[WIRELESS] cfg80211: Fix locking in wiphy_new.

This patch fixes the locking in wiphy new. Ingo Oeser
<netdev@axxeo.de> noticed that locking in the error case was wrong and
also suggested this fix.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/wireless/core.c b/net/wireless/core.c
index 532e1e09e028e3d69e5f4089c76ac0d0e9532e2a..24a21add0ba6dba234a4658ebc2c4702a5c1961e 100644 (file)
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -53,21 +53,25 @@ struct wiphy *wiphy_new(struct cfg80211_ops *ops, int sizeof_priv)
 
        mutex_lock(&cfg80211_drv_mutex);
 
-       if (unlikely(wiphy_counter<0)) {
+       drv->idx = wiphy_counter;
+
+       /* now increase counter for the next device unless
+        * it has wrapped previously */
+       if (wiphy_counter >= 0)
+               wiphy_counter++;
+
+       mutex_unlock(&cfg80211_drv_mutex);
+
+       if (unlikely(drv->idx < 0)) {
                /* ugh, wrapped! */
                kfree(drv);
                return NULL;
        }
-       drv->idx = wiphy_counter;
 
        /* give it a proper name */
        snprintf(drv->wiphy.dev.bus_id, BUS_ID_SIZE,
                 PHY_NAME "%d", drv->idx);
 
-       /* now increase counter for the next time */
-       wiphy_counter++;
-       mutex_unlock(&cfg80211_drv_mutex);
-
        mutex_init(&drv->mtx);
        mutex_init(&drv->devlist_mtx);
        INIT_LIST_HEAD(&drv->netdev_list);