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Diffstat (limited to 'net/mac80211/main.c')
-rw-r--r--net/mac80211/main.c33
1 files changed, 25 insertions, 8 deletions
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index ebdec7106d6..4bfac4b41c5 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -564,14 +564,6 @@ static int ieee80211_stop(struct net_device *dev)
synchronize_rcu();
skb_queue_purge(&sdata->u.sta.skb_queue);
- if (local->scan_sdata == sdata) {
- if (!local->ops->hw_scan) {
- local->sta_sw_scanning = 0;
- cancel_delayed_work(&local->scan_work);
- } else
- local->sta_hw_scanning = 0;
- }
-
sdata->u.sta.flags &= ~IEEE80211_STA_PRIVACY_INVOKED;
kfree(sdata->u.sta.extra_ie);
sdata->u.sta.extra_ie = NULL;
@@ -585,6 +577,31 @@ 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 (local->sta_sw_scanning)
+ ieee80211_scan_completed(&local->hw);
+ }
+
conf.vif = &sdata->vif;
conf.type = sdata->vif.type;
conf.mac_addr = dev->dev_addr;