnet_map_ipv4_ul_csum_header() and rmnet_map_ipv6_ul_csum_header() > the offset within a packet at which checksumming should commence is > calculated. This calculation involves byte swapping and a forced type > conversion that makes it hard to understand. > > Simplify this by computing the offset in host byte order, then > converting the result when assigning it into the header field. > > Signed-off-by: Alex Elder > --- > .../ethernet/qualcomm/rmnet/rmnet_map_data.c | 22 ++++++++++--------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c > index 21d38167f9618..bd1aa11c9ce59 100644 > --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c > +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c > @@ -197,12 +197,13 @@ rmnet_map_ipv4_ul_csum_header(void *iphdr, > struct rmnet_map_ul_csum_header *ul_header, > struct sk_buff *skb) > { > - struct iphdr *ip4h = (struct iphdr *)iphdr; > - __be16 *hdr = (__be16 *)ul_header, offset; > + __be16 *hdr = (__be16 *)ul_header; > + struct iphdr *ip4h = iphdr; > + u16 offset; > + > + offset = skb_transport_header(skb) - (unsigned char *)iphdr; > + ul_header->csum_start_offset = htons(offset); > > - offset = htons((__force u16)(skb_transport_header(skb) - Just curious, why does this require a __force, or even a cast? Regardless, your proposed way of writing it is easier to read. Reviewed-by: Bjorn Andersson Regards, Bjorn > - (unsigned char *)iphdr)); > - ul_header->csum_start_offset = offset; > ul_header->csum_insert_offset = skb->csum_offset; > ul_header->csum_enabled = 1; > if (ip4h->protocol == IPPROTO_UDP) > @@ -239,12 +240,13 @@ rmnet_map_ipv6_ul_csum_header(void *ip6hdr, > struct rmnet_map_ul_csum_header *ul_header, > struct sk_buff *skb) > { > - struct ipv6hdr *ip6h = (struct ipv6hdr *)ip6hdr; > - __be16 *hdr = (__be16 *)ul_header, offset; > + __be16 *hdr = (__be16 *)ul_header; > + struct ipv6hdr *ip6h = ip6hdr; > + u16 offset; > + > + offset = skb_transport_header(skb) - (unsigned char *)ip6hdr; > + ul_header->csum_start_offset = htons(offset); > > - offset = htons((__force u16)(skb_transport_header(skb) - > - (unsigned char *)ip6hdr)); > - ul_header->csum_start_offset = offset; > ul_header->csum_insert_offset = skb->csum_offset; > ul_header->csum_enabled = 1; > > -- > 2.20.1 >