I've been learning c++ for a while. Recently I saw a format of passing function parameters. It looks like this

typedef struct LNode {
    int data;
    struct LNode* next;
} LNode, *LinkList;

bool insertData(LinkList &L, int i){
    cout <<  l;
    return false;
}

I know that LinkList is equivalent to LNode* which means a head pointer. But what does LinkList & aka LNode* & mean under the circumstances?

It seems to me that passing a LNode* aka LinkList would be enough.