stmmac: Validate hwtstamp_config completely before applying it

stmmac_hwtstamp_ioctl() should validate all fields of hwtstamp_config
before making any changes.  Currently it sets the TX configuration
before validating the rx_filter field.

Compile-tested only.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -435,16 +435,9 @@ static int stmmac_hwtstamp_ioctl(struct net_device *dev, struct ifreq *ifr)
 	if (config.flags)
 		return -EINVAL;
 
-	switch (config.tx_type) {
-	case HWTSTAMP_TX_OFF:
-		priv->hwts_tx_en = 0;
-		break;
-	case HWTSTAMP_TX_ON:
-		priv->hwts_tx_en = 1;
-		break;
-	default:
+	if (config.tx_type != HWTSTAMP_TX_OFF &&
+	    config.tx_type != HWTSTAMP_TX_ON)
 		return -ERANGE;
-	}
 
 	if (priv->adv_ts) {
 		switch (config.rx_filter) {
@@ -576,6 +569,7 @@ static int stmmac_hwtstamp_ioctl(struct net_device *dev, struct ifreq *ifr)
 		}
 	}
 	priv->hwts_rx_en = ((config.rx_filter == HWTSTAMP_FILTER_NONE) ? 0 : 1);
+	priv->hwts_tx_en = config.tx_type == HWTSTAMP_TX_ON;
 
 	if (!priv->hwts_tx_en && !priv->hwts_rx_en)
 		priv->hw->ptp->config_hw_tstamping(priv->ioaddr, 0);