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

[Cong Wang <xiyou.wangcong@gmail.com>]

On Tue, Apr 26, 2022 at 2:12 AM Jakub Sitnicki <jakub@cloudflare.com> wrote:
>
> 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?

Yeah, I will add some comments to explain this in V2.

Thanks.