Re: [PATCH net-next] net: ibm: emac: Reserve VLAN header in MJS limit

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Paolo Abeni <pabeni@xxxxxxxxxx>:

On Tue, 26 May 2026 13:22:47 -0700 you wrote:
> The IBM EMAC programs its Maximum Jumbo Size (MJS) drop
> threshold from ndev->mtu directly. The hardware sizes the threshold
> against the L2 frame minus the ethernet header, but does not
> discount the 802.1Q tag, so a frame carrying a VLAN tag and a full
> 1500-byte payload exceeds MJS by exactly 4 bytes and is dropped.
> 
> This is normally hidden because JPSM (and therefore the MJS check)
> only engages when the MTU is raised above ETH_DATA_LEN.  With the
> qca8k DSA tagger the conduit MTU is bumped by QCA_HDR_LEN to 1502
> during dsa_conduit_setup(), which is enough to enable JPSM and
> expose the off-by-VLAN-tag in the limit.
> 
> [...]

Here is the summary with links:
  - [net-next] net: ibm: emac: Reserve VLAN header in MJS limit
    https://git.kernel.org/netdev/net-next/c/0906c117f81c

You are awesome, thank you!
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