[openib-general] Re: [PATCH 21 of 53] ipath - use phys_to_virt instead of bus_to_virt

Roland Dreier rdreier at cisco.com
Mon May 15 16:34:56 PDT 2006


    Grant> Aren't remote addresses handled differently than local
    Grant> ones?  ULP has to map local addresses.  We can't map remote
    Grant> ones (remote host maps it).  The ULP must know the
    Grant> difference and can tell the lower level driver which is
    Grant> which.

The problem is that RDMA requests have to be handled by the low-level
driver (or hardware) without any ULP involvement.  So every device has
to handle getting messages like "send me XXX bytes of data from
address YYY in the memory region corresponding to R_Key ZZZ."

 - R.



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