linux-kernel - Re: [PATCH] libnvdimm: remove redundant assignment to pointer 'dev'

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Message-ID: <22ac2ac7-f75f-3cd0-30d7-8cfe7605c8fb@canonical.com>
Date:   Mon, 5 Feb 2018 20:46:47 +0000
From:   Colin Ian King <colin.king@...onical.com>
To:     Dan Williams <dan.j.williams@...el.com>,
        Ross Zwisler <ross.zwisler@...ux.intel.com>
Cc:     linux-nvdimm@...ts.01.org, kernel-janitors@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] libnvdimm: remove redundant assignment to pointer 'dev'

On 05/02/18 18:44, Dan Williams wrote:
> On Mon, Feb 5, 2018 at 10:20 AM, Ross Zwisler
> <ross.zwisler@...ux.intel.com> wrote:
>> On Mon, Feb 05, 2018 at 02:08:52PM +0000, Colin King wrote:
>>> From: Colin Ian King <colin.king@...onical.com>
>>>
>>> Pointer dev is being assigned a value that is never read, it is being
>>> re-assigned the same value later on, hence the initialization is redundant
>>> and can be removed.
>>>
>>> Cleans up clang warning:
>>> drivers/nvdimm/pfn_devs.c:307:17: warning: Value stored to 'dev' during
>>> its initialization is never read
>>>
>>> Signed-off-by: Colin Ian King <colin.king@...onical.com>
>>
>> Reviewed-by: Ross Zwisler <ross.zwisler@...ux.intel.com>
>>
>> More importantly this fixes a potential NULL pointer dereference.  nd_pfn
>> is checked for NULL a few lines down, but we would have crashed here trying to
>> get nd_pfn->dev.
>>
> 
> No we wouldn't crash. We're just calculating the address, not
> de-referencing a NULL pointer.

Indeed, it's just a warning clean up. Nothing more.

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