[PATCH net] sfp: fix sfp-bus oops when removing socket/upstream

[Russell King]

When we remove a socket or upstream, and the other side isn't
registered, we dereference a NULL pointer, causing a kernel oops.
Fix this.

Signed-off-by: Russell King <rmk+ker...@armlinux.org.uk>
---
 drivers/net/phy/sfp-bus.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/sfp-bus.c b/drivers/net/phy/sfp-bus.c
index 8a1b1f4c1b7c..ab64a142b832 100644
--- a/drivers/net/phy/sfp-bus.c
+++ b/drivers/net/phy/sfp-bus.c
@@ -356,7 +356,8 @@ EXPORT_SYMBOL_GPL(sfp_register_upstream);
 void sfp_unregister_upstream(struct sfp_bus *bus)
 {
        rtnl_lock();
-       sfp_unregister_bus(bus);
+       if (bus->sfp)
+               sfp_unregister_bus(bus);
        bus->upstream = NULL;
        bus->netdev = NULL;
        rtnl_unlock();
@@ -459,7 +460,8 @@ EXPORT_SYMBOL_GPL(sfp_register_socket);
 void sfp_unregister_socket(struct sfp_bus *bus)
 {
        rtnl_lock();
-       sfp_unregister_bus(bus);
+       if (bus->netdev)
+               sfp_unregister_bus(bus);
        bus->sfp_dev = NULL;
        bus->sfp = NULL;
        bus->socket_ops = NULL;
-- 
2.7.4