[PATCHv2 net-next 1/4] nfp: return error if MTU change fails

When reopening device fails after MTU change, let the userspace
know.  MTU remains changed even though error is returned, this
is what all ethernet devices are doing.

Signed-off-by: Jakub Kicinski <redacted>
Reviewed-by: Rolf Neugebauer <redacted>
---
Dave,

I know this is not what you asked for but, since we are using FW
commands to disable/enable RX, even if we allocate all required
resources before freeing old ones we still cannot guarantee that
the reenabling operation will not fail.  Should we refuse to do
MTU changes while the interface is running altogether?

---
 drivers/net/ethernet/netronome/nfp/nfp_net_common.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
index 43c618bafdb6..006d9600240f 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_common.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_common.c

@@ -1911,6 +1911,7 @@ static void nfp_net_set_rx_mode(struct net_device *netdev)
 static int nfp_net_change_mtu(struct net_device *netdev, int new_mtu)
 {
 	struct nfp_net *nn = netdev_priv(netdev);
+	int ret = 0;
 	u32 tmp;
 
 	nn_dbg(nn, "New MTU = %d\n", new_mtu);

@@ -1929,10 +1930,10 @@ static int nfp_net_change_mtu(struct net_device *netdev, int new_mtu)
 	/* restart if running */
 	if (netif_running(netdev)) {
 		nfp_net_netdev_close(netdev);
-		nfp_net_netdev_open(netdev);
+		ret = nfp_net_netdev_open(netdev);
 	}
 
-	return 0;
+	return ret;
 }
 
 static struct rtnl_link_stats64 *nfp_net_stat64(struct net_device *netdev,

-- 
1.9.1