From: Stanislaw Gruszka <sgruszka@redhat.com>
Date: Thu, 25 Feb 2010 12:52:04 -0500
Subject: [net] bnx2x: use single tx queue
Message-id: <20100225135204.3913385c@dhcp-lab-109.englab.brq.redhat.com>
Patchwork-id: 23425
O-Subject: [RHEL5 PATCH] bnx2x: use single tx queue
Bugzilla: 567979
RH-Acked-by: Ivan Vecera <ivecera@redhat.com>
RH-Acked-by: Michal Schmidt <mschmidt@redhat.com>
RH-Acked-by: David S. Miller <davem@redhat.com>
RH-Acked-by: Andy Gospodarek <gospo@redhat.com>

BZ#567979

From:
Vladislav Zolotarov <vladz@broadcom.com>

Description:
We are using multi queue for transmit data, but single queue tx ON/OFF scheme.
That lead to race conditions when one queue can be full, but not stopped,
because other queue enable transmission.

To solve issue use single queue as it does not degrade performance, compared
what we have now (can not tx data on many cpu simultaneously due to locking).

Upstream:
Not related. Bug was introduced by me during 5.4 backporting.

Testing:
Vladislav Zolotarov confirm patch fix problem.


diff --git a/drivers/net/bnx2x_main.c b/drivers/net/bnx2x_main.c
index cb4d892..6a96d9c 100644
--- a/drivers/net/bnx2x_main.c
+++ b/drivers/net/bnx2x_main.c
@@ -11209,7 +11209,7 @@ static int bnx2x_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	fp_index = skb_get_queue_mapping(skb);
 	txq = netdev_get_tx_queue(dev, fp_index);
 #endif
-	fp_index = (smp_processor_id() % bp->num_queues);
+	fp_index = 0; /* no multi queue */
 
 	fp = &bp->fp[fp_index];