net: ethernet: sxgbe: remove private tx queue lock

The driver uses a private lock for synchronization of the xmit function and
the xmit completion handler, but since the NETIF_F_LLTX flag is not set,
the xmit function is also called with the xmit_lock held.

On the other hand the completion handler uses the reverse locking order by
first taking the private lock and (in case that the tx queue had been
stopped) then the xmit_lock.

Improve the locking by removing the private lock and using only the
xmit_lock for synchronization instead.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/samsung/sxgbe/sxgbe_common.h b/drivers/net/ethernet/samsung/sxgbe/sxgbe_common.h
index 5cb51b609f02cb3498271fcf1e82dfecf83c5d35..c61f260e18a48dc0ce3a672dc2455f4afacb4f5d 100644 (file)
--- a/drivers/net/ethernet/samsung/sxgbe/sxgbe_common.h
+++ b/drivers/net/ethernet/samsung/sxgbe/sxgbe_common.h
@@ -384,7 +384,6 @@ struct sxgbe_tx_queue {
        dma_addr_t *tx_skbuff_dma;
        struct sk_buff **tx_skbuff;
        struct timer_list txtimer;
-       spinlock_t tx_lock;     /* lock for tx queues */
        unsigned int cur_tx;
        unsigned int dirty_tx;
        u32 tx_count_frames;

diff --git a/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c b/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c
index 5dbe40640da6931c35e9dd763b6cb6e28d141d9f..cddcff5a00a7c63a7e426b601de990c8f5b269cf 100644 (file)
--- a/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c
+++ b/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c
@@ -426,9 +426,6 @@ static int init_tx_ring(struct device *dev, u8 queue_no,
        tx_ring->dirty_tx = 0;
        tx_ring->cur_tx = 0;
 
-       /* initialise TX queue lock */
-       spin_lock_init(&tx_ring->tx_lock);
-
        return 0;
 
 dmamem_err:
@@ -743,7 +740,7 @@ static void sxgbe_tx_queue_clean(struct sxgbe_tx_queue *tqueue)
 
        dev_txq = netdev_get_tx_queue(priv->dev, queue_no);
 
-       spin_lock(&tqueue->tx_lock);
+       __netif_tx_lock(dev_txq, smp_processor_id());
 
        priv->xstats.tx_clean++;
        while (tqueue->dirty_tx != tqueue->cur_tx) {
@@ -781,18 +778,13 @@ static void sxgbe_tx_queue_clean(struct sxgbe_tx_queue *tqueue)
 
        /* wake up queue */
        if (unlikely(netif_tx_queue_stopped(dev_txq) &&
-                    sxgbe_tx_avail(tqueue, tx_rsize) > SXGBE_TX_THRESH(priv))) {
-               netif_tx_lock(priv->dev);
-               if (netif_tx_queue_stopped(dev_txq) &&
-                   sxgbe_tx_avail(tqueue, tx_rsize) > SXGBE_TX_THRESH(priv)) {
-                       if (netif_msg_tx_done(priv))
-                               pr_debug("%s: restart transmit\n", __func__);
-                       netif_tx_wake_queue(dev_txq);
-               }
-               netif_tx_unlock(priv->dev);
+           sxgbe_tx_avail(tqueue, tx_rsize) > SXGBE_TX_THRESH(priv))) {
+               if (netif_msg_tx_done(priv))
+                       pr_debug("%s: restart transmit\n", __func__);
+               netif_tx_wake_queue(dev_txq);
        }
 
-       spin_unlock(&tqueue->tx_lock);
+       __netif_tx_unlock(dev_txq);
 }
 
 /**
@@ -1304,9 +1296,6 @@ static netdev_tx_t sxgbe_xmit(struct sk_buff *skb, struct net_device *dev)
                      tqueue->hwts_tx_en)))
                ctxt_desc_req = 1;
 
-       /* get the spinlock */
-       spin_lock(&tqueue->tx_lock);
-
        if (priv->tx_path_in_lpi_mode)
                sxgbe_disable_eee_mode(priv);
 
@@ -1316,8 +1305,6 @@ static netdev_tx_t sxgbe_xmit(struct sk_buff *skb, struct net_device *dev)
                        netdev_err(dev, "%s: Tx Ring is full when %d queue is awake\n",
                                   __func__, txq_index);
                }
-               /* release the spin lock in case of BUSY */
-               spin_unlock(&tqueue->tx_lock);
                return NETDEV_TX_BUSY;
        }
 
@@ -1436,8 +1423,6 @@ static netdev_tx_t sxgbe_xmit(struct sk_buff *skb, struct net_device *dev)
 
        priv->hw->dma->enable_dma_transmission(priv->ioaddr, txq_index);
 
-       spin_unlock(&tqueue->tx_lock);
-
        return NETDEV_TX_OK;
 }