[PATCH 4.9 150/329] batman-adv: Ignore invalid batadv_v_gw during netlink send

[Greg Kroah-Hartman]

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

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

From: Sven Eckelmann <sven.eckelmann@xxxxxxxxxxxx>

[ Upstream commit 011c935fceae5252619ef730baa610c655281dda ]

The function batadv_v_gw_dump stops the processing loop when
batadv_v_gw_dump_entry returns a non-0 return code. This should only
happen when the buffer is full. Otherwise, an empty message may be
returned by batadv_gw_dump. This empty message will then stop the netlink
dumping of gateway entries. At worst, not a single entry is returned to
userspace even when plenty of possible gateways exist.

Fixes: b71bb6f924fe ("batman-adv: add B.A.T.M.A.N. V bat_gw_dump implementations")
Signed-off-by: Sven Eckelmann <sven.eckelmann@xxxxxxxxxxxx>
Signed-off-by: Simon Wunderlich <sw@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/batman-adv/bat_v.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/batman-adv/bat_v.c
+++ b/net/batman-adv/bat_v.c
@@ -920,7 +920,7 @@ static int batadv_v_gw_dump_entry(struct
 	struct batadv_neigh_ifinfo *router_ifinfo = NULL;
 	struct batadv_neigh_node *router;
 	struct batadv_gw_node *curr_gw;
-	int ret = -EINVAL;
+	int ret = 0;
 	void *hdr;
 
 	router = batadv_orig_router_get(gw_node->orig_node, BATADV_IF_DEFAULT);