| Message ID | Pine.LNX.4.64.0905291552240.10088@wrl-59.cs.helsinki.fi |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: "Ilpo Järvinen" <ilpo.jarvinen@helsinki.fi> Date: Fri, 29 May 2009 16:03:45 +0300 (EEST) > Somewhat luckily, I was looking into these parts with very fine > comb because I've made somewhat similar changes on the same > area (conflicts that arose weren't that lucky though). The loop > was very much overengineered recently in commit 915219441d566 > (tcp: Use SKB queue and list helpers instead of doing it > by-hand), while it basically just wants to know if there are > skbs after 'skb'. > > Also it got broken because skb1 = skb->next got translated into > skb1 = skb1->next (though abstracted) improperly. Note that > 'skb1' is pointing to previous sk_buff than skb or NULL if at > head. Two things went wrong: > - We'll kfree 'skb' on the first iteration instead of the > skbuff following 'skb' (it would require required SACK reneging > to recover I think). > - The list head case where 'skb1' is NULL is checked too early > and the loop won't execute whereas it previously did. > > Conclusion, mostly revert the recent changes which makes the > cset very messy looking but using proper accessor in the > previous-like version. > > The effective changes against the original can be viewed with: > git-diff 915219441d566f1da0caa0e262be49b666159e17^ \ > net/ipv4/tcp_input.c | sed -n -e '57,70 p' > > Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Applied, thanks a lot for catching this! -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index ba34a23..2bdb0da 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4481,26 +4481,20 @@ drop: __skb_queue_after(&tp->out_of_order_queue, skb1, skb); /* And clean segments covered by new one as whole. */ - if (skb1 && !skb_queue_is_last(&tp->out_of_order_queue, skb1)) { - struct sk_buff *n; + while (!skb_queue_is_last(&tp->out_of_order_queue, skb)) { + skb1 = skb_queue_next(&tp->out_of_order_queue, skb); - skb1 = skb_queue_next(&tp->out_of_order_queue, skb1); - skb_queue_walk_from_safe(&tp->out_of_order_queue, - skb1, n) { - if (!after(end_seq, TCP_SKB_CB(skb1)->seq)) - break; - if (before(end_seq, - TCP_SKB_CB(skb1)->end_seq)) { - tcp_dsack_extend(sk, - TCP_SKB_CB(skb1)->seq, - end_seq); - break; - } - __skb_unlink(skb1, &tp->out_of_order_queue); + if (!after(end_seq, TCP_SKB_CB(skb1)->seq)) + break; + if (before(end_seq, TCP_SKB_CB(skb1)->end_seq)) { tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq, - TCP_SKB_CB(skb1)->end_seq); - __kfree_skb(skb1); + end_seq); + break; } + __skb_unlink(skb1, &tp->out_of_order_queue); + tcp_dsack_extend(sk, TCP_SKB_CB(skb1)->seq, + TCP_SKB_CB(skb1)->end_seq); + __kfree_skb(skb1); } add_sack:
Somewhat luckily, I was looking into these parts with very fine comb because I've made somewhat similar changes on the same area (conflicts that arose weren't that lucky though). The loop was very much overengineered recently in commit 915219441d566 (tcp: Use SKB queue and list helpers instead of doing it by-hand), while it basically just wants to know if there are skbs after 'skb'. Also it got broken because skb1 = skb->next got translated into skb1 = skb1->next (though abstracted) improperly. Note that 'skb1' is pointing to previous sk_buff than skb or NULL if at head. Two things went wrong: - We'll kfree 'skb' on the first iteration instead of the skbuff following 'skb' (it would require required SACK reneging to recover I think). - The list head case where 'skb1' is NULL is checked too early and the loop won't execute whereas it previously did. Conclusion, mostly revert the recent changes which makes the cset very messy looking but using proper accessor in the previous-like version. The effective changes against the original can be viewed with: git-diff 915219441d566f1da0caa0e262be49b666159e17^ \ net/ipv4/tcp_input.c | sed -n -e '57,70 p' Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> --- net/ipv4/tcp_input.c | 28 +++++++++++----------------- 1 files changed, 11 insertions(+), 17 deletions(-)