KVM: PPC: Decrement module refcount if init_vm fails

We increment the reference count for KVM-HV/PR before the call to
kvmppc_core_init_vm. If that function fails we need to decrement the
refcount.

Also remove the check on kvm_ops->owner because try_module_get can
handle a NULL module.

Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220125155735.1018683-5-farosas@linux.ibm.com

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 1d06b68..9772b17 100644 (file)
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -453,6 +453,8 @@ int kvm_arch_check_processor_compat(void *opaque)
 int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 {
        struct kvmppc_ops *kvm_ops = NULL;
+       int r;
+
        /*
         * if we have both HV and PR enabled, default is HV
         */
@@ -474,11 +476,14 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
        } else
                goto err_out;
 
-       if (kvm_ops->owner && !try_module_get(kvm_ops->owner))
+       if (!try_module_get(kvm_ops->owner))
                return -ENOENT;
 
        kvm->arch.kvm_ops = kvm_ops;
-       return kvmppc_core_init_vm(kvm);
+       r = kvmppc_core_init_vm(kvm);
+       if (r)
+               module_put(kvm_ops->owner);
+       return r;
 err_out:
        return -EINVAL;
 }