From: Johannes Berg <johannes@sipsolutions.net>
Date: Fri, 27 Apr 2007 03:50:35 +0000 (-0700)
Subject: [WIRELESS] cfg80211: Fix locking in wiphy_new.
X-Git-Tag: firefly_0821_release~30278^2~4
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a4d73ee168eeaed3baea86542ad42e1fd7e192d3;p=firefly-linux-kernel-4.4.55.git

[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 532e1e09e028..24a21add0ba6 100644
--- 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);