diff options
| author | Kuniyuki Iwashima <kuniyu@amazon.com> | 2024-06-04 09:52:38 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-07-05 09:00:21 +0200 |
| commit | b56ff0d20a4a60b9e6424d0609acccbbde573ea8 (patch) | |
| tree | 1e10c19dd65f9cb6c1a1587b24e3f153574aa64b | |
| parent | f5cf5e139ec736f1ac18cda8d5e5fc80d7eef787 (diff) | |
af_unix: Use unix_recvq_full_lockless() in unix_stream_connect().
[ Upstream commit 45d872f0e65593176d880ec148f41ad7c02e40a7 ]
Once sk->sk_state is changed to TCP_LISTEN, it never changes.
unix_accept() takes advantage of this characteristics; it does not
hold the listener's unix_state_lock() and only acquires recvq lock
to pop one skb.
It means unix_state_lock() does not prevent the queue length from
changing in unix_stream_connect().
Thus, we need to use unix_recvq_full_lockless() to avoid data-race.
Now we remove unix_recvq_full() as no one uses it.
Note that we can remove READ_ONCE() for sk->sk_max_ack_backlog in
unix_recvq_full_lockless() because of the following reasons:
(1) For SOCK_DGRAM, it is a written-once field in unix_create1()
(2) For SOCK_STREAM and SOCK_SEQPACKET, it is changed under the
listener's unix_state_lock() in unix_listen(), and we hold
the lock in unix_stream_connect()
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/unix/af_unix.c | 10 |
1 files changed, 2 insertions, 8 deletions
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 4a4b6d254453..dfcafbb8cd0e 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -194,15 +194,9 @@ static inline int unix_may_send(struct sock *sk, struct sock *osk) return unix_peer(osk) == NULL || unix_our_peer(sk, osk); } -static inline int unix_recvq_full(const struct sock *sk) -{ - return skb_queue_len(&sk->sk_receive_queue) > sk->sk_max_ack_backlog; -} - static inline int unix_recvq_full_lockless(const struct sock *sk) { - return skb_queue_len_lockless(&sk->sk_receive_queue) > - READ_ONCE(sk->sk_max_ack_backlog); + return skb_queue_len_lockless(&sk->sk_receive_queue) > sk->sk_max_ack_backlog; } struct sock *unix_peer_get(struct sock *s) @@ -1306,7 +1300,7 @@ restart: if (other->sk_shutdown & RCV_SHUTDOWN) goto out_unlock; - if (unix_recvq_full(other)) { + if (unix_recvq_full_lockless(other)) { err = -EAGAIN; if (!timeo) goto out_unlock; |