[PATCH 4.14 67/99] batman-adv: Avoid spurious warnings from bat_v neigh_cmp implementation

From: Greg Kroah-Hartman
Date: Thu Mar 19 2020 - 09:17:37 EST


From: Sven Eckelmann <sven.eckelmann@xxxxxxxxxxxx>

commit 6a4bc44b012cbc29c9d824be2c7ab9eac8ee6b6f upstream.

The neighbor compare API implementation for B.A.T.M.A.N. V checks whether
the neigh_ifinfo for this neighbor on a specific interface exists. A
warning is printed when it isn't found.

But it is not called inside a lock which would prevent that this
information is lost right before batadv_neigh_ifinfo_get. It must therefore
be expected that batadv_v_neigh_(cmp|is_sob) might not be able to get the
requested neigh_ifinfo.

A WARN_ON for such a situation seems not to be appropriate because this
will only flood the kernel logs. The warnings must therefore be removed.

Signed-off-by: Sven Eckelmann <sven.eckelmann@xxxxxxxxxxxx>
Signed-off-by: Simon Wunderlich <sw@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/batman-adv/bat_v.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

--- a/net/batman-adv/bat_v.c
+++ b/net/batman-adv/bat_v.c
@@ -19,7 +19,6 @@
#include "main.h"

#include <linux/atomic.h>
-#include <linux/bug.h>
#include <linux/cache.h>
#include <linux/errno.h>
#include <linux/if_ether.h>
@@ -623,11 +622,11 @@ static int batadv_v_neigh_cmp(struct bat
int ret = 0;

ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
- if (WARN_ON(!ifinfo1))
+ if (!ifinfo1)
goto err_ifinfo1;

ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
- if (WARN_ON(!ifinfo2))
+ if (!ifinfo2)
goto err_ifinfo2;

ret = ifinfo1->bat_v.throughput - ifinfo2->bat_v.throughput;
@@ -649,11 +648,11 @@ static bool batadv_v_neigh_is_sob(struct
bool ret = false;

ifinfo1 = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
- if (WARN_ON(!ifinfo1))
+ if (!ifinfo1)
goto err_ifinfo1;

ifinfo2 = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
- if (WARN_ON(!ifinfo2))
+ if (!ifinfo2)
goto err_ifinfo2;

threshold = ifinfo1->bat_v.throughput / 4;