[PATCH net] mlxsw: spectrum_mr: Fix list iteration in error path

[PATCH net] mlxsw: spectrum_mr: Fix list iteration in error path

[Ido Schimmel]

From: Ido Schimmel <idosch@mellanox.com>

list_for_each_entry_from_reverse() iterates backwards over the list from
the current position, but in the error path we should start from the
previous position.

Fix this by using list_for_each_entry_continue_reverse() instead.

This suppresses the following error from coccinelle:

drivers/net/ethernet/mellanox/mlxsw//spectrum_mr.c:655:34-38: ERROR:
invalid reference to the index variable of the iterator on line 636

Fixes: c011ec1bbfd6 ("mlxsw: spectrum: Add the multicast routing offloading logic")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c
index 54275624718b..336e5ecc68f8 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c
@@ -637,12 +637,12 @@ static int mlxsw_sp_mr_vif_resolve(struct mlxsw_sp_mr_table *mr_table,
 	return 0;
 
 err_erif_unresolve:
-	list_for_each_entry_from_reverse(erve, &mr_vif->route_evif_list,
-					 vif_node)
+	list_for_each_entry_continue_reverse(erve, &mr_vif->route_evif_list,
+					     vif_node)
 		mlxsw_sp_mr_route_evif_unresolve(mr_table, erve);
 err_irif_unresolve:
-	list_for_each_entry_from_reverse(irve, &mr_vif->route_ivif_list,
-					 vif_node)
+	list_for_each_entry_continue_reverse(irve, &mr_vif->route_ivif_list,
+					     vif_node)
 		mlxsw_sp_mr_route_ivif_unresolve(mr_table, irve);
 	mr_vif->rif = NULL;
 	return err;
-- 
2.24.1

Re: [PATCH net] mlxsw: spectrum_mr: Fix list iteration in error path

[David Miller]

From: Ido Schimmel <idosch@idosch.org>
Date: Thu, 26 Mar 2020 16:17:33 +0200

> From: Ido Schimmel <idosch@mellanox.com>
> 
> list_for_each_entry_from_reverse() iterates backwards over the list from
> the current position, but in the error path we should start from the
> previous position.
> 
> Fix this by using list_for_each_entry_continue_reverse() instead.
> 
> This suppresses the following error from coccinelle:
> 
> drivers/net/ethernet/mellanox/mlxsw//spectrum_mr.c:655:34-38: ERROR:
> invalid reference to the index variable of the iterator on line 636
> 
> Fixes: c011ec1bbfd6 ("mlxsw: spectrum: Add the multicast routing offloading logic")
> Signed-off-by: Ido Schimmel <idosch@mellanox.com>
> Reviewed-by: Jiri Pirko <jiri@mellanox.com>

Applied and queued up for -stable, thanks.