[PATCH 4.17 245/324] sfp: ensure we clean up properly on bus registration failure

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>

[ Upstream commit f20a4c46b984331a509528fa2b84125c617ef98b ]

We fail to correctly clean up after a bus registration failure, which
can lead to an incorrect assumption about the registration state of
the upstream or sfp cage.

Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/phy/sfp-bus.c |   31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

--- a/drivers/net/phy/sfp-bus.c
+++ b/drivers/net/phy/sfp-bus.c
@@ -436,6 +436,13 @@ void sfp_upstream_stop(struct sfp_bus *b
 }
 EXPORT_SYMBOL_GPL(sfp_upstream_stop);
 
+static void sfp_upstream_clear(struct sfp_bus *bus)
+{
+	bus->upstream_ops = NULL;
+	bus->upstream = NULL;
+	bus->netdev = NULL;
+}
+
 /**
  * sfp_register_upstream() - Register the neighbouring device
  * @fwnode: firmware node for the SFP bus
@@ -462,8 +469,11 @@ struct sfp_bus *sfp_register_upstream(st
 		bus->upstream = upstream;
 		bus->netdev = ndev;
 
-		if (bus->sfp)
+		if (bus->sfp) {
 			ret = sfp_register_bus(bus);
+			if (ret)
+				sfp_upstream_clear(bus);
+		}
 		rtnl_unlock();
 	}
 
@@ -488,8 +498,7 @@ void sfp_unregister_upstream(struct sfp_
 	rtnl_lock();
 	if (bus->sfp)
 		sfp_unregister_bus(bus);
-	bus->upstream = NULL;
-	bus->netdev = NULL;
+	sfp_upstream_clear(bus);
 	rtnl_unlock();
 
 	sfp_bus_put(bus);
@@ -561,6 +570,13 @@ void sfp_module_remove(struct sfp_bus *b
 }
 EXPORT_SYMBOL_GPL(sfp_module_remove);
 
+static void sfp_socket_clear(struct sfp_bus *bus)
+{
+	bus->sfp_dev = NULL;
+	bus->sfp = NULL;
+	bus->socket_ops = NULL;
+}
+
 struct sfp_bus *sfp_register_socket(struct device *dev, struct sfp *sfp,
 				    const struct sfp_socket_ops *ops)
 {
@@ -573,8 +589,11 @@ struct sfp_bus *sfp_register_socket(stru
 		bus->sfp = sfp;
 		bus->socket_ops = ops;
 
-		if (bus->netdev)
+		if (bus->netdev) {
 			ret = sfp_register_bus(bus);
+			if (ret)
+				sfp_socket_clear(bus);
+		}
 		rtnl_unlock();
 	}
 
@@ -592,9 +611,7 @@ void sfp_unregister_socket(struct sfp_bu
 	rtnl_lock();
 	if (bus->netdev)
 		sfp_unregister_bus(bus);
-	bus->sfp_dev = NULL;
-	bus->sfp = NULL;
-	bus->socket_ops = NULL;
+	sfp_socket_clear(bus);
 	rtnl_unlock();
 
 	sfp_bus_put(bus);