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Tue, 20 May 2025 18:26:40 +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 v2 2/5] KVM: s390: remove unneeded srcu lock Date: Tue, 20 May 2025 20:26:36 +0200 Message-ID: <20250520182639.80013-3-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250520182639.80013-1-imbrenda@linux.ibm.com> References: <20250520182639.80013-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@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=Va/3PEp9 c=1 sm=1 tr=0 ts=682cc966 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=dt9VzEwgFbYA:10 a=VnNF1IyMAAAA:8 a=-g0RikXFz7zMAnJmuvsA:9 X-Proofpoint-GUID: 7h3B5V7Jb0CLBNNFLTMCs3H_T-wx95jo X-Proofpoint-ORIG-GUID: 7h3B5V7Jb0CLBNNFLTMCs3H_T-wx95jo X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNTIwMDE1MCBTYWx0ZWRfXxk7Iq5jpT34J VRbiNh79Un0s8p5T3QXvx1gs8Frv5NqkC/EIa524fvS3Or5QN4GMJIvJOHNBemGqunom3Ao9BVn cPwYQXg/Y+ZHBhCxqhtfZcYCTZkQWc7V+26CLgKKLDwpGxlFjlpZAC3cGqn7XkCwYx29JZcj2UV TuZecWGgbajM9F9TVhqCODOmWe21NesYM4GCr5NFgxPj/5AJ74s6IX4fDEUzii7/E/bxez7nvA6 1XSPu3zX/Rsm4RPKO7dpFk7bf70Ub7LGwJYX/yQ0u2EsbWSkg9svY7sBXfVZTfchSgvcebK8OEZ EB7pjmY5Dbu/kjAf/gW7BmLSygSikSjGWHvH20hOT3/ZMAmeG40Mh1zJHwzcWGqnGDSBZXzZeIi Ji2xMPewagj9W7EL5mkckLgBzl6p7YJHOYMERZLxSn3041h3cwLsd8GMRi2SUQc/gRDgimE9 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=2025-05-20_08,2025-05-20_03,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 bulkscore=0 impostorscore=0 mlxlogscore=770 clxscore=1015 phishscore=0 suspectscore=0 spamscore=0 adultscore=0 priorityscore=1501 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505160000 definitions=main-2505200150 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 --- 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