net: ti: icssg-prueth: Add lock to stats

[ Upstream commit 47a9b5e52abd2b717dfc8b9460589f89936d93cf ]

Currently the API emac_update_hardware_stats() reads different ICSSG
stats without any lock protection.

This API gets called by .ndo_get_stats64() which is only under RCU
protection and nothing else. Add lock to this API so that the reading of
statistics happens during lock.

Fixes: c1e10d5dc7 ("net: ti: icssg-prueth: Add ICSSG Stats")
Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250314102721.1394366-1-danishanwar@ti.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/net/ethernet/ti/icssg/icssg_prueth.c

@@ -1555,6 +1555,7 @@ static int prueth_probe(struct platform_device *pdev)
 	}
 
 	spin_lock_init(&prueth->vtbl_lock);
+	spin_lock_init(&prueth->stats_lock);
 	/* setup netdev interfaces */
 	if (eth0_node) {
 		ret = prueth_netdev_init(prueth, eth0_node);

drivers/net/ethernet/ti/icssg/icssg_prueth.h

@@ -297,6 +297,8 @@ struct prueth {
 	int default_vlan;
 	/** @vtbl_lock: Lock for vtbl in shared memory */
 	spinlock_t vtbl_lock;
+	/** @stats_lock: Lock for reading icssg stats */
+	spinlock_t stats_lock;
 };
 
 struct emac_tx_ts_response {

drivers/net/ethernet/ti/icssg/icssg_stats.c

@@ -26,6 +26,8 @@ void emac_update_hardware_stats(struct prueth_emac *emac)
 	u32 val, reg;
 	int i;
 
+	spin_lock(&prueth->stats_lock);
+
 	for (i = 0; i < ARRAY_SIZE(icssg_all_miig_stats); i++) {
 		regmap_read(prueth->miig_rt,
 			    base + icssg_all_miig_stats[i].offset,
@@ -51,6 +53,8 @@ void emac_update_hardware_stats(struct prueth_emac *emac)
 			emac->pa_stats[i] += val;
 		}
 	}
+
+	spin_unlock(&prueth->stats_lock);
 }
 
 void icssg_stats_work_handler(struct work_struct *work)