net: bcmgenet: Add software counters to track reallocations

When inserting the TSB, keep track of how many times we had to do
it and if there was a failure in doing so, this helps profile the
driver for possibly incorrect headroom settings.

Signed-off-by: Doug Berger <opendmb@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/genet/bcmgenet.c

@@ -861,6 +861,9 @@ static const struct bcmgenet_stats bcmgenet_gstrings_stats[] = {
 	STAT_GENET_SOFT_MIB("alloc_rx_buff_failed", mib.alloc_rx_buff_failed),
 	STAT_GENET_SOFT_MIB("rx_dma_failed", mib.rx_dma_failed),
 	STAT_GENET_SOFT_MIB("tx_dma_failed", mib.tx_dma_failed),
+	STAT_GENET_SOFT_MIB("tx_realloc_tsb", mib.tx_realloc_tsb),
+	STAT_GENET_SOFT_MIB("tx_realloc_tsb_failed",
+			    mib.tx_realloc_tsb_failed),
 	/* Per TX queues */
 	STAT_GENET_Q(0),
 	STAT_GENET_Q(1),
@@ -1487,6 +1490,7 @@ static void bcmgenet_tx_reclaim_all(struct net_device *dev)
 static struct sk_buff *bcmgenet_put_tx_csum(struct net_device *dev,
 					    struct sk_buff *skb)
 {
+	struct bcmgenet_priv *priv = netdev_priv(dev);
 	struct status_64 *status = NULL;
 	struct sk_buff *new_skb;
 	u16 offset;
@@ -1501,11 +1505,13 @@ static struct sk_buff *bcmgenet_put_tx_csum(struct net_device *dev,
 		new_skb = skb_realloc_headroom(skb, sizeof(*status));
 		if (!new_skb) {
 			dev_kfree_skb_any(skb);
+			priv->mib.tx_realloc_tsb_failed++;
 			dev->stats.tx_dropped++;
 			return NULL;
 		}
 		dev_consume_skb_any(skb);
 		skb = new_skb;
+		priv->mib.tx_realloc_tsb++;
 	}
 
 	skb_push(skb, sizeof(*status));

drivers/net/ethernet/broadcom/genet/bcmgenet.h

@@ -144,6 +144,8 @@ struct bcmgenet_mib_counters {
 	u32	alloc_rx_buff_failed;
 	u32	rx_dma_failed;
 	u32	tx_dma_failed;
+	u32	tx_realloc_tsb;
+	u32	tx_realloc_tsb_failed;
 };
 
 #define UMAC_HD_BKP_CTRL		0x004