[SCSI] iscsi_tcp: Evaluate socket state in data_ready()

The network core will call the state_change() callback
prior to the data_ready() callback, which might cause
us to lose a connection state change.
So we have to evaluate the socket state at the end
of the data_ready() callback, too.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/iscsi_tcp.c

@@ -99,6 +99,24 @@ static int iscsi_sw_tcp_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
 	return total_consumed;
 }
 
+/**
+ * iscsi_sw_sk_state_check - check socket state
+ * @sk: socket
+ *
+ * If the socket is in CLOSE or CLOSE_WAIT we should
+ * not close the connection if there is still some
+ * data pending.
+ */
+static inline int iscsi_sw_sk_state_check(struct sock *sk)
+{
+	if ((sk->sk_state == TCP_CLOSE_WAIT ||
+	     sk->sk_state == TCP_CLOSE) &&
+	    !atomic_read(&sk->sk_rmem_alloc))
+		return -ECONNRESET;
+
+	return 0;
+}
+
 static void iscsi_sw_tcp_data_ready(struct sock *sk, int flag)
 {
 	struct iscsi_conn *conn = sk->sk_user_data;
@@ -117,6 +135,12 @@ static void iscsi_sw_tcp_data_ready(struct sock *sk, int flag)
 	rd_desc.count = 1;
 	tcp_read_sock(sk, &rd_desc, iscsi_sw_tcp_recv);
 
+	if (iscsi_sw_sk_state_check(sk) < 0) {
+		ISCSI_SW_TCP_DBG(conn, "iscsi_tcp_data_ready: "
+				 "TCP_CLOSE|TCP_CLOSE_WAIT\n");
+		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+	}
+
 	read_unlock(&sk->sk_callback_lock);
 
 	/* If we had to (atomically) map a highmem page,
@@ -137,9 +161,7 @@ static void iscsi_sw_tcp_state_change(struct sock *sk)
 	conn = (struct iscsi_conn*)sk->sk_user_data;
 	session = conn->session;
 
-	if ((sk->sk_state == TCP_CLOSE_WAIT ||
-	     sk->sk_state == TCP_CLOSE) &&
-	    !atomic_read(&sk->sk_rmem_alloc)) {
+	if (iscsi_sw_sk_state_check(sk) < 0) {
 		ISCSI_SW_TCP_DBG(conn, "iscsi_tcp_state_change: "
 				 "TCP_CLOSE|TCP_CLOSE_WAIT\n");
 		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);