From mboxrd@z Thu Jan 1 00:00:00 1970 From: SF Markus Elfring Date: Mon, 01 Dec 2014 01:34:37 +0000 Subject: Re: net-PA Semi: Deletion of unnecessary checks before the function call "pci_dev_put" Message-Id: <547BC5AD.6090500@users.sourceforge.net> List-Id: References: <5307CAA2.8060406@users.sourceforge.net> <530A086E.8010901@users.sourceforge.net> <530A72AA.3000601@users.sourceforge.net> <530B5FB6.6010207@users.sourceforge.net> <530C5E18.1020800@users.sourceforge.net> <530CD2C4.4050903@users.sourceforge.net> <530CF8FF.8080600@users.sourceforge.net> <530DD06F.4090703@users.sourceforge.net> <5317A59D.4@users.sourceforge.net> <547A09B1.9090102@users.sourceforge.net> <547B579F.10709@gmx.de> In-Reply-To: <547B579F.10709@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Lino Sanfilippo , Olof Johansson , netdev@vger.kernel.org, backports@vger.kernel.org Cc: LKML , kernel-janitors@vger.kernel.org, Julia Lawall , "Luis R. Rodriguez" > I know there has been some criticism about those kind of "code > improvements" already but i would like to point out just one more thing: > > Some of those NULL pointer checks on input parameters may have been > added subsequently to functions. So there may be older kernel versions > out there in which those checks dont exists in some cases. If some of > the now "cleaned up" code is backported to such a kernel chances are > good that those missing checks are overseen. And then neither caller nor > callee is doing the NULL pointer check. I guess that the Coccinelle software can also help you in this use case. How do you think about to shield against "unwanted" or unexpected collateral evolutions with additional inline functions? I assume that a few backporters can tell you more about their corresponding software development experiences. http://www.do-not-panic.com/2014/04/automatic-linux-kernel-backporting-with-coccinelle.html Regards, Markus