On Tue, May 02 2017 at 11:33pm -0400, Nicholas A. Bellinger <nab@xxxxxxxxxxxxxxx> wrote: > On Tue, 2017-05-02 at 09:23 +0200, hch@xxxxxx 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?