ath9k: Handle fatal interrupts properly

When a fatal interrupt is received or it is detected that the baseband
has hung, the chip has to be reset immediately.  Otherwise, we end up
processing spurious interrupts. Ensure that we bail out properly in
the ISR when the reset work hasn't completed yet.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/ath9k.h

@@ -611,6 +611,7 @@ enum sc_op_flags {
 	SC_OP_TSF_RESET,
 	SC_OP_ANI_RUN,
 	SC_OP_PRIM_STA_VIF,
+	SC_OP_HW_RESET,
 };
 
 /* Powersave flags */

drivers/net/wireless/ath/ath9k/main.c

@@ -218,6 +218,8 @@ static bool ath_complete_reset(struct ath_softc *sc, bool start)
 
 	ath9k_cmn_update_txpow(ah, sc->curtxpow,
 			       sc->config.txpowlimit, &sc->curtxpow);
+
+	clear_bit(SC_OP_HW_RESET, &sc->sc_flags);
 	ath9k_hw_set_interrupts(ah);
 	ath9k_hw_enable_interrupts(ah);
 
@@ -362,6 +364,7 @@ void ath9k_tasklet(unsigned long data)
 
 		RESET_STAT_INC(sc, type);
 #endif
+		set_bit(SC_OP_HW_RESET, &sc->sc_flags);
 		ieee80211_queue_work(sc->hw, &sc->hw_reset_work);
 		goto out;
 	}
@@ -438,12 +441,14 @@ irqreturn_t ath_isr(int irq, void *dev)
 	if (test_bit(SC_OP_INVALID, &sc->sc_flags))
 		return IRQ_NONE;
 
-
 	/* shared irq, not for us */
 
 	if (!ath9k_hw_intrpend(ah))
 		return IRQ_NONE;
 
+	if(test_bit(SC_OP_HW_RESET, &sc->sc_flags))
+		return IRQ_HANDLED;
+
 	/*
 	 * Figure out the reason(s) for the interrupt.  Note
 	 * that the hal returns a pseudo-ISR that may include