From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lamorak.hansenpartnership.com (lamorak.hansenpartnership.com [198.37.111.173]) (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 5489238552A; Thu, 12 Mar 2026 15:32:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.37.111.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773329562; cv=none; b=mqHb/DJurcag11SRnS5v0eXKw/B9KYnMFAy3k0LtOleIzyizQQIZGPykWB/Fmk1pYX0+BCwlxnWPlyFL0p4IAqK1AyjV+lTgP5B2vSizwLKg+5GL0Sd0YH7qCbTM9rqMlMY4753DXbwz9x4BcwiR/xWXOdqGvIlauCtTKbZdkZU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773329562; c=relaxed/simple; bh=zTDNMMg/o0AbpOakTawLJV8HRHueJx9lUWpbuHSD3BU=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; 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bh=zTDNMMg/o0AbpOakTawLJV8HRHueJx9lUWpbuHSD3BU=; h=Message-ID:Subject:From:To:Date:In-Reply-To:References:From; b=pcvJZxMlUnyDHCQWdoy7oBw4t3ApqjoLShbfu4EGfeRRF/0XvwrUC3nRWEDXXVQdM hMwbriKe/NL1VZ4m3mEc/Q/oxiEwEcX/NNUV+xlSHstrQ2AykR2/lPVz8ssLEFKVvD cNP4AXmMocQMY4pE83K1rY1dx5NyhQ9bJbZtUZWw= Received: from [IPv6:2601:5c4:4300:d341::a774] (unknown [IPv6:2601:5c4:4300:d341::a774]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lamorak.hansenpartnership.com (Postfix) with ESMTPSA id 599341C02A4; Thu, 12 Mar 2026 11:32:38 -0400 (EDT) Message-ID: Subject: Re: [PATCH 00/61] treewide: Use IS_ERR_OR_NULL over manual NULL check - refactor From: James Bottomley To: Jason Gunthorpe , Kuan-Wei Chiu Cc: Philipp Hahn , amd-gfx@lists.freedesktop.org, apparmor@lists.ubuntu.com, bpf@vger.kernel.org, ceph-devel@vger.kernel.org, cocci@inria.fr, dm-devel@lists.linux.dev, dri-devel@lists.freedesktop.org, gfs2@lists.linux.dev, intel-gfx@lists.freedesktop.org, intel-wired-lan@lists.osuosl.org, iommu@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-block@vger.kernel.org, linux-bluetooth@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-clk@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-gpio@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org, linux-media@vger.kernel.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-modules@vger.kernel.org, linux-mtd@lists.infradead.org, linux-nfs@vger.kernel.org, linux-omap@vger.kernel.org, linux-phy@lists.infradead.org, linux-pm@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, linux-sctp@vger.kernel.org, linux-security-module@vger.kernel.org, linux-sh@vger.kernel.org, linux-sound@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-trace-kernel@vger.kernel.org, linux-usb@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, ntfs3@lists.linux.dev, samba-technical@lists.samba.org, sched-ext@lists.linux.dev, target-devel@vger.kernel.org, tipc-discussion@lists.sourceforge.net, v9fs@lists.linux.dev Date: Thu, 12 Mar 2026 11:32:37 -0400 In-Reply-To: <20260312125730.GI1469476@ziepe.ca> References: <20260310-b4-is_err_or_null-v1-0-bd63b656022d@avm.de> <20260312125730.GI1469476@ziepe.ca> Autocrypt: addr=James.Bottomley@HansenPartnership.com; prefer-encrypt=mutual; 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AHBLpBdnl9SOe8ETkv6GqbZrXUED/dAbRVIT5vHP51zyYB8rAUjp3PnzxsXFG8eQaacEyKSl0DKDlgKuQ+k292LVGJhEva8z4cwg3JcrQWzbpTRskQRP624aQ7t0LKbNfXqfYT13TvZNTDdjQaCJRJ3EG8uXOszVKuc0guXunZPmmq6x1Y3bOfOezcFYoywwL3nKef+Z5sQrjG3/5NLeu+W Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.3 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2026-03-12 at 09:57 -0300, Jason Gunthorpe wrote: > On Wed, Mar 11, 2026 at 02:40:36AM +0800, Kuan-Wei Chiu wrote: >=20 > > IMHO, the necessity of IS_ERR_OR_NULL() often highlights a > > confusing or flawed API design. It usually implies that the caller > > is unsure whether a failure results in an error pointer or a NULL > > pointer.=20 >=20 > +1 >=20 > IS_ERR_OR_NULL() should always be looked on with suspicion. Very > little should be returning some tri-state 'ERR' 'NULL' 'SUCCESS' > pointer. What does the middle condition even mean? IS_ERR_OR_NULL() > implies ERR and NULL are semanticly the same, so fix the things to > always use ERR. Not in any way supporting the original patch. However, the pattern ERR, NULL, PTR is used extensively in the dentry code of filesystems.=20 See the try_lookup..() set of functions in fs/namei.c The meaning is PTR - I found it NULL - It definitely doesn't exist ERR - something went wrong during the lookup. So I don't think you can blanket say this pattern is wrong. Regards, James