From 5e448a17dfa2e95166534df7f677a3694ef6187d Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Tue, 29 Nov 2022 16:12:19 +0200 Subject: [PATCH 12/14] net: dpaa2-eth: serialize changes to priv->mac with a mutex 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 Reviewed-by: Ioana Ciornei Tested-by: Ioana Ciornei Signed-off-by: Paolo Abeni --- .../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(-) --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c @@ -2020,8 +2020,11 @@ static int dpaa2_eth_link_state_update(s /* 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 */ @@ -2060,6 +2063,8 @@ static int dpaa2_eth_open(struct net_dev priv->dpbp_dev->obj_desc.id, priv->bpid); } + 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, @@ -2078,6 +2083,7 @@ static int dpaa2_eth_open(struct 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; } @@ -2085,6 +2091,8 @@ static int dpaa2_eth_open(struct net_dev if (dpaa2_eth_is_type_phy(priv)) dpaa2_mac_start(priv->mac); + mutex_unlock(&priv->mac_lock); + return 0; enable_err: @@ -2156,6 +2164,8 @@ static int dpaa2_eth_stop(struct 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 { @@ -2163,6 +2173,8 @@ static int dpaa2_eth_stop(struct 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 @@ -2488,12 +2500,20 @@ static int dpaa2_eth_ts_ioctl(struct net 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; } @@ -4453,7 +4473,9 @@ static int dpaa2_eth_connect_mac(struct goto err_close_mac; } + mutex_lock(&priv->mac_lock); priv->mac = mac; + mutex_unlock(&priv->mac_lock); return 0; @@ -4466,9 +4488,12 @@ err_free_mac: 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; @@ -4487,6 +4512,7 @@ static irqreturn_t dpni_irq0_handler_thr 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, @@ -4504,7 +4530,12 @@ static irqreturn_t dpni_irq0_handler_thr 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); @@ -4605,6 +4636,8 @@ static int dpaa2_eth_probe(struct fsl_mc priv = netdev_priv(net_dev); priv->net_dev = net_dev; + mutex_init(&priv->mac_lock); + priv->iommu_domain = iommu_get_domain_for_dev(dev); priv->tx_tstamp_type = HWTSTAMP_TX_OFF; --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.h @@ -580,6 +580,8 @@ 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; @@ -733,11 +735,15 @@ static inline unsigned int dpaa2_eth_rx_ 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; } --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-ethtool.c @@ -86,11 +86,16 @@ static void dpaa2_eth_get_drvinfo(struct 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 @@ -98,10 +103,18 @@ dpaa2_eth_get_link_ksettings(struct net_ 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)) @@ -116,11 +129,17 @@ dpaa2_eth_set_link_ksettings(struct net_ 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, @@ -129,11 +148,16 @@ static void dpaa2_eth_get_pauseparam(str 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; @@ -152,9 +176,17 @@ static int dpaa2_eth_set_pauseparam(stru 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( } *(data + i++) = buf_cnt; + 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,