netdev - [PATCH] ibmveth: lost IRQ while closing/opening device leads to service loss

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Date:	Fri, 16 Jul 2010 09:57:25 -0500
From:	Robert Jennings <rcj@...ux.vnet.ibm.com>
To:	netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>,
	Santiago Leon <santil@...ux.vnet.ibm.com>,
	Brian King <brking@...ux.vnet.ibm.com>
Subject: [PATCH] ibmveth: lost IRQ while closing/opening device leads to
 service loss

The order of freeing the IRQ and freeing the device in firmware
in ibmveth_close can cause the adapter to become unusable after a
subsequent ibmveth_open.  Only a reboot of the OS will make the
network device usable again. This is seen when cycling the adapter
up and down while there is network activity.

There is a window where an IRQ will be left unserviced (H_EOI will not
be called).  The solution is to make a VIO_IRQ_DISABLE h_call, free the
device with firmware, and then call free_irq.

Signed-off-by: Robert Jennings <rcj@...ux.vnet.ibm.com>

---
No changes to the patch, I realized I left out '[PATCH]' in the subject
and I didn't want any automated tools missing this fix.

---
 drivers/net/ibmveth.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Index: b/drivers/net/ibmveth.c
===================================================================
--- a/drivers/net/ibmveth.c
+++ b/drivers/net/ibmveth.c
@@ -677,7 +677,7 @@ static int ibmveth_close(struct net_devi
 	if (!adapter->pool_config)
 		netif_stop_queue(netdev);
 
-	free_irq(netdev->irq, netdev);
+	h_vio_signal(adapter->vdev->unit_address, VIO_IRQ_DISABLE);
 
 	do {
 		lpar_rc = h_free_logical_lan(adapter->vdev->unit_address);
@@ -689,6 +689,8 @@ static int ibmveth_close(struct net_devi
 				     lpar_rc);
 	}
 
+	free_irq(netdev->irq, netdev);
+
 	adapter->rx_no_buffer = *(u64*)(((char*)adapter->buffer_list_addr) + 4096 - 8);
 
 	ibmveth_cleanup(adapter);
--
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