mvpp2: refactor MTU change code

BugLink: https://bugs.launchpad.net/bugs/1840378
[ Upstream commit 230bd958c2c846ee292aa38bc6b006296c24ca01 ]

The MTU change code can call napi_disable() with the device already down,
leading to a deadlock. Also, lot of code is duplicated unnecessarily.

Rework mvpp2_change_mtu() to avoid the deadlock and remove duplicated code.

Fixes: 3f518509dedc ("ethernet: Add new driver for Marvell Armada 375 network unit")
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/net/ethernet/marvell/mvpp2.c b/drivers/net/ethernet/marvell/mvpp2.c
index 9333681380cdabee7fe912108a5ecdef71468f5c..0a611f65ee9752706a2835d2da85879b80f639aa 100644 (file)
--- a/drivers/net/ethernet/marvell/mvpp2.c
+++ b/drivers/net/ethernet/marvell/mvpp2.c
@@ -7196,6 +7196,7 @@ log_error:
 static int mvpp2_change_mtu(struct net_device *dev, int mtu)
 {
        struct mvpp2_port *port = netdev_priv(dev);
+       bool running = netif_running(dev);
        int err;
 
        if (!IS_ALIGNED(MVPP2_RX_PKT_SIZE(mtu), 8)) {
@@ -7204,40 +7205,24 @@ static int mvpp2_change_mtu(struct net_device *dev, int mtu)
                mtu = ALIGN(MVPP2_RX_PKT_SIZE(mtu), 8);
        }
 
-       if (!netif_running(dev)) {
-               err = mvpp2_bm_update_mtu(dev, mtu);
-               if (!err) {
-                       port->pkt_size =  MVPP2_RX_PKT_SIZE(mtu);
-                       return 0;
-               }
-
-               /* Reconfigure BM to the original MTU */
-               err = mvpp2_bm_update_mtu(dev, dev->mtu);
-               if (err)
-                       goto log_error;
-       }
-
-       mvpp2_stop_dev(port);
+       if (running)
+               mvpp2_stop_dev(port);
 
        err = mvpp2_bm_update_mtu(dev, mtu);
-       if (!err) {
+       if (err) {
+               netdev_err(dev, "failed to change MTU\n");
+               /* Reconfigure BM to the original MTU */
+               mvpp2_bm_update_mtu(dev, dev->mtu);
+       } else {
                port->pkt_size =  MVPP2_RX_PKT_SIZE(mtu);
-               goto out_start;
        }
 
-       /* Reconfigure BM to the original MTU */
-       err = mvpp2_bm_update_mtu(dev, dev->mtu);
-       if (err)
-               goto log_error;
-
-out_start:
-       mvpp2_start_dev(port);
-       mvpp2_egress_enable(port);
-       mvpp2_ingress_enable(port);
+       if (running) {
+               mvpp2_start_dev(port);
+               mvpp2_egress_enable(port);
+               mvpp2_ingress_enable(port);
+       }
 
-       return 0;
-log_error:
-       netdev_err(dev, "failed to change MTU\n");
        return err;
 }