net/smc: improve state change handling after close wait

When a socket is closed or shutdown, smc waits for data being transmitted
in certain states. If the state changes during this wait, the close
switch depending on state should be reentered.
In addition, state change is avoided if sending of close or shutdown fails.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/smc_close.c

@@ -165,9 +165,9 @@ int smc_close_active(struct smc_sock *smc)
 		  0 : sock_flag(sk, SOCK_LINGER) ?
 		      sk->sk_lingertime : SMC_MAX_STREAM_WAIT_TIMEOUT;
 
-again:
 	old_state = sk->sk_state;
-	switch (old_state) {
+again:
+	switch (sk->sk_state) {
 	case SMC_INIT:
 		sk->sk_state = SMC_CLOSED;
 		if (smc->smc_listen_work.func)
@@ -194,6 +194,8 @@ again:
 		if (sk->sk_state == SMC_ACTIVE) {
 			/* send close request */
 			rc = smc_close_final(conn);
+			if (rc)
+				break;
 			sk->sk_state = SMC_PEERCLOSEWAIT1;
 		} else {
 			/* peer event has changed the state */
@@ -206,6 +208,8 @@ again:
 		    !smc_close_sent_any_close(conn)) {
 			/* just shutdown wr done, send close request */
 			rc = smc_close_final(conn);
+			if (rc)
+				break;
 		}
 		sk->sk_state = SMC_CLOSED;
 		break;
@@ -216,12 +220,13 @@ again:
 		release_sock(sk);
 		cancel_delayed_work_sync(&conn->tx_work);
 		lock_sock(sk);
-		if (sk->sk_err != ECONNABORTED) {
-			/* confirm close from peer */
-			rc = smc_close_final(conn);
-			if (rc)
-				break;
-		}
+		if (sk->sk_state != SMC_APPCLOSEWAIT1 &&
+		    sk->sk_state != SMC_APPCLOSEWAIT2)
+			goto again;
+		/* confirm close from peer */
+		rc = smc_close_final(conn);
+		if (rc)
+			break;
 		if (smc_cdc_rxed_any_close(conn))
 			/* peer has closed the socket already */
 			sk->sk_state = SMC_CLOSED;
@@ -235,6 +240,8 @@ again:
 		    !smc_close_sent_any_close(conn)) {
 			/* just shutdown wr done, send close request */
 			rc = smc_close_final(conn);
+			if (rc)
+				break;
 		}
 		/* peer sending PeerConnectionClosed will cause transition */
 		break;
@@ -401,20 +408,21 @@ int smc_close_shutdown_write(struct smc_sock *smc)
 		  0 : sock_flag(sk, SOCK_LINGER) ?
 		      sk->sk_lingertime : SMC_MAX_STREAM_WAIT_TIMEOUT;
 
-again:
 	old_state = sk->sk_state;
-	switch (old_state) {
+again:
+	switch (sk->sk_state) {
 	case SMC_ACTIVE:
 		smc_close_stream_wait(smc, timeout);
 		release_sock(sk);
 		cancel_delayed_work_sync(&conn->tx_work);
 		lock_sock(sk);
+		if (sk->sk_state != SMC_ACTIVE)
+			goto again;
 		/* send close wr request */
 		rc = smc_close_wr(conn);
-		if (sk->sk_state == SMC_ACTIVE)
-			sk->sk_state = SMC_PEERCLOSEWAIT1;
-		else
-			goto again;
+		if (rc)
+			break;
+		sk->sk_state = SMC_PEERCLOSEWAIT1;
 		break;
 	case SMC_APPCLOSEWAIT1:
 		/* passive close */
@@ -423,8 +431,12 @@ again:
 		release_sock(sk);
 		cancel_delayed_work_sync(&conn->tx_work);
 		lock_sock(sk);
+		if (sk->sk_state != SMC_APPCLOSEWAIT1)
+			goto again;
 		/* confirm close from peer */
 		rc = smc_close_wr(conn);
+		if (rc)
+			break;
 		sk->sk_state = SMC_APPCLOSEWAIT2;
 		break;
 	case SMC_APPCLOSEWAIT2: