netdev - Re: r8169: improve spurious interrupt detection

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Message-Id: <20181215.103543.935738830761092732.davem@davemloft.net>
Date:   Sat, 15 Dec 2018 10:35:43 -0800 (PST)
From:   David Miller <davem@...emloft.net>
To:     hkallweit1@...il.com
Cc:     nic_swsd@...ltek.com, netdev@...r.kernel.org
Subject: Re: r8169: improve spurious interrupt detection

From: Heiner Kallweit <hkallweit1@...il.com>
Date: Sat, 15 Dec 2018 16:24:02 +0100

> @@ -6405,8 +6405,9 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
>  {
>  	struct rtl8169_private *tp = dev_instance;
>  	u16 status = rtl_get_events(tp);
> +	u16 irq_mask = RTL_R16(tp, IntrMask);
>  
> -	if (status == 0xffff || !(status & tp->irq_mask))
> +	if (status == 0xffff || !(status & irq_mask))
>  		return IRQ_NONE;

Heiner, this is really expensive.  Why is the tp->irq_mask value out of
sync with the value programmed into IntrMask?  Is there some way we can
fix that instead?