HPSA_SG_LAST
cp->SG[0].Ext = cpu_to_le32(HPSA_SG_LAST); /* we are not chaining */
(curr_sg - 1)->Ext = cpu_to_le32(HPSA_SG_LAST);
(--curr_sg)->Ext = cpu_to_le32(HPSA_SG_LAST);
c->SG[0].Ext = cpu_to_le32(HPSA_SG_LAST); /* not chaining */
c->SG[--i].Ext = cpu_to_le32(HPSA_SG_LAST);