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ath9k: fix race condition in irq processing during hardware reset 

To fix invalid hardware accesses, the commit 872b5d814f ("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: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
This commit is contained in:
Felix Fietkau 2015-01-14 14:17:36 +01:00 committed by Kalle Valo
parent 7b05520160
commit e3f31175a3
1 changed files with 3 additions and 4 deletions
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7
drivers/net/wireless/ath/ath9k/main.c
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@ -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;
/*