diff options
| author | Felix Fietkau <nbd@nbd.name> | 2017-02-02 10:14:52 +0100 |
|---|---|---|
| committer | Kalle Valo <kvalo@qca.qualcomm.com> | 2017-02-07 11:00:25 +0200 |
| commit | 3a5e969bb2f6692a256352649355d56d018d6b88 (patch) | |
| tree | 51dc21b1b0ddc1ee2236c819fcd7194dbf70a94f /drivers/net/wireless/ath/ath9k/main.c | |
| parent | a34d0a0da1abae46a5f6ebd06fb0ec484ca099d9 (diff) | |
ath9k: fix race condition in enabling/disabling IRQs
The code currently relies on refcounting to disable IRQs from within the
IRQ handler and re-enabling them again after the tasklet has run.
However, due to race conditions sometimes the IRQ handler might be
called twice, or the tasklet may not run at all (if interrupted in the
middle of a reset).
This can cause nasty imbalances in the irq-disable refcount which will
get the driver permanently stuck until the entire radio has been stopped
and started again (ath_reset will not recover from this).
Instead of using this fragile logic, change the code to ensure that
running the irq handler during tasklet processing is safe, and leave the
refcount untouched.
Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Diffstat (limited to 'drivers/net/wireless/ath/ath9k/main.c')
| -rw-r--r-- | drivers/net/wireless/ath/ath9k/main.c | 27 |
1 files changed, 11 insertions, 16 deletions
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c index 0345d6ec564f..9e65d14e7b1e 100644 --- a/drivers/net/wireless/ath/ath9k/main.c +++ b/drivers/net/wireless/ath/ath9k/main.c @@ -374,21 +374,20 @@ void ath9k_tasklet(unsigned long data) struct ath_common *common = ath9k_hw_common(ah); enum ath_reset_type type; unsigned long flags; - u32 status = sc->intrstatus; + u32 status; u32 rxmask; + spin_lock_irqsave(&sc->intr_lock, flags); + status = sc->intrstatus; + sc->intrstatus = 0; + spin_unlock_irqrestore(&sc->intr_lock, flags); + ath9k_ps_wakeup(sc); spin_lock(&sc->sc_pcu_lock); if (status & ATH9K_INT_FATAL) { type = RESET_TYPE_FATAL_INT; ath9k_queue_reset(sc, type); - - /* - * Increment the ref. counter here so that - * interrupts are enabled in the reset routine. - */ - atomic_inc(&ah->intr_ref_cnt); ath_dbg(common, RESET, "FATAL: Skipping interrupts\n"); goto out; } @@ -404,11 +403,6 @@ void ath9k_tasklet(unsigned long data) type = RESET_TYPE_BB_WATCHDOG; ath9k_queue_reset(sc, type); - /* - * Increment the ref. counter here so that - * interrupts are enabled in the reset routine. - */ - atomic_inc(&ah->intr_ref_cnt); ath_dbg(common, RESET, "BB_WATCHDOG: Skipping interrupts\n"); goto out; @@ -421,7 +415,6 @@ void ath9k_tasklet(unsigned long data) if ((sc->gtt_cnt >= MAX_GTT_CNT) && !ath9k_hw_check_alive(ah)) { type = RESET_TYPE_TX_GTT; ath9k_queue_reset(sc, type); - atomic_inc(&ah->intr_ref_cnt); ath_dbg(common, RESET, "GTT: Skipping interrupts\n"); goto out; @@ -478,7 +471,7 @@ void ath9k_tasklet(unsigned long data) ath9k_btcoex_handle_interrupt(sc, status); /* re-enable hardware interrupt */ - ath9k_hw_enable_interrupts(ah); + ath9k_hw_resume_interrupts(ah); out: spin_unlock(&sc->sc_pcu_lock); ath9k_ps_restore(sc); @@ -542,7 +535,9 @@ irqreturn_t ath_isr(int irq, void *dev) return IRQ_NONE; /* Cache the status */ - sc->intrstatus = status; + spin_lock(&sc->intr_lock); + sc->intrstatus |= status; + spin_unlock(&sc->intr_lock); if (status & SCHED_INTR) sched = true; @@ -588,7 +583,7 @@ chip_reset: if (sched) { /* turn off every interrupt */ - ath9k_hw_disable_interrupts(ah); + ath9k_hw_kill_interrupts(ah); tasklet_schedule(&sc->intr_tq); } |