[dpdk-dev] [PATCH] eal: simplify RTE_PMD_DEBUG_TRACE

[Ferruh Yigit]

On 12/14/2018 9:20 PM, Jeff Shaw wrote:
> On Fri, Dec 14, 2018 at 12:50:55PM -0800, Stephen Hemminger wrote:
>> Use rte_log directly, eliminating no longer used rte_pmd_dev_trace
>> function. This removes variable length array which is problem on
>> Windows and other compilers not doing C99.
>>
>> Also, drop unused RTE_PROC_PRIMARY macros.
>>
>> Reported-by: Jeff Shaw <jeffrey.b.shaw at intel.com>
>> Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
>> ---
>>  lib/librte_eal/common/include/rte_dev.h | 43 ++-----------------------
>>  1 file changed, 3 insertions(+), 40 deletions(-)
>>
>> diff --git a/lib/librte_eal/common/include/rte_dev.h b/lib/librte_eal/common/include/rte_dev.h
>> index a9724dc9181c..e496da440028 100644
>> --- a/lib/librte_eal/common/include/rte_dev.h
>> +++ b/lib/librte_eal/common/include/rte_dev.h
>> @@ -43,54 +43,17 @@ typedef void (*rte_dev_event_cb_fn)(const char *device_name,
>>  					enum rte_dev_event_type event,
>>  					void *cb_arg);
>>  
>> -__attribute__((format(printf, 2, 0)))
>> -static inline void
>> -rte_pmd_debug_trace(const char *func_name, const char *fmt, ...)
>> -{
>> -	va_list ap;
>> -
>> -	va_start(ap, fmt);
>> -
>> -	{
>> -		char buffer[vsnprintf(NULL, 0, fmt, ap) + 1];
>> -
>> -		va_end(ap);
>> -
>> -		va_start(ap, fmt);
>> -		vsnprintf(buffer, sizeof(buffer), fmt, ap);
>> -		va_end(ap);
>> -
>> -		rte_log(RTE_LOG_ERR, RTE_LOGTYPE_PMD, "%s: %s",
>> -			func_name, buffer);
>> -	}
>> -}
>> -
> 
> Will this break applications that try to use this function? Because it is not
> a documented function, is there no guarantee it will be present?
> 
>>  /*
>>   * Enable RTE_PMD_DEBUG_TRACE() when at least one component relying on the
>>   * RTE_*_RET() macros defined below is compiled in debug mode.
>>   */
>>  #if defined(RTE_LIBRTE_EVENTDEV_DEBUG)
>> -#define RTE_PMD_DEBUG_TRACE(...) \
>> -	rte_pmd_debug_trace(__func__, __VA_ARGS__)
>> +#define RTE_PMD_DEBUG_TRACE(fmt, args...) \
>> +	rte_log(RTE_LOG_ERR, RTE_LOGTYPE_PMD, "%s():" fmt, __func__, ## args)
> 
> Actually, MSVC does not support named variable arguments either. I think this
> will work instead:
> 
>   #define RTE_PMD_DEBUG_TRACE(fmt, ...) \
>           rte_log(RTE_LOG_ERR, RTE_LOGTYPE_PMD, "%s():" fmt, __func__, __VA_ARGS__)
> 
> The previous behavior was "%s: ..." not "%s():". I'm not sure if you meant to
> change how the messages are displayed. I don't care either way, but maybe
> users of the function would prefer the same format.
> 

+1 to remove "rte_pmd_debug_trace()" option, but I guess a new version is
required, to switch to '__VA_ARGS__' and perhaps to keep the format same, %s vs
%s().

Who can send a new version? Jeff?