cfg80211: allow drivers to iterate over matching combinations

The patch splits cfg80211_check_combinations()
into an iterator function and a simple iteration
user.

This makes it possible for drivers to asses how
many channels can use given iftype setup. This in
turn can be used for future
multi-interface/multi-channel channel switching.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 37 insertions, 7 deletions

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);