From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f170.google.com (mail-pg1-f170.google.com [209.85.215.170]) (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 1B2703B5310 for ; Tue, 10 Mar 2026 18:40:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.170 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773168054; cv=none; b=crsvpebP2aTC9krKneR5XHdlbPp6v0Zm1UxPyP4+WJxkHOgjSDPEzpKZvvkUwu+OU5tcnbKhZN6twnu12lp/Pr9qo1LEPVvg7Uk6xOwWPPxKl6OoMyBGYZiMRrjAS4IrCSjSSaM+nJNjVA95BwqB7L73UXyXh8cU6Qxie7hHtyY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773168054; 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=V5YkjUUJBV1v9w6glWVAc19NSmabp+/ufD6M3HIg7xIQ9tPUgJy5EgsyEzePD9HAxwSAXlI3eLb5TtexFnzIjf2AJs2lzJaIT0uPKg/uCAG2KZDFXWryFngDUs8lQ09bBAFlW5M5qn2MOoXMuWCBdUu35regdlVW0rkKDJfSb04= 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=209.85.215.170 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-f170.google.com with SMTP id 41be03b00d2f7-c736261ee8dso3400306a12.1 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=B49so7wdywLJNiQGkrXofOHW15SwTr/ts0e5KtiQ3SvNxKTgZRHTxGU5WDiZE0u45d 9Ml9s6Jy+3xxEEBAKsJG21Q+TYG1g9IOS7dHAnWbCOejFGNYq9Fuml6liFcgc4Zyx6qm dHnzMoZ2LMSaESI3rjN+7jzIEm2C6jUrahQJpaMDp41n2TkNvwMU58aEjRcSNyfE6bRb rpdUUZjIaETCZpPMb6LJHFKfkdEfM7Tv/2oFy8RVq8NbBnnXOUf+d+gyJ+5yQDp8wgKy 10gerzVihfuyEE2vl38E84ytVTGUfYVF2jj9bjRQATO4sJ4Qiiir/Qw/axRymoXsbCXT jbew== X-Forwarded-Encrypted: i=1; AJvYcCXD0Sv3dUTnCbRpkYdXlfJmbs/1CpMPaSzk63/pgi5h3uYqSJBnU8IAY61rtjGmTmrZKeTozR1jX6azIPUJ@vger.kernel.org X-Gm-Message-State: AOJu0Yw1FhxL6y0kAB7fGsTAwn5gsTrmBnyDnvVcnAiKfhiuKN4anvms orozp3cElOKYI3leTGHOHvT95NIPr+f+WINs49/x0M1xE5X+hXMOys13 X-Gm-Gg: ATEYQzw0cwKGRxhoPILD1t7YAHapslVdZOpr8lQ1lF8c+7DEwBUzxbv2DiTxB7DccOj lFpgL6vud1k1297+M1h2h6W6kg06nNtsBJ4IuTLJI4XSBO1kVJ5Iak01M3HYXg47l+/dJ/+jB1P aK8vC662tGgXMnKqnGxZmwZzVt20jfmW3iTAdyexhroCWR/sM0bxnk8ESL+T7DOPSJYgYxeWOim 6GRrZvFq7Hy28NQsLKVo1EKnaqLaGRlxIamcxDWbtAfdyOAdodtDnyLASTgo4gHX9wx3UPWOaUn McMKmTZvWUgG/NjYTJ87w7xyMwi3vC+JKhFlQMDhP44SURsHkGk28i3rcR7K894FAEwYjGT4xHu fOkonTK6kMUYbYdueF1gWgflYiU4O8w3dTPOTdzA8ZPIG+/wWlHwfS4CbjhxgOms8ZY0aXsA0GJ AsabhCVMTwSfnFfFWZ3gu6/rUT4ipKEOal4XwgqKTjhZH9vg== 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-fsdevel@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