rxrpc: Support service upgrade from a kernel service

Provide support for a kernel service to make use of the service upgrade
facility.  This involves:

 (1) Pass an upgrade request flag to rxrpc_kernel_begin_call().

 (2) Make rxrpc_kernel_recv_data() return the call's current service ID so
     that the caller can detect service upgrade and see what the service
     was upgraded to.

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

1 files changed, 4 insertions, 1 deletions

diff --git a/net/rxrpc/recvmsg.c b/net/rxrpc/recvmsg.c
index bdece21f313d..e4937b3f3685 100644
--- a/net/rxrpc/recvmsg.c
+++ b/net/rxrpc/recvmsg.c
@@ -607,6 +607,7 @@ wait_error:
  * @_offset: The running offset into the buffer.
  * @want_more: True if more data is expected to be read
  * @_abort: Where the abort code is stored if -ECONNABORTED is returned
+ * @_service: Where to store the actual service ID (may be upgraded)
  *
  * Allow a kernel service to receive data and pick up information about the
  * state of a call.  Returns 0 if got what was asked for and there's more
@@ -624,7 +625,7 @@ wait_error:
  */
 int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
 			   void *buf, size_t size, size_t *_offset,
-			   bool want_more, u32 *_abort)
+			   bool want_more, u32 *_abort, u16 *_service)
 {
 	struct iov_iter iter;
 	struct kvec iov;
@@ -680,6 +681,8 @@ int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
 read_phase_complete:
 	ret = 1;
 out:
+	if (_service)
+		*_service = call->service_id;
 	mutex_unlock(&call->user_mutex);
 	_leave(" = %d [%zu,%d]", ret, *_offset, *_abort);
 	return ret;