[PATCH] kvm-390: fix wait_queue handling

Christian Bornträger
2009-07-16T15:17:39Z

From: Christian Borntraeger <borntraeger@de.ibm.com>

There are two waitqueues in kvm for wait handling:
vcpu->wq for virt/kvm/kvm_main.c and
vpcu->arch.local_int.wq for the s390 specific wait code.

the wait handling in kvm_s390_handle_wait was broken by using different
wait_queues for add_wait queue and remove_wait_queue.

There are two options to fix the problem:
o move all the s390 specific code to vcpu->wq and remove
vcpu->arch.local_int.wq
o move all the s390 specific code to vcpu->arch.local_int.wq

This patch chooses the 2nd variant for two reasons:
o s390 does not use kvm_vcpu_block but implements its own enabled wait
handling.
Having a separate wait_queue make it clear, that our wait mechanism is
different
o the patch is much smaller

Report-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
arch/s390/kvm/interrupt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Index: kvm/arch/s390/kvm/interrupt.c
===================================================================
--- kvm.orig/arch/s390/kvm/interrupt.c
+++ kvm/arch/s390/kvm/interrupt.c
@@ -386,7 +386,7 @@ no_timer:
}
__unset_cpu_idle(vcpu);
__set_current_state(TASK_RUNNING);
- remove_wait_queue(&vcpu->wq, &wait);
+ remove_wait_queue(&vcpu->arch.local_int.wq, &wait);
spin_unlock_bh(&vcpu->arch.local_int.lock);
spin_unlock(&vcpu->arch.local_int.float_int->lock);
hrtimer_try_to_cancel(&vcpu->arch.ckc_timer);