Re: [PATCH v3 00/14] Adding GAUDI NIC code to habanalabs driver

From: Oded Gabbay <oded.gabbay@gmail.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Jakub Kicinski <kuba@kernel.org>,
	"Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>,
	netdev@vger.kernel.org, SW_Drivers <SW_Drivers@habana.ai>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"David S. Miller" <davem@davemloft.net>,
	Florian Fainelli <f.fainelli@gmail.com>,
	linux-rdma@vger.kernel.org
Subject: Re: [PATCH v3 00/14] Adding GAUDI NIC code to habanalabs driver
Date: Wed, 16 Sep 2020 00:43:00 +0300	[thread overview]
Message-ID: <CAFCwf13RHWmpAXpWLRtsxjvKPK=7ZChDPD9E6KEgbamLbg09OA@mail.gmail.com> (raw)
In-Reply-To: <20200915213735.GG3526428@lunn.ch>

On Wed, Sep 16, 2020 at 12:37 AM Andrew Lunn <andrew@lunn.ch> wrote:
>
> > I completely understand but you didn't answer my question. How come
> > there are drivers which create netdev objects, and specifically sgi-xp
> > in misc (but I also saw it in usb drivers) that live outside
> > drivers/net ? Why doesn't your request apply to them as well ?
> > When we wrote the code, we saw those examples and therefore assumed it was fine.
>
> commit 45d9ca492e4bd1522d1b5bd125c2908f1cee3d4a
> Author: Dean Nelson <dcn@sgi.com>
> Date:   Tue Apr 22 14:46:56 2008 -0500
>
>     [IA64] move XP and XPC to drivers/misc/sgi-xp
>
>     Move XPC and XPNET from arch/ia64/sn/kernel to drivers/misc/sgi-xp.
>
>     Signed-off-by: Dean Nelson <dcn@sgi.com>
>     Signed-off-by: Tony Luck <tony.luck@intel.com>
>
> It has been there a long time, and no networking person was involved
> in its move.
>
> drivers/usb/gadget/function/f_ncm.c
> commit 00a2430ff07d4e0e0e7e24e02fd8adede333b797
> Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
> Date:   Tue Jul 15 13:09:46 2014 +0200
>
>     usb: gadget: Gadget directory cleanup - group usb functions
>
>     The drivers/usb/gadget directory contains many files.
>     Files which are related can be distributed into separate directories.
>     This patch moves the USB functions implementations into a separate directory.
>
>     Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
>     Signed-off-by: Felipe Balbi <balbi@ti.com>
>
> Again, old.
>
> Can you find an example of a network driver added in the last couple
> of years outside of drivers/met?
I honestly don't know and I admit we didn't look at the dates of when
these drivers were introduced.
Oded

>
> > > > > Please make sure to CC linux-rdma. You clearly stated that the device
> > > > > does RDMA-like transfers.
> > > >
> > > > We don't use the RDMA infrastructure in the kernel and we can't
> > > > connect to it due to the lack of H/W support we have so I don't see
> > > > why we need to CC linux-rdma.
> > >
> > > You have it backward. You don't get to pick and choose which parts of
> > > the infrastructure you use, and therefore who reviews your drivers.
> > > The device uses RDMA under the hood so Linux RDMA experts must very
> > > much be okay with it getting merged. That's how we ensure Linux
> > > interfaces are consistent and good quality.
> >
> > I understand your point of view but If my H/W doesn't support the
> > basic requirements of the RDMA infrastructure and interfaces, then
> > really there is nothing I can do about it. I can't use them.
>
> It is up to the RDMA people to say that. They might see how the RDMA
> core can be made to work for your hardware.
>
>      Andrew