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s=arc-20220608; d=hostedemail.com; t=1773667833; a=rsa-sha256; cv=none; b=GFOXTfP2o+1OwOy/gHsFhK14yCxFoEHLFo3aoG5lFkqI0nFwjSSXvKAnU9cAqgW7Y7Hc3x t9itvdytWaMINCmgi2dY+UTD07Gx/k3i9y6jEKY+/KQ4kOW/ihaBqAbdcrd4FE8DoBZiDZ /Iu9EQ8IjW68AO/fYakCiz5k3iFsoFo= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf22.hostedemail.com: domain of robin.murphy@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=robin.murphy@arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 357291477; Mon, 16 Mar 2026 06:30:25 -0700 (PDT) Received: from [10.57.61.116] (unknown [10.57.61.116]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9D4953F778; Mon, 16 Mar 2026 06:30:22 -0700 (PDT) Message-ID: <2c7466f5-d952-4356-9b55-9d2ebb3471f2@arm.com> Date: Mon, 16 Mar 2026 13:30:19 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 50/61] iommu: Prefer IS_ERR_OR_NULL over manual NULL check To: 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 Cc: Joerg Roedel , Will Deacon References: <20260310-b4-is_err_or_null-v1-0-bd63b656022d@avm.de> <20260310-b4-is_err_or_null-v1-50-bd63b656022d@avm.de> From: Robin Murphy Content-Language: en-GB In-Reply-To: <20260310-b4-is_err_or_null-v1-50-bd63b656022d@avm.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: B606EC000A X-Stat-Signature: mts7be8jq8y4by7x3w69hztc6zk4snqx X-Rspam-User: X-HE-Tag: 1773667832-858558 X-HE-Meta: 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 6bWHO3Yl jFL+SzfMI5Z/Bjpm7/OqgMF/cJvQDH8GbicfsVWUOVdzonYweuzmo6hXni6UOt/ewbxKwj0gUSvxthTQMVwsV6Fym7DfrDjwQEwmgQkZeR/J9GwZ6AIZ7jYdcCqhqwnXzGrOXoNDOjRp6/7O5aP3OCzMmp0flWPi1grUz2pS92QeNMeT4aDP2hSoNnlt5p99+viZgaQ2ucCDORZvKEnpwsExU441jyPbKDVXaG9yBzJDYyW7evGuBlTKGYshMQLduFQTTw1jYOSmPu4wulIMuVivvRwdji+mzSIOM3cjacT6fCCZzDNR30ff4zDp3m+r7SSUWi1SmV/HS83PKjoVOoEX4ksjKQvMiHHwtL9uEZeQhXfIo7FgTUBQC6g== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2026-03-10 11:49 am, Philipp Hahn wrote: > Prefer using IS_ERR_OR_NULL() over using IS_ERR() and a manual NULL > check. AFAICS it doesn't look possible for the argument to be anything other than valid at both callsites, so *both* conditions here seem in fact to be entirely redundant. > Change generated with coccinelle. Please use coccinelle responsibly. Mechanical changes are great for scripted API updates, but for cleanup, whilst it's ideal for *finding* areas of code that are worth looking at, the code then wants actually looking at, in its whole context, because meaningful cleanup often goes deeper than trivial replacement. In particular, anywhere IS_ERR_OR_NULL() is genuinely relevant is usually a sign of bad interface design, so if you're looking at this then you really should be looking first and foremost to remove any checks that are already unnecessary, and for the remainder, to see if the thing being checked can be improved to not mix the two different styles. That would be constructive and (usually) welcome cleanup. Simply churning a bunch of code with this ugly macro that's arguably less readable than what it replaces, not so much. Thanks, Robin. > To: Joerg Roedel > To: Will Deacon > To: Robin Murphy > Cc: iommu@lists.linux.dev > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Philipp Hahn > --- > drivers/iommu/omap-iommu.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c > index 8231d7d6bb6a9202025643639a6b28e6faa84659..500a42b57a997696ff37c76f028a717ab71d01f9 100644 > --- a/drivers/iommu/omap-iommu.c > +++ b/drivers/iommu/omap-iommu.c > @@ -881,7 +881,7 @@ static int omap_iommu_attach(struct omap_iommu *obj, u32 *iopgd) > **/ > static void omap_iommu_detach(struct omap_iommu *obj) > { > - if (!obj || IS_ERR(obj)) > + if (IS_ERR_OR_NULL(obj)) > return; > > spin_lock(&obj->iommu_lock); >