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

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Date:   Wed,  8 May 2019 17:21:22 +0200
From:   Ulrich Hecht <uli+renesas@...nd.eu>
To:     linux-renesas-soc@...r.kernel.org
Cc:     netdev@...r.kernel.org, davem@...emloft.net, wsa@...-dreams.de,
        horms@...ge.net.au, magnus.damm@...il.com,
        Ulrich Hecht <uli+renesas@...nd.eu>
Subject: [PATCH] ravb: implement MTU change while device is up

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 board.

Signed-off-by: Ulrich Hecht <uli+renesas@...nd.eu>
---
 drivers/net/ethernet/renesas/ravb_main.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index ef8f089..02c247c 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1810,13 +1810,16 @@ 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)
 {
-	if (netif_running(ndev))
-		return -EBUSY;
+	if (!netif_running(ndev)) {
+		ndev->mtu = new_mtu;
+		netdev_update_features(ndev);
+		return 0;
+	}
 
+	ravb_close(ndev);
 	ndev->mtu = new_mtu;
-	netdev_update_features(ndev);
 
-	return 0;
+	return ravb_open(ndev);
 }
 
 static void ravb_set_rx_csum(struct net_device *ndev, bool enable)
-- 
2.7.4