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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 4DDFEC11F6A for ; Tue, 29 Jun 2021 13:37:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2BA8961D90 for ; Tue, 29 Jun 2021 13:37:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234074AbhF2Njl (ORCPT ); Tue, 29 Jun 2021 09:39:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33916 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232989AbhF2Nje (ORCPT ); Tue, 29 Jun 2021 09:39:34 -0400 Received: from mail-pl1-x632.google.com (mail-pl1-x632.google.com [IPv6:2607:f8b0:4864:20::632]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 80F39C061760; Tue, 29 Jun 2021 06:37:06 -0700 (PDT) Received: by mail-pl1-x632.google.com with SMTP id z4so1605747plg.8; Tue, 29 Jun 2021 06:37:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=zio1lOhtG4EyFNe7HsOIIbxHd7wmDa19V1E41XFuv1o=; b=QKqCSEbf3r5/3ahfxkCWiGFGWMm2Gv2lEAIFmzvp6SohntKV+rz/kKv4TsSqFDMmqJ x2d29scCzZEI9dBPJCiS3U0tRQC12fdJbUAbL9LDs21f04ftV2mQ+DyY/ikZh0MCXsRS qO9MH9rpeiObY6b3ShJyUi+cNDTt3uKN6kxNg9SV5/+hM5pMuKqUTM3UTb+iEkeALkUV qdbIYUwIExxLXIhB/DbFu3T5EJ9MqgryNjGcJftUaN+eoSA4S7V5/XVT/6UNUsgzEKU5 pAKiRaWwDJf6b8LWnFPcU0qOsc6EHAJ60+hZr+KkBZ6nwbWlb/9f0q0QWgIHW26V4+iL rPrw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=zio1lOhtG4EyFNe7HsOIIbxHd7wmDa19V1E41XFuv1o=; b=RlicZLgu8Vf9J6bdz1HlAgVWzQnyM8FUp6565vFNa8QQd5ZelSIeW+WIBiV5xfpjtB MUF04PFaW6vYlb255BUd497i6YARCBROBSxXxcefgLiR026nm6AcJByDDkhUD3x00hka kPRzak9J2KWYWL1vp8Huml4DzXOqYnOZ2P0dax4JqbwVvHBvJo1TQQqVhCuLPkCgrHs2 kWWjd0ugwZP33cuBXTopTbAqyfjbG/EHj3qmri1EXG4N2SUMFaLitKa32JWicCkJZj+j 0XI+2fFCqvf9F3UJJrvS2ILaK4KuLyETvk74lPA8MMmKOPUsBWwLc3gDEGPcYGsTKvMz bmew== X-Gm-Message-State: AOAM5303GdCX1pnsBXS9oesbzMRxtAe1zJX2V8xUx6igjGTVI7HwPXtJ u2+nknLhjSbnV986sUmCGIY= X-Google-Smtp-Source: ABdhPJxT9XmVbs1wB+Pc8OCoEZk0cTF8wXN2v0ua6UfCpRvCCjvao0T2oxjaCqTrrcdWeD8WjxoTLw== X-Received: by 2002:a17:902:ea0e:b029:128:ad9a:8c68 with SMTP id s14-20020a170902ea0eb0290128ad9a8c68mr17955940plg.68.1624973825988; Tue, 29 Jun 2021 06:37:05 -0700 (PDT) Received: from localhost ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id m2sm3549327pja.9.2021.06.29.06.37.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Jun 2021 06:37:05 -0700 (PDT) From: Coiby Xu X-Google-Original-From: Coiby Xu Date: Tue, 29 Jun 2021 21:35:41 +0800 To: Dan Carpenter Cc: linux-staging@lists.linux.dev, netdev@vger.kernel.org, Benjamin Poirier , Shung-Hsi Yu , Manish Chopra , "supporter:QLOGIC QLGE 10Gb ETHERNET DRIVER" , Greg Kroah-Hartman , open list Subject: Re: [RFC 16/19] staging: qlge: remove deadcode in qlge_build_rx_skb Message-ID: <20210629133541.2n3rr7vzglcoy56x@Rk> References: <20210621134902.83587-1-coiby.xu@gmail.com> <20210621134902.83587-17-coiby.xu@gmail.com> <20210622072939.GL1861@kadam> <20210624112500.rhtqp7j3odq6b6bq@Rk> <20210624124926.GI1983@kadam> <20210627105349.pflw2r2b4qus64kf@Rk> <20210628064645.GK2040@kadam> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20210628064645.GK2040@kadam> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 28, 2021 at 09:46:45AM +0300, Dan Carpenter wrote: >On Sun, Jun 27, 2021 at 06:53:49PM +0800, Coiby Xu wrote: >> On Thu, Jun 24, 2021 at 03:49:26PM +0300, Dan Carpenter wrote: >> > On Thu, Jun 24, 2021 at 07:25:00PM +0800, Coiby Xu wrote: >> > > On Tue, Jun 22, 2021 at 10:29:39AM +0300, Dan Carpenter wrote: >> > > > On Mon, Jun 21, 2021 at 09:48:59PM +0800, Coiby Xu wrote: >> > > > > This part of code is for the case that "the headers and data are in >> > > > > a single large buffer". However, qlge_process_mac_split_rx_intr is for >> > > > > handling packets that packets underwent head splitting. In reality, with >> > > > > jumbo frame enabled, the part of code couldn't be reached regardless of >> > > > > the packet size when ping the NIC. >> > > > > >> > > > >> > > > This commit message is a bit confusing. We're just deleting the else >> > > > statement. Once I knew that then it was easy enough to review >> > > > qlge_process_mac_rx_intr() and see that if if >> > > > ib_mac_rsp->flags3 & IB_MAC_IOCB_RSP_DL is set then >> > > > ib_mac_rsp->flags4 & IB_MAC_IOCB_RSP_HV must be set. >> > > >> > > Do you suggest moving to upper if, i.e. >> > > >> > > } else if (ib_mac_rsp->flags3 & IB_MAC_IOCB_RSP_DL && ib_mac_rsp->flags4 & IB_MAC_IOCB_RSP_HS) { >> > > >> > > and then deleting the else statement? >> > > >> > >> > I have a rule that when people whinge about commit messages they should >> > write a better one themselves, but I have violated my own rule. Sorry. >> > Here is my suggestion: >> > >> > If the "ib_mac_rsp->flags3 & IB_MAC_IOCB_RSP_DL" condition is true >> > then we know that "ib_mac_rsp->flags4 & IB_MAC_IOCB_RSP_HS" must be >> > true as well. Thus, we can remove that condition and delete the >> > else statement which is dead code. >> > >> > (Originally this code was for the case that "the headers and data are >> > in a single large buffer". However, qlge_process_mac_split_rx_intr >> > is for handling packets that packets underwent head splitting). >> >> Thanks for sharing your commit message! Now I see what you mean. But I'm >> not sure if "ib_mac_rsp->flags4 & IB_MAC_IOCB_RSP_HS" is true when >> "ib_mac_rsp->flags3 & IB_MAC_IOCB_RSP_DL" is true. > >Well... It is true. qlge_process_mac_split_rx_intr() is only called >when "->flags4 & IB_MAC_IOCB_RSP_HS" is true or when >"->flags3 & IB_MAC_IOCB_RSP_DL" is false. Actually qlge_process_mac_rx_intr calls qlge_process_mac_split_rx_intr when "ib_mac_rsp->flags4 & IB_MAC_IOCB_RSP_HV" is true or in the last else, /* Process an inbound completion from an rx ring. */ static unsigned long qlge_process_mac_rx_intr(struct qlge_adapter *qdev, struct rx_ring *rx_ring, struct qlge_ib_mac_iocb_rsp *ib_mac_rsp) { ... if (ib_mac_rsp->flags4 & IB_MAC_IOCB_RSP_HV) { /* The data and headers are split into * separate buffers. */ qlge_process_mac_split_rx_intr(qdev, rx_ring, ib_mac_rsp, vlan_id); } else if (ib_mac_rsp->flags3 & IB_MAC_IOCB_RSP_DS) { ... } else { /* Non-TCP/UDP large frames that span multiple buffers * can be processed corrrectly by the split frame logic. */ qlge_process_mac_split_rx_intr(qdev, rx_ring, ib_mac_rsp, vlan_id); } So I think we can't say that if "ib_mac_rsp->flags4 & IB_MAC_IOCB_RSP_HV" is true, then "ib_mac_rsp->flags4 & IB_MAC_IOCB_RSP_HS" must be true. And I don't know how to reach the conclusion that the last else means "->flags3 & IB_MAC_IOCB_RSP_DL" is false. > >To me the fact that it's clearly dead code, helps me to verify that the >patch doesn't change behavior. Anyway, "this part of code" was a bit >vague and it took me a while to figure out the patch deletes the else >statement. > >regards, >dan carpenter > -- Best regards, Coiby