From: Claudio Imbrenda Date: Wed, 28 May 2025 09:55:00 +0000 (+0200) Subject: KVM: s390: Remove unneeded srcu lock X-Git-Tag: v6.16-rc1~78^2~2^2~2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7e42ad66fb5d0902b1f8d4d9a8fee898b685046a;p=thirdparty%2Fkernel%2Fstable.git KVM: s390: Remove unneeded srcu lock 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(). Reviewed-by: Nina Schoetterl-Glausch Reviewed-by: Christian Borntraeger Reviewed-by: Christoph Schlameuss Reviewed-by: Steffen Eiden Link: https://lore.kernel.org/r/20250528095502.226213-3-imbrenda@linux.ibm.com Signed-off-by: Claudio Imbrenda Message-ID: <20250528095502.226213-3-imbrenda@linux.ibm.com> --- diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 1a49b89706f86..9253c70897a8d 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;