[net v2 1/2] netdev-genl: Hold rcu_read_lock in napi_get

[Joe Damato <jdamato@fastly.com>]

Hold rcu_read_lock in netdev_nl_napi_get_doit, which calls napi_by_id
and is required to be called under rcu_read_lock.

Cc: stable@vger.kernel.org
Fixes: 27f91aaf49b3 ("netdev-genl: Add netlink framework functions for napi")
Signed-off-by: Joe Damato <jdamato@fastly.com>
---
 v2:
   - Simplified by removing the helper and calling rcu_read_lock /
     unlock directly instead.

 net/core/netdev-genl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 765ce7c9d73b..0b684410b52d 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -233,6 +233,7 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info)
 		return -ENOMEM;
 
 	rtnl_lock();
+	rcu_read_lock();
 
 	napi = napi_by_id(napi_id);
 	if (napi) {
@@ -242,6 +243,7 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info)
 		err = -ENOENT;
 	}
 
+	rcu_read_unlock();
 	rtnl_unlock();
 
 	if (err)
-- 
2.25.1