Re: [dpdk-dev] [PATCH] net/mlx5: fix modify header action position

[Yongseok Koh <yskoh@mellanox.com>]

On Sun, Apr 14, 2019 at 08:19:57PM +0000, Ori Kam wrote:
> According to RTE flow the action order should be the order that the
> actions were given.
> In the case of modify actions the position of the action was always
> last.
> 
> This commit solves this issue by saving the position of the first modify
> action, and then adds to this position the pointer to the modify action.
> 
> Fixes: 4bb14c83df95 ("net/mlx5: support modify header using Direct Verbs")
> Cc: dekelp@mellanox.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Ori Kam <orika@mellanox.com>
> ---
>  drivers/net/mlx5/mlx5_flow_dv.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
> index 3862b26..7b5eab7 100644
> --- a/drivers/net/mlx5/mlx5_flow_dv.c
> +++ b/drivers/net/mlx5/mlx5_flow_dv.c
> @@ -3235,6 +3235,7 @@ struct field_modify_info modify_tcp[] = {
>  	};
>  	union flow_dv_attr flow_attr = { .attr = 0 };
>  	struct mlx5_flow_dv_tag_resource tag_resource;
> +	uint32_t modify_action_position = UINT32_MAX;

How about modify_action_idx and setting negative value as invalid? I don't force
it but it is just your choice.

	int modify_action_idx = -1;

>  	if (priority == MLX5_FLOW_PRIO_RSVD)
>  		priority = priv->config.flow_prio - 1;
> @@ -3419,6 +3420,8 @@ struct field_modify_info modify_tcp[] = {
>  					RTE_FLOW_ACTION_TYPE_SET_MAC_SRC ?
>  					MLX5_FLOW_ACTION_SET_MAC_SRC :
>  					MLX5_FLOW_ACTION_SET_MAC_DST;
> +			if (modify_action_position == UINT32_MAX)
> +				modify_action_position = actions_n++;

Even though this does right thing, I hope it to be neater. Same lines are
repeating before 'break', so you can move it just out of this switch-case.
For example,

	for(..) {
		switch(..) {
		case ..
		default:
			break;
		}
		/* Check if a modify action is firstly seen. */
		if (modify_action_idx < 0 &&
		    (action_flags & MLX5_FLOW_MODIFY_HDR_ACTIONS))
			modify_action_idx = actions_n++;
	}

thanks,
Yongseok

>  			break;
>  		case RTE_FLOW_ACTION_TYPE_SET_IPV4_SRC:
>  		case RTE_FLOW_ACTION_TYPE_SET_IPV4_DST:
> @@ -3429,6 +3432,8 @@ struct field_modify_info modify_tcp[] = {
>  					RTE_FLOW_ACTION_TYPE_SET_IPV4_SRC ?
>  					MLX5_FLOW_ACTION_SET_IPV4_SRC :
>  					MLX5_FLOW_ACTION_SET_IPV4_DST;
> +			if (modify_action_position == UINT32_MAX)
> +				modify_action_position = actions_n++;
>  			break;
>  		case RTE_FLOW_ACTION_TYPE_SET_IPV6_SRC:
>  		case RTE_FLOW_ACTION_TYPE_SET_IPV6_DST:
> @@ -3439,6 +3444,8 @@ struct field_modify_info modify_tcp[] = {
>  					RTE_FLOW_ACTION_TYPE_SET_IPV6_SRC ?
>  					MLX5_FLOW_ACTION_SET_IPV6_SRC :
>  					MLX5_FLOW_ACTION_SET_IPV6_DST;
> +			if (modify_action_position == UINT32_MAX)
> +				modify_action_position = actions_n++;
>  			break;
>  		case RTE_FLOW_ACTION_TYPE_SET_TP_SRC:
>  		case RTE_FLOW_ACTION_TYPE_SET_TP_DST:
> @@ -3450,6 +3457,8 @@ struct field_modify_info modify_tcp[] = {
>  					RTE_FLOW_ACTION_TYPE_SET_TP_SRC ?
>  					MLX5_FLOW_ACTION_SET_TP_SRC :
>  					MLX5_FLOW_ACTION_SET_TP_DST;
> +			if (modify_action_position == UINT32_MAX)
> +				modify_action_position = actions_n++;
>  			break;
>  		case RTE_FLOW_ACTION_TYPE_DEC_TTL:
>  			if (flow_dv_convert_action_modify_dec_ttl(&res, items,
> @@ -3457,6 +3466,8 @@ struct field_modify_info modify_tcp[] = {
>  								  error))
>  				return -rte_errno;
>  			action_flags |= MLX5_FLOW_ACTION_DEC_TTL;
> +			if (modify_action_position == UINT32_MAX)
> +				modify_action_position = actions_n++;
>  			break;
>  		case RTE_FLOW_ACTION_TYPE_SET_TTL:
>  			if (flow_dv_convert_action_modify_ttl(&res, actions,
> @@ -3464,6 +3475,8 @@ struct field_modify_info modify_tcp[] = {
>  							     error))
>  				return -rte_errno;
>  			action_flags |= MLX5_FLOW_ACTION_SET_TTL;
> +			if (modify_action_position == UINT32_MAX)
> +				modify_action_position = actions_n++;
>  			break;
>  		case RTE_FLOW_ACTION_TYPE_END:
>  			actions_end = true;
> @@ -3474,7 +3487,7 @@ struct field_modify_info modify_tcp[] = {
>  								 dev_flow,
>  								 error))
>  					return -rte_errno;
> -				dev_flow->dv.actions[actions_n++] =
> +				dev_flow->dv.actions[modify_action_position] =
>  					dev_flow->dv.modify_hdr->verbs_action;
>  			}
>  			break;
> -- 
> 1.8.3.1
>