Re: [PATCH net-next v12 2/4] net: dsa: tag_ks8995: Add the KS8995 tag handling

Hi Linus

On 11.9.2026 11:09, Linus Walleij wrote:

The KS8995 100Mbit switch can do proper DSA per-port tagging
with the proper set-up. This adds the code to handle ingress
and egress KS8995 tags.

The tagger is used by the KSZ8995XA support added later in this
series.

The tag is a modified 0x8100 ethertype tag where a bit in the
last nybble is set for each target port.

Nordic nit: nybble -> nibble

Always insert a distinct outer switch tag. User ports remove this
field on egress, so reusing an existing 802.1Q header would consume
the sender VLAN tag instead of preserving it.

Push any hardware-accelerated VLAN tag into the packet first. This
keeps the switch tag at offset 12 while retaining 802.1Q, 802.1ad and
stacked VLAN headers as inner payload, and avoids relying on a valid
SKB MAC header in direct transmit paths.

Rate-limit receive untagging errors so repeated failures cannot flood
the kernel log.

Assisted-by: LLM
Signed-off-by: Linus Walleij <linusw@kernel.org>
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[...]

Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>

Thanks,
Nicolai