From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 71F9712B79 for ; Tue, 30 May 2023 09:01:26 +0000 (UTC) Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49FB4D9; Tue, 30 May 2023 02:01:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=0Ie8pAb6WAWCpGZTtV0SFjhCQF24hzBgUc0GiF92WMA=; b=yOYl1dtXE026ClRKhg+G1dLR2c 3DaUshOtvH6qy6QX2byxdSCO83PQ4aVKcWCA2dtZQRnfaShHB4GWiAIHROFrZB193jfHY+ofOPxUb A6tliH+tfPOYe6JWUGrSqBgBAnu1Fu9iqZN65tbF1qnSrxAHWQTSd1Eep7m20MF4I7A9oEM9YDWbe MrZp4f9myoqI+5WFOrG8z9QBCe90WmcdniIe0lSlGDCdPksGUA1trRibsHVpA3i7TeNdj3Qs/UsDL t9tMveI2x9dsALf6rD+kb5zKHnr27ySx7al6UCPDtRtNZ0rCUPFaQmrLmTxOu8dG6DgZC8k66v9Zg 1lw/JSZg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:40228) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1q3vEB-0002GA-3E; Tue, 30 May 2023 10:01:15 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1q3vE8-0007sq-D5; Tue, 30 May 2023 10:01:12 +0100 Date: Tue, 30 May 2023 10:01:12 +0100 From: "Russell King (Oracle)" To: Jakub Kicinski Cc: Andrew Lunn , Dan Carpenter , Oleksij Rempel , Heiner Kallweit , "David S. Miller" , Eric Dumazet , Paolo Abeni , netdev@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH net] net: phy: fix a signedness bug in genphy_loopback() Message-ID: References: <20230529215802.70710036@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230529215802.70710036@kernel.org> Sender: Russell King (Oracle) X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Mon, May 29, 2023 at 09:58:02PM -0700, Jakub Kicinski wrote: > On Fri, 26 May 2023 14:45:54 +0300 Dan Carpenter wrote: > > The "val" variable is used to store error codes from phy_read() so > > it needs to be signed for the error handling to work as expected. > > > > Fixes: 014068dcb5b1 ("net: phy: genphy_loopback: add link speed configuration") > > Signed-off-by: Dan Carpenter > > Is it going to be obvious to PHY-savvy folks that the val passed to > phy_read_poll_timeout() must be an int? Is it a very common pattern? > My outsider intuition is that since regs are 16b, u16 is reasonable, > and more people may make the same mistake. Therefore we should try to > fix phy_read_poll_timeout() instead to use a local variable like it > does for __ret. > > Weaker version would be to add a compile time check to ensure val > is signed (assert(typeof(val)~0ULL < 0) or such?). > > Opinions? Yes, I think that would be a saner approach, since phy_read_poll_timeout() returns the error value, rather than using the variable passed in. Andrew? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!