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| author | Christoph Paasch <christoph.paasch@uclouvain.be> | 2014-07-29 13:40:57 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-08-14 09:51:48 +0800 |
| commit | 4fe35cff3da65dff640e33f48e1e5986c4094e5f (patch) | |
| tree | 12ac18da95181e54aed750ca9831a6cbef89432c | |
| parent | c2b2fb6a9434abe5b84c8c563a0c12459b0ec65f (diff) | |
| download | lwn-4fe35cff3da65dff640e33f48e1e5986c4094e5f.tar.gz lwn-4fe35cff3da65dff640e33f48e1e5986c4094e5f.zip | |
tcp: Fix integer-overflow in TCP vegas
[ Upstream commit 1f74e613ded11517db90b2bd57e9464d9e0fb161 ]
In vegas we do a multiplication of the cwnd and the rtt. This
may overflow and thus their result is stored in a u64. However, we first
need to cast the cwnd so that actually 64-bit arithmetic is done.
Then, we need to do do_div to allow this to be used on 32-bit arches.
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Doug Leith <doug.leith@nuim.ie>
Fixes: 8d3a564da34e (tcp: tcp_vegas cong avoid fix)
Signed-off-by: Christoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/ipv4/tcp_vegas.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/tcp_vegas.c b/net/ipv4/tcp_vegas.c index 48539fff6357..08c8ab490fe5 100644 --- a/net/ipv4/tcp_vegas.c +++ b/net/ipv4/tcp_vegas.c @@ -219,7 +219,8 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked, * This is: * (actual rate in segments) * baseRTT */ - target_cwnd = tp->snd_cwnd * vegas->baseRTT / rtt; + target_cwnd = (u64)tp->snd_cwnd * vegas->baseRTT; + do_div(target_cwnd, rtt); /* Calculate the difference between the window we had, * and the window we would like to have. This quantity |