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Subject[patch 04/13] Make sure enabled wait psw is loaded in default_idle.
From: Heiko Carstens <heiko.carstens@de.ibm.com>

If both NO_IDLE_HZ and VIRT_TIMER are disabled default_idle won't load
an enabled wait psw and busy loop instead. This is because the
idle_chain is empty and the return value of atomic_notifier_call_chain
will be NOTIFY_DONE, which causes default_idle to return instead of
loading an enabled wait psw.
Fix this by calling __atomic_notifier_call_chain instead and add proper
return value handling.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
arch/s390/kernel/process.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
Index: quilt-2.6/arch/s390/kernel/process.c
===================================================================
--- quilt-2.6.orig/arch/s390/kernel/process.c
+++ quilt-2.6/arch/s390/kernel/process.c
@@ -114,24 +114,27 @@ extern void s390_handle_mcck(void);
static void default_idle(void)
{
int cpu, rc;
+ int nr_calls = 0;
+ void *hcpu;
#ifdef CONFIG_SMP
struct s390_idle_data *idle;
#endif

/* CPU is going idle. */
cpu = smp_processor_id();
-
+ hcpu = (void *)(long)cpu;
local_irq_disable();
if (need_resched()) {
local_irq_enable();
return;
}

- rc = atomic_notifier_call_chain(&idle_chain,
- S390_CPU_IDLE, (void *)(long) cpu);
- if (rc != NOTIFY_OK && rc != NOTIFY_DONE)
- BUG();
- if (rc != NOTIFY_OK) {
+ rc = __atomic_notifier_call_chain(&idle_chain, S390_CPU_IDLE, hcpu, -1,
+ &nr_calls);
+ if (rc == NOTIFY_BAD) {
+ nr_calls--;
+ __atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE,
+ hcpu, nr_calls, NULL);
local_irq_enable();
return;
}
--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.



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