Commit 35626012 authored by Vivian Wang's avatar Vivian Wang Committed by Jakub Kicinski
Browse files

net: spacemit: Make stats_lock softirq-safe 



While most of the statistics functions (emac_get_stats64() and such) are
called with softirqs enabled, emac_stats_timer() is, as its name
suggests, also called from a timer, i.e. called in softirq context.

All of these take stats_lock. Therefore, make stats_lock softirq-safe by
changing spin_lock() into spin_lock_bh() for the functions that get
statistics.

Also, instead of directly calling emac_stats_timer() in emac_up() and
emac_resume(), set the timer to trigger instead, so that
emac_stats_timer() is only called from the timer. It will keep using
spin_lock().

This fixes a lockdep warning, and potential deadlock when stats_timer is
triggered in the middle of getting statistics.

Fixes: bfec6d7f ("net: spacemit: Add K1 Ethernet MAC")
Reported-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/all/a52c0cf5-0444-41aa-b061-a0a1d72b02fe@samsung.com/


Signed-off-by: default avatarVivian Wang <wangruikang@iscas.ac.cn>
Tested-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Link: https://patch.msgid.link/20250919-k1-ethernet-fix-lock-v1-1-c8b700aa4954@iscas.ac.cn


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 4b1eb833

drivers/net/ethernet/spacemit/k1_emac.c

+15 −15
Original line number Diff line number Diff line
@@ -135,7 +135,7 @@ struct emac_priv { 
	bool flow_control_autoneg;

	u8 flow_control;



	/* Hold while touching hardware statistics */

	/* Softirq-safe, hold while touching hardware statistics */

	spinlock_t stats_lock;

};
@@ -1239,7 +1239,7 @@ static void emac_get_stats64(struct net_device *dev, 
	/* This is the only software counter */

	storage->tx_dropped = emac_get_stat_tx_drops(priv);



	spin_lock(&priv->stats_lock);

	spin_lock_bh(&priv->stats_lock);



	emac_stats_update(priv);
@@ -1261,7 +1261,7 @@ static void emac_get_stats64(struct net_device *dev, 
	storage->rx_missed_errors = rx_stats->stats.rx_drp_fifo_full_pkts;

	storage->rx_missed_errors += rx_stats->stats.rx_truncate_fifo_full_pkts;



	spin_unlock(&priv->stats_lock);

	spin_unlock_bh(&priv->stats_lock);

}



static void emac_get_rmon_stats(struct net_device *dev,
@@ -1275,7 +1275,7 @@ static void emac_get_rmon_stats(struct net_device *dev, 


	*ranges = emac_rmon_hist_ranges;



	spin_lock(&priv->stats_lock);

	spin_lock_bh(&priv->stats_lock);



	emac_stats_update(priv);
@@ -1294,7 +1294,7 @@ static void emac_get_rmon_stats(struct net_device *dev, 
	rmon_stats->hist[5] = rx_stats->stats.rx_1024_1518_pkts;

	rmon_stats->hist[6] = rx_stats->stats.rx_1519_plus_pkts;



	spin_unlock(&priv->stats_lock);

	spin_unlock_bh(&priv->stats_lock);

}



static void emac_get_eth_mac_stats(struct net_device *dev,
@@ -1307,7 +1307,7 @@ static void emac_get_eth_mac_stats(struct net_device *dev, 
	tx_stats = &priv->tx_stats;

	rx_stats = &priv->rx_stats;



	spin_lock(&priv->stats_lock);

	spin_lock_bh(&priv->stats_lock);



	emac_stats_update(priv);
@@ -1325,7 +1325,7 @@ static void emac_get_eth_mac_stats(struct net_device *dev, 
	mac_stats->FramesAbortedDueToXSColls =

		tx_stats->stats.tx_excessclsn_pkts;



	spin_unlock(&priv->stats_lock);

	spin_unlock_bh(&priv->stats_lock);

}



static void emac_get_pause_stats(struct net_device *dev,
@@ -1338,14 +1338,14 @@ static void emac_get_pause_stats(struct net_device *dev, 
	tx_stats = &priv->tx_stats;

	rx_stats = &priv->rx_stats;



	spin_lock(&priv->stats_lock);

	spin_lock_bh(&priv->stats_lock);



	emac_stats_update(priv);



	pause_stats->tx_pause_frames = tx_stats->stats.tx_pause_pkts;

	pause_stats->rx_pause_frames = rx_stats->stats.rx_pause_pkts;



	spin_unlock(&priv->stats_lock);

	spin_unlock_bh(&priv->stats_lock);

}



/* Other statistics that are not derivable from standard statistics */
@@ -1393,14 +1393,14 @@ static void emac_get_ethtool_stats(struct net_device *dev, 
	u64 *rx_stats = (u64 *)&priv->rx_stats;

	int i;



	spin_lock(&priv->stats_lock);

	spin_lock_bh(&priv->stats_lock);



	emac_stats_update(priv);



	for (i = 0; i < ARRAY_SIZE(emac_ethtool_rx_stats); i++)

		data[i] = rx_stats[emac_ethtool_rx_stats[i].offset];



	spin_unlock(&priv->stats_lock);

	spin_unlock_bh(&priv->stats_lock);

}



static int emac_ethtool_get_regs_len(struct net_device *dev)
@@ -1769,7 +1769,7 @@ static int emac_up(struct emac_priv *priv) 


	netif_start_queue(ndev);



	emac_stats_timer(&priv->stats_timer);

	mod_timer(&priv->stats_timer, jiffies);



	return 0;
@@ -1807,14 +1807,14 @@ static int emac_down(struct emac_priv *priv) 


	/* Update and save current stats, see emac_stats_update() for usage */



	spin_lock(&priv->stats_lock);

	spin_lock_bh(&priv->stats_lock);



	emac_stats_update(priv);



	priv->tx_stats_off = priv->tx_stats;

	priv->rx_stats_off = priv->rx_stats;



	spin_unlock(&priv->stats_lock);

	spin_unlock_bh(&priv->stats_lock);



	pm_runtime_put_sync(&pdev->dev);

	return 0;
@@ -2111,7 +2111,7 @@ static int emac_resume(struct device *dev) 


	netif_device_attach(ndev);



	emac_stats_timer(&priv->stats_timer);

	mod_timer(&priv->stats_timer, jiffies);



	return 0;

}