mac80211: atomically check whether STA exists already
When a STA structure is added, it is often checked whether it
already exists before adding it. This, however, isn't done
atomically so there is a race condition that could lead to two
STA structures being added with the same MAC address. This
patch changes sta_info_add() to return an ERR_PTR in case
of failure and adds the failure mode -EEXIST when the STA
already exists.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Luis Carlos Cobo <luisca@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index f7e65fa..7b5be30 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -239,8 +239,8 @@
struct sta_info * sta_info_get(struct ieee80211_local *local, u8 *addr);
void sta_info_put(struct sta_info *sta);
-struct sta_info * sta_info_add(struct ieee80211_local *local,
- struct net_device *dev, u8 *addr, gfp_t gfp);
+struct sta_info *sta_info_add(struct ieee80211_local *local,
+ struct net_device *dev, u8 *addr, gfp_t gfp);
void sta_info_remove(struct sta_info *sta);
void sta_info_free(struct sta_info *sta);
void sta_info_init(struct ieee80211_local *local);