[PATCH net-next 11/12] net: dpaa2-switch: serialize changes to priv->mac with a mutex
From: Vladimir Oltean
Date: Tue Nov 29 2022 - 09:14:50 EST
The dpaa2-switch driver uses a DPMAC in the same way as the dpaa2-eth
driver, so we need to duplicate the locking solution established by the
previous change to the switch driver as well.
Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
---
.../freescale/dpaa2/dpaa2-switch-ethtool.c | 32 +++++++++++++++----
.../ethernet/freescale/dpaa2/dpaa2-switch.c | 31 ++++++++++++++++--
.../ethernet/freescale/dpaa2/dpaa2-switch.h | 2 ++
3 files changed, 55 insertions(+), 10 deletions(-)
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch-ethtool.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch-ethtool.c
index 76a4b09e2854..6bc1988be311 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch-ethtool.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch-ethtool.c
@@ -60,11 +60,18 @@ dpaa2_switch_get_link_ksettings(struct net_device *netdev,
{
struct ethsw_port_priv *port_priv = netdev_priv(netdev);
struct dpsw_link_state state = {0};
- int err = 0;
+ int err;
+
+ mutex_lock(&port_priv->mac_lock);
- if (dpaa2_switch_port_is_type_phy(port_priv))
- return phylink_ethtool_ksettings_get(port_priv->mac->phylink,
- link_ksettings);
+ if (dpaa2_switch_port_is_type_phy(port_priv)) {
+ err = phylink_ethtool_ksettings_get(port_priv->mac->phylink,
+ link_ksettings);
+ mutex_unlock(&port_priv->mac_lock);
+ return err;
+ }
+
+ mutex_unlock(&port_priv->mac_lock);
err = dpsw_if_get_link_state(port_priv->ethsw_data->mc_io, 0,
port_priv->ethsw_data->dpsw_handle,
@@ -99,9 +106,16 @@ dpaa2_switch_set_link_ksettings(struct net_device *netdev,
bool if_running;
int err = 0, ret;
- if (dpaa2_switch_port_is_type_phy(port_priv))
- return phylink_ethtool_ksettings_set(port_priv->mac->phylink,
- link_ksettings);
+ mutex_lock(&port_priv->mac_lock);
+
+ if (dpaa2_switch_port_is_type_phy(port_priv)) {
+ err = phylink_ethtool_ksettings_set(port_priv->mac->phylink,
+ link_ksettings);
+ mutex_unlock(&port_priv->mac_lock);
+ return err;
+ }
+
+ mutex_unlock(&port_priv->mac_lock);
/* Interface needs to be down to change link settings */
if_running = netif_running(netdev);
@@ -189,8 +203,12 @@ static void dpaa2_switch_ethtool_get_stats(struct net_device *netdev,
dpaa2_switch_ethtool_counters[i].name, err);
}
+ mutex_lock(&port_priv->mac_lock);
+
if (dpaa2_switch_port_has_mac(port_priv))
dpaa2_mac_get_ethtool_stats(port_priv->mac, data + i);
+
+ mutex_unlock(&port_priv->mac_lock);
}
const struct ethtool_ops dpaa2_switch_port_ethtool_ops = {
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
index 3b0963d95f67..0472e24191ad 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.c
@@ -602,8 +602,11 @@ static int dpaa2_switch_port_link_state_update(struct net_device *netdev)
/* When we manage the MAC/PHY using phylink there is no need
* to manually update the netif_carrier.
+ * We can avoid locking because we are called from the "link changed"
+ * IRQ handler, which is the same as the "endpoint changed" IRQ handler
+ * (the writer to port_priv->mac), so we cannot race with it.
*/
- if (dpaa2_switch_port_is_type_phy(port_priv))
+ if (dpaa2_mac_is_type_phy(port_priv->mac))
return 0;
/* Interrupts are received even though no one issued an 'ifconfig up'
@@ -683,6 +686,8 @@ static int dpaa2_switch_port_open(struct net_device *netdev)
struct ethsw_core *ethsw = port_priv->ethsw_data;
int err;
+ mutex_lock(&port_priv->mac_lock);
+
if (!dpaa2_switch_port_is_type_phy(port_priv)) {
/* Explicitly set carrier off, otherwise
* netif_carrier_ok() will return true and cause 'ip link show'
@@ -696,6 +701,7 @@ static int dpaa2_switch_port_open(struct net_device *netdev)
port_priv->ethsw_data->dpsw_handle,
port_priv->idx);
if (err) {
+ mutex_unlock(&port_priv->mac_lock);
netdev_err(netdev, "dpsw_if_enable err %d\n", err);
return err;
}
@@ -705,6 +711,8 @@ static int dpaa2_switch_port_open(struct net_device *netdev)
if (dpaa2_switch_port_is_type_phy(port_priv))
dpaa2_mac_start(port_priv->mac);
+ mutex_unlock(&port_priv->mac_lock);
+
return 0;
}
@@ -714,6 +722,8 @@ static int dpaa2_switch_port_stop(struct net_device *netdev)
struct ethsw_core *ethsw = port_priv->ethsw_data;
int err;
+ mutex_lock(&port_priv->mac_lock);
+
if (dpaa2_switch_port_is_type_phy(port_priv)) {
dpaa2_mac_stop(port_priv->mac);
} else {
@@ -721,6 +731,8 @@ static int dpaa2_switch_port_stop(struct net_device *netdev)
netif_carrier_off(netdev);
}
+ mutex_unlock(&port_priv->mac_lock);
+
err = dpsw_if_disable(port_priv->ethsw_data->mc_io, 0,
port_priv->ethsw_data->dpsw_handle,
port_priv->idx);
@@ -1460,7 +1472,9 @@ static int dpaa2_switch_port_connect_mac(struct ethsw_port_priv *port_priv)
}
}
+ mutex_lock(&port_priv->mac_lock);
port_priv->mac = mac;
+ mutex_unlock(&port_priv->mac_lock);
return 0;
@@ -1473,9 +1487,12 @@ static int dpaa2_switch_port_connect_mac(struct ethsw_port_priv *port_priv)
static void dpaa2_switch_port_disconnect_mac(struct ethsw_port_priv *port_priv)
{
- struct dpaa2_mac *mac = port_priv->mac;
+ struct dpaa2_mac *mac;
+ mutex_lock(&port_priv->mac_lock);
+ mac = port_priv->mac;
port_priv->mac = NULL;
+ mutex_unlock(&port_priv->mac_lock);
if (!mac)
return;
@@ -1494,6 +1511,7 @@ static irqreturn_t dpaa2_switch_irq0_handler_thread(int irq_num, void *arg)
struct ethsw_port_priv *port_priv;
u32 status = ~0;
int err, if_id;
+ bool had_mac;
err = dpsw_get_irq_status(ethsw->mc_io, 0, ethsw->dpsw_handle,
DPSW_IRQ_INDEX_IF, &status);
@@ -1512,7 +1530,12 @@ static irqreturn_t dpaa2_switch_irq0_handler_thread(int irq_num, void *arg)
if (status & DPSW_IRQ_EVENT_ENDPOINT_CHANGED) {
rtnl_lock();
- if (dpaa2_switch_port_has_mac(port_priv))
+ /* We can avoid locking because the "endpoint changed" IRQ
+ * handler is the only one who changes priv->mac at runtime,
+ * so we are not racing with anyone.
+ */
+ had_mac = !!port_priv->mac;
+ if (had_mac)
dpaa2_switch_port_disconnect_mac(port_priv);
else
dpaa2_switch_port_connect_mac(port_priv);
@@ -3255,6 +3278,8 @@ static int dpaa2_switch_probe_port(struct ethsw_core *ethsw,
port_priv->netdev = port_netdev;
port_priv->ethsw_data = ethsw;
+ mutex_init(&port_priv->mac_lock);
+
port_priv->idx = port_idx;
port_priv->stp_state = BR_STATE_FORWARDING;
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.h b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.h
index 9898073abe01..42b3ca73f55d 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.h
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-switch.h
@@ -161,6 +161,8 @@ struct ethsw_port_priv {
struct dpaa2_switch_filter_block *filter_block;
struct dpaa2_mac *mac;
+ /* Protects against changes to port_priv->mac */
+ struct mutex mac_lock;
};
/* Switch data */
--
2.34.1