mac80211: allow scan to complete from any context

The ieee80211_scan_completed() function was a frequent
source of potential deadlocks, since it is called by
drivers but may call back into drivers, so drivers had
to make sure to call it without any locks held, which
frequently lead to more complex code in drivers. Avoid
that problem by allowing the function to be called in
any context, and queueing the actual work it does.
Also update the documentation for it to indicate this.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 9e225f01497b..31713320258c 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -596,11 +596,17 @@ enum queue_stop_reason {
  *      determine if we are on the operating channel or not
  * @SCAN_OFF_CHANNEL: We're off our operating channel for scanning,
  *      gets only set in conjunction with SCAN_SW_SCANNING
+ * @SCAN_COMPLETED: Set for our scan work function when the driver reported
+ *      that the scan completed.
+ * @SCAN_ABORTED: Set for our scan work function when the driver reported
+ *      a scan complete for an aborted scan.
  */
 enum {
         SCAN_SW_SCANNING,
         SCAN_HW_SCANNING,
         SCAN_OFF_CHANNEL,
+        SCAN_COMPLETED,
+        SCAN_ABORTED,
 };
 
 /**