Re: [PATCH v2] net: tcp: fixes commit 98aaa913b4ed ("tcp: Extend SOF_TIMESTAMPING_RX_SOFTWARE to TCP recvmsg")

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

On Thu, May 7, 2020 at 9:18 PM Kelly Littlepage <kelly@onechronos.com> wrote:
>
> The stated intent of the original commit is to is to "return the timestamp
> corresponding to the highest sequence number data returned." The current
> implementation returns the timestamp for the last byte of the last fully
> read skb, which is not necessarily the last byte in the recv buffer. This
> patch converts behavior to the original definition, and to the behavior of
> the previous draft versions of commit 98aaa913b4ed ("tcp: Extend
> SOF_TIMESTAMPING_RX_SOFTWARE to TCP recvmsg") which also match this
> behavior.
>
> Co-developed-by: Iris Liu <iris@onechronos.com>
> Signed-off-by: Iris Liu <iris@onechronos.com>
> Signed-off-by: Kelly Littlepage <kelly@onechronos.com>
> ---
> Thanks and credit to Willem de Bruijn for the revised commit language

Thanks for resubmitting. I did not mean to put the Fixes tag in the
subject line.

The Fixes tag goes at the top of the block of signs-offs. If unclear,
please look at a couple of examples on the mailing list or in git log.

The existing subject from v1 was fine. It is now too long. Could you
resubmit a v3?

Thanks




>
>  net/ipv4/tcp.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 6d87de434377..e72bd651d21a 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -2154,13 +2154,15 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
>                         tp->urg_data = 0;
>                         tcp_fast_path_check(sk);
>                 }
> -               if (used + offset < skb->len)
> -                       continue;
>
>                 if (TCP_SKB_CB(skb)->has_rxtstamp) {
>                         tcp_update_recv_tstamps(skb, &tss);
>                         cmsg_flags |= 2;
>                 }
> +
> +               if (used + offset < skb->len)
> +                       continue;
> +
>                 if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
>                         goto found_fin_ok;
>                 if (!(flags & MSG_PEEK))
> --
> 2.26.2
>
>
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