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Commit d28232b4 authored by Stanislaw Gruszka's avatar Stanislaw Gruszka Committed by John W. Linville
Browse files

iwlwifi: fix scan abort 



Fix possible double priv->mutex lock introduced by commit
a69b03e9
"iwlwifi: cancel scan watchdog in iwl_bg_abort_scan" .
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.

Signed-off-by: default avatarStanislaw Gruszka <sgruszka@redhat.com>
CC: stable@kernel.org
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 16345910

drivers/net/wireless/iwlwifi/iwl-scan.c

+8 −10
Original line number Diff line number Diff line
@@ -429,10 +429,9 @@ 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",

	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))
@@ -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(&priv->scan_check);



	cancel_delayed_work_sync(&priv->scan_check);

	set_bit(STATUS_SCAN_ABORTING, &priv->status);

	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);