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.

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'.


Signed-off-by: Chen Gang <gang.chen.5...@gmail.com>
---
 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
--
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