net: annotate writes on dev->mtu from ndo_change_mtu()

Simon reported that ndo_change_mtu() methods were never
updated to use WRITE_ONCE(dev->mtu, new_mtu) as hinted
in commit 501a90c94510 ("inet: protect against too small
mtu values.")

We read dev->mtu without holding RTNL in many places,
with READ_ONCE() annotations.

It is time to take care of ndo_change_mtu() methods
to use corresponding WRITE_ONCE()

Signed-off-by: Eric Dumazet <[e-mail]>
Reported-by: Simon Horman <[e-mail]>
Closes: https://lore.kernel.org/netdev/[e-mail]/
Reviewed-by: Jacob Keller <[e-mail]>
Reviewed-by: Sabrina Dubroca <[e-mail]>
Reviewed-by: Simon Horman <[e-mail]>
Acked-by: Shannon Nelson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/infiniband/ulp/ipoib/ipoib_main.c

···
 			ipoib_warn(priv, "mtu > %d will cause multicast packet drops.\n",
 				   priv->mcast_mtu);
 
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 		return 0;
 	}
 
···
 		if (carrier_status)
 			netif_carrier_on(dev);
 	} else {
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 	}
 
 	return ret;

drivers/net/bonding/bond_main.c

···
 		}
 	}
 
-	bond_dev->mtu = new_mtu;
+	WRITE_ONCE(bond_dev->mtu, new_mtu);
 
 	return 0;
 

drivers/net/can/dev/dev.c

···
 		return -EINVAL;
 	}
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(can_change_mtu);

drivers/net/can/vcan.c

···
 	    !can_is_canxl_dev_mtu(new_mtu))
 		return -EINVAL;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/can/vxcan.c

···
 	    !can_is_canxl_dev_mtu(new_mtu))
 		return -EINVAL;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/ethernet/agere/et131x.c

···
 
 	et131x_disable_txrx(netdev);
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	et131x_adapter_memory_free(adapter);
 

drivers/net/ethernet/alteon/acenic.c

···
 	struct ace_regs __iomem *regs = ap->regs;
 
 	writel(new_mtu + ETH_HLEN + 4, &regs->IfMtu);
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	if (new_mtu > ACE_STD_MTU) {
 		if (!(ap->jumbo)) {

drivers/net/ethernet/altera/altera_tse_main.c

···
 		return -EBUSY;
 	}
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	netdev_update_features(dev);
 
 	return 0;

drivers/net/ethernet/amazon/ena/ena_netdev.c

···
 	if (!ret) {
 		netif_dbg(adapter, drv, dev, "Set MTU to %d\n", new_mtu);
 		update_rx_ring_mtu(adapter, new_mtu);
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 	} else {
 		netif_err(adapter, drv, dev, "Failed to set MTU to %d\n",
 			  new_mtu);

drivers/net/ethernet/amd/amd8111e.c

···
 
 	if (!netif_running(dev)) {
 		/* new_mtu will be used
-		 * when device starts netxt time
+		 * when device starts next time
 		 */
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 		return 0;
 	}
 
···
 	/* stop the chip */
 	writel(RUN, lp->mmio + CMD0);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	err = amd8111e_restart(dev);
 	spin_unlock_irq(&lp->lock);

drivers/net/ethernet/amd/xgbe/xgbe-drv.c

···
 		return ret;
 
 	pdata->rx_buf_size = ret;
-	netdev->mtu = mtu;
+	WRITE_ONCE(netdev->mtu, mtu);
 
 	xgbe_restart_dev(pdata);
 

drivers/net/ethernet/apm/xgene/xgene_enet_main.c

···
 	frame_size = (new_mtu > ETH_DATA_LEN) ? (new_mtu + 18) : 0x600;
 
 	xgene_enet_close(ndev);
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 	pdata->mac_ops->set_framesize(pdata, frame_size);
 	xgene_enet_open(ndev);
 

drivers/net/ethernet/aquantia/atlantic/aq_main.c

···
 
 	if (err < 0)
 		goto err_exit;
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 
 err_exit:
 	return err;

drivers/net/ethernet/atheros/ag71xx.c

···
 {
 	struct ag71xx *ag = netdev_priv(ndev);
 
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 	ag71xx_wr(ag, AG71XX_REG_MAC_MFL,
 		  ag71xx_max_frame_len(ndev->mtu));
 

drivers/net/ethernet/atheros/alx/main.c

···
 	struct alx_priv *alx = netdev_priv(netdev);
 	int max_frame = ALX_MAX_FRAME_LEN(mtu);
 
-	netdev->mtu = mtu;
+	WRITE_ONCE(netdev->mtu, mtu);
 	alx->hw.mtu = mtu;
 	alx->rxbuf_size = max(max_frame, ALX_DEF_RXBUF_SIZE);
 	netdev_update_features(netdev);

drivers/net/ethernet/atheros/atl1c/atl1c_main.c

···
 	if (netif_running(netdev)) {
 		while (test_and_set_bit(__AT_RESETTING, &adapter->flags))
 			msleep(1);
-		netdev->mtu = new_mtu;
+		WRITE_ONCE(netdev->mtu, new_mtu);
 		adapter->hw.max_frame_size = new_mtu;
 		atl1c_set_rxbufsize(adapter, netdev);
 		atl1c_down(adapter);

drivers/net/ethernet/atheros/atl1e/atl1e_main.c

···
 	if (netif_running(netdev)) {
 		while (test_and_set_bit(__AT_RESETTING, &adapter->flags))
 			msleep(1);
-		netdev->mtu = new_mtu;
+		WRITE_ONCE(netdev->mtu, new_mtu);
 		adapter->hw.max_frame_size = new_mtu;
 		adapter->hw.rx_jumbo_th = (max_frame + 7) >> 3;
 		atl1e_down(adapter);

drivers/net/ethernet/atheros/atlx/atl1.c

···
 	adapter->rx_buffer_len = (max_frame + 7) & ~7;
 	adapter->hw.rx_jumbo_th = adapter->rx_buffer_len / 8;
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 	if (netif_running(netdev)) {
 		atl1_down(adapter);
 		atl1_up(adapter);

drivers/net/ethernet/atheros/atlx/atl2.c

···
 	struct atl2_hw *hw = &adapter->hw;
 
 	/* set MTU */
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 	hw->max_frame_size = new_mtu;
 	ATL2_WRITE_REG(hw, REG_MTU, new_mtu + ETH_HLEN +
 		       VLAN_HLEN + ETH_FCS_LEN);

drivers/net/ethernet/broadcom/b44.c

···
 		/* We'll just catch it later when the
 		 * device is up'd.
 		 */
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 		return 0;
 	}
 
 	spin_lock_irq(&bp->lock);
 	b44_halt(bp);
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	b44_init_rings(bp);
 	b44_init_hw(bp, B44_FULL_RESET);
 	spin_unlock_irq(&bp->lock);

drivers/net/ethernet/broadcom/bcm63xx_enet.c

···
 	priv->rx_frag_size = SKB_DATA_ALIGN(priv->rx_buf_offset + priv->rx_buf_size) +
 					    SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/ethernet/broadcom/bnx2.c

···
 {
 	struct bnx2 *bp = netdev_priv(dev);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return bnx2_change_ring_size(bp, bp->rx_ring_size, bp->tx_ring_size,
 				     false);
 }

drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c

···
 	 * because the actual alloc size is
 	 * only updated as part of load
 	 */
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	if (!bnx2x_mtu_allows_gro(new_mtu))
 		dev->features &= ~NETIF_F_GRO_HW;

drivers/net/ethernet/broadcom/bnxt/bnxt.c

···
 	if (netif_running(dev))
 		bnxt_close_nic(bp, true, false);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	bnxt_set_ring_params(bp);
 
 	if (netif_running(dev))

drivers/net/ethernet/broadcom/tg3.c

···
 static inline void tg3_set_mtu(struct net_device *dev, struct tg3 *tp,
 			       int new_mtu)
 {
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	if (new_mtu > ETH_DATA_LEN) {
 		if (tg3_flag(tp, 5780_CLASS)) {

drivers/net/ethernet/brocade/bna/bnad.c

···
 	mutex_lock(&bnad->conf_mutex);
 
 	mtu = netdev->mtu;
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	frame = BNAD_FRAME_SIZE(mtu);
 	new_frame = BNAD_FRAME_SIZE(new_mtu);

drivers/net/ethernet/cadence/macb_main.c

···
 	if (netif_running(dev))
 		return -EBUSY;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	return 0;
 }

drivers/net/ethernet/calxeda/xgmac.c

···
 
 	/* Bring interface down, change mtu and bring interface back up */
 	xgmac_stop(dev);
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return xgmac_open(dev);
 }
 

drivers/net/ethernet/cavium/liquidio/lio_core.c

···
 		return -EINVAL;
 	}
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 	lio->mtu = new_mtu;
 
 	WRITE_ONCE(sc->caller_is_done, true);

drivers/net/ethernet/cavium/liquidio/lio_vf_rep.c

···
 		return -EIO;
 	}
 
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 
 	return 0;
 }

drivers/net/ethernet/cavium/octeon/octeon_mgmt.c

···
 	struct octeon_mgmt *p = netdev_priv(netdev);
 	int max_packet = new_mtu + ETH_HLEN + ETH_FCS_LEN;
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	/* HW lifts the limit if the frame is VLAN tagged
 	 * (+4 bytes per each tag, up to two tags)

drivers/net/ethernet/cavium/thunder/nicvf_main.c

···
 		return -EINVAL;
 	}
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (!netif_running(netdev))
 		return 0;

drivers/net/ethernet/chelsio/cxgb/cxgb2.c

···
 		return -EOPNOTSUPP;
 	if ((ret = mac->ops->set_mtu(mac, new_mtu)))
 		return ret;
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/ethernet/chelsio/cxgb3/cxgb3_main.c

···
 
 	if ((ret = t3_mac_set_mtu(&pi->mac, new_mtu)))
 		return ret;
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	init_port_mtus(adapter);
 	if (adapter->params.rev == 0 && offload_running(adapter))
 		t3_load_mtus(adapter, adapter->params.mtus,

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c

···
 	ret = t4_set_rxmode(pi->adapter, pi->adapter->mbox, pi->viid,
 			    pi->viid_mirror, new_mtu, -1, -1, -1, -1, true);
 	if (!ret)
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 	return ret;
 }
 

drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c

···
 	ret = t4vf_set_rxmode(pi->adapter, pi->viid, new_mtu,
 			      -1, -1, -1, -1, true);
 	if (!ret)
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 	return ret;
 }
 

drivers/net/ethernet/cisco/enic/enic_main.c

···
 			return err;
 	}
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (running) {
 		err = enic_open(netdev);

drivers/net/ethernet/cortina/gemini.c

···
 
 	gmac_disable_tx_rx(netdev);
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 	gmac_update_config0_reg(netdev, max_len << CONFIG0_MAXLEN_SHIFT,
 				CONFIG0_MAXLEN_MASK);
 

drivers/net/ethernet/dlink/sundance.c

···
 {
 	if (netif_running(dev))
 		return -EBUSY;
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/ethernet/faraday/ftmac100.c

···
 	}
 	iowrite32(maccr, priv->base + FTMAC100_OFFSET_MACCR);
 
-	netdev->mtu = mtu;
+	WRITE_ONCE(netdev->mtu, mtu);
 
 	return 0;
 }

drivers/net/ethernet/freescale/dpaa/dpaa_eth.c

···
 	if (priv->xdp_prog && !xdp_validate_mtu(priv, new_mtu))
 		return -EINVAL;
 
-	net_dev->mtu = new_mtu;
+	WRITE_ONCE(net_dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c

···
 		return err;
 
 out:
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c

···
 		return err;
 	}
 
-	netdev->mtu = mtu;
+	WRITE_ONCE(netdev->mtu, mtu);
 	return 0;
 }
 

drivers/net/ethernet/freescale/gianfar.c

···
 	if (dev->flags & IFF_UP)
 		stop_gfar(dev);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	if (dev->flags & IFF_UP)
 		startup_gfar(dev);

drivers/net/ethernet/fungible/funeth/funeth_main.c

···
 
 	rc = fun_port_write_cmd(fp, FUN_ADMIN_PORT_KEY_MTU, new_mtu);
 	if (!rc)
-		netdev->mtu = new_mtu;
+		WRITE_ONCE(netdev->mtu, new_mtu);
 	return rc;
 }
 

drivers/net/ethernet/hisilicon/hns/hns_enet.c

···
 	}
 
 	/* finally, set new mtu to netdevice */
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 
 out:
 	if (if_running) {

drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

···
 		netdev_err(netdev, "failed to change MTU in hardware %d\n",
 			   ret);
 	else
-		netdev->mtu = new_mtu;
+		WRITE_ONCE(netdev->mtu, new_mtu);
 
 	return ret;
 }

drivers/net/ethernet/huawei/hinic/hinic_main.c

···
 	if (err)
 		netif_err(nic_dev, drv, netdev, "Failed to set port mtu\n");
 	else
-		netdev->mtu = new_mtu;
+		WRITE_ONCE(netdev->mtu, new_mtu);
 
 	return err;
 }

drivers/net/ethernet/ibm/emac/core.c

···
 		/* This is to prevent starting RX channel in emac_rx_enable() */
 		set_bit(MAL_COMMAC_RX_STOPPED, &dev->commac.flags);
 
-		dev->ndev->mtu = new_mtu;
+		WRITE_ONCE(dev->ndev->mtu, new_mtu);
 		emac_full_tx_reset(dev);
 	}
 
···
 	}
 
 	if (!ret) {
-		ndev->mtu = new_mtu;
+		WRITE_ONCE(ndev->mtu, new_mtu);
 		dev->rx_skb_size = emac_rx_skb_size(new_mtu);
 		dev->rx_sync_size = emac_rx_sync_size(new_mtu);
 	}

drivers/net/ethernet/ibm/ibmveth.c

···
 		adapter->rx_buff_pool[i].active = 1;
 
 		if (new_mtu_oh <= adapter->rx_buff_pool[i].buff_size) {
-			dev->mtu = new_mtu;
+			WRITE_ONCE(dev->mtu, new_mtu);
 			vio_cmo_set_dev_desired(viodev,
 						ibmveth_get_desired_dma
 						(viodev));

drivers/net/ethernet/intel/e1000/e1000_main.c

···
 
 	netdev_dbg(netdev, "changing MTU from %d to %d\n",
 		   netdev->mtu, new_mtu);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (netif_running(netdev))
 		e1000_up(adapter);

drivers/net/ethernet/intel/e1000e/netdev.c

···
 	adapter->max_frame_size = max_frame;
 	netdev_dbg(netdev, "changing MTU from %d to %d\n",
 		   netdev->mtu, new_mtu);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	pm_runtime_get_sync(netdev->dev.parent);
 

drivers/net/ethernet/intel/i40e/i40e_main.c

···
 
 	netdev_dbg(netdev, "changing MTU from %d to %d\n",
 		   netdev->mtu, new_mtu);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 	if (netif_running(netdev))
 		i40e_vsi_reinit_locked(vsi);
 	set_bit(__I40E_CLIENT_SERVICE_REQUESTED, pf->state);

drivers/net/ethernet/intel/iavf/iavf_main.c

···
 
 	netdev_dbg(netdev, "changing MTU from %d to %d\n",
 		   netdev->mtu, new_mtu);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (netif_running(netdev)) {
 		iavf_schedule_reset(adapter, IAVF_FLAG_RESET_NEEDED);

drivers/net/ethernet/intel/ice/ice_main.c

···
 		return -EBUSY;
 	}
 
-	netdev->mtu = (unsigned int)new_mtu;
+	WRITE_ONCE(netdev->mtu, (unsigned int)new_mtu);
 	err = ice_down_up(vsi);
 	if (err)
 		return err;

drivers/net/ethernet/intel/idpf/idpf_lib.c

···
 	idpf_vport_ctrl_lock(netdev);
 	vport = idpf_netdev_to_vport(netdev);
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	err = idpf_initiate_soft_reset(vport, IDPF_SR_MTU_CHANGE);
 

drivers/net/ethernet/intel/igb/igb_main.c

···
 
 	netdev_dbg(netdev, "changing MTU from %d to %d\n",
 		   netdev->mtu, new_mtu);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (netif_running(netdev))
 		igb_up(adapter);

drivers/net/ethernet/intel/igbvf/netdev.c

···
 
 	netdev_dbg(netdev, "changing MTU from %d to %d\n",
 		   netdev->mtu, new_mtu);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (netif_running(netdev))
 		igbvf_up(adapter);

drivers/net/ethernet/intel/igc/igc_main.c

···
 		igc_down(adapter);
 
 	netdev_dbg(netdev, "changing MTU from %d to %d\n", netdev->mtu, new_mtu);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (netif_running(netdev))
 		igc_up(adapter);

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

···
 		   netdev->mtu, new_mtu);
 
 	/* must set new MTU before calling down or up */
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (netif_running(netdev))
 		ixgbe_reinit_locked(adapter);

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

···
 	       netdev->mtu, new_mtu);
 
 	/* must set new MTU before calling down or up */
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (netif_running(netdev))
 		ixgbevf_reinit_locked(adapter);

drivers/net/ethernet/jme.c

···
 {
 	struct jme_adapter *jme = netdev_priv(netdev);
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 	netdev_update_features(netdev);
 
 	jme_restart_rx_engine(jme);

drivers/net/ethernet/lantiq_etop.c

···
 	struct ltq_etop_priv *priv = netdev_priv(dev);
 	unsigned long flags;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	spin_lock_irqsave(&priv->lock, flags);
 	ltq_etop_w32((ETOP_PLEN_UNDER << 16) | new_mtu, LTQ_ETOP_IGPLEN);

drivers/net/ethernet/lantiq_xrx200.c

···
 	int curr_desc;
 	int ret = 0;
 
-	net_dev->mtu = new_mtu;
+	WRITE_ONCE(net_dev->mtu, new_mtu);
 	priv->rx_buf_size = xrx200_buffer_size(new_mtu);
 	priv->rx_skb_size = xrx200_skb_size(priv->rx_buf_size);
 
···
 		buff = ch_rx->rx_buff[ch_rx->dma.desc];
 		ret = xrx200_alloc_buf(ch_rx, netdev_alloc_frag);
 		if (ret) {
-			net_dev->mtu = old_mtu;
+			WRITE_ONCE(net_dev->mtu, old_mtu);
 			priv->rx_buf_size = xrx200_buffer_size(old_mtu);
 			priv->rx_skb_size = xrx200_skb_size(priv->rx_buf_size);
 			break;

drivers/net/ethernet/marvell/mv643xx_eth.c

···
 {
 	struct mv643xx_eth_private *mp = netdev_priv(dev);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	mv643xx_eth_recalc_skb_size(mp);
 	tx_set_rate(mp, 1000000000, 16777216);
 

drivers/net/ethernet/marvell/mvneta.c

···
 		return -EINVAL;
 	}
 
-	dev->mtu = mtu;
+	WRITE_ONCE(dev->mtu, mtu);
 
 	if (!netif_running(dev)) {
 		if (pp->bm_priv)

drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c

···
 	}
 
 out_set:
-	dev->mtu = mtu;
+	WRITE_ONCE(dev->mtu, mtu);
 	dev->wanted_features = dev->features;
 
 	netdev_update_features(dev);

drivers/net/ethernet/marvell/octeon_ep/octep_main.c

···
 				     true);
 	if (!err) {
 		oct->link_info.mtu = new_mtu;
-		netdev->mtu = new_mtu;
+		WRITE_ONCE(netdev->mtu, new_mtu);
 	}
 
 	return err;

drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_main.c

···
 	err = octep_vf_mbox_set_mtu(oct, new_mtu);
 	if (!err) {
 		oct->link_info.mtu = new_mtu;
-		netdev->mtu = new_mtu;
+		WRITE_ONCE(netdev->mtu, new_mtu);
 	}
 	return err;
 }

drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c

···
 
 	netdev_info(netdev, "Changing MTU from %d to %d\n",
 		    netdev->mtu, new_mtu);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (if_up)
 		err = otx2_open(netdev);

drivers/net/ethernet/marvell/octeontx2/nic/otx2_vf.c

···
 
 	netdev_info(netdev, "Changing MTU from %d to %d\n",
 		    netdev->mtu, new_mtu);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (if_up)
 		err = otx2vf_open(netdev);

drivers/net/ethernet/marvell/prestera/prestera_main.c

···
 	if (err)
 		return err;
 
-	dev->mtu = mtu;
+	WRITE_ONCE(dev->mtu, mtu);
 
 	return 0;
 }

drivers/net/ethernet/marvell/pxa168_eth.c

···
 {
 	struct pxa168_eth_private *pep = netdev_priv(dev);
 
-	dev->mtu = mtu;
+	WRITE_ONCE(dev->mtu, mtu);
 	set_port_config_ext(pep);
 
 	if (!netif_running(dev))

drivers/net/ethernet/marvell/skge.c

···
 	int err;
 
 	if (!netif_running(dev)) {
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 		return 0;
 	}
 
 	skge_down(dev);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	err = skge_up(dev);
 	if (err)

drivers/net/ethernet/marvell/sky2.c

···
 	u32 imask;
 
 	if (!netif_running(dev)) {
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 		netdev_update_features(dev);
 		return 0;
 	}
···
 	sky2_rx_stop(sky2);
 	sky2_rx_clean(sky2);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	netdev_update_features(dev);
 
 	mode = DATA_BLIND_VAL(DATA_BLIND_DEF) |	GM_SMOD_VLAN_ENA;

drivers/net/ethernet/mediatek/mtk_eth_soc.c

···
 	}
 
 	mtk_set_mcr_max_rx(mac, length);
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	return 0;
 }

drivers/net/ethernet/mellanox/mlx4/en_netdev.c

···
 	       sizeof(struct ethtool_flow_id) * MAX_NUM_OF_FS_RULES);
 
 	/* Calculate Rx buf size */
-	dev->mtu = min(dev->mtu, priv->max_mtu);
+	WRITE_ONCE(dev->mtu, min(dev->mtu, priv->max_mtu));
 	mlx4_en_calc_rx_buf(dev);
 	en_dbg(DRV, priv, "Rx buf size:%d\n", priv->rx_skb_size);
 
···
 	    !mlx4_en_check_xdp_mtu(dev, new_mtu))
 		return -EOPNOTSUPP;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	if (netif_running(dev)) {
 		mutex_lock(&mdev->state_lock);

drivers/net/ethernet/mellanox/mlx5/core/en_main.c

···
 	err = mlx5e_safe_switch_params(priv, &new_params, preactivate, NULL, reset);
 
 out:
-	netdev->mtu = params->sw_mtu;
+	WRITE_ONCE(netdev->mtu, params->sw_mtu);
 	mutex_unlock(&priv->state_lock);
 	return err;
 }

drivers/net/ethernet/mellanox/mlx5/core/ipoib/ipoib.c

···
 	if (err)
 		goto out;
 
-	netdev->mtu = new_params.sw_mtu;
+	WRITE_ONCE(netdev->mtu, new_params.sw_mtu);
 
 out:
 	mutex_unlock(&priv->state_lock);

drivers/net/ethernet/mellanox/mlx5/core/ipoib/ipoib_vlan.c

···
 	struct mlx5e_priv *priv = mlx5i_epriv(netdev);
 
 	mutex_lock(&priv->state_lock);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 	mutex_unlock(&priv->state_lock);
 
 	return 0;

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

···
 	err = mlxsw_sp_port_mtu_set(mlxsw_sp_port, mtu);
 	if (err)
 		goto err_port_mtu_set;
-	dev->mtu = mtu;
+	WRITE_ONCE(dev->mtu, mtu);
 	return 0;
 
 err_port_mtu_set:

drivers/net/ethernet/micrel/ksz884x.c

···
 	}
 	hw_mtu = (hw_mtu + 3) & ~3;
 	hw_priv->mtu = hw_mtu;
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	return 0;
 }

drivers/net/ethernet/microchip/lan743x_main.c

···
 
 	ret = lan743x_mac_set_mtu(adapter, new_mtu);
 	if (!ret)
-		netdev->mtu = new_mtu;
+		WRITE_ONCE(netdev->mtu, new_mtu);
 	return ret;
 }
 

drivers/net/ethernet/microchip/lan966x/lan966x_main.c

···
 
 	lan_wr(DEV_MAC_MAXLEN_CFG_MAX_LEN_SET(LAN966X_HW_MTU(new_mtu)),
 	       lan966x, DEV_MAC_MAXLEN_CFG(port->chip_port));
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	if (!lan966x->fdma)
 		return 0;

drivers/net/ethernet/microsoft/mana/mana_en.c

···
 		goto out;
 	}
 
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 
 	err = mana_attach(ndev);
 	if (err) {
 		netdev_err(ndev, "mana_attach failed: %d\n", err);
-		ndev->mtu = old_mtu;
+		WRITE_ONCE(ndev->mtu, old_mtu);
 	}
 
 out:

drivers/net/ethernet/myricom/myri10ge/myri10ge.c

···
 		/* if we change the mtu on an active device, we must
 		 * reset the device so the firmware sees the change */
 		myri10ge_close(dev);
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 		myri10ge_open(dev);
-	} else
-		dev->mtu = new_mtu;
-
+	} else {
+		WRITE_ONCE(dev->mtu, new_mtu);
+	}
 	return 0;
 }
 

drivers/net/ethernet/natsemi/natsemi.c

···
 
 static int natsemi_change_mtu(struct net_device *dev, int new_mtu)
 {
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	/* synchronized against open : rtnl_lock() held by caller */
 	if (netif_running(dev)) {

drivers/net/ethernet/neterion/s2io.c

···
 	struct s2io_nic *sp = netdev_priv(dev);
 	int ret = 0;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	if (netif_running(dev)) {
 		s2io_stop_all_tx_queue(sp);
 		s2io_card_down(sp);

drivers/net/ethernet/netronome/nfp/nfp_net_common.c

···
 	*dp = nn->dp;
 	nn->dp = new_dp;
 
-	nn->dp.netdev->mtu = new_dp.mtu;
+	WRITE_ONCE(nn->dp.netdev->mtu, new_dp.mtu);
 
 	if (!netif_is_rxfh_configured(nn->dp.netdev))
 		nfp_net_rss_init_itbl(nn);

drivers/net/ethernet/netronome/nfp/nfp_net_repr.c

···
 	if (err)
 		return err;
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	return 0;
 }

drivers/net/ethernet/ni/nixge.c

···
 	     NIXGE_MAX_JUMBO_FRAME_SIZE)
 		return -EINVAL;
 
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 
 	return 0;
 }

drivers/net/ethernet/nvidia/forcedeth.c

···
 	int old_mtu;
 
 	old_mtu = dev->mtu;
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	/* return early if the buffer sizes will not change */
 	if (old_mtu <= ETH_DATA_LEN && new_mtu <= ETH_DATA_LEN)

drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c

···
 		}
 	} else {
 		pch_gbe_reset(adapter);
-		netdev->mtu = new_mtu;
+		WRITE_ONCE(netdev->mtu, new_mtu);
 		adapter->hw.mac.max_frame_size = max_frame;
 	}
 

drivers/net/ethernet/pasemi/pasemi_mac.c

···
 	reg |= PAS_MAC_CFG_MACCFG_MAXF(new_mtu + ETH_HLEN + 4);
 	write_mac_reg(mac, PAS_MAC_CFG_MACCFG, reg);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	/* MTU + ETH_HLEN + VLAN_HLEN + 2 64B cachelines */
 	mac->bufsz = new_mtu + ETH_HLEN + ETH_FCS_LEN + LOCAL_SKB_ALIGN + 128;
 

drivers/net/ethernet/pensando/ionic/ionic_lif.c

···
 
 	/* if we're not running, nothing more to do */
 	if (!netif_running(netdev)) {
-		netdev->mtu = new_mtu;
+		WRITE_ONCE(netdev->mtu, new_mtu);
 		return 0;
 	}
 
 	mutex_lock(&lif->queue_lock);
 	ionic_stop_queues_reconfig(lif);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 	err = ionic_start_queues_reconfig(lif);
 	mutex_unlock(&lif->queue_lock);
 

drivers/net/ethernet/qlogic/netxen/netxen_nic_hw.c

···
 		rc = adapter->set_mtu(adapter, mtu);
 
 	if (!rc)
-		netdev->mtu = mtu;
+		WRITE_ONCE(netdev->mtu, mtu);
 
 	return rc;
 }

drivers/net/ethernet/qlogic/qede/qede_ethtool.c

···
 static void qede_update_mtu(struct qede_dev *edev,
 			    struct qede_reload_args *args)
 {
-	edev->ndev->mtu = args->u.mtu;
+	WRITE_ONCE(edev->ndev->mtu, args->u.mtu);
 }
 
 /* Netdevice NDOs */

drivers/net/ethernet/qlogic/qlcnic/qlcnic_hw.c

···
 	rc = qlcnic_fw_cmd_set_mtu(adapter, mtu);
 
 	if (!rc)
-		netdev->mtu = mtu;
+		WRITE_ONCE(netdev->mtu, mtu);
 
 	return rc;
 }

drivers/net/ethernet/qualcomm/emac/emac.c

···
 	netif_dbg(adpt, hw, adpt->netdev,
 		  "changing MTU from %d to %d\n", netdev->mtu,
 		  new_mtu);
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (netif_running(netdev))
 		return emac_reinit_locked(adpt);

drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c

···
 	    new_mtu > (priv->real_dev->mtu - headroom))
 		return -EINVAL;
 
-	rmnet_dev->mtu = new_mtu;
+	WRITE_ONCE(rmnet_dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/ethernet/realtek/8139cp.c

···
 
 	/* if network interface not up, no need for complexity */
 	if (!netif_running(dev)) {
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 		cp_set_rxbufsize(cp);	/* set new rx buf size */
 		return 0;
 	}
 
 	/* network IS up, close it, reset MTU, and come up again. */
 	cp_close(dev);
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	cp_set_rxbufsize(cp);
 	return cp_open(dev);
 }

drivers/net/ethernet/realtek/r8169_main.c

···
 {
 	struct rtl8169_private *tp = netdev_priv(dev);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	netdev_update_features(dev);
 	rtl_jumbo_config(tp);
 	rtl_set_eee_txidle_timer(tp);

drivers/net/ethernet/renesas/ravb_main.c

···
 {
 	struct ravb_private *priv = netdev_priv(ndev);
 
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 
 	if (netif_running(ndev)) {
 		synchronize_irq(priv->emac_irq);

drivers/net/ethernet/renesas/sh_eth.c

···
 	if (netif_running(ndev))
 		return -EBUSY;
 
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 	netdev_update_features(ndev);
 
 	return 0;

drivers/net/ethernet/rocker/rocker_main.c

···
 		rocker_port_stop(dev);
 
 	netdev_info(dev, "MTU change from %d to %d\n", dev->mtu, new_mtu);
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	err = rocker_cmd_set_port_settings_mtu(rocker_port, new_mtu);
 	if (err)

drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c

···
  */
 static int sxgbe_change_mtu(struct net_device *dev, int new_mtu)
 {
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	if (!netif_running(dev))
 		return 0;

drivers/net/ethernet/sfc/efx_common.c

···
 	efx_stop_all(efx);
 
 	mutex_lock(&efx->mac_lock);
-	net_dev->mtu = new_mtu;
+	WRITE_ONCE(net_dev->mtu, new_mtu);
 	efx_mac_reconfigure(efx, true);
 	mutex_unlock(&efx->mac_lock);
 

drivers/net/ethernet/sfc/falcon/efx.c

···
 	ef4_stop_all(efx);
 
 	mutex_lock(&efx->mac_lock);
-	net_dev->mtu = new_mtu;
+	WRITE_ONCE(net_dev->mtu, new_mtu);
 	ef4_mac_reconfigure(efx);
 	mutex_unlock(&efx->mac_lock);
 

drivers/net/ethernet/sfc/siena/efx_common.c

···
 	efx_siena_stop_all(efx);
 
 	mutex_lock(&efx->mac_lock);
-	net_dev->mtu = new_mtu;
+	WRITE_ONCE(net_dev->mtu, new_mtu);
 	efx_siena_mac_reconfigure(efx, true);
 	mutex_unlock(&efx->mac_lock);
 

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

···
 		stmmac_set_rx_mode(dev);
 	}
 
-	dev->mtu = mtu;
+	WRITE_ONCE(dev->mtu, mtu);
 	netdev_update_features(dev);
 
 	return 0;

drivers/net/ethernet/sun/cassini.c

···
 {
 	struct cas *cp = netdev_priv(dev);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	if (!netif_running(dev) || !netif_device_present(dev))
 		return 0;
 

drivers/net/ethernet/sun/niu.c

···
 	orig_jumbo = (dev->mtu > ETH_DATA_LEN);
 	new_jumbo = (new_mtu > ETH_DATA_LEN);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	if (!netif_running(dev) ||
 	    (orig_jumbo == new_jumbo))

drivers/net/ethernet/sun/sungem.c

···
 {
 	struct gem *gp = netdev_priv(dev);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	/* We'll just catch it later when the device is up'd or resumed */
 	if (!netif_running(dev) || !netif_device_present(dev))

drivers/net/ethernet/synopsys/dwc-xlgmac-net.c

···
 		return ret;
 
 	pdata->rx_buf_size = ret;
-	netdev->mtu = mtu;
+	WRITE_ONCE(netdev->mtu, mtu);
 
 	xlgmac_restart_dev(pdata);
 

drivers/net/ethernet/tehuti/tehuti.c

···
 {
 	ENTER;
 
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 	if (netif_running(ndev)) {
 		bdx_close(ndev);
 		bdx_open(ndev);

drivers/net/ethernet/via/via-velocity.c

···
 	int ret = 0;
 
 	if (!netif_running(dev)) {
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 		goto out_0;
 	}
 
···
 		tmp_vptr->rx = rx;
 		tmp_vptr->tx = tx;
 
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 
 		velocity_init_registers(vptr, VELOCITY_INIT_COLD);
 

drivers/net/ethernet/wangxun/libwx/wx_hw.c

···
 {
 	struct wx *wx = netdev_priv(netdev);
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 	wx_set_rx_buffer_len(wx);
 
 	return 0;

drivers/net/ethernet/xilinx/xilinx_axienet_main.c

···
 		XAE_TRL_SIZE) > lp->rxmem)
 		return -EINVAL;
 
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 
 	return 0;
 }

drivers/net/ethernet/xscale/ixp4xx_eth.c

···
 			return ret;
 	}
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	return 0;
 }

drivers/net/fjes/fjes_main.c

···
 		netif_tx_stop_all_queues(netdev);
 	}
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	if (running) {
 		for (epidx = 0; epidx < hw->max_epid; epidx++) {

drivers/net/geneve.c

···
 	else if (new_mtu < dev->min_mtu)
 		new_mtu = dev->min_mtu;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/hyperv/netvsc_drv.c

···
 	if (ret)
 		goto rollback_vf;
 
-	ndev->mtu = mtu;
+	WRITE_ONCE(ndev->mtu, mtu);
 
 	ret = netvsc_attach(ndev, device_info);
 	if (!ret)
 		goto out;
 
 	/* Attempt rollback to original MTU */
-	ndev->mtu = orig_mtu;
+	WRITE_ONCE(ndev->mtu, orig_mtu);
 
 	if (netvsc_attach(ndev, device_info))
 		netdev_err(ndev, "restoring mtu failed\n");

drivers/net/macsec.c

···
 	if (macsec->real_dev->mtu - extra < new_mtu)
 		return -ERANGE;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	return 0;
 }

drivers/net/macvlan.c

···
 
 	if (vlan->lowerdev->mtu < new_mtu)
 		return -EINVAL;
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/net_failover.c

···
 		}
 	}
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	return 0;
 }

drivers/net/netdevsim/netdev.c

···
 	if (ns->xdp.prog && new_mtu > NSIM_XDP_MAX_MTU)
 		return -EBUSY;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	return 0;
 }

drivers/net/ntb_netdev.c

···
 		return -EINVAL;
 
 	if (!netif_running(ndev)) {
-		ndev->mtu = new_mtu;
+		WRITE_ONCE(ndev->mtu, new_mtu);
 		return 0;
 	}
 
···
 		}
 	}
 
-	ndev->mtu = new_mtu;
+	WRITE_ONCE(ndev->mtu, new_mtu);
 
 	ntb_transport_link_up(dev->qp);
 

drivers/net/slip/slip.c

···
 		}
 	}
 	sl->mtu      = mtu;
-	dev->mtu      = mtu;
+	WRITE_ONCE(dev->mtu, mtu);
 	sl->buffsize = len;
 	err = 0;
 

drivers/net/team/team_core.c

···
 	team->port_mtu_change_allowed = false;
 	mutex_unlock(&team->lock);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	return 0;
 

drivers/net/usb/aqc111.c

···
 	u16 reg16 = 0;
 	u8 buf[5];
 
-	net->mtu = new_mtu;
+	WRITE_ONCE(net->mtu, new_mtu);
 	dev->hard_mtu = net->mtu + net->hard_header_len;
 
 	aqc111_read16_cmd(dev, AQ_ACCESS_MAC, SFR_MEDIUM_STATUS_MODE,

drivers/net/usb/asix_devices.c

···
 	if ((ll_mtu % dev->maxpacket) == 0)
 		return -EDOM;
 
-	net->mtu = new_mtu;
+	WRITE_ONCE(net->mtu, new_mtu);
 	dev->hard_mtu = net->mtu + net->hard_header_len;
 	ax88178_set_mfb(dev);
 

drivers/net/usb/ax88179_178a.c

···
 	struct usbnet *dev = netdev_priv(net);
 	u16 tmp16;
 
-	net->mtu = new_mtu;
+	WRITE_ONCE(net->mtu, new_mtu);
 	dev->hard_mtu = net->mtu + net->hard_header_len;
 
 	if (net->mtu > 1500) {

drivers/net/usb/cdc_ncm.c

···
 {
 	struct usbnet *dev = netdev_priv(net);
 
-	net->mtu = new_mtu;
+	WRITE_ONCE(net->mtu, new_mtu);
 	cdc_ncm_set_dgram_size(dev, new_mtu + cdc_ncm_eth_hlen(dev));
 
 	return 0;

drivers/net/usb/lan78xx.c

···
 
 	ret = lan78xx_set_rx_max_frame_length(dev, max_frame_len);
 	if (!ret)
-		netdev->mtu = new_mtu;
+		WRITE_ONCE(netdev->mtu, new_mtu);
 
 	usb_autopm_put_interface(dev->intf);
 

drivers/net/usb/r8152.c

···
 	case RTL_VER_01:
 	case RTL_VER_02:
 	case RTL_VER_07:
-		dev->mtu = new_mtu;
+		WRITE_ONCE(dev->mtu, new_mtu);
 		return 0;
 	default:
 		break;
···
 
 	mutex_lock(&tp->control);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	if (netif_running(dev)) {
 		if (tp->rtl_ops.change_mtu)

drivers/net/usb/usbnet.c

···
 	// no second zero-length packet read wanted after mtu-sized packets
 	if ((ll_mtu % dev->maxpacket) == 0)
 		return -EDOM;
-	net->mtu = new_mtu;
+	WRITE_ONCE(net->mtu, new_mtu);
 
 	dev->hard_mtu = net->mtu + net->hard_header_len;
 	if (dev->rx_urb_size == old_hard_mtu) {

drivers/net/vmxnet3/vmxnet3_drv.c

···
 	struct vmxnet3_adapter *adapter = netdev_priv(netdev);
 	int err = 0;
 
-	netdev->mtu = new_mtu;
+	WRITE_ONCE(netdev->mtu, new_mtu);
 
 	/*
 	 * Reset_work may be in the middle of resetting the device, wait for its

drivers/net/vsockmon.c

···
 	if (!vsockmon_is_valid_mtu(new_mtu))
 		return -EINVAL;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/vxlan/vxlan_core.c

···
 			return -EINVAL;
 	}
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 

drivers/net/xen-netback/interface.c

···
 
 	if (mtu > max)
 		return -EINVAL;
-	dev->mtu = mtu;
+	WRITE_ONCE(dev->mtu, mtu);
 	return 0;
 }
 

drivers/net/xen-netfront.c

···
 
 	if (mtu > max)
 		return -EINVAL;
-	dev->mtu = mtu;
+	WRITE_ONCE(dev->mtu, mtu);
 	return 0;
 }
 

drivers/s390/net/ctcm_main.c

···
 			return -EINVAL;
 		dev->hard_header_len = LL_HEADER_LENGTH + 2;
 	}
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 

net/8021q/vlan_dev.c

···
 	if (max_mtu < new_mtu)
 		return -ERANGE;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	return 0;
 }

net/batman-adv/soft-interface.c

···
 	if (new_mtu < ETH_MIN_MTU || new_mtu > batadv_hardif_min_mtu(dev))
 		return -EINVAL;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	bat_priv->mtu_set_by_user = new_mtu;
 
 	return 0;

net/bridge/br_device.c

···
 {
 	struct net_bridge *br = netdev_priv(dev);
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	/* this flag will be cleared if the MTU was automatically adjusted */
 	br_opt_toggle(br, BROPT_MTU_SET_BY_USER, true);

net/dsa/user.c

···
 	if (err)
 		goto out_port_failed;
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	dsa_bridge_mtu_normalization(dp);
 

net/hsr/hsr_device.c

···
 		return -EINVAL;
 	}
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 
 	return 0;
 }

net/hsr/hsr_main.c

···
 			break; /* Handled in ndo_change_mtu() */
 		mtu_max = hsr_get_max_mtu(port->hsr);
 		master = hsr_port_get_hsr(port->hsr, HSR_PT_MASTER);
-		master->dev->mtu = mtu_max;
+		WRITE_ONCE(master->dev->mtu, mtu_max);
 		break;
 	case NETDEV_UNREGISTER:
 		if (!is_hsr_master(dev)) {

net/ipv4/ip_gre.c

···
 		dev->needed_headroom += len;
 
 	if (set_mtu)
-		dev->mtu = max_t(int, dev->mtu - len, 68);
+		WRITE_ONCE(dev->mtu, max_t(int, dev->mtu - len, 68));
 
 	if (test_bit(IP_TUNNEL_SEQ_BIT, tunnel->parms.o_flags) ||
 	    (test_bit(IP_TUNNEL_CSUM_BIT, tunnel->parms.o_flags) &&

net/ipv4/ip_tunnel.c

···
 		t->fwmark = fwmark;
 		mtu = ip_tunnel_bind_dev(dev);
 		if (set_mtu)
-			dev->mtu = mtu;
+			WRITE_ONCE(dev->mtu, mtu);
 	}
 	dst_cache_reset(&t->dst_cache);
 	netdev_state_change(dev);
···
 		new_mtu = max_mtu;
 	}
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(__ip_tunnel_change_mtu);

net/ipv6/ip6_tunnel.c

···
 		if (new_mtu > IP_MAX_MTU - dev->hard_header_len)
 			return -EINVAL;
 	}
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }
 EXPORT_SYMBOL(ip6_tnl_change_mtu);

net/ipv6/ip6_vti.c

···
 		dev->flags &= ~IFF_POINTOPOINT;
 
 	if (keep_mtu && dev->mtu) {
-		dev->mtu = clamp(dev->mtu, dev->min_mtu, dev->max_mtu);
+		WRITE_ONCE(dev->mtu,
+			   clamp(dev->mtu, dev->min_mtu, dev->max_mtu));
 		return;
 	}
 

net/sched/sch_teql.c

···
 		} while ((q = NEXT_SLAVE(q)) != m->slaves);
 	}
 
-	dev->mtu = new_mtu;
+	WRITE_ONCE(dev->mtu, new_mtu);
 	return 0;
 }