[ovs-dev] [PATCH 1/4] datapath: meter: fix the incorrect calculation of max delta_t

Yi-Hung Wei yihung.wei at gmail.com
Tue Jul 17 00:55:58 UTC 2018


From: zhangliping <zhangliping02 at baidu.com>

Upstream commit:
    commit ddc502dfed600bff0b61d899f70d95b76223fdfc
    Author: zhangliping <zhangliping02 at baidu.com>
    Date:   Fri Mar 9 10:08:50 2018 +0800

    openvswitch: meter: fix the incorrect calculation of max delta_t

    Max delat_t should be the full_bucket/rate instead of the full_bucket.
    Also report EINVAL if the rate is zero.

    Fixes: 96fbc13d7e77 ("openvswitch: Add meter infrastructure")
    Cc: Andy Zhou <azhou at ovn.org>
    Signed-off-by: zhangliping <zhangliping02 at baidu.com>
    Acked-by: Pravin B Shelar <pshelar at ovn.org>
    Signed-off-by: David S. Miller <davem at davemloft.net>

Signed-off-by: Yi-Hung Wei <yihung.wei at gmail.com>
---
 datapath/meter.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/datapath/meter.c b/datapath/meter.c
index f9e8f124b411..1c2ed4626c2a 100644
--- a/datapath/meter.c
+++ b/datapath/meter.c
@@ -252,14 +252,20 @@ static struct dp_meter *dp_meter_create(struct nlattr **a)
 
 		band->type = nla_get_u32(attr[OVS_BAND_ATTR_TYPE]);
 		band->rate = nla_get_u32(attr[OVS_BAND_ATTR_RATE]);
+		if (band->rate == 0) {
+			err = -EINVAL;
+			goto exit_free_meter;
+		}
+
 		band->burst_size = nla_get_u32(attr[OVS_BAND_ATTR_BURST]);
 		/* Figure out max delta_t that is enough to fill any bucket.
 		 * Keep max_delta_t size to the bucket units:
 		 * pkts => 1/1000 packets, kilobits => bits.
+		 *
+		 * Start with a full bucket.
 		 */
-		band_max_delta_t = (band->burst_size + band->rate) * 1000;
-		/* Start with a full bucket. */
-		band->bucket = band_max_delta_t;
+		band->bucket = (band->burst_size + band->rate) * 1000;
+		band_max_delta_t = band->bucket / band->rate;
 		if (band_max_delta_t > meter->max_delta_t)
 			meter->max_delta_t = band_max_delta_t;
 		band++;
-- 
2.7.4



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