Am 03.07.2014 um 11:51 hat Ming Lei geschrieben:
> Hi Kevin,
>
> On Thu, Jul 3, 2014 at 5:40 PM, Kevin Wolf <kw...@redhat.com> wrote:
> > Am 02.07.2014 um 14:18 hat Ming Lei geschrieben:
> >> This patch implements .bdrv_io_plug, .bdrv_io_unplug and
> >> .bdrv_flush_io_queue callbacks for linux-aio Block Drivers,
> >> so that submitting I/O as a batch can be supported on linux-aio.
> >>
> >> Signed-off-by: Ming Lei <ming....@canonical.com>
> >
> > Just a couple of minor comments, see inline.
>
> Thanks for your review.
>
> >> +void laio_io_plug(BlockDriverState *bs, void *aio_ctx)
> >> +{
> >> + struct qemu_laio_state *s = aio_ctx;
> >> +
> >> + s->io_q.plugged++;
> >> +}
> >> +
> >> +int laio_io_unplug(BlockDriverState *bs, void *aio_ctx, bool unplug)
> >> +{
> >> + struct qemu_laio_state *s = aio_ctx;
> >> + int ret = 0;
> >> +
> >
> > How about an assert(s->io_q.plugged > 0); here?
>
> how about just adding a warning because flush io queue uses
> the function too?
Good point, this is what the assertion should look like then:
assert(s->io_q.plugged > 0 || !unplug);
> Also that is why 'plugged' is defined as signed.
I don't understand. The flush function leaves s->io_q.plugged alone
(otherwise it would be buggy), so how can it ever become negative? And
if you say that a negative value is valid, what would it even mean?
> >
> >> + if (unplug && --s->io_q.plugged > 0)
> >> + return 0;
> >
> > Missing braces.
> >
> >> +
> >> + if (s->io_q.idx > 0) {
> >> + ret = ioq_submit(s);
> >> + }
> >> +
> >> + return ret;
> >> +}
Kevin
