netdev - [patch net v2 2/2] mlxsw: spectrum_router: Correctly dump neighbour activity

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Date:   Fri, 11 Nov 2016 16:34:26 +0100
From:   Jiri Pirko <jiri@...nulli.us>
To:     netdev@...r.kernel.org
Cc:     davem@...emloft.net, yotamg@...lanox.com, arkadis@...lanox.com,
        idosch@...lanox.com, eladr@...lanox.com, nogahf@...lanox.com,
        ogerlitz@...lanox.com
Subject: [patch net v2 2/2] mlxsw: spectrum_router: Correctly dump neighbour activity

From: Arkadi Sharshevsky <arkadis@...lanox.com>

The device's neighbour table is periodically dumped in order to update
the kernel about active neighbours. A single dump session may span
multiple queries, until the response carries less records than requested
or when a record (can contain up to four neighbour entries) is not full.
Current code stops the session when the number of returned records is
zero, which can result in infinite loop in case of high packet rate.

Fix this by stopping the session according to the above logic.

Fixes: c723c735fa6b ("mlxsw: spectrum_router: Periodically update the kernel's neigh table")
Signed-off-by: Arkadi Sharshevsky <arkadis@...lanox.com>
Signed-off-by: Ido Schimmel <idosch@...lanox.com>
Signed-off-by: Jiri Pirko <jiri@...lanox.com>
---
v1->v2:
- remove an extra space
- fix the description
---
 .../net/ethernet/mellanox/mlxsw/spectrum_router.c  | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 040737e..cbeeddd 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -800,6 +800,26 @@ static void mlxsw_sp_router_neigh_rec_process(struct mlxsw_sp *mlxsw_sp,
 	}
 }
 
+static bool mlxsw_sp_router_rauhtd_is_full(char *rauhtd_pl)
+{
+	u8 num_rec, last_rec_index, num_entries;
+
+	num_rec = mlxsw_reg_rauhtd_num_rec_get(rauhtd_pl);
+	last_rec_index = num_rec - 1;
+
+	if (num_rec < MLXSW_REG_RAUHTD_REC_MAX_NUM)
+		return false;
+	if (mlxsw_reg_rauhtd_rec_type_get(rauhtd_pl, last_rec_index) ==
+	    MLXSW_REG_RAUHTD_TYPE_IPV6)
+		return true;
+
+	num_entries = mlxsw_reg_rauhtd_ipv4_rec_num_entries_get(rauhtd_pl,
+								last_rec_index);
+	if (++num_entries == MLXSW_REG_RAUHTD_IPV4_ENT_PER_REC)
+		return true;
+	return false;
+}
+
 static int mlxsw_sp_router_neighs_update_rauhtd(struct mlxsw_sp *mlxsw_sp)
 {
 	char *rauhtd_pl;
@@ -826,7 +846,7 @@ static int mlxsw_sp_router_neighs_update_rauhtd(struct mlxsw_sp *mlxsw_sp)
 		for (i = 0; i < num_rec; i++)
 			mlxsw_sp_router_neigh_rec_process(mlxsw_sp, rauhtd_pl,
 							  i);
-	} while (num_rec);
+	} while (mlxsw_sp_router_rauhtd_is_full(rauhtd_pl));
 	rtnl_unlock();
 
 	kfree(rauhtd_pl);
-- 
2.7.4