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Date: Thu, 15 Feb 2024 17:10:13 -0800
From: Jakub Kicinski <kuba@kernel.org>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Christoph Hellwig <hch@infradead.org>, Saeed Mahameed
 <saeed@kernel.org>, Arnd Bergmann <arnd@arndb.de>, Greg Kroah-Hartman
 <gregkh@linuxfoundation.org>, Leon Romanovsky <leonro@nvidia.com>, Jiri
 Pirko <jiri@nvidia.com>, Leonid Bloch <lbloch@nvidia.com>, Itay Avraham
 <itayavr@nvidia.com>, Saeed Mahameed <saeedm@nvidia.com>, David Ahern
 <dsahern@kernel.org>, Aron Silverton <aron.silverton@oracle.com>,
 andrew.gospodarek@broadcom.com, linux-kernel@vger.kernel.org,
 netdev@vger.kernel.org
Subject: Re: [PATCH V4 0/5] mlx5 ConnectX control misc driver
Message-ID: <20240215171013.60566d7b@kernel.org>
In-Reply-To: <20240215132138.GK1088888@nvidia.com>
References: <20240207072435.14182-1-saeed@kernel.org>
	<Zcx53N8lQjkpEu94@infradead.org>
	<20240214074832.713ca16a@kernel.org>
	<20240215132138.GK1088888@nvidia.com>
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On Thu, 15 Feb 2024 09:21:38 -0400 Jason Gunthorpe wrote:
> On Wed, Feb 14, 2024 at 07:48:32AM -0800, Jakub Kicinski wrote:
> > On Wed, 14 Feb 2024 00:29:16 -0800 Christoph Hellwig wrote:  
> > > With my busy kernel contributor head on I have to voice my
> > > dissatisfaction with the subsystem maintainer overreach that's causing
> > > the troubles here.   
> > 
> > Overreach is unfortunate, I'd love to say "please do merge it as part 
> > of RDMA". You probably don't trust my opinion but Jason admitted himself
> > this is primarily for RDMA.  
> 
> "admitted"? You make it sound like a crime. I've been very clear on
> this need from the RDMA community since the first posting.

Sorry, unintentional :) Maybe it's a misunderstanding but my impression
was that at least Saeed was trying hard to make this driver a common
one, not just for RDMA.

> > The problem is that some RDMA stuff is built really closely on TCP,  
> 
> Huh? Since when? Are you talking about soft-iwarp? That is a reasearch
> project and Bernard is very responsive, if you have issues ask him and
> he will help.
> 
> Otherwise the actual HW devices are not entangled with netdev TCP, the
> few iWarp devices have their own TCP implementation, in accordance
> with what the IETF standardized.

There are some things I know either from work or otherwise told me 
in confidence which I can't share. This is very frustrating for
me, and probably for you, sorry :(

> > and given Jason's and co. inability to understand that good fences
> > make good neighbors it will soon start getting into the netdev stack :|  
> 
> I seem to recall you saying RDMA shouldn't call any netdev APIs at
> all. We were unable to agree on where to build the fence for this
> reason.

Last time you were calling into the IPsec stack right? It's not just 
a basic API. IDK how to draw a line, definitely open to suggestions!

> > Ah, and I presume they may also want it for their DOCA products. 
> > So 80% RDMA, 15% DOCA, 5% the rest is my guess.  
> 
> I don't know all details about DOCA, but what I know about runs over
> RDMA.

Well, since you're an RDMA person that's not really saying much
about existence of other parts.