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[142.162.112.119]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-5093a119602sm36658181cf.28.2026.03.12.09.54.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Mar 2026 09:54:49 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1w0jJA-00000006i8N-40X9; Thu, 12 Mar 2026 13:54:48 -0300 Date: Thu, 12 Mar 2026 13:54:48 -0300 From: Jason Gunthorpe To: James Bottomley Cc: Kuan-Wei Chiu , 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 Subject: Re: [PATCH 00/61] treewide: Use IS_ERR_OR_NULL over manual NULL check - refactor Message-ID: <20260312165448.GN1469476@ziepe.ca> References: <20260310-b4-is_err_or_null-v1-0-bd63b656022d@avm.de> <20260312125730.GI1469476@ziepe.ca> Precedence: bulk X-Mailing-List: linux-kernel@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: On Thu, Mar 12, 2026 at 11:32:37AM -0400, James Bottomley wrote: > 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: > > > > > 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. > > > > +1 > > > > 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. > 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. Lots of places also would return ENOENT, I'd argue that is easier to use.. But yes, I did use the word "suspicion" not blanket wrong :) Jason