[PATCH AUTOSEL 4.19 057/146] net: phy: phylink: ensure the carrier is off when starting phylink

Sasha Levin
2018-10-31T23:50:09Z

From: Antoine Tenart <antoine.tenart@bootlin.com>

[ Upstream commit aeeb2e8fdefdd5d257a1446351c70cb3df540199 ]

Phylink made an assumption about the carrier state being down when
calling phylink_start(). If this assumption isn't satisfied, the
internal phylink state could misbehave and a net device could end up not
being functional.

This patch fixes this by explicitly calling netif_carrier_off() in
phylink_start().

Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/phy/phylink.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 7abca86c3aa9..70f3f90c2ed6 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -907,6 +907,9 @@ void phylink_start(struct phylink *pl)
phylink_an_mode_str(pl->link_an_mode),
phy_modes(pl->link_config.interface));

+ /* Always set the carrier off */
+ netif_carrier_off(pl->netdev);
+
/* Apply the link configuration to the MAC when starting. This allows
* a fixed-link to start with the correct parameters, and also
* ensures that we set the appropriate advertisement for Serdes links.
--
2.17.1