g_union_wip
struct g_union_wip *wip, *waitingwip;
struct g_union_wip *wip;
static void g_union_doio(struct g_union_wip *wip);
g_union_doio(struct g_union_wip *wip)
struct g_union_wip *activewip;
TAILQ_HEAD(wiplist, g_union_wip);
TAILQ_ENTRY(g_union_wip) wip_next; /* pending or active I/O list */