netdev - Re: [PATCH net-next] r8169: change wmb to smb_wmb in rtl8169_start

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Date:   Mon, 20 Apr 2020 16:04:07 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     hkallweit1@...il.com
Cc:     nic_swsd@...ltek.com, netdev@...r.kernel.org
Subject: Re: [PATCH net-next] r8169: change wmb to smb_wmb in
 rtl8169_start_xmit

From: Heiner Kallweit <hkallweit1@...il.com>
Date: Mon, 20 Apr 2020 22:52:59 +0200

> A barrier is needed here to ensure that rtl_tx sees the descriptor
> changes (DescOwn set) before the updated tp->cur_tx value. Else it may
> wrongly assume that the transfer has been finished already. For this
> purpose smp_wmb() is sufficient.
> 
> No separate barrier is needed for ordering the descriptor changes
> with the MMIO doorbell write. The needed barrier is included in
> the non-relaxed writel() used by rtl8169_doorbell().
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>

Applied, thanks.