Re: [PATCH v1 1/4] xprtrdma: Remove support for FMR memory registration

[Leon Romanovsky <leon@kernel.org>]

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On Mon, Nov 19, 2018 at 08:16:37AM -0800, Bart Van Assche wrote:
> On Mon, 2018-11-19 at 10:45 -0500, Chuck Lever wrote:
> > FMR is not supported on most recent RDMA devices. It is also slower
> > and less secure than FRWR. As discussed during the RDMA BoF at LPC
> > 2018, it is time to remove support for FMR in the NFS/RDMA client
> > stack. NFS/RDMA server-side uses either local memory registration or
> > FRWR.  There is no change required there to deprecate FMR.
> >
> > There are a few Infiniband/RoCE devices in the kernel tree that do
> > not support MEM_MGT_EXTENSIONS, and therefore will no longer support
> > client-side NFS/RDMA. These are:
> >
> >  - mthca
> >  - qib
> >  - usnic
> >  - hns (RoCE)
>
> Can someone from Intel comment on how many of their customers rely on the qib
> driver?
>
> Can someone from Cisco comment on how many of their customers rely on the usnic
> driver?
>
> Can someone from Huawei comment on how many of their customers rely on the hns
> driver?
>
> I'm wondering whether I can remove FMR support from the SRP initiator driver.

Bart,

The more accurate question is "how many customers ... use latest,
upstream kernel?"

Thanks

>
> Thanks,
>
> Bart.

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