[openib-general] Question about QP access flags (struct ib_qp_attr.qp_access_flags)

[Ralph Campbell]

Any comments from OpenIB developers about the following?

    Ralph> When ib_modify_qp() is called with the IB_QP_ACCESS_FLAGS
    Ralph> set in the mask, what values should be used in struct
    Ralph> ib_qp_attr.qp_access_flags?  The IB spec. seems to indicate
    Ralph> that RDMA and atomic operations are all enabled or disabled
    Ralph> as a group but all I see in ib_verbs.h is the enum
    Ralph> ib_access_flags which is used for memory region access.
    Ralph> These are more fine grained than the IB spec. implies for
    Ralph> QPs.  So I can see qp_access_flags being either a boolean
    Ralph> or perhaps a new enum defined for the values for
    Ralph> qp_access_flags.

Roland> I think the IB spec is at best ambiguous as to whether RDMA
Roland> and atomics are enabled as a group or not.
Roland> The values are IB_ACCESS_REMOTE_ATOMIC, IB_ACCESS_REMOTE_WRITE,
Roland> and IB_ACCESS_REMOTE_READ or-ed together I think.
Roland>
Roland> You should probably ask on openib-general to find out what
Roland> the consensus is.  Sean Hefty is the guy who originally
Roland> defined this interface.

-- 
Ralph Campbell <ralphc at pathscale.com>