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Date: Tue, 2 Apr 2024 14:36:07 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Leon Romanovsky <leon@kernel.org>, David Ahern <dsahern@kernel.org>,
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Christoph Hellwig
 <hch@infradead.org>, Saeed Mahameed <saeed@kernel.org>, Arnd Bergmann
 <arnd@arndb.de>, Jiri Pirko <jiri@nvidia.com>, Leonid Bloch
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 <netdev@vger.kernel.org>, Andy Gospodarek <andrew.gospodarek@broadcom.com>,
 Junxian Huang <huangjunxian6@hisilicon.com>
Subject: Re: [PATCH V4 0/5] mlx5 ConnectX control misc driver
Message-ID: <20240402143607.0357d71a@kernel.org>
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On Tue, 2 Apr 2024 15:45:54 -0300 Jason Gunthorpe wrote:
> On Mon, Apr 01, 2024 at 07:50:03AM -0700, Jakub Kicinski wrote:
> > On Mon, 1 Apr 2024 15:30:03 +0300 Leon Romanovsky wrote:  
> > > HNS driver is a good example of such device. It has nothing to do with
> > > netdev and needs common and reliable way to configure FW.  
> > 
> > Sorry, I have a completely different reading of that thread.
> > Thanks for bringing it up, tho.
> > 
> > As I said multiple times I agree that configuring custom parameters
> > in RDMA is a necessity. Junxian's approach of putting such code in
> > the RDMA driver / subsystem is more than reasonable. Even better,
> > it looks like the API is fairly narrowly defined.  
> 
> Uh, if I understand netdev rules aren't read/write sysfs created from
> drivers banned? 

Neither is that true as an absolute "netdev rule" nor relevant 
to the discussion.

> So reasonable for RDMA but unacceptable to netdev?

I don't know or care what interface guidance you provide.
What I called reasonable is putting that code in RDMA driver
/ subsystem.

> My brain hurts.

Maybe brains are better suited for understanding what other people
say rather than twisting and misinterpreting..

> FWIW, I've been trying to push RDMA away from driver created sysfs for
> a while now. Aside from the API complexity, implementations have
> messed up using the sysfs APIs and resulted in some significant
> problems :(

Sure, agreed, but off-topic.