From: Jesse Gross <jesse@nicira.com>
Date: Wed, 12 May 2010 20:45:49 +0000 (-0700)
Subject: datapath: Hold rcu_read_lock where we claim to.
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9dca7bd50a93eeb26fb7e47ddb896de22f782e7b;p=openvswitch

datapath: Hold rcu_read_lock where we claim to.

Many of the vport operations require that either RTNL lock or
rcu_read_lock be held.  However, operations from userspace often
hold a different lock so grab rcu_read_lock as well.
---

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 67c422ad..a083274b 100644
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -1305,8 +1305,12 @@ static int do_execute(struct datapath *dp, const struct odp_execute *execute)
 		skb->protocol = htons(ETH_P_802_2);
 
 	flow_extract(skb, execute->in_port, &key);
+
+	rcu_read_lock();
 	err = execute_actions(dp, skb, &key, actions->actions,
 			      actions->n_actions, GFP_KERNEL);
+	rcu_read_unlock();
+
 	kfree(actions);
 	return err;
 
diff --git a/datapath/vport.c b/datapath/vport.c
index cc209593..691ab84b 100644
--- a/datapath/vport.c
+++ b/datapath/vport.c
@@ -400,9 +400,12 @@ vport_stats_get(struct odp_vport_stats_req __user *ustats_req)
 		goto out;
 	}
 
-	if (vport->ops->get_stats)
+	if (vport->ops->get_stats) {
+		rcu_read_lock();
 		err = vport->ops->get_stats(vport, &stats_req.stats);
-	else if (vport->ops->flags & VPORT_F_GEN_STATS) {
+		rcu_read_unlock();
+
+	} else if (vport->ops->flags & VPORT_F_GEN_STATS) {
 		int i;
 
 		memset(&stats_req.stats, 0, sizeof(struct odp_vport_stats));
@@ -475,7 +478,9 @@ vport_ether_get(struct odp_vport_ether __user *uvport_ether)
 		goto out;
 	}
 
+	rcu_read_lock();
 	memcpy(vport_ether.ether_addr, vport_get_addr(vport), ETH_ALEN);
+	rcu_read_unlock();
 
 out:
 	vport_unlock();
@@ -632,11 +637,17 @@ vport_locate(const char *name)
 		dump_stack();
 	}
 
+	rcu_read_lock();
+
 	hlist_for_each_entry(vport, node, bucket, hash_node)
 		if (!strcmp(name, vport_get_name(vport)))
-			return vport;
+			goto out;
 
-	return NULL;
+	vport = NULL;
+
+out:
+	rcu_read_unlock();
+	return vport;
 }
 
 static void