On Mon, 17 Oct 2016 12:49:54 -0400 (EDT), David Miller wrote:

From: Jakub Kicinski <redacted>
Date: Mon, 17 Oct 2016 17:20:06 +0100

quoted

Please correct me if I'm wrong but it seems like we are now limiting
_all_ ethernet drivers to ETH_DATA_LEN in net-next.  

No, because the driver can increase the netdev->max_mtu value as needed.

But since almost no driver is doing that, yet, right now in net-next
jumbo frames are not possible, no?  I thought the idea was the leave
the value at 0 so drivers can opt-in as needed but since setup_ether()
is initializing to 1500 now all ethernet driver get a default of
limiting to 1500.

IOW this patch made checks which were done only in eth_change_mtu()
mandatory for all drivers.