[PATCH RFC net] net: bcmgenet: fix leaking and racing timeout handler

[justin.chen@broadcom.com]

From: Justin Chen <justin.chen@broadcom.com>

The bcmgenet_timeout handler tries to take down all tx queues when
a single queue times out. This is over zealous and causes many race
conditions with queues that are still chugging along. Instead lets
only restart the timed out queue.

While reclaiming the tx queue we fast forward the write pointer to
drop any data in flight. These dropped frames are not added back
to the pool of free bds. We also need to tell the netdev that we
are dropping said data.

Signed-off-by: Justin Chen <justin.chen@broadcom.com>
---
 .../net/ethernet/broadcom/genet/bcmgenet.c    | 24 +++++++++----------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index 482a31e7b72b..f69cf490445c 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -1985,6 +1985,7 @@ static unsigned int bcmgenet_tx_reclaim(struct net_device *dev,
 		drop = (ring->prod_index - ring->c_index) & DMA_C_INDEX_MASK;
 		released += drop;
 		ring->prod_index = ring->c_index & DMA_C_INDEX_MASK;
+		ring->free_bds += drop;
 		while (drop--) {
 			cb_ptr = bcmgenet_put_txcb(priv, ring);
 			skb = cb_ptr->skb;
@@ -1996,6 +1997,7 @@ static unsigned int bcmgenet_tx_reclaim(struct net_device *dev,
 		}
 		if (skb)
 			dev_consume_skb_any(skb);
+		netdev_tx_reset_queue(netdev_get_tx_queue(dev, ring->index));
 		bcmgenet_tdma_ring_writel(priv, ring->index,
 					  ring->prod_index, TDMA_PROD_INDEX);
 		wr_ptr = ring->write_ptr * WORDS_PER_BD(priv);
@@ -3475,27 +3477,23 @@ static void bcmgenet_dump_tx_queue(struct bcmgenet_tx_ring *ring)
 static void bcmgenet_timeout(struct net_device *dev, unsigned int txqueue)
 {
 	struct bcmgenet_priv *priv = netdev_priv(dev);
-	u32 int1_enable = 0;
-	unsigned int q;
+	struct bcmgenet_tx_ring *ring = &priv->tx_rings[txqueue];
+	struct netdev_queue *txq = netdev_get_tx_queue(dev, txqueue);
 
 	netif_dbg(priv, tx_err, dev, "bcmgenet_timeout\n");
 
-	for (q = 0; q <= priv->hw_params->tx_queues; q++)
-		bcmgenet_dump_tx_queue(&priv->tx_rings[q]);
-
-	bcmgenet_tx_reclaim_all(dev);
+	bcmgenet_dump_tx_queue(ring);
 
-	for (q = 0; q <= priv->hw_params->tx_queues; q++)
-		int1_enable |= (1 << q);
+	bcmgenet_tx_reclaim(dev, ring, true);
 
-	/* Re-enable TX interrupts if disabled */
-	bcmgenet_intrl2_1_writel(priv, int1_enable, INTRL2_CPU_MASK_CLEAR);
+	/* Re-enable the TX interrupt for this ring */
+	bcmgenet_intrl2_1_writel(priv, 1 << txqueue, INTRL2_CPU_MASK_CLEAR);
 
-	netif_trans_update(dev);
+	txq_trans_cond_update(txq);
 
-	BCMGENET_STATS64_INC((&priv->tx_rings[txqueue].stats64), errors);
+	BCMGENET_STATS64_INC((&ring->stats64), errors);
 
-	netif_tx_wake_all_queues(dev);
+	netif_tx_wake_queue(txq);
 }
 
 #define MAX_MDF_FILTER	17
-- 
2.34.1