b43: do not call ieee80211_unregister_hw if we are not registred

this patch fixes kernel Oops on "rmmod b43" if firmware was not loaded:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000088
IP: [<ffffffff8104e988>] drain_workqueue+0x25/0x142
PGD 153ac6067 PUD 153b82067 PMD 0
Oops: 0000 [#1] SMP

Signed-off-by: Oleksij Rempel <bug-track@fisher-privat.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 12 insertions, 7 deletions

diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
index 5a39b226b2e3..acd03a4f9730 100644
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -2437,6 +2437,7 @@ start_ieee80211:
         err = ieee80211_register_hw(wl->hw);
         if (err)
                 goto err_one_core_detach;
+        wl->hw_registred = true;
         b43_leds_register(wl->current_dev);
         goto out;
 
@@ -5299,6 +5300,7 @@ static struct b43_wl *b43_wireless_init(struct b43_bus_dev *dev)
 
         hw->queues = modparam_qos ? B43_QOS_QUEUE_NUM : 1;
         wl->mac80211_initially_registered_queues = hw->queues;
+        wl->hw_registred = false;
         hw->max_rates = 2;
         SET_IEEE80211_DEV(hw, dev->dev);
         if (is_valid_ether_addr(sprom->et1mac))
@@ -5370,12 +5372,15 @@ static void b43_bcma_remove(struct bcma_device *core)
          * as the ieee80211 unreg will destroy the workqueue. */
         cancel_work_sync(&wldev->restart_work);
 
-        /* Restore the queues count before unregistering, because firmware detect
-         * might have modified it. Restoring is important, so the networking
-         * stack can properly free resources. */
-        wl->hw->queues = wl->mac80211_initially_registered_queues;
-        b43_leds_stop(wldev);
-        ieee80211_unregister_hw(wl->hw);
+        B43_WARN_ON(!wl);
+        if (wl->current_dev == wldev && wl->hw_registred) {
+                /* Restore the queues count before unregistering, because firmware detect
+                 * might have modified it. Restoring is important, so the networking
+                 * stack can properly free resources. */
+                wl->hw->queues = wl->mac80211_initially_registered_queues;
+                b43_leds_stop(wldev);
+                ieee80211_unregister_hw(wl->hw);
+        }
 
         b43_one_core_detach(wldev->dev);
 
@@ -5446,7 +5451,7 @@ static void b43_ssb_remove(struct ssb_device *sdev)
         cancel_work_sync(&wldev->restart_work);
 
         B43_WARN_ON(!wl);
-        if (wl->current_dev == wldev) {
+        if (wl->current_dev == wldev && wl->hw_registred) {
                 /* Restore the queues count before unregistering, because firmware detect
                  * might have modified it. Restoring is important, so the networking
                  * stack can properly free resources. */