We can not call cancel_delayed_work_sync(&priv->scan_check) with
priv->mutex locked because workqueue function iwl_bg_scan_check()
take that lock internally.
We do not need to synchronize when canceling priv->scan_check work.
We can avoid races (sending double abort command or send no
command at all) using STATUS_SCAN_ABORT bit. Moreover
current iwl_bg_scan_check() code seems to be broken, as
we should not send abort commands when currently aborting.
I did not test patch yet, just want to know if it is theoretically
correct. Except obvious circular priv->mutex locking fix, maybe it
can help with warning in ieee80211_scan_completed, which is still
reported by the users from time to time.
diff --git a/drivers/net/wireless/iwlwifi/iwl-scan.c b/drivers/net/wireless/iwlwifi/iwl-scan.c
index 2a7c399..b0c6b04 100644
--- a/drivers/net/wireless/iwlwifi/iwl-scan.c
+++ b/drivers/net/wireless/iwlwifi/iwl-scan.c
@@ -429,11 +429,10 @@ void iwl_bg_scan_check(struct work_struct *data)
return;
mutex_lock(&priv->mutex);
- if (test_bit(STATUS_SCANNING, &priv->status) ||
- test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
- IWL_DEBUG_SCAN(priv, "Scan completion watchdog resetting "
- "adapter (%dms)\n",
- jiffies_to_msecs(IWL_SCAN_CHECK_WATCHDOG));
+ if (test_bit(STATUS_SCANNING, &priv->status) &&
+ !test_bit(STATUS_SCAN_ABORTING, &priv->status)) {
+ IWL_DEBUG_SCAN(priv, "Scan completion watchdog (%dms)\n",
+ jiffies_to_msecs(IWL_SCAN_CHECK_WATCHDOG));
if (!test_bit(STATUS_EXIT_PENDING, &priv->status))
iwl_send_scan_abort(priv);
@@ -498,12 +497,11 @@ void iwl_bg_abort_scan(struct work_struct *work)
!test_bit(STATUS_GEO_CONFIGURED, &priv->status))
return;
- mutex_lock(&priv->mutex);
-
- cancel_delayed_work_sync(&priv->scan_check);
- set_bit(STATUS_SCAN_ABORTING, &priv->status);
- iwl_send_scan_abort(priv);
+ cancel_delayed_work(&priv->scan_check);
+ mutex_lock(&priv->mutex);
+ if (test_bit(STATUS_SCAN_ABORTING, &priv->status))
+ iwl_send_scan_abort(priv);
mutex_unlock(&priv->mutex);
}
EXPORT_SYMBOL(iwl_bg_abort_scan);
--
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