From: Paolo Abeni pabeni@redhat.com
[ Upstream commit 617612316953093bc859890e405e1b550c27d840 ]
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 pabeni@redhat.com Reviewed-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: David S. Miller davem@davemloft.net Stable-dep-of: 5b825727d087 ("mptcp: add annotations around msk->subflow accesses") Signed-off-by: Sasha Levin sashal@kernel.org --- 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 b998e9df53cef..676a6d24b4b71 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -3157,7 +3157,7 @@ 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; @@ -3377,7 +3377,7 @@ 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; @@ -3723,7 +3723,10 @@ 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;