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From: Felix Fietkau <nbd@openwrt.org>
Date: Wed, 14 Jan 2015 14:13:15 +0100
Subject: [PATCH] ath9k: fix race condition in irq processing during hardware
reset
To fix invalid hardware accesses, the commit
"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>
---
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -285,6 +285,7 @@ static int ath_reset_internal(struct ath
__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
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;
/*
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