[ofa-general] Incorrect max_sge reported in mthca device query

[Tom Tucker]

Roland:

I think the max_sge reported by mthca_query_device is off by one. If you
try to create a QP with the reported max, it fails with -EINVAL. I think
the reason is that the mthca_alloc_wqe_buf function reserves a slot for
a "bind request" and this pushes the WQE size over the 496B limit when
the user requests the max (30) when allocating the QP.

Please let me know if I'm confused about what max_sge really means.

Thanks,
Tom