> From: linux-rdma-owner@xxxxxxxxxxxxxxx [mailto:linux-rdma- > owner@xxxxxxxxxxxxxxx] On Behalf Of Roland Dreier > Sent: Wednesday, September 20, 2017 7:39 PM > To: linux-rdma@xxxxxxxxxxxxxxx > Subject: Is ib_mtu iboe_get_mtu() slightly off? > > We have: > > static inline enum ib_mtu iboe_get_mtu(int mtu) { > /* > * reduce IB headers from effective IBoE MTU. 28 stands for > * atomic header which is the biggest possible header after BTH > */ > mtu = mtu - IB_GRH_BYTES - IB_BTH_BYTES - 28; > ... > > 28 bytes is the size of the AtomicETH header. But couldn't we have a packet > with both AtomicETH and XRCETH (4 more bytes)? XRCETH + AtomicETH is possible. Additionally I guess 4 bytes of ICRC is missing too in calculation. ��.n��������+%������w��{.n�����{���fk��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
