net/mlx5: Fix auto group size calculation

Once all the large flow groups (defined by the user when the flow table
is created - max_num_groups) were created, then all the following new
flow groups will have only one flow table entry, even though the flow table
has place to larger groups.
Fix the condition to prefer large flow group.

Fixes: f0d22d1 ("net/mlx5_core: Introduce flow steering autogrouped flow table")
Signed-off-by: Maor Gottlieb <[email protected]>
Signed-off-by: Saeed Mahameed <[email protected]>

Author: Maor Gottlieb

drivers/net/ethernet/mellanox/mlx5/core/fs_core.c

@@ -579,7 +579,7 @@ static void del_sw_flow_group(struct fs_node *node)
 
 	rhashtable_destroy(&fg->ftes_hash);
 	ida_destroy(&fg->fte_allocator);
-	if (ft->autogroup.active)
+	if (ft->autogroup.active && fg->max_ftes == ft->autogroup.group_size)
 		ft->autogroup.num_groups--;
 	err = rhltable_remove(&ft->fgs_hash,
 			      &fg->hash,
@@ -1126,6 +1126,8 @@ mlx5_create_auto_grouped_flow_table(struct mlx5_flow_namespace *ns,
 
 	ft->autogroup.active = true;
 	ft->autogroup.required_groups = max_num_groups;
+	/* We save place for flow groups in addition to max types */
+	ft->autogroup.group_size = ft->max_fte / (max_num_groups + 1);
 
 	return ft;
 }
@@ -1328,8 +1330,7 @@ static struct mlx5_flow_group *alloc_auto_flow_group(struct mlx5_flow_table  *ft
 		return ERR_PTR(-ENOENT);
 
 	if (ft->autogroup.num_groups < ft->autogroup.required_groups)
-		/* We save place for flow groups in addition to max types */
-		group_size = ft->max_fte / (ft->autogroup.required_groups + 1);
+		group_size = ft->autogroup.group_size;
 
 	/*  ft->max_fte == ft->autogroup.max_types */
 	if (group_size == 0)
@@ -1356,7 +1357,8 @@ static struct mlx5_flow_group *alloc_auto_flow_group(struct mlx5_flow_table  *ft
 	if (IS_ERR(fg))
 		goto out;
 
-	ft->autogroup.num_groups++;
+	if (group_size == ft->autogroup.group_size)
+		ft->autogroup.num_groups++;
 
 out:
 	return fg;

drivers/net/ethernet/mellanox/mlx5/core/fs_core.h

@@ -162,6 +162,7 @@ struct mlx5_flow_table {
 	struct {
 		bool			active;
 		unsigned int		required_groups;
+		unsigned int		group_size;
 		unsigned int		num_groups;
 	} autogroup;
 	/* Protect fwd_rules */