Commit ae2ff239 authored Oct 17, 2014 by Sujith Manoharan Committed by John W. Linville Oct 27, 2014

ath9k: Set ATH_OP_HW_RESET before HW reset



When a HW reset is done, the interrupt tasklet is
disabled before ISRs are disabled in the HW. This
allows a small window where the HW can still generate
interrupts. Since the tasklet is disabled and not killed,
it is not scheduled but deferred for execution at a later
time.

This happens because ATH_OP_HW_RESET is not set when ath_reset()
is called. When the hw_reset_work workqueue is used, this
problem doesn't arise because ATH_OP_HW_RESET is set
and the ISR bails out.

Set ATH_OP_HW_RESET properly in ath_reset() to avoid
this race - all the ath_reset_internal() callers have
been converted to use ath_reset() in the previous patch.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

parent 5555c955

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

+12 −0

Original line number	Diff line number	Diff line
		@@ -598,10 +598,17 @@ irqreturn_t ath_isr(int irq, void *dev)
		#undef SCHED_INTR
		}

		/*
		* This function is called when a HW reset cannot be deferred
		* and has to be immediate.
		*/
		int ath_reset(struct ath_softc sc, struct ath9k_channel hchan)
		{
		struct ath_common *common = ath9k_hw_common(sc->sc_ah);
		int r;

		set_bit(ATH_OP_HW_RESET, &common->op_flags);

		ath9k_ps_wakeup(sc);
		r = ath_reset_internal(sc, hchan);
		ath9k_ps_restore(sc);
		@@ -609,6 +616,11 @@ int ath_reset(struct ath_softc sc, struct ath9k_channel hchan)
		return r;
		}

		/*
		* When a HW reset can be deferred, it is added to the
		* hw_reset_work workqueue, but we set ATH_OP_HW_RESET before
		* queueing.
		*/
		void ath9k_queue_reset(struct ath_softc *sc, enum ath_reset_type type)
		{
		struct ath_common *common = ath9k_hw_common(sc->sc_ah);