[PATCH mptcp-next RFC v5 2/3] mptcp: fallback immediately on MP_FAIL reception

[Chenguang Zhao <chenguang.zhao@linux.dev>]

From: Chenguang Zhao <zhaochenguang@kylinos.cn>

Call mptcp_try_fallback() right after the MP_FAIL response
ACK, and simplify mptcp_update_infinite_map() accordingly.

Fixes: 1e39e5a32ad7 ("mptcp: infinite mapping sending")
Signed-off-by: Chenguang Zhao <zhaochenguang@kylinos.cn>
---
 net/mptcp/pm.c       | 5 +++++
 net/mptcp/protocol.c | 8 +-------
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index ba7c6f80a183..69701ac7e436 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -895,6 +895,11 @@ void mptcp_pm_mp_fail_received(struct sock *sk, u64 fail_seq)
 		pr_debug("MP_FAIL response received\n");
 		WRITE_ONCE(subflow->fail_tout, 0);
 	}
+
+	if (!mptcp_try_fallback(sk, MPTCP_MIB_MPFAILFALLBACK)) {
+		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_FALLBACKFAILED);
+		mptcp_subflow_reset(sk);
+	}
 }
 
 static int mptcp_add_addr_len(int family, bool echo, bool port)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index f879b1061f2d..abe45a31ca5f 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1417,13 +1417,7 @@ static void mptcp_update_infinite_map(struct mptcp_sock *msk,
 
 	mpext->infinite_map = 1;
 	mpext->data_len = 0;
-
-	if (!mptcp_try_fallback(ssk, MPTCP_MIB_INFINITEMAPTX)) {
-		MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_FALLBACKFAILED);
-		mptcp_subflow_reset(ssk);
-		return;
-	}
-
+	MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX);
 	mptcp_subflow_ctx(ssk)->send_infinite_map = 0;
 }
 
-- 
2.25.1