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From:   Xin Long <lucien.xin@gmail.com>
Date:   Mon, 5 Jul 2021 21:12:54 -0400
Message-ID: <CADvbK_dXKK4-t02hUDMPf_O=L8WD7_=aH7c9VmL0ZgtVE_4nUg@mail.gmail.com>
Subject: Re: [PATCH] net: Fix called net_enable_timestamp() in sctp_copy_sock()
To:     Yajun Deng <yajun.deng@linux.dev>
Cc:     davem <davem@davemloft.net>, Jakub Kicinski <kuba@kernel.org>,
        Vlad Yasevich <vyasevich@gmail.com>,
        Neil Horman <nhorman@tuxdriver.com>,
        Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
        Paolo Abeni <pabeni@redhat.com>,
        mathew.j.martineau@linux.intel.com,
        Eric Dumazet <edumazet@google.com>, aahringo@redhat.com,
        linmiaohe@huawei.com, Florian Westphal <fw@strlen.de>,
        xiangxia.m.yue@gmail.com, Kees Cook <keescook@chromium.org>,
        LKML <linux-kernel@vger.kernel.org>,
        "linux-sctp @ vger . kernel . org" <linux-sctp@vger.kernel.org>
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On Mon, Jul 5, 2021 at 8:34 AM Yajun Deng <yajun.deng@linux.dev> wrote:
>
> Add sock_needs_netstamp() judgment condition when need to call
> net_enable_timestamp().
Why do we need this when it always returns true for SCTP?

>
> Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
> ---
>  include/net/sock.h | 1 +
>  net/core/sock.c    | 2 +-
>  net/sctp/socket.c  | 2 +-
>  3 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/include/net/sock.h b/include/net/sock.h
> index 8bdd80027ffb..e36563576758 100644
> --- a/include/net/sock.h
> +++ b/include/net/sock.h
> @@ -2757,6 +2757,7 @@ int sock_bindtoindex(struct sock *sk, int ifindex, bool lock_sk);
>  void sock_set_timestamp(struct sock *sk, int optname, bool valbool);
>  int sock_set_timestamping(struct sock *sk, int optname, int val);
>
> +bool sock_needs_netstamp(const struct sock *sk);
>  void sock_enable_timestamps(struct sock *sk);
>  void sock_no_linger(struct sock *sk);
>  void sock_set_keepalive(struct sock *sk);
> diff --git a/net/core/sock.c b/net/core/sock.c
> index ba1c0f75cd45..ce6ec9f8ac7c 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -429,7 +429,7 @@ static int sock_set_timeout(long *timeo_p, sockptr_t optval, int optlen,
>         return 0;
>  }
>
> -static bool sock_needs_netstamp(const struct sock *sk)
> +bool sock_needs_netstamp(const struct sock *sk)
>  {
>         switch (sk->sk_family) {
>         case AF_UNSPEC:
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index e64e01f61b11..30d90735beb0 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -9449,7 +9449,7 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
>         newinet->mc_index = 0;
>         newinet->mc_list = NULL;
>
> -       if (newsk->sk_flags & SK_FLAGS_TIMESTAMP)
> +       if (sock_needs_netstamp(newsk) && newsk->sk_flags & SK_FLAGS_TIMESTAMP)
>                 net_enable_timestamp();
>
>         /* Set newsk security attributes from original sk and connection
> --
> 2.32.0
>