netdev - [PATCH net 2/2] net: ethernet: ftgmac100: fix NULL phy usage on device remove

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Message-Id: <20241028-ftgmac-fixes-v1-2-b334a507be6c@codeconstruct.com.au>
Date: Mon, 28 Oct 2024 12:54:11 +0800
From: Jeremy Kerr <jk@...econstruct.com.au>
To: Andrew Lunn <andrew+netdev@...n.ch>, 
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
 Joel Stanley <joel@....id.au>, Jacky Chou <jacky_chou@...eedtech.com>, 
 Jacob Keller <jacob.e.keller@...el.com>
Cc: netdev@...r.kernel.org
Subject: [PATCH net 2/2] net: ethernet: ftgmac100: fix NULL phy usage on
 device remove

Commit e24a6c874601 ("net: ftgmac100: Get link speed and duplex for
NC-SI") introduced a fixed phydev attached to the ftgmac netdev for ncsi
configurations, cleaned up on remove as:

    phy_disconnect(netdev->phydev);

    /* ... */

    if (priv->use_ncsi)
        fixed_phy_unregister(netdev->phydev);

However, phy_disconnect() will clear the netdev's ->phydev pointer, so
the fixed_phy_unregister() will always be invoked with a null pointer.

Use a temporary for the phydev, rather than expecting the netdev->phydev
point to be valid over the phy_disconnect().

Fixes: e24a6c874601 ("net: ftgmac100: Get link speed and duplex for NC-SI")
Signed-off-by: Jeremy Kerr <jk@...econstruct.com.au>
---
 drivers/net/ethernet/faraday/ftgmac100.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 9caee68468ff5f71d7ea63a0c8c9ec2be4a718bc..c6ed7ed0e2389a45a671b85ae60936df99458cd1 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -1730,16 +1730,17 @@ static int ftgmac100_setup_mdio(struct net_device *netdev)
 static void ftgmac100_phy_disconnect(struct net_device *netdev)
 {
 	struct ftgmac100 *priv = netdev_priv(netdev);
+	struct phy_device *phydev = netdev->phydev;

-	if (!netdev->phydev)
+	if (!phydev)
 		return;

-	phy_disconnect(netdev->phydev);
+	phy_disconnect(phydev);
 	if (of_phy_is_fixed_link(priv->dev->of_node))
 		of_phy_deregister_fixed_link(priv->dev->of_node);

 	if (priv->use_ncsi)
-		fixed_phy_unregister(netdev->phydev);
+		fixed_phy_unregister(phydev);
 }

 static void ftgmac100_destroy_mdio(struct net_device *netdev)

-- 
2.39.2