iwlwifi: do not nulify ctx->vif on reset

ctx->vif is dereferenced in different part of iwlwifi code, so do not
nullify it.

This should address at least one of the possible reasons of WARNING at
iwlagn_mac_remove_interface, and perhaps some random crashes when
firmware reset is performed.

Cc: stable@vger.kernel.org
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 9 insertions, 4 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index f1226dbf789d..2a9a16f901c3 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -863,7 +863,6 @@ static void iwl_bg_run_time_calib_work(struct work_struct *work)
 
 void iwlagn_prepare_restart(struct iwl_priv *priv)
 {
-        struct iwl_rxon_context *ctx;
         bool bt_full_concurrent;
         u8 bt_ci_compliance;
         u8 bt_load;
@@ -872,8 +871,6 @@ void iwlagn_prepare_restart(struct iwl_priv *priv)
 
         lockdep_assert_held(&priv->mutex);
 
-        for_each_context(priv, ctx)
-                ctx->vif = NULL;
         priv->is_open = 0;
 
         /*
diff --git a/drivers/net/wireless/iwlwifi/iwl-mac80211.c b/drivers/net/wireless/iwlwifi/iwl-mac80211.c
index b6805f8e9a01..c24a7134a6f9 100644
--- a/drivers/net/wireless/iwlwifi/iwl-mac80211.c
+++ b/drivers/net/wireless/iwlwifi/iwl-mac80211.c
@@ -1244,6 +1244,7 @@ static int iwlagn_mac_add_interface(struct ieee80211_hw *hw,
         struct iwl_rxon_context *tmp, *ctx = NULL;
         int err;
         enum nl80211_iftype viftype = ieee80211_vif_type_p2p(vif);
+        bool reset = false;
 
         IWL_DEBUG_MAC80211(priv, "enter: type %d, addr %pM\n",
                            viftype, vif->addr);
@@ -1265,6 +1266,13 @@ static int iwlagn_mac_add_interface(struct ieee80211_hw *hw,
                         tmp->interface_modes | tmp->exclusive_interface_modes;
 
                 if (tmp->vif) {
+                        /* On reset we need to add the same interface again */
+                        if (tmp->vif == vif) {
+                                reset = true;
+                                ctx = tmp;
+                                break;
+                        }
+
                         /* check if this busy context is exclusive */
                         if (tmp->exclusive_interface_modes &
                                                 BIT(tmp->vif->type)) {
@@ -1291,7 +1299,7 @@ static int iwlagn_mac_add_interface(struct ieee80211_hw *hw,
         ctx->vif = vif;
 
         err = iwl_setup_interface(priv, ctx);
-        if (!err)
+        if (!err || reset)
                 goto out;
 
         ctx->vif = NULL;