[openib-general] RFC: detecting duplicate MAD requests

[Michael S. Tsirkin]

Quoting r. Sean Hefty <mshefty at ichips.intel.com>:
> Subject: Re: RFC: detecting duplicate MAD requests
> 
> Michael S. Tsirkin wrote:
> >>We're kind of left with the same issue of trying to determine if a received
> >>MAD will generate a response.
> > 
> > 
> > How do you mean? We have IsDS=1 flag for dual-sided, don't we? Dual-sided
> > transfer always has a response, doesn't it?

I mean, the flag in the application that says that the transfer is dual-sided.
The spec seems to imply that user can figure *from the method* that IsDS=1, so I
assume users will have this logic:

"2)
Begin the initial transfer by starting the send operation at the point labelled
Send. The method or other indication should be interpreted on
the other side as initiating a double-sided transfer, causing the receive
context to set IsDS=1."


So why does the MAD layer care whether a received MAD will generate a resonse?
A request arrives - we pass it up. Now the ACK for the direction switch arrives
- we pass it up too, application should be waiting for it, it should take the
window and pass the response back to us.

-- 
MST