[PATCH 3.4 20/25] KVM: return an error code in kvm_vm_ioctl_register_coalesced_mmio()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@oracle.com>

commit aac5c4226e7136c331ed384c25d5560204da10a0 upstream.

If kvm_io_bus_register_dev() fails then it returns success but it should
return an error code.

I also did a little cleanup like removing an impossible NULL test.

Fixes: 2b3c246a682c ('KVM: Make coalesced mmio use a device per zone')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 virt/kvm/coalesced_mmio.c |    8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -154,17 +154,13 @@ int kvm_vm_ioctl_register_coalesced_mmio
 	list_add_tail(&dev->list, &kvm->coalesced_zones);
 	mutex_unlock(&kvm->slots_lock);
 
-	return ret;
+	return 0;
 
 out_free_dev:
 	mutex_unlock(&kvm->slots_lock);
-
 	kfree(dev);
 
-	if (dev == NULL)
-		return -ENXIO;
-
-	return 0;
+	return ret;
 }
 
 int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,