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=-14.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 8B5CAC4338F for ; Sat, 14 Aug 2021 13:19:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 62EB760F48 for ; Sat, 14 Aug 2021 13:19:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238426AbhHNNTg (ORCPT ); Sat, 14 Aug 2021 09:19:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235352AbhHNNTb (ORCPT ); Sat, 14 Aug 2021 09:19:31 -0400 Received: from mail-lj1-x232.google.com (mail-lj1-x232.google.com [IPv6:2a00:1450:4864:20::232]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0B4DC061764; Sat, 14 Aug 2021 06:19:01 -0700 (PDT) Received: by mail-lj1-x232.google.com with SMTP id n6so19896669ljp.9; Sat, 14 Aug 2021 06:19:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=cr8HVeHd12HLdO05fgAd9qzil9aAvneqAPuVADXCz+s=; b=Ir6VbEE8D+BMdy/dwWslbPOHaadgd5AtkG34R4WbL9h+QlVSITnwLPADVSEvAD6ZM5 w18seqNcss0OkHdk0tiYzTdcxugHit8o0WUbGtB7alv+pWlFCRKlhCOwtOaV0ZJt21+b iZMpau+Z7HDME1C5keyoRapiYzPK9Inp8xvrdu+CSX9qG6VLVtogFFrO9+uEfFRw+fOF Y/zjei6hspHQPOWeOn+YBi+yhC6vx6q1EPsOI1ABpw2Cs2XHlnCycAlR8EUhCbMzkOp0 hF85HliqJZUIisBk6HyRLJqvE6rchL1wcaNgTLeCMa7S/7wZB075UDfki2+R/mcbLAwP h2PA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=cr8HVeHd12HLdO05fgAd9qzil9aAvneqAPuVADXCz+s=; b=HNvDZ4pNpOevcpUquhzW9rdbm66TswCi36xQgK3EOq2g3pB5AnAOMapyMq4vCRdwjG t+Vo8Pc7VVPwweSP6NoIFHNQvSilXbiXs2SG1sjM7PCdkQbiXbCoyPC5LLbKpHKA0FEP R6JKb2N4fLygf9afuGPojy0+jjzy+/9chFC85hs5317zn85IOvzdwQabzMsJK6ssnT3q mzZ+UhdazS1eyD1bcusCMXt6DlP+E9mRjGlre8yeBUc3JW/WcM12sDgkdrQ1/KEe2gQi MVb1VY3O6unyezxXLTOs8Y/mcs/cDa6ZeBn3k+/Lm8xriQNuGeRTFm7DATkq2Do54T6u IO+A== X-Gm-Message-State: AOAM533ntvU7wdAFM3sCzAX6aiNUQLe9DAIwIKoPiTkn05CoUKEF5//1 9oBbOtIfuK0LAAVc1T6Gjfijw9p7lp/qLh5a X-Google-Smtp-Source: ABdhPJwTk6ewrNbWZcok8gU6/Xcfk8pw07gonhRWx0gU7USSrI9j6n7RMCiLkjAVadqDallh2KhUSw== X-Received: by 2002:a2e:9585:: with SMTP id w5mr5471976ljh.124.1628947140172; Sat, 14 Aug 2021 06:19:00 -0700 (PDT) Received: from localhost.localdomain ([185.215.60.122]) by smtp.gmail.com with ESMTPSA id f23sm537455ljn.45.2021.08.14.06.18.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 14 Aug 2021 06:18:59 -0700 (PDT) Subject: Re: [PATCH] net: usb: pegasus: ignore the return value from set_registers(); To: Jakub Kicinski , Petko Manolov Cc: netdev@vger.kernel.org, stable@vger.kernel.org, davem@davemloft.net References: <20210812082351.37966-1-petko.manolov@konsulko.com> <20210813162439.1779bf63@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> From: Pavel Skripkin Message-ID: <9688d41f-a9f0-47f3-5f51-5c7981f5337e@gmail.com> Date: Sat, 14 Aug 2021 16:18:58 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <20210813162439.1779bf63@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 8/14/21 2:24 AM, Jakub Kicinski wrote: > On Thu, 12 Aug 2021 11:23:51 +0300 Petko Manolov wrote: >> The return value need to be either ignored or acted upon, otherwise 'deadstore' >> clang check would yell at us. I think it's better to just ignore what this >> particular call of set_registers() returns. The adapter defaults are sane and >> it would be operational even if the register write fail. >> >> Signed-off-by: Petko Manolov >> --- >> drivers/net/usb/pegasus.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/net/usb/pegasus.c b/drivers/net/usb/pegasus.c >> index 652e9fcf0b77..49cfc720d78f 100644 >> --- a/drivers/net/usb/pegasus.c >> +++ b/drivers/net/usb/pegasus.c >> @@ -433,7 +433,7 @@ static int enable_net_traffic(struct net_device *dev, struct usb_device *usb) >> data[2] = loopback ? 0x09 : 0x01; >> >> memcpy(pegasus->eth_regs, data, sizeof(data)); >> - ret = set_registers(pegasus, EthCtrl0, 3, data); >> + set_registers(pegasus, EthCtrl0, 3, data); >> >> if (usb_dev_id[pegasus->dev_index].vendor == VENDOR_LINKSYS || >> usb_dev_id[pegasus->dev_index].vendor == VENDOR_LINKSYS2 || > > This one is not added by the recent changes as I initially thought, > the driver has always checked this return value. The recent changes > did this: > > ret = set_registers(pegasus, EthCtrl0, 3, data); > > if (usb_dev_id[pegasus->dev_index].vendor == VENDOR_LINKSYS || > usb_dev_id[pegasus->dev_index].vendor == VENDOR_LINKSYS2 || > usb_dev_id[pegasus->dev_index].vendor == VENDOR_DLINK) { > u16 auxmode; > - read_mii_word(pegasus, 0, 0x1b, &auxmode); > + ret = read_mii_word(pegasus, 0, 0x1b, &auxmode); > + if (ret < 0) > + goto fail; > auxmode |= 4; > write_mii_word(pegasus, 0, 0x1b, &auxmode); > } > > + return 0; > +fail: > + netif_dbg(pegasus, drv, pegasus->net, "%s failed\n", __func__); > return ret; > } > > now the return value of set_registeres() is ignored. > > Seems like a better fix would be to bring back the error checking, > why not? > > Please remember to add a fixes tag. > Hi, Jakub! I've suggested to handle this error, but Petko said that device won't stop working, it will just get in non-optimal state. https://lore.kernel.org/lkml/YRF1t5kx6hTrv5LC@carbon/ With regards, Pavel Skripkin