From 2a8126f92e11b79486fa9e5356e202c57b2f9a90 Mon Sep 17 00:00:00 2001
From: Neil Horman <nhorman@tuxdriver.com>
Date: Mon, 11 Feb 2013 10:25:31 +0000
Subject: [PATCH] --- yaml --- r: 352408 b: refs/heads/master c:
 0790bbb68f9d483348c1d65381f3dd92602bfd05 h: refs/heads/master v: v3

---
 [refs]                   |  2 +-
 trunk/net/core/netpoll.c | 12 ++++++++----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/[refs] b/[refs]
index 80b58bae48d6..2562a4249d4b 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2cde6acd49daca58b96f1fbc697492825511ad31
+refs/heads/master: 0790bbb68f9d483348c1d65381f3dd92602bfd05
diff --git a/trunk/net/core/netpoll.c b/trunk/net/core/netpoll.c
index c536474e2260..bcfd4f4599a5 100644
--- a/trunk/net/core/netpoll.c
+++ b/trunk/net/core/netpoll.c
@@ -206,7 +206,7 @@ static void netpoll_poll_dev(struct net_device *dev)
 	 * the dev_open/close paths use this to block netpoll activity
 	 * while changing device state
 	 */
-	if (!mutex_trylock(&dev->npinfo->dev_lock))
+	if (!mutex_trylock(&ni->dev_lock))
 		return;
 
 	if (!dev || !netif_running(dev))
@@ -221,7 +221,7 @@ static void netpoll_poll_dev(struct net_device *dev)
 
 	poll_napi(dev);
 
-	mutex_unlock(&dev->npinfo->dev_lock);
+	mutex_unlock(&ni->dev_lock);
 
 	if (dev->flags & IFF_SLAVE) {
 		if (ni) {
@@ -1056,7 +1056,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
 				goto free_npinfo;
 		}
 	} else {
-		npinfo = ndev->npinfo;
+		npinfo = rtnl_dereference(ndev->npinfo);
 		atomic_inc(&npinfo->refcnt);
 	}
 
@@ -1236,7 +1236,11 @@ void __netpoll_cleanup(struct netpoll *np)
 	struct netpoll_info *npinfo;
 	unsigned long flags;
 
-	npinfo = np->dev->npinfo;
+	/* rtnl_dereference would be preferable here but
+	 * rcu_cleanup_netpoll path can put us in here safely without
+	 * holding the rtnl, so plain rcu_dereference it is
+	 */
+	npinfo = rtnl_dereference(np->dev->npinfo);
 	if (!npinfo)
 		return;