From 0212f2602a38e740d5a96aba4cebfc2ebc993ecf Mon Sep 17 00:00:00 2001 From: Vaidyanathan Srinivasan Date: Mon, 1 Mar 2010 02:58:16 +0000 Subject: [PATCH] powerpc: Move checks in pseries_mach_cpu_die() 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 Cc: Gautham R Shenoy Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/platforms/pseries/hotplug-cpu.c | 32 ++++++++++---------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index 349e0af9389a..fefb7f84800b 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())); + + /* + * 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(); + } } - if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) { - unregister_slb_shadow(hwcpu, __pa(get_slb_shadow())); + /* Requested state is CPU_STATE_OFFLINE at this point */ + WARN_ON(get_preferred_offline_state(cpu) != CPU_STATE_OFFLINE); - /* - * 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) { - - 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();