CHROMIUM: mac80211: handle potential race between suspend and scan completion
If suspend starts while ieee80211_scan_completed() is running, between
the point where SCAN_COMPLETED is set and the work is queued,
ieee80211_scan_cancel() will not catch the work and we may finish
suspending before the work is actually executed, leaving the scan
running while suspended.
To fix this race, queue the scan work during resume if the
SCAN_COMPLETED flag is set and flush it immediately.
Change-Id: I1149d2202746a748d8f178d909d738a4411525bd
Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
diff --git a/drivers/net/wireless/iwl7000/mac80211/ieee80211_i.h b/drivers/net/wireless/iwl7000/mac80211/ieee80211_i.h
index b5e248e..21dfb5e 100644
--- a/drivers/net/wireless/iwl7000/mac80211/ieee80211_i.h
+++ b/drivers/net/wireless/iwl7000/mac80211/ieee80211_i.h
@@ -1698,7 +1698,8 @@
{
struct ieee80211_local *local = hw_to_local(hw);
- WARN(test_bit(SCAN_HW_SCANNING, &local->scanning),
+ WARN(test_bit(SCAN_HW_SCANNING, &local->scanning) &&
+ !test_bit(SCAN_COMPLETED, &local->scanning),
"%s: resume with hardware scan still in progress\n",
wiphy_name(hw->wiphy));
diff --git a/drivers/net/wireless/iwl7000/mac80211/util.c b/drivers/net/wireless/iwl7000/mac80211/util.c
index af2e77e..c1c14e6 100644
--- a/drivers/net/wireless/iwl7000/mac80211/util.c
+++ b/drivers/net/wireless/iwl7000/mac80211/util.c
@@ -1938,6 +1938,18 @@
mb();
local->resuming = false;
+ /* It's possible that we don't handle the scan completion in
+ * time during suspend, so if it's still marked as completed
+ * here, queue the work and flush it to clean things up.
+ * Instead of calling the worker function directly here, we
+ * really queue it to avoid potential races with other flows
+ * scheduling the same work.
+ */
+ if (test_bit(SCAN_COMPLETED, &local->scanning)) {
+ ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0);
+ flush_delayed_work(&local->scan_work);
+ }
+
list_for_each_entry(sdata, &local->interfaces, list) {
if (!ieee80211_sdata_running(sdata))
continue;
