From: Russell King <rmk+kernel@armlinux.org.uk>
Date: Wed, 20 Dec 2017 23:23:33 +0000
Subject: phylink: avoid attaching more than one PHY
Patch-mainline: v4.16-rc1
Git-commit: fe1c3ef201c1ae629df9ee60b64e7030f6e703fb
References: bsc#1119113 FATE#326472

Attaching more than one PHY to phylink is bad news, as we store a
pointer to the PHY in a single location. Error out if more than one
PHY is attempted to be attached.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/phy/phylink.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -726,6 +726,9 @@ int phylink_connect_phy(struct phylink *
 		     phy_interface_mode_is_8023z(pl->link_interface))))
 		return -EINVAL;
 
+	if (pl->phydev)
+		return -EBUSY;
+
 	/* Use PHY device/driver interface */
 	if (pl->link_interface == PHY_INTERFACE_MODE_NA) {
 		pl->link_interface = phy->interface;