mac80211: correctly close cancelled scans

commit a754055a1296fcbe6f32de3a5eaca6efb2fd1865 upstream.

__ieee80211_scan_completed is called from a worker. This
means that the following flow is possible.

 * driver calls ieee80211_scan_completed
 * mac80211 cancels the scan (that is already complete)
 * __ieee80211_scan_completed runs

When scan_work will finally run, it will see that the scan
hasn't been aborted and might even trigger another scan on
another band. This leads to a situation where cfg80211's
scan is not done and no further scan can be issued.

Fix this by setting a new flag when a HW scan is being
cancelled so that no other scan will be triggered.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 9ca8e32..92ef04c 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -842,6 +842,8 @@
  *	that the scan completed.
  * @SCAN_ABORTED: Set for our scan work function when the driver reported
  *	a scan complete for an aborted scan.
+ * @SCAN_HW_CANCELLED: Set for our scan work function when the scan is being
+ *	cancelled.
  */
 enum {
 	SCAN_SW_SCANNING,
@@ -849,6 +851,7 @@
 	SCAN_ONCHANNEL_SCANNING,
 	SCAN_COMPLETED,
 	SCAN_ABORTED,
+	SCAN_HW_CANCELLED,
 };
 
 /**