Revert "xen/smp: Fix CPU online/offline bug triggering a BUG: scheduling while atomic."

This reverts commit 41bd956de3dfdc3a43708fe2e0c8096c69064a1e.

The fix is incorrect and not appropiate for the latest kernels.
In fact it _causes_ the BUG: scheduling while atomic while
doing vCPU hotplug.

Suggested-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 4f7d259..34bc4ce 100644 (file)
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -432,13 +432,6 @@ static void __cpuinit xen_play_dead(void) /* used only with HOTPLUG_CPU */
        play_dead_common();
        HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
        cpu_bringup();
-       /*
-        * Balance out the preempt calls - as we are running in cpu_idle
-        * loop which has been called at bootup from cpu_bringup_and_idle.
-        * The cpucpu_bringup_and_idle called cpu_bringup which made a
-        * preempt_disable() So this preempt_enable will balance it out.
-        */
-       preempt_enable();
 }
 
 #else /* !CONFIG_HOTPLUG_CPU */