r8169: remove member irq_enabled from struct rtl8169_private

After making use of the gro_flush_timeout attribute I once got a
tx timeout due to an interrupt that wasn't handled. Seems using
irq_enabled can be racy, and it's not needed any longer anyway,
so remove it. I've never seen a report about such a race before,
therefore treat the change as an improvement.

There's just one small drawback: If a legacy PCI interrupt is used,
and if this interrupt is shared with a device with high interrupt
rate, then we may handle interrupts even if NAPI disabled them,
and we may see a certain performance decrease under high network load.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169_main.c

@@ -617,7 +617,6 @@ struct rtl8169_private {
  struct work_struct work;
  } wk;
 
- unsigned irq_enabled:1;
  unsigned supports_gmii:1;
  unsigned aspm_manageable:1;
  dma_addr_t counters_phys_addr;
@@ -1280,12 +1279,10 @@ static void rtl_irq_disable(struct rtl8169_private *tp)
  RTL_W32(tp, IntrMask_8125, 0);
  else
  RTL_W16(tp, IntrMask, 0);
- tp->irq_enabled = 0;
 }
 
 static void rtl_irq_enable(struct rtl8169_private *tp)
 {
- tp->irq_enabled = 1;
  if (rtl_is_8125(tp))
  RTL_W32(tp, IntrMask_8125, tp->irq_mask);
  else
@@ -4541,8 +4538,7 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
  struct rtl8169_private *tp = dev_instance;
  u32 status = rtl_get_events(tp);
 
- if (!tp->irq_enabled || (status & 0xffff) == 0xffff ||
- !(status & tp->irq_mask))
+ if ((status & 0xffff) == 0xffff || !(status & tp->irq_mask))
  return IRQ_NONE;
 
  if (unlikely(status & SYSErr)) {