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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ansuel Smith <ansuelsmth@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.18 315/879] net: dsa: qca8k: correctly handle mdio read error
Date:   Tue,  7 Jun 2022 18:57:13 +0200
Message-Id: <20220607165011.991520585@linuxfoundation.org>
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From: Ansuel Smith <ansuelsmth@gmail.com>

[ Upstream commit 6cfc03b602200c5cbbd8d906fd905547814e83df ]

Restore original way to handle mdio read error by returning 0xffff.
This was wrongly changed when the internal_mdio_read was introduced,
now that both legacy and internal use the same function, make sure that
they behave the same way.

Fixes: ce062a0adbfe ("net: dsa: qca8k: fix kernel panic with legacy mdio mapping")
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/dsa/qca8k.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index d3ed0a7f8077..22b328bd7cd5 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -1287,7 +1287,12 @@ qca8k_internal_mdio_read(struct mii_bus *slave_bus, int phy, int regnum)
 	if (ret >= 0)
 		return ret;
 
-	return qca8k_mdio_read(priv, phy, regnum);
+	ret = qca8k_mdio_read(priv, phy, regnum);
+
+	if (ret < 0)
+		return 0xffff;
+
+	return ret;
 }
 
 static int
-- 
2.35.1