cfg80211: don't export ieee80211_get_channel

This patch makes ieee80211_get_channel a static inline defined in
cfg80211's header file which simply calls __ieee80211_get_channel
to avoid symbol clashes with the ieee80211 code.

The problem was pointed out by David Miller, thanks!
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/net/wireless.h

@@ -304,10 +304,22 @@ extern int ieee80211_channel_to_frequency(int chan);
  */
 extern int ieee80211_frequency_to_channel(int freq);
 
-/**
- * ieee80211_get_channel - get channel struct from wiphy for specified frequency
+/*
+ * Name indirection necessary because the ieee80211 code also has
+ * a function named "ieee80211_get_channel", so if you include
+ * cfg80211's header file you get cfg80211's version, if you try
+ * to include both header files you'll (rightfully!) get a symbol
+ * clash.
  */
-extern struct ieee80211_channel *ieee80211_get_channel(struct wiphy *wiphy,
+extern struct ieee80211_channel *__ieee80211_get_channel(struct wiphy *wiphy,
 							 int freq);
 
+/**
+ * ieee80211_get_channel - get channel struct from wiphy for specified frequency
+ */
+static inline struct ieee80211_channel *
+ieee80211_get_channel(struct wiphy *wiphy, int freq)
+{
+	return __ieee80211_get_channel(wiphy, freq);
+}
 #endif /* __NET_WIRELESS_H */

net/wireless/util.c

@@ -33,7 +33,7 @@ int ieee80211_frequency_to_channel(int freq)
 }
 EXPORT_SYMBOL(ieee80211_frequency_to_channel);
 
-struct ieee80211_channel *ieee80211_get_channel(struct wiphy *wiphy,
+struct ieee80211_channel *__ieee80211_get_channel(struct wiphy *wiphy,
 						  int freq)
 {
 	enum ieee80211_band band;
@@ -54,7 +54,7 @@ struct ieee80211_channel *ieee80211_get_channel(struct wiphy *wiphy,
 
 	return NULL;
 }
-EXPORT_SYMBOL(ieee80211_get_channel);
+EXPORT_SYMBOL(__ieee80211_get_channel);
 
 static void set_mandatory_flags_band(struct ieee80211_supported_band *sband,
 				     enum ieee80211_band band)