netpoll info leak

After looking harder, Steve noticed that the netpoll
beast leaked a little every time it shutdown for a nap.
Not a big leak, but a nuisance kind of thing.

He took out his refcount duct tape and patched the
leak. It was overkill since there was already other
locking in that area, but it looked clean and wouldn't
attract fleas.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>

1 files changed, 19 insertions, 6 deletions

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 4de62f1f4134..c66df2f45d26 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -658,8 +658,11 @@ int netpoll_setup(struct netpoll *np)
 		npinfo->tries = MAX_RETRIES;
 		spin_lock_init(&npinfo->rx_lock);
 		skb_queue_head_init(&npinfo->arp_tx);
-	} else
+		atomic_set(&npinfo->refcnt, 1);
+	} else {
 		npinfo = ndev->npinfo;
+		atomic_inc(&npinfo->refcnt);
+	}
 
 	if (!ndev->poll_controller) {
 		printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
@@ -766,12 +769,22 @@ void netpoll_cleanup(struct netpoll *np)
 
 	if (np->dev) {
 		npinfo = np->dev->npinfo;
-		if (npinfo && npinfo->rx_np == np) {
-			spin_lock_irqsave(&npinfo->rx_lock, flags);
-			npinfo->rx_np = NULL;
-			npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
-			spin_unlock_irqrestore(&npinfo->rx_lock, flags);
+		if (npinfo) {
+			if (npinfo->rx_np == np) {
+				spin_lock_irqsave(&npinfo->rx_lock, flags);
+				npinfo->rx_np = NULL;
+				npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
+				spin_unlock_irqrestore(&npinfo->rx_lock, flags);
+			}
+
+			np->dev->npinfo = NULL;
+			if (atomic_dec_and_test(&npinfo->refcnt)) {
+				skb_queue_purge(&npinfo->arp_tx);
+
+				kfree(npinfo);
+			}
 		}
+
 		dev_put(np->dev);
 	}