From: Hannes Frederic Sowa <hannes@stressinduktion.org>
To: Josef Bacik <jbacik@fb.com>,
davem@davemloft.net, kraigatgoog@gmail.com,
eric.dumazet@gmail.com, tom@herbertland.com,
netdev@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH 3/5 net-next] inet: don't check for bind conflicts twice when searching for a port
Date: Wed, 21 Dec 2016 16:08:32 +0100 [thread overview]
Message-ID: <1482332912.2260.8.camel@stressinduktion.org> (raw)
In-Reply-To: <1482264424-15439-4-git-send-email-jbacik@fb.com>
On Tue, 2016-12-20 at 15:07 -0500, Josef Bacik wrote:
> --- a/net/ipv4/inet_connection_sock.c
> +++ b/net/ipv4/inet_connection_sock.c
> @@ -92,7 +92,7 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum)
> {
> bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
> struct inet_hashinfo *hinfo = sk->sk_prot->h.hashinfo;
> - int ret = 1, attempts = 5, port = snum;
> + int ret = 1, port = snum;
> struct inet_bind_hashbucket *head;
> struct net *net = sock_net(sk);
> int i, low, high, attempt_half;
> @@ -100,6 +100,7 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum)
> kuid_t uid = sock_i_uid(sk);
> u32 remaining, offset;
> bool reuseport_ok = !!snum;
> + bool empty_tb = true;
>
> if (port) {
> head = &hinfo->bhash[inet_bhashfn(net, port,
> @@ -111,7 +112,6 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum)
>
> goto tb_not_found;
> }
> -again:
> attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
> other_half_scan:
> inet_get_local_port_range(net, &low, &high);
> @@ -148,8 +148,12 @@ other_parity_scan:
> spin_lock_bh(&head->lock);
> inet_bind_bucket_for_each(tb, &head->chain)
> if (net_eq(ib_net(tb), net) && tb->port == port) {
> - if (!inet_csk_bind_conflict(sk, tb, false, reuseport_ok))
> - goto tb_found;
> + if (hlist_empty(&tb->owners))
> + goto success;
> + if (!inet_csk_bind_conflict(sk, tb, false, reuseport_ok)) {
> + empty_tb = false;
> + goto success;
> + }
> goto next_port;
> }
> goto tb_not_found;
> @@ -184,23 +188,12 @@ tb_found:
> !rcu_access_pointer(sk->sk_reuseport_cb) &&
> sk->sk_reuseport && uid_eq(tb->fastuid, uid)))
> goto success;
> - if (inet_csk_bind_conflict(sk, tb, true, reuseport_ok)) {
> - if ((reuse ||
> - (tb->fastreuseport > 0 &&
> - sk->sk_reuseport &&
> - !rcu_access_pointer(sk->sk_reuseport_cb) &&
> - uid_eq(tb->fastuid, uid))) && !snum &&
> - --attempts >= 0) {
> - spin_unlock_bh(&head->lock);
> - goto again;
> - }
> + if (inet_csk_bind_conflict(sk, tb, true, reuseport_ok))
> goto fail_unlock;
> - }
> - if (!reuse)
> - tb->fastreuse = 0;
> - if (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid))
> - tb->fastreuseport = 0;
> - } else {
> + empty_tb = false;
> + }
> +success:
> + if (empty_tb) {
I would fine it even more simple to read, if you redo the hlist_empty
check here instead of someone has to review all the paths where this
might get set. hlist_empty is a very quick test.
Thanks,
Hannes
next prev parent reply other threads:[~2016-12-21 15:08 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-20 20:06 [RFC][PATCH 0/5 net-next] Rework inet_csk_get_port Josef Bacik
2016-12-20 20:07 ` [PATCH 1/5 net-next] inet: replace ->bind_conflict with ->rcv_saddr_equal Josef Bacik
2016-12-21 15:06 ` Hannes Frederic Sowa
2016-12-21 15:16 ` Josef Bacik
2016-12-22 20:00 ` Hannes Frederic Sowa
2016-12-21 15:23 ` Hannes Frederic Sowa
2016-12-21 15:59 ` Josef Bacik
2016-12-21 18:28 ` David Miller
2016-12-20 20:07 ` [PATCH 2/5 net-next] inet: kill smallest_size and smallest_port Josef Bacik
2016-12-21 18:30 ` David Miller
2016-12-21 19:29 ` Eric Dumazet
2016-12-21 19:32 ` Josef Bacik
2016-12-20 20:07 ` [PATCH 3/5 net-next] inet: don't check for bind conflicts twice when searching for a port Josef Bacik
2016-12-21 15:08 ` Hannes Frederic Sowa [this message]
2016-12-21 15:12 ` Josef Bacik
2016-12-20 20:07 ` [PATCH 4/5 net-next] inet: split inet_csk_get_port into two functions Josef Bacik
2016-12-20 20:07 ` [PATCH 5/5 net-next] inet: reset tb->fastreuseport when adding a reuseport sk Josef Bacik
2016-12-21 16:49 ` Craig Gallek
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