xen: Resume PMU from non-atomic context

Resuming PMU currently triggers a warning from ___might_sleep() (assuming
CONFIG_DEBUG_ATOMIC_SLEEP is set) when xen_pmu_init() allocates GFP_KERNEL
page because we are in state resembling atomic context.

Move resuming PMU to xen_arch_resume() which is called in regular context.
For symmetry move suspending PMU to xen_arch_suspend() as well.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: <stable@vger.kernel.org> # 4.3
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
(cherry picked from commit de0afc9bdeeadaa998797d2333c754bf9f4d5dcf)
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>

diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
index 3c0d968c8c67fb6eb3076c78c27d019b994290c9..7ed65d0db4d4983409d48b7907f58fd5c88137ee 100644 (file)
--- a/arch/x86/xen/suspend.c
+++ b/arch/x86/xen/suspend.c
@@ -63,26 +63,16 @@ static void xen_pv_post_suspend(int suspend_cancelled)
 
 void xen_arch_pre_suspend(void)
 {
-       int cpu;
-
-       for_each_online_cpu(cpu)
-               xen_pmu_finish(cpu);
-
        if (xen_pv_domain())
                xen_pv_pre_suspend();
 }
 
 void xen_arch_post_suspend(int cancelled)
 {
-       int cpu;
-
        if (xen_pv_domain())
                xen_pv_post_suspend(cancelled);
        else
                xen_hvm_post_suspend(cancelled);
-
-       for_each_online_cpu(cpu)
-               xen_pmu_init(cpu);
 }
 
 static void xen_vcpu_notify_restore(void *data)
@@ -101,10 +91,20 @@ static void xen_vcpu_notify_suspend(void *data)
 
 void xen_arch_resume(void)
 {
+       int cpu;
+
        on_each_cpu(xen_vcpu_notify_restore, NULL, 1);
+
+       for_each_online_cpu(cpu)
+               xen_pmu_init(cpu);
 }
 
 void xen_arch_suspend(void)
 {
+       int cpu;
+
+       for_each_online_cpu(cpu)
+               xen_pmu_finish(cpu);
+
        on_each_cpu(xen_vcpu_notify_suspend, NULL, 1);
 }