Re: [PATCH net-next v2 2/6] net: bridge: convert mdb_entry host_joined to a flags field

On 02/06/2026 03:43, Luke Howard wrote:
> Replace the bool host_joined in struct net_bridge_mdb_entry with a u8
> flags field and a BRIDGE_MDBE_F_HOST_JOINED bit.
> 
> Signed-off-by: Luke Howard <[email protected]>
> ---
>   net/bridge/br_input.c     |  2 +-
>   net/bridge/br_mdb.c       | 14 ++++++++------
>   net/bridge/br_multicast.c | 26 ++++++++++++++------------
>   net/bridge/br_private.h   |  4 +++-
>   net/bridge/br_switchdev.c |  2 +-
>   5 files changed, 27 insertions(+), 21 deletions(-)
> 

it's best these new flags to be unsigned long and use test/set_bit for
manipulating them, otherwise kcsan won't be happy

> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
> index 470615675bdc0..5787066b1f4cb 100644
> --- a/net/bridge/br_input.c
> +++ b/net/bridge/br_input.c
> @@ -188,7 +188,7 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
>   		mdst = br_mdb_entry_skb_get(brmctx, skb, vid);
>   		if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
>   		    br_multicast_querier_exists(brmctx, eth_hdr(skb), mdst)) {
> -			if ((mdst && mdst->host_joined) ||
> +			if ((mdst && (mdst->flags & BRIDGE_MDBE_F_HOST_JOINED)) ||
>   			    br_multicast_is_router(brmctx, skb) ||
>   			    br->dev->flags & IFF_ALLMULTI) {
>   				local_rcv = true;
> diff --git a/net/bridge/br_mdb.c b/net/bridge/br_mdb.c
> index 3ddfbd536edb4..b95ca72ec6347 100644
> --- a/net/bridge/br_mdb.c
> +++ b/net/bridge/br_mdb.c
> @@ -344,7 +344,7 @@ static int br_mdb_fill_info(struct sk_buff *skb, struct netlink_callback *cb,
>   			break;
>   		}
>   
> -		if (!s_pidx && mp->host_joined) {
> +		if (!s_pidx && (mp->flags & BRIDGE_MDBE_F_HOST_JOINED)) {
>   			err = __mdb_fill_info(skb, mp, NULL);
>   			if (err) {
>   				nla_nest_cancel(skb, nest2);
> @@ -1053,7 +1053,8 @@ static int br_mdb_add_group(const struct br_mdb_config *cfg,
>   
>   	/* host join */
>   	if (!port) {
> -		if (mp->host_joined && !(cfg->nlflags & NLM_F_REPLACE)) {
> +		if ((mp->flags & BRIDGE_MDBE_F_HOST_JOINED) &&
> +		    !(cfg->nlflags & NLM_F_REPLACE)) {
>   			NL_SET_ERR_MSG_MOD(extack, "Group is already joined by host");
>   			return -EEXIST;
>   		}
> @@ -1381,7 +1382,8 @@ static int __br_mdb_del(const struct br_mdb_config *cfg)
>   		goto unlock;
>   
>   	/* host leave */
> -	if (entry->ifindex == mp->br->dev->ifindex && mp->host_joined) {
> +	if (entry->ifindex == mp->br->dev->ifindex &&
> +	    (mp->flags & BRIDGE_MDBE_F_HOST_JOINED)) {
>   		br_multicast_host_leave(mp, false);
>   		err = 0;
>   		br_mdb_notify(br->dev, mp, NULL, RTM_DELMDB);
> @@ -1619,7 +1621,7 @@ br_mdb_get_reply_alloc(const struct net_bridge_mdb_entry *mp)
>   		     /* MDBA_MDB_ENTRY */
>   		     nla_total_size(0);
>   
> -	if (mp->host_joined)
> +	if (mp->flags & BRIDGE_MDBE_F_HOST_JOINED)
>   		nlmsg_size += rtnl_mdb_nlmsg_pg_size(NULL);
>   
>   	for (pg = mlock_dereference(mp->ports, mp->br); pg;
> @@ -1658,7 +1660,7 @@ static int br_mdb_get_reply_fill(struct sk_buff *skb,
>   		goto cancel;
>   	}
>   
> -	if (mp->host_joined) {
> +	if (mp->flags & BRIDGE_MDBE_F_HOST_JOINED) {
>   		err = __mdb_fill_info(skb, mp, NULL);
>   		if (err)
>   			goto cancel;
> @@ -1702,7 +1704,7 @@ int br_mdb_get(struct net_device *dev, struct nlattr *tb[], u32 portid, u32 seq,
>   	spin_lock_bh(&br->multicast_lock);
>   
>   	mp = br_mdb_ip_get(br, &group);
> -	if (!mp || (!mp->ports && !mp->host_joined)) {
> +	if (!mp || (!mp->ports && !(mp->flags & BRIDGE_MDBE_F_HOST_JOINED))) {
>   		NL_SET_ERR_MSG_MOD(extack, "MDB entry not found");
>   		err = -ENOENT;
>   		goto unlock;
> diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
> index 5d6fdfb43c046..4107bf7bd271f 100644
> --- a/net/bridge/br_multicast.c
> +++ b/net/bridge/br_multicast.c
> @@ -391,13 +391,13 @@ static void br_multicast_sg_host_state(struct net_bridge_mdb_entry *star_mp,
>   
>   	if (WARN_ON(!br_multicast_is_star_g(&star_mp->addr)))
>   		return;
> -	if (!star_mp->host_joined)
> +	if (!(star_mp->flags & BRIDGE_MDBE_F_HOST_JOINED))
>   		return;
>   
>   	sg_mp = br_mdb_ip_get(star_mp->br, &sg->key.addr);
>   	if (!sg_mp)
>   		return;
> -	sg_mp->host_joined = true;
> +	sg_mp->flags |= BRIDGE_MDBE_F_HOST_JOINED;
>   }
>   
>   /* set the host_joined state of all of *,G's S,G entries */
> @@ -425,7 +425,8 @@ static void br_multicast_star_g_host_state(struct net_bridge_mdb_entry *star_mp)
>   			sg_mp = br_mdb_ip_get(br, &sg_ip);
>   			if (!sg_mp)
>   				continue;
> -			sg_mp->host_joined = star_mp->host_joined;
> +			sg_mp->flags &= ~BRIDGE_MDBE_F_HOST_JOINED;
> +			sg_mp->flags |= star_mp->flags & BRIDGE_MDBE_F_HOST_JOINED;
>   		}
>   	}
>   }
> @@ -453,7 +454,7 @@ static void br_multicast_sg_del_exclude_ports(struct net_bridge_mdb_entry *sgmp)
>   	 * we treat it as EXCLUDE {}, so for an S,G it's considered a
>   	 * STAR_EXCLUDE entry and we can safely leave it
>   	 */
> -	sgmp->host_joined = false;
> +	sgmp->flags &= ~BRIDGE_MDBE_F_HOST_JOINED;
>   
>   	for (pp = &sgmp->ports;
>   	     (p = mlock_dereference(*pp, sgmp->br)) != NULL;) {
> @@ -824,7 +825,8 @@ void br_multicast_del_pg(struct net_bridge_mdb_entry *mp,
>   	hlist_add_head(&pg->mcast_gc.gc_node, &br->mcast_gc_list);
>   	queue_work(system_long_wq, &br->mcast_gc_work);
>   
> -	if (!mp->ports && !mp->host_joined && netif_running(br->dev))
> +	if (!mp->ports && !(mp->flags & BRIDGE_MDBE_F_HOST_JOINED) &&
> +	    netif_running(br->dev))
>   		mod_timer(&mp->timer, jiffies);
>   }
>   
> @@ -1470,8 +1472,8 @@ void br_multicast_del_port_group(struct net_bridge_port_group *p)
>   void br_multicast_host_join(const struct net_bridge_mcast *brmctx,
>   			    struct net_bridge_mdb_entry *mp, bool notify)
>   {
> -	if (!mp->host_joined) {
> -		mp->host_joined = true;
> +	if (!(mp->flags & BRIDGE_MDBE_F_HOST_JOINED)) {
> +		mp->flags |= BRIDGE_MDBE_F_HOST_JOINED;
>   		if (br_multicast_is_star_g(&mp->addr))
>   			br_multicast_star_g_host_state(mp);
>   		if (notify)
> @@ -1486,10 +1488,10 @@ void br_multicast_host_join(const struct net_bridge_mcast *brmctx,
>   
>   void br_multicast_host_leave(struct net_bridge_mdb_entry *mp, bool notify)
>   {
> -	if (!mp->host_joined)
> +	if (!(mp->flags & BRIDGE_MDBE_F_HOST_JOINED))
>   		return;
>   
> -	mp->host_joined = false;
> +	mp->flags &= ~BRIDGE_MDBE_F_HOST_JOINED;
>   	if (br_multicast_is_star_g(&mp->addr))
>   		br_multicast_star_g_host_state(mp);
>   	if (notify)
> @@ -3537,7 +3539,7 @@ static void br_ip4_multicast_query(struct net_bridge_mcast *brmctx,
>   
>   	max_delay *= brmctx->multicast_last_member_count;
>   
> -	if (mp->host_joined &&
> +	if ((mp->flags & BRIDGE_MDBE_F_HOST_JOINED) &&
>   	    (timer_pending(&mp->timer) ?
>   	     time_after(mp->timer.expires, now + max_delay) :
>   	     timer_delete_sync_try(&mp->timer) >= 0))
> @@ -3626,7 +3628,7 @@ static int br_ip6_multicast_query(struct net_bridge_mcast *brmctx,
>   		goto out;
>   
>   	max_delay *= brmctx->multicast_last_member_count;
> -	if (mp->host_joined &&
> +	if ((mp->flags & BRIDGE_MDBE_F_HOST_JOINED) &&
>   	    (timer_pending(&mp->timer) ?
>   	     time_after(mp->timer.expires, now + max_delay) :
>   	     timer_delete_sync_try(&mp->timer) >= 0))
> @@ -3722,7 +3724,7 @@ br_multicast_leave_group(struct net_bridge_mcast *brmctx,
>   		     brmctx->multicast_last_member_interval;
>   
>   	if (!pmctx) {
> -		if (mp->host_joined &&
> +		if ((mp->flags & BRIDGE_MDBE_F_HOST_JOINED) &&
>   		    (timer_pending(&mp->timer) ?
>   		     time_after(mp->timer.expires, time) :
>   		     timer_delete_sync_try(&mp->timer) >= 0)) {
> diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
> index 6a2dabd6f4bfb..1e0eefaf50dd1 100644
> --- a/net/bridge/br_private.h
> +++ b/net/bridge/br_private.h
> @@ -373,12 +373,14 @@ struct net_bridge_port_group {
>   	struct rcu_head			rcu;
>   };
>   
> +#define BRIDGE_MDBE_F_HOST_JOINED	BIT(0)
> +
>   struct net_bridge_mdb_entry {
>   	struct rhash_head		rhnode;
>   	struct net_bridge		*br;
>   	struct net_bridge_port_group __rcu *ports;
>   	struct br_ip			addr;
> -	bool				host_joined;
> +	u8				flags;
>   
>   	struct timer_list		timer;
>   	struct hlist_node		mdb_node;
> diff --git a/net/bridge/br_switchdev.c b/net/bridge/br_switchdev.c
> index c46d8e49ce990..39535f1a6b8ce 100644
> --- a/net/bridge/br_switchdev.c
> +++ b/net/bridge/br_switchdev.c
> @@ -741,7 +741,7 @@ br_switchdev_mdb_replay(struct net_device *br_dev, struct net_device *dev,
>   		struct net_bridge_port_group __rcu * const *pp;
>   		const struct net_bridge_port_group *p;
>   
> -		if (mp->host_joined) {
> +		if (mp->flags & BRIDGE_MDBE_F_HOST_JOINED) {
>   			err = br_switchdev_mdb_queue_one(&mdb_list, dev, action,
>   							 SWITCHDEV_OBJ_ID_HOST_MDB,
>   							 mp, NULL, br_dev);
>