mptcp: drop rm_addr_signal flag

This patch reused add_addr_signal for the RM_ADDR announcing signal, by
defining a new ADD_ADDR status named MPTCP_RM_ADDR_SIGNAL. Then the flag
rm_addr_signal in PM could be dropped.
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mptcp/pm.c

@@ -20,6 +20,11 @@ int mptcp_pm_announce_addr(struct mptcp_sock *msk,
 
 	pr_debug("msk=%p, local_id=%d", msk, addr->id);
 
+	if (add_addr) {
+		pr_warn("addr_signal error, add_addr=%d", add_addr);
+		return -EINVAL;
+	}
+
 	msk->pm.local = *addr;
 	add_addr |= BIT(MPTCP_ADD_ADDR_SIGNAL);
 	if (echo)
@@ -34,10 +39,18 @@ int mptcp_pm_announce_addr(struct mptcp_sock *msk,
 
 int mptcp_pm_remove_addr(struct mptcp_sock *msk, u8 local_id)
 {
+	u8 rm_addr = READ_ONCE(msk->pm.add_addr_signal);
+
 	pr_debug("msk=%p, local_id=%d", msk, local_id);
 
+	if (rm_addr) {
+		pr_warn("addr_signal error, rm_addr=%d", rm_addr);
+		return -EINVAL;
+	}
+
 	msk->pm.rm_id = local_id;
-	WRITE_ONCE(msk->pm.rm_addr_signal, true);
+	rm_addr |= BIT(MPTCP_RM_ADDR_SIGNAL);
+	WRITE_ONCE(msk->pm.add_addr_signal, rm_addr);
 	return 0;
 }
 
@@ -231,7 +244,7 @@ bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
 		goto out_unlock;
 
 	*rm_id = msk->pm.rm_id;
-	WRITE_ONCE(msk->pm.rm_addr_signal, false);
+	WRITE_ONCE(msk->pm.add_addr_signal, 0);
 	ret = true;
 
 out_unlock:
@@ -253,7 +266,6 @@ void mptcp_pm_data_init(struct mptcp_sock *msk)
 	msk->pm.rm_id = 0;
 	WRITE_ONCE(msk->pm.work_pending, false);
 	WRITE_ONCE(msk->pm.add_addr_signal, 0);
-	WRITE_ONCE(msk->pm.rm_addr_signal, false);
 	WRITE_ONCE(msk->pm.accept_addr, false);
 	WRITE_ONCE(msk->pm.accept_subflow, false);
 	msk->pm.status = 0;

net/mptcp/protocol.h

@@ -173,6 +173,7 @@ enum mptcp_add_addr_status {
 	MPTCP_ADD_ADDR_ECHO,
 	MPTCP_ADD_ADDR_IPV6,
 	MPTCP_ADD_ADDR_PORT,
+	MPTCP_RM_ADDR_SIGNAL,
 };
 
 struct mptcp_pm_data {
@@ -183,7 +184,6 @@ struct mptcp_pm_data {
 	spinlock_t	lock;		/*protects the whole PM data */
 
 	u8		add_addr_signal;
-	bool		rm_addr_signal;
 	bool		server_side;
 	bool		work_pending;
 	bool		accept_addr;
@@ -578,7 +578,7 @@ static inline bool mptcp_pm_should_add_signal_port(struct mptcp_sock *msk)
 
 static inline bool mptcp_pm_should_rm_signal(struct mptcp_sock *msk)
 {
-	return READ_ONCE(msk->pm.rm_addr_signal);
+	return READ_ONCE(msk->pm.add_addr_signal) & BIT(MPTCP_RM_ADDR_SIGNAL);
 }
 
 static inline unsigned int mptcp_add_addr_len(int family, bool echo, bool port)