PCI_SYNC_FLAG_SZSHIFT
sync_flag_pa >>= PCI_SYNC_FLAG_SZSHIFT;
sync_flag_pa <<= PCI_SYNC_FLAG_SZSHIFT;
#define PCI_SYNC_FLAG_SIZE (1 << PCI_SYNC_FLAG_SZSHIFT)
((flow_p)->flow_buf_pa + ((flow_id) << PCI_SYNC_FLAG_SZSHIFT))