linux-kernel - Re: [PATCH v3 4/8] media: subdev: remove VIDIOC_DQEVENT

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Message-ID: <YMeLlvALJ5nJbQGg@pendragon.ideasonboard.com>
Date:   Mon, 14 Jun 2021 20:02:14 +0300
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Arnd Bergmann <arnd@...nel.org>
Cc:     Hans Verkuil <hverkuil-cisco@...all.nl>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Arnd Bergmann <arnd@...db.de>,
        "Lad, Prabhakar" <prabhakar.csengg@...il.com>,
        Eduardo Valentin <edubezval@...il.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Vaibhav Gupta <vaibhavgupta40@...il.com>,
        Liu Shixin <liushixin2@...wei.com>,
        Jacopo Mondi <jacopo+renesas@...ndi.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-staging@...ts.linux.dev
Subject: Re: [PATCH v3 4/8] media: subdev: remove VIDIOC_DQEVENT_TIME32
 handling

Hi Arnd,

Thank you for the patch.

On Mon, Jun 14, 2021 at 12:34:05PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> Converting the VIDIOC_DQEVENT_TIME32/VIDIOC_DQEVENT32/
> VIDIOC_DQEVENT32_TIME32 arguments to the canonical form is done in common
> code, but for some reason I ended up adding another conversion helper to
> subdev_do_ioctl() as well. I must have concluded that this does not go
> through the common conversion, but it has done that since the ioctl
> handler was first added.
> 
> I assume this one is harmless as there should be no way to arrive here
> from user space, but since it is dead code, it should just get removed.

If I'm not mistaken, this could be reached when
!CONFIG_COMPAT_32BIT_TIME, can't it ? Still, there's no need for this
code in that case, so it seems fine to me.

> Fixes: 1a6c0b36dd19 ("media: v4l2-core: fix VIDIOC_DQEVENT for time64 ABI")
> Signed-off-by: Arnd Bergmann <arnd@...db.de>

With an updated commit message if the above is correct,

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 24 ------------------------
>  1 file changed, 24 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 956dafab43d4..bf3aa9252458 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -428,30 +428,6 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>  
>  		return v4l2_event_dequeue(vfh, arg, file->f_flags & O_NONBLOCK);
>  
> -	case VIDIOC_DQEVENT_TIME32: {
> -		struct v4l2_event_time32 *ev32 = arg;
> -		struct v4l2_event ev = { };
> -
> -		if (!(sd->flags & V4L2_SUBDEV_FL_HAS_EVENTS))
> -			return -ENOIOCTLCMD;
> -
> -		rval = v4l2_event_dequeue(vfh, &ev, file->f_flags & O_NONBLOCK);
> -
> -		*ev32 = (struct v4l2_event_time32) {
> -			.type		= ev.type,
> -			.pending	= ev.pending,
> -			.sequence	= ev.sequence,
> -			.timestamp.tv_sec  = ev.timestamp.tv_sec,
> -			.timestamp.tv_nsec = ev.timestamp.tv_nsec,
> -			.id		= ev.id,
> -		};
> -
> -		memcpy(&ev32->u, &ev.u, sizeof(ev.u));
> -		memcpy(&ev32->reserved, &ev.reserved, sizeof(ev.reserved));
> -
> -		return rval;
> -	}
> -
>  	case VIDIOC_SUBSCRIBE_EVENT:
>  		return v4l2_subdev_call(sd, core, subscribe_event, vfh, arg);
>  

-- 
Regards,

Laurent Pinchart