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Date: Fri, 16 Aug 2024 11:38:38 +0200
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Kurt Kanzenbach <kurt@linutronix.de>
Cc: Tony Nguyen <anthony.l.nguyen@intel.com>,
	Przemek Kitszel <przemyslaw.kitszel@intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, 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>,
	Richard Cochran <richardcochran@gmail.com>,
	Sriram Yagnaraman <sriram.yagnaraman@ericsson.com>,
	Benjamin Steinke <benjamin.steinke@woks-audio.com>,
	Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
	intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
	bpf@vger.kernel.org, Sriram Yagnaraman <sriram.yagnaraman@est.tech>
Subject: Re: [PATCH iwl-next v6 1/6] igb: Always call
 igb_xdp_ring_update_tail() under Tx lock
Message-ID: <20240816093838.ZpGD38t-@linutronix.de>
References: <20240711-b4-igb_zero_copy-v6-0-4bfb68773b18@linutronix.de>
 <20240711-b4-igb_zero_copy-v6-1-4bfb68773b18@linutronix.de>
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In-Reply-To: <20240711-b4-igb_zero_copy-v6-1-4bfb68773b18@linutronix.de>

On 2024-08-16 11:24:00 [+0200], Kurt Kanzenbach wrote:
> index 11be39f435f3..4d5e5691c9bd 100644
> --- a/drivers/net/ethernet/intel/igb/igb_main.c
> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> @@ -2914,6 +2914,7 @@ static int igb_xdp(struct net_device *dev, struct netdev_bpf *xdp)
>  	}
>  }
>  
> +/* This function assumes __netif_tx_lock is held by the caller. */
>  static void igb_xdp_ring_update_tail(struct igb_ring *ring)
>  {
>  	/* Force memory writes to complete before letting h/w know there
This
  lockdep_assert_held(txring_txq(ring)->_xmit_lock);
would be more powerful than the comment ;)

Sebastian