netdev - Re: [PATCH v2 net-next 1/5] l2tp: fix switch default error handling in l2tp_nl_cmd_session

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Date:   Mon, 15 Jan 2018 22:00:47 +0000
From:   James Chapman <jchapman@...alix.com>
To:     Lorenzo Bianconi <lorenzo.bianconi@...hat.com>
Cc:     Guillaume Nault <g.nault@...halink.fr>,
        "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [PATCH v2 net-next 1/5] l2tp: fix switch default error handling
 in l2tp_nl_cmd_session_create()

On 15 January 2018 at 21:18, Lorenzo Bianconi
<lorenzo.bianconi@...hat.com> wrote:
>> On Sun, Jan 14, 2018 at 03:50:54PM +0100, Lorenzo Bianconi wrote:
>>> Although this issue is harmless since that code path is protected by the
>>> check on l2tp_nl_cmd_ops[]/l2tp_nl_cmd_ops[]->session_create(), fix error
>>> handling for L2TP_PWTYPE_IP/default case in l2tp_nl_cmd_session_create()
>>>
>>> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@...hat.com>
>>> ---
>>>  net/l2tp/l2tp_netlink.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
>>> index e1ca29f79821..48b5bf30ec50 100644
>>> --- a/net/l2tp/l2tp_netlink.c
>>> +++ b/net/l2tp/l2tp_netlink.c
>>> @@ -635,7 +635,7 @@ static int l2tp_nl_cmd_session_create(struct sk_buff *skb, struct genl_info *inf
>>>       case L2TP_PWTYPE_IP:
>>>       default:
>>>               ret = -EPROTONOSUPPORT;
>>> -             break;
>>> +             goto out_tunnel;
>>>       }
>>>
>> Not sure if this change is really worthwhile. As you noted, this is
>> unreachable code. And this switch should better be removed entirely:
>> it doesn't do anything for supported pseudo-wires.
>>
>> And if PWTYPE_ETH_VLAN were to be implemented, it should perform its
>> configuration consistency checking in its own PW specific code, not in
>> the genl handler.
>>
>
> Personally I would prefer to not remove some code that could be useful
> for a future implementation, but just fix it if it presents issues to
> address.
> Anyway we can simply drop this patch from the series and I can send a
> new one to remove the switch entirely.
>
> @James what do you think?

Keep the patch series focused. If you read the patch series as a set,
this patch stands out as not fitting the purpose of the series. I
agree with Guillaume.

>
> Regards,
> Lorenzo
>
>> Anyway, removing this switch isn't the purpose of this series, so I
>> think you can drop this patch.

I agree.