[dpdk-dev] [PATCH 1/7] ethdev: remove unused flag from header

[Ferruh Yigit]

On 12/1/2017 2:17 PM, Vlad Zolotarov wrote:
> 
> 
> On 11/30/2017 09:29 PM, Ferruh Yigit wrote:
>> remove RTE_ETHDEV_HAS_LRO_SUPPORT flag from header.
>>
>> Flag seems added with the patch that adds LRO support, and intention
>> looks like giving a pointer to application that library supports LRO.
> 
> Exactly. Removing this flag may make the existing application "think" that LRO
> is not supported.
> Why do you want to remove it to begin with?

I agree that this is a little controversial, and I don't have a strong opinion
about it, I thought twice before sending or not sending the patch :)

This flag can be useful for the applications that use different versions of the
DPDK library (with the ones does and doesn't support LRO), so that application
can be more portable.
I would understand a dynamic approach, which would be useful for distributed
applications that you don't know and can't control what version of the DPDK
library used.
But here to benefit from this flag you need to compile your application against
DPDK library, and if you are compiling it you already know if your DPDK supports
LRO or not. And this is not something keeps changing platform to platform etc,
after a specific release LRO is always supported.

And this is the only capability support flag in the ethdev, there are many new
features introduced in each release but they are not advertised by a capability
flag. Only having LRO flag can be confusing.

_Perhaps_ DPDK should have a way to expose the supported features, and a dynamic
runtime way can be better option than compile time macros, but it should be
generic nothing specific to LRO support.

> 
>>
>> Fixes: 8eecb3295aed ("ixgbe: add LRO support")
>> Cc: vladz at cloudius-systems.com
>>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit at intel.com>
>> ---
>>  lib/librte_ether/rte_ethdev.h | 3 ---
>>  1 file changed, 3 deletions(-)
>>
>> diff --git a/lib/librte_ether/rte_ethdev.h b/lib/librte_ether/rte_ethdev.h
>> index 341c2d624..e620c3706 100644
>> --- a/lib/librte_ether/rte_ethdev.h
>> +++ b/lib/librte_ether/rte_ethdev.h
>> @@ -172,9 +172,6 @@ extern "C" {
>>  
>>  #include <stdint.h>
>>  
>> -/* Use this macro to check if LRO API is supported */
>> -#define RTE_ETHDEV_HAS_LRO_SUPPORT
>> -
>>  #include <rte_log.h>
>>  #include <rte_interrupts.h>
>>  #include <rte_dev.h>
>