IWM_NUM_OF_TBS
IWM_NUM_OF_TBS - 2, mapsize, 0, BUS_DMA_NOWAIT,
struct mbuf* m1 = m_collapse(m, M_NOWAIT, IWM_NUM_OF_TBS - 2);
struct iwm_tfd_tb tbs[IWM_NUM_OF_TBS];