net: bcmgenet: fix dev->stats.tx_bytes accounting

1. Add bytes_compl local variable to __bcmgenet_tx_reclaim() to collect
   transmitted bytes. dev->stats updates can then be moved outside the
   while-loop. bytes_compl is also needed for future BQL support.
2. When bcmgenet device uses Tx checksum offload, each transmitted skb
   gets an extra 64-byte header prepended to it. Before this header is
   prepended to the skb, we need to save the skb "wire" length in
   GENET_CB(skb)->bytes_sent, so that proper Tx bytes accounting can
   be done in __bcmgenet_tx_reclaim().
3. skb->len covers the entire length of skb, whether it is linear or
   fragmented. Thus, when we clean the fragments, do not increase
   transmitted bytes.

Fixes: 1c1008c793fa ("net: bcmgenet: add main driver file")
Signed-off-by: Petri Gynther <pgynther@google.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
index 6746fd0..c1c7c0e 100644 (file)
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -1171,6 +1171,7 @@ static unsigned int __bcmgenet_tx_reclaim(struct net_device *dev,
        struct enet_cb *tx_cb_ptr;
        struct netdev_queue *txq;
        unsigned int pkts_compl = 0;
+       unsigned int bytes_compl = 0;
        unsigned int c_index;
        unsigned int txbds_ready;
        unsigned int txbds_processed = 0;
@@ -1193,16 +1194,13 @@ static unsigned int __bcmgenet_tx_reclaim(struct net_device *dev,
                tx_cb_ptr = &priv->tx_cbs[ring->clean_ptr];
                if (tx_cb_ptr->skb) {
                        pkts_compl++;
-                       dev->stats.tx_packets++;
-                       dev->stats.tx_bytes += tx_cb_ptr->skb->len;
+                       bytes_compl += GENET_CB(tx_cb_ptr->skb)->bytes_sent;
                        dma_unmap_single(&dev->dev,
                                         dma_unmap_addr(tx_cb_ptr, dma_addr),
                                         dma_unmap_len(tx_cb_ptr, dma_len),
                                         DMA_TO_DEVICE);
                        bcmgenet_free_cb(tx_cb_ptr);
                } else if (dma_unmap_addr(tx_cb_ptr, dma_addr)) {
-                       dev->stats.tx_bytes +=
-                               dma_unmap_len(tx_cb_ptr, dma_len);
                        dma_unmap_page(&dev->dev,
                                       dma_unmap_addr(tx_cb_ptr, dma_addr),
                                       dma_unmap_len(tx_cb_ptr, dma_len),
@@ -1220,6 +1218,9 @@ static unsigned int __bcmgenet_tx_reclaim(struct net_device *dev,
        ring->free_bds += txbds_processed;
        ring->c_index = (ring->c_index + txbds_processed) & DMA_C_INDEX_MASK;
 
+       dev->stats.tx_packets += pkts_compl;
+       dev->stats.tx_bytes += bytes_compl;
+
        if (ring->free_bds > (MAX_SKB_FRAGS + 1)) {
                txq = netdev_get_tx_queue(dev, ring->queue);
                if (netif_tx_queue_stopped(txq))
@@ -1464,6 +1465,11 @@ static netdev_tx_t bcmgenet_xmit(struct sk_buff *skb, struct net_device *dev)
                goto out;
        }
 
+       /* Retain how many bytes will be sent on the wire, without TSB inserted
+        * by transmit checksum offload
+        */
+       GENET_CB(skb)->bytes_sent = skb->len;
+
        /* set the SKB transmit checksum */
        if (priv->desc_64b_en) {
                skb = bcmgenet_put_tx_csum(dev, skb);

diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.h b/drivers/net/ethernet/broadcom/genet/bcmgenet.h
index 9673675..1e2dc34 100644 (file)
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.h
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.h
@@ -531,6 +531,12 @@ struct bcmgenet_hw_params {
        u32             flags;
 };
 
+struct bcmgenet_skb_cb {
+       unsigned int bytes_sent;        /* bytes on the wire (no TSB) */
+};
+
+#define GENET_CB(skb)  ((struct bcmgenet_skb_cb *)((skb)->cb))
+
 struct bcmgenet_tx_ring {
        spinlock_t      lock;           /* ring lock */
        struct napi_struct napi;        /* NAPI per tx queue */