netfilter: defrag: remove one redundant atomic ops

Instead of doing one atomic operation per frag, we can factorize them.
Reported from Eric Dumazet.

Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index 6fb8901..bc5b86d 100644 (file)
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -442,7 +442,6 @@ nf_ct_frag6_reasm(struct nf_ct_frag6_queue *fq, struct net_device *dev)
        skb_shinfo(head)->frag_list = head->next;
        skb_reset_transport_header(head);
        skb_push(head, head->data - skb_network_header(head));
-       atomic_sub(head->truesize, &nf_init_frags.mem);
 
        for (fp=head->next; fp; fp = fp->next) {
                head->data_len += fp->len;
@@ -452,8 +451,8 @@ nf_ct_frag6_reasm(struct nf_ct_frag6_queue *fq, struct net_device *dev)
                else if (head->ip_summed == CHECKSUM_COMPLETE)
                        head->csum = csum_add(head->csum, fp->csum);
                head->truesize += fp->truesize;
-               atomic_sub(fp->truesize, &nf_init_frags.mem);
        }
+       atomic_sub(head->truesize, &nf_init_frags.mem);
 
        head->next = NULL;
        head->dev = dev;