[PATCH mptcp-next RFC 1/3] mptcp: no longer fully_established after a fallback

When a fallback is done, the MPTCP_FALLBACK_DONE bit is set, which is
protected by the fallback lock. That's good, but while at it, the msk
fully established state can also be reset, to easily prevent some
operations.

This is just an optimisation to bail early in some situations: with the
PM, or when receiving an MP_JOIN. This is not a protection that requires
locks to avoid races: the fallback lock and other variables are there
for that.

Signed-off-by: Matthieu Baerts (NGI0) <[email protected]>
---
 net/mptcp/protocol.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index c2762d74f29d..a3982e4ed553 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -94,6 +94,7 @@ bool __mptcp_try_fallback(struct mptcp_sock *msk, int fb_mib)
 		return false;
 	}
 
+	WRITE_ONCE(msk->fully_established, false);
 	msk->allow_subflows = false;
 	set_bit(MPTCP_FALLBACK_DONE, &msk->flags);
 	__MPTCP_INC_STATS(net, fb_mib);

-- 
2.53.0