Re: [dpdk-dev] [PATCH v3] examples/qos_meter: fix unchecked return value

["Mrozowicz, SlawomirX" <slawomirx.mrozowicz@intel.com>]

>-----Original Message-----
>From: Dumitrescu, Cristian
>Sent: Wednesday, May 11, 2016 7:57 PM
>To: Mrozowicz, SlawomirX <slawomirx.mrozowicz@intel.com>
>Cc: dev@dpdk.org; Singh, Jasvinder <jasvinder.singh@intel.com>
>Subject: RE: [PATCH v3] examples/qos_meter: fix unchecked return value
>
>
>
>> -----Original Message-----
>> From: Mrozowicz, SlawomirX
>> Sent: Wednesday, May 11, 2016 10:15 AM
>> To: Dumitrescu, Cristian <cristian.dumitrescu@intel.com>
>> Cc: dev@dpdk.org; Singh, Jasvinder <jasvinder.singh@intel.com>
>> Subject: RE: [PATCH v3] examples/qos_meter: fix unchecked return value
>>
>>
>>
>> >-----Original Message-----
>> >From: Dumitrescu, Cristian
>> >Sent: Tuesday, May 10, 2016 7:42 PM
>> >To: Mrozowicz, SlawomirX <slawomirx.mrozowicz@intel.com>
>> >Cc: dev@dpdk.org; Singh, Jasvinder <jasvinder.singh@intel.com>
>> >Subject: RE: [PATCH v3] examples/qos_meter: fix unchecked return
>> >value
>> >
>> >
>> >
>> >> -----Original Message-----
>> >> From: Mrozowicz, SlawomirX
>> >> Sent: Monday, May 9, 2016 9:38 AM
>> >> To: Dumitrescu, Cristian <cristian.dumitrescu@intel.com>
>> >> Cc: dev@dpdk.org; Singh, Jasvinder <jasvinder.singh@intel.com>;
>> >> Mrozowicz, SlawomirX <slawomirx.mrozowicz@intel.com>
>> >> Subject: [PATCH v3] examples/qos_meter: fix unchecked return value
>> >>
>> >> 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..7c69606 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 && ret == 0;
>> >> +			i ++, j = (j + 1) % RTE_DIM(PARAMS))
>> >> +		ret = FUNC_CONFIG(&app_flows[i], &PARAMS[j]);
>> >> +
>> >> +	return ret;
>> >>  }
>> >
>> >This is only returns the configuration status for the last flow and
>> >leaves undetected an error for any other flow. Why not check the
>> >status for each flow and return an error on first occurrence?
>> >For (...){ret = FUNC_CONFIG(...); if (ret) return ret;}
>> >
>>
>> This code check status of the function FUNC_CONFIG for each flow and
>> return an error on first occurrence. Rest of functions FUNC_CONFIG are
>> not called. See terminate condition of the loop.
>>
>
>Where is the status of FUNC_CONFIG checked exactly? I cannot see any check
>in your code. I can only see returning the status code for the last call of this
>function in the for loop. I was expecting a check such as: if (ret) return ret.
>

Look at the loop terminate conditions:
i < APP_FLOWS_MAX && ret == 0
Program terminate the loop if the ret variable is differ then zero.
It means that program terminate if the last status of FUNC_CONFIG is an error.

>> >>
>> >>  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