diff mbox series

[10/14] ath9k: Use tasklet_disable_in_atomic()

Message ID 20210309084242.313899703@linutronix.de (mailing list archive)
State Not Applicable
Delegated to: Kalle Valo
Headers show
Series tasklets: Replace the spin wait loops and make it RT safe | expand

Commit Message

Thomas Gleixner March 9, 2021, 8:42 a.m. UTC 
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

All callers of ath9k_beacon_ensure_primary_slot() are preemptible /
acquire a mutex except for this callchain:

  spin_lock_bh(&sc->sc_pcu_lock);
  ath_complete_reset()
  -> ath9k_calculate_summary_state()
     -> ath9k_beacon_ensure_primary_slot()

It's unclear how that can be distangled, so use tasklet_disable_in_atomic()
for now. This allows tasklet_disable() to become sleepable once the
remaining atomic users are cleaned up.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: ath9k-devel@qca.qualcomm.com
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
---
 drivers/net/wireless/ath/ath9k/beacon.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Kalle Valo March 9, 2021, 10:23 a.m. UTC | #1 
Thomas Gleixner <tglx@linutronix.de> writes:

> From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
>
> All callers of ath9k_beacon_ensure_primary_slot() are preemptible /
> acquire a mutex except for this callchain:
>
>   spin_lock_bh(&sc->sc_pcu_lock);
>   ath_complete_reset()
>   -> ath9k_calculate_summary_state()
>      -> ath9k_beacon_ensure_primary_slot()
>
> It's unclear how that can be distangled, so use tasklet_disable_in_atomic()
> for now. This allows tasklet_disable() to become sleepable once the
> remaining atomic users are cleaned up.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: ath9k-devel@qca.qualcomm.com
> Cc: Kalle Valo <kvalo@codeaurora.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: linux-wireless@vger.kernel.org
> Cc: netdev@vger.kernel.org
> ---
>  drivers/net/wireless/ath/ath9k/beacon.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

I assume this goes via some other tree:

Acked-by: Kalle Valo <kvalo@codeaurora.org>
diff mbox series

Patch

--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -251,7 +251,7 @@  void ath9k_beacon_ensure_primary_slot(st
 	int first_slot = ATH_BCBUF;
 	int slot;
 
-	tasklet_disable(&sc->bcon_tasklet);
+	tasklet_disable_in_atomic(&sc->bcon_tasklet);
 
 	/* Find first taken slot. */
 	for (slot = 0; slot < ATH_BCBUF; slot++) {