Re: [RFC PATCH 2/9] ntsync: Reserve a minor device number and ioctl range. - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Elizabeth Figura <zfigura@codeweavers.com>
Cc: "Arnd Bergmann" <arnd@arndb.de>,
	linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	wine-devel@winehq.org, "André Almeida" <andrealmeid@igalia.com>,
	"Wolfram Sang" <wsa@kernel.org>,
	"Arkadiusz Hiler" <ahiler@codeweavers.com>,
	"Peter Zijlstra" <peterz@infradead.org>
Subject: Re: [RFC PATCH 2/9] ntsync: Reserve a minor device number and ioctl range.
Date: Tue, 23 Jan 2024 16:54:02 -0800	[thread overview]
Message-ID: <2024012356-dove-duke-f7f6@gregkh> (raw)
In-Reply-To: <20240124004028.16826-3-zfigura@codeweavers.com>

On Tue, Jan 23, 2024 at 06:40:21PM -0600, Elizabeth Figura wrote:
> Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
> ---

Note, we can't take patches without any changelog text, and you don't
want us to :)

>  Documentation/admin-guide/devices.txt              | 3 ++-
>  Documentation/userspace-api/ioctl/ioctl-number.rst | 2 ++
>  drivers/misc/ntsync.c                              | 3 ++-
>  include/linux/miscdevice.h                         | 1 +
>  4 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/admin-guide/devices.txt b/Documentation/admin-guide/devices.txt
> index 94c98be1329a..041404397ee5 100644
> --- a/Documentation/admin-guide/devices.txt
> +++ b/Documentation/admin-guide/devices.txt
> @@ -376,8 +376,9 @@
>  		240 = /dev/userio	Serio driver testing device
>  		241 = /dev/vhost-vsock	Host kernel driver for virtio vsock
>  		242 = /dev/rfkill	Turning off radio transmissions (rfkill)
> +		243 = /dev/ntsync	NT synchronization primitive device
>  
> -		243-254			Reserved for local use
> +		244-254			Reserved for local use

Why do you need a fixed minor number?  Can't your userspace handle
dynamic numbers?  What systems require a static value?

thanks,

greg k-h