[PATCH tip/core/rcu 7/9] arm64: Use common outgoing-CPU-notification code

From: Paul E. McKenney
Date: Tue May 12 2015 - 17:50:41 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: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
arch/arm64/kernel/smp.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 2cb008177252..a899c1beff54 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -253,15 +253,13 @@ static int op_cpu_kill(unsigned int cpu)
return cpu_ops[cpu]->cpu_kill(cpu);

-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_crit("CPU%u: cpu didn't die\n", cpu);
@@ -294,7 +292,7 @@ void cpu_die(void)

/* Tell __cpu_die() that this CPU is now safe to dispose of */
- complete(&cpu_died);
+ (void)cpu_report_death();

* Actually shutdown the CPU. This must never fail. The specific hotplug

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