rxrpc: Fix received abort handling

AF_RXRPC is incorrectly sending back to the server any abort it receives
for a client connection. This is due to the final-ACK offload to the
connection event processor patch. The abort code is copied into the
last-call information on the connection channel and then the event
processor is set.

Instead, the following should be done:

(1) In the case of a final-ACK for a successful call, the ACK should be
scheduled as before.

(2) In the case of a locally generated ABORT, the ABORT details should be
cached for sending in response to further packets related to that
call and no further action scheduled at call disconnect time.

(3) In the case of an ACK received from the peer, the call should be
considered dead, no ABORT should be transmitted at this time. In
response to further non-ABORT packets from the peer relating to this
call, an RX_USER_ABORT ABORT should be transmitted.

(4) In the case of a call killed due to network error, an RX_USER_ABORT
ABORT should be cached for transmission in response to further
packets, but no ABORT should be sent at this time.

Fixes: 3136ef49a14c ("rxrpc: Delay terminal ACK transmission on a client call")
Signed-off-by: David Howells <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/rxrpc/conn_client.c

···
 	 * can be skipped if we find a follow-on call.  The first DATA packet
 	 * of the follow on call will implicitly ACK this call.
 	 */
-	if (test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
+	if (call->completion == RXRPC_CALL_SUCCEEDED &&
+	    test_bit(RXRPC_CALL_EXPOSED, &call->flags)) {
 		unsigned long final_ack_at = jiffies + 2;
 
 		WRITE_ONCE(chan->final_ack_at, final_ack_at);

net/rxrpc/conn_object.c

···
 		 * through the channel, whilst disposing of the actual call record.
 		 */
 		trace_rxrpc_disconnect_call(call);
-		if (call->abort_code) {
-			chan->last_abort = call->abort_code;
-			chan->last_type = RXRPC_PACKET_TYPE_ABORT;
-		} else {
+		switch (call->completion) {
+		case RXRPC_CALL_SUCCEEDED:
 			chan->last_seq = call->rx_hard_ack;
 			chan->last_type = RXRPC_PACKET_TYPE_ACK;
+			break;
+		case RXRPC_CALL_LOCALLY_ABORTED:
+			chan->last_abort = call->abort_code;
+			chan->last_type = RXRPC_PACKET_TYPE_ABORT;
+			break;
+		default:
+			chan->last_abort = RX_USER_ABORT;
+			chan->last_type = RXRPC_PACKET_TYPE_ABORT;
+			break;
 		}
+
 		/* Sync with rxrpc_conn_retransmit(). */
 		smp_wmb();
 		chan->last_call = chan->call_id;