Re: [kvm:queue 41/42] arch/s390/kvm/interrupt.c:428:12: warning: ignoring return value of 'vcpu_load

[Avi Kivity <avi@redhat.com>]

On 09/27/2012 05:02 PM, Christian Borntraeger wrote:
> On 20/09/12 07:22, Michael S. Tsirkin wrote:
>> On Thu, Sep 20, 2012 at 08:16:08AM +0800, Fengguang Wu wrote:
>>> Hi Michael,
>>>
>>> FYI, there are new compile warnings show up in
>>>
>>> tree:   git://git.kernel.org/pub/scm/virt/kvm/kvm.git queue
>>> head:   879238fecc051d95037ae76332916209a7770709
>>> commit: 9fc77441e5e1bf80b794cc546d2243ee9f4afb75 [41/42] KVM: make processes waiting on vcpu mutex killable
>>> config: s390-defconfig
>>>
>>> All error/warnings:
>>>
>>> arch/s390/kvm/interrupt.c: In function 'kvm_s390_handle_wait':
>>> arch/s390/kvm/interrupt.c:428:12: warning: ignoring return value of 'vcpu_load', declared with attribute warn_unused_result [-Wunused-result]
>>>
>>> vim +428 arch/s390/kvm/interrupt.c
>>>    418		add_wait_queue(&vcpu->arch.local_int.wq, &wait);
>>>    419		while (list_empty(&vcpu->arch.local_int.list) &&
>>>    420			list_empty(&vcpu->arch.local_int.float_int->list) &&
>>>    421			(!vcpu->arch.local_int.timer_due) &&
>>>    422			!signal_pending(current)) {
>>>    423			set_current_state(TASK_INTERRUPTIBLE);
>>>    424			spin_unlock_bh(&vcpu->arch.local_int.lock);
>>>    425			spin_unlock(&vcpu->arch.local_int.float_int->lock);
>>>    426			vcpu_put(vcpu);
>>>    427			schedule();
>>>  > 428			vcpu_load(vcpu);
>>>    429			spin_lock(&vcpu->arch.local_int.float_int->lock);
>>>    430			spin_lock_bh(&vcpu->arch.local_int.lock);
> 
> IIRC schedule will do vcpu put/load anyway via the preempt notifiers. So the right fix
> is probably to just remove the vcpu_put/load around that schedule.
> Will double check and send a patch.

Yes, this is correct.  On a preemptible kernel this happens all the time.


-- 
error compiling committee.c: too many arguments to function