[PATCH 5.7 046/265] of: of_mdio: Correct loop scanning logic

Sasha Levin
2020-06-29T22:00:59Z

From: Florian Fainelli <f.fainelli@gmail.com>

[ Upstream commit 5a8d7f126c97d04d893f5e5be2b286437a0d01b0 ]

Commit 209c65b61d94 ("drivers/of/of_mdio.c:fix of_mdiobus_register()")
introduced a break of the loop on the premise that a successful
registration should exit the loop. The premise is correct but not to
code, because rc && rc != -ENODEV is just a special error condition,
that means we would exit the loop even with rc == -ENODEV which is
absolutely not correct since this is the error code to indicate to the
MDIO bus layer that scanning should continue.

Fix this by explicitly checking for rc = 0 as the only valid condition
to break out of the loop.

Fixes: 209c65b61d94 ("drivers/of/of_mdio.c:fix of_mdiobus_register()")
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/of/of_mdio.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/of/of_mdio.c b/drivers/of/of_mdio.c
index 9f982c0627a0d..95a3bb2e5eabf 100644
--- a/drivers/of/of_mdio.c
+++ b/drivers/of/of_mdio.c
@@ -303,10 +303,15 @@ int of_mdiobus_register(struct mii_bus *mdio, struct device_node *np)
child, addr);

if (of_mdiobus_child_is_phy(child)) {
+ /* -ENODEV is the return code that PHYLIB has
+ * standardized on to indicate that bus
+ * scanning should continue.
+ */
rc = of_mdiobus_register_phy(mdio, child, addr);
- if (rc && rc != -ENODEV)
+ if (!rc)
+ break;
+ if (rc != -ENODEV)
goto unregister;
- break;
}
}
}
--
2.25.1