ath9k: fix interrupt storms on queued hardware reset

commit b74713d04effbacd3d126ce94cec18742187b6ce
"ath9k: Handle fatal interrupts properly" introduced a race condition, where
IRQs are being left enabled, however the irq handler returns IRQ_HANDLED
while the reset is still queued without addressing the IRQ cause.
This leads to an IRQ storm that prevents the system from even getting to
the reset code.

Fix this by disabling IRQs in the handler without touching intr_ref_cnt.

Cc: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Cc: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath/ath9k/mac.c b/drivers/net/wireless/ath/ath9k/mac.c
index 7990cd55599cd319a51537ed0ad1981b6edf9a4b..b42be910a83dc94845fa6be33370357b18416e2f 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/mac.c
+++ b/drivers/net/wireless/ath/ath9k/mac.c
@@ -773,15 +773,10 @@ bool ath9k_hw_intrpend(struct ath_hw *ah)
 }
 EXPORT_SYMBOL(ath9k_hw_intrpend);
 
-void ath9k_hw_disable_interrupts(struct ath_hw *ah)
+void ath9k_hw_kill_interrupts(struct ath_hw *ah)
 {
        struct ath_common *common = ath9k_hw_common(ah);
 
-       if (!(ah->imask & ATH9K_INT_GLOBAL))
-               atomic_set(&ah->intr_ref_cnt, -1);
-       else
-               atomic_dec(&ah->intr_ref_cnt);
-
        ath_dbg(common, INTERRUPT, "disable IER\n");
        REG_WRITE(ah, AR_IER, AR_IER_DISABLE);
        (void) REG_READ(ah, AR_IER);
@@ -793,6 +788,17 @@ void ath9k_hw_disable_interrupts(struct ath_hw *ah)
                (void) REG_READ(ah, AR_INTR_SYNC_ENABLE);
        }
 }
+EXPORT_SYMBOL(ath9k_hw_kill_interrupts);
+
+void ath9k_hw_disable_interrupts(struct ath_hw *ah)
+{
+       if (!(ah->imask & ATH9K_INT_GLOBAL))
+               atomic_set(&ah->intr_ref_cnt, -1);
+       else
+               atomic_dec(&ah->intr_ref_cnt);
+
+       ath9k_hw_kill_interrupts(ah);
+}
 EXPORT_SYMBOL(ath9k_hw_disable_interrupts);
 
 void ath9k_hw_enable_interrupts(struct ath_hw *ah)

diff --git a/drivers/net/wireless/ath/ath9k/mac.h b/drivers/net/wireless/ath/ath9k/mac.h
index 0eba36dca6f8fe897dcbbdc56cd0318af46f4fba..4a745e68dd941d9351e4fe911b47d76ec288551d 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/mac.h
+++ b/drivers/net/wireless/ath/ath9k/mac.h
@@ -738,6 +738,7 @@ bool ath9k_hw_intrpend(struct ath_hw *ah);
 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 ar9002_hw_attach_mac_ops(struct ath_hw *ah);
 

diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 6049d8b82855a7542192b247657e58964fc9f496..a22df749b8db3d8641b4ef8cb78ad99b9e34adbb 100644 (file)
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -462,8 +462,10 @@ irqreturn_t ath_isr(int irq, void *dev)
        if (!ath9k_hw_intrpend(ah))
                return IRQ_NONE;
 
-       if(test_bit(SC_OP_HW_RESET, &sc->sc_flags))
+       if (test_bit(SC_OP_HW_RESET, &sc->sc_flags)) {
+               ath9k_hw_kill_interrupts(ah);
                return IRQ_HANDLED;
+       }
 
        /*
         * Figure out the reason(s) for the interrupt.  Note