In commit a07f5f50 "[IPV4] fib_trie: style
cleanup", the changes to check_leaf() and fn_trie_lookup() were wrong - where
fn_trie_lookup() would previously return a negative error value from
check_leaf(), it now returns 0.
 
Now fn_trie_lookup() doesn't appear to care about plen, so we can revert
check_leaf() to returning the error value.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Tested-by: NWilliam Boughton <bill@boughton.de>
Acked-by: NStephen Heminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>