Commit f936bb42 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Jakub Kicinski
Browse files

net: bridge: mcast: Associate the seqcount with its protecting lock. 



The sequence count bridge_mcast_querier::seq is protected by
net_bridge::multicast_lock but seqcount_init() does not associate the
seqcount with the lock. This leads to a warning on PREEMPT_RT because
preemption is still enabled.

Let seqcount_init() associate the seqcount with lock that protects the
write section. Remove lockdep_assert_held_once() because lockdep already checks
whether the associated lock is held.

Fixes: 67b746f9 ("net: bridge: mcast: make sure querier port/address updates are consistent")
Reported-by: default avatarMike Galbraith <efault@gmx.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Tested-by: default avatarMike Galbraith <efault@gmx.de>
Acked-by: default avatarNikolay Aleksandrov <nikolay@nvidia.com>
Link: https://lore.kernel.org/r/20210928141049.593833-1-bigeasy@linutronix.de


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 9e28cfea

net/bridge/br_multicast.c

+2 −4
Original line number Diff line number Diff line
@@ -1677,8 +1677,6 @@ static void br_multicast_update_querier(struct net_bridge_mcast *brmctx, 
					int ifindex,

					struct br_ip *saddr)

{

	lockdep_assert_held_once(&brmctx->br->multicast_lock);



	write_seqcount_begin(&querier->seq);

	querier->port_ifidx = ifindex;

	memcpy(&querier->addr, saddr, sizeof(*saddr));
@@ -3867,13 +3865,13 @@ void br_multicast_ctx_init(struct net_bridge *br, 


	brmctx->ip4_other_query.delay_time = 0;

	brmctx->ip4_querier.port_ifidx = 0;

	seqcount_init(&brmctx->ip4_querier.seq);

	seqcount_spinlock_init(&brmctx->ip4_querier.seq, &br->multicast_lock);

	brmctx->multicast_igmp_version = 2;

#if IS_ENABLED(CONFIG_IPV6)

	brmctx->multicast_mld_version = 1;

	brmctx->ip6_other_query.delay_time = 0;

	brmctx->ip6_querier.port_ifidx = 0;

	seqcount_init(&brmctx->ip6_querier.seq);

	seqcount_spinlock_init(&brmctx->ip6_querier.seq, &br->multicast_lock);

#endif



	timer_setup(&brmctx->ip4_mc_router_timer,

net/bridge/br_private.h

+1 −1
Original line number Diff line number Diff line
@@ -82,7 +82,7 @@ struct bridge_mcast_other_query { 
struct bridge_mcast_querier {

	struct br_ip addr;

	int port_ifidx;

	seqcount_t seq;

	seqcount_spinlock_t seq;

};



/* IGMP/MLD statistics */