[GIT PULL 4/6] KVM: s390: drop use of spin lock in __floating_irq_kick

Christian Borntraeger
2018-01-16T15:03:12Z

From: Michael Mueller <mimu@linux.vnet.ibm.com>

It is not required to take to a lock to protect access to the cpuflags
of the local interrupt structure of a vcpu as the performed operation
is an atomic_or.

Signed-off-by: Michael Mueller <mimu@linux.vnet.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
arch/s390/kvm/interrupt.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 024ad8bcc516..818aa4248b0f 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -1569,7 +1569,6 @@ static void __floating_irq_kick(struct kvm *kvm, u64 type)

/* make the VCPU drop out of the SIE, or wake it up if sleeping */
li = &dst_vcpu->arch.local_int;
- spin_lock(&li->lock);
switch (type) {
case KVM_S390_MCHK:
atomic_or(CPUSTAT_STOP_INT, li->cpuflags);
@@ -1581,7 +1580,6 @@ static void __floating_irq_kick(struct kvm *kvm, u64 type)
atomic_or(CPUSTAT_EXT_INT, li->cpuflags);
break;
}
- spin_unlock(&li->lock);
kvm_s390_vcpu_wakeup(dst_vcpu);
}

--
2.13.4