mac80211: fix scan locking wrt. hw scan

Releasing the scan mutex while starting scans
can lead to unexpected things happening, so
we shouldn't do that. Fix that and hold the
mutex across the scan triggering.

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

1 files changed, 0 insertions, 14 deletions

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 41f20fb7e670..872d7b6ef6b3 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -400,19 +400,7 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
         else
                 __set_bit(SCAN_SW_SCANNING, &local->scanning);
 
-        /*
-         * Kicking off the scan need not be protected,
-         * only the scan variable stuff, since now
-         * local->scan_req is assigned and other callers
-         * will abort their scan attempts.
-         *
-         * This avoids too many locking dependencies
-         * so that the scan completed calls have more
-         * locking freedom.
-         */
-
         ieee80211_recalc_idle(local);
-        mutex_unlock(&local->scan_mtx);
 
         if (local->ops->hw_scan) {
                 WARN_ON(!ieee80211_prep_hw_scan(local));
@@ -420,8 +408,6 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
         } else
                 rc = ieee80211_start_sw_scan(local);
 
-        mutex_lock(&local->scan_mtx);
-
         if (rc) {
                 kfree(local->hw_scan_req);
                 local->hw_scan_req = NULL;