From: Josef Bacik <jbacik@fb.com>
To: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: <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 10:12:41 -0500 [thread overview]
Message-ID: <1482333161.24490.11@smtp.office365.com> (raw)
In-Reply-To: <1482332912.2260.8.camel@stressinduktion.org>
On Wed, Dec 21, 2016 at 10:08 AM, Hannes Frederic Sowa
<hannes@stressinduktion.org> wrote:
> 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.
Yup that's fair, I'll fix that up. Thanks,
Josef
next prev parent reply other threads:[~2016-12-21 15:13 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
2016-12-21 15:12 ` Josef Bacik [this message]
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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