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@ovn.org>
Signed-off-by: zhangliping <zhangliping02@baidu.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 3 deletions

diff --git a/net/openvswitch/meter.c b/net/openvswitch/meter.c
index 04b94281a30b..b891a91577f8 100644
--- a/net/openvswitch/meter.c
+++ b/net/openvswitch/meter.c
@@ -242,14 +242,20 @@ 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++;