From: Michael Mueller <mimu@linux.vnet.ibm.com>
Date: Mon, 20 Nov 2017 10:37:30 +0100
Subject: KVM: s390: drop use of spin lock in __floating_irq_kick
Git-commit: 588629385c4b96c436cef55dff75eef7f90cd5f0
Patch-mainline: v4.16-rc1
References: jsc#SLE-6412

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>
Signed-off-by: Bruce Rogers <brogers@suse.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 5b8089b0d3ee..98c67ca343a8 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -1582,7 +1582,6 @@ 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);
@@ -1594,7 +1593,6 @@ 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);
 }