ipv6: use RCU to walk list of network devices

No longer need read_lock(&dev_base_lock), use RCU instead.
We also can avoid taking references on inet6_dev structs.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 15 deletions

diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c
index 2f00ca83f04..f1c74c8ef9d 100644
--- a/net/ipv6/anycast.c
+++ b/net/ipv6/anycast.c
@@ -431,9 +431,9 @@ static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq)
 	struct net *net = seq_file_net(seq);
 
 	state->idev = NULL;
-	for_each_netdev(net, state->dev) {
+	for_each_netdev_rcu(net, state->dev) {
 		struct inet6_dev *idev;
-		idev = in6_dev_get(state->dev);
+		idev = __in6_dev_get(state->dev);
 		if (!idev)
 			continue;
 		read_lock_bh(&idev->lock);
@@ -443,7 +443,6 @@ static inline struct ifacaddr6 *ac6_get_first(struct seq_file *seq)
 			break;
 		}
 		read_unlock_bh(&idev->lock);
-		in6_dev_put(idev);
 	}
 	return im;
 }
@@ -454,16 +453,15 @@ static struct ifacaddr6 *ac6_get_next(struct seq_file *seq, struct ifacaddr6 *im
 
 	im = im->aca_next;
 	while (!im) {
-		if (likely(state->idev != NULL)) {
+		if (likely(state->idev != NULL))
 			read_unlock_bh(&state->idev->lock);
-			in6_dev_put(state->idev);
-		}
-		state->dev = next_net_device(state->dev);
+
+		state->dev = next_net_device_rcu(state->dev);
 		if (!state->dev) {
 			state->idev = NULL;
 			break;
 		}
-		state->idev = in6_dev_get(state->dev);
+		state->idev = __in6_dev_get(state->dev);
 		if (!state->idev)
 			continue;
 		read_lock_bh(&state->idev->lock);
@@ -482,29 +480,30 @@ static struct ifacaddr6 *ac6_get_idx(struct seq_file *seq, loff_t pos)
 }
 
 static void *ac6_seq_start(struct seq_file *seq, loff_t *pos)
-	__acquires(dev_base_lock)
+	__acquires(RCU)
 {
-	read_lock(&dev_base_lock);
+	rcu_read_lock();
 	return ac6_get_idx(seq, *pos);
 }
 
 static void *ac6_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
-	struct ifacaddr6 *im;
-	im = ac6_get_next(seq, v);
+	struct ifacaddr6 *im = ac6_get_next(seq, v);
+
 	++*pos;
 	return im;
 }
 
 static void ac6_seq_stop(struct seq_file *seq, void *v)
-	__releases(dev_base_lock)
+	__releases(RCU)
 {
 	struct ac6_iter_state *state = ac6_seq_private(seq);
+
 	if (likely(state->idev != NULL)) {
 		read_unlock_bh(&state->idev->lock);
-		in6_dev_put(state->idev);
+		state->idev = NULL;
 	}
-	read_unlock(&dev_base_lock);
+	rcu_read_unlock();
 }
 
 static int ac6_seq_show(struct seq_file *seq, void *v)