Signed-off-by: Jarno Rajahalme <jrajaha...@nicira.com>
---
ofproto/ofproto.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/ofproto/ofproto.c b/ofproto/ofproto.c
index 30b1b97..b8f0e62 100644
--- a/ofproto/ofproto.c
+++ b/ofproto/ofproto.c
@@ -1357,10 +1357,17 @@ ofproto_flush__(struct ofproto *ofproto)
{
struct oftable *table;
+ /* This will flush all datapath flows. */
if (ofproto->ofproto_class->flush) {
ofproto->ofproto_class->flush(ofproto);
}
+ /* XXX: There is a small race window here, where new datapath flows can be
+ * created by upcall handlers based on the existing flow table. We can not
+ * call ofproto class flush while holding 'ofproto_mutex' to prevent this,
+ * as then we could deadlock on syncing with the handler threads waiting on
+ * the same mutex. */
+
ovs_mutex_lock(&ofproto_mutex);
OFPROTO_FOR_EACH_TABLE (table, ofproto) {
struct rule *rule;
@@ -1373,6 +1380,9 @@ ofproto_flush__(struct ofproto *ofproto)
ofproto_rule_delete__(rule, OFPRR_DELETE);
}
}
+ /* XXX: Concurrent handler threads may insert new learned flows based on
+ * learn actions of the now deleted flows right after we release
+ * 'ofproto_mutex'. */
ovs_mutex_unlock(&ofproto_mutex);
}
--
1.7.10.4
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