[PATCH v4] net: stmmac: Prevent DSA tags from breaking COE

[Paolo Abeni]

On Tue, 2024-01-09 at 15:42 +0100, Romain Gantois wrote:
> Some DSA tagging protocols change the EtherType field in the MAC header
> e.g.  DSA_TAG_PROTO_(DSA/EDSA/BRCM/MTK/RTL4C_A/SJA1105). On TX these tagged
> frames are ignored by the checksum offload engine and IP header checker of
> some stmmac cores.
> 
> On RX, the stmmac driver wrongly assumes that checksums have been computed
> for these tagged packets, and sets CHECKSUM_UNNECESSARY.
> 
> Add an additional check in the stmmac TX and RX hotpaths so that COE is
> deactivated for packets with ethertypes that will not trigger the COE and
> IP header checks.
> 
> Fixes: 6b2c6e4a938f ("net: stmmac: propagate feature flags to vlan")
> Cc:  <stable at vger.kernel.org>
> Reported-by: Richard Tresidder <rtresidd at electromag.com.au>
> Link: https://lore.kernel.org/netdev/e5c6c75f-2dfa-4e50-a1fb-6bf4cdb617c2@electromag.com.au/
> Reported-by: Romain Gantois <romain.gantois at bootlin.com>
> Link: https://lore.kernel.org/netdev/c57283ed-6b9b-b0e6-ee12-5655c1c54495@bootlin.com/
> Reviewed-by: Vladimir Oltean <vladimir.oltean at nxp.com>
> Signed-off-by: Romain Gantois <romain.gantois at bootlin.com>

Unfortunately, you dropped the target tree tag ('net') from the
subject, and did not allow our CI to trigger properly.

Since we can't merge this patch ATM ('net' is currently frozen since we
merge back the net-next PR), I think it's better if you resubmit with a
proper tag. You can retain all Vladimir Rb tag.

Cheers,

Paolo