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

Roland Dreier
2009-11-11T23:02:06Z

> | 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.