[PATCH v1 net-next 5/7] neighbour: Convert RTM_GETNEIGH to RCU.

[Kuniyuki Iwashima <kuniyu@amazon.com>]

Only __dev_get_by_index() is the RTNL dependant in neigh_get().

Let's replace it with dev_get_by_index_rcu() and convert RTM_GETNEIGH
to RCU.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
---
 net/core/neighbour.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 58a6821dae3d..698999398747 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -2948,6 +2948,8 @@ static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 	if (!skb)
 		return -ENOBUFS;
 
+	rcu_read_lock();
+
 	tbl = neigh_find_table(ndm->ndm_family);
 	if (!tbl) {
 		NL_SET_ERR_MSG(extack, "Unsupported family in header for neighbor get request");
@@ -2964,7 +2966,7 @@ static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 	dst = nla_data(tb[NDA_DST]);
 
 	if (ndm->ndm_ifindex) {
-		dev = __dev_get_by_index(net, ndm->ndm_ifindex);
+		dev = dev_get_by_index_rcu(net, ndm->ndm_ifindex);
 		if (!dev) {
 			NL_SET_ERR_MSG(extack, "Unknown device ifindex");
 			err = -ENODEV;
@@ -2999,8 +3001,11 @@ static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 			goto err;
 	}
 
+	rcu_read_unlock();
+
 	return rtnl_unicast(skb, net, pid);
 err:
+	rcu_read_unlock();
 	kfree_skb(skb);
 	return err;
 }
@@ -3800,7 +3805,7 @@ static const struct rtnl_msg_handler neigh_rtnl_msg_handlers[] __initconst = {
 	{.msgtype = RTM_NEWNEIGH, .doit = neigh_add},
 	{.msgtype = RTM_DELNEIGH, .doit = neigh_delete},
 	{.msgtype = RTM_GETNEIGH, .doit = neigh_get, .dumpit = neigh_dump_info,
-	 .flags = RTNL_FLAG_DUMP_UNLOCKED},
+	 .flags = RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED},
 	{.msgtype = RTM_GETNEIGHTBL, .dumpit = neightbl_dump_info},
 	{.msgtype = RTM_SETNEIGHTBL, .doit = neightbl_set},
 };
-- 
2.49.0