[PATCH 2/2] clocksource/arm_arch_timer: Use static_branch_enable_nolock()

From: Marc Zyngier
Date: Thu Jul 27 2017 - 05:37:54 EST


Use the new static_branch_enable_nolock function to switch
the workaround static key on the CPU hotplug path.

Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>
---
drivers/clocksource/arm_arch_timer.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index aae87c4c546e..4f41acf59072 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -455,7 +455,11 @@ void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa
per_cpu(timer_unstable_counter_workaround, i) = wa;
}

- static_branch_enable(&arch_timer_read_ool_enabled);
+ /*
+ * Use the _nolock version, as we're called from the CPU
+ * hotplug framework. Otherwise, we end-up in deadlock-land.
+ */
+ static_branch_enable_nolock(&arch_timer_read_ool_enabled);

/*
* Don't use the vdso fastpath if errata require using the
--
2.11.0