net: renesas: rswitch: Add spin lock protection for irq {un}mask

Add spin lock protection for irq {un}mask registers' control.

After napi_complete_done() and this protection were applied,
a lot of redundant interrupts no longer occur.

For example: when "iperf3 -c <ipaddr> -R" on R-Car S4-8 Spider
 Before the patches are applied: about 800,000 times happened
 After the patches were applied: about 100,000 times happened

Fixes: 3590918b5d07 ("net: ethernet: renesas: Add support for "Ethernet Switch"")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/ethernet/renesas/rswitch.c b/drivers/net/ethernet/renesas/rswitch.c
index 26c8807d7deafcac0812b33f8db95581c6afa436..ea9186178091d5165ffcf14f5231a84d990a8e61 100644 (file)
--- a/drivers/net/ethernet/renesas/rswitch.c
+++ b/drivers/net/ethernet/renesas/rswitch.c
@@ -799,6 +799,7 @@ static int rswitch_poll(struct napi_struct *napi, int budget)
        struct net_device *ndev = napi->dev;
        struct rswitch_private *priv;
        struct rswitch_device *rdev;
+       unsigned long flags;
        int quota = budget;
 
        rdev = netdev_priv(ndev);
@@ -817,8 +818,10 @@ retry:
        netif_wake_subqueue(ndev, 0);
 
        if (napi_complete_done(napi, budget - quota)) {
+               spin_lock_irqsave(&priv->lock, flags);
                rswitch_enadis_data_irq(priv, rdev->tx_queue->index, true);
                rswitch_enadis_data_irq(priv, rdev->rx_queue->index, true);
+               spin_unlock_irqrestore(&priv->lock, flags);
        }
 
 out:
@@ -835,8 +838,10 @@ static void rswitch_queue_interrupt(struct net_device *ndev)
        struct rswitch_device *rdev = netdev_priv(ndev);
 
        if (napi_schedule_prep(&rdev->napi)) {
+               spin_lock(&rdev->priv->lock);
                rswitch_enadis_data_irq(rdev->priv, rdev->tx_queue->index, false);
                rswitch_enadis_data_irq(rdev->priv, rdev->rx_queue->index, false);
+               spin_unlock(&rdev->priv->lock);
                __napi_schedule(&rdev->napi);
        }
 }
@@ -1440,14 +1445,17 @@ static void rswitch_ether_port_deinit_all(struct rswitch_private *priv)
 static int rswitch_open(struct net_device *ndev)
 {
        struct rswitch_device *rdev = netdev_priv(ndev);
+       unsigned long flags;
 
        phy_start(ndev->phydev);
 
        napi_enable(&rdev->napi);
        netif_start_queue(ndev);
 
+       spin_lock_irqsave(&rdev->priv->lock, flags);
        rswitch_enadis_data_irq(rdev->priv, rdev->tx_queue->index, true);
        rswitch_enadis_data_irq(rdev->priv, rdev->rx_queue->index, true);
+       spin_unlock_irqrestore(&rdev->priv->lock, flags);
 
        if (bitmap_empty(rdev->priv->opened_ports, RSWITCH_NUM_PORTS))
                iowrite32(GWCA_TS_IRQ_BIT, rdev->priv->addr + GWTSDIE);
@@ -1461,6 +1469,7 @@ static int rswitch_stop(struct net_device *ndev)
 {
        struct rswitch_device *rdev = netdev_priv(ndev);
        struct rswitch_gwca_ts_info *ts_info, *ts_info2;
+       unsigned long flags;
 
        netif_tx_stop_all_queues(ndev);
        bitmap_clear(rdev->priv->opened_ports, rdev->port, 1);
@@ -1476,8 +1485,10 @@ static int rswitch_stop(struct net_device *ndev)
                kfree(ts_info);
        }
 
+       spin_lock_irqsave(&rdev->priv->lock, flags);
        rswitch_enadis_data_irq(rdev->priv, rdev->tx_queue->index, false);
        rswitch_enadis_data_irq(rdev->priv, rdev->rx_queue->index, false);
+       spin_unlock_irqrestore(&rdev->priv->lock, flags);
 
        phy_stop(ndev->phydev);
        napi_disable(&rdev->napi);
@@ -1887,6 +1898,7 @@ static int renesas_eth_sw_probe(struct platform_device *pdev)
        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;
+       spin_lock_init(&priv->lock);
 
        attr = soc_device_match(rswitch_soc_no_speed_change);
        if (attr)

diff --git a/drivers/net/ethernet/renesas/rswitch.h b/drivers/net/ethernet/renesas/rswitch.h
index 54f397effbc6b1ee17f669f6411776634a4ff586..f0c16a37ea55858002a51a4984e77a34dd94e512 100644 (file)
--- a/drivers/net/ethernet/renesas/rswitch.h
+++ b/drivers/net/ethernet/renesas/rswitch.h
@@ -1011,6 +1011,8 @@ struct rswitch_private {
        struct rswitch_etha etha[RSWITCH_NUM_PORTS];
        struct rswitch_mfwd mfwd;
 
+       spinlock_t lock;        /* lock interrupt registers' control */
+
        bool etha_no_runtime_change;
        bool gwca_halt;
 };