From ff311bc11a7e2da95e1e17f99b7e4951c7060547 Mon Sep 17 00:00:00 2001
From: Simon Wunderlich <simon.wunderlich@s2003.tu-chemnitz.de>
Date: Tue, 3 Sep 2013 19:43:18 +0200
Subject: [PATCH] nl80211: allow CAC only if no operation is going on

A CAC should fail if it is triggered while the interface is already
running.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 net/wireless/nl80211.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index ae617112b8f5..2838206ddad3 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -5591,6 +5591,9 @@ static int nl80211_start_radar_detection(struct sk_buff *skb,
 	if (err)
 		return err;
 
+	if (netif_carrier_ok(dev))
+		return -EBUSY;
+
 	if (wdev->cac_started)
 		return -EBUSY;
 
-- 
2.39.5