RE: [PATCH rdma-next] RDMA: Support more than 255 rdma ports

["Saleem, Shiraz" <shiraz.saleem@intel.com>]

> Subject: Re: [PATCH rdma-next] RDMA: Support more than 255 rdma ports
> 
> On Mon, Mar 01, 2021 at 09:04:20AM +0200, Leon Romanovsky wrote:
> > From: Mark Bloch <mbloch@nvidia.com>
> >
> > Current code uses many different types when dealing with a port of a
> > RDMA device: u8, unsigned int and u32. Switch to u32 to clean up the
> > logic.
> >
> > This allows us to make (at least) the core view consistent and use the
> > same type. Unfortunately not all places can be converted. Many uverbs
> > functions expect port to be u8 so keep those places in order not to break
> UAPIs.
> > HW/Spec defined values must also not be changed.
> >
> > With the switch to u32 we now can support devices with more than 255
> > ports. U32_MAX is reserved to make control logic a bit easier to deal
> > with. As a device with U32_MAX ports probably isn't going to happen
> > any time soon this seems like a non issue.
> >
> > When a device with more than 255 ports is created uverbs will report
> > the RDMA device as having 255 ports as this is the max currently supported.
> >
> > The verbs interface is not changed yet because the IBTA spec limits
> > the port size in too many places to be u8 and all applications that
> > relies in verbs won't be able to cope with this change. At this stage,
> > we are extending the interfaces that are using vendor channel solely
> >
> > Once the limitation is lifted mlx5 in switchdev mode will be able to
> > have thousands of SFs created by the device. As the only instance of
> > an RDMA device that reports more than 255 ports will be a representor
> > device and it exposes itself as a RAW Ethernet only device
> > CM/MAD/IPoIB and other ULPs aren't effected by this change and their
> > sysfs/interfaces that are exposes to userspace can remain unchanged.
> >
> > While here cleanup some alignment issues and remove unneeded sanity
> > checks (mainly in rdmavt),
> >
> > Signed-off-by: Mark Bloch <mbloch@nvidia.com>
> > Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> > ---
> 
> Applied to for-next, I suppose this means the irdma driver needs re-spinning
> already.
> 

Sure.