2 files changed, 64 insertions, 7 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 9496fe5ea6b4..3dd2cb465540 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -4715,6 +4715,33 @@ int cfg80211_check_combinations(struct wiphy *wiphy,
                                 const u8 radar_detect,
                                 const int iftype_num[NUM_NL80211_IFTYPES]);
 
+/**
+ * cfg80211_iter_combinations - iterate over matching combinations
+ *
+ * @wiphy: the wiphy
+ * @num_different_channels: the number of different channels we want
+ *      to use for verification
+ * @radar_detect: a bitmap where each bit corresponds to a channel
+ *      width where radar detection is needed, as in the definition of
+ *      &struct ieee80211_iface_combination.@radar_detect_widths
+ * @iftype_num: array with the numbers of interfaces of each interface
+ *      type.  The index is the interface type as specified in &enum
+ *      nl80211_iftype.
+ * @iter: function to call for each matching combination
+ * @data: pointer to pass to iter function
+ *
+ * This function can be called by the driver to check what possible
+ * combinations it fits in at a given moment, e.g. for channel switching
+ * purposes.
+ */
+int cfg80211_iter_combinations(struct wiphy *wiphy,
+                               const int num_different_channels,
+                               const u8 radar_detect,
+                               const int iftype_num[NUM_NL80211_IFTYPES],
+                               void (*iter)(const struct ieee80211_iface_combination *c,
+                                            void *data),
+                               void *data);
+
 /* Logging, debugging and troubleshooting/diagnostic helpers. */
 
 /* wiphy_printk helpers, similar to dev_printk */
diff --git a/net/wireless/util.c b/net/wireless/util.c
index d032a31828f1..d8b599575a5e 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1263,10 +1263,13 @@ int cfg80211_validate_beacon_int(struct cfg80211_registered_device *rdev,
         return res;
 }
 
-int cfg80211_check_combinations(struct wiphy *wiphy,
-                                const int num_different_channels,
-                                const u8 radar_detect,
-                                const int iftype_num[NUM_NL80211_IFTYPES])
+int cfg80211_iter_combinations(struct wiphy *wiphy,
+                               const int num_different_channels,
+                               const u8 radar_detect,
+                               const int iftype_num[NUM_NL80211_IFTYPES],
+                               void (*iter)(const struct ieee80211_iface_combination *c,
+                                            void *data),
+                               void *data)
 {
         int i, j, iftype;
         int num_interfaces = 0;
@@ -1323,13 +1326,40 @@ int cfg80211_check_combinations(struct wiphy *wiphy,
                 /* This combination covered all interface types and
                  * supported the requested numbers, so we're good.
                  */
-                kfree(limits);
-                return 0;
+
+                (*iter)(c, data);
  cont:
                 kfree(limits);
         }
 
-        return -EBUSY;
+        return 0;
+}
+EXPORT_SYMBOL(cfg80211_iter_combinations);
+
+static void
+cfg80211_iter_sum_ifcombs(const struct ieee80211_iface_combination *c,
+                          void *data)
+{
+        int *num = data;
+        (*num)++;
+}
+
+int cfg80211_check_combinations(struct wiphy *wiphy,
+                                const int num_different_channels,
+                                const u8 radar_detect,
+                                const int iftype_num[NUM_NL80211_IFTYPES])
+{
+        int err, num = 0;
+
+        err = cfg80211_iter_combinations(wiphy, num_different_channels,
+                                         radar_detect, iftype_num,
+                                         cfg80211_iter_sum_ifcombs, &num);
+        if (err)
+                return err;
+        if (num == 0)
+                return -EBUSY;
+
+        return 0;
 }
 EXPORT_SYMBOL(cfg80211_check_combinations);