The driver uses a private lock for synchronization between 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 xmit completion handler first takes the private lock
and (in case that the tx queue has been stopped) the xmit_lock, leading
to a reverse locking order and the potential danger of a deadlock.
Fix this by removing the private lock completely and synchronizing the xmit
function and completion handler solely by means of the xmit_lock. By doing
this also remove the now unnecessary double check for a stopped tx queue.
Signed-off-by: Lino Sanfilippo <linosanfili...@gmx.de>
---
drivers/net/ethernet/samsung/sxgbe/sxgbe_common.h | 1 -
drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c | 27 +++++------------------
2 files changed, 6 insertions(+), 22 deletions(-)
diff --git a/drivers/net/ethernet/samsung/sxgbe/sxgbe_common.h
b/drivers/net/ethernet/samsung/sxgbe/sxgbe_common.h
index 5cb51b6..c61f260 100644
--- 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 ea44a24..22d3b0b 100644
--- 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;
}
--
1.9.1
