Re: [Qemu-devel] [PATCH v2 3/6] block: Add VFIO based NVMe driver

[Fam Zheng <famz@redhat.com>]

On Thu, 02/23 10:43, Paolo Bonzini wrote:
> 
> 
> On 23/02/2017 10:18, Fam Zheng wrote:
> > +    for (i = 0; i < s->nr_queues; ++i) {
> > +        s->queues[i]->free_req_queue_bh =
> > +            aio_bh_new(new_context, nvme_free_req_queue_cb, s->queues[i]);
> > +    }
> 
> aio_bh_new has the issue that you can complete two requests in one
> nvme_process_completion call, but you would only invoke the bottom half
> once.  Because this is a rare event, I think it's enough to use
> aio_bh_schedule_oneshot instead of aio_bh_new.

Yes, that should work.

> 
> > +static coroutine_fn int nvme_cmd_unmap_qiov(BlockDriverState *bs,
> > +                                            QEMUIOVector *qiov)
> > +{
> > +    int r = 0;
> > +    BDRVNVMeState *s = bs->opaque;
> > +
> > +    if (!s->inflight && !qemu_co_queue_empty(&s->dma_flush_queue)) {
> > +        r = nvme_vfio_dma_reset_temporary(s->vfio);
> > +        qemu_co_queue_next(&s->dma_flush_queue);
> > +    }
> > +    return r;
> > +}
> 
> Should this be qemu_co_queue_restart_all instead?

You are right, will fix!

Fam