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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E954C6FA82 for ; Tue, 13 Sep 2022 07:46:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230496AbiIMHqU (ORCPT ); Tue, 13 Sep 2022 03:46:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230342AbiIMHqR (ORCPT ); Tue, 13 Sep 2022 03:46:17 -0400 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 ECAD82B279; Tue, 13 Sep 2022 00:46:16 -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=7R46dL5v/qAAceuZ423ZSM42+lTG5q+jzS8a0ZHd/yA=; b=G4HJswNfkvqvbqgOKeKi5WXj8O JuEpK1sh7BVrm90ZMiDMwiCB3P2tVsIpxr0G2uo2fEOIkWmF+gBR61FBIk9kMY/nhTgANroSLAZsK vwmMWfq1z1Wvd3Q//G3gSYr0U6Cm7ri+g/6VvKjJZCK8fI9g4+KSMZaet8hsr9/e7omVcehR5HIIk OmUBpkhdCurtJjVThQDsEWjdLMnU9GZGEq7OyHdvC/8epR6czzdq5OAvYuMjD0TCJ81jIjEEOGMz+ YR4zt9V9DqxzeNwaIRLgIM/Iz6PObghcRWAxaXUqPYFBjGdNgZKgmQnLpuK8NexrTkw4AjL8whuZu HnN+b4mw==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:34286) 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 1oY0cS-0002aM-4j; Tue, 13 Sep 2022 08:46:08 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1oY0cQ-0000Vo-RI; Tue, 13 Sep 2022 08:46:06 +0100 Date: Tue, 13 Sep 2022 08:46:06 +0100 From: "Russell King (Oracle)" To: Lucas Stach Cc: Tang Bin , hongxing.zhu@nxp.com, lorenzo.pieralisi@arm.com, robh@kernel.org, kw@linux.com, shawnguo@kernel.org, bhelgaas@google.com, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, linux-imx@nxp.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] PCI: imx6: Fix wrong check in imx6_pcie_attach_pd() Message-ID: References: <20220913065910.15348-1-tangbin@cmss.chinamobile.com> <0660fff6d29c5f8251ac4f28d4badcfea91e6833.camel@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0660fff6d29c5f8251ac4f28d4badcfea91e6833.camel@pengutronix.de> Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 13, 2022 at 09:39:03AM +0200, Lucas Stach wrote: > Am Dienstag, dem 13.09.2022 um 14:59 +0800 schrieb Tang Bin: > > In the function imx6_pcie_attach_pd(), > > dev_pm_domain_attach_by_name() may return NULL in some cases, > > so IS_ERR() doesn't meet the requirements. Thus fix it. > > > I don't like this added complexity in the driver. IHMO if there is a > real issue, dev_pm_domain_attach_by_name() should just return a error > code, instead of NULL. You've fallen into the trap that Tang Bin laid. It returns an error code for all cases where an error has happened. It returns NULL only when the device does not require a power domain. So, a NULL return is *not* an error condition, but merely an indication that "this device does not require this power domain". Mechanical changes like this are really quite harmful to the kernel. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!