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

[Slava Ovsiienko <viacheslavo@mellanox.com>]

> -----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?

With best regards, Slava