openvswitch: Make 100 percents packets sampled when sampling rate is 1.

When sampling rate is 1, the sampling probability is UINT32_MAX. The packet
should be sampled even the prandom32() generate the number of UINT32_MAX.
And none packet need be sampled when the probability is 0.

Signed-off-by: Wenyu Zhang <wenyuz@vmware.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index cf04c2f8b32a..a0ac410e9570 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -669,9 +669,12 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
 
         for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
                  a = nla_next(a, &rem)) {
+                u32 probability;
+
                 switch (nla_type(a)) {
                 case OVS_SAMPLE_ATTR_PROBABILITY:
-                        if (prandom_u32() >= nla_get_u32(a))
+                        probability = nla_get_u32(a);
+                        if (!probability || prandom_u32() > probability)
                                 return 0;
                         break;