Re: [Qemu-devel] [PATCH v10 4/7] dm: enable synchronous dax

[Pankaj Gupta <pagupta@redhat.com>]

> On Tue, May 21, 2019 at 6:43 AM Pankaj Gupta <pagupta@redhat.com> wrote:
> >
> >  This patch sets dax device 'DAXDEV_SYNC' flag if all the target
> >  devices of device mapper support synchrononous DAX. If device
> >  mapper consists of both synchronous and asynchronous dax devices,
> >  we don't set 'DAXDEV_SYNC' flag.
> >
> > Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
> > ---
> >  drivers/md/dm-table.c | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >
> > diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> > index cde3b49b2a91..1cce626ff576 100644
> > --- a/drivers/md/dm-table.c
> > +++ b/drivers/md/dm-table.c
> > @@ -886,10 +886,17 @@ static int device_supports_dax(struct dm_target *ti,
> > struct dm_dev *dev,
> >         return bdev_dax_supported(dev->bdev, PAGE_SIZE);
> >  }
> >
> > +static int device_synchronous(struct dm_target *ti, struct dm_dev *dev,
> > +                              sector_t start, sector_t len, void *data)
> > +{
> > +       return dax_synchronous(dev->dax_dev);
> > +}
> > +
> >  static bool dm_table_supports_dax(struct dm_table *t)
> >  {
> >         struct dm_target *ti;
> >         unsigned i;
> > +       bool dax_sync = true;
> >
> >         /* Ensure that all targets support DAX. */
> >         for (i = 0; i < dm_table_get_num_targets(t); i++) {
> > @@ -901,7 +908,14 @@ static bool dm_table_supports_dax(struct dm_table *t)
> >                 if (!ti->type->iterate_devices ||
> >                     !ti->type->iterate_devices(ti, device_supports_dax,
> >                     NULL))
> >                         return false;
> > +
> > +               /* Check devices support synchronous DAX */
> > +               if (dax_sync &&
> > +                   !ti->type->iterate_devices(ti, device_synchronous,
> > NULL))
> > +                       dax_sync = false;
> 
> Looks like this needs to be rebased on the current state of v5.2-rc,
> and then we can nudge Mike for an ack.

Sorry! for late reply due to vacations. I will rebase the series on v5.2-rc4 and
send a v11.

Thanks,
Pankaj
Yes, 
>