From 617612316953093bc859890e405e1b550c27d840 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 14 Apr 2023 16:08:01 +0200 Subject: [PATCH] mptcp: avoid unneeded __mptcp_nmpc_socket() usage In a few spots, the mptcp code invokes the __mptcp_nmpc_socket() helper multiple times under the same socket lock scope. Additionally, in such places, the socket status ensures that there is no MP capable handshake running. Under the above condition we can replace the later __mptcp_nmpc_socket() helper invocation with direct access to the msk->subflow pointer and better document such access is not supposed to fail with WARN(). Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts Signed-off-by: Matthieu Baerts Signed-off-by: David S. Miller --- net/mptcp/protocol.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index e6cb36784a68..9cdcfdb44aee 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -3143,7 +3143,7 @@ static struct sock *mptcp_accept(struct sock *sk, int flags, int *err, struct socket *listener; struct sock *newsk; - listener = __mptcp_nmpc_socket(msk); + listener = msk->subflow; if (WARN_ON_ONCE(!listener)) { *err = -EINVAL; return NULL; @@ -3363,7 +3363,7 @@ static int mptcp_get_port(struct sock *sk, unsigned short snum) struct mptcp_sock *msk = mptcp_sk(sk); struct socket *ssock; - ssock = __mptcp_nmpc_socket(msk); + ssock = msk->subflow; pr_debug("msk=%p, subflow=%p", msk, ssock); if (WARN_ON_ONCE(!ssock)) return -EINVAL; @@ -3709,7 +3709,10 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, pr_debug("msk=%p", msk); - ssock = __mptcp_nmpc_socket(msk); + /* buggy applications can call accept on socket states other then LISTEN + * but no need to allocate the first subflow just to error out. + */ + ssock = msk->subflow; if (!ssock) return -EINVAL;