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Date:   Fri, 19 Jan 2018 18:14:42 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Francois Romieu <romieu@fr.zoreil.com>
Cc:     Jia-Ju Bai <baijiaju1990@gmail.com>, nic_swsd@realtek.com,
        alexander.h.duyck@redhat.com, David Miller <davem@davemloft.net>,
        dhowells@redhat.com, paulmck@linux.vnet.ibm.com,
        will.deacon@arm.com, netdev@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: net: r8169: a question of memory barrier in the r8169 driver
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On Fri, Jan 19, 2018 at 02:11:18AM +0100, Francois Romieu wrote:
> Peter Zijlstra <peterz@infradead.org> :
> [...]
> > There is only 1 variable afaict. Memory barriers need at least 2 in
> > order to be able to do _anything_.
> 
> I don't get your point: why don't {cur_tx, dirty_tx} qualify as said
> two variables ?

There wasn't any cur_tx in the code you provided.