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inet: don't check for bind conflicts twice when searching for a port 

This is just wasted time, we've already found a tb that doesn't have a bind
conflict, and we don't drop the head lock so scanning again isn't going to give
us a different answer.  Instead move the tb->reuse setting logic outside of the
found_tb path and put it in the success: path.  Then make it so that we don't
goto again if we find a bind conflict in the found_tb path as we won't reach
this anymore when we are scanning for an ephemeral port.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Josef Bacik 2017-01-17 07:51:04 -08:00 committed by David S. Miller
parent b9470c2760
commit 6cd6661683
1 changed files with 11 additions and 20 deletions
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31
net/ipv4/inet_connection_sock.c
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@ -164,7 +164,7 @@ 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;
@ -183,7 +183,6 @@ 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);
@ -221,7 +220,7 @@ other_parity_scan:
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;
goto success;
goto next_port;
}
goto tb_not_found;
@ -256,23 +255,11 @@ 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 {
}
success:
if (!hlist_empty(&tb->owners)) {
tb->fastreuse = reuse;
if (sk->sk_reuseport) {
tb->fastreuseport = 1;
@ -280,8 +267,12 @@ tb_found:
} else {
tb->fastreuseport = 0;
}
} else {
if (!reuse)
tb->fastreuse = 0;
if (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid))
tb->fastreuseport = 0;
}
success:
if (!inet_csk(sk)->icsk_bind_hash)
inet_bind_hash(sk, tb, port);
WARN_ON(inet_csk(sk)->icsk_bind_hash != tb);