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Commit e3f31175 authored by Felix Fietkau's avatar Felix Fietkau Committed by Kalle Valo
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ath9k: fix race condition in irq processing during hardware reset 



To fix invalid hardware accesses, the commit 872b5d81 ("ath9k: do not
access hardware on IRQs during reset") made the irq handler ignore interrupts
emitted after queueing a hardware reset (which disables the IRQ). This left a
small time window for the IRQ to get re-enabled by the tasklet, which caused
IRQ storms.  Instead of returning IRQ_NONE when ATH_OP_HW_RESET is set, disable
the IRQ entirely for the duration of the reset.

Signed-off-by: default avatarFelix Fietkau <nbd@openwrt.org>
Signed-off-by: default avatarKalle Valo <kvalo@codeaurora.org>
parent 7b055201

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

+3 −4
Original line number Diff line number Diff line
@@ -285,6 +285,7 @@ static int ath_reset_internal(struct ath_softc *sc, struct ath9k_channel *hchan) 


	__ath_cancel_work(sc);



	disable_irq(sc->irq);

	tasklet_disable(&sc->intr_tq);

	tasklet_disable(&sc->bcon_tasklet);

	spin_lock_bh(&sc->sc_pcu_lock);
@@ -331,6 +332,7 @@ static int ath_reset_internal(struct ath_softc *sc, struct ath9k_channel *hchan) 
		r = -EIO;



out:

	enable_irq(sc->irq);

	spin_unlock_bh(&sc->sc_pcu_lock);

	tasklet_enable(&sc->bcon_tasklet);

	tasklet_enable(&sc->intr_tq);
@@ -512,9 +514,6 @@ irqreturn_t ath_isr(int irq, void *dev) 
	if (!ah || test_bit(ATH_OP_INVALID, &common->op_flags))

		return IRQ_NONE;



	if (!AR_SREV_9100(ah) && test_bit(ATH_OP_HW_RESET, &common->op_flags))

		return IRQ_NONE;



	/* shared irq, not for us */

	if (!ath9k_hw_intrpend(ah))

		return IRQ_NONE;
@@ -529,7 +528,7 @@ irqreturn_t ath_isr(int irq, void *dev) 
	ath9k_debug_sync_cause(sc, sync_cause);

	status &= ah->imask;	/* discard unasked-for bits */



	if (AR_SREV_9100(ah) && test_bit(ATH_OP_HW_RESET, &common->op_flags))

	if (test_bit(ATH_OP_HW_RESET, &common->op_flags))

		return IRQ_HANDLED;



	/*