net: rename dsa_realloc_skb to skb_ensure_writable_head_tail

Rename dsa_realloc_skb to skb_ensure_writable_head_tail and move it to
skbuff.c to use it as helper.
Signed-off-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@oss.nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/skbuff.h

@@ -4007,6 +4007,7 @@ struct sk_buff *skb_segment_list(struct sk_buff *skb, netdev_features_t features
 				 unsigned int offset);
 struct sk_buff *skb_vlan_untag(struct sk_buff *skb);
 int skb_ensure_writable(struct sk_buff *skb, unsigned int write_len);
+int skb_ensure_writable_head_tail(struct sk_buff *skb, struct net_device *dev);
 int __skb_vlan_pop(struct sk_buff *skb, u16 *vlan_tci);
 int skb_vlan_pop(struct sk_buff *skb);
 int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);

net/core/skbuff.c

@@ -5995,6 +5995,31 @@ int skb_ensure_writable(struct sk_buff *skb, unsigned int write_len)
 }
 EXPORT_SYMBOL(skb_ensure_writable);
 
+int skb_ensure_writable_head_tail(struct sk_buff *skb, struct net_device *dev)
+{
+	int needed_headroom = dev->needed_headroom;
+	int needed_tailroom = dev->needed_tailroom;
+
+	/* For tail taggers, we need to pad short frames ourselves, to ensure
+	 * that the tail tag does not fail at its role of being at the end of
+	 * the packet, once the conduit interface pads the frame. Account for
+	 * that pad length here, and pad later.
+	 */
+	if (unlikely(needed_tailroom && skb->len < ETH_ZLEN))
+		needed_tailroom += ETH_ZLEN - skb->len;
+	/* skb_headroom() returns unsigned int... */
+	needed_headroom = max_t(int, needed_headroom - skb_headroom(skb), 0);
+	needed_tailroom = max_t(int, needed_tailroom - skb_tailroom(skb), 0);
+
+	if (likely(!needed_headroom && !needed_tailroom && !skb_cloned(skb)))
+		/* No reallocation needed, yay! */
+		return 0;
+
+	return pskb_expand_head(skb, needed_headroom, needed_tailroom,
+				GFP_ATOMIC);
+}
+EXPORT_SYMBOL(skb_ensure_writable_head_tail);
+
 /* remove VLAN header from packet and update csum accordingly.
  * expects a non skb_vlan_tag_present skb with a vlan tag payload
  */

net/dsa/user.c

@@ -920,30 +920,6 @@ netdev_tx_t dsa_enqueue_skb(struct sk_buff *skb, struct net_device *dev)
 }
 EXPORT_SYMBOL_GPL(dsa_enqueue_skb);
 
-static int dsa_realloc_skb(struct sk_buff *skb, struct net_device *dev)
-{
-	int needed_headroom = dev->needed_headroom;
-	int needed_tailroom = dev->needed_tailroom;
-
-	/* For tail taggers, we need to pad short frames ourselves, to ensure
-	 * that the tail tag does not fail at its role of being at the end of
-	 * the packet, once the conduit interface pads the frame. Account for
-	 * that pad length here, and pad later.
-	 */
-	if (unlikely(needed_tailroom && skb->len < ETH_ZLEN))
-		needed_tailroom += ETH_ZLEN - skb->len;
-	/* skb_headroom() returns unsigned int... */
-	needed_headroom = max_t(int, needed_headroom - skb_headroom(skb), 0);
-	needed_tailroom = max_t(int, needed_tailroom - skb_tailroom(skb), 0);
-
-	if (likely(!needed_headroom && !needed_tailroom && !skb_cloned(skb)))
-		/* No reallocation needed, yay! */
-		return 0;
-
-	return pskb_expand_head(skb, needed_headroom, needed_tailroom,
-				GFP_ATOMIC);
-}
-
 static netdev_tx_t dsa_user_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct dsa_user_priv *p = netdev_priv(dev);
@@ -956,13 +932,14 @@ static netdev_tx_t dsa_user_xmit(struct sk_buff *skb, struct net_device *dev)
 	/* Handle tx timestamp if any */
 	dsa_skb_tx_timestamp(p, skb);
 
-	if (dsa_realloc_skb(skb, dev)) {
+	if (skb_ensure_writable_head_tail(skb, dev)) {
 		dev_kfree_skb_any(skb);
 		return NETDEV_TX_OK;
 	}
 
 	/* needed_tailroom should still be 'warm' in the cache line from
-	 * dsa_realloc_skb(), which has also ensured that padding is safe.
+	 * skb_ensure_writable_head_tail(), which has also ensured that
+	 * padding is safe.
 	 */
 	if (dev->needed_tailroom)
 		eth_skb_pad(skb);