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Date: Tue, 21 May 2019 07:45:53 -0700
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH v2 net 2/2] net: core: generic XDP support for stacked
 device
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        <20190520091105.GA2142@nanopsycho>
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To: Jiri Pirko <jiri@resnulli.us>
Cc: netdev@vger.kernel.org, davem@davemloft.net, xdp-newbies@vger.kernel.org, bpf@vger.kernel.org, Stephen Hemminger <sthemmin@microsoft.com>, Jason Wang <jasowang@redhat.com>

On Tue, 21 May 2019 08:15:36 +0200
Jiri Pirko <jiri@resnulli.us> wrote:

> +	if (static_branch_unlikely(&generic_xdp_needed_key)) {
> +		int ret2;
> +
> +		preempt_disable();
> +		rcu_read_lock();
> +		ret2 = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb);
> +		rcu_read_unlock();
> +		preempt_enable();
> +
> +		if (ret2 != XDP_PASS)
> +			return NET_RX_DROP;
> +	}
> +

rcu_read_lock is already held by callers of __netif_receive_skb_core