null: make *impl_ private

This can/should be private, given struct is default public in C++.
The null ioengine only needs access to new'd NullData which
encapsulates malloc'd null_data *impl_.

Signed-off-by: Tomohiro Kusumi <tkusumi@tuxera.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/engines/null.c b/engines/null.c
index 47f290548ceafb39763b9bfd5cf08a29aa7f2e06..cf1ee1f2e433cd92836725d991c849e70769a991 100644 (file)
--- a/engines/null.c
+++ b/engines/null.c
@@ -213,6 +213,7 @@ struct NullData {
                return null_open(impl_, f);
        }
 
+private:
        struct null_data *impl_;
 };