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, 3 insertions, 2 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 1e20b64e646c..1c9bf8b5c30a 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1512,13 +1512,14 @@ alloc_new_skb:
                                 err = -EMSGSIZE;
                                 goto error;
                         }
-                        if (getfrag(from, skb_frag_address(frag)+frag->size,
+                        if (getfrag(from,
+                                    skb_frag_address(frag) + skb_frag_size(frag),
                                     offset, copy, skb->len, skb) < 0) {
                                 err = -EFAULT;
                                 goto error;
                         }
                         sk->sk_sndmsg_off += copy;
-                        frag->size += copy;
+                        skb_frag_size_add(frag, copy);
                         skb->len += copy;
                         skb->data_len += copy;
                         skb->truesize += copy;