pch_gbe: Validate hwtstamp_config completely before applying it

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/oki-semi/pch_gbe/pch_gbe_main.c

@@ -245,16 +245,8 @@ static int hwtstamp_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
 	/* Get ieee1588's dev information */
 	pdev = adapter->ptp_pdev;
 
-	switch (cfg.tx_type) {
-	case HWTSTAMP_TX_OFF:
-		adapter->hwts_tx_en = 0;
-		break;
-	case HWTSTAMP_TX_ON:
-		adapter->hwts_tx_en = 1;
-		break;
-	default:
+	if (cfg.tx_type != HWTSTAMP_TX_OFF && cfg.tx_type != HWTSTAMP_TX_ON)
 		return -ERANGE;
-	}
 
 	switch (cfg.rx_filter) {
 	case HWTSTAMP_FILTER_NONE:
@@ -284,6 +276,8 @@ static int hwtstamp_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
 		return -ERANGE;
 	}
 
+	adapter->hwts_tx_en = cfg.tx_type == HWTSTAMP_TX_ON;
+
 	/* Clear out any old time stamps. */
 	pch_ch_event_write(pdev, TX_SNAPSHOT_LOCKED | RX_SNAPSHOT_LOCKED);