RE: [RFC PATCH 00/10] net: hns3: Adds support of debugfs to HNS3 driver

[Salil Mehta]

Hi Andrew,
Thanks for replying. Sorry, for not being prompt as I was
traveling.

Please find some further follow-up questions below

Salil.

> From: linux-rdma-owner@xxxxxxxxxxxxxxx [mailto:linux-rdma-
> owner@xxxxxxxxxxxxxxx] On Behalf Of Andrew Lunn
> Sent: Friday, November 9, 2018 10:44 PM
> To: Salil Mehta <salil.mehta@xxxxxxxxxx>
> Cc: davem@xxxxxxxxxxxxx; yuvalm@xxxxxxxxxxxx; leon@xxxxxxxxxx;
> Zhuangyuzeng (Yisen) <yisen.zhuang@xxxxxxxxxx>; lipeng (Y)
> <lipeng321@xxxxxxxxxx>; mehta.salil@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; linux-rdma@xxxxxxxxxxxxxxx; Linuxarm
> <linuxarm@xxxxxxxxxx>
> Subject: Re: [RFC PATCH 00/10] net: hns3: Adds support of debugfs to
> HNS3 driver
> 
> > 3. Debugfs looks more unstructured unlike sysfs. Is there any
> >    de-facto standard of the user-api or drivers are allowed to
> >    use it in any way to expose the information from kernel.
> 
> Hi Salil
> 
> You don't really have a user api using debugfs, because debugfs is
> unstable. Anything can change at any time. Any user tools which use
> debugfs can be expected to break at any time as the information in
> debugfs changes. debugfs is for debug, not to export an API. And in
> production systems, it is often not mounted.


Sure, I understand. 

> 
> As much as possible, you are recommended to use existing APIs,
> ethtool, devlink, etc.


Agreed. But what about if we want to expose anything related to
firmware to user-space using the debugfs, assuming we are presenting
information in structured way and not as a black-box to some user-space
application. Is it something which might be discouraged?

Many Thanks