2016-07-28, 07:43:55 +0200, Eric Dumazet wrote:

On Wed, 2016-07-27 at 14:38 -0700, Jeff Kirsher wrote:

quoted

On Tue, 2016-07-26 at 11:14 +0200, Eric Dumazet wrote:

quoted

Could you try this ?

diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c

b/drivers/net/ethernet/intel/e1000/e1000_main.c
index
f42129d09e2c23ba9fdb5cde890d50ecb7166a42..a53c41c4c4f7d1fe52f95a2cab8784a
938b3820b 100644

--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c

@@ -5257,9 +5257,13 @@ static void e1000_netpoll(struct net_device

*netdev)
 {
        struct e1000_adapter *adapter = netdev_priv(netdev);
 
-       disable_irq(adapter->pdev->irq);
-       e1000_intr(adapter->pdev->irq, netdev);
-       enable_irq(adapter->pdev->irq);
+       if (napi_schedule_prep(&adapter->napi)) {
+               adapter->total_tx_bytes = 0;
+               adapter->total_tx_packets = 0;
+               adapter->total_rx_bytes = 0;
+               adapter->total_rx_packets = 0;
+               __napi_schedule(&adapter->napi);
+       }
 }
 #endif
 

Since this fixes the issue Fengguang saw, will you be submitting a formal
patch Eric? (please) I can get this queued up for Dave's net tree as soon
as I receive the formal patch.

I would prefer having a definitive advice from Thomas Gleixner and/or
others if disable_irq() is forbidden from IRQ path.

As I said, about all netpoll() methods in net drivers use disable_irq()
so a lot of patches would be needed.

disable_irq() should then test this condition earlier, so that we can
detect potential bug, even if the IRQ is not (yet) threaded.

The idea when this first came up was to skip the sleeping part of
disable_irq():

http://marc.info/?l=linux-netdev&m=142314159626052

This fell off my todolist and I didn't send the conversion patches,
which would basically look like this:

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 41f32c0b341e..b022691e680b 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c

@@ -6713,20 +6713,20 @@ static irqreturn_t e1000_intr_msix(int __always_unused irq, void *data)
 
 		vector = 0;
 		msix_irq = adapter->msix_entries[vector].vector;
-		disable_irq(msix_irq);
-		e1000_intr_msix_rx(msix_irq, netdev);
+		if (disable_hardirq(msix_irq))
+			e1000_intr_msix_rx(msix_irq, netdev);
 		enable_irq(msix_irq);
 
 		vector++;
 		msix_irq = adapter->msix_entries[vector].vector;
-		disable_irq(msix_irq);
-		e1000_intr_msix_tx(msix_irq, netdev);
+		if (disable_hardirq(msix_irq))
+			e1000_intr_msix_tx(msix_irq, netdev);
 		enable_irq(msix_irq);
 
 		vector++;
 		msix_irq = adapter->msix_entries[vector].vector;
-		disable_irq(msix_irq);
-		e1000_msix_other(msix_irq, netdev);
+		if (disable_hardirq(msix_irq))
+			e1000_msix_other(msix_irq, netdev);
 		enable_irq(msix_irq);
 	}
 

@@ -6750,13 +6750,13 @@ static void e1000_netpoll(struct net_device *netdev)
 		e1000_intr_msix(adapter->pdev->irq, netdev);
 		break;
 	case E1000E_INT_MODE_MSI:
-		disable_irq(adapter->pdev->irq);
-		e1000_intr_msi(adapter->pdev->irq, netdev);
+		if (disable_hardirq(adapter->pdev->irq))
+			e1000_intr_msi(adapter->pdev->irq, netdev);
 		enable_irq(adapter->pdev->irq);
 		break;
 	default:		/* E1000E_INT_MODE_LEGACY */
-		disable_irq(adapter->pdev->irq);
-		e1000_intr(adapter->pdev->irq, netdev);
+		if (disable_hardirq(adapter->pdev->irq))
+			e1000_intr(adapter->pdev->irq, netdev);
 		enable_irq(adapter->pdev->irq);
 		break;
 	}

-- 
Sabrina