Re: [PATCH for-next 0/2] IB/opa_vnic: Add debugfs interface

[Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>]

On Thu, Sep 28, 2017 at 10:37:40PM +0300, Leon Romanovsky wrote:

> > We find it useful on an ongoing basis, more like some standard NICs
> > providing debugfs interface to read/write from/to some of its registers.
> 
> Usually if such interface is spotted during submission, it will be requested
> to drop it. Ask Salil, who lately upstreamed new ETH driver and was asked
> to remove it.

To be fair Salil's was dropped more or less for security reasons..

I think debugfs to dump truely internal state that is not intended to
be API stable is reasonable.

Promise you will not be tooling on top of this, or use it as an
interface in your manager or something crazy like that. You must be
happy in all cases if your distro chooses to disable debugfs.

The problem I have with reviewing all the vnic patches is that I don't
have a spec for vnic or anything, and I don't really know what the
data being dumped is.. eg I would have been much happier if ipoib
dump'd its debugfs stuff through netlink connected to neighbor objects
- I don't know if this is something similar...

As Leon says, you should really think carefully if this needs to be
something that admins are going to be told to look at when vnic isn't
working properly, as the ipoib debufs is. In that case netlink is a
stable API and more suitable.

Jason
--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html