[PATCH] mac80211: Prevent starting of hw scan if it is already in progress

[Teemu Paasikivi <ext-teemu.3.paasikivi@xxxxxxxxx>]

Added checking of status of scanning to ieee80211_scan_work when hw
scanning is used. It is possible to scan_work get executed while scan
has already been started. Previously this has led to a state where, when
the driver returned EBUSY, the stack aborted scan while hw was left
scanning. That has caused warnings from ieee80211_scan_completed when
the scan actually has been completed.

Signed-off-by: Teemu Paasikivi <ext-teemu.3.paasikivi@xxxxxxxxx>
---
 net/mac80211/ieee80211_i.h |    1 +
 net/mac80211/scan.c        |    8 +++++++-
 2 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 741fb8b..1d14f7c 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -756,6 +756,7 @@ struct ieee80211_local {
 	/* Scanning and BSS list */
 	struct mutex scan_mtx;
 	unsigned long scanning;
+	bool hw_scan_continue;
 	struct cfg80211_ssid scan_ssid;
 	struct cfg80211_scan_request *int_scan_req;
 	struct cfg80211_scan_request *scan_req, *hw_scan_req;
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 75a8597..4e4bad0 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -265,12 +265,14 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 
 	was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
 	if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
+		local->hw_scan_continue =  true;
 		ieee80211_queue_delayed_work(&local->hw,
 					     &local->scan_work, 0);
 		mutex_unlock(&local->scan_mtx);
 		return;
 	}
 
+	local->hw_scan_continue = false;
 	kfree(local->hw_scan_req);
 	local->hw_scan_req = NULL;
 
@@ -652,7 +654,11 @@ void ieee80211_scan_work(struct work_struct *work)
 	}
 
 	if (local->hw_scan_req) {
-		int rc = drv_hw_scan(local, local->hw_scan_req);
+		int rc = 0;
+
+		if (!local->scanning || local->hw_scan_continue)
+			rc = drv_hw_scan(local, local->hw_scan_req);
+
 		mutex_unlock(&local->scan_mtx);
 		if (rc)
 			ieee80211_scan_completed(&local->hw, true);
-- 
1.5.6.3

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