Messages in this thread | | | From | Yafang Shao <> | Date | Mon, 8 Oct 2018 18:46:58 +0800 | Subject | Re: [PATCH v2 net-next] inet: do not set backlog if listen fails |
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On Mon, Oct 8, 2018 at 1:39 AM Eric Dumazet <eric.dumazet@gmail.com> wrote: > > > > On 10/07/2018 06:36 AM, Yafang Shao wrote: > > We don't need to set the backlog if listen fails. > > The sk_max_ack_backlog will be set in the caller inet_listen() and > > dccp_listen_start() if inet_csk_listen_start() return without error. > > So just remove this line to avoid this unnecessary operation. > > > > Regarding sk_ack_backlog, we have to set it before a TCP/DCCP socket is > > ready to accept new flows to avoid race, because dccp and tcp have lockless > > listeners > > > > Really could you not add irrelevant stuff in the changelog ? >
Sure, I will remove it.
> This patch simply removes one redundant setting, you do not have to explain > about dccp/tcp being lockless and that sk_ack_backlog is not touched by this patch. > > Also the title is misleading, since we will still set the backlog even if the listen > fails. > > If you really want sk_max_ack_backlog being not changed if listen() fails, > then I am afraid you will need to submit a different patch.
After this patch, sk_max_ack_backlog will only be set after the sk is successfully added to listening hash table, and then 0 is returned, that means listen() is successful.
Take inet_listen() for example,
if (old_state != TCP_LISTEN) { err = inet_csk_listen_start(sk, backlog); if (err) goto out; }
// it can only be set if err is 0. sk->sk_max_ack_backlog = backlog; err = 0;
out: return err;
Pls. correct me if I missed something.
Thanks Yafang
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