The dpaa2 architecture permits dynamic connections between objects on
the fsl-mc bus, specifically between a DPNI object (represented by a
struct net_device) and a DPMAC object (represented by a struct phylink).
The DPNI driver is notified when those connections are created/broken
through the dpni_irq0_handler_thread() method. To ensure that ethtool
operations, as well as netdev up/down operations serialize with the
connection/disconnection of the DPNI with a DPMAC,
dpni_irq0_handler_thread() takes the rtnl_lock() to block those other
operations from taking place.
There is code called by dpaa2_mac_connect() which wants to acquire the
rtnl_mutex once again, see phylink_create() -> phylink_register_sfp() ->
sfp_bus_add_upstream() -> rtnl_lock(). So the strategy doesn't quite
work out, even though it's fairly simple.
Create a different strategy, where all code paths in the dpaa2-eth
driver access priv->mac only while they are holding priv->mac_lock.
The phylink instance is not created or connected to the PHY under the
priv->mac_lock, but only assigned to priv->mac then. This will eliminate
the reliance on the rtnl_mutex.
Add lockdep annotations and put comments where holding the lock is not
necessary, and priv->mac can be dereferenced freely.
Signed-off-by: Vladimir Oltean <[email protected]>
---
.../net/ethernet/freescale/dpaa2/dpaa2-eth.c | 43 ++++++++++++--
.../net/ethernet/freescale/dpaa2/dpaa2-eth.h | 6 ++
.../ethernet/freescale/dpaa2/dpaa2-ethtool.c | 58 +++++++++++++++----
3 files changed, 91 insertions(+), 16 deletions(-)
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
index b77d292cd960..3ed54c147e98 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
@@ -2147,8 +2147,11 @@ static int dpaa2_eth_link_state_update(struct dpaa2_eth_priv *priv)
/* 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 priv->mac), so we cannot race with it.
*/
- if (dpaa2_eth_is_type_phy(priv))
+ if (dpaa2_mac_is_type_phy(priv->mac))
goto out;
/* Chech link state; speed / duplex changes are not treated yet */
@@ -2179,6 +2182,8 @@ static int dpaa2_eth_open(struct net_device *net_dev)
dpaa2_eth_seed_pools(priv);
+ mutex_lock(&priv->mac_lock);
+
if (!dpaa2_eth_is_type_phy(priv)) {
/* We'll only start the txqs when the link is actually ready;
* make sure we don't race against the link up notification,
@@ -2197,6 +2202,7 @@ static int dpaa2_eth_open(struct net_device *net_dev)
err = dpni_enable(priv->mc_io, 0, priv->mc_token);
if (err < 0) {
+ mutex_unlock(&priv->mac_lock);
netdev_err(net_dev, "dpni_enable() failed\n");
goto enable_err;
}
@@ -2204,6 +2210,8 @@ static int dpaa2_eth_open(struct net_device *net_dev)
if (dpaa2_eth_is_type_phy(priv))
dpaa2_mac_start(priv->mac);
+ mutex_unlock(&priv->mac_lock);
+
return 0;
enable_err:
@@ -2275,6 +2283,8 @@ static int dpaa2_eth_stop(struct net_device *net_dev)
int dpni_enabled = 0;
int retries = 10;
+ mutex_lock(&priv->mac_lock);
+
if (dpaa2_eth_is_type_phy(priv)) {
dpaa2_mac_stop(priv->mac);
} else {
@@ -2282,6 +2292,8 @@ static int dpaa2_eth_stop(struct net_device *net_dev)
netif_carrier_off(net_dev);
}
+ mutex_unlock(&priv->mac_lock);
+
/* On dpni_disable(), the MC firmware will:
* - stop MAC Rx and wait for all Rx frames to be enqueued to software
* - cut off WRIOP dequeues from egress FQs and wait until transmission
@@ -2607,12 +2619,20 @@ static int dpaa2_eth_ts_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
static int dpaa2_eth_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
struct dpaa2_eth_priv *priv = netdev_priv(dev);
+ int err;
if (cmd == SIOCSHWTSTAMP)
return dpaa2_eth_ts_ioctl(dev, rq, cmd);
- if (dpaa2_eth_is_type_phy(priv))
- return phylink_mii_ioctl(priv->mac->phylink, rq, cmd);
+ mutex_lock(&priv->mac_lock);
+
+ if (dpaa2_eth_is_type_phy(priv)) {
+ err = phylink_mii_ioctl(priv->mac->phylink, rq, cmd);
+ mutex_unlock(&priv->mac_lock);
+ return err;
+ }
+
+ mutex_unlock(&priv->mac_lock);
return -EOPNOTSUPP;
}
@@ -4639,7 +4659,9 @@ static int dpaa2_eth_connect_mac(struct dpaa2_eth_priv *priv)
}
}
+ mutex_lock(&priv->mac_lock);
priv->mac = mac;
+ mutex_unlock(&priv->mac_lock);
return 0;
@@ -4652,9 +4674,12 @@ static int dpaa2_eth_connect_mac(struct dpaa2_eth_priv *priv)
static void dpaa2_eth_disconnect_mac(struct dpaa2_eth_priv *priv)
{
- struct dpaa2_mac *mac = priv->mac;
+ struct dpaa2_mac *mac;
+ mutex_lock(&priv->mac_lock);
+ mac = priv->mac;
priv->mac = NULL;
+ mutex_unlock(&priv->mac_lock);
if (!mac)
return;
@@ -4673,6 +4698,7 @@ static irqreturn_t dpni_irq0_handler_thread(int irq_num, void *arg)
struct fsl_mc_device *dpni_dev = to_fsl_mc_device(dev);
struct net_device *net_dev = dev_get_drvdata(dev);
struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
+ bool had_mac;
int err;
err = dpni_get_irq_status(dpni_dev->mc_io, 0, dpni_dev->mc_handle,
@@ -4690,7 +4716,12 @@ static irqreturn_t dpni_irq0_handler_thread(int irq_num, void *arg)
dpaa2_eth_update_tx_fqids(priv);
rtnl_lock();
- if (dpaa2_eth_has_mac(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 = !!priv->mac;
+ if (had_mac)
dpaa2_eth_disconnect_mac(priv);
else
dpaa2_eth_connect_mac(priv);
@@ -4792,6 +4823,8 @@ static int dpaa2_eth_probe(struct fsl_mc_device *dpni_dev)
priv->net_dev = net_dev;
SET_NETDEV_DEVLINK_PORT(net_dev, &priv->devlink_port);
+ mutex_init(&priv->mac_lock);
+
priv->iommu_domain = iommu_get_domain_for_dev(dev);
priv->tx_tstamp_type = HWTSTAMP_TX_OFF;
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
index 04270ae44d84..d56d7a13262e 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h
@@ -615,6 +615,8 @@ struct dpaa2_eth_priv {
#endif
struct dpaa2_mac *mac;
+ /* Serializes changes to priv->mac */
+ struct mutex mac_lock;
struct workqueue_struct *dpaa2_ptp_wq;
struct work_struct tx_onestep_tstamp;
struct sk_buff_head tx_skbs;
@@ -768,11 +770,15 @@ static inline unsigned int dpaa2_eth_rx_head_room(struct dpaa2_eth_priv *priv)
static inline bool dpaa2_eth_is_type_phy(struct dpaa2_eth_priv *priv)
{
+ lockdep_assert_held(&priv->mac_lock);
+
return dpaa2_mac_is_type_phy(priv->mac);
}
static inline bool dpaa2_eth_has_mac(struct dpaa2_eth_priv *priv)
{
+ lockdep_assert_held(&priv->mac_lock);
+
return priv->mac ? true : false;
}
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
index bd87aa9ef686..e80e9388c71f 100644
--- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
+++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c
@@ -85,11 +85,16 @@ static void dpaa2_eth_get_drvinfo(struct net_device *net_dev,
static int dpaa2_eth_nway_reset(struct net_device *net_dev)
{
struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
+ int err = -EOPNOTSUPP;
+
+ mutex_lock(&priv->mac_lock);
if (dpaa2_eth_is_type_phy(priv))
- return phylink_ethtool_nway_reset(priv->mac->phylink);
+ err = phylink_ethtool_nway_reset(priv->mac->phylink);
+
+ mutex_unlock(&priv->mac_lock);
- return -EOPNOTSUPP;
+ return err;
}
static int
@@ -97,10 +102,18 @@ dpaa2_eth_get_link_ksettings(struct net_device *net_dev,
struct ethtool_link_ksettings *link_settings)
{
struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
+ int err;
- if (dpaa2_eth_is_type_phy(priv))
- return phylink_ethtool_ksettings_get(priv->mac->phylink,
- link_settings);
+ mutex_lock(&priv->mac_lock);
+
+ if (dpaa2_eth_is_type_phy(priv)) {
+ err = phylink_ethtool_ksettings_get(priv->mac->phylink,
+ link_settings);
+ mutex_unlock(&priv->mac_lock);
+ return err;
+ }
+
+ mutex_unlock(&priv->mac_lock);
link_settings->base.autoneg = AUTONEG_DISABLE;
if (!(priv->link_state.options & DPNI_LINK_OPT_HALF_DUPLEX))
@@ -115,11 +128,17 @@ dpaa2_eth_set_link_ksettings(struct net_device *net_dev,
const struct ethtool_link_ksettings *link_settings)
{
struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
+ int err = -EOPNOTSUPP;
- if (!dpaa2_eth_is_type_phy(priv))
- return -EOPNOTSUPP;
+ mutex_lock(&priv->mac_lock);
+
+ if (dpaa2_eth_is_type_phy(priv))
+ err = phylink_ethtool_ksettings_set(priv->mac->phylink,
+ link_settings);
- return phylink_ethtool_ksettings_set(priv->mac->phylink, link_settings);
+ mutex_unlock(&priv->mac_lock);
+
+ return err;
}
static void dpaa2_eth_get_pauseparam(struct net_device *net_dev,
@@ -128,11 +147,16 @@ static void dpaa2_eth_get_pauseparam(struct net_device *net_dev,
struct dpaa2_eth_priv *priv = netdev_priv(net_dev);
u64 link_options = priv->link_state.options;
+ mutex_lock(&priv->mac_lock);
+
if (dpaa2_eth_is_type_phy(priv)) {
phylink_ethtool_get_pauseparam(priv->mac->phylink, pause);
+ mutex_unlock(&priv->mac_lock);
return;
}
+ mutex_unlock(&priv->mac_lock);
+
pause->rx_pause = dpaa2_eth_rx_pause_enabled(link_options);
pause->tx_pause = dpaa2_eth_tx_pause_enabled(link_options);
pause->autoneg = AUTONEG_DISABLE;
@@ -151,9 +175,17 @@ static int dpaa2_eth_set_pauseparam(struct net_device *net_dev,
return -EOPNOTSUPP;
}
- if (dpaa2_eth_is_type_phy(priv))
- return phylink_ethtool_set_pauseparam(priv->mac->phylink,
- pause);
+ mutex_lock(&priv->mac_lock);
+
+ if (dpaa2_eth_is_type_phy(priv)) {
+ err = phylink_ethtool_set_pauseparam(priv->mac->phylink,
+ pause);
+ mutex_unlock(&priv->mac_lock);
+ return err;
+ }
+
+ mutex_unlock(&priv->mac_lock);
+
if (pause->autoneg)
return -EOPNOTSUPP;
@@ -309,8 +341,12 @@ static void dpaa2_eth_get_ethtool_stats(struct net_device *net_dev,
}
*(data + i++) = buf_cnt_total;
+ mutex_lock(&priv->mac_lock);
+
if (dpaa2_eth_has_mac(priv))
dpaa2_mac_get_ethtool_stats(priv->mac, data + i);
+
+ mutex_unlock(&priv->mac_lock);
}
static int dpaa2_eth_prep_eth_rule(struct ethhdr *eth_value, struct ethhdr *eth_mask,
--
2.34.1