net: add skb frag size accessors

To ease skb->truesize sanitization, its better to be able to localize
all references to skb frags size.

Define accessors : skb_frag_size() to fetch frag size, and
skb_frag_size_{set|add|sub}() to manipulate it.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 3 deletions

diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c
index b1fe7c35e8d1..bfa9ab93eda5 100644
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -951,13 +951,12 @@ static unsigned long atalk_sum_skb(const struct sk_buff *skb, int offset,
         /* checksum stuff in frags */
         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                 int end;
-
+                const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
                 WARN_ON(start > offset + len);
 
-                end = start + skb_shinfo(skb)->frags[i].size;
+                end = start + skb_frag_size(frag);
                 if ((copy = end - offset) > 0) {
                         u8 *vaddr;
-                        skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 
                         if (copy > len)
                                 copy = len;