From 637249a72665b18184142453721129ffd878a263 Mon Sep 17 00:00:00 2001
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: Mon, 7 Feb 2022 18:15:52 +0200
Subject: [PATCH 1/9] net: dsa: mt7530: fix kernel bug in mdiobus_free() when
 unbinding
Patch-mainline: v5.17-rc4
Git-commit: 9ffe3d09e32da45bb5a29cf2e80ec8d7534010c5
References: git-fixes

Nobody in this driver calls mdiobus_unregister(), which is necessary if
mdiobus_register() completes successfully. So if the devres callbacks
that free the mdiobus get invoked (this is the case when unbinding the
driver), mdiobus_free() will BUG if the mdiobus is still registered,
which it is.

My speculation is that this is due to the fact that prior to commit
ac3a68d56651 ("net: phy: don't abuse devres in devm_mdiobus_register()")
from June 2020, _devm_mdiobus_free() used to call mdiobus_unregister().
But at the time that the mt7530 support was introduced in May 2021, the
API was already changed. It's therefore likely that the blamed patch was
developed on an older tree, and incorrectly adapted to net-next. This
makes the Fixes: tag correct.

Fix the problem by using the devres variant of mdiobus_register.

Fixes: ba751e28d442 ("net: dsa: mt7530: add interrupt support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/dsa/mt7530.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 19b90d614ad7..cf58ef6e84f8 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -2007,7 +2007,7 @@ mt7530_setup_mdio(struct mt7530_priv *priv)
 	if (priv->irq)
 		mt7530_setup_mdio_irq(priv);
 
-	ret = mdiobus_register(bus);
+	ret = devm_mdiobus_register(dev, bus);
 	if (ret) {
 		dev_err(dev, "failed to register MDIO bus: %d\n", ret);
 		if (priv->irq)
-- 
2.16.4