[PATCH AUTOSEL for 4.9 016/156] net/mlx5: Fix create autogroup prev initializer

[alexander . levin]

From: Paul Blakey <paulb@xxxxxxxxxxxx>

[ Upstream commit af36370569eb37420e1e78a2e60c277b781fcd00 ]

The autogroups list is a list of non overlapping group boundaries
sorted by their start index. If the autogroups list wasn't empty
and an empty group slot was found at the start of the list,
the new group was added to the end of the list instead of the
beginning, as the prev initializer was incorrect.
When this was repeated, it caused multiple groups to have
overlapping boundaries.

Fixed that by correctly initializing the prev pointer to the
start of the list.

Fixes: eccec8da3b4e ('net/mlx5: Keep autogroups list ordered')
Signed-off-by: Paul Blakey <paulb@xxxxxxxxxxxx>
Reviewed-by: Mark Bloch <markb@xxxxxxxxxxxx>
Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx5/core/fs_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
index 4de3c28b0547..331a6ca4856d 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
@@ -1015,7 +1015,7 @@ static struct mlx5_flow_group *create_autogroup(struct mlx5_flow_table *ft,
 						u32 *match_criteria)
 {
 	int inlen = MLX5_ST_SZ_BYTES(create_flow_group_in);
-	struct list_head *prev = ft->node.children.prev;
+	struct list_head *prev = &ft->node.children;
 	unsigned int candidate_index = 0;
 	struct mlx5_flow_group *fg;
 	void *match_criteria_addr;
-- 
2.11.0