[PATCH 4.19 20/45] mvpp2: refactor MTU change code

From: Greg Kroah-Hartman
Date: Thu Aug 08 2019 - 15:10:14 EST


From: Matteo Croce <mcroce@xxxxxxxxxx>

[ 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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 41 +++++++-----------------
1 file changed, 13 insertions(+), 28 deletions(-)

--- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
+++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c
@@ -3501,6 +3501,7 @@ static int mvpp2_set_mac_address(struct
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)) {
@@ -3509,40 +3510,24 @@ static int mvpp2_change_mtu(struct net_d
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;
- }
+ if (running)
+ mvpp2_stop_dev(port);

+ err = mvpp2_bm_update_mtu(dev, mtu);
+ if (err) {
+ netdev_err(dev, "failed to change MTU\n");
/* Reconfigure BM to the original MTU */
- err = mvpp2_bm_update_mtu(dev, dev->mtu);
- if (err)
- goto log_error;
+ mvpp2_bm_update_mtu(dev, dev->mtu);
+ } else {
+ port->pkt_size = MVPP2_RX_PKT_SIZE(mtu);
}

- mvpp2_stop_dev(port);
-
- err = mvpp2_bm_update_mtu(dev, mtu);
- if (!err) {
- port->pkt_size = MVPP2_RX_PKT_SIZE(mtu);
- goto out_start;
+ if (running) {
+ mvpp2_start_dev(port);
+ mvpp2_egress_enable(port);
+ mvpp2_ingress_enable(port);
}

- /* 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);
-
- return 0;
-log_error:
- netdev_err(dev, "failed to change MTU\n");
return err;
}