request_cmp
SPLAY_GENERATE(reqtree, request, entry, request_cmp);
static int request_cmp(struct request *, struct request *);
SPLAY_PROTOTYPE(reqtree, request, entry, request_cmp);
SPLAY_GENERATE(reqtree, request, entry, request_cmp);
static int request_cmp(struct request *, struct request *);
SPLAY_PROTOTYPE(reqtree, request, entry, request_cmp);