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=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 CFDF4C4320A for ; Fri, 13 Aug 2021 23:24:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC646610CF for ; Fri, 13 Aug 2021 23:24:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235659AbhHMXZJ (ORCPT ); Fri, 13 Aug 2021 19:25:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:33666 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235330AbhHMXZI (ORCPT ); Fri, 13 Aug 2021 19:25:08 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 79A3E60230; Fri, 13 Aug 2021 23:24:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628897080; bh=VNBCMbuXdLAiF1wcrCYDIMMMtxoYtb8j99FAxFhqMQc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=YKD3pasHdkXskbpxrooVBA++dVkrO08X/WTciCt+/ztWye3aYNTqzUUOSj/nhCjZU 6uKznyZ0iSkB/mhRMU5wLuEIHLrGi/CdKNMKX5NEE6QwWzlLl2j14+8YRUMn+1ME+7 wAXsa+sYE+yBXjYXQCmWoh33Mador0oeQuQmOYcg9+zrARrJld5RUxse5TK8nzpxv6 6D7LIg2aHNdjrD+v5pC+ulg3WTtwNepHTB6v9JKh+el3UMkMTDc/S7Eqa9uu3+JzUT 2erRfQq+Sr9NjyL8cLJbe4ZcPdcUYLsgvj/7Ag7D648E5nMQzCuf47c3hD2KDy5baY cpynXsZOQhR/A== Date: Fri, 13 Aug 2021 16:24:39 -0700 From: Jakub Kicinski To: Petko Manolov Cc: netdev@vger.kernel.org, paskripkin@gmail.com, stable@vger.kernel.org, davem@davemloft.net Subject: Re: [PATCH] net: usb: pegasus: ignore the return value from set_registers(); Message-ID: <20210813162439.1779bf63@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: <20210812082351.37966-1-petko.manolov@konsulko.com> References: <20210812082351.37966-1-petko.manolov@konsulko.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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.