intel drivers: repair missing flush operations

after review of all intel drivers, found several instances where
drivers had the incorrect pattern of:
memory mapped write();
delay();

which should always be:
memory mapped write();
write flush(); /* aka memory mapped read */
delay();

explanation:
The reason for including the flush is that writes can be held
(posted) in PCI/PCIe bridges, but the read always has to complete
synchronously and therefore has to flush all pending writes to a
device.  If a write is held and followed by a delay, the delay
means nothing because the write may not have reached hardware
(maybe even not until the next read)

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by:  Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index dc599059512a..ae3937e8cdef 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -1052,6 +1052,7 @@ msi_only:
 		kfree(adapter->vf_data);
 		adapter->vf_data = NULL;
 		wr32(E1000_IOVCTL, E1000_IOVCTL_REUSE_VFQ);
+		wrfl();
 		msleep(100);
 		dev_info(&adapter->pdev->dev, "IOV Disabled\n");
 	}
@@ -2198,6 +2199,7 @@ static void __devexit igb_remove(struct pci_dev *pdev)
 		kfree(adapter->vf_data);
 		adapter->vf_data = NULL;
 		wr32(E1000_IOVCTL, E1000_IOVCTL_REUSE_VFQ);
+		wrfl();
 		msleep(100);
 		dev_info(&pdev->dev, "IOV Disabled\n");
 	}