| Message ID | 20200908071713.916165-1-nikolay@cumulusnetworks.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net-next] net: bridge: mcast: fix unused br var when lockdep isn't defined | expand |
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 <sfr@canb.auug.org.au> > Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> > --- > 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.
On 8 September 2020 19:00:49 EEST, Jakub Kicinski <kuba@kernel.org> wrote: >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 <sfr@canb.auug.org.au> >> Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> >> --- >> 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. When the local variable's only used for lockdep, I guess. :) Here we don't actually need it at all, alternatively we can just drop it and use mp->br.
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;
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 <sfr@canb.auug.org.au> Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> --- net/bridge/br_multicast.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)