netdev - [PATCH net-next] r8169: handle all interrupt events in the hard irq handler

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Date:   Thu, 18 Oct 2018 22:19:28 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     David Miller <davem@...emloft.net>,
        Realtek linux nic maintainers <nic_swsd@...ltek.com>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH net-next] r8169: handle all interrupt events in the hard irq
 handler

Having a separate "slow event" handler isn't needed because all
interrupt events trigger asynchronous activity. And in case of SYSErr
we have bigger problems than performance anyway.
This patch also allows to get rid of acking interrupt events in the
NAPI poll callback.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
This patch will apply to net-next only after 6b839b6cf9ea ("r8169: fix
NAPI handling under high load") was merged from net to net-next.
---
 drivers/net/ethernet/realtek/r8169.c | 65 ++++++++--------------------
 1 file changed, 19 insertions(+), 46 deletions(-)

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index 03d5fb7c7..3075b493d 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -631,7 +631,6 @@ struct rtl8169_tc_offsets {
 
 enum rtl_flag {
 	RTL_FLAG_TASK_ENABLED = 0,
-	RTL_FLAG_TASK_SLOW_PENDING,
 	RTL_FLAG_TASK_RESET_PENDING,
 	RTL_FLAG_MAX
 };
@@ -6460,42 +6459,29 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
 	if (status == 0xffff || !(status & (RTL_EVENT_NAPI | tp->event_slow)))
 		return IRQ_NONE;
 
-	rtl_irq_disable(tp);
-	napi_schedule_irqoff(&tp->napi);
-
-	return IRQ_HANDLED;
-}
-
-/*
- * Workqueue context.
- */
-static void rtl_slow_event_work(struct rtl8169_private *tp)
-{
-	struct net_device *dev = tp->dev;
-	u16 status;
+	if (unlikely(status & SYSErr)) {
+		rtl8169_pcierr_interrupt(tp->dev);
+		goto out;
+	}
 
-	status = rtl_get_events(tp) & tp->event_slow;
-	rtl_ack_events(tp, status);
+	if (status & LinkChg)
+		phy_mac_interrupt(tp->dev->phydev);
 
-	if (unlikely(status & RxFIFOOver)) {
-		switch (tp->mac_version) {
-		/* Work around for rx fifo overflow */
-		case RTL_GIGA_MAC_VER_11:
-			netif_stop_queue(dev);
-			/* XXX - Hack alert. See rtl_task(). */
-			set_bit(RTL_FLAG_TASK_RESET_PENDING, tp->wk.flags);
-		default:
-			break;
-		}
+	if (unlikely(status & RxFIFOOver &&
+	    tp->mac_version == RTL_GIGA_MAC_VER_11)) {
+		netif_stop_queue(tp->dev);
+		/* XXX - Hack alert. See rtl_task(). */
+		set_bit(RTL_FLAG_TASK_RESET_PENDING, tp->wk.flags);
 	}
 
-	if (unlikely(status & SYSErr))
-		rtl8169_pcierr_interrupt(dev);
-
-	if (status & LinkChg)
-		phy_mac_interrupt(dev->phydev);
+	if (status & RTL_EVENT_NAPI) {
+		rtl_irq_disable(tp);
+		napi_schedule_irqoff(&tp->napi);
+	}
+out:
+	rtl_ack_events(tp, status);
 
-	rtl_irq_enable_all(tp);
+	return IRQ_HANDLED;
 }
 
 static void rtl_task(struct work_struct *work)
@@ -6504,8 +6490,6 @@ static void rtl_task(struct work_struct *work)
 		int bitnr;
 		void (*action)(struct rtl8169_private *);
 	} rtl_work[] = {
-		/* XXX - keep rtl_slow_event_work() as first element. */
-		{ RTL_FLAG_TASK_SLOW_PENDING,	rtl_slow_event_work },
 		{ RTL_FLAG_TASK_RESET_PENDING,	rtl_reset_work },
 	};
 	struct rtl8169_private *tp =
@@ -6535,27 +6519,16 @@ static int rtl8169_poll(struct napi_struct *napi, int budget)
 {
 	struct rtl8169_private *tp = container_of(napi, struct rtl8169_private, napi);
 	struct net_device *dev = tp->dev;
-	u16 enable_mask = RTL_EVENT_NAPI | tp->event_slow;
 	int work_done;
-	u16 status;
-
-	status = rtl_get_events(tp);
-	rtl_ack_events(tp, status & ~tp->event_slow);
 
 	work_done = rtl_rx(dev, tp, (u32) budget);
 
 	rtl_tx(dev, tp);
 
-	if (status & tp->event_slow) {
-		enable_mask &= ~tp->event_slow;
-
-		rtl_schedule_task(tp, RTL_FLAG_TASK_SLOW_PENDING);
-	}
-
 	if (work_done < budget) {
 		napi_complete_done(napi, work_done);
 
-		rtl_irq_enable(tp, enable_mask);
+		rtl_irq_enable_all(tp);
 		mmiowb();
 	}
 
-- 
2.19.1