RE: [PATCH v5] net/iavf: revert fix VLAN insertion

["Zhang, Qi Z" <qi.z.zhang@intel.com>]

> -----Original Message-----
> From: Zhou, YidingX <yidingx.zhou@intel.com>
> Sent: Monday, November 14, 2022 12:31 AM
> To: dev@dpdk.org; Yang, Qiming <qiming.yang@intel.com>
> Cc: Zhang, Qi Z <qi.z.zhang@intel.com>; ktraynor@redhat.com; Zhou,
> YidingX <yidingx.zhou@intel.com>; stable@dpdk.org
> Subject: [PATCH v5] net/iavf: revert fix VLAN insertion
> 
> The vector Tx path does not support VLAN insertion via the L2TAG2 field, but
> the scalar path supports. The earlier commit was to force to select scalar
> path as soon as kernel driver requests to use L2TAG2. That logic is incorrect.
> Because other case like VLAN offloading not required but scalar path selected
> would have a significant performance drop.
> 
> Therefore the following commit was reverted accordingly.
> 
> commit 0d58caa7d6d1 ("net/iavf: fix VLAN insertion")
> 
> After reverting this commit, the AVX512 Tx path would insert the VLAN tag
> into the wrong location(inner of QinQ) when the kernel driver requested
> L2TAG2. This is inconsistent with the behavior of PF(outer of QinQ).
> 
> It is currently known that ice kernel drivers newer than 1.8.9 will request the
> use of L2TAG2. User can set parameter '--force-max-simd-bitwidth' to
> 64/128/256 to avoid this issue.
> 
> Fixes: 0d58caa7d6d1 ("net/iavf: fix VLAN insertion")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Yiding Zhou <yidingx.zhou@intel.com>

Acked-by: Qi Zhang <qi.z.zhang@intel.com>

Applied to dpdk-next-net-intel.

Thanks
Qi