Subject: [net 01/12] net/mlx5: Fix flow table chaining

From: Saeed Mahameed <[email-masked]>
Date: Tue, 27 Jul 2021 16:20:39 -0700

From: Maor Gottlieb <[email-masked]>

Fix a bug when flow table is created in priority that already
has other flow tables as shown in the below diagram.
If the new flow table (FT-B) has the lowest level in the priority,
we need to connect the flow tables from the previous priority (p0)
to this new table. In addition when this flow table is destroyed
(FT-B), we need to connect the flow tables from the previous
priority (p0) to the next level flow table (FT-C) in the same
priority of the destroyed table (if exists).

                       ---------
                       |root_ns|
                       ---------
                            |
            --------------------------------
            |               |              |
       ----------      ----------      ---------
       |p(prio)-x|     |   p-y  |      |   p-n |
       ----------      ----------      ---------
            |               |
     ----------------  ------------------
     |ns(e.g bypass)|  |ns(e.g. kernel) |
     ----------------  ------------------
            |            |           |
	-------	       ------       ----
        |  p0 |        | p1 |       |p2|
        -------        ------       ----
           |             |    \
        --------       ------- ------
        | FT-A |       |FT-B | |FT-C|
        --------       ------- ------

Fixes: f90edfd279f3 ("net/mlx5_core: Connect flow tables")
Signed-off-by: Maor Gottlieb <[email-masked]>
Reviewed-by: Mark Bloch <[email-masked]>
Signed-off-by: Saeed Mahameed <[email-masked]>
---
 drivers/net/ethernet/mellanox/mlx5/core/fs_core.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
index d7bf0a3e4a52..c0697e1b7118 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
@@ -1024,17 +1024,19 @@ static int connect_fwd_rules(struct mlx5_core_dev *dev,
 static int connect_flow_table(struct mlx5_core_dev *dev, struct mlx5_flow_table *ft,
 			      struct fs_prio *prio)
 {
-	struct mlx5_flow_table *next_ft;
+	struct mlx5_flow_table *next_ft, *first_ft;
 	int err = 0;
 
 	/* Connect_prev_fts and update_root_ft_create are mutually exclusive */
 
-	if (list_empty(&prio->node.children)) {
+	first_ft = list_first_entry_or_null(&prio->node.children,
+					    struct mlx5_flow_table, node.list);
+	if (!first_ft || first_ft->level > ft->level) {
 		err = connect_prev_fts(dev, ft, prio);
 		if (err)
 			return err;
 
-		next_ft = find_next_chained_ft(prio);
+		next_ft = first_ft ? first_ft : find_next_chained_ft(prio);
 		err = connect_fwd_rules(dev, ft, next_ft);
 		if (err)
 			return err;
@@ -2120,7 +2122,7 @@ static int disconnect_flow_table(struct mlx5_flow_table *ft)
 				node.list) == ft))
 		return 0;
 
-	next_ft = find_next_chained_ft(prio);
+	next_ft = find_next_ft(ft);
 	err = connect_fwd_rules(dev, next_ft, ft);
 	if (err)
 		return err;
-- 
2.31.1