Re: [PATCH V5 net-next 0/6] ethtool: add support to set/get tx copybreak buf size and rx buf len

Rx buf len is buffer length of each rx BD. Use ethtool -g command to get
it, and ethtool -G command to set it, examples are as follow:

1. set rx buf len to 4096
$ ethtool -G eth1 rx-buf-len 4096

2. get rx buf len
$ ethtool -g eth1
...
RX Buf Len:     4096

How does this interact with MTU? If i have an MTU of 1500, and i set
the rx-buf-len to 1000, can i expect all frames to the discarded?
Should the core return -EINVAL? Or do you think some hardware will
simply allocate two buffers and scatter/gather over them? Which
implies that drivers which cannot SG must check if the rx-buf-len is
less than the MTU and return -EINVAL?

     Andrew