From: Andy Gospodarek <gospo@redhat.com>
Date: Fri, 10 Jul 2009 14:56:54 -0400
Subject: [net] be2net: fix msix performance regression
Message-id: 20090710185654.GX20245@gospo.rdu.redhat.com
O-Subject: [RHEL5.4 PATCH] be2net: fix msix performance regression
Bugzilla: 510008
RH-Acked-by: David Miller <davem@redhat.com>
RH-Acked-by: Dean Nelson <dnelson@redhat.com>
RH-Acked-by: Stefan Assmann <sassmann@redhat.com>

This should be the final patch needed to resolve be2net problems on 5.4.
This is the description of the problem and solution from the vendor:

"This patch fixes a problem where with MSIX where we may return without
clearing interrupt which will cause us to return to ISR bringing
performance down due to too many interrupts.

"This bug was introduced as part of the changes to fix for 508839.  This
problem does not exist in the upstream driver and hence will not be
submitted to upstream."

This will resolve RHBZ 510008.

diff --git a/drivers/net/benet/be_main.c b/drivers/net/benet/be_main.c
index 4e99887..5c9be2b 100644
--- a/drivers/net/benet/be_main.c
+++ b/drivers/net/benet/be_main.c
@@ -1233,6 +1233,9 @@ static irqreturn_t be_msix(int irq, void *dev)
 	struct be_eq_obj *eq_obj = &adapter->be_eq;
 	struct be_eq_entry *entry = queue_tail_node(&eq_obj->q);
 
+	/* Clear the interrupt */
+	be_eq_notify(&adapter->ctrl, eq_obj->q.id, false, true, 0);
+
 	if (entry->evt)
 		compat_napi_schedule(&adapter->napi);
 
@@ -1276,12 +1279,8 @@ int be_poll_rx(struct be_adapter *adapter, int budget)
 	if (atomic_read(&adapter->rx_obj.q.used) < RX_FRAGS_REFILL_WM)
 		be_post_rx_frags(adapter);
 
-	if (work) {
-		if (work < budget)
-			be_cq_notify(&adapter->ctrl, rx_cq->id, true, work);
-		else
-			be_cq_notify(&adapter->ctrl, rx_cq->id, false, work);
-	}
+	if (work)
+		be_cq_notify(&adapter->ctrl, rx_cq->id, true, work);
 
 	return work;
 }
@@ -1337,13 +1336,13 @@ int be_poll(struct napi_struct *napi, int budget)
 	be_process_mcc(&adapter->ctrl);
 
 	/* All consumed */
-	if (rx_work < budget)
+	if (rx_work < budget) {
 		compat_napi_complete(napi);
+		be_eq_notify(ctrl, eq_obj->q.id, true, false, num);
+	} else
+		be_eq_notify(ctrl, eq_obj->q.id, false, false, num);
 
 	drvr_stats(adapter)->be_num_events += num;
-	if (num)
-		be_eq_notify(ctrl, eq_obj->q.id, true, true, num);
-
 	return rx_work;
 }