On Wed, Nov 12, 2014 at 11:04:23PM +0800, Chen Gang wrote: > When mutex_trylock() fails, kvm_vgic_create() will not create 'vgic', so > it need return failure code '-EBUSY' instead of '0' to let outside know > about it. I already sent a patch for the -EBUSY: https://lists.cs.columbia.edu/pipermail/kvmarm/2014-November/011936.html > > Also simplify the code within kvm_vgic_create(): > > - kvm_for_each_vcpu() scanning once is enough for current case. > > - Remove redundant variable 'vcpu_lock_idx'. I don't like using the iterator variable for this kind of thing because it can really break in languages where i is out-of-scope after the loop and it is too easy to reuse the iterator variable in later versions of the code. That being said, the scanning once is slightly prettier I guess, but I'd rather not introduce the churn unless others (Marc) think this is a big win. -Christoffer > > > Signed-off-by: Chen Gang <gang.chen.5i5j@xxxxxxxxx> > --- > virt/kvm/arm/vgic.c | 15 +++++++-------- > 1 file changed, 7 insertions(+), 8 deletions(-) > > diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c > index 3aaca49..5846725 100644 > --- a/virt/kvm/arm/vgic.c > +++ b/virt/kvm/arm/vgic.c > @@ -1933,7 +1933,7 @@ out: > > int kvm_vgic_create(struct kvm *kvm) > { > - int i, vcpu_lock_idx = -1, ret = 0; > + int i, ret = 0; > struct kvm_vcpu *vcpu; > > mutex_lock(&kvm->lock); > @@ -1949,13 +1949,12 @@ int kvm_vgic_create(struct kvm *kvm) > * that no other VCPUs are run while we create the vgic. > */ > kvm_for_each_vcpu(i, vcpu, kvm) { > - if (!mutex_trylock(&vcpu->mutex)) > + if (!mutex_trylock(&vcpu->mutex)) { > + ret = -EBUSY; > goto out_unlock; > - vcpu_lock_idx = i; > - } > - > - kvm_for_each_vcpu(i, vcpu, kvm) { > + } > if (vcpu->arch.has_run_once) { > + mutex_unlock(&vcpu->mutex); > ret = -EBUSY; > goto out_unlock; > } > @@ -1968,8 +1967,8 @@ int kvm_vgic_create(struct kvm *kvm) > kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF; > > out_unlock: > - for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) { > - vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx); > + while (i-- > 0) { > + vcpu = kvm_get_vcpu(kvm, i); > mutex_unlock(&vcpu->mutex); > } > > -- > 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
