Revert "rxrpc: Allow failed client calls to be retried"

The changes introduced to allow rxrpc calls to be retried creates an issue
when it comes to refcounting afs_call structs.  The problem is that when
rxrpc_send_data() queues the last packet for an asynchronous call, the
following sequence can occur:

 (1) The notify_end_tx callback is invoked which causes the state in the
     afs_call to be changed from AFS_CALL_CL_REQUESTING or
     AFS_CALL_SV_REPLYING.

 (2) afs_deliver_to_call() can then process event notifications from rxrpc
     on the async_work queue.

 (3) Delivery of events, such as an abort from the server, can cause the
     afs_call state to be changed to AFS_CALL_COMPLETE on async_work.

 (4) For an asynchronous call, afs_process_async_call() notes that the call
     is complete and tried to clean up all the refs on async_work.

 (5) rxrpc_send_data() might return the amount of data transferred
     (success) or an error - which could in turn reflect a local error or a
     received error.

Synchronising the clean up after rxrpc_kernel_send_data() returns an error
with the asynchronous cleanup is then tricky to get right.

Mostly revert commit c038a58ccfd6704d4d7d60ed3d6a0fca13cf13a4.  The two API
functions the original commit added aren't currently used.  This makes
rxrpc_kernel_send_data() always return successfully if it queued the data
it was given.

Note that this doesn't affect synchronous calls since their Rx notification
function merely pokes a wait queue and does not refcounting.  The
asynchronous call notification function *has* to do refcounting and pass a
ref over the work item to avoid the need to sync the workqueue in call
cleanup.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 13 deletions

diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index be01f9c5d963..46c9312085b1 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -169,10 +169,8 @@ static void rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
 
 	ASSERTCMP(seq, ==, call->tx_top + 1);
 
-	if (last) {
+	if (last)
 		annotation |= RXRPC_TX_ANNO_LAST;
-		set_bit(RXRPC_CALL_TX_LASTQ, &call->flags);
-	}
 
 	/* We have to set the timestamp before queueing as the retransmit
 	 * algorithm can see the packet as soon as we queue it.
@@ -386,6 +384,11 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 				call->tx_total_len -= copy;
 		}
 
+		/* check for the far side aborting the call or a network error
+		 * occurring */
+		if (call->state == RXRPC_CALL_COMPLETE)
+			goto call_terminated;
+
 		/* add the packet to the send queue if it's now full */
 		if (sp->remain <= 0 ||
 		    (msg_data_left(msg) == 0 && !more)) {
@@ -425,16 +428,6 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
 					   notify_end_tx);
 			skb = NULL;
 		}
-
-		/* Check for the far side aborting the call or a network error
-		 * occurring.  If this happens, save any packet that was under
-		 * construction so that in the case of a network error, the
-		 * call can be retried or redirected.
-		 */
-		if (call->state == RXRPC_CALL_COMPLETE) {
-			ret = call->error;
-			goto out;
-		}
 	} while (msg_data_left(msg) > 0);
 
 success:
@@ -444,6 +437,11 @@ out:
 	_leave(" = %d", ret);
 	return ret;
 
+call_terminated:
+	rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
+	_leave(" = %d", call->error);
+	return call->error;
+
 maybe_error:
 	if (copied)
 		goto success;