This is mainly for switchdev and DSA later: To ensure that we switch
to inactive before destroying a bridge interface. A switchdev/DSA driver
might have allocated resources after we switched to an enabled multicast
active state. This gives switchdev/DSA drivers a chance to free these
resources again when we destroy the bridge (later).

Putting it into the ndo_stop / bridge interface down part instead of the
ndo_uninit / bridge destroy part though for a better semantic match. If
the bridge interface is down / stopped then it is also inactive.

No functional change for the fast/data path.

Signed-off-by: Linus Lüssing <linus.luess...@c0d3.blue>
---
 include/uapi/linux/if_link.h |  8 ++++----
 net/bridge/br_device.c       |  3 +++
 net/bridge/br_multicast.c    | 26 ++++++++++++++++++++++----
 3 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index ef686ea17afe..76d15a07344d 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -746,14 +746,14 @@ enum in6_addr_gen_mode {
  * @IFLA_BR_MCAST_ACTIVE_V4
  *   Bridge IPv4 mcast active state, read only.
  *
- *   1 if *IFLA_BR_MCAST_SNOOPING* is enabled and an IGMP querier is present,
- *   0 otherwise.
+ *   1 if *IFLA_BR_MCAST_SNOOPING* is enabled, an IGMP querier is present
+ *   and the bridge interface is up, 0 otherwise.
  *
  * @IFLA_BR_MCAST_ACTIVE_V6
  *   Bridge IPv6 mcast active state, read only.
  *
- *   1 if *IFLA_BR_MCAST_SNOOPING* is enabled and an MLD querier is present,
- *   0 otherwise.
+ *   1 if *IFLA_BR_MCAST_SNOOPING* is enabled, an MLD querier is present
+ *   and the bridge interface is up, 0 otherwise.
  */
 enum {
        IFLA_BR_UNSPEC,
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 3cdf1c17108b..efb5d35c2dd4 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -168,7 +168,10 @@ static int br_dev_open(struct net_device *dev)
        netdev_update_features(dev);
        netif_start_queue(dev);
        br_stp_enable_bridge(br);
+
+       spin_lock_bh(&br->multicast_lock);
        br_multicast_open(br);
+       spin_unlock_bh(&br->multicast_lock);
 
        if (br_opt_get(br, BROPT_MULTICAST_ENABLED))
                br_multicast_join_snoopers(br);
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 53720337a1e3..09e23e4d8b74 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1145,6 +1145,7 @@ static void br_ip6_multicast_update_active(struct 
net_bridge_mcast *brmctx,
  *
  * The multicast active state is set, per protocol family, if:
  *
+ * - the bridge interface is up
  * - multicast snooping is enabled
  * - an IGMP/MLD querier is present
  * - for own IPv6 MLD querier: an IPv6 address is configured on the bridge
@@ -1160,6 +1161,9 @@ static void br_multicast_update_active(struct 
net_bridge_mcast *brmctx)
 
        lockdep_assert_held_once(&brmctx->br->multicast_lock);
 
+       if (!netif_running(brmctx->br->dev))
+               force_inactive = true;
+
        if (!br_opt_get(brmctx->br, BROPT_MULTICAST_ENABLED))
                force_inactive = true;
 
@@ -4379,6 +4383,9 @@ static void __br_multicast_open(struct net_bridge_mcast 
*brmctx)
 #if IS_ENABLED(CONFIG_IPV6)
        __br_multicast_open_query(brmctx->br, &brmctx->ip6_own_query);
 #endif
+
+       /* bridge interface is up, maybe set multicast state to active */
+       br_multicast_update_active(brmctx);
 }
 
 void br_multicast_open(struct net_bridge *br)
@@ -4417,6 +4424,11 @@ static void __br_multicast_stop(struct net_bridge_mcast 
*brmctx)
        timer_delete_sync(&brmctx->ip6_other_query.delay_timer);
        timer_delete_sync(&brmctx->ip6_own_query.timer);
 #endif
+
+       spin_lock_bh(&brmctx->br->multicast_lock);
+       /* bridge interface is down, set multicast state to inactive */
+       br_multicast_update_active(brmctx);
+       spin_unlock_bh(&brmctx->br->multicast_lock);
 }
 
 void br_multicast_update_vlan_mcast_ctx(struct net_bridge_vlan *v, u8 state)
@@ -4469,10 +4481,13 @@ void br_multicast_toggle_one_vlan(struct 
net_bridge_vlan *vlan, bool on)
                br_multicast_update_active(&vlan->br_mcast_ctx);
                spin_unlock_bh(&br->multicast_lock);
 
-               if (on)
+               if (on) {
+                       spin_lock_bh(&br->multicast_lock);
                        __br_multicast_open(&vlan->br_mcast_ctx);
-               else
+                       spin_unlock_bh(&br->multicast_lock);
+               } else {
                        __br_multicast_stop(&vlan->br_mcast_ctx);
+               }
        } else {
                struct net_bridge_mcast *brmctx;
 
@@ -4534,10 +4549,13 @@ int br_multicast_toggle_vlan_snooping(struct net_bridge 
*br, bool on,
        br_opt_toggle(br, BROPT_MCAST_VLAN_SNOOPING_ENABLED, on);
 
        /* disable/enable non-vlan mcast contexts based on vlan snooping */
-       if (on)
+       if (on) {
                __br_multicast_stop(&br->multicast_ctx);
-       else
+       } else {
+               spin_lock_bh(&br->multicast_lock);
                __br_multicast_open(&br->multicast_ctx);
+               spin_unlock_bh(&br->multicast_lock);
+       }
        list_for_each_entry(p, &br->port_list, list) {
                if (on)
                        br_multicast_disable_port_ctx(&p->multicast_ctx);
-- 
2.50.1


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