net: dlink: add synchronization for stats update

This patch synchronizes code that accesses from both user-space
and IRQ contexts. The `get_stats()` function can be called from both
context.

`dev->stats.tx_errors` and `dev->stats.collisions` are also updated
in the `tx_errors()` function. Therefore, these fields must also be
protected by synchronized.

There is no code that accessses `dev->stats.tx_errors` between the
previous and updated lines, so the updating point can be moved.

Signed-off-by: Moon Yeounsu <yyyynoom@gmail.com>
Link: https://patch.msgid.link/20250515075333.48290-1-yyyynoom@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/dlink/dl2k.c b/drivers/net/ethernet/dlink/dl2k.c
index 232e839a9d07192b2d733a8ce43de33017ae63fa..038a0400c1f956a5fceaa639d2895122d5e96dc4 100644 (file)
--- a/drivers/net/ethernet/dlink/dl2k.c
+++ b/drivers/net/ethernet/dlink/dl2k.c
@@ -146,6 +146,8 @@ rio_probe1 (struct pci_dev *pdev, const struct pci_device_id *ent)
        np->ioaddr = ioaddr;
        np->chip_id = chip_idx;
        np->pdev = pdev;
+
+       spin_lock_init(&np->stats_lock);
        spin_lock_init (&np->tx_lock);
        spin_lock_init (&np->rx_lock);
 
@@ -865,7 +867,6 @@ tx_error (struct net_device *dev, int tx_status)
        frame_id = (tx_status & 0xffff0000);
        printk (KERN_ERR "%s: Transmit error, TxStatus %4.4x, FrameId %d.\n",
                dev->name, tx_status, frame_id);
-       dev->stats.tx_errors++;
        /* Ttransmit Underrun */
        if (tx_status & 0x10) {
                dev->stats.tx_fifo_errors++;
@@ -902,9 +903,15 @@ tx_error (struct net_device *dev, int tx_status)
                rio_set_led_mode(dev);
                /* Let TxStartThresh stay default value */
        }
+
+       spin_lock(&np->stats_lock);
        /* Maximum Collisions */
        if (tx_status & 0x08)
                dev->stats.collisions++;
+
+       dev->stats.tx_errors++;
+       spin_unlock(&np->stats_lock);
+
        /* Restart the Tx */
        dw32(MACCtrl, dr16(MACCtrl) | TxEnable);
 }
@@ -1073,7 +1080,9 @@ get_stats (struct net_device *dev)
        int i;
 #endif
        unsigned int stat_reg;
+       unsigned long flags;
 
+       spin_lock_irqsave(&np->stats_lock, flags);
        /* All statistics registers need to be acknowledged,
           else statistic overflow could cause problems */
 
@@ -1123,6 +1132,9 @@ get_stats (struct net_device *dev)
        dr16(TCPCheckSumErrors);
        dr16(UDPCheckSumErrors);
        dr16(IPCheckSumErrors);
+
+       spin_unlock_irqrestore(&np->stats_lock, flags);
+
        return &dev->stats;
 }
 

diff --git a/drivers/net/ethernet/dlink/dl2k.h b/drivers/net/ethernet/dlink/dl2k.h
index 0e33e2eaae96062baf34e779c10bde2ac4a84f94..56aff2f0bdbfa0c660ebc79934c13b029dddd92b 100644 (file)
--- a/drivers/net/ethernet/dlink/dl2k.h
+++ b/drivers/net/ethernet/dlink/dl2k.h
@@ -372,6 +372,8 @@ struct netdev_private {
        struct pci_dev *pdev;
        void __iomem *ioaddr;
        void __iomem *eeprom_addr;
+       // To ensure synchronization when stats are updated.
+       spinlock_t stats_lock;
        spinlock_t tx_lock;
        spinlock_t rx_lock;
        unsigned int rx_buf_sz;         /* Based on MTU+slack. */