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Subject: Re: [PATCH v3 bpf-next 03/10] bpf: introduce per-cpu cgroup local
 storage
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>,
        Roman Gushchin <guro@fb.com>
Cc:     netdev@vger.kernel.org, Song Liu <songliubraving@fb.com>,
        linux-kernel@vger.kernel.org, kernel-team@fb.com,
        Alexei Starovoitov <ast@kernel.org>
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From:   Daniel Borkmann <daniel@iogearbox.net>
Message-ID: <21a7ecfb-c7cd-d7aa-01d1-4e055e410817@iogearbox.net>
Date:   Fri, 28 Sep 2018 14:03:29 +0200
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On 09/28/2018 12:25 PM, Alexei Starovoitov wrote:
> On Fri, Sep 28, 2018 at 11:03:03AM +0100, Roman Gushchin wrote:
>>>> +
>>>> +	if (unlikely(map_flags & BPF_EXIST))
>>>> +		return -EINVAL;
>>>
>>> that should have been BPF_NOEXIST ?
>>
>> Yeah, or maybe even better s/&/!= ?
>> It's probably better to require BPF_EXIST flag to update a cgroup storage?
>> Agree? If so, let me fix this for both shared and per-cpu versions in
>> a follow-up patch.
> 
> I think BPF_ANY is technically valid too.
> If we were to require strict BPF_EXIST only, we'd need to fix stable too.
> I'm fine with both (BPF_EXIST only and BPF_ANY|BPF_EXIST).
> Daniel, what do you think?

I'm okay with either option, both seem plausible.