IDPF_VC_XN_RING_LEN
struct idpf_vc_xn ring[IDPF_VC_XN_RING_LEN];
DECLARE_BITMAP(free_xn_bm, IDPF_VC_XN_RING_LEN);
bitmap_fill(vcxn_mngr->free_xn_bm, IDPF_VC_XN_RING_LEN);
bitmap_zero(vcxn_mngr->free_xn_bm, IDPF_VC_XN_RING_LEN);
free_idx = find_first_bit(vcxn_mngr->free_xn_bm, IDPF_VC_XN_RING_LEN);
if (free_idx == IDPF_VC_XN_RING_LEN)