net: bcmgenet: fix TX reclaim accounting for fragments

ffainelli · davem330 · commit 478a010c9235 · 2014-09-22T18:38:40.000-04:00
The GENET driver supports SKB fragments, and succeeds in transmitting them properly, but when reclaiming these transmitted fragments, we will only update the count of free buffer descriptors by 1, even for SKBs with fragments. This leads to the networking stack thinking it has more room than the hardware has when pushing new SKBs, and backing off consequently because we return NETDEV_TX_BUSY. Fix this by accounting for the SKB nr_frags plus one (itself) and update ring->free_bds accordingly with that value for each iteration loop in __bcmgenet_tx_reclaim(). Fixes: 1c1008c ("net: bcmgenet: add main driver file") Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -875,6 +875,7 @@ static void __bcmgenet_tx_reclaim(struct net_device *dev,
 	int last_tx_cn, last_c_index, num_tx_bds;
 	struct enet_cb *tx_cb_ptr;
 	struct netdev_queue *txq;
+	unsigned int bds_compl;
 	unsigned int c_index;
 
 	/* Compute how many buffers are transmitted since last xmit call */
@@ -899,7 +900,9 @@ static void __bcmgenet_tx_reclaim(struct net_device *dev,
 	/* Reclaim transmitted buffers */
 	while (last_tx_cn-- > 0) {
 		tx_cb_ptr = ring->cbs + last_c_index;
+		bds_compl = 0;
 		if (tx_cb_ptr->skb) {
+			bds_compl = skb_shinfo(tx_cb_ptr->skb)->nr_frags + 1;
 			dev->stats.tx_bytes += tx_cb_ptr->skb->len;
 			dma_unmap_single(&dev->dev,
 					 dma_unmap_addr(tx_cb_ptr, dma_addr),
@@ -916,7 +919,7 @@ static void __bcmgenet_tx_reclaim(struct net_device *dev,
 			dma_unmap_addr_set(tx_cb_ptr, dma_addr, 0);
 		}
 		dev->stats.tx_packets++;
-		ring->free_bds += 1;
+		ring->free_bds += bds_compl;
 
 		last_c_index++;
 		last_c_index &= (num_tx_bds - 1);
