[PATCH net-next v1 14/21] net: usb: lan78xx: Add error handling to lan78xx_get_regs

[Oleksij Rempel]

Update `lan78xx_get_regs` to handle errors during register and PHY
reads.  Log warnings for failed reads and exit the function early if an
error occurs.  This ensures that invalid data is not returned to users.

Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
 drivers/net/usb/lan78xx.c | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 5d318ff8b33d..62445aced7c6 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -2112,20 +2112,35 @@ static void
 lan78xx_get_regs(struct net_device *netdev, struct ethtool_regs *regs,
 		 void *buf)
 {
-	u32 *data = buf;
-	int i, j;
 	struct lan78xx_net *dev = netdev_priv(netdev);
+	u32 *data = buf;
+	int i, j, ret;
 
 	/* Read Device/MAC registers */
-	for (i = 0; i < ARRAY_SIZE(lan78xx_regs); i++)
-		lan78xx_read_reg(dev, lan78xx_regs[i], &data[i]);
+	for (i = 0; i < ARRAY_SIZE(lan78xx_regs); i++) {
+		ret = lan78xx_read_reg(dev, lan78xx_regs[i], &data[i]);
+		if (ret < 0) {
+			netdev_warn(dev->net,
+				    "failed to read register 0x%08x\n",
+				    lan78xx_regs[i]);
+			return;
+		}
+	}
 
 	if (!netdev->phydev)
 		return;
 
 	/* Read PHY registers */
-	for (j = 0; j < 32; i++, j++)
-		data[i] = phy_read(netdev->phydev, j);
+	for (j = 0; j < 32; i++, j++) {
+		ret = phy_read(netdev->phydev, j);
+		if (ret < 0) {
+			netdev_warn(dev->net,
+				    "failed to read PHY register 0x%02x\n", j);
+			return;
+		}
+
+		data[i] = ret;
+	}
 }
 
 static const struct ethtool_ops lan78xx_ethtool_ops = {
-- 
2.39.5