ath9k: fix race condition in enabling/disabling IRQs

am: 1aeced70f7

Change-Id: Ifcf5e90179052b66d3e1d97ade82f98a92c0b14d

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

@@ -959,6 +959,7 @@ struct ath_softc {
 	struct survey_info *cur_survey;
 	struct survey_info survey[ATH9K_NUM_CHANNELS];
 
+	spinlock_t intr_lock;
 	struct tasklet_struct intr_tq;
 	struct tasklet_struct bcon_tasklet;
 	struct ath_hw *sc_ah;

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

@@ -619,6 +619,7 @@ static int ath9k_init_softc(u16 devid, struct ath_softc *sc,
 		common->bt_ant_diversity = 1;
 
 	spin_lock_init(&common->cc_lock);
+	spin_lock_init(&sc->intr_lock);
 	spin_lock_init(&sc->sc_serial_rw);
 	spin_lock_init(&sc->sc_pm_lock);
 	spin_lock_init(&sc->chan_lock);

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

@@ -805,21 +805,12 @@ void ath9k_hw_disable_interrupts(struct ath_hw *ah)
 }
 EXPORT_SYMBOL(ath9k_hw_disable_interrupts);
 
-void ath9k_hw_enable_interrupts(struct ath_hw *ah)
+static void __ath9k_hw_enable_interrupts(struct ath_hw *ah)
 {
 	struct ath_common *common = ath9k_hw_common(ah);
 	u32 sync_default = AR_INTR_SYNC_DEFAULT;
 	u32 async_mask;
 
-	if (!(ah->imask & ATH9K_INT_GLOBAL))
-		return;
-
-	if (!atomic_inc_and_test(&ah->intr_ref_cnt)) {
-		ath_dbg(common, INTERRUPT, "Do not enable IER ref count %d\n",
-			atomic_read(&ah->intr_ref_cnt));
-		return;
-	}
-
 	if (AR_SREV_9340(ah) || AR_SREV_9550(ah) || AR_SREV_9531(ah) ||
 	    AR_SREV_9561(ah))
 		sync_default &= ~AR_INTR_SYNC_HOST1_FATAL;
@@ -841,6 +832,39 @@ void ath9k_hw_enable_interrupts(struct ath_hw *ah)
 	ath_dbg(common, INTERRUPT, "AR_IMR 0x%x IER 0x%x\n",
 		REG_READ(ah, AR_IMR), REG_READ(ah, AR_IER));
 }
+
+void ath9k_hw_resume_interrupts(struct ath_hw *ah)
+{
+	struct ath_common *common = ath9k_hw_common(ah);
+
+	if (!(ah->imask & ATH9K_INT_GLOBAL))
+		return;
+
+	if (atomic_read(&ah->intr_ref_cnt) != 0) {
+		ath_dbg(common, INTERRUPT, "Do not enable IER ref count %d\n",
+			atomic_read(&ah->intr_ref_cnt));
+		return;
+	}
+
+	__ath9k_hw_enable_interrupts(ah);
+}
+EXPORT_SYMBOL(ath9k_hw_resume_interrupts);
+
+void ath9k_hw_enable_interrupts(struct ath_hw *ah)
+{
+	struct ath_common *common = ath9k_hw_common(ah);
+
+	if (!(ah->imask & ATH9K_INT_GLOBAL))
+		return;
+
+	if (!atomic_inc_and_test(&ah->intr_ref_cnt)) {
+		ath_dbg(common, INTERRUPT, "Do not enable IER ref count %d\n",
+			atomic_read(&ah->intr_ref_cnt));
+		return;
+	}
+
+	__ath9k_hw_enable_interrupts(ah);
+}
 EXPORT_SYMBOL(ath9k_hw_enable_interrupts);
 
 void ath9k_hw_set_interrupts(struct ath_hw *ah)

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

@@ -748,6 +748,7 @@ void ath9k_hw_set_interrupts(struct ath_hw *ah);
 void ath9k_hw_enable_interrupts(struct ath_hw *ah);
 void ath9k_hw_disable_interrupts(struct ath_hw *ah);
 void ath9k_hw_kill_interrupts(struct ath_hw *ah);
+void ath9k_hw_resume_interrupts(struct ath_hw *ah);
 
 void ar9002_hw_attach_mac_ops(struct ath_hw *ah);
 

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

@@ -373,21 +373,20 @@ void ath9k_tasklet(unsigned long data)
 	struct ath_common *common = ath9k_hw_common(ah);
 	enum ath_reset_type type;
 	unsigned long flags;
-	u32 status = sc->intrstatus;
+	u32 status;
 	u32 rxmask;
 
+	spin_lock_irqsave(&sc->intr_lock, flags);
+	status = sc->intrstatus;
+	sc->intrstatus = 0;
+	spin_unlock_irqrestore(&sc->intr_lock, flags);
+
 	ath9k_ps_wakeup(sc);
 	spin_lock(&sc->sc_pcu_lock);
 
 	if (status & ATH9K_INT_FATAL) {
 		type = RESET_TYPE_FATAL_INT;
 		ath9k_queue_reset(sc, type);
-
-		/*
-		 * Increment the ref. counter here so that
-		 * interrupts are enabled in the reset routine.
-		 */
-		atomic_inc(&ah->intr_ref_cnt);
 		ath_dbg(common, RESET, "FATAL: Skipping interrupts\n");
 		goto out;
 	}
@@ -403,11 +402,6 @@ void ath9k_tasklet(unsigned long data)
 			type = RESET_TYPE_BB_WATCHDOG;
 			ath9k_queue_reset(sc, type);
 
-			/*
-			 * Increment the ref. counter here so that
-			 * interrupts are enabled in the reset routine.
-			 */
-			atomic_inc(&ah->intr_ref_cnt);
 			ath_dbg(common, RESET,
 				"BB_WATCHDOG: Skipping interrupts\n");
 			goto out;
@@ -420,7 +414,6 @@ void ath9k_tasklet(unsigned long data)
 		if ((sc->gtt_cnt >= MAX_GTT_CNT) && !ath9k_hw_check_alive(ah)) {
 			type = RESET_TYPE_TX_GTT;
 			ath9k_queue_reset(sc, type);
-			atomic_inc(&ah->intr_ref_cnt);
 			ath_dbg(common, RESET,
 				"GTT: Skipping interrupts\n");
 			goto out;
@@ -477,7 +470,7 @@ void ath9k_tasklet(unsigned long data)
 	ath9k_btcoex_handle_interrupt(sc, status);
 
 	/* re-enable hardware interrupt */
-	ath9k_hw_enable_interrupts(ah);
+	ath9k_hw_resume_interrupts(ah);
 out:
 	spin_unlock(&sc->sc_pcu_lock);
 	ath9k_ps_restore(sc);
@@ -541,7 +534,9 @@ irqreturn_t ath_isr(int irq, void *dev)
 		return IRQ_NONE;
 
 	/* Cache the status */
-	sc->intrstatus = status;
+	spin_lock(&sc->intr_lock);
+	sc->intrstatus |= status;
+	spin_unlock(&sc->intr_lock);
 
 	if (status & SCHED_INTR)
 		sched = true;
@@ -587,7 +582,7 @@ chip_reset:
 
 	if (sched) {
 		/* turn off every interrupt */
-		ath9k_hw_disable_interrupts(ah);
+		ath9k_hw_kill_interrupts(ah);
 		tasklet_schedule(&sc->intr_tq);
 	}