[ Upstream commit bca1a10046 ]
This reverts commit c7dacf5b0f,
"mailbox: avoid timer start from callback"
The previous commit was reverted since it lead to a race that
caused the hrtimer to not be started at all. The check for
hrtimer_active() in msg_submit() will return true if the
callback function txdone_hrtimer() is currently running. This
function could return HRTIMER_NORESTART and then the timer
will not be restarted, and also msg_submit() will not start
the timer. This will lead to a message actually being submitted
but no timer will start to check for its compleation.
The original fix that added checking hrtimer_active() was added to
avoid a warning with hrtimer_forward. Looking in the kernel
another solution to avoid this warning is to check hrtimer_is_queued()
before calling hrtimer_forward_now() instead. This however requires a
lock so the timer is not started by msg_submit() inbetween this check
and the hrtimer_forward() call.
Fixes: c7dacf5b0f ("mailbox: avoid timer start from callback")
Signed-off-by: Björn Ardö <bjorn.ardo@axis.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Björn Ardö
16b5013fa1