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authorWen Yang <wenyang@linux.alibaba.com>2020-01-20 13:04:56 +0300
committerDavid S. Miller <davem@davemloft.net>2020-01-21 12:45:49 +0300
commit5b2f1f3070b6447b76174ea8bfb7390dc6253ebd (patch)
tree1c9a026cc81dde4020ca68da9ed68dc0978a2a47 /net/ipv4
parentcb626bf566eb4433318d35681286c494f04fedcc (diff)
downloadlinux-5b2f1f3070b6447b76174ea8bfb7390dc6253ebd.tar.xz
tcp_bbr: improve arithmetic division in bbr_update_bw()
do_div() does a 64-by-32 division. Use div64_long() instead of it if the divisor is long, to avoid truncation to 32-bit. And as a nice side effect also cleans up the function a bit. Signed-off-by: Wen Yang <wenyang@linux.alibaba.com> Cc: Eric Dumazet <edumazet@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp_bbr.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/net/ipv4/tcp_bbr.c b/net/ipv4/tcp_bbr.c
index a6545ef0d27b..6c4d79baff26 100644
--- a/net/ipv4/tcp_bbr.c
+++ b/net/ipv4/tcp_bbr.c
@@ -779,8 +779,7 @@ static void bbr_update_bw(struct sock *sk, const struct rate_sample *rs)
* bandwidth sample. Delivered is in packets and interval_us in uS and
* ratio will be <<1 for most connections. So delivered is first scaled.
*/
- bw = (u64)rs->delivered * BW_UNIT;
- do_div(bw, rs->interval_us);
+ bw = div64_long((u64)rs->delivered * BW_UNIT, rs->interval_us);
/* If this sample is application-limited, it is likely to have a very
* low delivered count that represents application behavior rather than