Re: [PATCH 08/17] hw/block/nvme: refactor aio submission

[Keith Busch]

On Fri, Sep 04, 2020 at 10:38:39PM +0200, Klaus Jensen wrote:
> On Sep  4 12:47, Keith Busch wrote:
> > On Fri, Sep 04, 2020 at 04:19:47PM +0200, Klaus Jensen wrote:
> > > diff --git a/hw/block/nvme.c b/hw/block/nvme.c
> > > index bfac3385cb64..3e32f39c7c1d 100644
> > > --- a/hw/block/nvme.c
> > > +++ b/hw/block/nvme.c
> > > @@ -110,6 +110,7 @@ static const uint32_t nvme_feature_cap[NVME_FID_MAX] 
> > > = {
> > >  };
> > >  
> > >  static void nvme_process_sq(void *opaque);
> > > +static void nvme_aio_cb(void *opaque, int ret);
> > 
> > You don't need the forward declaration here. Just move the
> > implementation above where it's used. It looks safe: nvme_aio_cb()
> > doesn't have any circular dependencies.
> 
> You are right, of course. But it is getting a circular dependency in a
> later patch. I left it there to reduce code movement later.

Is that coming in a future patch? Not finding it in this series.

About the whole patch in general, are multiple aio's per-request coming
in later patch as well? I didn't see any use for it here, and the
overhead of dynamic allocation and zeroing a new struct in the IO path
is a bit concerning for performance. I'd like to see your intended use
for this.