On Thu, Apr 28, 2016 at 09:53:52PM +0000, Hefty, Sean wrote: > > I see several litmus tests for what kinds of ports can be combined > > into a device (eg the 'protocol'): > > > > 1) Various cap tests are the same on every port. Particularly the > > iWarp special behaviours we are talking about here. > > 2) AHs are not port-specific, so the AH addressing format must be > > defined by the device. Thus IB and iWarp cannot be combined. > > 3) Verbs APM must work across ports. So eg rocee and IB cannot be > > combined since they use a different CM process. > > > > Multi-port really only exists to support APM, if APM doesn't work then > > drivers don't need to create multi-port devices. > > I don't know the details of the qlogic device, but it is entirely > possible that it allows different protocols to share resources (PDs, > CQs, IP addresses, etc.). I think we need to be careful dismissing > multi-protocol devices as silly, or restricting which protocols can > run over which port. This isn't dismissing them as silly, it is a pragmatic need in the core code that everything associated with a PD have a minimum standard of uniformity - and it is very clear that includes things like the iwarp special cases and the particular format of the AHs. For instance, even if a hardware device can run rocee and iwarp concurrently over a single port, today we absolutely must have different struct ib_devices for the same physical port to be able to plug that into the core stack. Fundamentally we have the wrong model for such hardware. When a PD is created it should set the 'protocol' and select the compatible member ports that belong to the PD. Cap tests and so forth should be done against the PD, not a port or a device. Fixing that is major surgery, and having cap tests to the port is not helping clarify the current situation. > Restricting all ports on a device to support all protocols is > different than restricting a device to supporting a single protocol, > and it affects more than APM. What else is there that is cross port in verbs? Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
