I caught one during a review and figured I might as well sweep the whole
tree, so this patch was created using Coccinelle and the following steps:

    $ cat >check_obj.cocci <<EOF
    @@
    expression obj, magic;
    @@

    if (obj != NULL) {
    - CHECK_OBJ_NOTNULL(obj, magic);
    + CHECK_OBJ(obj, magic);
    ...
    }
    EOF
    $ spatch --dir . --in-place --sp-file check_obj.cocci

This is my fourth semantic patch, I wouldn't mind checking them in to
have them handy in the repo to semi-automate code polish every now and
then. For example in a /tools/cocci directory. This way people could
study them or use them in their out-of-tree projects like VMODs or VUTs.