[patch net] mlxsw: spectrum_router: Don't log an error on missing neighbor

[patch net] mlxsw: spectrum_router: Don't log an error on missing neighbor

[Jiri Pirko]

From: Yuval Mintz <yuvalm@mellanox.com>

Driver periodically samples all neighbors configured in device
in order to update the kernel regarding their state. When finding
an entry configured in HW that doesn't show in neigh_lookup()
driver logs an error message.
This introduces a race when removing multiple neighbors -
it's possible that a given entry would still be configured in HW
as its removal is still being processed but is already removed
from the kernel's neighbor tables.

Simply remove the error message and gracefully accept such events.

Fixes: c723c735fa6b ("mlxsw: spectrum_router: Periodically update the kernel's neigh table")
Fixes: 60f040ca11b9 ("mlxsw: spectrum_router: Periodically dump active IPv6 neighbours")
Signed-off-by: Yuval Mintz <yuvalm@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 6c0391c13fe0..7042c855a5d6 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -1942,11 +1942,8 @@ static void mlxsw_sp_router_neigh_ent_ipv4_process(struct mlxsw_sp *mlxsw_sp,
 	dipn = htonl(dip);
 	dev = mlxsw_sp->router->rifs[rif]->dev;
 	n = neigh_lookup(&arp_tbl, &dipn, dev);
-	if (!n) {
-		netdev_err(dev, "Failed to find matching neighbour for IP=%pI4h\n",
-			   &dip);
+	if (!n)
 		return;
-	}
 
 	netdev_dbg(dev, "Updating neighbour with IP=%pI4h\n", &dip);
 	neigh_event_send(n, NULL);
@@ -1973,11 +1970,8 @@ static void mlxsw_sp_router_neigh_ent_ipv6_process(struct mlxsw_sp *mlxsw_sp,
 
 	dev = mlxsw_sp->router->rifs[rif]->dev;
 	n = neigh_lookup(&nd_tbl, &dip, dev);
-	if (!n) {
-		netdev_err(dev, "Failed to find matching neighbour for IP=%pI6c\n",
-			   &dip);
+	if (!n)
 		return;
-	}
 
 	netdev_dbg(dev, "Updating neighbour with IP=%pI6c\n", &dip);
 	neigh_event_send(n, NULL);
-- 
2.14.3

Re: [patch net] mlxsw: spectrum_router: Don't log an error on missing neighbor

[David Miller]

From: Jiri Pirko <jiri@resnulli.us>
Date: Wed, 24 Jan 2018 10:02:09 +0100

> From: Yuval Mintz <yuvalm@mellanox.com>
> 
> Driver periodically samples all neighbors configured in device
> in order to update the kernel regarding their state. When finding
> an entry configured in HW that doesn't show in neigh_lookup()
> driver logs an error message.
> This introduces a race when removing multiple neighbors -
> it's possible that a given entry would still be configured in HW
> as its removal is still being processed but is already removed
> from the kernel's neighbor tables.
> 
> Simply remove the error message and gracefully accept such events.
> 
> Fixes: c723c735fa6b ("mlxsw: spectrum_router: Periodically update the kernel's neigh table")
> Fixes: 60f040ca11b9 ("mlxsw: spectrum_router: Periodically dump active IPv6 neighbours")
> Signed-off-by: Yuval Mintz <yuvalm@mellanox.com>
> Reviewed-by: Ido Schimmel <idosch@mellanox.com>
> Signed-off-by: Jiri Pirko <jiri@mellanox.com>

Applied and queued up for -stable, thanks.