[ Upstream commit e4823fbd22 ]
Add suffix ULL to constant 80000 in order to avoid a potential integer
overflow and give the compiler complete information about the proper
arithmetic to use. Notice that this constant is used in a context that
expects an expression of type u64.
The current cast to u64 effectively applies to the whole expression
as an argument of type u64 to be passed to div64_u64, but it does
not prevent it from being evaluated using 32-bit arithmetic instead
of 64-bit arithmetic.
Also, once the expression is properly evaluated using 64-bit arithmentic,
there is no need for the parentheses and the external cast to u64.
Addresses-Coverity-ID: 1357588 ("Unintentional integer overflow")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Average RTT could become zero. This happened in real life at least twice.
This patch treats zero as 1us.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Lawrence Brakmo <Brakmo@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Most TCP congestion controls are using identical logic to undo
cwnd except BBR. This patch consolidates these similar functions
to the one used currently by Reno and others.
Suggested-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The TCP New Vegas congestion control was exporting an internal
function tcpnv_get_info which is not used by any other in tree
kernel code. Make it static.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
TCP-NV (New Vegas) is a major update to TCP-Vegas.
An earlier version of NV was presented at 2010's LPC.
It is a delayed based congestion avoidance for the
data center. This version has been tested within a
10G rack where the HW RTTs are 20-50us and with
1 to 400 flows.
A description of TCP-NV, including implementation
details as well as experimental results, can be found at:
http://www.brakmo.org/networking/tcp-nv/TCPNV.html
Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Gustavo A. R. Silva