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, 5 insertions, 3 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index dde6b576831..ed96c543f1c 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1094,14 +1094,16 @@ static void __pskb_trim_head(struct sk_buff *skb, int len)
         eat = len;
         k = 0;
         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
-                if (skb_shinfo(skb)->frags[i].size <= eat) {
+                int size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
+
+                if (size <= eat) {
                         skb_frag_unref(skb, i);
-                        eat -= skb_shinfo(skb)->frags[i].size;
+                        eat -= size;
                 } else {
                         skb_shinfo(skb)->frags[k] = skb_shinfo(skb)->frags[i];
                         if (eat) {
                                 skb_shinfo(skb)->frags[k].page_offset += eat;
-                                skb_shinfo(skb)->frags[k].size -= eat;
+                                skb_frag_size_sub(&skb_shinfo(skb)->frags[k], eat);
                                 eat = 0;
                         }
                         k++;