nfsd: constify nfsd4_callback_ops structure

The nfsd4_callback_ops structure is never modified, so declare it as const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 77fdf4d..5e2ba19 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -65,7 +65,7 @@
 	struct nfs4_client *cb_clp;
 	u32 cb_minorversion;
 	struct rpc_message cb_msg;
-	struct nfsd4_callback_ops *cb_ops;
+	const struct nfsd4_callback_ops *cb_ops;
 	struct work_struct cb_work;
 	int cb_seq_status;
 	int cb_status;
@@ -599,7 +599,7 @@
 extern void nfsd4_probe_callback_sync(struct nfs4_client *clp);
 extern void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *);
 extern void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
-		struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op);
+		const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op);
 extern void nfsd4_run_cb(struct nfsd4_callback *cb);
 extern int nfsd4_create_callback_queue(void);
 extern void nfsd4_destroy_callback_queue(void);