linux-kernel - Re: USB: serial: Deletion of an unnecessary check before the function call "release

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Message-ID: <20141124091003.GA6875@localhost>
Date:	Mon, 24 Nov 2014 10:10:03 +0100
From:	Johan Hovold <johan@...nel.org>
To:	Julia Lawall <julia.lawall@...6.fr>
Cc:	SF Markus Elfring <elfring@...rs.sourceforge.net>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Johan Hovold <johan@...nel.org>, linux-usb@...r.kernel.org,
	LKML <linux-kernel@...r.kernel.org>,
	kernel-janitors@...r.kernel.org
Subject: Re: USB: serial: Deletion of an unnecessary check before the
 function call "release_firmware"

On Fri, Nov 21, 2014 at 06:59:00PM +0100, Julia Lawall wrote:
> On Fri, 21 Nov 2014, SF Markus Elfring wrote:
> 
> > >> diff --git a/drivers/usb/serial/mxuport.c b/drivers/usb/serial/mxuport.c
> > >> index ab1d690..3653ec1 100644
> > >> --- a/drivers/usb/serial/mxuport.c
> > >> +++ b/drivers/usb/serial/mxuport.c
> > >> @@ -1101,8 +1101,7 @@ static int mxuport_probe(struct usb_serial *serial,
> > >>  	 */
> > >>  	usb_set_serial_data(serial, (void *)id->driver_info);
> > >>  out:
> > >> -	if (fw_p)
> > >> -		release_firmware(fw_p);
> > >> +	release_firmware(fw_p);
> > >
> > > I think that the if should stay.
> >
> > I have got an other opinion.
> >
> >
> > > There were two cases on the allocation, so there should be two cases
> > > on the release.
> >
> > I find that this implementation detail does not really matter for the
> > necessity of a null pointer check directly before such a function call.
> 
> Conceptually, if it is clear 10 lines above that nothing was allocated,
> and there is a fallback to existing data (according to the comment above)
> it is strange to be releasing something.

I agree with Julia here and will not apply this one.

Thanks,
Johan
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