Re: [dpdk-dev] [dpdk-stable] [PATCH] net/mlx5: fix ConnectX-4LX Tx burst routines set

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 1/9/2020 9:03 AM, Slava Ovsiienko wrote:
>> -----Original Message-----
>> From: Ferruh Yigit <ferruh.yigit@intel.com>
>> Sent: Wednesday, January 8, 2020 17:55
>> To: Slava Ovsiienko <viacheslavo@mellanox.com>; dev@dpdk.org
>> Cc: Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
>> <rasland@mellanox.com>; Ori Kam <orika@mellanox.com>; stable@dpdk.org;
>> Thomas Monjalon <thomas@monjalon.net>
>> Subject: Re: [dpdk-stable] [PATCH] net/mlx5: fix ConnectX-4LX Tx burst
>> routines set
>>
>> On 1/8/2020 3:50 PM, Slava Ovsiienko wrote:
>>> Hi, Ferruh
>>>
>>>> -----Original Message-----
>>>> From: Ferruh Yigit <ferruh.yigit@intel.com>
>>>> Sent: Wednesday, January 8, 2020 16:55
>>>> To: Slava Ovsiienko <viacheslavo@mellanox.com>; dev@dpdk.org
>>>> Cc: Matan Azrad <matan@mellanox.com>; Raslan Darawsheh
>>>> <rasland@mellanox.com>; Ori Kam <orika@mellanox.com>;
>>>> stable@dpdk.org; Thomas Monjalon <thomas@monjalon.net>
>>>> Subject: Re: [dpdk-stable] [PATCH] net/mlx5: fix ConnectX-4LX Tx
>>>> burst routines set
>>>>
>>>> On 1/8/2020 2:53 PM, Ferruh Yigit wrote:
>>>>> On 12/20/2019 10:48 AM, Viacheslav Ovsiienko wrote:
>>>>>> The tx_burst routine supporting multi-segment packets with legacy
>>>>>> MPW and without inline was missed, and there was no valid selection
>>>>>> for these options, patch adds the missing routine.
>>>>>>
>>>>>> Fixes: 82e75f8323bf ("net/mlx5: fix legacy multi-packet Tx
>>>>>> descriptors")
>>>>>> Cc: stable@dpdk.org
>>>>>>
>>>>>> Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
>>
>> <...>
>>
>>>>>> @@ -5297,6 +5305,7 @@ enum mlx5_txcmp_code {
>>>>>>  		DRV_LOG(DEBUG, "port %u has no selected Tx function"
>>>>>>  			       " for requested offloads %04X",
>>>>>>  				dev->data->port_id, olx);
>>>>>> +		assert(false);
>>
>> <...>
>>
>>>
>>>>
>>>>>
>>>>> I think we should avoid PMDs calling the assert unconditionally,
>>>>> specially in a code that debug level log is printed.
>>>>>
>>>>>>  		return NULL;
>>>>>>  	}
>>>>>>  	DRV_LOG(DEBUG, "port %u has selected Tx function"
>>>
>>> Yes, I agree. We just do not have the check for the result returned by
>>> mlx5_select_tx_function(). I think we should check against NULL and
>>> report an error.  "assert" is a temporary solution till this upgrade
>>> (in debug mode we have a lot of messages and break on assert helps to
>>> locate the problem quickly, reporting error will do the same).
>>>
>>
>> Can it be possible to drop the patch from mlx tree and prepare a new version
>> without 'assert'?
> The selection routine error handling is rather generic and is not merely related to ConnectX-4LX.
> I propose to prepare the dedicated patch, what do you  think?
> 

My concern is with the assert, the error handling can be another patch, but can
we have this change without an assert? Or perhaps a RTE_ASSERT() which is for debug.