[PATCH 5.4 028/102] net/mlx5e: Fix free peer_flow when refcount is 0

Greg Kroah-Hartman
2020-01-24T09:34:42Z

From: Roi Dayan <roid@mellanox.com>

commit eb252c3a24fc5856fa62140c2f8269ddce6ce4e5 upstream.

It could be neigh update flow took a refcount on peer flow so
sometimes we cannot release peer flow even if parent flow is
being freed now.

Fixes: 5a7e5bcb663d ("net/mlx5e: Extend tc flow struct with reference counter")
Signed-off-by: Roi Dayan <roid@mellanox.com>
Reviewed-by: Eli Britstein <elibr@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -1615,8 +1615,11 @@ static void __mlx5e_tc_del_fdb_peer_flow

flow_flag_clear(flow, DUP);

- mlx5e_tc_del_fdb_flow(flow->peer_flow->priv, flow->peer_flow);
- kfree(flow->peer_flow);
+ if (refcount_dec_and_test(&flow->peer_flow->refcnt)) {
+ mlx5e_tc_del_fdb_flow(flow->peer_flow->priv, flow->peer_flow);
+ kfree(flow->peer_flow);
+ }
+
flow->peer_flow = NULL;
}