KVM: Use syscore_ops instead of sysdev class and sysdev

KVM uses a sysdev class and a sysdev for executing kvm_suspend()
after interrupts have been turned off on the boot CPU (during system
suspend) and for executing kvm_resume() before turning on interrupts
on the boot CPU (during system resume).  However, since both of these
functions ignore their arguments, the entire mechanism may be
replaced with a struct syscore_ops object which is simpler.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Avi Kivity <avi@redhat.com>

1 files changed, 8 insertions, 26 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 1fa0d292119a..24444527f422 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -30,7 +30,7 @@
 #include <linux/debugfs.h>
 #include <linux/highmem.h>
 #include <linux/file.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/cpu.h>
 #include <linux/sched.h>
 #include <linux/cpumask.h>
@@ -2447,33 +2447,26 @@ static void kvm_exit_debug(void)
         debugfs_remove(kvm_debugfs_dir);
 }
 
-static int kvm_suspend(struct sys_device *dev, pm_message_t state)
+static int kvm_suspend(void)
 {
         if (kvm_usage_count)
                 hardware_disable_nolock(NULL);
         return 0;
 }
 
-static int kvm_resume(struct sys_device *dev)
+static void kvm_resume(void)
 {
         if (kvm_usage_count) {
                 WARN_ON(raw_spin_is_locked(&kvm_lock));
                 hardware_enable_nolock(NULL);
         }
-        return 0;
 }
 
-static struct sysdev_class kvm_sysdev_class = {
-        .name = "kvm",
+static struct syscore_ops kvm_syscore_ops = {
         .suspend = kvm_suspend,
         .resume = kvm_resume,
 };
 
-static struct sys_device kvm_sysdev = {
-        .id = 0,
-        .cls = &kvm_sysdev_class,
-};
-
 struct page *bad_page;
 pfn_t bad_pfn;
 
@@ -2557,14 +2550,6 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
                 goto out_free_2;
         register_reboot_notifier(&kvm_reboot_notifier);
 
-        r = sysdev_class_register(&kvm_sysdev_class);
-        if (r)
-                goto out_free_3;
-
-        r = sysdev_register(&kvm_sysdev);
-        if (r)
-                goto out_free_4;
-
         /* A kmem cache lets us meet the alignment requirements of fx_save. */
         if (!vcpu_align)
                 vcpu_align = __alignof__(struct kvm_vcpu);
@@ -2572,7 +2557,7 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
                                            0, NULL);
         if (!kvm_vcpu_cache) {
                 r = -ENOMEM;
-                goto out_free_5;
+                goto out_free_3;
         }
 
         r = kvm_async_pf_init();
@@ -2589,6 +2574,8 @@ int kvm_init(void *opaque, unsigned vcpu_size, unsigned vcpu_align,
                 goto out_unreg;
         }
 
+        register_syscore_ops(&kvm_syscore_ops);
+
         kvm_preempt_ops.sched_in = kvm_sched_in;
         kvm_preempt_ops.sched_out = kvm_sched_out;
 
@@ -2600,10 +2587,6 @@ out_unreg:
         kvm_async_pf_deinit();
 out_free:
         kmem_cache_destroy(kvm_vcpu_cache);
-out_free_5:
-        sysdev_unregister(&kvm_sysdev);
-out_free_4:
-        sysdev_class_unregister(&kvm_sysdev_class);
 out_free_3:
         unregister_reboot_notifier(&kvm_reboot_notifier);
         unregister_cpu_notifier(&kvm_cpu_notifier);
@@ -2631,8 +2614,7 @@ void kvm_exit(void)
         misc_deregister(&kvm_dev);
         kmem_cache_destroy(kvm_vcpu_cache);
         kvm_async_pf_deinit();
-        sysdev_unregister(&kvm_sysdev);
-        sysdev_class_unregister(&kvm_sysdev_class);
+        unregister_syscore_ops(&kvm_syscore_ops);
         unregister_reboot_notifier(&kvm_reboot_notifier);
         unregister_cpu_notifier(&kvm_cpu_notifier);
         on_each_cpu(hardware_disable_nolock, NULL, 1);