rtlwifi: rtl8821ae: Fix potential race condition

Flag rfchange_inprogress in struct rtl_ps_ctl is protected by a spinlock
in most routines but not in rtl8821ae_dm_watchdog() which could
lead to a race condition. The necessary locking to prevent this condition
is added.

Reported-by: Pavel Andrianov <andrianov@ispras.ru>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Pavel Andrianov <andrianov@ispras.ru>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/realtek/rtlwifi/rtl8821ae/dm.c

@@ -2949,6 +2949,7 @@ void rtl8821ae_dm_watchdog(struct ieee80211_hw *hw)
 	if (ppsc->p2p_ps_info.p2p_ps_mode)
 		fw_ps_awake = false;
 
+	spin_lock(&rtlpriv->locks.rf_ps_lock);
 	if ((ppsc->rfpwr_state == ERFON) &&
 	    ((!fw_current_inpsmode) && fw_ps_awake) &&
 	    (!ppsc->rfchange_inprogress)) {
@@ -2967,6 +2968,7 @@ void rtl8821ae_dm_watchdog(struct ieee80211_hw *hw)
 			rtl8821ae_dm_check_txpower_tracking_thermalmeter(hw);
 		rtl8821ae_dm_iq_calibrate(hw);
 	}
+	spin_unlock(&rtlpriv->locks.rf_ps_lock);
 
 	rtlpriv->dm.dbginfo.num_qry_beacon_pkt = 0;
 	RT_TRACE(rtlpriv, COMP_DIG, DBG_DMESG, "\n");