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 remove also the now unnecessary double check for a stopped tx queue.
Signed-off-by: Lino Sanfilippo <linosanfili...@gmx.de>
---
drivers/net/ethernet/stmicro/stmmac/stmmac.h | 1 -
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 28 +++++------------------
2 files changed, 6 insertions(+), 23 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 4d2a759..7e69b11 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -64,7 +64,6 @@ struct stmmac_priv {
dma_addr_t dma_tx_phy;
int tx_coalesce;
int hwts_tx_en;
- spinlock_t tx_lock;
bool tx_path_in_lpi_mode;
struct timer_list txtimer;
bool tso;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index caf069a..db46ec4 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1307,7 +1307,7 @@ static void stmmac_tx_clean(struct stmmac_priv *priv)
unsigned int bytes_compl = 0, pkts_compl = 0;
unsigned int entry = priv->dirty_tx;
- spin_lock(&priv->tx_lock);
+ netif_tx_lock(priv->dev);
priv->xstats.tx_clean++;
@@ -1378,22 +1378,17 @@ static void stmmac_tx_clean(struct stmmac_priv *priv)
netdev_completed_queue(priv->dev, pkts_compl, bytes_compl);
if (unlikely(netif_queue_stopped(priv->dev) &&
- stmmac_tx_avail(priv) > STMMAC_TX_THRESH)) {
- netif_tx_lock(priv->dev);
- if (netif_queue_stopped(priv->dev) &&
- stmmac_tx_avail(priv) > STMMAC_TX_THRESH) {
- if (netif_msg_tx_done(priv))
- pr_debug("%s: restart transmit\n", __func__);
- netif_wake_queue(priv->dev);
- }
- netif_tx_unlock(priv->dev);
+ stmmac_tx_avail(priv) > STMMAC_TX_THRESH)) {
+ if (netif_msg_tx_done(priv))
+ pr_debug("%s: restart transmit\n", __func__);
+ netif_wake_queue(priv->dev);
}
if ((priv->eee_enabled) && (!priv->tx_path_in_lpi_mode)) {
stmmac_enable_eee_mode(priv);
mod_timer(&priv->eee_ctrl_timer, STMMAC_LPI_T(eee_timer));
}
- spin_unlock(&priv->tx_lock);
+ netif_tx_unlock(priv->dev);
}
static inline void stmmac_enable_dma_irq(struct stmmac_priv *priv)
@@ -1998,8 +1993,6 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb,
struct net_device *dev)
u8 proto_hdr_len;
int i;
- spin_lock(&priv->tx_lock);
-
/* Compute header lengths */
proto_hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
@@ -2011,7 +2004,6 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb,
struct net_device *dev)
/* This is a hard error, log it. */
pr_err("%s: Tx Ring full when queue awake\n", __func__);
}
- spin_unlock(&priv->tx_lock);
return NETDEV_TX_BUSY;
}
@@ -2146,11 +2138,9 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb,
struct net_device *dev)
priv->hw->dma->set_tx_tail_ptr(priv->ioaddr, priv->tx_tail_addr,
STMMAC_CHAN0);
- spin_unlock(&priv->tx_lock);
return NETDEV_TX_OK;
dma_map_err:
- spin_unlock(&priv->tx_lock);
dev_err(priv->device, "Tx dma map failed\n");
dev_kfree_skb(skb);
priv->dev->stats.tx_dropped++;
@@ -2182,10 +2172,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb,
struct net_device *dev)
return stmmac_tso_xmit(skb, dev);
}
- spin_lock(&priv->tx_lock);
-
if (unlikely(stmmac_tx_avail(priv) < nfrags + 1)) {
- spin_unlock(&priv->tx_lock);
if (!netif_queue_stopped(dev)) {
netif_stop_queue(dev);
/* This is a hard error, log it. */
@@ -2357,11 +2344,9 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb,
struct net_device *dev)
priv->hw->dma->set_tx_tail_ptr(priv->ioaddr, priv->tx_tail_addr,
STMMAC_CHAN0);
- spin_unlock(&priv->tx_lock);
return NETDEV_TX_OK;
dma_map_err:
- spin_unlock(&priv->tx_lock);
dev_err(priv->device, "Tx dma map failed\n");
dev_kfree_skb(skb);
priv->dev->stats.tx_dropped++;
@@ -3347,7 +3332,6 @@ int stmmac_dvr_probe(struct device *device,
netif_napi_add(ndev, &priv->napi, stmmac_poll, 64);
spin_lock_init(&priv->lock);
- spin_lock_init(&priv->tx_lock);
ret = register_netdev(ndev);
if (ret) {
--
1.9.1
