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From:   Tim Froidcoeur <tim.froidcoeur@tessares.net>
To:     linux-kernel@vger.kernel.org
Cc:     stable@vger.kernel.org, gregkh@linuxfoundation.org,
        matthieu.baerts@tessares.net, davem@davemloft.net,
        Tim Froidcoeur <tim.froidcoeur@tessares.net>
Subject: [PATCH 4.9 1/2] net: refactor bind_bucket fastreuse into helper
Date:   Wed,  2 Sep 2020 16:05:44 +0200
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[ Upstream commit 62ffc589abb176821662efc4525ee4ac0b9c3894 ]

Refactor the fastreuse update code in inet_csk_get_port into a small
helper function that can be called from other places.

Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Tim Froidcoeur <tim.froidcoeur@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Tim Froidcoeur <tim.froidcoeur@tessares.net>
---
 include/net/inet_connection_sock.h |  4 ++++
 net/ipv4/inet_connection_sock.c    | 37 ++++++++++++++++++++----------
 2 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index 146054ceea8e..5bb56ebf3c9f 100644
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -319,5 +319,9 @@ int inet_csk_compat_getsockopt(struct sock *sk, int level, int optname,
 int inet_csk_compat_setsockopt(struct sock *sk, int level, int optname,
 			       char __user *optval, unsigned int optlen);
 
+/* update the fast reuse flag when adding a socket */
+void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
+			       struct sock *sk);
+
 struct dst_entry *inet_csk_update_pmtu(struct sock *sk, u32 mtu);
 #endif /* _INET_CONNECTION_SOCK_H */
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 1bcbb7399fe6..5a0352ccadd3 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -89,6 +89,28 @@ int inet_csk_bind_conflict(const struct sock *sk,
 }
 EXPORT_SYMBOL_GPL(inet_csk_bind_conflict);
 
+void inet_csk_update_fastreuse(struct inet_bind_bucket *tb,
+			       struct sock *sk)
+{
+	kuid_t uid = sock_i_uid(sk);
+	bool reuse = sk->sk_reuse && sk->sk_state != TCP_LISTEN;
+
+	if (!hlist_empty(&tb->owners)) {
+		if (!reuse)
+			tb->fastreuse = 0;
+		if (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid))
+			tb->fastreuseport = 0;
+	} else {
+		tb->fastreuse = reuse;
+		if (sk->sk_reuseport) {
+			tb->fastreuseport = 1;
+			tb->fastuid = uid;
+		} else {
+			tb->fastreuseport = 0;
+		}
+	}
+}
+
 /* Obtain a reference to a local port for the given sock,
  * if snum is zero it means select any available local port.
  * We try to allocate an odd port (and leave even ports for connect())
@@ -218,19 +240,10 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum)
 			}
 			goto fail_unlock;
 		}
-		if (!reuse)
-			tb->fastreuse = 0;
-		if (!sk->sk_reuseport || !uid_eq(tb->fastuid, uid))
-			tb->fastreuseport = 0;
-	} else {
-		tb->fastreuse = reuse;
-		if (sk->sk_reuseport) {
-			tb->fastreuseport = 1;
-			tb->fastuid = uid;
-		} else {
-			tb->fastreuseport = 0;
-		}
 	}
+
+	inet_csk_update_fastreuse(tb, sk);
+
 success:
 	if (!inet_csk(sk)->icsk_bind_hash)
 		inet_bind_hash(sk, tb, port);
-- 
2.25.1