KVM: x86: Handle the kthread worker using the new API

Use the new API to create and destroy the "kvm-pit" kthread
worker. The API hides some implementation details.

In particular, kthread_create_worker() allocates and initializes
struct kthread_worker. It runs the kthread the right way
and stores task_struct into the worker structure.

kthread_destroy_worker() flushes all pending works, stops
the kthread and frees the structure.

This patch does not change the existing behavior except for
dynamically allocating struct kthread_worker and storing
only the pointer of this structure.

It is compile tested only because I did not find an easy
way how to run the code. Well, it should be pretty safe
given the nature of the change.

Signed-off-by: Petr Mladek <pmladek@suse.com>
Message-Id: <1476877847-11217-1-git-send-email-pmladek@suse.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 6 insertions, 9 deletions

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 16a7134eedac..a78b445ce411 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -212,7 +212,7 @@ static void kvm_pit_ack_irq(struct kvm_irq_ack_notifier *kian)
          */
         smp_mb();
         if (atomic_dec_if_positive(&ps->pending) > 0)
-                kthread_queue_work(&pit->worker, &pit->expired);
+                kthread_queue_work(pit->worker, &pit->expired);
 }
 
 void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
@@ -272,7 +272,7 @@ static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
         if (atomic_read(&ps->reinject))
                 atomic_inc(&ps->pending);
 
-        kthread_queue_work(&pt->worker, &pt->expired);
+        kthread_queue_work(pt->worker, &pt->expired);
 
         if (ps->is_periodic) {
                 hrtimer_add_expires_ns(&ps->timer, ps->period);
@@ -667,10 +667,8 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
         pid_nr = pid_vnr(pid);
         put_pid(pid);
 
-        kthread_init_worker(&pit->worker);
-        pit->worker_task = kthread_run(kthread_worker_fn, &pit->worker,
-                                       "kvm-pit/%d", pid_nr);
-        if (IS_ERR(pit->worker_task))
+        pit->worker = kthread_create_worker(0, "kvm-pit/%d", pid_nr);
+        if (IS_ERR(pit->worker))
                 goto fail_kthread;
 
         kthread_init_work(&pit->expired, pit_do_work);
@@ -713,7 +711,7 @@ fail_register_speaker:
 fail_register_pit:
         mutex_unlock(&kvm->slots_lock);
         kvm_pit_set_reinject(pit, false);
-        kthread_stop(pit->worker_task);
+        kthread_destroy_worker(pit->worker);
 fail_kthread:
         kvm_free_irq_source_id(kvm, pit->irq_source_id);
 fail_request:
@@ -730,8 +728,7 @@ void kvm_free_pit(struct kvm *kvm)
                 kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->speaker_dev);
                 kvm_pit_set_reinject(pit, false);
                 hrtimer_cancel(&pit->pit_state.timer);
-                kthread_flush_work(&pit->expired);
-                kthread_stop(pit->worker_task);
+                kthread_destroy_worker(pit->worker);
                 kvm_free_irq_source_id(kvm, pit->irq_source_id);
                 kfree(pit);
         }