void netif_napi_add(struct net_device *dev, struct napi_struct *napi,
int (*poll)(struct napi_struct *, int), int weight)
function like this could not be located by cscope via defintion.
ctags could locate this kind function definiton.
I want to use cscope only, if cscope could also find such tags.
The answer to your question is in last paragraph of the cscope manpage, which see.