KVM: Replace smp_mb() with smp_mb_after_atomic() in the kvm_make_all_cpus_request()

Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index db021c3..402590d 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -170,8 +170,8 @@
 		kvm_make_request(req, vcpu);
 		cpu = vcpu->cpu;
 
-		/* Set ->requests bit before we read ->mode */
-		smp_mb();
+		/* Set ->requests bit before we read ->mode. */
+		smp_mb__after_atomic();
 
 		if (cpus != NULL && cpu != -1 && cpu != me &&
 		      kvm_vcpu_exiting_guest_mode(vcpu) != OUTSIDE_GUEST_MODE)