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authorAmerigo Wang <amwang@redhat.com>2012-08-10 01:24:38 +0000
committerDavid S. Miller <davem@davemloft.net>2012-08-14 14:33:30 -0700
commit38e6bc185d9544dfad1774b3f8902a0b061aea25 (patch)
tree5dc41a28f9dc48095c998dfc0dcf8b970db6e1b5 /net/core
parent47be03a28cc6c80e3aa2b3e8ed6d960ff0c5c0af (diff)
downloadlinux-38e6bc185d9544dfad1774b3f8902a0b061aea25.tar.gz
netpoll: make __netpoll_cleanup non-block
Like the previous patch, slave_disable_netpoll() and __netpoll_cleanup()
may be called with read_lock() held too, so we should make them
non-block, by moving the cleanup and kfree() to call_rcu_bh() callbacks.

Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/netpoll.c42
1 files changed, 32 insertions, 10 deletions
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 37cc854774a4..dc17f1db1479 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -878,6 +878,24 @@ static int __init netpoll_init(void)
 }
 core_initcall(netpoll_init);
 
+static void rcu_cleanup_netpoll_info(struct rcu_head *rcu_head)
+{
+	struct netpoll_info *npinfo =
+			container_of(rcu_head, struct netpoll_info, rcu);
+
+	skb_queue_purge(&npinfo->arp_tx);
+	skb_queue_purge(&npinfo->txq);
+
+	/* we can't call cancel_delayed_work_sync here, as we are in softirq */
+	cancel_delayed_work(&npinfo->tx_work);
+
+	/* clean after last, unfinished work */
+	__skb_queue_purge(&npinfo->txq);
+	/* now cancel it again */
+	cancel_delayed_work(&npinfo->tx_work);
+	kfree(npinfo);
+}
+
 void __netpoll_cleanup(struct netpoll *np)
 {
 	struct netpoll_info *npinfo;
@@ -903,20 +921,24 @@ void __netpoll_cleanup(struct netpoll *np)
 			ops->ndo_netpoll_cleanup(np->dev);
 
 		RCU_INIT_POINTER(np->dev->npinfo, NULL);
+		call_rcu_bh(&npinfo->rcu, rcu_cleanup_netpoll_info);
+	}
+}
+EXPORT_SYMBOL_GPL(__netpoll_cleanup);
 
-		/* avoid racing with NAPI reading npinfo */
-		synchronize_rcu_bh();
+static void rcu_cleanup_netpoll(struct rcu_head *rcu_head)
+{
+	struct netpoll *np = container_of(rcu_head, struct netpoll, rcu);
 
-		skb_queue_purge(&npinfo->arp_tx);
-		skb_queue_purge(&npinfo->txq);
-		cancel_delayed_work_sync(&npinfo->tx_work);
+	__netpoll_cleanup(np);
+	kfree(np);
+}
 
-		/* clean after last, unfinished work */
-		__skb_queue_purge(&npinfo->txq);
-		kfree(npinfo);
-	}
+void __netpoll_free_rcu(struct netpoll *np)
+{
+	call_rcu_bh(&np->rcu, rcu_cleanup_netpoll);
 }
-EXPORT_SYMBOL_GPL(__netpoll_cleanup);
+EXPORT_SYMBOL_GPL(__netpoll_free_rcu);
 
 void netpoll_cleanup(struct netpoll *np)
 {