rxrpc: Allow failed client calls to be retried

Allow a client call that failed on network error to be retried, provided
that the Tx queue still holds DATA packet 1.  This allows an operation to
be submitted to another server or another address for the same server
without having to repackage and re-encrypt the data so far processed.

Two new functions are provided:

 (1) rxrpc_kernel_check_call() - This is used to find out the completion
     state of a call to guess whether it can be retried and whether it
     should be retried.

 (2) rxrpc_kernel_retry_call() - Disconnect the call from its current
     connection, reset the state and submit it as a new client call to a
     new address.  The new address need not match the previous address.

A call may be retried even if all the data hasn't been loaded into it yet;
a partially constructed will be retained at the same point it was at when
an error condition was detected.  msg_data_left() can be used to find out
how much data was packaged before the error occurred.

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

1 files changed, 7 insertions, 12 deletions

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 227e247..ea5600b 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -445,6 +445,7 @@ enum rxrpc_call_flag {
 	RXRPC_CALL_EXPOSED,		/* The call was exposed to the world */
 	RXRPC_CALL_RX_LAST,		/* Received the last packet (at rxtx_top) */
 	RXRPC_CALL_TX_LAST,		/* Last packet in Tx buffer (at rxtx_top) */
+	RXRPC_CALL_TX_LASTQ,		/* Last packet has been queued */
 	RXRPC_CALL_SEND_PING,		/* A ping will need to be sent */
 	RXRPC_CALL_PINGING,		/* Ping in process */
 	RXRPC_CALL_RETRANS_TIMEOUT,	/* Retransmission due to timeout occurred */
@@ -482,18 +483,6 @@ enum rxrpc_call_state {
 };
 
 /*
- * Call completion condition (state == RXRPC_CALL_COMPLETE).
- */
-enum rxrpc_call_completion {
-	RXRPC_CALL_SUCCEEDED,		/* - Normal termination */
-	RXRPC_CALL_REMOTELY_ABORTED,	/* - call aborted by peer */
-	RXRPC_CALL_LOCALLY_ABORTED,	/* - call aborted locally on error or close */
-	RXRPC_CALL_LOCAL_ERROR,		/* - call failed due to local error */
-	RXRPC_CALL_NETWORK_ERROR,	/* - call terminated by network error */
-	NR__RXRPC_CALL_COMPLETIONS
-};
-
-/*
  * Call Tx congestion management modes.
  */
 enum rxrpc_congest_mode {
@@ -687,9 +676,15 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *,
 					 struct rxrpc_conn_parameters *,
 					 struct sockaddr_rxrpc *,
 					 unsigned long, s64, gfp_t);
+int rxrpc_retry_client_call(struct rxrpc_sock *,
+			    struct rxrpc_call *,
+			    struct rxrpc_conn_parameters *,
+			    struct sockaddr_rxrpc *,
+			    gfp_t);
 void rxrpc_incoming_call(struct rxrpc_sock *, struct rxrpc_call *,
 			 struct sk_buff *);
 void rxrpc_release_call(struct rxrpc_sock *, struct rxrpc_call *);
+int rxrpc_prepare_call_for_retry(struct rxrpc_sock *, struct rxrpc_call *);
 void rxrpc_release_calls_on_socket(struct rxrpc_sock *);
 bool __rxrpc_queue_call(struct rxrpc_call *);
 bool rxrpc_queue_call(struct rxrpc_call *);