[dpdk-dev] [PATCH v6 8/8] rte_ethdev.h: align sign and scope of temp var

[Andy Green]

On 05/21/2018 09:30 PM, Bruce Richardson wrote:
> On Mon, May 21, 2018 at 10:01:33AM +0800, Andy Green wrote:
>> /projects/lagopus/src/dpdk/build/include/rte_ethdev.h:
>> In function 'rte_eth_rx_burst':
>> /projects/lagopus/src/dpdk/build/include/rte_ethdev.h:
>> 3836:18: warning: conversion to 'int16_t' {aka 'short
>> int'} from 'uint16_t' {aka 'short unsigned int'} may
>> change the sign of the result [-Wsign-conversion]
>>    int16_t nb_rx = (*dev->rx_pkt_burst)(dev->data->
>> rx_queues[queue_id],
>>                    ^
>> /projects/lagopus/src/dpdk/build/include/rte_ethdev.h:
>> 3844:50: warning: conversion to 'uint16_t' {aka 'short
>> unsigned int'} from 'int16_t' {aka 'short int'} may
>> change the sign of the result [-Wsign-conversion]
>>      nb_rx = cb->fn.rx(port_id, queue_id, rx_pkts, nb_rx,
>>                                                    ^~~~~
>> /projects/lagopus/src/dpdk/build/include/rte_ethdev.h:
>> 3844:12: warning: conversion to 'int16_t' {aka 'short
>> int'} from 'uint16_t' {aka 'short unsigned int'} may
>> change the sign of the result [-Wsign-conversion]
>>      nb_rx = cb->fn.rx(port_id, queue_id, rx_pkts, nb_rx,
>>              ^~
>> /projects/lagopus/src/dpdk/build/include/rte_ethdev.h:
>> 3851:9: warning: conversion to 'uint16_t' {aka 'short
>> unsigned int'} from 'int16_t' {aka 'short int'} may
>> change the sign of the result [-Wsign-conversion]
>>    return nb_rx;
>>           ^~~~~
>>
>> The second part of the patch is solved by its own basic
>> block because it is inside a preprocessor conditional.
>>
>> Bringing the declaration of the var to the top of the
>> function would require that also being given its own
>> preprocessor conditional, or a (void)var to avoid an
>> unused var warning.  The basic block is no worse than
>> those imho.
>>
>> Signed-off-by: Andy Green <andy at warmcat.com>
>> ---
>>   lib/librte_ethdev/rte_ethdev.h |   25 +++++++++++++++----------
>>   1 file changed, 15 insertions(+), 10 deletions(-)
>>
>> diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
>> index d52c1bed9..4d059a2a7 100644
>> --- a/lib/librte_ethdev/rte_ethdev.h
>> +++ b/lib/librte_ethdev/rte_ethdev.h
>> @@ -3823,6 +3823,7 @@ rte_eth_rx_burst(uint16_t port_id, uint16_t queue_id,
>>   		 struct rte_mbuf **rx_pkts, const uint16_t nb_pkts)
>>   {
>>   	struct rte_eth_dev *dev = &rte_eth_devices[port_id];
>> +	uint16_t nb_rx;
>>   
>>   #ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>   	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, 0);
>> @@ -3833,18 +3834,22 @@ rte_eth_rx_burst(uint16_t port_id, uint16_t queue_id,
>>   		return 0;
>>   	}
>>   #endif
>> -	int16_t nb_rx = (*dev->rx_pkt_burst)(dev->data->rx_queues[queue_id],
>> -			rx_pkts, nb_pkts);
>> +	nb_rx = (*dev->rx_pkt_burst)(dev->data->rx_queues[queue_id],
>> +				     rx_pkts, nb_pkts);
>>   
>>   #ifdef RTE_ETHDEV_RXTX_CALLBACKS
>> -	struct rte_eth_rxtx_callback *cb = dev->post_rx_burst_cbs[queue_id];
>> -
>> -	if (unlikely(cb != NULL)) {
>> -		do {
>> -			nb_rx = cb->fn.rx(port_id, queue_id, rx_pkts, nb_rx,
>> -						nb_pkts, cb->param);
>> -			cb = cb->next;
>> -		} while (cb != NULL);
>> +	{
>> +		struct rte_eth_rxtx_callback *cb =
>> +				dev->post_rx_burst_cbs[queue_id];
>> +
>> +		if (unlikely(cb != NULL)) {
>> +			do {
>> +				nb_rx = cb->fn.rx(port_id, queue_id,
>> +						  rx_pkts, nb_rx,
>> +						  nb_pkts, cb->param);
>> +				cb = cb->next;
>> +			} while (cb != NULL);
>> +		}
>>   	}
> 
> I think you can eliminate these extra brackets by moving the cb declaration
> inside the if body:
> 
> if (unlikely(dev->post_rx_burst_cbs[queue_id] != NULL)) {$
> 	struct rte_eth_rxtx_callback *cb =
> 			dev->post_rx_burst_cbs[queue_id];
> 	do {$
> 		nb_rx = cb->fn.rx(port_id, queue_id, rx_pkts, nb_rx,$
> 				nb_pkts, cb->param);$
> 		cb = cb->next;$
> 	} while (cb != NULL);$
> }

Okay... it repeats the expression but what the hey.  It's changed to 
that in the v7 just pushed.

-Andy

> /Bruce
>