Re: [dpdk-dev] [PATCH v2] examples/qos_meter: fix unchecked return value

["Dumitrescu, Cristian" <cristian.dumitrescu@intel.com>]

> -----Original Message-----
> From: Jastrzebski, MichalX K
> Sent: Thursday, April 21, 2016 12:48 PM
> To: Dumitrescu, Cristian <cristian.dumitrescu@intel.com>; Zhang, Roy Fan
> <roy.fan.zhang@intel.com>; Singh, Jasvinder <jasvinder.singh@intel.com>
> Cc: dev@dpdk.org; Mrozowicz, SlawomirX
> <slawomirx.mrozowicz@intel.com>
> Subject: [PATCH v2] examples/qos_meter: fix unchecked return value
> 
> From: Slawomir Mrozowicz <slawomirx.mrozowicz@intel.com>
> 
> Fix issue reported by Coverity.
> 
> Coverity ID 30693: Unchecked return value
> check_return: Calling rte_meter_srtcm_config without checking return
> value.
> 
> Fixes: e6541fdec8b2 ("meter: initial import")
> 
> Signed-off-by: Slawomir Mrozowicz <slawomirx.mrozowicz@intel.com>
> ---
>  examples/qos_meter/main.c | 15 ++++++++++-----
>  examples/qos_meter/main.h |  2 +-
>  2 files changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/examples/qos_meter/main.c b/examples/qos_meter/main.c
> index b968b00..16b0b87 100644
> --- a/examples/qos_meter/main.c
> +++ b/examples/qos_meter/main.c
> @@ -133,14 +133,17 @@ struct rte_meter_trtcm_params
> app_trtcm_params[] = {
> 
>  FLOW_METER app_flows[APP_FLOWS_MAX];
> 
> -static void
> +static int
>  app_configure_flow_table(void)
>  {
>  	uint32_t i, j;
> +	int ret = 0;
> 
> -	for (i = 0, j = 0; i < APP_FLOWS_MAX; i ++, j = (j + 1) %
> RTE_DIM(PARAMS)){
> -		FUNC_CONFIG(&app_flows[i], &PARAMS[j]);
> -	}
> +	for (i = 0, j = 0; i < APP_FLOWS_MAX;
> +			i ++, j = (j + 1) % RTE_DIM(PARAMS))
> +		ret |= FUNC_CONFIG(&app_flows[i], &PARAMS[j]);
> +
> +	return ret;
>  }


You should probably return of the first error rather than carry on. How would you know which is the flow that produced the configuration error?

for (i = 0, j = 0; i < APP_FLOWS_MAX; i ++, j = (j + 1) % RTE_DIM(PARAMS)){
	ret = FUNC_CONFIG(&app_flows[i], &PARAMS[j]);
	if (ret)
		return;
}

> 
>  static inline void
> @@ -381,7 +384,9 @@ main(int argc, char **argv)
>  	rte_eth_promiscuous_enable(port_tx);
> 
>  	/* App configuration */
> -	app_configure_flow_table();
> +	ret = app_configure_flow_table();
> +	if (ret < 0)
> +		rte_exit(EXIT_FAILURE, "Invalid configure flow table\n");
> 
>  	/* Launch per-lcore init on every lcore */
>  	rte_eal_mp_remote_launch(main_loop, NULL, CALL_MASTER);
> diff --git a/examples/qos_meter/main.h b/examples/qos_meter/main.h
> index 530bf69..54867dc 100644
> --- a/examples/qos_meter/main.h
> +++ b/examples/qos_meter/main.h
> @@ -51,7 +51,7 @@ enum policer_action
> policer_table[e_RTE_METER_COLORS][e_RTE_METER_COLORS] =
>  #if APP_MODE == APP_MODE_FWD
> 
>  #define FUNC_METER(a,b,c,d) color, flow_id=flow_id, pkt_len=pkt_len,
> time=time
> -#define FUNC_CONFIG(a,b)
> +#define FUNC_CONFIG(a, b) 0
>  #define PARAMS	app_srtcm_params
>  #define FLOW_METER int
> 
> --
> 1.9.1