Problem is that listener iteration would call this from atomic context
so this locking is not allowed.

One way is to drop locks before calling the helper, but afaics the lock
isn't really needed, all values are fetched via READ_ONCE().
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>