When an interface is taken down while a scan is
pending -- i.e. a scan request was accepted but
not yet acted upon due to other work being in
progress -- we currently do not properly cancel
that scan and end up getting stuck. Fix this by
doing better checks when an interface is taken
down.
Signed-off-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
---
net/mac80211/iface.c | 26 ++------------------------
net/mac80211/scan.c | 9 ++++++---
2 files changed, 8 insertions(+), 27 deletions(-)
--- wireless-testing.orig/net/mac80211/iface.c 2009-08-25 14:39:06.000000000 +0200
+++ wireless-testing/net/mac80211/iface.c 2009-08-25 14:39:42.000000000 +0200
@@ -497,30 +497,8 @@ static int ieee80211_stop(struct net_dev
}
/* fall through */
default:
- if (local->scan_sdata == sdata) {
- if (!local->ops->hw_scan)
- cancel_delayed_work_sync(&local->scan_work);
- /*
- * The software scan can no longer run now, so we can
- * clear out the scan_sdata reference. However, the
- * hardware scan may still be running. The complete
- * function must be prepared to handle a NULL value.
- */
- local->scan_sdata = NULL;
- /*
- * The memory barrier guarantees that another CPU
- * that is hardware-scanning will now see the fact
- * that this interface is gone.
- */
- smp_mb();
- /*
- * If software scanning, complete the scan but since
- * the scan_sdata is NULL already don't send out a
- * scan event to userspace -- the scan is incomplete.
- */
- if (test_bit(SCAN_SW_SCANNING, &local->scanning))
- ieee80211_scan_completed(&local->hw, true);
- }
+ if (local->scan_sdata == sdata)
+ ieee80211_scan_cancel(local);
/*
* Disable beaconing for AP and mesh, IBSS can't
--- wireless-testing.orig/net/mac80211/scan.c 2009-08-25 14:37:44.000000000 +0200
+++ wireless-testing/net/mac80211/scan.c 2009-08-25 15:50:07.000000000 +0200
@@ -280,6 +280,7 @@ void ieee80211_scan_completed(struct iee
if (local->scan_req != local->int_scan_req)
cfg80211_scan_done(local->scan_req, aborted);
local->scan_req = NULL;
+ local->scan_sdata = NULL;
was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
local->scanning = 0;
@@ -660,6 +661,7 @@ void ieee80211_scan_work(struct work_str
int rc;
local->scan_req = NULL;
+ local->scan_sdata = NULL;
rc = __ieee80211_start_scan(sdata, req);
mutex_unlock(&local->scan_mtx);
@@ -742,7 +744,7 @@ int ieee80211_request_internal_scan(stru
void ieee80211_scan_cancel(struct ieee80211_local *local)
{
- bool swscan;
+ bool abortscan;
cancel_delayed_work_sync(&local->scan_work);
@@ -751,9 +753,10 @@ void ieee80211_scan_cancel(struct ieee80
* queued -- mostly at suspend under RTNL.
*/
mutex_lock(&local->scan_mtx);
- swscan = test_bit(SCAN_SW_SCANNING, &local->scanning);
+ abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
+ (!local->scanning && local->scan_req);
mutex_unlock(&local->scan_mtx);
- if (swscan)
+ if (abortscan)
ieee80211_scan_completed(&local->hw, true);
}
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