linux-kernel - Re: [PATCH] VIDEO: ivtvfb, remove unneeded NULL test

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Date:	Sun, 04 Jul 2010 09:24:29 +0200
From:	Jiri Slaby <jslaby@...e.cz>
To:	Andy Walls <awalls@...metrocast.net>
CC:	mchehab@...radead.org, linux-kernel@...r.kernel.org,
	Tejun Heo <tj@...nel.org>,
	Ian Armstrong <ian@...mst.demon.co.uk>,
	ivtv-devel@...vdriver.org, linux-media@...r.kernel.org
Subject: Re: [PATCH] VIDEO: ivtvfb, remove unneeded NULL test

On 07/04/2010 06:11 AM, Andy Walls wrote:
> You missed an identical instance of the useless test 10 lines prior in
> ivtvfb_callback_init(). :)

Ah, thank you for pointing out. Find my comment below.

> --- a/drivers/media/video/ivtv/ivtvfb.c
> +++ b/drivers/media/video/ivtv/ivtvfb.c
> @@ -1201,9 +1201,14 @@ static int ivtvfb_init_card(struct ivtv *itv)
>  static int __init ivtvfb_callback_init(struct device *dev, void *p)
>  {
>         struct v4l2_device *v4l2_dev = dev_get_drvdata(dev);
> -       struct ivtv *itv = container_of(v4l2_dev, struct ivtv, v4l2_dev);
> +       struct ivtv *itv;
>  
> -       if (itv && (itv->v4l2_cap & V4L2_CAP_VIDEO_OUTPUT)) {
> +       if (v4l2_dev == NULL)
> +               return 0;
> +
> +       itv = container_of(v4l2_dev, struct ivtv, v4l2_dev);
> +
> +       if (itv->v4l2_cap & V4L2_CAP_VIDEO_OUTPUT) {
>                 if (ivtvfb_init_card(itv) == 0) {
>                         IVTVFB_INFO("Framebuffer registered on %s\n",
>                                         itv->v4l2_dev.name);
> @@ -1216,10 +1221,16 @@ static int __init ivtvfb_callback_init(struct device *de
>  static int ivtvfb_callback_cleanup(struct device *dev, void *p)
>  {
>         struct v4l2_device *v4l2_dev = dev_get_drvdata(dev);
> -       struct ivtv *itv = container_of(v4l2_dev, struct ivtv, v4l2_dev);
> -       struct osd_info *oi = itv->osd_info;
> +       struct ivtv *itv;
> +       struct osd_info *oi;
> +
> +       if (v4l2_dev == NULL)
> +               return 0;

>From my POV I NACK this. Given that it never triggered and drvdata are
set in v4l2_device_register called from ivtv_probe I can't see how
v4l2_dev be NULL. Could you elaborate?

-- 
js
suse labs
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