On Tue, 8 Sep 2020 10:17:13 +0300 Nikolay Aleksandrov wrote:
> Stephen reported the following warning:
> net/bridge/br_multicast.c: In function 'br_multicast_find_port':
> net/bridge/br_multicast.c:1818:21: warning: unused variable 'br'
> [-Wunused-variable]
> 1818 | struct net_bridge *br = mp->br;
> | ^~
>
> It happens due to bridge's mlock_dereference() when lockdep isn't defined.
> Silence the warning by annotating the variable as __maybe_unused.
>
> Fixes: 0436862e417e ("net: bridge: mcast: support for IGMPv3/MLDv2
> ALLOW_NEW_SOURCES report")
> Reported-by: Stephen Rothwell <[email protected]>
> Signed-off-by: Nikolay Aleksandrov <[email protected]>
> ---
> net/bridge/br_multicast.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
> index b83f11228948..33adf44ef7ec 100644
> --- a/net/bridge/br_multicast.c
> +++ b/net/bridge/br_multicast.c
> @@ -1814,8 +1814,8 @@ br_multicast_find_port(struct net_bridge_mdb_entry *mp,
> struct net_bridge_port *p,
> const unsigned char *src)
> {
> + struct net_bridge *br __maybe_unused = mp->br;
> struct net_bridge_port_group *pg;
> - struct net_bridge *br = mp->br;
>
> for (pg = mlock_dereference(mp->ports, br);
> pg;
That's a lazy fix :( Is everyone using lockdep annotations going to
sprinkle __maybe_unused throughout the code? Macros should also always
evaluate their arguments.
