From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f182.google.com (mail-pf1-f182.google.com [209.85.210.182]) (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 69599DF5D for ; Wed, 6 Sep 2023 13:36:54 +0000 (UTC) Received: by mail-pf1-f182.google.com with SMTP id d2e1a72fcca58-68bed2c786eso2580577b3a.0 for ; Wed, 06 Sep 2023 06:36:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1694007413; x=1694612213; darn=lists.linux.dev; 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=Td6a6sw5kxMExUrt1cEVr4QfSz/8/zuHKWsclB1jWMA=; b=AF6rbkdb8XtdGHicDtXaMgpjnKaOaKht4eAXBPAA8vE0IcmcYRvsGh+5I2qFFAdiIX x4cSQyZXWyf5f5kzpzAWB31Bb0xCoW2l597CzgDemZe69g0p12k89jBvT2cNS4mbpmEk FnAhnqOPZaAKSDK/9d1RWzF4/AtF9s1i2/TqMeFdgppuOenMfqiEQK+FUYKpJCkgcf+E VuaAgV6gl/ivYjOhnYPalKsLdyxUumw3YGlx6343X5XSZLEOGHzQkRZ5I8WTFjN69yJ5 TtwRF7QPEiCkDRirvENo87hA8VO6RNneSdOO3UQhOlTAQs//76Vbk9CVmpOcD966CzMd 2YEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1694007413; x=1694612213; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Td6a6sw5kxMExUrt1cEVr4QfSz/8/zuHKWsclB1jWMA=; b=UFa7XFWbnfy2Bg32NajhMdbMX37Jbniyhh7zLEWz+rEGymTx6uQcDHjIT3Pdsvzjcq WrlpeUhz7B5IzkDuciy9SeIEXUzMKZHkMwiOeycngaZQumcJmB+REu7Wsz3zb/iCMwW6 LtKbgnrjll4Gan5hL1tdMHI+8LJazEncset2+mVuL6oXNKeBWQxS4GXImbfT+vlp8iVZ pbmVD/apRNZQRSso+obKRhb7KceWwN1+xGFiXA6UYqeDPt1zRgz9DFiadaSvfd+Ho8oD DX5t9gOHq4WraE4DvPByuINWMsfPehxsk5kd0Y6vB2j6YksXhetlMWZRbSsArqONCkRx 51ng== X-Gm-Message-State: AOJu0Yx4dmY/+Zqx+t7lnUHYFT+GS3em6TUx7mjx9LCqO5BQtsO4q1RN B8nj64sobOtSkrkZPPQVglXNFA== X-Google-Smtp-Source: AGHT+IGOwRHPmAKNRaGsD/hGYssr/5Y0BJzqOelNvybA7jZN/WxhNoLttPYaPUwO81J4iLj5RhHYKA== X-Received: by 2002:a05:6a00:2e84:b0:68a:52ec:3d36 with SMTP id fd4-20020a056a002e8400b0068a52ec3d36mr17143606pfb.31.1694007413553; Wed, 06 Sep 2023 06:36:53 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-142-68-25-194.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.68.25.194]) by smtp.gmail.com with ESMTPSA id g20-20020a62e314000000b00688214cff65sm10826298pfh.44.2023.09.06.06.36.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 06 Sep 2023 06:36:52 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1qdsiB-000yIl-HZ; Wed, 06 Sep 2023 10:36:51 -0300 Date: Wed, 6 Sep 2023 10:36:51 -0300 From: Jason Gunthorpe To: Baolu Lu Cc: Jinjie Ruan , linux-tegra@vger.kernel.org, iommu@lists.linux.dev, Thierry Reding , Krishna Reddy , Joerg Roedel , Will Deacon , Robin Murphy , Jonathan Hunter Subject: Re: [PATCH] iommu/tegra-smmu: Fix the NULL vs IS_ERR() bug for debugfs_create_dir() Message-ID: References: <20230831123846.3137304-1-ruanjinjie@huawei.com> <8830ecd1-f7a3-a708-66b1-2d9698d0d477@linux.intel.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8830ecd1-f7a3-a708-66b1-2d9698d0d477@linux.intel.com> On Fri, Sep 01, 2023 at 11:05:48AM +0800, Baolu Lu wrote: > On 2023/8/31 20:38, Jinjie Ruan wrote: > > The debugfs_create_dir() function returns error pointers. > > It never returns NULL. So use IS_ERR() to check it. > > > > Fixes: d1313e7896e9 ("iommu/tegra-smmu: Add debugfs support") > > Signed-off-by: Jinjie Ruan > > --- > > drivers/iommu/tegra-smmu.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c > > index e445f80d0226..cd1d80c4c673 100644 > > --- a/drivers/iommu/tegra-smmu.c > > +++ b/drivers/iommu/tegra-smmu.c > > @@ -1056,7 +1056,7 @@ DEFINE_SHOW_ATTRIBUTE(tegra_smmu_clients); > > static void tegra_smmu_debugfs_init(struct tegra_smmu *smmu) > > { > > smmu->debugfs = debugfs_create_dir("smmu", NULL); > > - if (!smmu->debugfs) > > + if (IS_ERR(smmu->debugfs)) > > return; > > There is no need to check the return value of debugfs_create_dir(). This > change cannot fix anything as far as I can see. Just remove the > check. Right Jason