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

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Date:	Fri, 21 Nov 2014 18:59:00 +0100 (CET)
From:	Julia Lawall <julia.lawall@...6.fr>
To:	SF Markus Elfring <elfring@...rs.sourceforge.net>
cc:	Julia Lawall <julia.lawall@...6.fr>,
	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, 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.

julia
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