nfsd: lift NFSv4.0 handling out of nfsd4_cb_sequence_done()

It's a bit strange to call nfsd4_cb_sequence_done() on a callback with no
CB_SEQUENCE. Lift the handling of restarting a call into a new helper,
and move the handling of NFSv4.0 into nfsd4_cb_done().

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Author: jtlayton

fs/nfsd/nfs4callback.c

@@ -1064,6 +1064,17 @@ static bool nfsd4_queue_cb(struct nfsd4_callback *cb)
 	return queue_work(clp->cl_callback_wq, &cb->cb_work);
 }
 
+static void nfsd4_requeue_cb(struct rpc_task *task, struct nfsd4_callback *cb)
+{
+	struct nfs4_client *clp = cb->cb_clp;
+
+	if (!test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags)) {
+		trace_nfsd_cb_restart(clp, cb);
+		task->tk_status = 0;
+		cb->cb_need_restart = true;
+	}
+}
+
 static void nfsd41_cb_inflight_begin(struct nfs4_client *clp)
 {
 	atomic_inc(&clp->cl_cb_inflight);
@@ -1331,26 +1342,9 @@ static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
 /* Returns true if CB_COMPOUND processing should continue */
 static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback *cb)
 {
-	struct nfs4_client *clp = cb->cb_clp;
-	struct nfsd4_session *session = clp->cl_cb_session;
+	struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
 	bool ret = false;
 
-	if (!clp->cl_minorversion) {
-		/*
-		 * If the backchannel connection was shut down while this
-		 * task was queued, we need to resubmit it after setting up
-		 * a new backchannel connection.
-		 *
-		 * Note that if we lost our callback connection permanently
-		 * the submission code will error out, so we don't need to
-		 * handle that case here.
-		 */
-		if (RPC_SIGNALLED(task))
-			goto requeue;
-
-		return true;
-	}
-
 	if (cb->cb_held_slot < 0)
 		goto requeue;
 
@@ -1411,11 +1405,7 @@ static bool nfsd4_cb_sequence_done(struct rpc_task *task, struct nfsd4_callback
 	rpc_restart_call_prepare(task);
 	goto out;
 requeue:
-	if (!test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags)) {
-		trace_nfsd_cb_restart(clp, cb);
-		task->tk_status = 0;
-		cb->cb_need_restart = true;
-	}
+	nfsd4_requeue_cb(task, cb);
 	return false;
 }
 
@@ -1426,8 +1416,21 @@ static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
 
 	trace_nfsd_cb_rpc_done(clp);
 
-	if (!nfsd4_cb_sequence_done(task, cb))
+	if (!clp->cl_minorversion) {
+		/*
+		 * If the backchannel connection was shut down while this
+		 * task was queued, we need to resubmit it after setting up
+		 * a new backchannel connection.
+		 *
+		 * Note that if we lost our callback connection permanently
+		 * the submission code will error out, so we don't need to
+		 * handle that case here.
+		 */
+		if (RPC_SIGNALLED(task))
+			nfsd4_requeue_cb(task, cb);
+	} else if (!nfsd4_cb_sequence_done(task, cb)) {
 		return;
+	}
 
 	if (cb->cb_status) {
 		WARN_ONCE(task->tk_status,