net: ftgmac100: Hold reference returned by of_get_child_by_name()

stable inclusion
from stable-v5.10.132
commit 29c6a632f8193b0a4b40156afb823371d1d4c05a
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5YS3T

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=29c6a632f8193b0a4b40156afb823371d1d4c05a

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

[ Upstream commit 49b9f431 ]

In ftgmac100_probe(), we should hold the refernece returned by
of_get_child_by_name() and use it to call of_node_put() for
reference balance.

Fixes: 39bfab88 ("net: ftgmac100: Add support for DT phy-handle property")
Signed-off-by: NLiang He <windhl@126.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/net/ethernet/faraday/ftgmac100.c

@@ -1753,6 +1753,19 @@ static int ftgmac100_setup_clk(struct ftgmac100 *priv)
 	return rc;
 }
 
+static bool ftgmac100_has_child_node(struct device_node *np, const char *name)
+{
+	struct device_node *child_np = of_get_child_by_name(np, name);
+	bool ret = false;
+
+	if (child_np) {
+		ret = true;
+		of_node_put(child_np);
+	}
+
+	return ret;
+}
+
 static int ftgmac100_probe(struct platform_device *pdev)
 {
 	struct resource *res;
@@ -1866,7 +1879,7 @@ static int ftgmac100_probe(struct platform_device *pdev)
 
 		/* Display what we found */
 		phy_attached_info(phy);
-	} else if (np && !of_get_child_by_name(np, "mdio")) {
+	} else if (np && !ftgmac100_has_child_node(np, "mdio")) {
 		/* Support legacy ASPEED devicetree descriptions that decribe a
 		 * MAC with an embedded MDIO controller but have no "mdio"
 		 * child node. Automatically scan the MDIO bus for available