[PATCH 4.9 039/177] net/mlx5: Fix create autogroup prev initializer

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx5/core/fs_core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- 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_au
 						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;