[PATCH 6/8] nfit: scrub and register regions in a workqueue

[Dan Williams <dan.j.williams@intel.com>]

Address range scrub is a potentially long running process that we want
to complete before any pmem regions are registered.  Perform this
operation asynchronously to allow other drivers to load in the meantime.

Platform firmware may have initiated a partial scrub prior to the driver
loading, so we must be careful to consume those results before kicking
off kernel initiated scrubs on other regions.

This rework also makes the registration path more tolerant of scrub
errors in that it splits scrubbing into 2 phases.  The first phase
synchronously waits for a platform-firmware initiated scrub to complete.
The second phase scans the remaining address ranges asynchronously and
notifies the related driver(s) when the scrub completes.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/acpi/nfit.c |  539 +++++++++++++++++++++++++++++++++++----------------
 drivers/acpi/nfit.h |    8 +
 2 files changed, 372 insertions(+), 175 deletions(-)

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index 4aa2bd54fc1d..8e6a82e7a87f 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -21,6 +21,7 @@
 #include <linux/sort.h>
 #include <linux/pmem.h>
 #include <linux/io.h>
+#include <linux/nd.h>
 #include <asm/cacheflush.h>
 #include "nfit.h"
 
@@ -34,6 +35,16 @@ static bool force_enable_dimms;
 module_param(force_enable_dimms, bool, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(force_enable_dimms, "Ignore _STA (ACPI DIMM device) status");
 
+static unsigned int scrub_timeout = NFIT_ARS_TIMEOUT;
+module_param(scrub_timeout, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(scrub_timeout, "Initial scrub timeout in seconds");
+
+/* after three payloads of overflow, it's dead jim */
+static unsigned int scrub_overflow_abort = 3;
+module_param(scrub_overflow_abort, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(scrub_overflow_abort,
+		"Number of times we overflow ARS results before abort");
+
 static struct workqueue_struct *nfit_wq;
 
 struct nfit_table_prev {
@@ -1548,97 +1559,84 @@ static void acpi_nfit_blk_region_disable(struct nvdimm_bus *nvdimm_bus,
 }
 
 static int ars_get_cap(struct acpi_nfit_desc *acpi_desc,
-		struct nd_cmd_ars_cap *cmd, u64 addr, u64 length)
+		struct nd_cmd_ars_cap *cmd, struct nfit_spa *nfit_spa)
 {
 	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
 	int cmd_rc, rc;
 
-	cmd->address = addr;
-	cmd->length = length;
+	cmd->address = spa->address;
+	cmd->length = spa->length;
 	rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_CAP, cmd,
 			sizeof(*cmd), &cmd_rc);
 	if (rc < 0)
 		return rc;
-	if (cmd_rc < 0)
-		return cmd_rc;
-	return 0;
+	return cmd_rc;
 }
 
-static int ars_do_start(struct nvdimm_bus_descriptor *nd_desc,
-		struct nd_cmd_ars_start *cmd, u64 addr, u64 length)
+static int ars_start(struct acpi_nfit_desc *acpi_desc, struct nfit_spa *nfit_spa)
 {
-	int cmd_rc;
 	int rc;
+	int cmd_rc;
+	struct nd_cmd_ars_start ars_start;
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
+	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
 
-	cmd->address = addr;
-	cmd->length = length;
-	cmd->type = ND_ARS_PERSISTENT;
-
-	while (1) {
-		rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_START, cmd,
-				sizeof(*cmd), &cmd_rc);
-
-		if (rc < 0)
-			return rc;
-
-		if (cmd_rc == -EBUSY) {
-			/* ARS is in progress */
-			msleep(1000);
-			continue;
-		}
+	memset(&ars_start, 0, sizeof(ars_start));
+	ars_start.address = spa->address;
+	ars_start.length = spa->length;
+	if (nfit_spa_type(spa) == NFIT_SPA_PM)
+		ars_start.type = ND_ARS_PERSISTENT;
+	else if (nfit_spa_type(spa) == NFIT_SPA_VOLATILE)
+		ars_start.type = ND_ARS_VOLATILE;
+	else
+		return -ENOTTY;
 
-		if (cmd_rc < 0)
-			return cmd_rc;
+	rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_START, &ars_start,
+			sizeof(ars_start), &cmd_rc);
 
-		return 0;
-	}
+	if (rc < 0)
+		return rc;
+	return cmd_rc;
 }
 
-static int ars_get_status(struct nvdimm_bus_descriptor *nd_desc,
-		struct nd_cmd_ars_status *cmd, u32 size)
+static int ars_continue(struct acpi_nfit_desc *acpi_desc)
 {
 	int rc, cmd_rc;
+	struct nd_cmd_ars_start ars_start;
+	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
+	struct nd_cmd_ars_status *ars_status = acpi_desc->ars_status;
+
+	memset(&ars_start, 0, sizeof(ars_start));
+	ars_start.address = ars_status->restart_address;
+	ars_start.length = ars_status->restart_length;
+	ars_start.type = ars_status->type;
+	rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_START, &ars_start,
+			sizeof(ars_start), &cmd_rc);
+	if (rc < 0)
+		return rc;
+	return cmd_rc;
+}
 
-	while (1) {
-		rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_STATUS, cmd,
-			size, &cmd_rc);
-		if (rc < 0)
-			return rc;
-
-		/* FIXME make async and have a timeout */
-		if (cmd_rc == -EBUSY) {
-			msleep(1000);
-			continue;
-		}
-
-		if (cmd_rc == -EAGAIN || cmd_rc == 0)
-			return 0;
-
-		/* TODO: error list overflow support */
-		if (cmd_rc == -ENOSPC)
-			return -ENXIO;
-
-		return cmd_rc;
-	}
+static int ars_get_status(struct acpi_nfit_desc *acpi_desc)
+{
+	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
+	struct nd_cmd_ars_status *ars_status = acpi_desc->ars_status;
+	int rc, cmd_rc;
+	
+	rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_STATUS, ars_status,
+			acpi_desc->ars_status_size, &cmd_rc);
+	if (rc < 0)
+		return rc;
+	return cmd_rc;
 }
 
 static int ars_status_process_records(struct nvdimm_bus *nvdimm_bus,
-		struct nd_cmd_ars_status *ars_status, u64 start)
+		struct nd_cmd_ars_status *ars_status)
 {
 	int rc;
 	u32 i;
 
-	/*
-	 * The address field returned by ars_status should be either
-	 * less than or equal to the address we last started ARS for.
-	 * The (start, length) returned by ars_status should also have
-	 * non-zero overlap with the range we started ARS for.
-	 * If this is not the case, bail.
-	 */
-	if (ars_status->address > start ||
-			(ars_status->address + ars_status->length < start))
-		return -ENXIO;
-
 	for (i = 0; i < ars_status->num_records; i++) {
 		rc = nvdimm_bus_add_poison(nvdimm_bus,
 				ars_status->records[i].err_address,
@@ -1650,101 +1648,14 @@ static int ars_status_process_records(struct nvdimm_bus *nvdimm_bus,
 	return 0;
 }
 
-static int acpi_nfit_find_poison(struct acpi_nfit_desc *acpi_desc,
-		struct nd_region_desc *ndr_desc)
-{
-	struct nvdimm_bus_descriptor *nd_desc = &acpi_desc->nd_desc;
-	struct nvdimm_bus *nvdimm_bus = acpi_desc->nvdimm_bus;
-	struct nd_cmd_ars_status *ars_status = NULL;
-	struct nd_cmd_ars_start *ars_start = NULL;
-	struct nd_cmd_ars_cap *ars_cap = NULL;
-	u64 start, len, cur, remaining;
-	u32 ars_status_size;
-	int rc;
-
-	ars_cap = kzalloc(sizeof(*ars_cap), GFP_KERNEL);
-	if (!ars_cap)
-		return -ENOMEM;
-
-	start = ndr_desc->res->start;
-	len = ndr_desc->res->end - ndr_desc->res->start + 1;
-
-	rc = ars_get_cap(acpi_desc, ars_cap, start, len);
-	if (rc == -ENOTTY) {
-		rc = 0;
-		goto out;
-	}
-
-	/*
-	 * Check if a full-range ARS has been run. If so, use those results
-	 * without having to start a new ARS.
-	 */
-	ars_status_size = ars_cap->max_ars_out;
-	ars_status = kzalloc(ars_status_size, GFP_KERNEL);
-	if (!ars_status) {
-		rc = -ENOMEM;
-		goto out;
-	}
-
-	rc = ars_get_status(nd_desc, ars_status, ars_status_size);
-	if (rc)
-		goto out;
-
-	if (ars_status->address <= start &&
-		(ars_status->address + ars_status->length >= start + len)) {
-		rc = ars_status_process_records(nvdimm_bus, ars_status, start);
-		goto out;
-	}
-
-	/*
-	 * ARS_STATUS can overflow if the number of poison entries found is
-	 * greater than the maximum buffer size (ars_cap->max_ars_out)
-	 * To detect overflow, check if the length field of ars_status
-	 * is less than the length we supplied. If so, process the
-	 * error entries we got, adjust the start point, and start again
-	 */
-	ars_start = kzalloc(sizeof(*ars_start), GFP_KERNEL);
-	if (!ars_start)
-		return -ENOMEM;
-
-	cur = start;
-	remaining = len;
-	do {
-		u64 done, end;
-
-		rc = ars_do_start(nd_desc, ars_start, cur, remaining);
-		if (rc < 0)
-			goto out;
-
-		rc = ars_get_status(nd_desc, ars_status, ars_status_size);
-		if (rc < 0)
-			goto out;
-
-		rc = ars_status_process_records(nvdimm_bus, ars_status, cur);
-		if (rc < 0)
-			goto out;
-
-		end = min(cur + remaining,
-			ars_status->address + ars_status->length);
-		done = end - cur;
-		cur += done;
-		remaining -= done;
-	} while (remaining);
-
- out:
-	kfree(ars_cap);
-	kfree(ars_start);
-	kfree(ars_status);
-	return rc;
-}
-
 static int acpi_nfit_init_mapping(struct acpi_nfit_desc *acpi_desc,
 		struct nd_mapping *nd_mapping, struct nd_region_desc *ndr_desc,
 		struct acpi_nfit_memory_map *memdev,
-		struct acpi_nfit_system_address *spa)
+		struct nfit_spa *nfit_spa)
 {
 	struct nvdimm *nvdimm = acpi_nfit_dimm_by_handle(acpi_desc,
 			memdev->device_handle);
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
 	struct nd_blk_region_desc *ndbr_desc;
 	struct nfit_mem *nfit_mem;
 	int blk_valid = 0;
@@ -1780,7 +1691,9 @@ static int acpi_nfit_init_mapping(struct acpi_nfit_desc *acpi_desc,
 		ndbr_desc->enable = acpi_nfit_blk_region_enable;
 		ndbr_desc->disable = acpi_nfit_blk_region_disable;
 		ndbr_desc->do_io = acpi_desc->blk_do_io;
-		if (!nvdimm_blk_region_create(acpi_desc->nvdimm_bus, ndr_desc))
+		nfit_spa->nd_region = nvdimm_blk_region_create(acpi_desc->nvdimm_bus,
+				ndr_desc);
+		if (!nfit_spa->nd_region)
 			return -ENOMEM;
 		break;
 	}
@@ -1800,7 +1713,7 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
 	struct resource res;
 	int count = 0, rc;
 
-	if (nfit_spa->is_registered)
+	if (nfit_spa->nd_region)
 		return 0;
 
 	if (spa->range_index == 0) {
@@ -1837,47 +1750,324 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
 		}
 		nd_mapping = &nd_mappings[count++];
 		rc = acpi_nfit_init_mapping(acpi_desc, nd_mapping, ndr_desc,
-				memdev, spa);
+				memdev, nfit_spa);
 		if (rc)
-			return rc;
+			goto out;
 	}
 
 	ndr_desc->nd_mapping = nd_mappings;
 	ndr_desc->num_mappings = count;
 	rc = acpi_nfit_init_interleave_set(acpi_desc, ndr_desc, spa);
 	if (rc)
-		return rc;
+		goto out;
 
 	nvdimm_bus = acpi_desc->nvdimm_bus;
 	if (nfit_spa_type(spa) == NFIT_SPA_PM) {
-		rc = acpi_nfit_find_poison(acpi_desc, ndr_desc);
-		if (rc) {
-			dev_err(acpi_desc->dev,
-				"error while performing ARS to find poison: %d\n",
-				rc);
-			return rc;
-		}
-		if (!nvdimm_pmem_region_create(nvdimm_bus, ndr_desc))
-			return -ENOMEM;
+		nfit_spa->nd_region = nvdimm_pmem_region_create(nvdimm_bus,
+				ndr_desc);
+		if (!nfit_spa->nd_region)
+			rc = -ENOMEM;
 	} else if (nfit_spa_type(spa) == NFIT_SPA_VOLATILE) {
-		if (!nvdimm_volatile_region_create(nvdimm_bus, ndr_desc))
-			return -ENOMEM;
+		nfit_spa->nd_region = nvdimm_volatile_region_create(nvdimm_bus,
+				ndr_desc);
+		if (!nfit_spa->nd_region)
+			rc = -ENOMEM;
 	}
 
-	nfit_spa->is_registered = 1;
+ out:
+	if (rc)
+		dev_err(acpi_desc->dev, "failed to register spa range %d\n",
+				nfit_spa->spa->range_index);
+	return rc;
+}
+
+static int ars_status_alloc(struct acpi_nfit_desc *acpi_desc,
+		u32 max_ars)
+{
+	struct device *dev = acpi_desc->dev;
+	struct nd_cmd_ars_status *ars_status;
+
+	if (acpi_desc->ars_status && acpi_desc->ars_status_size >= max_ars) {
+		memset(acpi_desc->ars_status, 0, acpi_desc->ars_status_size);
+		return 0;
+	}
+
+	if (acpi_desc->ars_status)
+		devm_kfree(dev, acpi_desc->ars_status);
+	acpi_desc->ars_status = NULL;
+	ars_status = devm_kzalloc(dev, max_ars, GFP_KERNEL);
+	if (!ars_status)
+		return -ENOMEM;
+	acpi_desc->ars_status = ars_status;
+	acpi_desc->ars_status_size = max_ars;
 	return 0;
 }
 
-static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
+static int acpi_nfit_query_poison(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_spa *nfit_spa)
+{
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
+	int rc;
+
+	if (!nfit_spa->max_ars) {
+		struct nd_cmd_ars_cap ars_cap;
+
+		memset(&ars_cap, 0, sizeof(ars_cap));
+		rc = ars_get_cap(acpi_desc, &ars_cap, nfit_spa);
+		if (rc < 0)
+			return rc;
+		nfit_spa->max_ars = ars_cap.max_ars_out;
+		nfit_spa->clear_err_unit = ars_cap.clear_err_unit;
+		/* check that the supported scrub types match the spa type */
+		if (nfit_spa_type(spa) == NFIT_SPA_VOLATILE &&
+				((ars_cap.status >> 16) & ND_ARS_VOLATILE) == 0)
+			return -ENOTTY;
+		else if (nfit_spa_type(spa) == NFIT_SPA_PM &&
+				((ars_cap.status >> 16) & ND_ARS_PERSISTENT) == 0)
+			return -ENOTTY;
+	}
+
+	if (ars_status_alloc(acpi_desc, nfit_spa->max_ars))
+		return -ENOMEM;
+
+	rc = ars_get_status(acpi_desc);
+	if (rc < 0 && rc != -ENOSPC)
+		return rc;
+
+	if (ars_status_process_records(acpi_desc->nvdimm_bus,
+				acpi_desc->ars_status))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void acpi_nfit_async_scrub(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_spa *nfit_spa)
+{
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
+	unsigned int overflow_retry = scrub_overflow_abort;
+	u64 init_ars_start = 0, init_ars_len = 0;
+	struct device *dev = acpi_desc->dev;
+	unsigned int tmo = scrub_timeout;
+	int rc;
+
+	if (nfit_spa->ars_done || !nfit_spa->nd_region)
+		return;
+
+	rc = ars_start(acpi_desc, nfit_spa);
+	/*
+	 * If we timed out the initial scan we'll still be busy here,
+	 * and will wait another timeout before giving up permanently.
+	 */
+	if (rc < 0 && rc != -EBUSY)
+		return;
+
+	do {
+		u64 ars_start, ars_len;
+
+		if (acpi_desc->cancel)
+			break;
+		rc = acpi_nfit_query_poison(acpi_desc, nfit_spa);
+		if (rc == -ENOTTY)
+			break;
+		if (rc == -EBUSY && !tmo) {
+			dev_warn(dev, "range %d ars timeout, aborting\n",
+					spa->range_index);
+			break;
+		}
+
+		if (rc == -EBUSY) {
+			/*
+			 * Note, entries may be appended to the list
+			 * while the lock is dropped, but the workqueue
+			 * being active prevents entries being deleted /
+			 * freed.
+			 */
+			mutex_unlock(&acpi_desc->init_mutex);
+			ssleep(1);
+			tmo--;
+			mutex_lock(&acpi_desc->init_mutex);
+			continue;
+		}
+
+		/* we got some results, but there are more pending... */
+		if (rc == -ENOSPC && overflow_retry--) {
+			if (!init_ars_len) {
+				init_ars_len = acpi_desc->ars_status->length;
+				init_ars_start = acpi_desc->ars_status->address;
+			}
+			rc = ars_continue(acpi_desc);
+		}
+
+		if (rc < 0) {
+			dev_warn(dev, "range %d ars continuation failed\n",
+					spa->range_index);
+			break;
+		}
+
+		if (init_ars_len) {
+			ars_start = init_ars_start;
+			ars_len = init_ars_len;
+		} else {
+			ars_start = acpi_desc->ars_status->address;
+			ars_len = acpi_desc->ars_status->length;
+		}
+		dev_dbg(dev, "spa range: %d ars from %#llx + %#llx complete\n",
+				spa->range_index, ars_start, ars_len);
+		/* notify the region about new poison entries */
+		nvdimm_region_notify(nfit_spa->nd_region,
+				NVDIMM_REVALIDATE_POISON);
+		break;
+	} while (1);
+}
+
+static void acpi_nfit_scrub(struct work_struct *work)
 {
+	struct device *dev;
+	u64 init_scrub_length = 0;
 	struct nfit_spa *nfit_spa;
+	u64 init_scrub_address = 0;
+	bool init_ars_done = false;
+	struct acpi_nfit_desc *acpi_desc;
+	unsigned int tmo = scrub_timeout;
+	unsigned int overflow_retry = scrub_overflow_abort;
+
+	acpi_desc = container_of(work, typeof(*acpi_desc), work);
+	dev = acpi_desc->dev;
 
+	/*
+	 * We scrub in 2 phases.  The first phase waits for any platform
+	 * 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.
+	 */
+
+	/* process platform firmware initiated scrubs */
+ retry:
+	mutex_lock(&acpi_desc->init_mutex);
 	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
-		int rc = acpi_nfit_register_region(acpi_desc, nfit_spa);
+		struct nd_cmd_ars_status *ars_status;
+		struct acpi_nfit_system_address *spa;
+		u64 ars_start, ars_len;
+		int rc;
 
-		if (rc)
-			return rc;
+		if (acpi_desc->cancel)
+			break;
+
+		if (nfit_spa->nd_region)
+			continue;
+
+		if (init_ars_done) {
+			/*
+			 * No need to re-query, we're now just
+			 * reconciling all the ranges covered by the
+			 * initial scrub
+			 */
+			rc = 0;
+		} else
+			rc = acpi_nfit_query_poison(acpi_desc, nfit_spa);
+
+		if (rc == -ENOTTY) {
+			/* no ars capability, just register spa and move on... */
+			acpi_nfit_register_region(acpi_desc, nfit_spa);
+			continue;
+		}
+
+		if (rc == -EBUSY && !tmo) {
+			/* fallthrough to directed scrub in phase 2 */
+			dev_warn(dev, "timeout awaiting ars results, continuing...\n");
+			break;
+		} else if (rc == -EBUSY) {
+			mutex_unlock(&acpi_desc->init_mutex);
+			ssleep(1);
+			tmo--;
+			goto retry;
+		}
+
+		/* we got some results, but there are more pending... */
+		if (rc == -ENOSPC && overflow_retry--) {
+			ars_status = acpi_desc->ars_status;
+			/*
+			 * Record the original scrub range, so that we
+			 * can recall all the ranges impacted by the
+			 * initial scrub.
+			 */
+			if (!init_scrub_length) {
+				init_scrub_length = ars_status->length;
+				init_scrub_address = ars_status->address;
+			}
+			rc = ars_continue(acpi_desc);
+			if (rc == 0) {
+				mutex_unlock(&acpi_desc->init_mutex);
+				goto retry;
+			}
+		}
+
+		if (rc < 0) {
+			/*
+			 * Initial scrub failed, we'll give it one more
+			 * try below...
+			 */
+			break;
+		}
+
+		/* We got some final results, record completed ranges */
+		ars_status = acpi_desc->ars_status;
+		if (init_scrub_length) {
+			ars_start = init_scrub_address;
+			ars_len = ars_start + init_scrub_length;
+		} else {
+			ars_start = ars_status->address;
+			ars_len = ars_status->length;
+		}
+		spa = nfit_spa->spa;
+
+		if (!init_ars_done) {
+			init_ars_done = true;
+			dev_dbg(dev, "init scrub %#llx + %#llx complete\n",
+					ars_start, ars_len);
+		}
+		if (ars_start <= spa->address && ars_start + ars_len
+				>= spa->address + spa->length)
+			acpi_nfit_register_region(acpi_desc, nfit_spa);
+	}
+
+	/*
+	 * For all the ranges not covered by an initial scrub we still
+	 * want to see if there are errors, but it's ok to discover them
+	 * asynchronously.
+	 */
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		/*
+		 * Flag all the ranges that still need scrubbing, but
+		 * register them now to make data available.
+		 */
+		if (nfit_spa->nd_region)
+			nfit_spa->ars_done = 1;
+		else
+			acpi_nfit_register_region(acpi_desc, nfit_spa);
 	}
+
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
+		acpi_nfit_async_scrub(acpi_desc, nfit_spa);
+	mutex_unlock(&acpi_desc->init_mutex);
+}
+
+static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
+{
+	struct nfit_spa *nfit_spa;
+	int rc;
+
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
+		if (nfit_spa_type(nfit_spa->spa) == NFIT_SPA_DCR) {
+			/* BLK regions don't need to wait for ars results */
+			rc = acpi_nfit_register_region(acpi_desc, nfit_spa);
+			if (rc)
+				return rc;
+		}
+
+	queue_work(nfit_wq, &acpi_desc->work);
 	return 0;
 }
 
@@ -2019,6 +2209,7 @@ void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
 	INIT_LIST_HEAD(&acpi_desc->dimms);
 	mutex_init(&acpi_desc->spa_map_mutex);
 	mutex_init(&acpi_desc->init_mutex);
+	INIT_WORK(&acpi_desc->work, acpi_nfit_scrub);
 }
 EXPORT_SYMBOL_GPL(acpi_nfit_desc_init);
 
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index e8388fee4cc6..c75576b2d50e 100644
--- a/drivers/acpi/nfit.h
+++ b/drivers/acpi/nfit.h
@@ -57,12 +57,16 @@ enum {
 	NFIT_ARS_START_BUSY = 6,
 	NFIT_ARS_CAP_NONE = 1,
 	NFIT_ARS_F_OVERFLOW = 1,
+	NFIT_ARS_TIMEOUT = 90,
 };
 
 struct nfit_spa {
 	struct acpi_nfit_system_address *spa;
 	struct list_head list;
-	int is_registered;
+	struct nd_region *nd_region;
+	unsigned int ars_done:1;
+	u32 clear_err_unit;
+	u32 max_ars;
 };
 
 struct nfit_dcr {
@@ -124,6 +128,8 @@ struct acpi_nfit_desc {
 	struct list_head idts;
 	struct nvdimm_bus *nvdimm_bus;
 	struct device *dev;
+	struct nd_cmd_ars_status *ars_status;
+	size_t ars_status_size;
 	struct work_struct work;
 	unsigned int cancel:1;
 	unsigned long dimm_dsm_force_en;