tree 4cff363c691f8e4ef4b41f503f25657ef48f959a
parent 93c1f1db1a7421545e9aae9fb6091668ca570f2b
author Felix Fietkau <nbd@nbd.name> 1486026892 +0100
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1489297306 +0100

ath9k: fix race condition in enabling/disabling IRQs

commit 3a5e969bb2f6692a256352649355d56d018d6b88 upstream.

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.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>