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mac80211: handle sched_scan_stopped vs. hw restart race

Message ID 1452004086-11480-1-git-send-email-emmanuel.grumbach@intel.com
State Accepted
Delegated to: Johannes Berg
Headers show

Commit Message

Emmanuel Grumbach Jan. 5, 2016, 2:28 p.m. UTC
From: Eliad Peller <eliad@wizery.com>

On hw restart, mac80211 might try to reconfigure already
stopped sched scan, if ieee80211_sched_scan_stopped_work()
wasn't scheduled yet.

This in turn will keep the device driver with scheduled scan
configured, while both mac80211 and cfg80211 will clear
their sched scan state once the work is scheduled.

Fix it by ignoring ieee80211_sched_scan_stopped() calls
while in hw restart, and flush the work before starting
the reconfiguration.

Signed-off-by: Eliad Peller <eliadx.peller@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
---
 net/mac80211/main.c | 1 +
 net/mac80211/scan.c | 8 ++++++++
 2 files changed, 9 insertions(+)
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Patch

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index ed4c8e6..8190bf2 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -248,6 +248,7 @@  static void ieee80211_restart_work(struct work_struct *work)
 
 	/* wait for scan work complete */
 	flush_workqueue(local->workqueue);
+	flush_work(&local->sched_scan_stopped_work);
 
 	WARN(test_bit(SCAN_HW_SCANNING, &local->scanning),
 	     "%s called with hardware scan in progress\n", __func__);
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index a413e52..8eb68ef 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -1213,6 +1213,14 @@  void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw)
 
 	trace_api_sched_scan_stopped(local);
 
+	/*
+	 * this shouldn't really happen, so for simplicity
+	 * simply ignore it, and let mac80211 reconfigure
+	 * the sched scan later on.
+	 */
+	if (local->in_reconfig)
+		return;
+
 	schedule_work(&local->sched_scan_stopped_work);
 }
 EXPORT_SYMBOL(ieee80211_sched_scan_stopped);