[ Upstream commit 4ae2bb81 ]

Accesses to dev->xps_rxqs_map (when using dev->num_tc) should be
protected by the rtnl lock, like we do for netif_set_xps_queue. I didn't
see an actual bug being triggered, but let's be safe here and take the
rtnl lock while accessing the map in sysfs.

Fixes: 8af2c06f ("net-sysfs: Add interface for Rx queue(s) map per Tx queue")
Signed-off-by: NAntoine Tenart <atenart@kernel.org>
Reviewed-by: NAlexander Duyck <alexanderduyck@fb.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>