netdev - Re: [PATCH bpf-next 0/2] bpf: allocate extra memory for setsockopt hook buffer

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Date:   Thu, 1 Aug 2019 14:11:35 -0700
From:   Stanislav Fomichev <sdf@...ichev.me>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc:     Stanislav Fomichev <sdf@...gle.com>, netdev@...r.kernel.org,
        bpf@...r.kernel.org, davem@...emloft.net, ast@...nel.org,
        daniel@...earbox.net
Subject: Re: [PATCH bpf-next 0/2] bpf: allocate extra memory for setsockopt
 hook buffer

On 08/01, Alexei Starovoitov wrote:
> On Mon, Jul 29, 2019 at 02:51:09PM -0700, Stanislav Fomichev wrote:
> > Current setsockopt hook is limited to the size of the buffer that
> > user had supplied. Since we always allocate memory and copy the value
> > into kernel space, allocate just a little bit more in case BPF
> > program needs to override input data with a larger value.
> > 
> > The canonical example is TCP_CONGESTION socket option where
> > input buffer is a string and if user calls it with a short string,
> > BPF program has no way of extending it.
> > 
> > The tests are extended with TCP_CONGESTION use case.
> 
> Applied, Thanks
> 
> Please consider integrating test_sockopt* into test_progs.
Sure, will take a look. I think I didn't do it initially
because these tests create/move to cgroups and test_progs
do simple tests with BPF_PROG_TEST_RUN.