iwlegacy: do not nulify il->vif on reset

This il->vif is dereferenced in different part of iwlegacy code, so do
not nullify it. This should fix random crashes observed in companion
with microcode errors i.e. crash in il3945_config_ap().

Additionally this should address also
WARNING: at drivers/net/wireless/iwlegacy/common.c:4656 il_mac_remove_interface
at least one of the possible reasons of that warning.

Cc: stable@vger.kernel.org
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 12 insertions, 7 deletions

diff --git a/drivers/net/wireless/iwlegacy/3945-mac.c b/drivers/net/wireless/iwlegacy/3945-mac.c
index 0c1209390169..faec40467208 100644
--- a/drivers/net/wireless/iwlegacy/3945-mac.c
+++ b/drivers/net/wireless/iwlegacy/3945-mac.c
@@ -2673,8 +2673,6 @@ il3945_bg_restart(struct work_struct *data)
 
         if (test_and_clear_bit(S_FW_ERROR, &il->status)) {
                 mutex_lock(&il->mutex);
-                /* FIXME: vif can be dereferenced */
-                il->vif = NULL;
                 il->is_open = 0;
                 mutex_unlock(&il->mutex);
                 il3945_down(il);
diff --git a/drivers/net/wireless/iwlegacy/4965-mac.c b/drivers/net/wireless/iwlegacy/4965-mac.c
index 7b54dbb338be..b88bb2734197 100644
--- a/drivers/net/wireless/iwlegacy/4965-mac.c
+++ b/drivers/net/wireless/iwlegacy/4965-mac.c
@@ -5651,8 +5651,6 @@ il4965_bg_restart(struct work_struct *data)
 
         if (test_and_clear_bit(S_FW_ERROR, &il->status)) {
                 mutex_lock(&il->mutex);
-                /* FIXME: do we dereference vif without mutex locked ? */
-                il->vif = NULL;
                 il->is_open = 0;
 
                 __il4965_down(il);
diff --git a/drivers/net/wireless/iwlegacy/common.c b/drivers/net/wireless/iwlegacy/common.c
index e5ac04739bcc..6a692a534ffc 100644
--- a/drivers/net/wireless/iwlegacy/common.c
+++ b/drivers/net/wireless/iwlegacy/common.c
@@ -4508,6 +4508,7 @@ il_mac_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 {
         struct il_priv *il = hw->priv;
         int err;
+        bool reset;
 
         mutex_lock(&il->mutex);
         D_MAC80211("enter: type %d, addr %pM\n", vif->type, vif->addr);
@@ -4518,7 +4519,12 @@ il_mac_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
                 goto out;
         }
 
-        if (il->vif) {
+        /*
+         * We do not support multiple virtual interfaces, but on hardware reset
+         * we have to add the same interface again.
+         */
+        reset = (il->vif == vif);
+        if (il->vif && !reset) {
                 err = -EOPNOTSUPP;
                 goto out;
         }
@@ -4528,8 +4534,11 @@ il_mac_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 
         err = il_set_mode(il);
         if (err) {
-                il->vif = NULL;
-                il->iw_mode = NL80211_IFTYPE_STATION;
+                IL_WARN("Fail to set mode %d\n", vif->type);
+                if (!reset) {
+                        il->vif = NULL;
+                        il->iw_mode = NL80211_IFTYPE_STATION;
+                }
         }
 
 out: