From b3130cfce3c81649af2406c4d881566c521fbd1a Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Sat, 11 Jul 2015 01:37:36 +0200 Subject: [PATCH] Revert "ipv4: use skb coalescing in defragmentation" This reverts commit ed1d25054a74ad555b46cbd4a113b2723bedbe6b. There is nothing wrong with coalescing during defragmentation, it reduces truesize overhead and simplifies things for the receiving socket (no fraglist walk needed). However, it also destroys geometry of the original fragments. While that doesn't cause any breakage (we make sure to not exceed largest original size) ip_do_fragment contains a 'fastpath' that takes advantage of a present frag list and results in fragments that (in most cases) match what was received. In case its needed the coalescing could be done later, when we're sure the skb is not forwarded. But discussion during NFWS resulted in 'lets just remove this for now'. Cc: Eric Dumazet Signed-off-by: Florian Westphal Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/ip_fragment.c | 26 ++++++-------------------- 1 file changed, 6 insertions(+), 20 deletions(-) diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index a50dc6d408d11..4d3fffafbe247 100644 --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -522,7 +522,6 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, int len; int ihlen; int err; - int sum_truesize; u8 ecn; ipq_kill(qp); @@ -590,32 +589,19 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev, add_frag_mem_limit(&qp->q, clone->truesize); } + skb_shinfo(head)->frag_list = head->next; skb_push(head, head->data - skb_network_header(head)); - sum_truesize = head->truesize; - for (fp = head->next; fp;) { - bool headstolen; - int delta; - struct sk_buff *next = fp->next; - - sum_truesize += fp->truesize; + for (fp=head->next; fp; fp = fp->next) { + head->data_len += fp->len; + head->len += fp->len; if (head->ip_summed != fp->ip_summed) head->ip_summed = CHECKSUM_NONE; else if (head->ip_summed == CHECKSUM_COMPLETE) head->csum = csum_add(head->csum, fp->csum); - - if (skb_try_coalesce(head, fp, &headstolen, &delta)) { - kfree_skb_partial(fp, headstolen); - } else { - if (!skb_shinfo(head)->frag_list) - skb_shinfo(head)->frag_list = fp; - head->data_len += fp->len; - head->len += fp->len; - head->truesize += fp->truesize; - } - fp = next; + head->truesize += fp->truesize; } - sub_frag_mem_limit(&qp->q, sum_truesize); + sub_frag_mem_limit(&qp->q, head->truesize); head->next = NULL; head->dev = dev; -- 2.39.5