Rearrange condition checks for better code readability and
prevention of possible race conditions when
preferred_offline_state can potentially change during the
execution of pseries_mach_cpu_die(). The patch will make
pseries_mach_cpu_die() put cpu in one of the consistent states
and not hit the run over BUG()
Signed-off-by: Vaidyanathan Srinivasan <sva...@linux.vnet.ibm.com>
Cc: Gautham R Shenoy <e...@in.ibm.com>
---
arch/powerpc/platforms/pseries/hotplug-cpu.c | 30 +++++++++++++-------------
1 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c
b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 9be7af4..39ecb40 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -140,25 +140,25 @@ static void pseries_mach_cpu_die(void)
if (!get_lppaca()->shared_proc)
get_lppaca()->donate_dedicated_cpu = 0;
get_lppaca()->idle = 0;
- }
- if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) {
- unregister_slb_shadow(hwcpu, __pa(get_slb_shadow()));
+ if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) {
+ unregister_slb_shadow(hwcpu, __pa(get_slb_shadow()));
- /*
- * Call to start_secondary_resume() will not return.
- * Kernel stack will be reset and start_secondary()
- * will be called to continue the online operation.
- */
- start_secondary_resume();
+ /*
+ * Call to start_secondary_resume() will not return.
+ * Kernel stack will be reset and start_secondary()
+ * will be called to continue the online operation.
+ */
+ start_secondary_resume();
+ }
+ }
- } else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) {
+ /* Requested state is CPU_STATE_OFFLINE at this point */
+ WARN_ON(get_preferred_offline_state(cpu) != CPU_STATE_OFFLINE);
- set_cpu_current_state(cpu, CPU_STATE_OFFLINE);
- unregister_slb_shadow(hard_smp_processor_id(),
- __pa(get_slb_shadow()));
- rtas_stop_self();
- }
+ set_cpu_current_state(cpu, CPU_STATE_OFFLINE);
+ unregister_slb_shadow(hwcpu, __pa(get_slb_shadow()));
+ rtas_stop_self();
/* Should never get here... */
BUG();
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