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Wed, 11 Nov 2020 09:28:55 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3030.oracle.com with ESMTP id 34p55pqrs2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 11 Nov 2020 09:28:55 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 0AB9Sllj029705; Wed, 11 Nov 2020 09:28:47 GMT Received: from kadam (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 11 Nov 2020 01:28:47 -0800 Date: Wed, 11 Nov 2020 12:28:32 +0300 From: Dan Carpenter To: Thierry Reding Cc: Dmitry Osipenko , Peter Chen , Ulf Hansson , Liam Girdwood , dri-devel@lists.freedesktop.org, Adrian Hunter , devicetree@vger.kernel.org, Lee Jones , Marek Szyprowski , devel@driverdev.osuosl.org, linux-samsung-soc@vger.kernel.org, Nicolas Chauvet , Krzysztof Kozlowski , Jonathan Hunter , Alan Stern , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , linux-media@vger.kernel.org, linux-pwm@vger.kernel.org, Rob Herring , linux-tegra@vger.kernel.org, Mauro Carvalho Chehab , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Mark Brown , Peter Geis Subject: Re: [PATCH v1 11/30] drm/tegra: dc: Support OPP and SoC core voltage scaling Message-ID: <20201111092832.GI29398@kadam> References: <20201104234427.26477-1-digetx@gmail.com> <20201104234427.26477-12-digetx@gmail.com> <20201110202945.GF2375022@ulmo> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201110202945.GF2375022@ulmo> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9801 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 spamscore=0 phishscore=0 mlxlogscore=999 mlxscore=0 malwarescore=0 bulkscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011110051 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9801 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 mlxlogscore=999 mlxscore=0 malwarescore=0 suspectscore=0 lowpriorityscore=0 adultscore=0 phishscore=0 priorityscore=1501 spamscore=0 impostorscore=0 clxscore=1011 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011110051 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Tue, Nov 10, 2020 at 09:29:45PM +0100, Thierry Reding wrote: > > + err = dev_pm_opp_of_add_table(dc->dev); > > + if (err) { > > + dev_err(dc->dev, "failed to add OPP table: %d\n", err); > > + goto put_hw; > > + } > > + > > + err = devm_add_action(dc->dev, tegra_dc_deinit_opp_table, dc); > > + if (err) > > + goto remove_table; > > Do these functions return positive values? If not, I'd prefer if this > check was more explicit (i.e. err < 0) for consistency with the rest of > this code. > Isn't it the other way around? It's only when the check is explicitly for "if (ret < 0)" that we have to wonder about positives. If the codes says "if (ret)" then we know that it doesn't return positive values and every non-zero is an error. In the kernel "if (ret)" is way more popular than "if (ret < 0)": $ git grep 'if (\(ret\|rc\|err\))' | wc -l 92927 $ git grep 'if (\(ret\|rc\|err\) < 0)' | wc -l 36577 And some of those are places where "ret" can be positive so we are forced to use the "if (ret < 0)" format. Checking for "if (ret)" is easier from a static analysis perspective. If it's one style is used consistently then they're the same but when there is a mismatch the "if (ret < 0) " will trigger a false positive and the "if (ret) " will not. int var; ret = frob(&var); if (ret < 0) return ret; Smatch thinks positive returns are not handled so it complains that "var can be uninitialized". regards, dan carpenter