rxrpc: Add notification of end-of-Tx phase

Add a callback to rxrpc_kernel_send_data() so that a kernel service can get
a notification that the AF_RXRPC call has transitioned out the Tx phase and
is now waiting for a reply or a final ACK.

This is called from AF_RXRPC with the call state lock held so the
notification is guaranteed to come before any reply is passed back.

Further, modify the AFS filesystem to make use of this so that we don't have
to change the afs_call state before sending the last bit of data.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 27 insertions, 7 deletions

diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index bc7f0241d92b..344fdce89823 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -101,11 +101,23 @@ static inline void rxrpc_instant_resend(struct rxrpc_call *call, int ix)
 }
 
 /*
+ * Notify the owner of the call that the transmit phase is ended and the last
+ * packet has been queued.
+ */
+static void rxrpc_notify_end_tx(struct rxrpc_sock *rx, struct rxrpc_call *call,
+				rxrpc_notify_end_tx_t notify_end_tx)
+{
+	if (notify_end_tx)
+		notify_end_tx(&rx->sk, call, call->user_call_ID);
+}
+
+/*
  * Queue a DATA packet for transmission, set the resend timeout and send the
  * packet immediately
  */
-static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
-			       bool last)
+static void rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
+			       struct sk_buff *skb, bool last,
+			       rxrpc_notify_end_tx_t notify_end_tx)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 	rxrpc_seq_t seq = sp->hdr.seq;
@@ -141,6 +153,7 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
 		switch (call->state) {
 		case RXRPC_CALL_CLIENT_SEND_REQUEST:
 			call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
+			rxrpc_notify_end_tx(rx, call, notify_end_tx);
 			break;
 		case RXRPC_CALL_SERVER_ACK_REQUEST:
 			call->state = RXRPC_CALL_SERVER_SEND_REPLY;
@@ -153,6 +166,7 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
 				break;
 		case RXRPC_CALL_SERVER_SEND_REPLY:
 			call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
+			rxrpc_notify_end_tx(rx, call, notify_end_tx);
 			break;
 		default:
 			break;
@@ -189,7 +203,8 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
  */
 static int rxrpc_send_data(struct rxrpc_sock *rx,
 			   struct rxrpc_call *call,
-			   struct msghdr *msg, size_t len)
+			   struct msghdr *msg, size_t len,
+			   rxrpc_notify_end_tx_t notify_end_tx)
 {
 	struct rxrpc_skb_priv *sp;
 	struct sk_buff *skb;
@@ -350,7 +365,9 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 			if (ret < 0)
 				goto out;
 
-			rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
+			rxrpc_queue_packet(rx, call, skb,
+					   !msg_data_left(msg) && !more,
+					   notify_end_tx);
 			skb = NULL;
 		}
 	} while (msg_data_left(msg) > 0);
@@ -611,7 +628,7 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 		/* Reply phase not begun or not complete for service call. */
 		ret = -EPROTO;
 	} else {
-		ret = rxrpc_send_data(rx, call, msg, len);
+		ret = rxrpc_send_data(rx, call, msg, len, NULL);
 	}
 
 	mutex_unlock(&call->user_mutex);
@@ -631,6 +648,7 @@ error_release_sock:
  * @call: The call to send data through
  * @msg: The data to send
  * @len: The amount of data to send
+ * @notify_end_tx: Notification that the last packet is queued.
  *
  * Allow a kernel service to send data on a call.  The call must be in an state
  * appropriate to sending data.  No control data should be supplied in @msg,
@@ -638,7 +656,8 @@ error_release_sock:
  * more data to come, otherwise this data will end the transmission phase.
  */
 int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
-			   struct msghdr *msg, size_t len)
+			   struct msghdr *msg, size_t len,
+			   rxrpc_notify_end_tx_t notify_end_tx)
 {
 	int ret;
 
@@ -656,7 +675,8 @@ int rxrpc_kernel_send_data(struct socket *sock, struct rxrpc_call *call,
 	case RXRPC_CALL_CLIENT_SEND_REQUEST:
 	case RXRPC_CALL_SERVER_ACK_REQUEST:
 	case RXRPC_CALL_SERVER_SEND_REPLY:
-		ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len);
+		ret = rxrpc_send_data(rxrpc_sk(sock->sk), call, msg, len,
+				      notify_end_tx);
 		break;
 	case RXRPC_CALL_COMPLETE:
 		read_lock_bh(&call->state_lock);