diff --git a/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c b/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c
index 40b41c794dfa..b3bc948d6145 100644
--- a/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c
+++ b/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c
@@ -52,10 +52,6 @@ static int hellcreek_set_hwtstamp_config(struct hellcreek *hellcreek, int port,
 	 */
 	clear_bit_unlock(HELLCREEK_HWTSTAMP_ENABLED, &ps->state);
 
-	/* Reserved for future extensions */
-	if (config->flags)
-		return -EINVAL;
-
 	switch (config->tx_type) {
 	case HWTSTAMP_TX_ON:
 		tx_tstamp_enable = true;
diff --git a/drivers/net/dsa/mv88e6xxx/hwtstamp.c b/drivers/net/dsa/mv88e6xxx/hwtstamp.c
index 8f74ffc7a279..389f8a6ec0ab 100644
--- a/drivers/net/dsa/mv88e6xxx/hwtstamp.c
+++ b/drivers/net/dsa/mv88e6xxx/hwtstamp.c
@@ -100,10 +100,6 @@ static int mv88e6xxx_set_hwtstamp_config(struct mv88e6xxx_chip *chip, int port,
 	 */
 	clear_bit_unlock(MV88E6XXX_HWTSTAMP_ENABLED, &ps->state);
 
-	/* reserved for future extensions */
-	if (config->flags)
-		return -EINVAL;
-
 	switch (config->tx_type) {
 	case HWTSTAMP_TX_OFF:
 		tstamp_enable = false;
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
index 30d24d19f40d..492ac383f16d 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
@@ -1508,9 +1508,6 @@ static int xgbe_set_hwtstamp_settings(struct xgbe_prv_data *pdata,
 	if (copy_from_user(&config, ifreq->ifr_data, sizeof(config)))
 		return -EFAULT;
 
-	if (config.flags)
-		return -EINVAL;
-
 	mac_tscr = 0;
 
 	switch (config.tx_type) {
diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_main.c b/drivers/net/ethernet/aquantia/atlantic/aq_main.c
index e22935ce9573..e65ce7199dac 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_main.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_main.c
@@ -231,9 +231,6 @@ static void aq_ndev_set_multicast_settings(struct net_device *ndev)
 static int aq_ndev_config_hwtstamp(struct aq_nic_s *aq_nic,
 				   struct hwtstamp_config *config)
 {
-	if (config->flags)
-		return -EINVAL;
-
 	switch (config->tx_type) {
 	case HWTSTAMP_TX_OFF:
 	case HWTSTAMP_TX_ON:
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
index aec666e97683..651bc1d7a57a 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
@@ -15356,11 +15356,6 @@ static int bnx2x_hwtstamp_ioctl(struct bnx2x *bp, struct ifreq *ifr)
 	DP(BNX2X_MSG_PTP, "Requested tx_type: %d, requested rx_filters = %d\n",
 	   config.tx_type, config.rx_filter);
 
-	if (config.flags) {
-		BNX2X_ERR("config.flags is reserved for future use\n");
-		return -EINVAL;
-	}
-
 	bp->hwtstamp_ioctl_called = true;
 	bp->tx_type = config.tx_type;
 	bp->rx_filter = config.rx_filter;
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
index 8388be119f9a..48520967746f 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
@@ -417,9 +417,6 @@ int bnxt_hwtstamp_set(struct net_device *dev, struct ifreq *ifr)
 	if (copy_from_user(&stmpconf, ifr->ifr_data, sizeof(stmpconf)))
 		return -EFAULT;
 
-	if (stmpconf.flags)
-		return -EINVAL;
-
 	if (stmpconf.tx_type != HWTSTAMP_TX_ON &&
 	    stmpconf.tx_type != HWTSTAMP_TX_OFF)
 		return -ERANGE;
diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 283f3c1f1195..c28f8cc00d1c 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -13806,9 +13806,6 @@ static int tg3_hwtstamp_set(struct net_device *dev, struct ifreq *ifr)
 	if (copy_from_user(&stmpconf, ifr->ifr_data, sizeof(stmpconf)))
 		return -EFAULT;
 
-	if (stmpconf.flags)
-		return -EINVAL;
-
 	if (stmpconf.tx_type != HWTSTAMP_TX_ON &&
 	    stmpconf.tx_type != HWTSTAMP_TX_OFF)
 		return -ERANGE;
diff --git a/drivers/net/ethernet/cadence/macb_ptp.c b/drivers/net/ethernet/cadence/macb_ptp.c
index 095c5a2144a7..fb6b27f46b15 100644
--- a/drivers/net/ethernet/cadence/macb_ptp.c
+++ b/drivers/net/ethernet/cadence/macb_ptp.c
@@ -464,10 +464,6 @@ int gem_set_hwtst(struct net_device *dev, struct ifreq *ifr, int cmd)
 			   sizeof(*tstamp_config)))
 		return -EFAULT;
 
-	/* reserved for future extensions */
-	if (tstamp_config->flags)
-		return -EINVAL;
-
 	switch (tstamp_config->tx_type) {
 	case HWTSTAMP_TX_OFF:
 		break;
diff --git a/drivers/net/ethernet/cavium/liquidio/lio_main.c b/drivers/net/ethernet/cavium/liquidio/lio_main.c
index 12eee2bc7f5c..ba28aa444e5a 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_main.c
@@ -2114,9 +2114,6 @@ static int hwtstamp_ioctl(struct net_device *netdev, struct ifreq *ifr)
 	if (copy_from_user(&conf, ifr->ifr_data, sizeof(conf)))
 		return -EFAULT;
 
-	if (conf.flags)
-		return -EINVAL;
-
 	switch (conf.tx_type) {
 	case HWTSTAMP_TX_ON:
 	case HWTSTAMP_TX_OFF:
diff --git a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
index c607756b731f..568f211d91cc 100644
--- a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
+++ b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
@@ -1254,9 +1254,6 @@ static int hwtstamp_ioctl(struct net_device *netdev, struct ifreq *ifr)
 	if (copy_from_user(&conf, ifr->ifr_data, sizeof(conf)))
 		return -EFAULT;
 
-	if (conf.flags)
-		return -EINVAL;
-
 	switch (conf.tx_type) {
 	case HWTSTAMP_TX_ON:
 	case HWTSTAMP_TX_OFF:
diff --git a/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c b/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
index 4b4ffdd1044d..103591dcea1c 100644
--- a/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
+++ b/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
@@ -702,9 +702,6 @@ static int octeon_mgmt_ioctl_hwtstamp(struct net_device *netdev,
 	if (copy_from_user(&config, rq->ifr_data, sizeof(config)))
 		return -EFAULT;
 
-	if (config.flags) /* reserved for future extensions */
-		return -EINVAL;
-
 	/* Check the status of hardware for tiemstamps */
 	if (OCTEON_IS_MODEL(OCTEON_CN6XXX)) {
 		/* Get the current state of the PTP clock */
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
index bb45d5df2856..63191692f624 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
@@ -1917,10 +1917,6 @@ static int nicvf_config_hwtstamp(struct net_device *netdev, struct ifreq *ifr)
 	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
 		return -EFAULT;
 
-	/* reserved for future extensions */
-	if (config.flags)
-		return -EINVAL;
-
 	switch (config.tx_type) {
 	case HWTSTAMP_TX_OFF:
 	case HWTSTAMP_TX_ON:
diff --git a/drivers/net/ethernet/engleder/tsnep_ptp.c b/drivers/net/ethernet/engleder/tsnep_ptp.c
index 4bfb4d8508f5..eaad453d487e 100644
--- a/drivers/net/ethernet/engleder/tsnep_ptp.c
+++ b/drivers/net/ethernet/engleder/tsnep_ptp.c
@@ -31,9 +31,6 @@ int tsnep_ptp_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
 		if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
 			return -EFAULT;
 
-		if (config.flags)
-			return -EINVAL;
-
 		switch (config.tx_type) {
 		case HWTSTAMP_TX_OFF:
 		case HWTSTAMP_TX_ON:
diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c
index d71eac7e1924..af99017a5453 100644
--- a/drivers/net/ethernet/freescale/fec_ptp.c
+++ b/drivers/net/ethernet/freescale/fec_ptp.c
@@ -473,10 +473,6 @@ int fec_ptp_set(struct net_device *ndev, struct ifreq *ifr)
 	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
 		return -EFAULT;
 
-	/* reserved for future extensions */
-	if (config.flags)
-		return -EINVAL;
-
 	switch (config.tx_type) {
 	case HWTSTAMP_TX_OFF:
 		fep->hwts_tx_en = 0;
diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index acab58fd3db3..206b7a35eaf5 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c
@@ -2076,10 +2076,6 @@ static int gfar_hwtstamp_set(struct net_device *netdev, struct ifreq *ifr)
 	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
 		return -EFAULT;
 
-	/* reserved for future extensions */
-	if (config.flags)
-		return -EINVAL;
-
 	switch (config.tx_type) {
 	case HWTSTAMP_TX_OFF:
 		priv->hwts_tx_en = 0;
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 44e2dc8328a2..635a95927e93 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -3614,10 +3614,6 @@ static int e1000e_config_hwtstamp(struct e1000_adapter *adapter,
 	if (!(adapter->flags & FLAG_HAS_HW_TIMESTAMP))
 		return -EINVAL;
 
-	/* flags reserved for future extensions - must be zero */
-	if (config->flags)
-		return -EINVAL;
-
 	switch (config->tx_type) {
 	case HWTSTAMP_TX_OFF:
 		tsync_tx_ctl = 0;
diff --git a/drivers/net/ethernet/intel/i40e/i40e_ptp.c b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
index 09b1d5aed1c9..61e5789d78db 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ptp.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ptp.c
@@ -1205,10 +1205,6 @@ static int i40e_ptp_set_timestamp_mode(struct i40e_pf *pf,
 
 	INIT_WORK(&pf->ptp_extts0_work, i40e_ptp_extts0_work);
 
-	/* Reserved for future extensions. */
-	if (config->flags)
-		return -EINVAL;
-
 	switch (config->tx_type) {
 	case HWTSTAMP_TX_OFF:
 		pf->ptp_tx = false;
diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
index bf7247c6f58e..dfc7c830acf6 100644
--- a/drivers/net/ethernet/intel/ice/ice_ptp.c
+++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
@@ -1205,10 +1205,6 @@ int ice_ptp_get_ts_config(struct ice_pf *pf, struct ifreq *ifr)
 static int
 ice_ptp_set_timestamp_mode(struct ice_pf *pf, struct hwtstamp_config *config)
 {
-	/* Reserved for future extensions. */
-	if (config->flags)
-		return -EINVAL;
-
 	switch (config->tx_type) {
 	case HWTSTAMP_TX_OFF:
 		ice_set_tx_tstamp(pf, false);
diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c
index 0011b15e678c..0ac4cc5eaa2d 100644
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -1015,10 +1015,6 @@ static int igb_ptp_set_timestamp_mode(struct igb_adapter *adapter,
 	bool is_l2 = false;
 	u32 regval;
 
-	/* reserved for future extensions */
-	if (config->flags)
-		return -EINVAL;
-
 	switch (config->tx_type) {
 	case HWTSTAMP_TX_OFF:
 		tsync_tx_ctl = 0;
diff --git a/drivers/net/ethernet/intel/igc/igc_ptp.c b/drivers/net/ethernet/intel/igc/igc_ptp.c
index 30568e3544cd..71813fa8f928 100644
--- a/drivers/net/ethernet/intel/igc/igc_ptp.c
+++ b/drivers/net/ethernet/intel/igc/igc_ptp.c
@@ -560,10 +560,6 @@ static void igc_ptp_enable_tx_timestamp(struct igc_adapter *adapter)
 static int igc_ptp_set_timestamp_mode(struct igc_adapter *adapter,
 				      struct hwtstamp_config *config)
 {
-	/* reserved for future extensions */
-	if (config->flags)
-		return -EINVAL;
-
 	switch (config->tx_type) {
 	case HWTSTAMP_TX_OFF:
 		igc_ptp_disable_tx_timestamp(adapter);
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
index 23ddfd79fc8b..336426a67ac1 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c
@@ -992,10 +992,6 @@ static int ixgbe_ptp_set_timestamp_mode(struct ixgbe_adapter *adapter,
 	bool is_l2 = false;
 	u32 regval;
 
-	/* reserved for future extensions */
-	if (config->flags)
-		return -EINVAL;
-
 	switch (config->tx_type) {
 	case HWTSTAMP_TX_OFF:
 		tsync_tx_ctl = 0;
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
index 8e5820d12362..b1cce4425296 100644
--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -5142,9 +5142,6 @@ static int mvpp2_set_ts_config(struct mvpp2_port *port, struct ifreq *ifr)
 	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
 		return -EFAULT;
 
-	if (config.flags)
-		return -EINVAL;
-
 	if (config.tx_type != HWTSTAMP_TX_OFF &&
 	    config.tx_type != HWTSTAMP_TX_ON)
 		return -ERANGE;
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
index 1333edf1c361..6080ebd9bd94 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c
@@ -2002,10 +2002,6 @@ int otx2_config_hwtstamp(struct net_device *netdev, struct ifreq *ifr)
 	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
 		return -EFAULT;
 
-	/* reserved for future extensions */
-	if (config.flags)
-		return -EINVAL;
-
 	switch (config.tx_type) {
 	case HWTSTAMP_TX_OFF:
 		otx2_config_hw_tx_tstamp(pfvf, false);
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
index f1c10f2bda78..ad1e4caf48bf 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_netdev.c
@@ -2427,10 +2427,6 @@ static int mlx4_en_hwtstamp_set(struct net_device *dev, struct ifreq *ifr)
 	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
 		return -EFAULT;
 
-	/* reserved for future extensions */
-	if (config.flags)
-		return -EINVAL;
-
 	/* device doesn't support time stamping */
 	if (!(mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_TS))
 		return -EINVAL;
diff --git a/drivers/net/ethernet/microchip/lan743x_ptp.c b/drivers/net/ethernet/microchip/lan743x_ptp.c
index 9380e396f648..8b7a8d879083 100644
--- a/drivers/net/ethernet/microchip/lan743x_ptp.c
+++ b/drivers/net/ethernet/microchip/lan743x_ptp.c
@@ -1305,12 +1305,6 @@ int lan743x_ptp_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
 	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
 		return -EFAULT;
 
-	if (config.flags) {
-		netif_warn(adapter, drv, adapter->netdev,
-			   "ignoring hwtstamp_config.flags == 0x%08X, expected 0\n",
-			   config.flags);
-	}
-
 	switch (config.tx_type) {
 	case HWTSTAMP_TX_OFF:
 		for (index = 0; index < LAN743X_MAX_TX_CHANNELS;
diff --git a/drivers/net/ethernet/mscc/ocelot.c b/drivers/net/ethernet/mscc/ocelot.c
index 876a7ecf86eb..9b42187a026a 100644
--- a/drivers/net/ethernet/mscc/ocelot.c
+++ b/drivers/net/ethernet/mscc/ocelot.c
@@ -1617,10 +1617,6 @@ int ocelot_hwstamp_set(struct ocelot *ocelot, int port, struct ifreq *ifr)
 	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
 		return -EFAULT;
 
-	/* reserved for future extensions */
-	if (cfg.flags)
-		return -EINVAL;
-
 	/* Tx type sanity check */
 	switch (cfg.tx_type) {
 	case HWTSTAMP_TX_ON:
diff --git a/drivers/net/ethernet/neterion/vxge/vxge-main.c b/drivers/net/ethernet/neterion/vxge/vxge-main.c
index 1969009a91e7..2c2e9e56ed4e 100644
--- a/drivers/net/ethernet/neterion/vxge/vxge-main.c
+++ b/drivers/net/ethernet/neterion/vxge/vxge-main.c
@@ -3159,10 +3159,6 @@ static int vxge_hwtstamp_set(struct vxgedev *vdev, void __user *data)
 	if (copy_from_user(&config, data, sizeof(config)))
 		return -EFAULT;
 
-	/* reserved for future extensions */
-	if (config.flags)
-		return -EINVAL;
-
 	/* Transmit HW Timestamp not supported */
 	switch (config.tx_type) {
 	case HWTSTAMP_TX_OFF:
diff --git a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
index 71d234291fc5..1dc40c537281 100644
--- a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
+++ b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
@@ -210,9 +210,6 @@ static int hwtstamp_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
 	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
 		return -EFAULT;
 
-	if (cfg.flags) /* reserved for future extensions */
-		return -EINVAL;
-
 	/* Get ieee1588's dev information */
 	pdev = adapter->ptp_pdev;
 
diff --git a/drivers/net/ethernet/qlogic/qede/qede_ptp.c b/drivers/net/ethernet/qlogic/qede/qede_ptp.c
index 8c28fabb0ff6..39176e765767 100644
--- a/drivers/net/ethernet/qlogic/qede/qede_ptp.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_ptp.c
@@ -304,11 +304,6 @@ int qede_ptp_hw_ts(struct qede_dev *edev, struct ifreq *ifr)
 		   "HWTSTAMP IOCTL: Requested tx_type = %d, requested rx_filters = %d\n",
 		   config.tx_type, config.rx_filter);
 
-	if (config.flags) {
-		DP_ERR(edev, "config.flags is reserved for future use\n");
-		return -EINVAL;
-	}
-
 	ptp->hw_ts_ioctl_called = 1;
 	ptp->tx_type = config.tx_type;
 	ptp->rx_filter = config.rx_filter;
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index ce09bd45527e..b215cde68e10 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -2221,10 +2221,6 @@ static int ravb_hwtstamp_set(struct net_device *ndev, struct ifreq *req)
 	if (copy_from_user(&config, req->ifr_data, sizeof(config)))
 		return -EFAULT;
 
-	/* Reserved for future extensions */
-	if (config.flags)
-		return -EINVAL;
-
 	switch (config.tx_type) {
 	case HWTSTAMP_TX_OFF:
 		tstamp_tx_ctrl = 0;
diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c
index 797e51802ccb..f0ef515e2ade 100644
--- a/drivers/net/ethernet/sfc/ptp.c
+++ b/drivers/net/ethernet/sfc/ptp.c
@@ -1765,9 +1765,6 @@ static int efx_ptp_ts_init(struct efx_nic *efx, struct hwtstamp_config *init)
 {
 	int rc;
 
-	if (init->flags)
-		return -EINVAL;
-
 	if ((init->tx_type != HWTSTAMP_TX_OFF) &&
 	    (init->tx_type != HWTSTAMP_TX_ON))
 		return -ERANGE;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 7e3e1bc0f61d..c26ac288f981 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -638,10 +638,6 @@ static int stmmac_hwtstamp_set(struct net_device *dev, struct ifreq *ifr)
 	netdev_dbg(priv->dev, "%s config flags:0x%x, tx_type:0x%x, rx_filter:0x%x\n",
 		   __func__, config.flags, config.tx_type, config.rx_filter);
 
-	/* reserved for future extensions */
-	if (config.flags)
-		return -EINVAL;
-
 	if (config.tx_type != HWTSTAMP_TX_OFF &&
 	    config.tx_type != HWTSTAMP_TX_ON)
 		return -ERANGE;
diff --git a/drivers/net/ethernet/ti/cpsw_priv.c b/drivers/net/ethernet/ti/cpsw_priv.c
index c99dd9735087..8624a044776f 100644
--- a/drivers/net/ethernet/ti/cpsw_priv.c
+++ b/drivers/net/ethernet/ti/cpsw_priv.c
@@ -626,10 +626,6 @@ static int cpsw_hwtstamp_set(struct net_device *dev, struct ifreq *ifr)
 	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
 		return -EFAULT;
 
-	/* reserved for future extensions */
-	if (cfg.flags)
-		return -EINVAL;
-
 	if (cfg.tx_type != HWTSTAMP_TX_OFF && cfg.tx_type != HWTSTAMP_TX_ON)
 		return -ERANGE;
 
diff --git a/drivers/net/ethernet/ti/netcp_ethss.c b/drivers/net/ethernet/ti/netcp_ethss.c
index 33c1592d5381..751fb0bc65c5 100644
--- a/drivers/net/ethernet/ti/netcp_ethss.c
+++ b/drivers/net/ethernet/ti/netcp_ethss.c
@@ -2654,10 +2654,6 @@ static int gbe_hwtstamp_set(struct gbe_intf *gbe_intf, struct ifreq *ifr)
 	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
 		return -EFAULT;
 
-	/* reserved for future extensions */
-	if (cfg.flags)
-		return -EINVAL;
-
 	switch (cfg.tx_type) {
 	case HWTSTAMP_TX_OFF:
 		gbe_dev->tx_ts_enabled = 0;
diff --git a/drivers/net/ethernet/xscale/ixp4xx_eth.c b/drivers/net/ethernet/xscale/ixp4xx_eth.c
index 65fdad1107fc..df77a22d1b81 100644
--- a/drivers/net/ethernet/xscale/ixp4xx_eth.c
+++ b/drivers/net/ethernet/xscale/ixp4xx_eth.c
@@ -382,9 +382,6 @@ static int hwtstamp_set(struct net_device *netdev, struct ifreq *ifr)
 	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
 		return -EFAULT;
 
-	if (cfg.flags) /* reserved for future extensions */
-		return -EINVAL;
-
 	ret = ixp46x_ptp_find(&port->timesync_regs, &port->phc_index);
 	if (ret)
 		return ret;
diff --git a/drivers/net/phy/dp83640.c b/drivers/net/phy/dp83640.c
index 705c16675b80..c2d1a85ec559 100644
--- a/drivers/net/phy/dp83640.c
+++ b/drivers/net/phy/dp83640.c
@@ -1235,9 +1235,6 @@ static int dp83640_hwtstamp(struct mii_timestamper *mii_ts, struct ifreq *ifr)
 	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
 		return -EFAULT;
 
-	if (cfg.flags) /* reserved for future extensions */
-		return -EINVAL;
-
 	if (cfg.tx_type < 0 || cfg.tx_type > HWTSTAMP_TX_ONESTEP_SYNC)
 		return -ERANGE;
 
diff --git a/drivers/net/phy/mscc/mscc_ptp.c b/drivers/net/phy/mscc/mscc_ptp.c
index edb951695b13..34f829845d06 100644
--- a/drivers/net/phy/mscc/mscc_ptp.c
+++ b/drivers/net/phy/mscc/mscc_ptp.c
@@ -1057,9 +1057,6 @@ static int vsc85xx_hwtstamp(struct mii_timestamper *mii_ts, struct ifreq *ifr)
 	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
 		return -EFAULT;
 
-	if (cfg.flags)
-		return -EINVAL;
-
 	switch (cfg.tx_type) {
 	case HWTSTAMP_TX_ONESTEP_SYNC:
 		one_step = true;
diff --git a/drivers/ptp/ptp_ines.c b/drivers/ptp/ptp_ines.c
index 6c7c2843ba0b..61f47fb9d997 100644
--- a/drivers/ptp/ptp_ines.c
+++ b/drivers/ptp/ptp_ines.c
@@ -338,10 +338,6 @@ static int ines_hwtstamp(struct mii_timestamper *mii_ts, struct ifreq *ifr)
 	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
 		return -EFAULT;
 
-	/* reserved for future extensions */
-	if (cfg.flags)
-		return -EINVAL;
-
 	switch (cfg.tx_type) {
 	case HWTSTAMP_TX_OFF:
 		ts_stat_tx = 0;
diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h
index fcc61c73a666..e258e52cfd1f 100644
--- a/include/uapi/linux/net_tstamp.h
+++ b/include/uapi/linux/net_tstamp.h
@@ -62,7 +62,7 @@ struct so_timestamping {
 /**
  * struct hwtstamp_config - %SIOCGHWTSTAMP and %SIOCSHWTSTAMP parameter
  *
- * @flags:	no flags defined right now, must be zero for %SIOCSHWTSTAMP
+ * @flags:	one of HWTSTAMP_FLAG_*
  * @tx_type:	one of HWTSTAMP_TX_*
  * @rx_filter:	one of HWTSTAMP_FILTER_*
  *
@@ -78,6 +78,20 @@ struct hwtstamp_config {
 	int rx_filter;
 };
 
+/* possible values for hwtstamp_config->flags */
+enum hwtstamp_flags {
+	/*
+	 * With this flag, the user could get bond active interface's
+	 * PHC index. Note this PHC index is not stable as when there
+	 * is a failover, the bond active interface will be changed, so
+	 * will be the PHC index.
+	 */
+	HWTSTAMP_FLAG_BONDED_PHC_INDEX = (1<<0),
+
+	HWTSTAMP_FLAG_LAST = HWTSTAMP_FLAG_BONDED_PHC_INDEX,
+	HWTSTAMP_FLAG_MASK = (HWTSTAMP_FLAG_LAST - 1) | HWTSTAMP_FLAG_LAST
+};
+
 /* possible values for hwtstamp_config->tx_type */
 enum hwtstamp_tx_types {
 	/*
diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c
index 1d309a666932..1b807d119da5 100644
--- a/net/core/dev_ioctl.c
+++ b/net/core/dev_ioctl.c
@@ -192,7 +192,7 @@ static int net_hwtstamp_validate(struct ifreq *ifr)
 	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
 		return -EFAULT;
 
-	if (cfg.flags) /* reserved for future extensions */
+	if (cfg.flags & ~HWTSTAMP_FLAG_MASK)
 		return -EINVAL;
 
 	tx_type = cfg.tx_type;