openvswitch: Use exact lookup for flow_get and flow_del.
Due to the race condition in userspace, there is chance that two
overlapping megaflows could be installed in datapath. And this
causes userspace unable to delete the less inclusive megaflow flow
even after it timeout, since the flow_del logic will stop at the
first match of masked flow.
This commit fixes the bug by making the kernel flow_del and flow_get
logic check all masks in that case.
Introduced by 03f0d916a (openvswitch: Mega flow implementation).
Signed-off-by: Alex Wang <alexw@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index a863678..9db4bf6 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -889,8 +889,11 @@
}
/* The unmasked key has to be the same for flow updates. */
if (unlikely(!ovs_flow_cmp_unmasked_key(flow, &match))) {
- error = -EEXIST;
- goto err_unlock_ovs;
+ flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
+ if (!flow) {
+ error = -ENOENT;
+ goto err_unlock_ovs;
+ }
}
/* Update actions. */
old_acts = ovsl_dereference(flow->sf_acts);
@@ -981,16 +984,12 @@
goto err_unlock_ovs;
}
/* Check that the flow exists. */
- flow = ovs_flow_tbl_lookup(&dp->table, &key);
+ flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
if (unlikely(!flow)) {
error = -ENOENT;
goto err_unlock_ovs;
}
- /* The unmasked key has to be the same for flow updates. */
- if (unlikely(!ovs_flow_cmp_unmasked_key(flow, &match))) {
- error = -EEXIST;
- goto err_unlock_ovs;
- }
+
/* Update actions, if present. */
if (likely(acts)) {
old_acts = ovsl_dereference(flow->sf_acts);
@@ -1063,8 +1062,8 @@
goto unlock;
}
- flow = ovs_flow_tbl_lookup(&dp->table, &key);
- if (!flow || !ovs_flow_cmp_unmasked_key(flow, &match)) {
+ flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
+ if (!flow) {
err = -ENOENT;
goto unlock;
}
@@ -1113,8 +1112,8 @@
goto unlock;
}
- flow = ovs_flow_tbl_lookup(&dp->table, &key);
- if (unlikely(!flow || !ovs_flow_cmp_unmasked_key(flow, &match))) {
+ flow = ovs_flow_tbl_lookup_exact(&dp->table, &match);
+ if (unlikely(!flow)) {
err = -ENOENT;
goto unlock;
}