--- a/drivers/net/wireless/ath/ath9k/hw.h
+++ b/drivers/net/wireless/ath/ath9k/hw.h
@@ -61,6 +61,8 @@
 
 #define ATH9K_RSSI_BAD			-128
 
+#define ATH9K_NUM_CHANNELS	38
+
 /* Register read/write primitives */
 #define REG_WRITE(_ah, _reg, _val) \
 	ath9k_hw_common(_ah)->ops->write((_ah), (_val), (_reg))
@@ -618,7 +620,7 @@ struct ath_hw {
 	struct ath9k_hw_version hw_version;
 	struct ath9k_ops_config config;
 	struct ath9k_hw_capabilities caps;
-	struct ath9k_channel channels[38];
+	struct ath9k_channel channels[ATH9K_NUM_CHANNELS];
 	struct ath9k_channel *curchan;
 
 	union {
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -482,6 +482,10 @@ static int ath9k_init_channels_rates(str
 {
 	void *channels;
 
+	BUILD_BUG_ON(ARRAY_SIZE(ath9k_2ghz_chantable) +
+		     ARRAY_SIZE(ath9k_5ghz_chantable) !=
+		     ATH9K_NUM_CHANNELS);
+
 	if (test_bit(ATH9K_MODE_11G, sc->sc_ah->caps.wireless_modes)) {
 		channels = kmemdup(ath9k_2ghz_chantable,
 			sizeof(ath9k_2ghz_chantable), GFP_KERNEL);