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Date: Thu, 13 Jun 2024 08:40:42 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Larysa Zaremba <larysa.zaremba@intel.com>
Cc: <intel-wired-lan@lists.osuosl.org>, Jesse Brandeburg
 <jesse.brandeburg@intel.com>, Tony Nguyen <anthony.l.nguyen@intel.com>,
 "David S. Miller" <davem@davemloft.net>, Eric Dumazet
 <edumazet@google.com>, Paolo Abeni <pabeni@redhat.com>, Alexei Starovoitov
 <ast@kernel.org>, "Daniel Borkmann" <daniel@iogearbox.net>, Jesper Dangaard
 Brouer <hawk@kernel.org>, John Fastabend <john.fastabend@gmail.com>, Maciej
 Fijalkowski <maciej.fijalkowski@intel.com>, <netdev@vger.kernel.org>,
 <linux-kernel@vger.kernel.org>, <bpf@vger.kernel.org>,
 <magnus.karlsson@intel.com>, Michal Kubiak <michal.kubiak@intel.com>
Subject: Re: [PATCH iwl-net 0/3] ice: fix synchronization between .ndo_bpf()
 and reset
Message-ID: <20240613084042.7db4c410@kernel.org>
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On Thu, 13 Jun 2024 17:36:16 +0200 Larysa Zaremba wrote:
> > > AFAIK, netif_device_detach() does not affect .ndo_bpf() calls. We were trying 
> > > such approach with idpf and it does work for ethtool, but not for XDP.  
> > 
> > I reckon that's an unintentional omission. In theory XDP is "pure
> > software" but if the device is running driver will likely have to
> > touch HW to reconfigure. So, if you're willing, do send a ndo_bpf 
> > patch to add a detached check.  
> 
> This does not seem that simple. In cases of program/pool detachment, 
> .ndo_bpf() does not accept 'no' as an answer, so there is no easy existing way 
> of handling !netif_device_present() either. And we have to notify the driver 
> that pool/program is no longer needed no matter what. So what is left is somehow 
> postpone pool/prog removal to after the netdev gets attached again.

I see, thanks for investigating!