[dpdk-dev] [PATCH v4 15/23] rte_ethdev.h: align sign and scope of temp var

[Andy Green]

On 05/17/2018 09:54 PM, Bruce Richardson wrote:
> On Mon, May 14, 2018 at 01:10:43PM +0800, Andy Green wrote:
>> Signed-off-by: Andy Green <andy at warmcat.com>
>> ---
>>   lib/librte_ethdev/rte_ethdev.h |   25 +++++++++++++++----------
>>   1 file changed, 15 insertions(+), 10 deletions(-)
>>
> 
> While I dislike the changes below, since I believe it's always more
> readable to declare variables at first use, if the changes are needed to
> remove compiler errors in apps, then they need to be fixed.
> 
> Patch needs a suitable commit log explaining the changes or giving the
> error message.

It has this in the last push (which overlapped with your comment)... I 
seem to have missed the error about declarations after code not being 
allowed in C90, but I guess that part being an issue is not controversial.

> 
>> diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
>> index 49c2ebbd5..2cb5fe3be 100644
>> --- a/lib/librte_ethdev/rte_ethdev.h
>> +++ b/lib/librte_ethdev/rte_ethdev.h
>> @@ -3801,6 +3801,7 @@ 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);
>> @@ -3811,18 +3812,22 @@ 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);
>> +		}
>>   	}
>>   #endif
> 
> Rather than increasing the level of indentation needed with the extra
> braces, it's probably best to separate variable definition and assignment
> as you did in the first change above.

IIRC my thinking was I had a choice to repeat the conditional 
compilation stuff around the declaration (because it's in an #ifdef), 
(void)cb; to dodge the unused var warning, or add a basic block for it 
to scope to.  The last one didn't seem so bad.

-Andy

> /Bruce
>