netdev - Re: [PATCH bpf-next v7] samples: bpf: add max_pckt_size option at xdp_adjust

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Date:   Mon, 7 Oct 2019 20:24:19 -0700
From:   Alexei Starovoitov <alexei.starovoitov@...il.com>
To:     "Daniel T. Lee" <danieltimlee@...il.com>
Cc:     Yonghong Song <yhs@...com>, Song Liu <liu.song.a23@...il.com>,
        Andrii Nakryiko <andrii.nakryiko@...il.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Alexei Starovoitov <ast@...nel.org>, bpf <bpf@...r.kernel.org>,
        Network Development <netdev@...r.kernel.org>
Subject: Re: [PATCH bpf-next v7] samples: bpf: add max_pckt_size option at xdp_adjust_tail

On Mon, Oct 7, 2019 at 10:21 AM Daniel T. Lee <danieltimlee@...il.com> wrote:
>
> Currently, at xdp_adjust_tail_kern.c, MAX_PCKT_SIZE is limited
> to 600. To make this size flexible, static global variable
> 'max_pcktsz' is added.
>
> By updating new packet size from the user space, xdp_adjust_tail_kern.o
> will use this value as a new max packet size.
>
> This static global variable can be accesible from .data section with
> bpf_object__find_map* from user space, since it is considered as
> internal map (accessible with .bss/.data/.rodata suffix).
>
> If no '-P <MAX_PCKT_SIZE>' option is used, the size of maximum packet
> will be 600 as a default.
>
> For clarity, change the helper to fetch map from 'bpf_map__next'
> to 'bpf_object__find_map_fd_by_name'. Also, changed the way to
> test prog_fd, map_fd from '!= 0' to '< 0', since fd could be 0
> when stdin is closed.
>
> Signed-off-by: Daniel T. Lee <danieltimlee@...il.com>
>
> ---
> Changes in v6:
>     - Remove redundant error message

Applied.
Please keep Acks if you're only doing minor tweaks between versions.