KVM: async_pf: use list_first_entry

To make the intention clearer, use list_first_entry instead of
list_entry.
Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/async_pf.c

@@ -109,7 +109,7 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 	/* cancel outstanding work queue item */
 	while (!list_empty(&vcpu->async_pf.queue)) {
 		struct kvm_async_pf *work =
-			list_entry(vcpu->async_pf.queue.next,
+			list_first_entry(&vcpu->async_pf.queue,
 					 typeof(*work), queue);
 		list_del(&work->queue);
 
@@ -127,7 +127,7 @@ void kvm_clear_async_pf_completion_queue(struct kvm_vcpu *vcpu)
 	spin_lock(&vcpu->async_pf.lock);
 	while (!list_empty(&vcpu->async_pf.done)) {
 		struct kvm_async_pf *work =
-			list_entry(vcpu->async_pf.done.next,
+			list_first_entry(&vcpu->async_pf.done,
 					 typeof(*work), link);
 		list_del(&work->link);
 		kmem_cache_free(async_pf_cache, work);