2 files changed, 18 insertions, 1 deletions

diff --git a/drivers/net/wireless/rtl8187.h b/drivers/net/wireless/rtl8187.h
index 1b0d750f6623..5a9515c99960 100644
--- a/drivers/net/wireless/rtl8187.h
+++ b/drivers/net/wireless/rtl8187.h
@@ -94,6 +94,10 @@ struct rtl8187_priv {
         const struct rtl818x_rf_ops *rf;
         struct ieee80211_vif *vif;
         int mode;
+        /* The mutex protects the TX loopback state.
+         * Any attempt to set channels concurrently locks the device.
+         */
+        struct mutex conf_mutex;
 
         /* rtl8187 specific */
         struct ieee80211_channel channels[14];
diff --git a/drivers/net/wireless/rtl8187_dev.c b/drivers/net/wireless/rtl8187_dev.c
index 461aa26164c2..57376fb993ed 100644
--- a/drivers/net/wireless/rtl8187_dev.c
+++ b/drivers/net/wireless/rtl8187_dev.c
@@ -728,6 +728,7 @@ static int rtl8187_start(struct ieee80211_hw *dev)
         if (ret)
                 return ret;
 
+        mutex_lock(&priv->conf_mutex);
         if (priv->is_rtl8187b) {
                 reg = RTL818X_RX_CONF_MGMT |
                       RTL818X_RX_CONF_DATA |
@@ -749,6 +750,7 @@ static int rtl8187_start(struct ieee80211_hw *dev)
                                   (7 << 0  /* long retry limit */) |
                                   (7 << 21 /* MAX TX DMA */));
                 rtl8187_init_urbs(dev);
+                mutex_unlock(&priv->conf_mutex);
                 return 0;
         }
 
@@ -792,6 +794,7 @@ static int rtl8187_start(struct ieee80211_hw *dev)
         reg |= RTL818X_CMD_TX_ENABLE;
         reg |= RTL818X_CMD_RX_ENABLE;
         rtl818x_iowrite8(priv, &priv->map->CMD, reg);
+        mutex_unlock(&priv->conf_mutex);
 
         return 0;
 }
@@ -803,6 +806,7 @@ static void rtl8187_stop(struct ieee80211_hw *dev)
         struct sk_buff *skb;
         u32 reg;
 
+        mutex_lock(&priv->conf_mutex);
         rtl818x_iowrite16(priv, &priv->map->INT_MASK, 0);
 
         reg = rtl818x_ioread8(priv, &priv->map->CMD);
@@ -822,7 +826,7 @@ static void rtl8187_stop(struct ieee80211_hw *dev)
                 usb_kill_urb(info->urb);
                 kfree_skb(skb);
         }
-        return;
+        mutex_unlock(&priv->conf_mutex);
 }
 
 static int rtl8187_add_interface(struct ieee80211_hw *dev,
@@ -842,6 +846,7 @@ static int rtl8187_add_interface(struct ieee80211_hw *dev,
                 return -EOPNOTSUPP;
         }
 
+        mutex_lock(&priv->conf_mutex);
         priv->vif = conf->vif;
 
         rtl818x_iowrite8(priv, &priv->map->EEPROM_CMD, RTL818X_EEPROM_CMD_CONFIG);
@@ -850,6 +855,7 @@ static int rtl8187_add_interface(struct ieee80211_hw *dev,
                                  ((u8 *)conf->mac_addr)[i]);
         rtl818x_iowrite8(priv, &priv->map->EEPROM_CMD, RTL818X_EEPROM_CMD_NORMAL);
 
+        mutex_unlock(&priv->conf_mutex);
         return 0;
 }
 
@@ -857,8 +863,10 @@ static void rtl8187_remove_interface(struct ieee80211_hw *dev,
                                      struct ieee80211_if_init_conf *conf)
 {
         struct rtl8187_priv *priv = dev->priv;
+        mutex_lock(&priv->conf_mutex);
         priv->mode = IEEE80211_IF_TYPE_MNTR;
         priv->vif = NULL;
+        mutex_unlock(&priv->conf_mutex);
 }
 
 static int rtl8187_config(struct ieee80211_hw *dev, struct ieee80211_conf *conf)
@@ -866,6 +874,7 @@ static int rtl8187_config(struct ieee80211_hw *dev, struct ieee80211_conf *conf)
         struct rtl8187_priv *priv = dev->priv;
         u32 reg;
 
+        mutex_lock(&priv->conf_mutex);
         reg = rtl818x_ioread32(priv, &priv->map->TX_CONF);
         /* Enable TX loopback on MAC level to avoid TX during channel
          * changes, as this has be seen to causes problems and the
@@ -898,6 +907,7 @@ static int rtl8187_config(struct ieee80211_hw *dev, struct ieee80211_conf *conf)
         rtl818x_iowrite16(priv, &priv->map->ATIMTR_INTERVAL, 100);
         rtl818x_iowrite16(priv, &priv->map->BEACON_INTERVAL, 100);
         rtl818x_iowrite16(priv, &priv->map->BEACON_INTERVAL_TIME, 100);
+        mutex_unlock(&priv->conf_mutex);
         return 0;
 }
 
@@ -909,6 +919,7 @@ static int rtl8187_config_interface(struct ieee80211_hw *dev,
         int i;
         u8 reg;
 
+        mutex_lock(&priv->conf_mutex);
         for (i = 0; i < ETH_ALEN; i++)
                 rtl818x_iowrite8(priv, &priv->map->BSSID[i], conf->bssid[i]);
 
@@ -922,6 +933,7 @@ static int rtl8187_config_interface(struct ieee80211_hw *dev,
                 rtl818x_iowrite8(priv, &priv->map->MSR, reg);
         }
 
+        mutex_unlock(&priv->conf_mutex);
         return 0;
 }
 
@@ -1189,6 +1201,7 @@ static int __devinit rtl8187_probe(struct usb_interface *intf,
                 printk(KERN_ERR "rtl8187: Cannot register device\n");
                 goto err_free_dev;
         }
+        mutex_init(&priv->conf_mutex);
 
         printk(KERN_INFO "%s: hwaddr %s, %s V%d + %s\n",
                wiphy_name(dev->wiphy), print_mac(mac, dev->wiphy->perm_addr),