Re: [PATCH] IB/core: export struct ib_port

Ralph Campbell
2009-11-11T23:22:50Z

On Wed, 2009-11-11 at 15:02 -0800, Roland Dreier wrote:
> > | Hmm, maybe we should just add a vls directory with sl0 ... sl15 or
> > | something like that in generic code? I don't see why this needs to be
> > | driver-specific code.
> >
> > No particular reason, it just didn't seem likely to be useful on other
> > HCA drivers. I can redo the patches that way, if people think it's
> > the right thing to do.
>
> To me it does seem like something generic. SLtoVL table is required of
> all CAs, so we might as well create it for all IB devices... as I see it
> the advantages of having it core code are:
>
> - no need to expose internals of sysfs code port structure to low level
> drivers (we could also avoid this layering violation by giving a
> generic way for low-level drivers to add port attributes)
> - IB-specified info is available for all IB devices with the same
> format etc. It may not be important for non-qlogic devices but there
> is some utility in SL mapping for debugging etc.
>
> the only disadvantage I see is that it adds the overhead of having those
> sysfs attributes for all systems with an RDMA devices, even if the
> qlogic driver is never loaded. But that overhead is pretty much just a
> small amount of extra code that will never be run and a few sysfs
> structures that will never be touched, so it just takes up a little bit
> of memory. For RDMA-using systems, I can't imagine it matters.
>
> - R.

While this is true for SLtoVL, we create other files which are
device specific under the port directory too.
It seems like we might need to introduce a callback into the driver to
create the port specific sysfs files.