netdev - Re: [PATCH net-next] bpf: netdev is never null in __dev_map

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Message-ID: <599E8FA9.4000804@iogearbox.net>
Date:   Thu, 24 Aug 2017 10:34:49 +0200
From:   Daniel Borkmann <daniel@...earbox.net>
To:     John Fastabend <john.fastabend@...il.com>,
        Alexei Starovoitov <ast@...com>, davem@...emloft.net
CC:     netdev@...r.kernel.org
Subject: Re: [PATCH net-next] bpf: netdev is never null in __dev_map_flush

On 08/24/2017 05:10 AM, John Fastabend wrote:
> On 08/23/2017 06:25 PM, Alexei Starovoitov wrote:
>> On 8/23/17 6:20 PM, Daniel Borkmann wrote:
>>> No need to test for it in fast-path, every dev in bpf_dtab_netdev
>>> is guaranteed to be non-NULL, otherwise dev_map_update_elem() will
>>> fail in the first place.
>>>
>>> Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
>>
>> wow. interesting. I'm surprised you see a difference from
>> such micro-optimization.
>> Acked-by: Alexei Starovoitov <ast@...nel.org>
>
> Thanks for the clean up, I was a bit over paranoid here as well. Is
> this actually noticeable in pps benchmark or just making the code
> cleaner? Just curious.

No, just from going over the code wondering why it could be
null here but not elsewhere.