af_iucv: sync sk shutdown flag if iucv path is quiesced

If the af_iucv communication partner quiesces the path to shutdown its
receive direction, provide a quiesce callback implementation to shutdown
the (local) send direction. This ensures that both sides are synchronized.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/iucv/af_iucv.c

@@ -54,6 +54,7 @@ static void iucv_callback_connack(struct iucv_path *, u8 ipuser[16]);
 static int iucv_callback_connreq(struct iucv_path *, u8 ipvmid[8],
 				 u8 ipuser[16]);
 static void iucv_callback_connrej(struct iucv_path *, u8 ipuser[16]);
+static void iucv_callback_shutdown(struct iucv_path *, u8 ipuser[16]);
 
 static struct iucv_sock_list iucv_sk_list = {
 	.lock = __RW_LOCK_UNLOCKED(iucv_sk_list.lock),
@@ -65,7 +66,8 @@ static struct iucv_handler af_iucv_handler = {
 	.path_complete	  = iucv_callback_connack,
 	.path_severed	  = iucv_callback_connrej,
 	.message_pending  = iucv_callback_rx,
-	.message_complete = iucv_callback_txdone
+	.message_complete = iucv_callback_txdone,
+	.path_quiesced	  = iucv_callback_shutdown,
 };
 
 static inline void high_nmcpy(unsigned char *dst, char *src)
@@ -1196,6 +1198,21 @@ static void iucv_callback_connrej(struct iucv_path *path, u8 ipuser[16])
 	sk->sk_state_change(sk);
 }
 
+/* called if the other communication side shuts down its RECV direction;
+ * in turn, the callback sets SEND_SHUTDOWN to disable sending of data.
+ */
+static void iucv_callback_shutdown(struct iucv_path *path, u8 ipuser[16])
+{
+	struct sock *sk = path->private;
+
+	bh_lock_sock(sk);
+	if (sk->sk_state != IUCV_CLOSED) {
+		sk->sk_shutdown |= SEND_SHUTDOWN;
+		sk->sk_state_change(sk);
+	}
+	bh_unlock_sock(sk);
+}
+
 static struct proto_ops iucv_sock_ops = {
 	.family		= PF_IUCV,
 	.owner		= THIS_MODULE,