net: phy: realtek: net: Fix less than zero comparison of a u16

mainline inclusion
from mainline-v5.14-rc1
commit f25247d8
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4H7E6
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f25247d88708

----------------------------------------------------------------------

The comparisons of the u16 values priv->phycr1 and priv->phycr2 to less
than zero always false because they are unsigned. Fix this by using an
int for the assignment and less than zero check.

Addresses-Coverity: ("Unsigned compared against 0")
Fixes: 0a4355c2 ("net: phy: realtek: add dt property to disable CLKOUT clock")
Fixes: d90db36a ("net: phy: realtek: add dt property to enable ALDPS mode")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Reviewed-by: NYongxin Li <liyongxin1@huawei.com>
Signed-off-by: NJunxin Chen <chenjunxin1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/net/phy/realtek.c

@@ -85,24 +85,25 @@ static int rtl821x_probe(struct phy_device *phydev)
 {
 	struct device *dev = &phydev->mdio.dev;
 	struct rtl821x_priv *priv;
+	int ret;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
-	priv->phycr1 = phy_read_paged(phydev, 0xa43, RTL8211F_PHYCR1);
-	if (priv->phycr1 < 0)
-		return priv->phycr1;
+	ret = phy_read_paged(phydev, 0xa43, RTL8211F_PHYCR1);
+	if (ret < 0)
+		return ret;
 
-	priv->phycr1 &= (RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF);
+	priv->phycr1 = ret & (RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF);
 	if (of_property_read_bool(dev->of_node, "realtek,aldps-enable"))
 		priv->phycr1 |= RTL8211F_ALDPS_PLL_OFF | RTL8211F_ALDPS_ENABLE | RTL8211F_ALDPS_XTAL_OFF;
 
-	priv->phycr2 = phy_read_paged(phydev, 0xa43, RTL8211F_PHYCR2);
-	if (priv->phycr2 < 0)
-		return priv->phycr2;
+	ret = phy_read_paged(phydev, 0xa43, RTL8211F_PHYCR2);
+	if (ret < 0)
+		return ret;
 
-	priv->phycr2 &= RTL8211F_CLKOUT_EN;
+	priv->phycr2 = ret & RTL8211F_CLKOUT_EN;
 	if (of_property_read_bool(dev->of_node, "realtek,clkout-disable"))
 		priv->phycr2 &= ~RTL8211F_CLKOUT_EN;