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

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

> -----Original Message-----
> From: Mrozowicz, SlawomirX
> Sent: Thursday, May 12, 2016 8:06 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: 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.

Yes, you're right, my bad, sorry.

> 
> >> >>
> >> >>  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