[PATCH tip/core/rcu 8/9] arm: Use common outgoing-CPU-notification code

From: Paul E. McKenney
Date: Tue May 12 2015 - 17:53:08 EST

From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>

This commit removes the open-coded CPU-offline notification with new
common code. In particular, this change avoids calling scheduler code
using RCU from an offline CPU that RCU is ignoring. This is a minimal
change. A more intrusive change might invoke the cpu_check_up_prepare()
and cpu_set_state_online() functions at CPU-online time, which would
allow onlining throw an error if the CPU did not go offline properly.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
arch/arm/kernel/smp.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index cca5b8758185..8ef0ef0287ee 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -218,15 +218,13 @@ int __cpu_disable(void)
return 0;

-static DECLARE_COMPLETION(cpu_died);
* called on the thread which is asking for a CPU to be shutdown -
* waits until shutdown has completed, or it is timed out.
void __cpu_die(unsigned int cpu)
- if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
+ if (!cpu_wait_death(cpu, 5)) {
pr_err("CPU%u: cpu didn't die\n", cpu);
@@ -272,7 +270,7 @@ void __ref cpu_die(void)
* this returns, power and/or clocks can be removed at any point
* from this CPU and its cache by platform_cpu_kill().
- complete(&cpu_died);
+ (void)cpu_report_death();

* Ensure that the cache lines associated with that completion are

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