[patch 016/108] e1000e: stop unnecessary polling when using msi-x

Greg KH
2009-07-01T00:51:27Z

[-- Attachment #1: e1000e-stop-unnecessary-polling-when-using-msi-x.patch --]
[-- Type: text/plain, Size: 1570 bytes --]

2.6.30-stable review patch. If anyone has any objections, please let us know.

------------------

From: Andy Gospodarek <andy@greyhouse.net>

[ Upstream commit 679e8a0f0ae3333e94b1d374d07775fce9066025 ]

The last hunk of this commit:

commit 12d04a3c12b420f23398b4d650127642469a60a6
Author: Alexander Duyck <alexander.h.duyck@intel.com>
Date: Wed Mar 25 22:05:03 2009 +0000

e1000e: commonize tx cleanup routine to match e1000 & igb

changed the logic for determining if we should call napi_complete or
not at then end of a napi poll.

If the NIC is using MSI-X with no work to do in ->poll, net_rx_action
can just spin indefinitely on older kernels and for 2 jiffies on newer
kernels since napi_complete is never called and budget isn't
decremented.

Discovered and verified while testing driver backport to an older
kernel.

Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/net/e1000e/netdev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -1996,7 +1996,7 @@ static int e1000_clean(struct napi_struc
struct e1000_adapter *adapter = container_of(napi, struct e1000_adapter, napi);
struct e1000_hw *hw = &adapter->hw;
struct net_device *poll_dev = adapter->netdev;
- int tx_cleaned = 0, work_done = 0;
+ int tx_cleaned = 1, work_done = 0;

adapter = netdev_priv(poll_dev);