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From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Cornelia Huck <cohuck@redhat.com>
Cc: KVM <kvm@vger.kernel.org>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	linux-s390 <linux-s390@vger.kernel.org>
Subject: [PATCH 4/5] KVM: s390: drop use of spin lock in __floating_irq_kick
Date: Wed, 20 Dec 2017 16:52:59 +0100	[thread overview]
Message-ID: <20171220155300.102321-5-borntraeger@de.ibm.com> (raw)
In-Reply-To: <20171220155300.102321-1-borntraeger@de.ibm.com>

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>
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

  parent reply	other threads:[~2017-12-20 15:52 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-20 15:52 [PATCH 0/5] preview of first chunk of s390 patches for kvm/next Christian Borntraeger
2017-12-20 15:52 ` [PATCH 1/5] s390x/mm: cleanup gmap_pte_op_walk() Christian Borntraeger
2017-12-20 16:33   ` Cornelia Huck
2017-12-20 15:52 ` [PATCH 2/5] KVM: s390: use created_vcpus in more places Christian Borntraeger
2017-12-20 16:35   ` Cornelia Huck
2018-01-08 11:08   ` David Hildenbrand
2017-12-20 15:52 ` [PATCH 3/5] KVM: s390: add debug tracing for cpu features of CPU model Christian Borntraeger
2017-12-20 16:37   ` Cornelia Huck
2018-01-08 11:14   ` David Hildenbrand
2017-12-20 15:52 ` Christian Borntraeger [this message]
2017-12-20 16:40   ` [PATCH 4/5] KVM: s390: drop use of spin lock in __floating_irq_kick Cornelia Huck
2018-01-08 12:10   ` David Hildenbrand
2017-12-20 15:53 ` [PATCH 5/5] kvm_config: add CONFIG_S390_GUEST Christian Borntraeger
2017-12-20 16:44   ` Cornelia Huck

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