On 07/19, Dan Williams wrote: > On Mon, Jul 18, 2016 at 5:44 PM, Vishal Verma <vishal.l.verma@xxxxxxxxx> 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@xxxxxxxxx> > > Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > Cc: <linux-acpi@xxxxxxxxxxxxxxx> > > Cc: <linux-nvdimm@xxxxxxxxxxxx> > > Signed-off-by: Vishal Verma <vishal.l.verma@xxxxxxxxx> > > --- > > 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.. > > > > > rc = ars_start(acpi_desc, nfit_spa); > > /* > > @@ -2227,7 +2228,9 @@ static void acpi_nfit_scrub(struct work_struct *work) > > * firmware initiated scrubs to complete and then we go search for the > > * affected spa regions to mark them scanned. In the second phase we > > * initiate a directed scrub for every range that was not scrubbed in > > - * phase 1. > > + * phase 1. If we're called for a 'rescan', we harmlessly pass through > > + * the first phase, but really only care about running phase 2, where > > + * regions can be notified of new poison. > > */ > > I don't think we need to distinguish the initial scan case from the > re-scan case in acpi_nfit_scrub(). Whether it's a scan or a re-scan > doesn't matter to acpi_nfit_scrub(). Right, other than the above flag, we don't really distinguish betweent the two. The comment was just a clarification/note that nothing meaningful happens in this function for the rescan case. > > > > > /* process platform firmware initiated scrubs */ > > @@ -2336,8 +2339,10 @@ static void acpi_nfit_scrub(struct work_struct *work) > > acpi_nfit_register_region(acpi_desc, nfit_spa); > > } > > > > - list_for_each_entry(nfit_spa, &acpi_desc->spas, list) > > + list_for_each_entry(nfit_spa, &acpi_desc->spas, list) { > > acpi_nfit_async_scrub(acpi_desc, nfit_spa); > > + nfit_spa->ars_rescan = 0; > > + } > > mutex_unlock(&acpi_desc->init_mutex); > > } > > > > @@ -2495,6 +2500,28 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc, > > return 0; > > } > > > > +static int acpi_nfit_ars_rescan(struct nvdimm_bus_descriptor *nd_desc) > > +{ > > + struct acpi_nfit_desc *acpi_desc = to_acpi_nfit_desc(nd_desc); > > + struct device *dev = acpi_desc->dev; > > + struct nfit_spa *nfit_spa; > > + > > + if (work_busy(&acpi_desc->work)) > > + return -EBUSY; > > How does userspace figure out when the queue is not busy? See below > in the notes about the ars_rescan attribute. > > > + > > + list_for_each_entry(nfit_spa, &acpi_desc->spas, list) { > > + struct acpi_nfit_system_address *spa = nfit_spa->spa; > > + > > + if (nfit_spa_type(spa) != NFIT_SPA_PM) > > + continue; > > + > > + nfit_spa->ars_rescan = 1; > > + } > > + queue_work(nfit_wq, &acpi_desc->work); > > + dev_info(dev, "%s: ars_rescan triggered\n", __func__); > > + return 0; > > +} > > + > > void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev) > > { > > struct nvdimm_bus_descriptor *nd_desc; > > @@ -2507,6 +2534,7 @@ void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev) > > nd_desc->ndctl = acpi_nfit_ctl; > > nd_desc->flush_probe = acpi_nfit_flush_probe; > > nd_desc->clear_to_send = acpi_nfit_clear_to_send; > > + nd_desc->ars_rescan = acpi_nfit_ars_rescan; > > nd_desc->attr_groups = acpi_nfit_attribute_groups; > > > > INIT_LIST_HEAD(&acpi_desc->spa_maps); > > diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h > > index 02b9ea1..db95c5d 100644 > > --- a/drivers/acpi/nfit.h > > +++ b/drivers/acpi/nfit.h > > @@ -78,6 +78,7 @@ struct nfit_spa { > > struct list_head list; > > struct nd_region *nd_region; > > unsigned int ars_done:1; > > + unsigned int ars_rescan:1; > > u32 clear_err_unit; > > u32 max_ars; > > }; > > diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c > > index be89764..54f6fd5 100644 > > --- a/drivers/nvdimm/core.c > > +++ b/drivers/nvdimm/core.c > > @@ -313,10 +313,27 @@ static ssize_t wait_probe_show(struct device *dev, > > } > > static DEVICE_ATTR_RO(wait_probe); > > > > +static ssize_t ars_rescan_store(struct device *dev, > > + struct device_attribute *attr, const char *buf, size_t size) > > +{ > > + struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev); > > + struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc; > > + int rc; > > + > > + if (nd_desc->ars_rescan) { > > + rc = nd_desc->ars_rescan(nd_desc); > > + if (rc) > > + return rc; > > + } > > + return size; > > +} > > +static DEVICE_ATTR_WO(ars_rescan); > > A few notes: > > 1/ ARS is unique to the nfit driver so let's make this nfit specific, > i.e. add it to acpi_nfit_attribute_group. > > 2/ Let's just call the attribute scrub and not distinguish it as "re-" > > 3/ Userspace may want to know when scanning is complete so let's make > this attribute read/write and on read return a count of the number of > completed scans since the driver was loaded. For notification of last > completion use sysfs_notify_dirent_safe() to make this scrub attribute > select()/poll() capable. Ok, sounds reasonable. > > > + > > static struct attribute *nvdimm_bus_attributes[] = { > > &dev_attr_commands.attr, > > &dev_attr_wait_probe.attr, > > &dev_attr_provider.attr, > > + &dev_attr_ars_rescan.attr, > > NULL, > > }; > > > > diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h > > index 0c3c30c..1c6867a 100644 > > --- a/include/linux/libnvdimm.h > > +++ b/include/linux/libnvdimm.h > > @@ -74,6 +74,7 @@ struct nvdimm_bus_descriptor { > > int (*flush_probe)(struct nvdimm_bus_descriptor *nd_desc); > > int (*clear_to_send)(struct nvdimm_bus_descriptor *nd_desc, > > struct nvdimm *nvdimm, unsigned int cmd); > > + int (*ars_rescan)(struct nvdimm_bus_descriptor *nd_desc); > > }; > > > > struct nd_cmd_desc { > > -- > > 2.7.4 > > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html