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>

diff --git a/drivers/atm/ambassador.c b/drivers/atm/ambassador.c
index f8f41e0e8a8c45a4cb595a6380fdb3fec9bad11d..89b30f32ba68b4f1e5cd58fc5911a95213abf163 100644 (file)
--- 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 1c052127548c4f18575e835591e65b7b2a7e8196..8974bd2b961e605b3b03c9c52e8dbedc897fb485 100644 (file)
--- 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) {

diff --git a/drivers/net/wimax/i2400m/usb-rx.c b/drivers/net/wimax/i2400m/usb-rx.c
index e3257681e3605a3b9659527e892b16e779718600..b78ee676e1029fc21d5ed189b118f43b62aac631 100644 (file)
--- a/drivers/net/wimax/i2400m/usb-rx.c
+++ b/drivers/net/wimax/i2400m/usb-rx.c
@@ -277,7 +277,7 @@ retry:
                d_printf(1, dev, "RX: size changed to %d, received %d, "
                         "copied %d, capacity %ld\n",
                         rx_size, read_size, rx_skb->len,
-                        (long) (skb_end_pointer(new_skb) - new_skb->head));
+                        (long) skb_end_offset(new_skb));
                goto retry;
        }
                /* In most cases, it happens due to the hardware scheduling a

diff --git a/drivers/staging/octeon/ethernet-tx.c b/drivers/staging/octeon/ethernet-tx.c
index 56d74dc2fbd5b5f3b7122371554d51647b5effb9..418ed03d0887bf1f44ee98680728541539aeec42 100644 (file)
--- a/drivers/staging/octeon/ethernet-tx.c
+++ b/drivers/staging/octeon/ethernet-tx.c
@@ -344,7 +344,7 @@ int cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev)
        }
        if (unlikely
            (skb->truesize !=
-            sizeof(*skb) + skb_end_pointer(skb) - skb->head)) {
+            sizeof(*skb) + skb_end_offset(skb))) {
                /*
                   printk("TX buffer truesize has been changed\n");
                 */

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 37f539129d8964f92595bc3c2a06ca3eebda5ad7..91ad5e227d1d1d528eb1e3ab93ebe84cb652ed9f 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -645,11 +645,21 @@ static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
 {
        return skb->head + skb->end;
 }
+
+static inline unsigned int skb_end_offset(const struct sk_buff *skb)
+{
+       return skb->end;
+}
 #else
 static inline unsigned char *skb_end_pointer(const struct sk_buff *skb)
 {
        return skb->end;
 }
+
+static inline unsigned int skb_end_offset(const struct sk_buff *skb)
+{
+       return skb->end - skb->head;
+}
 #endif
 
 /* Internal */
@@ -2558,7 +2568,7 @@ static inline bool skb_is_recycleable(const struct sk_buff *skb, int skb_size)
                return false;
 
        skb_size = SKB_DATA_ALIGN(skb_size + NET_SKB_PAD);
-       if (skb_end_pointer(skb) - skb->head < skb_size)
+       if (skb_end_offset(skb) < skb_size)
                return false;
 
        if (skb_shared(skb) || skb_cloned(skb))

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 17e4b1e1bf2c9f6b2d218fe3cf4906c95eb3fbea..2c35da818ef9bcf0cdcbd9c1e0edb33423457c53 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -829,7 +829,7 @@ static void copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
 {
        int headerlen = skb_headroom(skb);
-       unsigned int size = (skb_end_pointer(skb) - skb->head) + skb->data_len;
+       unsigned int size = skb_end_offset(skb) + skb->data_len;
        struct sk_buff *n = alloc_skb(size, gfp_mask);
 
        if (!n)
@@ -930,7 +930,7 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
 {
        int i;
        u8 *data;
-       int size = nhead + (skb_end_pointer(skb) - skb->head) + ntail;
+       int size = nhead + skb_end_offset(skb) + ntail;
        long off;
 
        BUG_ON(nhead < 0);
@@ -2727,14 +2727,13 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
                        if (unlikely(!nskb))
                                goto err;
 
-                       hsize = skb_end_pointer(nskb) - nskb->head;
+                       hsize = skb_end_offset(nskb);
                        if (skb_cow_head(nskb, doffset + headroom)) {
                                kfree_skb(nskb);
                                goto err;
                        }
 
-                       nskb->truesize += skb_end_pointer(nskb) - nskb->head -
-                                         hsize;
+                       nskb->truesize += skb_end_offset(nskb) - hsize;
                        skb_release_head_state(nskb);
                        __skb_push(nskb, doffset);
                } else {
@@ -2883,7 +2882,8 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
                skb_frag_size_sub(frag, offset);
 
                /* all fragments truesize : remove (head size + sk_buff) */
-               delta_truesize = skb->truesize - SKB_TRUESIZE(skb_end_pointer(skb) - skb->head);
+               delta_truesize = skb->truesize -
+                                SKB_TRUESIZE(skb_end_offset(skb));
 
                skb->truesize -= skb->data_len;
                skb->len -= skb->data_len;