linux-kernel - Re: [PATCH] media: atomisp: remove compat

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Date:   Mon, 24 May 2021 18:18:29 +0300
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Arnd Bergmann <arnd@...nel.org>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        Hans Verkuil <hverkuil@...all.nl>,
        Christoph Hellwig <hch@....de>,
        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] media: atomisp: remove compat_ioctl32 code

Hi Arnd,

On Sun, May 16, 2021 at 10:47:43PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> This is one of the last remaining users of compat_alloc_user_space()
> and copy_in_user(), which are in the process of getting removed.
> 
> As of commit 57e6b6f2303e ("media: atomisp_fops.c: disable
> atomisp_compat_ioctl32"), nothing in this file is actually getting used
> as the only reference has been stubbed out.

This patch was made redundant by another one that fixed the bug. But I
guess you're right in the sense that no-one could have used this because of
the patch that disabled it.

So:

Acked-by: Sakari Ailus <sakari.ailus@...ux.intel.com>

But:

> diff --git a/drivers/staging/media/atomisp/pci/atomisp_fops.c b/drivers/staging/media/atomisp/pci/atomisp_fops.c
> index f1e6b2597853..e383e17c5072 100644
> --- a/drivers/staging/media/atomisp/pci/atomisp_fops.c
> +++ b/drivers/staging/media/atomisp/pci/atomisp_fops.c
> @@ -1283,7 +1283,8 @@ const struct v4l2_file_operations atomisp_fops = {
>  	.unlocked_ioctl = video_ioctl2,
>  #ifdef CONFIG_COMPAT
>  	/*
> -	 * There are problems with this code. Disable this for now.
> +	 * this was removed because of bugs, the interface
> +	 * needs to be made safe for compat tasks instead.
>  	.compat_ioctl32 = atomisp_compat_ioctl32,

I think the comment could go, too.

>  	 */
>  #endif
> @@ -1297,10 +1298,7 @@ const struct v4l2_file_operations atomisp_file_fops = {
>  	.mmap = atomisp_file_mmap,
>  	.unlocked_ioctl = video_ioctl2,
>  #ifdef CONFIG_COMPAT
> -	/*
> -	 * There are problems with this code. Disable this for now.
> -	.compat_ioctl32 = atomisp_compat_ioctl32,
> -	 */
> +	/* .compat_ioctl32 = atomisp_compat_ioctl32, */

Thie one, too.

>  #endif
>  	.poll = atomisp_poll,
>  };

-- 
Kind  regards,

Sakari Ailus