cfg80211: add wiphy_idx_valid to check for wiphy_idx sanity

This will later be used by others, for now make use of it in
cfg80211_drv_by_wiphy_idx() to return early if an invalid
wiphy_idx has been provided.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 11 insertions, 1 deletions

diff --git a/net/wireless/core.c b/net/wireless/core.c
index 2b3e786ec53f..35d457b2751e 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -42,6 +42,9 @@ cfg80211_drv_by_wiphy_idx(int wiphy_idx)
 {
         struct cfg80211_registered_device *result = NULL, *drv;
 
+        if (!wiphy_idx_valid(wiphy_idx))
+                return NULL;
+
         list_for_each_entry(drv, &cfg80211_drv_list, list) {
                 if (drv->wiphy_idx == wiphy_idx) {
                         result = drv;
@@ -225,7 +228,7 @@ struct wiphy *wiphy_new(struct cfg80211_ops *ops, int sizeof_priv)
 
         drv->wiphy_idx = wiphy_counter++;
 
-        if (unlikely(drv->wiphy_idx < 0)) {
+        if (unlikely(!wiphy_idx_valid(drv->wiphy_idx))) {
                 wiphy_counter--;
                 mutex_unlock(&cfg80211_drv_mutex);
                 /* ugh, wrapped! */
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 178378124800..4f2e0fe38ce3 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -63,6 +63,13 @@ struct cfg80211_registered_device *wiphy_to_dev(struct wiphy *wiphy)
         return container_of(wiphy, struct cfg80211_registered_device, wiphy);
 }
 
+/* Note 0 is valid, hence phy0 */
+static inline
+bool wiphy_idx_valid(int wiphy_idx)
+{
+        return (wiphy_idx >= 0);
+}
+
 extern struct mutex cfg80211_drv_mutex;
 extern struct list_head cfg80211_drv_list;