Re: [PATCH net-next v3 1/4] net: hsr: generate supervision frame without HSR/PRP tag

On Tue, Feb 09, 2021 at 07:02:10PM -0600, George McCollister wrote:

For a switch to offload insertion of HSR/PRP tags, frames must not be
sent to the CPU facing switch port with a tag. Generate supervision frames
(eth type ETH_P_PRP) without HSR v1 (ETH_P_HSR)/PRP tag and rely on
create_tagged_frame which inserts it later. This will allow skipping the
tag insertion for all outgoing frames in the future which is required for
HSR v1/PRP tag insertions to be offloaded.

HSR v0 supervision frames always contain tag information so insertion of
the tag can't be offloaded. IEC 62439-3 Ed.2.0 (HSR v1) specifically
notes that this was changed since v0 to allow offloading.

Signed-off-by: George McCollister <george.mccollister@gmail.com>
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Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Tested-by: Vladimir Oltean <olteanv@gmail.com>