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Wed, 28 May 2025 09:55:09 +0000 (GMT) From: Claudio Imbrenda To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, frankja@linux.ibm.com, borntraeger@de.ibm.com, seiden@linux.ibm.com, nsg@linux.ibm.com, nrb@linux.ibm.com, david@redhat.com, hca@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com, gor@linux.ibm.com, schlameuss@linux.ibm.com Subject: [PATCH v5 2/4] KVM: s390: Remove unneeded srcu lock Date: Wed, 28 May 2025 11:55:00 +0200 Message-ID: <20250528095502.226213-3-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250528095502.226213-1-imbrenda@linux.ibm.com> References: <20250528095502.226213-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=OIIn3TaB c=1 sm=1 tr=0 ts=6836dd83 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=dt9VzEwgFbYA:10 a=VnNF1IyMAAAA:8 a=-g0RikXFz7zMAnJmuvsA:9 X-Proofpoint-GUID: h13K_zD8G2gSbVxjBv37Gt9RwCBjf0rg X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNTI4MDA4MiBTYWx0ZWRfX3d1Pf17qIWHF KdeRODGzXpsL5shoqJFKIy5amA0o0sU2bezKkBiFa9QWgqRWFPJRL0kpC4CRhfeNfac1q6JQWTh PnWsbwKbE1lcNUTQHfT+bkmavF3HwOwI+VPhpsV6TXHpgfcEUm2P4wRKGnKiAKByuLy5wvfttv0 clgt86tdwYM2YvzYF0kqnKSbm5+Y1PbfUFL5XTr6Cm00WLPVrpcWs4GVle0O/KBFxH4Jvj5EcLl /Uyb3C/StRZZRXnYMlMLjB82We0swx3HMDf1lsuuDerQeGiW7fGGn+JArnlg6zK3Nti6nzzr+NI PNbNIvTUe6FddQ72o0D5YPQu9H0iXDsvjFZGCPIQ17QjncTQCDzZgaCytM+eKl8hGuIAfhp4nUa FpVyYz4yr4ZFCF5Pi5Ur2HXDmEMWfp2sdQCMuEOabMCkbYsrOzP9Jj5+CfetxOFzLgbvyz5X X-Proofpoint-ORIG-GUID: h13K_zD8G2gSbVxjBv37Gt9RwCBjf0rg X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-05-28_05,2025-05-27_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 spamscore=0 bulkscore=0 priorityscore=1501 adultscore=0 lowpriorityscore=0 suspectscore=0 phishscore=0 malwarescore=0 clxscore=1015 mlxscore=0 mlxlogscore=802 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505160000 definitions=main-2505280082 All paths leading to handle_essa() already hold the kvm->srcu. Remove unneeded srcu locking from handle_essa(). Add lockdep assertion to make sure we will always be holding kvm->srcu when entering handle_essa(). Signed-off-by: Claudio Imbrenda Reviewed-by: Nina Schoetterl-Glausch Reviewed-by: Christian Borntraeger Reviewed-by: Christoph Schlameuss Reviewed-by: Steffen Eiden --- arch/s390/kvm/priv.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 1a49b89706f8..9253c70897a8 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -1248,6 +1248,8 @@ static inline int __do_essa(struct kvm_vcpu *vcpu, const int orc) static int handle_essa(struct kvm_vcpu *vcpu) { + lockdep_assert_held(&vcpu->kvm->srcu); + /* entries expected to be 1FF */ int entries = (vcpu->arch.sie_block->cbrlo & ~PAGE_MASK) >> 3; unsigned long *cbrlo; @@ -1297,12 +1299,8 @@ static int handle_essa(struct kvm_vcpu *vcpu) /* Retry the ESSA instruction */ kvm_s390_retry_instr(vcpu); } else { - int srcu_idx; - mmap_read_lock(vcpu->kvm->mm); - srcu_idx = srcu_read_lock(&vcpu->kvm->srcu); i = __do_essa(vcpu, orc); - srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx); mmap_read_unlock(vcpu->kvm->mm); if (i < 0) return i; -- 2.49.0