[PATCH 2/3] NFS: Partially revert commit 845cbceb

[Chuck Lever <chuck.lever@oracle.com>]

I'm about to add logic that invokes nfs4_clear_machine_cred(), but
we removed it in 3.10.  This is a separate commit to make it easier
to backport the next patch to a kernel that may still have
nfs4_clear_machine_cred().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfs/nfs4state.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 1fab140..4949ce5 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -154,6 +154,18 @@ struct rpc_cred *nfs4_get_machine_cred_locked(struct nfs_client *clp)
 	return cred;
 }
 
+static void nfs4_clear_machine_cred(struct nfs_client *clp)
+{
+	struct rpc_cred *cred;
+
+	spin_lock(&clp->cl_lock);
+	cred = clp->cl_machine_cred;
+	clp->cl_machine_cred = NULL;
+	spin_unlock(&clp->cl_lock);
+	if (cred != NULL)
+		put_rpccred(cred);
+}
+
 static struct rpc_cred *
 nfs4_get_renew_cred_server_locked(struct nfs_server *server)
 {