On 05/25/2018 01:25 AM, Fam Zheng wrote:
And that makes five labels in total, I'm not sure I like it:
fail_handler:
aio_set_event_notifier(bdrv_get_aio_context(bs), &s->irq_notifier,
false, NULL, NULL);
fail_queue:
nvme_free_queue_pair(bs, s->queues[0]);
fail_regs:
qemu_vfio_pci_unmap_bar(s->vfio, 0, (void *)s->regs, 0, NVME_BAR_SIZE);
fail_vfio:
qemu_vfio_close(s->vfio);
fail:
g_free(s->queues);
event_notifier_cleanup(&s->irq_notifier);
return ret;
Doesn't look materially worse to me :)
The labels themselves are not ugly or bad, but the goto statements above will be
harder to manage.
With nice cleanup functions that detect "hasn't been set up" and do
nothing then, like free(NULL), you can use just one label. Sadly,
cleanup functions are often not nice that way.
nvme_free_queue_pair and qemu_vfio_close are cleanup functions and we can
improve them, but to make qemu_vfio_pci_unmap_bar behave similarly is just odd:
it's not a clean up function, at least not for s->vfio.
But even then, you can do:
fail:
if (s->vfio) {
qemu_vfio_close(s->vfio);
}
That is, there are ways to make a single cleanup path more applicable,
regardless of where you decided you needed an early cleanup.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
