diff --git a/drivers/net/wireless/zd1211rw/zd_chip.c b/drivers/net/wireless/zd1211rw/zd_chip.c
index e7e92ecc..5841998 100644
--- a/drivers/net/wireless/zd1211rw/zd_chip.c
+++ b/drivers/net/wireless/zd1211rw/zd_chip.c
@@ -42,12 +42,11 @@
 
 void zd_chip_clear(struct zd_chip *chip)
 {
-	mutex_lock(&chip->mutex);
+	ZD_ASSERT(!mutex_is_locked(&chip->mutex));
 	zd_usb_clear(&chip->usb);
 	zd_rf_clear(&chip->rf);
-	mutex_unlock(&chip->mutex);
 	mutex_destroy(&chip->mutex);
-	memset(chip, 0, sizeof(*chip));
+	ZD_MEMCLEAR(chip, sizeof(*chip));
 }
 
 static int scnprint_mac_oui(const u8 *addr, char *buffer, size_t size)
diff --git a/drivers/net/wireless/zd1211rw/zd_def.h b/drivers/net/wireless/zd1211rw/zd_def.h
index 4659068..a13ec72 100644
--- a/drivers/net/wireless/zd1211rw/zd_def.h
+++ b/drivers/net/wireless/zd1211rw/zd_def.h
@@ -45,4 +45,10 @@
 #  define ZD_ASSERT(x) do { } while (0)
 #endif
 
+#ifdef DEBUG
+#  define ZD_MEMCLEAR(pointer, size) memset((pointer), 0xff, (size))
+#else
+#  define ZD_MEMCLEAR(pointer, size) do { } while (0)
+#endif
+
 #endif /* _ZD_DEF_H */
diff --git a/drivers/net/wireless/zd1211rw/zd_mac.c b/drivers/net/wireless/zd1211rw/zd_mac.c
index d6f3e02..0eda534 100644
--- a/drivers/net/wireless/zd1211rw/zd_mac.c
+++ b/drivers/net/wireless/zd1211rw/zd_mac.c
@@ -127,11 +127,9 @@
 
 void zd_mac_clear(struct zd_mac *mac)
 {
-	/* Aquire the lock. */
-	spin_lock(&mac->lock);
-	spin_unlock(&mac->lock);
 	zd_chip_clear(&mac->chip);
-	memset(mac, 0, sizeof(*mac));
+	ZD_ASSERT(!spin_is_locked(&mac->lock));
+	ZD_MEMCLEAR(mac, sizeof(struct zd_mac));
 }
 
 static int reset_mode(struct zd_mac *mac)
diff --git a/drivers/net/wireless/zd1211rw/zd_mac.h b/drivers/net/wireless/zd1211rw/zd_mac.h
index 71e382c..082bcf8 100644
--- a/drivers/net/wireless/zd1211rw/zd_mac.h
+++ b/drivers/net/wireless/zd1211rw/zd_mac.h
@@ -121,9 +121,9 @@
 };
 
 struct zd_mac {
-	struct net_device *netdev;
 	struct zd_chip chip;
 	spinlock_t lock;
+	struct net_device *netdev;
 	/* Unlocked reading possible */
 	struct iw_statistics iw_stats;
 	u8 qual_average;
diff --git a/drivers/net/wireless/zd1211rw/zd_rf.c b/drivers/net/wireless/zd1211rw/zd_rf.c
index ccf639a..f50cff3 100644
--- a/drivers/net/wireless/zd1211rw/zd_rf.c
+++ b/drivers/net/wireless/zd1211rw/zd_rf.c
@@ -56,7 +56,7 @@
 
 void zd_rf_clear(struct zd_rf *rf)
 {
-	memset(rf, 0, sizeof(*rf));
+	ZD_MEMCLEAR(rf, sizeof(*rf));
 }
 
 int zd_rf_init_hw(struct zd_rf *rf, u8 type)
diff --git a/drivers/net/wireless/zd1211rw/zd_usb.c b/drivers/net/wireless/zd1211rw/zd_usb.c
index f721ea5..47489fe 100644
--- a/drivers/net/wireless/zd1211rw/zd_usb.c
+++ b/drivers/net/wireless/zd1211rw/zd_usb.c
@@ -664,7 +664,7 @@
 	usb_submit_urb(urb, GFP_ATOMIC);
 }
 
-struct urb *alloc_urb(struct zd_usb *usb)
+static struct urb *alloc_urb(struct zd_usb *usb)
 {
 	struct usb_device *udev = zd_usb_to_usbdev(usb);
 	struct urb *urb;
@@ -688,7 +688,7 @@
 	return urb;
 }
 
-void free_urb(struct urb *urb)
+static void free_urb(struct urb *urb)
 {
 	if (!urb)
 		return;
@@ -908,7 +908,7 @@
 {
 	usb_set_intfdata(usb->intf, NULL);
 	usb_put_intf(usb->intf);
-	memset(usb, 0, sizeof(*usb));
+	ZD_MEMCLEAR(usb, sizeof(*usb));
 	/* FIXME: usb_interrupt, usb_tx, usb_rx? */
 }
 
@@ -1099,7 +1099,6 @@
 	 */
 	usb_reset_device(interface_to_usbdev(intf));
 
-	/* If somebody still waits on this lock now, this is an error. */
 	zd_netdev_free(netdev);
 	dev_dbg(&intf->dev, "disconnected\n");
 }