diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c
index 4bd9e2b..833b46c 100644
--- a/drivers/net/wireless/cisco/airo.c
+++ b/drivers/net/wireless/cisco/airo.c
@@ -5794,7 +5794,7 @@
 		fwrq->m = ieee80211_frequency_to_channel(f);
 	}
 	/* Setting by channel number */
-	if((fwrq->m > 1000) || (fwrq->e > 0))
+	if (fwrq->m < 0 || fwrq->m > 1000 || fwrq->e > 0)
 		rc = -EOPNOTSUPP;
 	else {
 		int channel = fwrq->m;