[PATCH v3] ravb: implement MTU change while device is up

[Ulrich Hecht <uli+renesas@fpond.eu>]

Uses the same method as various other drivers: shut the device down,
change the MTU, then bring it back up again.

Tested on Renesas D3 Draak and M3-W Salvator-X boards.

Signed-off-by: Ulrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
---

Hi!

This revision reverts the MTU change if re-opening the device fails.

CU
Uli


 drivers/net/ethernet/renesas/ravb_main.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index ef8f089..402bcec 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1810,12 +1810,24 @@ static int ravb_do_ioctl(struct net_device *ndev, struct ifreq *req, int cmd)
 
 static int ravb_change_mtu(struct net_device *ndev, int new_mtu)
 {
+	unsigned int old_mtu = ndev->mtu;
+
 	if (netif_running(ndev))
-		return -EBUSY;
+		ravb_close(ndev);
 
 	ndev->mtu = new_mtu;
 	netdev_update_features(ndev);
 
+	if (netif_running(ndev)) {
+		int err = ravb_open(ndev);
+
+		if (err) {
+			ndev->mtu = old_mtu;
+			netdev_update_features(ndev);
+			return err;
+		}
+	}
+
 	return 0;
 }
 
-- 
2.7.4