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);