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Thu, 29 Oct 2020 10:27:17 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 09TAQARU157091; Thu, 29 Oct 2020 10:27:17 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3020.oracle.com with ESMTP id 34cx60bs6y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 29 Oct 2020 10:27:16 +0000 Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 09TARDgg004536; Thu, 29 Oct 2020 10:27:14 GMT Received: from kadam (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 29 Oct 2020 03:27:13 -0700 Date: Thu, 29 Oct 2020 13:27:05 +0300 From: Dan Carpenter To: Miquel Raynal Subject: Re: [PATCH] mtd: nand: ecc-hamming: Clarify the logic around rp17 Message-ID: <20201029102705.GR18329@kadam> References: <20201029083847.21128-1-miquel.raynal@bootlin.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201029083847.21128-1-miquel.raynal@bootlin.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9788 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 mlxscore=0 mlxlogscore=999 suspectscore=0 bulkscore=0 malwarescore=0 spamscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010290076 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9788 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 lowpriorityscore=0 adultscore=0 malwarescore=0 spamscore=0 clxscore=1011 mlxscore=0 suspectscore=0 priorityscore=1501 impostorscore=0 bulkscore=0 phishscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2010290076 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201029_062727_247789_B27B6ED0 X-CRM114-Status: GOOD ( 23.49 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Richard Weinberger , kernel test robot , linux-mtd@lists.infradead.org, Vignesh Raghavendra , Tudor Ambarus Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Thu, Oct 29, 2020 at 09:38:47AM +0100, Miquel Raynal wrote: > This code has been written in 2008 and is fine, but in order to keep > robots happy, I think it's time to change a little bit this code just > to clarify the different possible values of eccsize_mult. Indeed, this > variable may only take the value 1 or 2 because step_size, in the case > of the software Hamming ECC engine may only be 256 or 512. Depending > on the value of eccsize_mult, an extra rp17 variable is set, or not > and triggers the following warning: > > smatch warnings: > ecc_sw_hamming_calculate() error: uninitialized symbol 'rp17'. > > As highlighted by Dan Carpenter, if the only possible values for > eccsize_mult are 1 and 2, then the code is fine, but "it's hard to > tell just from looking". > > So instead of shifting step_size, let's use a ternary condition to > assign to eccsize_mult the only two possible values and clarify the > driver's logic. > > Now that the situation is clarified for humans, set rp17 to 0 in an > else block to keep robots silent as well. Smatch will parse it correctly with just the ternary change but there might be other checkers which want the the else statement. I'm not sure. GCC doesn't seem to warn about uninitialized variables these days. regards, dan carpenter ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/