Re: [PATCH 2/3] nfit, libnvdimm: allow an ARS rescan to be triggered on demand

On 07/19, Dan Williams wrote: > On Mon, Jul 18, 2016 at 5:44 PM, Vishal Verma <vishal.l.verma(a)intel.com&gt; wrote: > > Normally, an ARS (Address Range Scrub) only happens at > > boot/initialization time. There can however arise situations where a > > bus-wide rescan is needed - notably, in the case of discovering a latent > > media error, we should do a full rescan to figure out what other sectors > > are bad, and thus potentially avoid triggering an mce on them in the > > future. Also provide a sysfs trigger to start a bus-wide rescan. > > > > Cc: Dan Williams <dan.j.williams(a)intel.com&gt; > > Cc: Rafael J. Wysocki <rafael.j.wysocki(a)intel.com&gt; > > Cc: <linux-acpi(a)vger.kernel.org&gt; > > Cc: <linux-nvdimm(a)lists.01.org&gt; > > Signed-off-by: Vishal Verma <vishal.l.verma(a)intel.com&gt; > > --- > > drivers/acpi/nfit.c | 36 ++++++++++++++++++++++++++++++++---- > > drivers/acpi/nfit.h | 1 + > > drivers/nvdimm/core.c | 17 +++++++++++++++++ > > include/linux/libnvdimm.h | 1 + > > 4 files changed, 51 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c > > index ac6ddcc0..def9505 100644 > > --- a/drivers/acpi/nfit.c > > +++ b/drivers/acpi/nfit.c > > @@ -2138,8 +2138,9 @@ static void acpi_nfit_async_scrub(struct acpi_nfit_desc *acpi_desc, > > unsigned int tmo = scrub_timeout; > > int rc; > > > > - if (nfit_spa->ars_done || !nfit_spa->nd_region) > > - return; > > + if (!nfit_spa->ars_rescan) > > + if (nfit_spa->ars_done || !nfit_spa->nd_region) > > + return; > > Do we need a new flag? Why not just clear ->ars_done? This is what I had started out with - clearing the done flag, but the done flag gets set at the end of acpi_nfit_scrub if a region has been registered for that SPA. In the rescan case, we'll almost always have our regions registered, so the done flag will get set here, and acpi_nfit_async_scrub won't look at it at all..