linux-kernel - [PATCH 5.4 40/61] net: mdio-mux: Don't ignore memory allocation errors

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Message-Id: <20210824170106.710221-41-sashal@kernel.org>
Date:   Tue, 24 Aug 2021 13:00:45 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Saravana Kannan <saravanak@...gle.com>,
        Andrew Lunn <andrew@...n.ch>, Marc Zyngier <maz@...nel.org>,
        Kevin Hilman <khilman@...libre.com>,
        "David S . Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 40/61] net: mdio-mux: Don't ignore memory allocation errors

From: Saravana Kannan <saravanak@...gle.com>

[ Upstream commit 99d81e942474cc7677d12f673f42a7ea699e2589 ]

If we are seeing memory allocation errors, don't try to continue
registering child mdiobus devices. It's unlikely they'll succeed.

Fixes: 342fa1964439 ("mdio: mux: make child bus walking more permissive and errors more verbose")
Signed-off-by: Saravana Kannan <saravanak@...gle.com>
Reviewed-by: Andrew Lunn <andrew@...n.ch>
Acked-by: Marc Zyngier <maz@...nel.org>
Tested-by: Marc Zyngier <maz@...nel.org>
Acked-by: Kevin Hilman <khilman@...libre.com>
Tested-by: Kevin Hilman <khilman@...libre.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/net/phy/mdio-mux.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/drivers/net/phy/mdio-mux.c b/drivers/net/phy/mdio-mux.c
index 6a1d3540210b..c96ef3b3fa3a 100644
--- a/drivers/net/phy/mdio-mux.c
+++ b/drivers/net/phy/mdio-mux.c
@@ -82,6 +82,17 @@ out:
 
 static int parent_count;
 
+static void mdio_mux_uninit_children(struct mdio_mux_parent_bus *pb)
+{
+	struct mdio_mux_child_bus *cb = pb->children;
+
+	while (cb) {
+		mdiobus_unregister(cb->mii_bus);
+		mdiobus_free(cb->mii_bus);
+		cb = cb->next;
+	}
+}
+
 int mdio_mux_init(struct device *dev,
 		  struct device_node *mux_node,
 		  int (*switch_fn)(int cur, int desired, void *data),
@@ -144,7 +155,7 @@ int mdio_mux_init(struct device *dev,
 		cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
 		if (!cb) {
 			ret_val = -ENOMEM;
-			continue;
+			goto err_loop;
 		}
 		cb->bus_number = v;
 		cb->parent = pb;
@@ -152,8 +163,7 @@ int mdio_mux_init(struct device *dev,
 		cb->mii_bus = mdiobus_alloc();
 		if (!cb->mii_bus) {
 			ret_val = -ENOMEM;
-			devm_kfree(dev, cb);
-			continue;
+			goto err_loop;
 		}
 		cb->mii_bus->priv = cb;
 
@@ -182,6 +192,10 @@ int mdio_mux_init(struct device *dev,
 
 	dev_err(dev, "Error: No acceptable child buses found\n");
 	devm_kfree(dev, pb);
+
+err_loop:
+	mdio_mux_uninit_children(pb);
+	of_node_put(child_bus_node);
 err_pb_kz:
 	put_device(&parent_bus->dev);
 err_parent_bus:
@@ -193,14 +207,8 @@ EXPORT_SYMBOL_GPL(mdio_mux_init);
 void mdio_mux_uninit(void *mux_handle)
 {
 	struct mdio_mux_parent_bus *pb = mux_handle;
-	struct mdio_mux_child_bus *cb = pb->children;
-
-	while (cb) {
-		mdiobus_unregister(cb->mii_bus);
-		mdiobus_free(cb->mii_bus);
-		cb = cb->next;
-	}
 
+	mdio_mux_uninit_children(pb);
 	put_device(&pb->mii_bus->dev);
 }
 EXPORT_SYMBOL_GPL(mdio_mux_uninit);
-- 
2.30.2