drivers: net: xgene: fix extra IRQ issue

BugLink: http://bugs.launchpad.net/bugs/1611399

For interrupt controller that doesn't support irq_disable and hardware
with level interrupt, an extra interrupt may be pending. This patch fixes
the issue by setting IRQ_DISABLE_UNLAZY flag for the interrupt line,
as suggested by,

'commit e9849777 ("genirq: Add flag to force mask in
		       disable_irq[_nosync]()")'
Signed-off-by: Iyappan Subramanian <isubramanian@apm.com>
Tested-by: Toan Le <toanle@apm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit b5d7a069 linux-next)
Signed-off-by: Craig Magina <craig.magina@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/net/ethernet/apm/xgene/xgene_enet_main.c

@@ -628,6 +628,7 @@ static int xgene_enet_register_irq(struct net_device *ndev)
 	int ret;
 
 	ring = pdata->rx_ring;
+	irq_set_status_flags(ring->irq, IRQ_DISABLE_UNLAZY);
 	ret = devm_request_irq(dev, ring->irq, xgene_enet_rx_irq,
 			       IRQF_SHARED, ring->irq_name, ring);
 	if (ret)
@@ -635,6 +636,7 @@ static int xgene_enet_register_irq(struct net_device *ndev)
 
 	if (pdata->cq_cnt) {
 		ring = pdata->tx_ring->cp_ring;
+		irq_set_status_flags(ring->irq, IRQ_DISABLE_UNLAZY);
 		ret = devm_request_irq(dev, ring->irq, xgene_enet_rx_irq,
 				       IRQF_SHARED, ring->irq_name, ring);
 		if (ret) {
@@ -649,15 +651,19 @@ static int xgene_enet_register_irq(struct net_device *ndev)
 static void xgene_enet_free_irq(struct net_device *ndev)
 {
 	struct xgene_enet_pdata *pdata;
+	struct xgene_enet_desc_ring *ring;
 	struct device *dev;
 
 	pdata = netdev_priv(ndev);
 	dev = ndev_to_dev(ndev);
-	devm_free_irq(dev, pdata->rx_ring->irq, pdata->rx_ring);
+	ring = pdata->rx_ring;
+	irq_clear_status_flags(ring->irq, IRQ_DISABLE_UNLAZY);
+	devm_free_irq(dev, ring->irq, ring);
 
 	if (pdata->cq_cnt) {
-		devm_free_irq(dev, pdata->tx_ring->cp_ring->irq,
-			      pdata->tx_ring->cp_ring);
+		ring = pdata->tx_ring->cp_ring;
+		irq_clear_status_flags(ring->irq, IRQ_DISABLE_UNLAZY);
+		devm_free_irq(dev, ring->irq, ring);
 	}
 }
 

drivers/net/ethernet/apm/xgene/xgene_enet_main.h

@@ -25,6 +25,7 @@
 #include <linux/acpi.h>
 #include <linux/clk.h>
 #include <linux/efi.h>
+#include <linux/irq.h>
 #include <linux/io.h>
 #include <linux/of_platform.h>
 #include <linux/of_net.h>