diff options
authorIlpo Järvinen <ilpo.jarvinen@helsinki.fi>2007-10-07 23:43:10 -0700
committerDavid S. Miller <davem@davemloft.net>2007-10-07 23:43:10 -0700
commit48611c47d09023d9356e78550d1cadb8d61da9c8 (patch)
parentDriver core: fix SYSF_DEPRECATED breakage for nested classdevs (diff)
[TCP]: Fix fastpath_cnt_hint when GSO skb is partially ACKed
When only GSO skb was partially ACKed, no hints are reset, therefore fastpath_cnt_hint must be tweaked too or else it can corrupt fackets_out. The corruption to occur, one must have non-trivial ACK/SACK sequence, so this bug is not very often that harmful. There's a fackets_out state reset in TCP because fackets_out is known to be inaccurate and that fixes the issue eventually anyway. In case there was also at least one skb that got fully ACKed, the fastpath_skb_hint is set to NULL which causes a recount for fastpath_cnt_hint (the old value won't be accessed anymore), thus it can safely be decremented without additional checking. Reported by Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
1 files changed, 3 insertions, 0 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index bbad2cdb74b7..f893e90061eb 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2420,6 +2420,9 @@ static int tcp_tso_acked(struct sock *sk, struct sk_buff *skb,
__u32 dval = min(tp->fackets_out, packets_acked);
tp->fackets_out -= dval;
+ /* hint's skb might be NULL but we don't need to care */
+ tp->fastpath_cnt_hint -= min_t(u32, packets_acked,
+ tp->fastpath_cnt_hint);
tp->packets_out -= packets_acked;
BUG_ON(tcp_skb_pcount(skb) == 0);