[PATCH] virt: kvm: arm: vgic: Return failure code '-EBUSY' when mutex_trylock() fails

Chen Gang
2014-11-12T15:04:23Z

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.5i5j@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