QINV_ENTRY_SIZE
bcopy(dsc, qinv_table->qinv_mem_vaddr + tail * QINV_ENTRY_SIZE,
QINV_ENTRY_SIZE);
size = qinv->qinv_table.qinv_mem_size * QINV_ENTRY_SIZE;
+ (head * QINV_ENTRY_SIZE));