netdev - [PATCH 2/2] net: ethernet: altera: TSE: do not use tx queue lock in tx completion handler

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Date:   Wed, 30 Nov 2016 23:48:32 +0100
From:   Lino Sanfilippo <LinoSanfilippo@....de>
To:     vbridger@...nsource.altera.com
Cc:     nios2-dev@...ts.rocketboards.org, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, Lino Sanfilippo <LinoSanfilippo@....de>
Subject: [PATCH 2/2] net: ethernet: altera: TSE: do not use tx queue lock in tx completion handler

The driver already uses its private lock for synchronization between xmit
and xmit completion handler making the additional use of the xmit_lock
unnecessary.
Furthermore the driver does not set NETIF_F_LLTX resulting in xmit to be
called with the xmit_lock held and then taking the private lock while xmit
completion handler does the reverse, first take the private lock, then the
xmit_lock.
Fix these issues by not taking the xmit_lock in the tx completion handler.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@....de>
---
 drivers/net/ethernet/altera/altera_tse_main.c | 2 --
 1 file changed, 2 deletions(-)

 Please note that this is only compile tested since I do not have the
 concerning hardware.

diff --git a/drivers/net/ethernet/altera/altera_tse_main.c b/drivers/net/ethernet/altera/altera_tse_main.c
index 16c4163..cddc532 100644
--- a/drivers/net/ethernet/altera/altera_tse_main.c
+++ b/drivers/net/ethernet/altera/altera_tse_main.c
@@ -463,7 +463,6 @@ static int tse_tx_complete(struct altera_tse_private *priv)
 
 	if (unlikely(netif_queue_stopped(priv->dev) &&
 		     tse_tx_avail(priv) > TSE_TX_THRESH(priv))) {
-		netif_tx_lock(priv->dev);
 		if (netif_queue_stopped(priv->dev) &&
 		    tse_tx_avail(priv) > TSE_TX_THRESH(priv)) {
 			if (netif_msg_tx_done(priv))
@@ -471,7 +470,6 @@ static int tse_tx_complete(struct altera_tse_private *priv)
 					   __func__);
 			netif_wake_queue(priv->dev);
 		}
-		netif_tx_unlock(priv->dev);
 	}
 
 	spin_unlock(&priv->tx_lock);
-- 
2.7.4