b25cf61a33
Traditionally, the MTU in "datagram" transport mode was restricted to 2044. That is no longer the case, relax that. In fact, choose a very large maximum and don't differenciate between "connected" mode (they now both use now 65520). This is only the limitation of the connection profile. Whether setting such large MTUs actually works must be determined when activating the profile. Initscripts "ifup-ib" from rdma-core package originally had a limit of 2044. This was raised to 4092 in rh#1186498. It is suggested to raise it further in bug rh#1647541. In general, kernel often does not allow setting large MTUs. And even if it allows it, it may not work because it also requires the entire network to be configured accordingly. But that means, it is generally not helpful to limit the MTU in the connection profile too strictly. Just allow large MTUs, we need to see at activation time whether the configuration works. Note also that all other setting types don't validate the range for MTU at all. Related: https://bugzilla.redhat.com/show_bug.cgi?id=1186498 Related: https://bugzilla.redhat.com/show_bug.cgi?id=1593334 (rdma-core: raise limit from 2044 to 4092 in ifup-ib) Related: https://bugzilla.redhat.com/show_bug.cgi?id=1647541 (rdma-core: raise limit beyond 4092 in ifup-ib) Related: https://bugzilla.redhat.com/show_bug.cgi?id=1532638#c4 (rdma-core: MTU related discussion) Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1534869 (NetworkManager bug about this topic, but with lots of unrelated discussion. See in particular #c16) Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1653494