From f936bb42aeb94a069bec7c9e04100d199c372956 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 28 Sep 2021 16:10:49 +0200 Subject: [PATCH] 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: 67b746f94ff39 ("net: bridge: mcast: make sure querier port/address updates are consistent") Reported-by: Mike Galbraith Signed-off-by: Thomas Gleixner Signed-off-by: Sebastian Andrzej Siewior Tested-by: Mike Galbraith Acked-by: Nikolay Aleksandrov Link: https://lore.kernel.org/r/20210928141049.593833-1-bigeasy@linutronix.de Signed-off-by: Jakub Kicinski --- net/bridge/br_multicast.c | 6 ++---- net/bridge/br_private.h | 2 +- 2 files changed, 3 insertions(+), 5 deletions(-) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 3523c8c7068f..f3d751105343 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -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, diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index b4cef3a97f12..e8136db44462 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -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 */ -- 2.39.5