Re: [dpdk-dev] [PATCH] net/mlx5: fix order of items in neon scatter func

[Dekel Peled <dekelp@mellanox.com>]

PSB, thanks.

> -----Original Message-----
> From: Shahaf Shuler
> Sent: Sunday, May 26, 2019 9:49 PM
> To: Dekel Peled <dekelp@mellanox.com>; Yongseok Koh
> <yskoh@mellanox.com>
> Cc: dev@dpdk.org; stable@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH] net/mlx5: fix order of items in neon scatter
> func
> 
> Wednesday, May 15, 2019 1:08 PM, Dekel Peled:
> > Subject: [dpdk-dev] [PATCH] net/mlx5: fix order of items in neon
> > scatter func
> >
> > Previous patch added handling of metadata for multi-segment packet.
> > Function txq_scatter_v in file mlx5_rxtx_vec_neon.h was updated
> > incorrectly, items were inserted into WQE in wrong order.
> >
> > This patch fixes the issue, inserting items into WQE correctly.
> >
> > Fixes: 7f4019d370f6 ("net/mlx5: fix Tx metadata for multi-segment
> > packet")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Dekel Peled <dekelp@mellanox.com>
> > ---
> >  drivers/net/mlx5/mlx5_rxtx_vec_neon.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/mlx5/mlx5_rxtx_vec_neon.h
> > b/drivers/net/mlx5/mlx5_rxtx_vec_neon.h
> > index 38e915c..b1e0e8f 100644
> > --- a/drivers/net/mlx5/mlx5_rxtx_vec_neon.h
> > +++ b/drivers/net/mlx5/mlx5_rxtx_vec_neon.h
> > @@ -171,7 +171,7 @@
> >  		/* Fill ESEG in the header. */
> >  		vst1q_u32((void *)(t_wqe + 1),
> >  			  ((uint32x4_t){ 0,
> > -					 cs_flags << 16 |
> > rte_cpu_to_be_16(len),
> > +					 rte_cpu_to_be_16(len) << 16 |
> > cs_flags,
> 
> It was probably not introduced by the previous patch, but since you touch
> this area:
> Why do you set the mss (len)? This function handles only non-TSO packets.

mss is set to 0 in txq_burst_v, which sends single segment packets.
This change is in txq_scatter_v which sends multi-segmented packets.

> 
> >  					 metadata, 0 }));
> >  		txq->wqe_ci = wqe_ci;
> >  	}
> > --
> > 1.8.3.1