Re: [Patch bpf-next v1 1/4] tcp: introduce tcp_read_skb()

[Jakub Sitnicki <jakub@cloudflare.com>]

On Sun, Apr 10, 2022 at 09:10 AM -07, Cong Wang wrote:
> From: Cong Wang <cong.wang@bytedance.com>
>
> This patch inroduces tcp_read_skb() based on tcp_read_sock(),
> a preparation for the next patch which actually introduces
> a new sock ops.
>
> TCP is special here, because it has tcp_read_sock() which is
> mainly used by splice(). tcp_read_sock() supports partial read
> and arbitrary offset, neither of them is needed for sockmap.
>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: John Fastabend <john.fastabend@gmail.com>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Jakub Sitnicki <jakub@cloudflare.com>
> Signed-off-by: Cong Wang <cong.wang@bytedance.com>
> ---
>  include/net/tcp.h |  2 ++
>  net/ipv4/tcp.c    | 72 +++++++++++++++++++++++++++++++++++++++++------
>  2 files changed, 66 insertions(+), 8 deletions(-)
>
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index 6d50a662bf89..f0d4ce6855e1 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -667,6 +667,8 @@ void tcp_get_info(struct sock *, struct tcp_info *);
>  /* Read 'sendfile()'-style from a TCP socket */
>  int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
>  		  sk_read_actor_t recv_actor);
> +int tcp_read_skb(struct sock *sk, read_descriptor_t *desc,
> +		 sk_read_actor_t recv_actor);

Do you think it would be worth adding docs for the newly added function?
Why it exists and how is it different from the tcp_read_sock which has
the same interface?

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