skb: Add inline helper for getting the skb end offset from head

With the recent changes for how we compute the skb truesize it occurs to me
we are probably going to have a lot of calls to skb_end_pointer -
skb->head.  Instead of running all over the place doing that it would make
more sense to just make it a separate inline skb_end_offset(skb) that way
we can return the correct value without having gcc having to do all the
optimization to cancel out skb->head - skb->head.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 2 insertions, 2 deletions

diff --git a/drivers/atm/ambassador.c b/drivers/atm/ambassador.c
index f8f41e0e8a8c..89b30f32ba68 100644
--- a/drivers/atm/ambassador.c
+++ b/drivers/atm/ambassador.c
@@ -802,7 +802,7 @@ static void fill_rx_pool (amb_dev * dev, unsigned char pool,
     }
     // cast needed as there is no %? for pointer differences
     PRINTD (DBG_SKB, "allocated skb at %p, head %p, area %li",
-            skb, skb->head, (long) (skb_end_pointer(skb) - skb->head));
+            skb, skb->head, (long) skb_end_offset(skb));
     rx.handle = virt_to_bus (skb);
     rx.host_address = cpu_to_be32 (virt_to_bus (skb->data));
     if (rx_give (dev, &rx, pool))
diff --git a/drivers/atm/idt77252.c b/drivers/atm/idt77252.c
index 1c052127548c..8974bd2b961e 100644
--- a/drivers/atm/idt77252.c
+++ b/drivers/atm/idt77252.c
@@ -1258,7 +1258,7 @@ idt77252_rx_raw(struct idt77252_dev *card)
         tail = readl(SAR_REG_RAWCT);
 
         pci_dma_sync_single_for_cpu(card->pcidev, IDT77252_PRV_PADDR(queue),
-                                    skb_end_pointer(queue) - queue->head - 16,
+                                    skb_end_offset(queue) - 16,
                                     PCI_DMA_FROMDEVICE);
 
         while (head != tail) {