Re: [PATCH net-next v1] net/core: Replace driver version to be kernel version

From: Florian Fainelli <f.fainelli@gmail.com>
To: Leon Romanovsky <leon@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Michal Kubecek <mkubecek@suse.cz>
Cc: Leon Romanovsky <leonro@mellanox.com>,
	Michal Kalderon <michal.kalderon@marvell.com>,
	linux-netdev <netdev@vger.kernel.org>,
	RDMA mailing list <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH net-next v1] net/core: Replace driver version to be kernel version
Date: Sat, 25 Jan 2020 08:55:01 -0800	[thread overview]
Message-ID: <b0f73391-d7f5-1efe-2927-bed02668f8c5@gmail.com> (raw)
In-Reply-To: <20200125161401.40683-1-leon@kernel.org>

On 1/25/2020 8:14 AM, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@mellanox.com>
> 
> In order to stop useless driver version bumps and unify output
> presented by ethtool -i, let's overwrite the version string.
> 
> Before this change:
> [leonro@erver ~]$ ethtool -i eth0
> driver: virtio_net
> version: 1.0.0
> After this change:
> [leonro@server ~]$ ethtool -i eth0
> driver: virtio_net
> version: 5.5.0-rc6+
> 
> Signed-off-by: Leon Romanovsky <leonro@mellanox.com>> ---
>  Changelog:
>  v1: Resend per-Dave's request
>      https://lore.kernel.org/linux-rdma/20200125.101311.1924780619716720495.davem@davemloft.net
>      No changes at all and applied cleanly on top of "3333e50b64fe Merge branch 'mlxsw-Offload-TBF'"
>  v0: https://lore.kernel.org/linux-rdma/20200123130541.30473-1-leon@kernel.org

There does not appear to be any explanation why we think this is a good
idea for *all* drivers, and not just the ones that are purely virtual?

Are you not concerned that this is ABI and that specific userland may be
relying on a specific info format and we could now be breaking their
version checks? I do not disagree that the version is not particularly
useful for in-tree kernel, but this is ABI, and breaking user-space is
usually a source of support questions.

> ---
>  net/ethtool/ioctl.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
> index 182bffbffa78..a403decacb6d 100644
> --- a/net/ethtool/ioctl.c
> +++ b/net/ethtool/ioctl.c
> @@ -17,6 +17,7 @@
>  #include <linux/phy.h>
>  #include <linux/bitops.h>
>  #include <linux/uaccess.h>
> +#include <linux/vermagic.h>
>  #include <linux/vmalloc.h>
>  #include <linux/sfp.h>
>  #include <linux/slab.h>
> @@ -666,6 +667,8 @@ static noinline_for_stack int ethtool_get_drvinfo(struct net_device *dev,
>  		return -EOPNOTSUPP;
>  	}
> 
> +	strlcpy(info.version, UTS_RELEASE, sizeof(info.version));
> +
>  	/*
>  	 * this method of obtaining string set info is deprecated;
>  	 * Use ETHTOOL_GSSET_INFO instead.
> --
> 2.24.1
> 

-- 
Florian