From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f169.google.com (mail-pg1-f169.google.com [209.85.215.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EB9C73B47D9 for ; Tue, 10 Mar 2026 18:40:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773168057; cv=none; b=OHGW4XCHjFXW3tExFYY+v3HzBzfgBKDhwGYzXNsFp0JcwqFySIIea/xUCEVpmLHDEBjFOFYv8VibtkQkhSCtBty/ZexVBa3L5CO/ODZOzvjPQLTB81u9+GrcIlGjcLF28KVK9ho1GVHP5XkGNY4Simxa3vLrsx07Rb7S4nCbL1s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773168057; c=relaxed/simple; bh=67BO0RZg8rxb/E50RmGcBJlsPR5Ae9xmCy+Q7v8QtDY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Tfn7rz7S6+27UbSMasHRnB4ZNKXj0pEgW2/1FT54kjQnWZB+5CBMuUY6H5KPVJDYv/jODzJzQkjzZ6E8uGiO0LgW6BqWALj9wOUrIQfmpcKmrRbtZ+A3MH0mnoBROWCx29r2ejT74VnWMeLf0gsnz77fPDGORMmdadpdOCWeHBM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=kH0xiiWz; arc=none smtp.client-ip=209.85.215.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="kH0xiiWz" Received: by mail-pg1-f169.google.com with SMTP id 41be03b00d2f7-c6dd5b01e14so4653196a12.0 for ; Tue, 10 Mar 2026 11:40:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1773168050; x=1773772850; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=bjFZ9oZWWc3RZ4UdO5rq+AZbr7uPDX73K58gh1+yuH0=; b=kH0xiiWz4KeHg8qM+UQYFRGEoaB5YhGQ1/l342lI48vVjCWqHFWSBUDJtSv8g6YdEb WUvbLXs80bxV+xnMTu2IxnxqQ1WawTtw06PwWKuvZNeHk5D3euuYdO1/s0++E4FpGP2z +c3ttwFV6WwPOQpNHM7WUIHZNaqG5koiMMCxTax1rBk+j7pB0850FJbGseMzgmcav/Sc D4sAVnEuBVkUt07E/ANMW8DM/NJ+n/hx2N6JUcXYsLZYrFMsnwCK7vKttbH8x8ketzgA AEJgLDRmf5idGKEt1ix0VwO4x51qzzz9/bjh5SLZJM6RE+ISqePxLY2ZYvsw4O/i3F73 NyLA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773168050; x=1773772850; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=bjFZ9oZWWc3RZ4UdO5rq+AZbr7uPDX73K58gh1+yuH0=; b=ZPirrKymZ3yLJ1ooEQfv4SeR3zvR178qThMz+9jQSQeQWndLIyQBVQXNIrJTfOa14Y p/oprTfN/ZRoHtYNmgIxClqTQLWm9wamX4jM1tupJXgfu1hADicsuEgVGPXw/94wpB11 JOiwEzn6EPD2YLEEd7IsjPeO9D7PgiAtKTj269QDNkBP3B+8xpO5CfrdV9HFCU8r2y4N 1tjLY3e1rCdhnoEMA4eb2vNxjDEPptW72+5WjDLAJzzc/JMsddWSdMOoc/c0vn8q2DeY BU0fyPzQ3n6qr7bk+xY1CkWYvmp80K2KswDqWBv/BQnd9X48JFuRkqkjWmteIqzFWicN 4kXA== X-Forwarded-Encrypted: i=1; AJvYcCVQLJb+q1UoDd9FL/fYYffoPQ3GJj3E6TPFiGDEZPTsCLph8tHvcc7aT1BvtknNqStMTlwpqzgEOrGfYQ==@vger.kernel.org X-Gm-Message-State: AOJu0YwCwJIxxwsV7AxTzWaCacsigwpL1giLdSTPmSMc1uShiFmVfY87 7wbfM3+/qd+JGGpBXaZwxZ9Ixf73+Zbcda9+2ASp+/XmJzm5NMq9wwLl X-Gm-Gg: ATEYQzybqGEpi1waeA1ScBF3r7FiHLDp/o1sGkbX71on30SV+mASs3MdVaCzCyJdHYn iiQvvvz/2st5L0jF29JJdNhOcEugUnhdhjYf/U7EQdbVVGJykbsFdqm0rGp28X3lPrdUAHlpyut pJL509aJ7wZV04GrZS43k+279gWK5wxY7nGVnku6CPSJph3O+5SySQD7DC1SQfhK8lxavDyftSZ L11sMhJbpKN9dTa9XNF5fSxlIwa4dmUj/rQBFq4GlNhmEGu/ww0nmSfoDcDCWzTgvB/KIS8qT18 ah2RNsuYQa+jpnhnsabzrGDVIFb/EgnELES76A30TuHYN4Nd52yPp0lx2nd8wFN2IHkixrOEgSJ gvpMgPOSfHeqSPpYFBIwO1VxzPKv2o65X2Cy2wZq9P9PT9tY6NMvHA4yegiM3GwQfD4JzJNZiUP c4EfL8ctqoy9tWf4Bz/zh4vy8XYaTAB2bC7jpMTfe5BMsqLA== X-Received: by 2002:a17:903:28c8:b0:2ae:5671:7071 with SMTP id d9443c01a7336-2ae8252cf0fmr96662285ad.43.1773168050081; Tue, 10 Mar 2026 11:40:50 -0700 (PDT) Received: from google.com ([2402:7500:a44:85b:2953:97d3:b283:95c3]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2ae83e58592sm220535625ad.14.2026.03.10.11.40.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Mar 2026 11:40:49 -0700 (PDT) Date: Wed, 11 Mar 2026 02:40:36 +0800 From: Kuan-Wei Chiu To: Philipp Hahn Cc: 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 Subject: Re: [PATCH 00/61] treewide: Use IS_ERR_OR_NULL over manual NULL check - refactor Message-ID: References: <20260310-b4-is_err_or_null-v1-0-bd63b656022d@avm.de> Precedence: bulk X-Mailing-List: linux-btrfs@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: <20260310-b4-is_err_or_null-v1-0-bd63b656022d@avm.de> Hi Philipp, On Tue, Mar 10, 2026 at 12:48:26PM +0100, Philipp Hahn wrote: > While doing some static code analysis I stumbled over a common pattern, > where IS_ERR() is combined with a NULL check. For that there is > IS_ERR_OR_NULL(). > > I've written a Coccinelle patch to find and patch those instances. > The patches follow grouped by subsystem. > > Patches 55-58 may be dropped as they have a (minor?) semantic change: > They use WARN_ON() or WARN_ON_ONCE(), but only in the IS_ERR() path, not > for the NULL check. Iff it is okay to print the warning also for NULL, > then the patches can be applied. > > While generating the patch set `checkpatch` complained about mixing > [un]likely() with IS_ERR_OR_NULL(), which already uses likely() > internally. I found and fixed several locations, where that combination > has been used. Thanks for the patchset. However, I think we need a explanation for why switching to IS_ERR_OR_NULL() is an improvement over the existing code. 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. Rather than doing a treewide conversion of this pattern, I believe it would be much more meaningful to review these instances case-by-case and fix the underlying APIs or caller logic instead. Additionally, a treewide refactoring like this has the practical drawback of creating unnecessary merge conflicts when backporting to stable trees. Regards, Kuan-Wei