1 files changed, 45 insertions, 11 deletions

diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
index bba9733b5119..584a6b3f6542 100644
--- a/drivers/net/ethernet/socionext/netsec.c
+++ b/drivers/net/ethernet/socionext/netsec.c
@@ -656,8 +656,13 @@ static int netsec_process_tx(struct netsec_priv *priv, int budget)
                 budget -= new;
         } while (new);
 
-        if (done && netif_queue_stopped(ndev))
+        if (done && netif_queue_stopped(ndev)) {
+                /* Make sure we update the value, anyone stopping the queue
+                 * after this will read the proper consumer idx
+                 */
+                smp_wmb();
                 netif_wake_queue(ndev);
+        }
 
         return done;
 }
@@ -877,6 +882,41 @@ static void netsec_set_tx_de(struct netsec_priv *priv,
         dring->head = (dring->head + 1) % DESC_NUM;
 }
 
+static int netsec_desc_used(struct netsec_desc_ring *dring)
+{
+        int used;
+
+        if (dring->head >= dring->tail)
+                used = dring->head - dring->tail;
+        else
+                used = dring->head + DESC_NUM - dring->tail;
+
+        return used;
+}
+
+static int netsec_check_stop_tx(struct netsec_priv *priv, int used)
+{
+        struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_TX];
+
+        /* keep tail from touching the queue */
+        if (DESC_NUM - used < 2) {
+                netif_stop_queue(priv->ndev);
+
+                /* Make sure we read the updated value in case
+                 * descriptors got freed
+                 */
+                smp_rmb();
+
+                used = netsec_desc_used(dring);
+                if (DESC_NUM - used < 2)
+                        return NETDEV_TX_BUSY;
+
+                netif_wake_queue(priv->ndev);
+        }
+
+        return 0;
+}
+
 static netdev_tx_t netsec_netdev_start_xmit(struct sk_buff *skb,
                                             struct net_device *ndev)
 {
@@ -887,16 +927,10 @@ static netdev_tx_t netsec_netdev_start_xmit(struct sk_buff *skb,
         u16 tso_seg_len = 0;
         int filled;
 
-        /* differentiate between full/emtpy ring */
-        if (dring->head >= dring->tail)
-                filled = dring->head - dring->tail;
-        else
-                filled = dring->head + DESC_NUM - dring->tail;
-
-        if (DESC_NUM - filled < 2) { /* if less than 2 available */
-                netif_err(priv, drv, priv->ndev, "%s: TxQFull!\n", __func__);
-                netif_stop_queue(priv->ndev);
-                dma_wmb();
+        filled = netsec_desc_used(dring);
+        if (netsec_check_stop_tx(priv, filled)) {
+                net_warn_ratelimited("%s %s Tx queue full\n",
+                                     dev_name(priv->dev), ndev->name);
                 return NETDEV_TX_BUSY;
         }