Merge tag 'libnvdimm-for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dan Williams:
 "This cycle was was not something I ever want to repeat as there were
  several late changes that have only now just settled.

  Half of the branch up to commit d2c997c0f145 ("fs, dax: use
  page->mapping to warn...") have been in -next for several releases.
  The of_pmem driver and the address range scrub rework were late
  arrivals, and the dax work was scaled back at the last moment.

  The of_pmem driver missed a previous merge window due to an oversight.
  A sense of obligation to rectify that miss is why it is included for
  4.17. It has acks from PowerPC folks. Stephen reported a build failure
  that only occurs when merging it with your latest tree, for now I have
  fixed that up by disabling modular builds of of_pmem. A test merge
  with your tree has received a build success report from the 0day robot
  over 156 configs.

  An initial version of the ARS rework was submitted before the merge
  window. It is self contained to libnvdimm, a net code reduction, and
  passing all unit tests.

  The filesystem-dax changes are based on the wait_var_event()
  functionality from tip/sched/core. However, late review feedback
  showed that those changes regressed truncate performance to a large
  degree. The branch was rewound to drop the truncate behavior change
  and now only includes preparation patches and cleanups (with full acks
  and reviews). The finalization of this dax-dma-vs-trnucate work will
  need to wait for 4.18.

  Summary:

   - A rework of the filesytem-dax implementation provides for detection
     of unmap operations (truncate / hole punch) colliding with
     in-progress device-DMA. A fix for these collisions remains a
     work-in-progress pending resolution of truncate latency and
     starvation regressions.

   - The of_pmem driver expands the users of libnvdimm outside of x86
     and ACPI to describe an implementation of persistent memory on
     PowerPC with Open Firmware / Device tree.

   - Address Range Scrub (ARS) handling is completely rewritten to
     account for the fact that ARS may run for 100s of seconds and there
     is no platform defined way to cancel it. ARS will now no longer
     block namespace initialization.

   - The NVDIMM Namespace Label implementation is updated to handle
     label areas as small as 1K, down from 128K.

   - Miscellaneous cleanups and updates to unit test infrastructure"

* tag 'libnvdimm-for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (39 commits)
  libnvdimm, of_pmem: workaround OF_NUMA=n build error
  nfit, address-range-scrub: add module option to skip initial ars
  nfit, address-range-scrub: rework and simplify ARS state machine
  nfit, address-range-scrub: determine one platform max_ars value
  powerpc/powernv: Create platform devs for nvdimm buses
  doc/devicetree: Persistent memory region bindings
  libnvdimm: Add device-tree based driver
  libnvdimm: Add of_node to region and bus descriptors
  libnvdimm, region: quiet region probe
  libnvdimm, namespace: use a safe lookup for dimm device name
  libnvdimm, dimm: fix dpa reservation vs uninitialized label area
  libnvdimm, testing: update the default smart ctrl_temperature
  libnvdimm, testing: Add emulation for smart injection commands
  nfit, address-range-scrub: introduce nfit_spa->ars_state
  libnvdimm: add an api to cast a 'struct nd_region' to its 'struct device'
  nfit, address-range-scrub: fix scrub in-progress reporting
  dax, dm: allow device-mapper to operate without dax support
  dax: introduce CONFIG_DAX_DRIVER
  fs, dax: use page->mapping to warn if truncate collides with a busy page
  ext2, dax: introduce ext2_dax_aops
  ...

3 files changed, 339 insertions, 367 deletions

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 22a112b4f4d8..e2235ed3e4be 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -36,16 +36,6 @@ 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 bool disable_vendor_specific;
 module_param(disable_vendor_specific, bool, S_IRUGO);
 MODULE_PARM_DESC(disable_vendor_specific,
@@ -60,6 +50,10 @@ module_param(default_dsm_family, int, S_IRUGO);
 MODULE_PARM_DESC(default_dsm_family,
 		"Try this DSM type first when identifying NVDIMM family");
 
+static bool no_init_ars;
+module_param(no_init_ars, bool, 0644);
+MODULE_PARM_DESC(no_init_ars, "Skip ARS run at nfit init time");
+
 LIST_HEAD(acpi_descs);
 DEFINE_MUTEX(acpi_desc_lock);
 
@@ -197,7 +191,7 @@ static int xlat_nvdimm_status(struct nvdimm *nvdimm, void *buf, unsigned int cmd
 		 * In the _LSI, _LSR, _LSW case the locked status is
 		 * communicated via the read/write commands
 		 */
-		if (nfit_mem->has_lsi)
+		if (nfit_mem->has_lsr)
 			break;
 
 		if (status >> 16 & ND_CONFIG_LOCKED)
@@ -477,14 +471,14 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
 		in_buf.buffer.length = call_pkg->nd_size_in;
 	}
 
-	dev_dbg(dev, "%s:%s cmd: %d: func: %d input length: %d\n",
-			__func__, dimm_name, cmd, func, in_buf.buffer.length);
+	dev_dbg(dev, "%s cmd: %d: func: %d input length: %d\n",
+		dimm_name, cmd, func, in_buf.buffer.length);
 	print_hex_dump_debug("nvdimm in  ", DUMP_PREFIX_OFFSET, 4, 4,
 			in_buf.buffer.pointer,
 			min_t(u32, 256, in_buf.buffer.length), true);
 
 	/* call the BIOS, prefer the named methods over _DSM if available */
-	if (nvdimm && cmd == ND_CMD_GET_CONFIG_SIZE && nfit_mem->has_lsi)
+	if (nvdimm && cmd == ND_CMD_GET_CONFIG_SIZE && nfit_mem->has_lsr)
 		out_obj = acpi_label_info(handle);
 	else if (nvdimm && cmd == ND_CMD_GET_CONFIG_DATA && nfit_mem->has_lsr) {
 		struct nd_cmd_get_config_data_hdr *p = buf;
@@ -507,8 +501,7 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
 	}
 
 	if (!out_obj) {
-		dev_dbg(dev, "%s:%s _DSM failed cmd: %s\n", __func__, dimm_name,
-				cmd_name);
+		dev_dbg(dev, "%s _DSM failed cmd: %s\n", dimm_name, cmd_name);
 		return -EINVAL;
 	}
 
@@ -529,13 +522,13 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
 	}
 
 	if (out_obj->package.type != ACPI_TYPE_BUFFER) {
-		dev_dbg(dev, "%s:%s unexpected output object type cmd: %s type: %d\n",
-				__func__, dimm_name, cmd_name, out_obj->type);
+		dev_dbg(dev, "%s unexpected output object type cmd: %s type: %d\n",
+				dimm_name, cmd_name, out_obj->type);
 		rc = -EINVAL;
 		goto out;
 	}
 
-	dev_dbg(dev, "%s:%s cmd: %s output length: %d\n", __func__, dimm_name,
+	dev_dbg(dev, "%s cmd: %s output length: %d\n", dimm_name,
 			cmd_name, out_obj->buffer.length);
 	print_hex_dump_debug(cmd_name, DUMP_PREFIX_OFFSET, 4, 4,
 			out_obj->buffer.pointer,
@@ -547,14 +540,14 @@ int acpi_nfit_ctl(struct nvdimm_bus_descriptor *nd_desc, struct nvdimm *nvdimm,
 				out_obj->buffer.length - offset);
 
 		if (offset + out_size > out_obj->buffer.length) {
-			dev_dbg(dev, "%s:%s output object underflow cmd: %s field: %d\n",
-					__func__, dimm_name, cmd_name, i);
+			dev_dbg(dev, "%s output object underflow cmd: %s field: %d\n",
+					dimm_name, cmd_name, i);
 			break;
 		}
 
 		if (in_buf.buffer.length + offset + out_size > buf_len) {
-			dev_dbg(dev, "%s:%s output overrun cmd: %s field: %d\n",
-					__func__, dimm_name, cmd_name, i);
+			dev_dbg(dev, "%s output overrun cmd: %s field: %d\n",
+					dimm_name, cmd_name, i);
 			rc = -ENXIO;
 			goto out;
 		}
@@ -656,7 +649,7 @@ static bool add_spa(struct acpi_nfit_desc *acpi_desc,
 	INIT_LIST_HEAD(&nfit_spa->list);
 	memcpy(nfit_spa->spa, spa, sizeof(*spa));
 	list_add_tail(&nfit_spa->list, &acpi_desc->spas);
-	dev_dbg(dev, "%s: spa index: %d type: %s\n", __func__,
+	dev_dbg(dev, "spa index: %d type: %s\n",
 			spa->range_index,
 			spa_type_name(nfit_spa_type(spa)));
 	return true;
@@ -685,8 +678,8 @@ static bool add_memdev(struct acpi_nfit_desc *acpi_desc,
 	INIT_LIST_HEAD(&nfit_memdev->list);
 	memcpy(nfit_memdev->memdev, memdev, sizeof(*memdev));
 	list_add_tail(&nfit_memdev->list, &acpi_desc->memdevs);
-	dev_dbg(dev, "%s: memdev handle: %#x spa: %d dcr: %d flags: %#x\n",
-			__func__, memdev->device_handle, memdev->range_index,
+	dev_dbg(dev, "memdev handle: %#x spa: %d dcr: %d flags: %#x\n",
+			memdev->device_handle, memdev->range_index,
 			memdev->region_index, memdev->flags);
 	return true;
 }
@@ -754,7 +747,7 @@ static bool add_dcr(struct acpi_nfit_desc *acpi_desc,
 	INIT_LIST_HEAD(&nfit_dcr->list);
 	memcpy(nfit_dcr->dcr, dcr, sizeof_dcr(dcr));
 	list_add_tail(&nfit_dcr->list, &acpi_desc->dcrs);
-	dev_dbg(dev, "%s: dcr index: %d windows: %d\n", __func__,
+	dev_dbg(dev, "dcr index: %d windows: %d\n",
 			dcr->region_index, dcr->windows);
 	return true;
 }
@@ -781,7 +774,7 @@ static bool add_bdw(struct acpi_nfit_desc *acpi_desc,
 	INIT_LIST_HEAD(&nfit_bdw->list);
 	memcpy(nfit_bdw->bdw, bdw, sizeof(*bdw));
 	list_add_tail(&nfit_bdw->list, &acpi_desc->bdws);
-	dev_dbg(dev, "%s: bdw dcr: %d windows: %d\n", __func__,
+	dev_dbg(dev, "bdw dcr: %d windows: %d\n",
 			bdw->region_index, bdw->windows);
 	return true;
 }
@@ -820,7 +813,7 @@ static bool add_idt(struct acpi_nfit_desc *acpi_desc,
 	INIT_LIST_HEAD(&nfit_idt->list);
 	memcpy(nfit_idt->idt, idt, sizeof_idt(idt));
 	list_add_tail(&nfit_idt->list, &acpi_desc->idts);
-	dev_dbg(dev, "%s: idt index: %d num_lines: %d\n", __func__,
+	dev_dbg(dev, "idt index: %d num_lines: %d\n",
 			idt->interleave_index, idt->line_count);
 	return true;
 }
@@ -860,7 +853,7 @@ static bool add_flush(struct acpi_nfit_desc *acpi_desc,
 	INIT_LIST_HEAD(&nfit_flush->list);
 	memcpy(nfit_flush->flush, flush, sizeof_flush(flush));
 	list_add_tail(&nfit_flush->list, &acpi_desc->flushes);
-	dev_dbg(dev, "%s: nfit_flush handle: %d hint_count: %d\n", __func__,
+	dev_dbg(dev, "nfit_flush handle: %d hint_count: %d\n",
 			flush->device_handle, flush->hint_count);
 	return true;
 }
@@ -873,7 +866,7 @@ static bool add_platform_cap(struct acpi_nfit_desc *acpi_desc,
 
 	mask = (1 << (pcap->highest_capability + 1)) - 1;
 	acpi_desc->platform_cap = pcap->capabilities & mask;
-	dev_dbg(dev, "%s: cap: %#x\n", __func__, acpi_desc->platform_cap);
+	dev_dbg(dev, "cap: %#x\n", acpi_desc->platform_cap);
 	return true;
 }
 
@@ -920,7 +913,7 @@ static void *add_table(struct acpi_nfit_desc *acpi_desc,
 			return err;
 		break;
 	case ACPI_NFIT_TYPE_SMBIOS:
-		dev_dbg(dev, "%s: smbios\n", __func__);
+		dev_dbg(dev, "smbios\n");
 		break;
 	case ACPI_NFIT_TYPE_CAPABILITIES:
 		if (!add_platform_cap(acpi_desc, table))
@@ -1277,8 +1270,11 @@ static ssize_t scrub_show(struct device *dev,
 	if (nd_desc) {
 		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
 
+		mutex_lock(&acpi_desc->init_mutex);
 		rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
-				(work_busy(&acpi_desc->work)) ? "+\n" : "\n");
+				work_busy(&acpi_desc->dwork.work)
+				&& !acpi_desc->cancel ? "+\n" : "\n");
+		mutex_unlock(&acpi_desc->init_mutex);
 	}
 	device_unlock(dev);
 	return rc;
@@ -1648,7 +1644,7 @@ void __acpi_nvdimm_notify(struct device *dev, u32 event)
 	struct nfit_mem *nfit_mem;
 	struct acpi_nfit_desc *acpi_desc;
 
-	dev_dbg(dev->parent, "%s: %s: event: %d\n", dev_name(dev), __func__,
+	dev_dbg(dev->parent, "%s: event: %d\n", dev_name(dev),
 			event);
 
 	if (event != NFIT_NOTIFY_DIMM_HEALTH) {
@@ -1681,12 +1677,23 @@ static void acpi_nvdimm_notify(acpi_handle handle, u32 event, void *data)
 	device_unlock(dev->parent);
 }
 
+static bool acpi_nvdimm_has_method(struct acpi_device *adev, char *method)
+{
+	acpi_handle handle;
+	acpi_status status;
+
+	status = acpi_get_handle(adev->handle, method, &handle);
+
+	if (ACPI_SUCCESS(status))
+		return true;
+	return false;
+}
+
 static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc,
 		struct nfit_mem *nfit_mem, u32 device_handle)
 {
 	struct acpi_device *adev, *adev_dimm;
 	struct device *dev = acpi_desc->dev;
-	union acpi_object *obj;
 	unsigned long dsm_mask;
 	const guid_t *guid;
 	int i;
@@ -1759,25 +1766,15 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc,
 					1ULL << i))
 			set_bit(i, &nfit_mem->dsm_mask);
 
-	obj = acpi_label_info(adev_dimm->handle);
-	if (obj) {
-		ACPI_FREE(obj);
-		nfit_mem->has_lsi = 1;
-		dev_dbg(dev, "%s: has _LSI\n", dev_name(&adev_dimm->dev));
-	}
-
-	obj = acpi_label_read(adev_dimm->handle, 0, 0);
-	if (obj) {
-		ACPI_FREE(obj);
-		nfit_mem->has_lsr = 1;
+	if (acpi_nvdimm_has_method(adev_dimm, "_LSI")
+			&& acpi_nvdimm_has_method(adev_dimm, "_LSR")) {
 		dev_dbg(dev, "%s: has _LSR\n", dev_name(&adev_dimm->dev));
+		nfit_mem->has_lsr = true;
 	}
 
-	obj = acpi_label_write(adev_dimm->handle, 0, 0, NULL);
-	if (obj) {
-		ACPI_FREE(obj);
-		nfit_mem->has_lsw = 1;
+	if (nfit_mem->has_lsr && acpi_nvdimm_has_method(adev_dimm, "_LSW")) {
 		dev_dbg(dev, "%s: has _LSW\n", dev_name(&adev_dimm->dev));
+		nfit_mem->has_lsw = true;
 	}
 
 	return 0;
@@ -1866,10 +1863,10 @@ static int acpi_nfit_register_dimms(struct acpi_nfit_desc *acpi_desc)
 			cmd_mask |= nfit_mem->dsm_mask & NVDIMM_STANDARD_CMDMASK;
 		}
 
-		if (nfit_mem->has_lsi)
+		if (nfit_mem->has_lsr) {
 			set_bit(ND_CMD_GET_CONFIG_SIZE, &cmd_mask);
-		if (nfit_mem->has_lsr)
 			set_bit(ND_CMD_GET_CONFIG_DATA, &cmd_mask);
+		}
 		if (nfit_mem->has_lsw)
 			set_bit(ND_CMD_SET_CONFIG_DATA, &cmd_mask);
 
@@ -2365,7 +2362,7 @@ static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus,
 	nvdimm = nd_blk_region_to_dimm(ndbr);
 	nfit_mem = nvdimm_provider_data(nvdimm);
 	if (!nfit_mem || !nfit_mem->dcr || !nfit_mem->bdw) {
-		dev_dbg(dev, "%s: missing%s%s%s\n", __func__,
+		dev_dbg(dev, "missing%s%s%s\n",
 				nfit_mem ? "" : " nfit_mem",
 				(nfit_mem && nfit_mem->dcr) ? "" : " dcr",
 				(nfit_mem && nfit_mem->bdw) ? "" : " bdw");
@@ -2384,7 +2381,7 @@ static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus,
 	mmio->addr.base = devm_nvdimm_memremap(dev, nfit_mem->spa_bdw->address,
                         nfit_mem->spa_bdw->length, nd_blk_memremap_flags(ndbr));
 	if (!mmio->addr.base) {
-		dev_dbg(dev, "%s: %s failed to map bdw\n", __func__,
+		dev_dbg(dev, "%s failed to map bdw\n",
 				nvdimm_name(nvdimm));
 		return -ENOMEM;
 	}
@@ -2395,8 +2392,8 @@ static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus,
 	rc = nfit_blk_init_interleave(mmio, nfit_mem->idt_bdw,
 			nfit_mem->memdev_bdw->interleave_ways);
 	if (rc) {
-		dev_dbg(dev, "%s: %s failed to init bdw interleave\n",
-				__func__, nvdimm_name(nvdimm));
+		dev_dbg(dev, "%s failed to init bdw interleave\n",
+				nvdimm_name(nvdimm));
 		return rc;
 	}
 
@@ -2407,7 +2404,7 @@ static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus,
 	mmio->addr.base = devm_nvdimm_ioremap(dev, nfit_mem->spa_dcr->address,
 			nfit_mem->spa_dcr->length);
 	if (!mmio->addr.base) {
-		dev_dbg(dev, "%s: %s failed to map dcr\n", __func__,
+		dev_dbg(dev, "%s failed to map dcr\n",
 				nvdimm_name(nvdimm));
 		return -ENOMEM;
 	}
@@ -2418,15 +2415,15 @@ static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus,
 	rc = nfit_blk_init_interleave(mmio, nfit_mem->idt_dcr,
 			nfit_mem->memdev_dcr->interleave_ways);
 	if (rc) {
-		dev_dbg(dev, "%s: %s failed to init dcr interleave\n",
-				__func__, nvdimm_name(nvdimm));
+		dev_dbg(dev, "%s failed to init dcr interleave\n",
+				nvdimm_name(nvdimm));
 		return rc;
 	}
 
 	rc = acpi_nfit_blk_get_flags(nd_desc, nvdimm, nfit_blk);
 	if (rc < 0) {
-		dev_dbg(dev, "%s: %s failed get DIMM flags\n",
-				__func__, nvdimm_name(nvdimm));
+		dev_dbg(dev, "%s failed get DIMM flags\n",
+				nvdimm_name(nvdimm));
 		return rc;
 	}
 
@@ -2476,7 +2473,8 @@ static int ars_start(struct acpi_nfit_desc *acpi_desc, struct nfit_spa *nfit_spa
 	memset(&ars_start, 0, sizeof(ars_start));
 	ars_start.address = spa->address;
 	ars_start.length = spa->length;
-	ars_start.flags = acpi_desc->ars_start_flags;
+	if (test_bit(ARS_SHORT, &nfit_spa->ars_state))
+		ars_start.flags = ND_ARS_RETURN_PREV_DATA;
 	if (nfit_spa_type(spa) == NFIT_SPA_PM)
 		ars_start.type = ND_ARS_PERSISTENT;
 	else if (nfit_spa_type(spa) == NFIT_SPA_VOLATILE)
@@ -2518,16 +2516,62 @@ static int ars_get_status(struct acpi_nfit_desc *acpi_desc)
 	int rc, cmd_rc;
 
 	rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_STATUS, ars_status,
-			acpi_desc->ars_status_size, &cmd_rc);
+			acpi_desc->max_ars, &cmd_rc);
 	if (rc < 0)
 		return rc;
 	return cmd_rc;
 }
 
-static int ars_status_process_records(struct acpi_nfit_desc *acpi_desc,
-		struct nd_cmd_ars_status *ars_status)
+static void ars_complete(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_spa *nfit_spa)
+{
+	struct nd_cmd_ars_status *ars_status = acpi_desc->ars_status;
+	struct acpi_nfit_system_address *spa = nfit_spa->spa;
+	struct nd_region *nd_region = nfit_spa->nd_region;
+	struct device *dev;
+
+	if ((ars_status->address >= spa->address && ars_status->address
+				< spa->address + spa->length)
+			|| (ars_status->address < spa->address)) {
+		/*
+		 * Assume that if a scrub starts at an offset from the
+		 * start of nfit_spa that we are in the continuation
+		 * case.
+		 *
+		 * Otherwise, if the scrub covers the spa range, mark
+		 * any pending request complete.
+		 */
+		if (ars_status->address + ars_status->length
+				>= spa->address + spa->length)
+				/* complete */;
+		else
+			return;
+	} else
+		return;
+
+	if (test_bit(ARS_DONE, &nfit_spa->ars_state))
+		return;
+
+	if (!test_and_clear_bit(ARS_REQ, &nfit_spa->ars_state))
+		return;
+
+	if (nd_region) {
+		dev = nd_region_dev(nd_region);
+		nvdimm_region_notify(nd_region, NVDIMM_REVALIDATE_POISON);
+	} else
+		dev = acpi_desc->dev;
+
+	dev_dbg(dev, "ARS: range %d %s complete\n", spa->range_index,
+			test_bit(ARS_SHORT, &nfit_spa->ars_state)
+			? "short" : "long");
+	clear_bit(ARS_SHORT, &nfit_spa->ars_state);
+	set_bit(ARS_DONE, &nfit_spa->ars_state);
+}
+
+static int ars_status_process_records(struct acpi_nfit_desc *acpi_desc)
 {
 	struct nvdimm_bus *nvdimm_bus = acpi_desc->nvdimm_bus;
+	struct nd_cmd_ars_status *ars_status = acpi_desc->ars_status;
 	int rc;
 	u32 i;
 
@@ -2606,7 +2650,7 @@ static int acpi_nfit_init_mapping(struct acpi_nfit_desc *acpi_desc,
 	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, rc;
+	int rc;
 
 	if (!nvdimm) {
 		dev_err(acpi_desc->dev, "spa%d dimm: %#x not found\n",
@@ -2626,15 +2670,14 @@ static int acpi_nfit_init_mapping(struct acpi_nfit_desc *acpi_desc,
 		if (!nfit_mem || !nfit_mem->bdw) {
 			dev_dbg(acpi_desc->dev, "spa%d %s missing bdw\n",
 					spa->range_index, nvdimm_name(nvdimm));
-		} else {
-			mapping->size = nfit_mem->bdw->capacity;
-			mapping->start = nfit_mem->bdw->start_address;
-			ndr_desc->num_lanes = nfit_mem->bdw->windows;
-			blk_valid = 1;
+			break;
 		}
 
+		mapping->size = nfit_mem->bdw->capacity;
+		mapping->start = nfit_mem->bdw->start_address;
+		ndr_desc->num_lanes = nfit_mem->bdw->windows;
 		ndr_desc->mapping = mapping;
-		ndr_desc->num_mappings = blk_valid;
+		ndr_desc->num_mappings = 1;
 		ndbr_desc = to_blk_region_desc(ndr_desc);
 		ndbr_desc->enable = acpi_nfit_blk_region_enable;
 		ndbr_desc->do_io = acpi_desc->blk_do_io;
@@ -2682,8 +2725,7 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
 		return 0;
 
 	if (spa->range_index == 0 && !nfit_spa_is_virtual(spa)) {
-		dev_dbg(acpi_desc->dev, "%s: detected invalid spa index\n",
-				__func__);
+		dev_dbg(acpi_desc->dev, "detected invalid spa index\n");
 		return 0;
 	}
 
@@ -2769,301 +2811,243 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
 	return rc;
 }
 
-static int ars_status_alloc(struct acpi_nfit_desc *acpi_desc,
-		u32 max_ars)
+static int ars_status_alloc(struct acpi_nfit_desc *acpi_desc)
 {
 	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);
+	if (acpi_desc->ars_status) {
+		memset(acpi_desc->ars_status, 0, acpi_desc->max_ars);
 		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);
+	ars_status = devm_kzalloc(dev, acpi_desc->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_query_poison(struct acpi_nfit_desc *acpi_desc,
-		struct nfit_spa *nfit_spa)
+static int acpi_nfit_query_poison(struct acpi_nfit_desc *acpi_desc)
 {
-	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))
+	if (ars_status_alloc(acpi_desc))
 		return -ENOMEM;
 
 	rc = ars_get_status(acpi_desc);
+
 	if (rc < 0 && rc != -ENOSPC)
 		return rc;
 
-	if (ars_status_process_records(acpi_desc, acpi_desc->ars_status))
+	if (ars_status_process_records(acpi_desc))
 		return -ENOMEM;
 
 	return 0;
 }
 
-static void acpi_nfit_async_scrub(struct acpi_nfit_desc *acpi_desc,
-		struct nfit_spa *nfit_spa)
+static int ars_register(struct acpi_nfit_desc *acpi_desc, struct nfit_spa *nfit_spa,
+		int *query_rc)
 {
-	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;
+	int rc = *query_rc;
 
-	if (!nfit_spa->ars_required || !nfit_spa->nd_region)
-		return;
+	if (no_init_ars)
+		return acpi_nfit_register_region(acpi_desc, nfit_spa);
 
-	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;
-		}
+	set_bit(ARS_REQ, &nfit_spa->ars_state);
+	set_bit(ARS_SHORT, &nfit_spa->ars_state);
 
+	switch (rc) {
+	case 0:
+	case -EAGAIN:
+		rc = ars_start(acpi_desc, nfit_spa);
 		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);
+			*query_rc = rc;
 			break;
-		}
-
-		if (init_ars_len) {
-			ars_start = init_ars_start;
-			ars_len = init_ars_len;
+		} else if (rc == 0) {
+			rc = acpi_nfit_query_poison(acpi_desc);
 		} else {
-			ars_start = acpi_desc->ars_status->address;
-			ars_len = acpi_desc->ars_status->length;
+			set_bit(ARS_FAILED, &nfit_spa->ars_state);
+			break;
 		}
-		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);
+		if (rc == -EAGAIN)
+			clear_bit(ARS_SHORT, &nfit_spa->ars_state);
+		else if (rc == 0)
+			ars_complete(acpi_desc, nfit_spa);
 		break;
-	} while (1);
+	case -EBUSY:
+	case -ENOSPC:
+		break;
+	default:
+		set_bit(ARS_FAILED, &nfit_spa->ars_state);
+		break;
+	}
+
+	if (test_and_clear_bit(ARS_DONE, &nfit_spa->ars_state))
+		set_bit(ARS_REQ, &nfit_spa->ars_state);
+
+	return acpi_nfit_register_region(acpi_desc, nfit_spa);
 }
 
-static void acpi_nfit_scrub(struct work_struct *work)
+static void ars_complete_all(struct acpi_nfit_desc *acpi_desc)
 {
-	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. 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.
-	 */
 
-	/* process platform firmware initiated scrubs */
- retry:
-	mutex_lock(&acpi_desc->init_mutex);
 	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
-		struct nd_cmd_ars_status *ars_status;
-		struct acpi_nfit_system_address *spa;
-		u64 ars_start, ars_len;
-		int rc;
-
-		if (acpi_desc->cancel)
-			break;
-
-		if (nfit_spa->nd_region)
+		if (test_bit(ARS_FAILED, &nfit_spa->ars_state))
 			continue;
+		ars_complete(acpi_desc, nfit_spa);
+	}
+}
 
-		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;
-			}
-		}
+static unsigned int __acpi_nfit_scrub(struct acpi_nfit_desc *acpi_desc,
+		int query_rc)
+{
+	unsigned int tmo = acpi_desc->scrub_tmo;
+	struct device *dev = acpi_desc->dev;
+	struct nfit_spa *nfit_spa;
 
-		if (rc < 0) {
-			/*
-			 * Initial scrub failed, we'll give it one more
-			 * try below...
-			 */
-			break;
-		}
+	if (acpi_desc->cancel)
+		return 0;
 
-		/* 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 (query_rc == -EBUSY) {
+		dev_dbg(dev, "ARS: ARS busy\n");
+		return min(30U * 60U, tmo * 2);
+	}
+	if (query_rc == -ENOSPC) {
+		dev_dbg(dev, "ARS: ARS continue\n");
+		ars_continue(acpi_desc);
+		return 1;
+	}
+	if (query_rc && query_rc != -EAGAIN) {
+		unsigned long long addr, end;
 
-		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);
+		addr = acpi_desc->ars_status->address;
+		end = addr + acpi_desc->ars_status->length;
+		dev_dbg(dev, "ARS: %llx-%llx failed (%d)\n", addr, end,
+				query_rc);
 	}
 
-	/*
-	 * 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.
-	 */
+	ars_complete_all(acpi_desc);
 	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_required = 1;
-			acpi_nfit_register_region(acpi_desc, nfit_spa);
+		if (test_bit(ARS_FAILED, &nfit_spa->ars_state))
+			continue;
+		if (test_bit(ARS_REQ, &nfit_spa->ars_state)) {
+			int rc = ars_start(acpi_desc, nfit_spa);
+
+			clear_bit(ARS_DONE, &nfit_spa->ars_state);
+			dev = nd_region_dev(nfit_spa->nd_region);
+			dev_dbg(dev, "ARS: range %d ARS start (%d)\n",
+					nfit_spa->spa->range_index, rc);
+			if (rc == 0 || rc == -EBUSY)
+				return 1;
+			dev_err(dev, "ARS: range %d ARS failed (%d)\n",
+					nfit_spa->spa->range_index, rc);
+			set_bit(ARS_FAILED, &nfit_spa->ars_state);
 		}
 	}
-	acpi_desc->init_complete = 1;
+	return 0;
+}
 
-	list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
-		acpi_nfit_async_scrub(acpi_desc, nfit_spa);
-	acpi_desc->scrub_count++;
-	acpi_desc->ars_start_flags = 0;
-	if (acpi_desc->scrub_count_state)
-		sysfs_notify_dirent(acpi_desc->scrub_count_state);
+static void acpi_nfit_scrub(struct work_struct *work)
+{
+	struct acpi_nfit_desc *acpi_desc;
+	unsigned int tmo;
+	int query_rc;
+
+	acpi_desc = container_of(work, typeof(*acpi_desc), dwork.work);
+	mutex_lock(&acpi_desc->init_mutex);
+	query_rc = acpi_nfit_query_poison(acpi_desc);
+	tmo = __acpi_nfit_scrub(acpi_desc, query_rc);
+	if (tmo) {
+		queue_delayed_work(nfit_wq, &acpi_desc->dwork, tmo * HZ);
+		acpi_desc->scrub_tmo = tmo;
+	} else {
+		acpi_desc->scrub_count++;
+		if (acpi_desc->scrub_count_state)
+			sysfs_notify_dirent(acpi_desc->scrub_count_state);
+	}
+	memset(acpi_desc->ars_status, 0, acpi_desc->max_ars);
 	mutex_unlock(&acpi_desc->init_mutex);
 }
 
+static void acpi_nfit_init_ars(struct acpi_nfit_desc *acpi_desc,
+		struct nfit_spa *nfit_spa)
+{
+	int type = nfit_spa_type(nfit_spa->spa);
+	struct nd_cmd_ars_cap ars_cap;
+	int rc;
+
+	memset(&ars_cap, 0, sizeof(ars_cap));
+	rc = ars_get_cap(acpi_desc, &ars_cap, nfit_spa);
+	if (rc < 0)
+		return;
+	/* check that the supported scrub types match the spa type */
+	if (type == NFIT_SPA_VOLATILE && ((ars_cap.status >> 16)
+				& ND_ARS_VOLATILE) == 0)
+		return;
+	if (type == NFIT_SPA_PM && ((ars_cap.status >> 16)
+				& ND_ARS_PERSISTENT) == 0)
+		return;
+
+	nfit_spa->max_ars = ars_cap.max_ars_out;
+	nfit_spa->clear_err_unit = ars_cap.clear_err_unit;
+	acpi_desc->max_ars = max(nfit_spa->max_ars, acpi_desc->max_ars);
+	clear_bit(ARS_FAILED, &nfit_spa->ars_state);
+	set_bit(ARS_REQ, &nfit_spa->ars_state);
+}
+
 static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc)
 {
 	struct nfit_spa *nfit_spa;
-	int rc;
+	int rc, query_rc;
+
+	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
+		set_bit(ARS_FAILED, &nfit_spa->ars_state);
+		switch (nfit_spa_type(nfit_spa->spa)) {
+		case NFIT_SPA_VOLATILE:
+		case NFIT_SPA_PM:
+			acpi_nfit_init_ars(acpi_desc, nfit_spa);
+			break;
+		}
+	}
+
+	/*
+	 * Reap any results that might be pending before starting new
+	 * short requests.
+	 */
+	query_rc = acpi_nfit_query_poison(acpi_desc);
+	if (query_rc == 0)
+		ars_complete_all(acpi_desc);
 
 	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 */
+		switch (nfit_spa_type(nfit_spa->spa)) {
+		case NFIT_SPA_VOLATILE:
+		case NFIT_SPA_PM:
+			/* register regions and kick off initial ARS run */
+			rc = ars_register(acpi_desc, nfit_spa, &query_rc);
+			if (rc)
+				return rc;
+			break;
+		case NFIT_SPA_BDW:
+			/* nothing to register */
+			break;
+		case NFIT_SPA_DCR:
+		case NFIT_SPA_VDISK:
+		case NFIT_SPA_VCD:
+		case NFIT_SPA_PDISK:
+		case NFIT_SPA_PCD:
+			/* register known regions that don't support ARS */
 			rc = acpi_nfit_register_region(acpi_desc, nfit_spa);
 			if (rc)
 				return rc;
+			break;
+		default:
+			/* don't register unknown regions */
+			break;
 		}
 
-	acpi_desc->ars_start_flags = 0;
-	if (!acpi_desc->cancel)
-		queue_work(nfit_wq, &acpi_desc->work);
+	queue_delayed_work(nfit_wq, &acpi_desc->dwork, 0);
 	return 0;
 }
 
@@ -3173,8 +3157,7 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 		data = add_table(acpi_desc, &prev, data, end);
 
 	if (IS_ERR(data)) {
-		dev_dbg(dev, "%s: nfit table parsing error: %ld\n", __func__,
-				PTR_ERR(data));
+		dev_dbg(dev, "nfit table parsing error: %ld\n",	PTR_ERR(data));
 		rc = PTR_ERR(data);
 		goto out_unlock;
 	}
@@ -3199,49 +3182,20 @@ int acpi_nfit_init(struct acpi_nfit_desc *acpi_desc, void *data, acpi_size sz)
 }
 EXPORT_SYMBOL_GPL(acpi_nfit_init);
 
-struct acpi_nfit_flush_work {
-	struct work_struct work;
-	struct completion cmp;
-};
-
-static void flush_probe(struct work_struct *work)
-{
-	struct acpi_nfit_flush_work *flush;
-
-	flush = container_of(work, typeof(*flush), work);
-	complete(&flush->cmp);
-}
-
 static int acpi_nfit_flush_probe(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 acpi_nfit_flush_work flush;
-	int rc;
 
-	/* bounce the device lock to flush acpi_nfit_add / acpi_nfit_notify */
+	/* Bounce the device lock to flush acpi_nfit_add / acpi_nfit_notify */
 	device_lock(dev);
 	device_unlock(dev);
 
-	/* bounce the init_mutex to make init_complete valid */
+	/* Bounce the init_mutex to complete initial registration */
 	mutex_lock(&acpi_desc->init_mutex);
-	if (acpi_desc->cancel || acpi_desc->init_complete) {
-		mutex_unlock(&acpi_desc->init_mutex);
-		return 0;
-	}
-
-	/*
-	 * Scrub work could take 10s of seconds, userspace may give up so we
-	 * need to be interruptible while waiting.
-	 */
-	INIT_WORK_ONSTACK(&flush.work, flush_probe);
-	init_completion(&flush.cmp);
-	queue_work(nfit_wq, &flush.work);
 	mutex_unlock(&acpi_desc->init_mutex);
 
-	rc = wait_for_completion_interruptible(&flush.cmp);
-	cancel_work_sync(&flush.work);
-	return rc;
+	return 0;
 }
 
 static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
@@ -3260,20 +3214,18 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
 	 * just needs guarantees that any ars it initiates are not
 	 * interrupted by any intervening start reqeusts from userspace.
 	 */
-	if (work_busy(&acpi_desc->work))
+	if (work_busy(&acpi_desc->dwork.work))
 		return -EBUSY;
 
 	return 0;
 }
 
-int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc, u8 flags)
+int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc, unsigned long flags)
 {
 	struct device *dev = acpi_desc->dev;
+	int scheduled = 0, busy = 0;
 	struct nfit_spa *nfit_spa;
 
-	if (work_busy(&acpi_desc->work))
-		return -EBUSY;
-
 	mutex_lock(&acpi_desc->init_mutex);
 	if (acpi_desc->cancel) {
 		mutex_unlock(&acpi_desc->init_mutex);
@@ -3281,19 +3233,32 @@ int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc, u8 flags)
 	}
 
 	list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
-		struct acpi_nfit_system_address *spa = nfit_spa->spa;
+		int type = nfit_spa_type(nfit_spa->spa);
 
-		if (nfit_spa_type(spa) != NFIT_SPA_PM)
+		if (type != NFIT_SPA_PM && type != NFIT_SPA_VOLATILE)
+			continue;
+		if (test_bit(ARS_FAILED, &nfit_spa->ars_state))
 			continue;
 
-		nfit_spa->ars_required = 1;
+		if (test_and_set_bit(ARS_REQ, &nfit_spa->ars_state))
+			busy++;
+		else {
+			if (test_bit(ARS_SHORT, &flags))
+				set_bit(ARS_SHORT, &nfit_spa->ars_state);
+			scheduled++;
+		}
+	}
+	if (scheduled) {
+		queue_delayed_work(nfit_wq, &acpi_desc->dwork, 0);
+		dev_dbg(dev, "ars_scan triggered\n");
 	}
-	acpi_desc->ars_start_flags = flags;
-	queue_work(nfit_wq, &acpi_desc->work);
-	dev_dbg(dev, "%s: ars_scan triggered\n", __func__);
 	mutex_unlock(&acpi_desc->init_mutex);
 
-	return 0;
+	if (scheduled)
+		return 0;
+	if (busy)
+		return -EBUSY;
+	return -ENOTTY;
 }
 
 void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
@@ -3320,7 +3285,8 @@ void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
 	INIT_LIST_HEAD(&acpi_desc->dimms);
 	INIT_LIST_HEAD(&acpi_desc->list);
 	mutex_init(&acpi_desc->init_mutex);
-	INIT_WORK(&acpi_desc->work, acpi_nfit_scrub);
+	acpi_desc->scrub_tmo = 1;
+	INIT_DELAYED_WORK(&acpi_desc->dwork, acpi_nfit_scrub);
 }
 EXPORT_SYMBOL_GPL(acpi_nfit_desc_init);
 
@@ -3344,6 +3310,7 @@ void acpi_nfit_shutdown(void *data)
 
 	mutex_lock(&acpi_desc->init_mutex);
 	acpi_desc->cancel = 1;
+	cancel_delayed_work_sync(&acpi_desc->dwork);
 	mutex_unlock(&acpi_desc->init_mutex);
 
 	/*
@@ -3397,8 +3364,8 @@ static int acpi_nfit_add(struct acpi_device *adev)
 			rc = acpi_nfit_init(acpi_desc, obj->buffer.pointer,
 					obj->buffer.length);
 		else
-			dev_dbg(dev, "%s invalid type %d, ignoring _FIT\n",
-				 __func__, (int) obj->type);
+			dev_dbg(dev, "invalid type %d, ignoring _FIT\n",
+				(int) obj->type);
 		kfree(buf.pointer);
 	} else
 		/* skip over the lead-in header table */
@@ -3427,7 +3394,7 @@ static void acpi_nfit_update_notify(struct device *dev, acpi_handle handle)
 
 	if (!dev->driver) {
 		/* dev->driver may be null if we're being removed */
-		dev_dbg(dev, "%s: no driver found for dev\n", __func__);
+		dev_dbg(dev, "no driver found for dev\n");
 		return;
 	}
 
@@ -3465,15 +3432,15 @@ static void acpi_nfit_update_notify(struct device *dev, acpi_handle handle)
 static void acpi_nfit_uc_error_notify(struct device *dev, acpi_handle handle)
 {
 	struct acpi_nfit_desc *acpi_desc = dev_get_drvdata(dev);
-	u8 flags = (acpi_desc->scrub_mode == HW_ERROR_SCRUB_ON) ?
-			0 : ND_ARS_RETURN_PREV_DATA;
+	unsigned long flags = (acpi_desc->scrub_mode == HW_ERROR_SCRUB_ON) ?
+			0 : 1 << ARS_SHORT;
 
 	acpi_nfit_ars_rescan(acpi_desc, flags);
 }
 
 void __acpi_nfit_notify(struct device *dev, acpi_handle handle, u32 event)
 {
-	dev_dbg(dev, "%s: event: 0x%x\n", __func__, event);
+	dev_dbg(dev, "event: 0x%x\n", event);
 
 	switch (event) {
 	case NFIT_NOTIFY_UPDATE:
diff --git a/drivers/acpi/nfit/mce.c b/drivers/acpi/nfit/mce.c
index b92921439657..e9626bf6ca29 100644
--- a/drivers/acpi/nfit/mce.c
+++ b/drivers/acpi/nfit/mce.c
@@ -51,9 +51,8 @@ static int nfit_handle_mce(struct notifier_block *nb, unsigned long val,
 			if ((spa->address + spa->length - 1) < mce->addr)
 				continue;
 			found_match = 1;
-			dev_dbg(dev, "%s: addr in SPA %d (0x%llx, 0x%llx)\n",
-				__func__, spa->range_index, spa->address,
-				spa->length);
+			dev_dbg(dev, "addr in SPA %d (0x%llx, 0x%llx)\n",
+				spa->range_index, spa->address, spa->length);
 			/*
 			 * We can break at the first match because we're going
 			 * to rescan all the SPA ranges. There shouldn't be any
diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h
index 50d36e166d70..7d15856a739f 100644
--- a/drivers/acpi/nfit/nfit.h
+++ b/drivers/acpi/nfit/nfit.h
@@ -117,10 +117,17 @@ enum nfit_dimm_notifiers {
 	NFIT_NOTIFY_DIMM_HEALTH = 0x81,
 };
 
+enum nfit_ars_state {
+	ARS_REQ,
+	ARS_DONE,
+	ARS_SHORT,
+	ARS_FAILED,
+};
+
 struct nfit_spa {
 	struct list_head list;
 	struct nd_region *nd_region;
-	unsigned int ars_required:1;
+	unsigned long ars_state;
 	u32 clear_err_unit;
 	u32 max_ars;
 	struct acpi_nfit_system_address spa[0];
@@ -171,9 +178,8 @@ struct nfit_mem {
 	struct resource *flush_wpq;
 	unsigned long dsm_mask;
 	int family;
-	u32 has_lsi:1;
-	u32 has_lsr:1;
-	u32 has_lsw:1;
+	bool has_lsr;
+	bool has_lsw;
 };
 
 struct acpi_nfit_desc {
@@ -191,18 +197,18 @@ struct acpi_nfit_desc {
 	struct device *dev;
 	u8 ars_start_flags;
 	struct nd_cmd_ars_status *ars_status;
-	size_t ars_status_size;
-	struct work_struct work;
+	struct delayed_work dwork;
 	struct list_head list;
 	struct kernfs_node *scrub_count_state;
+	unsigned int max_ars;
 	unsigned int scrub_count;
 	unsigned int scrub_mode;
 	unsigned int cancel:1;
-	unsigned int init_complete:1;
 	unsigned long dimm_cmd_force_en;
 	unsigned long bus_cmd_force_en;
 	unsigned long bus_nfit_cmd_force_en;
 	unsigned int platform_cap;
+	unsigned int scrub_tmo;
 	int (*blk_do_io)(struct nd_blk_region *ndbr, resource_size_t dpa,
 			void *iobuf, u64 len, int rw);
 };
@@ -244,7 +250,7 @@ struct nfit_blk {
 
 extern struct list_head acpi_descs;
 extern struct mutex acpi_desc_lock;
-int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc, u8 flags);
+int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc, unsigned long flags);
 
 #ifdef CONFIG_X86_MCE
 void nfit_mce_register(void);