netdev - [PATCH 3/4] bnx2x: change smp_mb() comment to conform the true

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Message-Id: <1268153703-4186-3-git-send-email-sgruszka@redhat.com>
Date:	Tue,  9 Mar 2010 17:55:02 +0100
From:	Stanislaw Gruszka <sgruszka@...hat.com>
To:	netdev@...r.kernel.org
Cc:	Vladislav Zolotarov <vladz@...adcom.com>,
	Eilon Greenstein <eilong@...adcom.com>,
	Michael Chan <mchan@...adcom.com>,
	Stanislaw Gruszka <sgruszka@...hat.com>
Subject: [PATCH 3/4] bnx2x: change smp_mb() comment to conform the true

Access to fp->tx_bp_prod is protected by __netif_tx_lock,
smp_mb() is not needed for that.

Signed-off-by: Stanislaw Gruszka <sgruszka@...hat.com>
---
 drivers/net/bnx2x_main.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/bnx2x_main.c b/drivers/net/bnx2x_main.c
index ae62b67..6c042a7 100644
--- a/drivers/net/bnx2x_main.c
+++ b/drivers/net/bnx2x_main.c
@@ -11428,9 +11428,12 @@ static netdev_tx_t bnx2x_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	if (unlikely(bnx2x_tx_avail(fp) < MAX_SKB_FRAGS + 3)) {
 		netif_tx_stop_queue(txq);
-		/* We want bnx2x_tx_int to "see" the updated tx_bd_prod
-		   if we put Tx into XOFF state. */
+
+		/* paired memory barrier is in bnx2x_tx_int(), we have to keep
+		 * ordering of set_bit() in netif_tx_stop_queue() and read of
+		 * fp->bd_tx_cons */
 		smp_mb();
+
 		fp->eth_q_stats.driver_xoff++;
 		if (bnx2x_tx_avail(fp) >= MAX_SKB_FRAGS + 3)
 			netif_tx_wake_queue(txq);
-- 
1.6.2.5

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