[Drbd-dev] [PATCH 25/27] block: remove the discard_zeroes_data flag

[Nicholas A. Bellinger]

On Wed, 2017-05-03 at 10:33 -0400, Mike Snitzer wrote:
> On Tue, May 02 2017 at 11:33pm -0400,
> Nicholas A. Bellinger <nab at linux-iscsi.org> wrote:
> 
> > On Tue, 2017-05-02 at 09:23 +0200, hch at lst.de wrote:
> > > On Tue, May 02, 2017 at 12:16:13AM -0700, Nicholas A. Bellinger wrote:
> > > > Or, another options is use bdev_write_zeroes_sectors() to determine when
> > > > dev_attrib->unmap_zeroes_data should be set.
> > > 
> > > Yes, that in combination with your patch to use bdev_write_zeroes_sectors
> > > for zeroing from write same seems like the right fix.
> > 
> > The larger target/iblock conversion patch looks like post v4.12 material
> > at this point, so to avoid breakage wrt to existing LBPRZ behavior, I'll
> > plan to push the following patch post -rc1.
> > 
> > diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
> > index d2f089c..e7caf78 100644
> > --- a/drivers/target/target_core_device.c
> > +++ b/drivers/target/target_core_device.c
> > @@ -851,7 +851,7 @@ bool target_configure_unmap_from_queue(struct se_dev_attrib *attrib,
> >         attrib->unmap_granularity = q->limits.discard_granularity / block_size;
> >         attrib->unmap_granularity_alignment = q->limits.discard_alignment /
> >                                                                 block_size;
> > -       attrib->unmap_zeroes_data = 0;
> > +       attrib->unmap_zeroes_data = (q->limits.max_write_zeroes_sectors);
> >         return true;
> >  }
> >  EXPORT_SYMBOL(target_configure_unmap_from_queue);
> > 
> 
> Completely a nit but: why the extra parenthesis?

dev_attrib->unmap_zeros_data is only compared as a bool.