Date: Thu, 25 Jun 2015 14:21:14 +0300
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Maninder Singh <maninder1.s@samsung.com>
Cc: abbotti@mev.co.uk, hsweeten@visionengravers.com,
        gregkh@linuxfoundation.org, devel@driverdev.osuosl.org,
        linux-kernel@vger.kernel.org, pankaj.m@samsung.com
Subject: Re: [PATCH 1/1] staging/comedi: remove unnecessary check around
 pci_dev_put
Message-ID: <20150625112114.GB28762@mwanda>
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On Thu, Jun 25, 2015 at 04:20:26PM +0530, Maninder Singh wrote:
> pci_dev_put cehcks for NULL pointer itself,
> reported by coccinelle
> 

This patch is correct but the motivation is wrong.

The check in pci_dev_put() is like a sanity check.  There are many
functions which have a sanity check and many which do not, it is
impossible for a human to remember the complete list of each.  When we
remove explicit checks for NULL and instead rely on the sanity checks
it sometimes makes the code more subtle and difficult to read.

In this case, "pcidev" can never be NULL so the check is misleading and
makes the code more complicated.  Removing it is a good thing.  Also
the attach function does not have a NULL check so when we remove this
check we make the code more consistent.

But in other cases, if "pcidev" could be NULL then we should keep the
check so that the code is easier to read.

regards,
dan carpenter

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