On Mon, Jun 10 2019 at 5:07am -0400, Pankaj Gupta <pagu...@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 <pagu...@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 350cf0451456..c5160d846fe6 100644 > --- a/drivers/md/dm-table.c > +++ b/drivers/md/dm-table.c > @@ -890,10 +890,17 @@ static int device_supports_dax(struct dm_target *ti, > struct dm_dev *dev, > start, len); > } > > +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); > +} > + > bool dm_table_supports_dax(struct dm_table *t, int blocksize) > { > 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++) { > @@ -906,7 +913,14 @@ bool dm_table_supports_dax(struct dm_table *t, int > blocksize) > !ti->type->iterate_devices(ti, device_supports_dax, > &blocksize)) > return false; > + > + /* Check devices support synchronous DAX */ > + if (dax_sync && > + !ti->type->iterate_devices(ti, device_synchronous, NULL)) > + dax_sync = false; > } > + if (dax_sync) > + set_dax_synchronous(t->md->dax_dev); > > return true; > } > -- > 2.20.1 > dm_table_supports_dax() is called multiple times (from dm_table_set_restrictions and dm_table_determine_type). It is strange to have a getter have a side-effect of being a setter too. Overloading like this could get you in trouble in the future. Are you certain this is what you want? Or would it be better to refactor dm_table_supports_dax() to take an iterate_devices_fn arg and have callers pass the appropriate function? Then have dm_table_set_restrictions() caller do: if (dm_table_supports_dax(t, device_synchronous, NULL)) set_dax_synchronous(t->md->dax_dev); (NULL arg implies dm_table_supports_dax() refactoring would take a int *data pointer rather than int type). Mike _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm