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mac80211: fix scan cancel on ifdown 

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@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg 2009-08-25 16:33:47 +02:00 committed by John W. Linville
parent 6bd5f5208f
commit 15db0b7fd8
2 changed files with 8 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
net/mac80211/iface.c
View File

@ -497,30 +497,8 @@ static int ieee80211_stop(struct net_device *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

9
net/mac80211/scan.c
View File

@ -280,6 +280,7 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
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_struct *work)
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(struct ieee80211_sub_if_data *sdata,
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 ieee80211_local *local)
* 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);
}