SUNRPC: Add a flag to avoid reference counts on credentials

Add a flag to signal to the RPC layer that the credential is already
pinned for the duration of the RPC call.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 55e9002..6eff141 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -1162,7 +1162,8 @@ static void rpc_release_resources_task(struct rpc_task *task)
 {
 	xprt_release(task);
 	if (task->tk_msg.rpc_cred) {
-		put_cred(task->tk_msg.rpc_cred);
+		if (!(task->tk_flags & RPC_TASK_CRED_NOREF))
+			put_cred(task->tk_msg.rpc_cred);
 		task->tk_msg.rpc_cred = NULL;
 	}
 	rpc_task_release_client(task);