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net: cadence: macb: Synchronize stats calculations

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Stats calculations involve a RMW to add the stat update to the existing
value. This is currently not protected by any synchronization mechanism,
so data races are possible. Add a spinlock to protect the update. The
reader side could be protected using u64_stats, but we would still need
a spinlock for the update side anyway. And we always do an update
immediately before reading the stats anyway.

Fixes: 89e5785fc8 ("[PATCH] Atmel MACB ethernet driver")
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Link: https://patch.msgid.link/20250220162950.95941-1-sean.anderson@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Sean Anderson 2025-02-20 11:29:50 -05:00 • committed by Jakub Kicinski
parent 27843ce6ba
commit fa52f15c74
2 changed files with 12 additions and 2 deletions
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2
drivers/net/ethernet/cadence/macb.h
View file

@ -1279,6 +1279,8 @@ struct macb {
struct clk *rx_clk;
struct clk *tsu_clk;
struct net_device *dev;
/* Protects hw_stats and ethtool_stats */
spinlock_t stats_lock;
union {
struct macb_stats macb;
struct gem_stats gem;

12
drivers/net/ethernet/cadence/macb_main.c
View file

@ -1978,10 +1978,12 @@ static irqreturn_t macb_interrupt(int irq, void *dev_id)
if (status & MACB_BIT(ISR_ROVR)) {
/* We missed at least one packet */
spin_lock(&bp->stats_lock);
if (macb_is_gem(bp))
bp->hw_stats.gem.rx_overruns++;
else
bp->hw_stats.macb.rx_overruns++;
spin_unlock(&bp->stats_lock);
if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE)
queue_writel(queue, ISR, MACB_BIT(ISR_ROVR));
@ -3102,6 +3104,7 @@ static struct net_device_stats *gem_get_stats(struct macb *bp)
if (!netif_running(bp->dev))
return nstat;
spin_lock_irq(&bp->stats_lock);
gem_update_stats(bp);
nstat->rx_errors = (hwstat->rx_frame_check_sequence_errors +
@ -3131,6 +3134,7 @@ static struct net_device_stats *gem_get_stats(struct macb *bp)
nstat->tx_aborted_errors = hwstat->tx_excessive_collisions;
nstat->tx_carrier_errors = hwstat->tx_carrier_sense_errors;
nstat->tx_fifo_errors = hwstat->tx_underrun;
spin_unlock_irq(&bp->stats_lock);
return nstat;
}
@ -3138,12 +3142,13 @@ static struct net_device_stats *gem_get_stats(struct macb *bp)
static void gem_get_ethtool_stats(struct net_device *dev,
struct ethtool_stats *stats, u64 *data)
{
struct macb *bp;
struct macb *bp = netdev_priv(dev);
bp = netdev_priv(dev);
spin_lock_irq(&bp->stats_lock);
gem_update_stats(bp);
memcpy(data, &bp->ethtool_stats, sizeof(u64)
* (GEM_STATS_LEN + QUEUE_STATS_LEN * MACB_MAX_QUEUES));
spin_unlock_irq(&bp->stats_lock);
}
static int gem_get_sset_count(struct net_device *dev, int sset)
@ -3193,6 +3198,7 @@ static struct net_device_stats *macb_get_stats(struct net_device *dev)
return gem_get_stats(bp);
/* read stats from hardware */
spin_lock_irq(&bp->stats_lock);
macb_update_stats(bp);
/* Convert HW stats into netdevice stats */
@ -3226,6 +3232,7 @@ static struct net_device_stats *macb_get_stats(struct net_device *dev)
nstat->tx_carrier_errors = hwstat->tx_carrier_errors;
nstat->tx_fifo_errors = hwstat->tx_underruns;
/* Don't know about heartbeat or window errors... */
spin_unlock_irq(&bp->stats_lock);
return nstat;
}
@ -5097,6 +5104,7 @@ static int macb_probe(struct platform_device *pdev)
}
}
spin_lock_init(&bp->lock);
spin_lock_init(&bp->stats_lock);
/* setup capabilities */
macb_configure_caps(bp, macb_config);