mac80211: fix do_stop handling while suspended

When a device is unplugged while suspended, mac80211 is
de-initialized and all interfaces are removed while no
state is actually present in the driver. This can cause
warnings and driver confusion.

Fix this by reordering the do_stop code to not call the
driver when it is suspended, i.e. when there's no state
in the driver anyway.

The previous patches removed a few corner cases in ROC
and virtual monitor interfaces so that now this is safe
to do and no state should be left over.

Reported-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 49 insertions, 25 deletions

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index d0d5f20f1ec4..8c9419595bc8 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -739,8 +739,6 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
                                  sdata->dev->addr_len);
                 spin_unlock_bh(&local->filter_lock);
                 netif_addr_unlock_bh(sdata->dev);
-
-                ieee80211_configure_filter(local);
         }
 
         del_timer_sync(&local->dynamic_ps_timer);
@@ -751,6 +749,7 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
         cancel_delayed_work_sync(&sdata->dfs_cac_timer_work);
 
         if (sdata->wdev.cac_started) {
+                WARN_ON(local->suspended);
                 mutex_lock(&local->iflist_mtx);
                 ieee80211_vif_release_channel(sdata);
                 mutex_unlock(&local->iflist_mtx);
@@ -801,14 +800,9 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
                 if (local->monitors == 0) {
                         local->hw.conf.flags &= ~IEEE80211_CONF_MONITOR;
                         hw_reconf_flags |= IEEE80211_CONF_CHANGE_MONITOR;
-                        ieee80211_del_virtual_monitor(local);
                 }
 
                 ieee80211_adjust_monitor_flags(sdata, -1);
-                ieee80211_configure_filter(local);
-                mutex_lock(&local->mtx);
-                ieee80211_recalc_idle(local);
-                mutex_unlock(&local->mtx);
                 break;
         case NL80211_IFTYPE_P2P_DEVICE:
                 /* relies on synchronize_rcu() below */
@@ -838,27 +832,10 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
                 /* fall through */
         case NL80211_IFTYPE_AP:
                 skb_queue_purge(&sdata->skb_queue);
-
-                if (going_down)
-                        drv_remove_interface(local, sdata);
         }
 
         sdata->bss = NULL;
 
-        ieee80211_recalc_ps(local, -1);
-
-        if (local->open_count == 0) {
-                ieee80211_clear_tx_pending(local);
-                ieee80211_stop_device(local);
-
-                /* no reconfiguring after stop! */
-                hw_reconf_flags = 0;
-        }
-
-        /* do after stop to avoid reconfiguring when we stop anyway */
-        if (hw_reconf_flags)
-                ieee80211_hw_config(local, hw_reconf_flags);
-
         spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
         for (i = 0; i < IEEE80211_MAX_QUEUES; i++) {
                 skb_queue_walk_safe(&local->pending[i], skb, tmp) {
@@ -871,7 +848,54 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
         }
         spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
 
-        if (local->monitors == local->open_count && local->monitors > 0)
+        if (local->open_count == 0)
+                ieee80211_clear_tx_pending(local);
+
+        /*
+         * If the interface goes down while suspended, presumably because
+         * the device was unplugged and that happens before our resume,
+         * then the driver is already unconfigured and the remainder of
+         * this function isn't needed.
+         * XXX: what about WoWLAN? If the device has software state, e.g.
+         *      memory allocated, it might expect teardown commands from
+         *      mac80211 here?
+         */
+        if (local->suspended) {
+                WARN_ON(local->wowlan);
+                WARN_ON(rtnl_dereference(local->monitor_sdata));
+                return;
+        }
+
+        switch (sdata->vif.type) {
+        case NL80211_IFTYPE_AP_VLAN:
+                break;
+        case NL80211_IFTYPE_MONITOR:
+                if (local->monitors == 0)
+                        ieee80211_del_virtual_monitor(local);
+
+                mutex_lock(&local->mtx);
+                ieee80211_recalc_idle(local);
+                mutex_unlock(&local->mtx);
+                break;
+        default:
+                if (going_down)
+                        drv_remove_interface(local, sdata);
+        }
+
+        ieee80211_recalc_ps(local, -1);
+
+        if (local->open_count == 0) {
+                ieee80211_stop_device(local);
+
+                /* no reconfiguring after stop! */
+                return;
+        }
+
+        /* do after stop to avoid reconfiguring when we stop anyway */
+        ieee80211_configure_filter(local);
+        ieee80211_hw_config(local, hw_reconf_flags);
+
+        if (local->monitors == local->open_count)
                 ieee80211_add_virtual_monitor(local);
 }