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 23:07:27 +0100
From:   Lorenzo Bianconi <lorenzo.bianconi@...hat.com>
To:     James Chapman <jchapman@...alix.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.
>

Ok, fine. What about the fix? Do you prefer to remove the switch or just fix it?

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