rtnetlink: do not depend on RTNL in rtnl_xdp_prog_skb()

dev->xdp_prog is protected by RCU, we can lift RTNL requirement
from rtnl_xdp_prog_skb().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index dfdd08006faec016c24c0a3ff3bba4f47e9357c3..41eb8bca530587074611d85e02b0a083ad367ed4 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1477,13 +1477,15 @@ static int rtnl_fill_link_ifmap(struct sk_buff *skb,
 static u32 rtnl_xdp_prog_skb(struct net_device *dev)
 {
        const struct bpf_prog *generic_xdp_prog;
+       u32 res = 0;
 
-       ASSERT_RTNL();
+       rcu_read_lock();
+       generic_xdp_prog = rcu_dereference(dev->xdp_prog);
+       if (generic_xdp_prog)
+               res = generic_xdp_prog->aux->id;
+       rcu_read_unlock();
 
-       generic_xdp_prog = rtnl_dereference(dev->xdp_prog);
-       if (!generic_xdp_prog)
-               return 0;
-       return generic_xdp_prog->aux->id;
+       return res;
 }
 
 static u32 rtnl_xdp_prog_drv(struct net_device *dev)