KVM: Initialize irqfd from kvm_init().

Currently, eventfd introduces module_init/module_exit functions
to initialize/cleanup the irqfd workqueue. This only works, however,
if no other module_init/module_exit functions are built into the
same module.

Let's just move the initialization and cleanup to kvm_init and kvm_exit.
This way, it is also clearer where kvm startup may fail.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0e919a1..faf05bd 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2898,6 +2898,9 @@
 	int r;
 	int cpu;
 
+	r = kvm_irqfd_init();
+	if (r)
+		goto out_irqfd;
 	r = kvm_arch_init(opaque);
 	if (r)
 		goto out_fail;
@@ -2978,6 +2981,8 @@
 out_free_0:
 	kvm_arch_exit();
 out_fail:
+	kvm_irqfd_exit();
+out_irqfd:
 	return r;
 }
 EXPORT_SYMBOL_GPL(kvm_init);
@@ -2994,6 +2999,7 @@
 	on_each_cpu(hardware_disable_nolock, NULL, 1);
 	kvm_arch_hardware_unsetup();
 	kvm_arch_exit();
+	kvm_irqfd_exit();
 	free_cpumask_var(cpus_hardware_enabled);
 }
 EXPORT_SYMBOL_GPL(kvm_exit);