[openib-general] QP from userspace used in kernel

[Dan Bar Dov]

This is what we are doing in ISER (creating the QP in kernel as the
connect action of a socket provider that is accessed by userspace).

Dan

On 12/8/05, Caitlin Bestler <caitlinb at broadcom.com> wrote:
> openib-general-bounces at openib.org wrote:
> > Hi,
> >
> > What are the reasons that a qp allocated in user-space can't
> > be passed and used by a kernel module?
> > What are the steps needed to make a userspace-allocated qp usable by
> > a kernel module?
> >
> >
>
> You would need to construct an environment such that the
> device-specific verbs module, which assumes it is executing
> in the user space where the QP was created, would never notice
> the difference.
>
> The device-specific verbs will typically have created shared
> memory resources that are accessible by both the RDMA device
> and from the creating user memory map. These resources may
> include pointers that assume the original memory map. The
> exact methods of remembering the locations of these resources
> will vary by device, so the chance of coming up with a scheme
> that works without explicit support of all device vendors is
> very low. The chances of convincing all device vendors to add
> a new option to support this model is similarly low unless you
> can make a very compelling case as to why this is necessary.
>
> Having the in-kernel proxy create the QP and do operations
> for the end-user is a very adequate work around.
>
> For complex cleanup purposes the kernel could simply assume
> the identity of the failed process, but that would only be
> required if the standard cleanup was somehow not adequate.
>
> _______________________________________________
> openib-general mailing list
> openib-general at openib.org
> http://openib.org/mailman/listinfo/openib-general
>
> To unsubscribe, please visit http://openib.org/mailman/listinfo/openib-general
>