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authorEmmanuel Grumbach <emmanuel.grumbach@intel.com>2013-09-16 11:12:07 +0300
committerJohannes Berg <johannes.berg@intel.com>2013-10-09 18:40:07 +0200
commita754055a1296fcbe6f32de3a5eaca6efb2fd1865 (patch)
tree6812b556c369c031478a94d6de4b2b6259bd2ca9
parent22c4ceed0184318ec5a6182c6d75d398452c2e39 (diff)
downloadlinux-stericsson-a754055a1296fcbe6f32de3a5eaca6efb2fd1865.tar.gz
mac80211: correctly close cancelled scans
__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. Cc: stable@vger.kernel.org Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
-rw-r--r--net/mac80211/ieee80211_i.h3
-rw-r--r--net/mac80211/scan.c19
2 files changed, 22 insertions, 0 deletions
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index b6186517ec56..611abfcfb5eb 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -893,6 +893,8 @@ struct tpt_led_trigger {
* 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,
@@ -900,6 +902,7 @@ enum {
SCAN_ONCHANNEL_SCANNING,
SCAN_COMPLETED,
SCAN_ABORTED,
+ SCAN_HW_CANCELLED,
};
/**
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 08afe74b98f4..d2d17a449224 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -238,6 +238,9 @@ static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
enum ieee80211_band band;
int i, ielen, n_chans;
+ if (test_bit(SCAN_HW_CANCELLED, &local->scanning))
+ return false;
+
do {
if (local->hw_scan_band == IEEE80211_NUM_BANDS)
return false;
@@ -940,7 +943,23 @@ void ieee80211_scan_cancel(struct ieee80211_local *local)
if (!local->scan_req)
goto out;
+ /*
+ * We have a scan running and the driver already reported completion,
+ * but the worker hasn't run yet or is stuck on the mutex - mark it as
+ * cancelled.
+ */
+ if (test_bit(SCAN_HW_SCANNING, &local->scanning) &&
+ test_bit(SCAN_COMPLETED, &local->scanning)) {
+ set_bit(SCAN_HW_CANCELLED, &local->scanning);
+ goto out;
+ }
+
if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {
+ /*
+ * Make sure that __ieee80211_scan_completed doesn't trigger a
+ * scan on another band.
+ */
+ set_bit(SCAN_HW_CANCELLED, &local->scanning);
if (local->ops->cancel_hw_scan)
drv_cancel_hw_scan(local,
rcu_dereference_protected(local->scan_sdata,