Re: [dpdk-dev] [PATCH] net/mlx5: fix count query when flow has not counters

[Yongseok Koh <yskoh@mellanox.com>]

> On Jul 25, 2018, at 1:46 AM, Nelio Laranjeiro <nelio.laranjeiro@6wind.com> wrote:
> 
> Querying a counters on a flow without counter is ending with a
> segmentation fault.
> 
> Fixes: 60bd8c9747e8 ("net/mlx5: add count flow action")
> 
> Signed-off-by: Nelio Laranjeiro <nelio.laranjeiro@6wind.com>
> ---
> drivers/net/mlx5/mlx5_flow.c | 56 ++++++++++++++++++++----------------
> 1 file changed, 32 insertions(+), 24 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
> index 6fa4e30ae..efaa8b4fb 100644
> --- a/drivers/net/mlx5/mlx5_flow.c
> +++ b/drivers/net/mlx5/mlx5_flow.c
> @@ -3192,32 +3192,40 @@ mlx5_flow_query_count(struct rte_flow *flow __rte_unused,
> 		      struct rte_flow_error *error)
> {
> #ifdef HAVE_IBV_DEVICE_COUNTERS_SET_SUPPORT
> -	struct rte_flow_query_count *qc = data;
> -	uint64_t counters[2] = {0, 0};
> -	struct ibv_query_counter_set_attr query_cs_attr = {
> -		.cs = flow->counter->cs,
> -		.query_flags = IBV_COUNTER_SET_FORCE_UPDATE,
> -	};
> -	struct ibv_counter_set_data query_out = {
> -		.out = counters,
> -		.outlen = 2 * sizeof(uint64_t),
> -	};
> -	int err = mlx5_glue->query_counter_set(&query_cs_attr, &query_out);
> +	if (flow->modifier & MLX5_FLOW_MOD_COUNT) {

Instead of adding extra indentation, how about returning error immediately if
the flow doesn't have a counter? That looks more natural. But even if you insist
this way, I'm also okay. Please let Shahaf know if you will submit v2.

Acked-by: Yongseok Koh <yskoh@mellanox.com>
 
Thanks

> +		struct rte_flow_query_count *qc = data;
> +		uint64_t counters[2] = {0, 0};
> +		struct ibv_query_counter_set_attr query_cs_attr = {
> +			.cs = flow->counter->cs,
> +			.query_flags = IBV_COUNTER_SET_FORCE_UPDATE,
> +		};
> +		struct ibv_counter_set_data query_out = {
> +			.out = counters,
> +			.outlen = 2 * sizeof(uint64_t),
> +		};
> +		int err = mlx5_glue->query_counter_set(&query_cs_attr,
> +						       &query_out);
> 
> -	if (err)
> -		return rte_flow_error_set(error, err,
> -					  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> -					  NULL,
> -					  "cannot read counter");
> -	qc->hits_set = 1;
> -	qc->bytes_set = 1;
> -	qc->hits = counters[0] - flow->counter->hits;
> -	qc->bytes = counters[1] - flow->counter->bytes;
> -	if (qc->reset) {
> -		flow->counter->hits = counters[0];
> -		flow->counter->bytes = counters[1];
> +		if (err)
> +			return rte_flow_error_set
> +				(error, err,
> +				 RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> +				 NULL,
> +				 "cannot read counter");
> +		qc->hits_set = 1;
> +		qc->bytes_set = 1;
> +		qc->hits = counters[0] - flow->counter->hits;
> +		qc->bytes = counters[1] - flow->counter->bytes;
> +		if (qc->reset) {
> +			flow->counter->hits = counters[0];
> +			flow->counter->bytes = counters[1];
> +		}
> +		return 0;
> 	}
> -	return 0;
> +	return rte_flow_error_set(error, ENOTSUP,
> +				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> +				  NULL,
> +				  "flow does not have counter");
> #endif
> 	return rte_flow_error_set(error, ENOTSUP,
> 				  RTE_FLOW_ERROR_TYPE_UNSPECIFIED,
> -- 
> 2.18.0
>