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Date: Thu, 25 Jul 2024 06:38:58 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Cc: Tony Nguyen <anthony.l.nguyen@intel.com>, <davem@davemloft.net>,
 <pabeni@redhat.com>, <edumazet@google.com>, <netdev@vger.kernel.org>,
 <magnus.karlsson@intel.com>, <aleksander.lobakin@intel.com>,
 <ast@kernel.org>, <daniel@iogearbox.net>, <hawk@kernel.org>,
 <john.fastabend@gmail.com>, <bpf@vger.kernel.org>, Shannon Nelson
 <shannon.nelson@amd.com>, Chandan Kumar Rout <chandanx.rout@intel.com>
Subject: Re: [PATCH net 6/8] ice: improve updating ice_{t,
 r}x_ring::xsk_pool
Message-ID: <20240725063858.65803c85@kernel.org>
In-Reply-To: <ZqEieHlPdMZcPGXI@boxer>
References: <20240708221416.625850-1-anthony.l.nguyen@intel.com>
	<20240708221416.625850-7-anthony.l.nguyen@intel.com>
	<20240709184524.232b9f57@kernel.org>
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On Wed, 24 Jul 2024 17:49:12 +0200 Maciej Fijalkowski wrote:
> > So if we are already in the af_xdp handler, and update patch sets pool
> > to NULL - the af_xdp handler will be fine with the pool becoming NULL?
> > I guess it may be fine, it's just quite odd to call the function called
> > _ONCE() multiple times..  
> 
> Update path before NULLing pool will go through rcu grace period, stop
> napis, disable irqs, etc. Running napi won't be exposed to nulled pool in
> such case.

Could you make it clearer what condition the patch is fixing, then?
What can go wrong without this patch?