net: dsa: Refactor transmit path to eliminate duplication

All tagging protocols do the same thing: increment device statistics,
make room for the tag to be inserted, create the tag, invoke the parent
network device transmit function.

In order to prepare for adding netpoll support, which requires the tag
creation, but not using the parent network device transmit function, do
some little refactoring which eliminates duplication between the 4
tagging protocols supported.

We need to return a sk_buff pointer back to the caller because the tag
specific transmit function may have to reallocate the original skb (e.g:
tag_trailer.c) and this is the one we should be transmitting, not the
original sk_buff we were passed.

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

1 files changed, 3 insertions, 12 deletions

diff --git a/net/dsa/tag_brcm.c b/net/dsa/tag_brcm.c
index 83d3572cdb20..e2aadb73111d 100644
--- a/net/dsa/tag_brcm.c
+++ b/net/dsa/tag_brcm.c
@@ -58,14 +58,11 @@
 #define BRCM_EG_TC_MASK		0x7
 #define BRCM_EG_PID_MASK	0x1f
 
-static netdev_tx_t brcm_tag_xmit(struct sk_buff *skb, struct net_device *dev)
+static struct sk_buff *brcm_tag_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
 	u8 *brcm_tag;
 
-	dev->stats.tx_packets++;
-	dev->stats.tx_bytes += skb->len;
-
 	if (skb_cow_head(skb, BRCM_TAG_LEN) < 0)
 		goto out_free;
 
@@ -87,17 +84,11 @@ static netdev_tx_t brcm_tag_xmit(struct sk_buff *skb, struct net_device *dev)
 		brcm_tag[2] = BRCM_IG_DSTMAP2_MASK;
 	brcm_tag[3] = (1 << p->port) & BRCM_IG_DSTMAP1_MASK;
 
-	/* Queue the SKB for transmission on the parent interface, but
-	 * do not modify its EtherType
-	 */
-	skb->dev = p->parent->dst->master_netdev;
-	dev_queue_xmit(skb);
-
-	return NETDEV_TX_OK;
+	return skb;
 
 out_free:
 	kfree_skb(skb);
-	return NETDEV_TX_OK;
+	return NULL;
 }
 
 static int brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev,