diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
index 14d9f5b..5912d30 100644
--- a/drivers/acpi/nfit/core.c
+++ b/drivers/acpi/nfit/core.c
@@ -1308,7 +1308,7 @@ static ssize_t scrub_store(struct device *dev,
 	if (nd_desc) {
 		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
 
-		rc = acpi_nfit_ars_rescan(acpi_desc, 0);
+		rc = acpi_nfit_ars_rescan(acpi_desc, ARS_REQ_LONG);
 	}
 	device_unlock(dev);
 	if (rc)
diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index 182258f..d0c621b 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -111,6 +111,8 @@ resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
 		struct nd_mapping *nd_mapping, resource_size_t *overlap);
 resource_size_t nd_blk_available_dpa(struct nd_region *nd_region);
 resource_size_t nd_region_available_dpa(struct nd_region *nd_region);
+int nd_region_conflict(struct nd_region *nd_region, resource_size_t start,
+		resource_size_t size);
 resource_size_t nvdimm_allocated_dpa(struct nvdimm_drvdata *ndd,
 		struct nd_label_id *label_id);
 int alias_dpa_busy(struct device *dev, void *data);
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 24c6409..6f22272 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -649,14 +649,47 @@ static u64 phys_pmem_align_down(struct nd_pfn *nd_pfn, u64 phys)
 			ALIGN_DOWN(phys, nd_pfn->align));
 }
 
+/*
+ * Check if pmem collides with 'System RAM', or other regions when
+ * section aligned.  Trim it accordingly.
+ */
+static void trim_pfn_device(struct nd_pfn *nd_pfn, u32 *start_pad, u32 *end_trunc)
+{
+	struct nd_namespace_common *ndns = nd_pfn->ndns;
+	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
+	struct nd_region *nd_region = to_nd_region(nd_pfn->dev.parent);
+	const resource_size_t start = nsio->res.start;
+	const resource_size_t end = start + resource_size(&nsio->res);
+	resource_size_t adjust, size;
+
+	*start_pad = 0;
+	*end_trunc = 0;
+
+	adjust = start - PHYS_SECTION_ALIGN_DOWN(start);
+	size = resource_size(&nsio->res) + adjust;
+	if (region_intersects(start - adjust, size, IORESOURCE_SYSTEM_RAM,
+				IORES_DESC_NONE) == REGION_MIXED
+			|| nd_region_conflict(nd_region, start - adjust, size))
+		*start_pad = PHYS_SECTION_ALIGN_UP(start) - start;
+
+	/* Now check that end of the range does not collide. */
+	adjust = PHYS_SECTION_ALIGN_UP(end) - end;
+	size = resource_size(&nsio->res) + adjust;
+	if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
+				IORES_DESC_NONE) == REGION_MIXED
+			|| !IS_ALIGNED(end, nd_pfn->align)
+			|| nd_region_conflict(nd_region, start, size + adjust))
+		*end_trunc = end - phys_pmem_align_down(nd_pfn, end);
+}
+
 static int nd_pfn_init(struct nd_pfn *nd_pfn)
 {
 	u32 dax_label_reserve = is_nd_dax(&nd_pfn->dev) ? SZ_128K : 0;
 	struct nd_namespace_common *ndns = nd_pfn->ndns;
-	u32 start_pad = 0, end_trunc = 0;
+	struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
 	resource_size_t start, size;
-	struct nd_namespace_io *nsio;
 	struct nd_region *nd_region;
+	u32 start_pad, end_trunc;
 	struct nd_pfn_sb *pfn_sb;
 	unsigned long npfns;
 	phys_addr_t offset;
@@ -688,30 +721,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
 
 	memset(pfn_sb, 0, sizeof(*pfn_sb));
 
-	/*
-	 * Check if pmem collides with 'System RAM' when section aligned and
-	 * trim it accordingly
-	 */
-	nsio = to_nd_namespace_io(&ndns->dev);
-	start = PHYS_SECTION_ALIGN_DOWN(nsio->res.start);
-	size = resource_size(&nsio->res);
-	if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
-				IORES_DESC_NONE) == REGION_MIXED) {
-		start = nsio->res.start;
-		start_pad = PHYS_SECTION_ALIGN_UP(start) - start;
-	}
-
-	start = nsio->res.start;
-	size = PHYS_SECTION_ALIGN_UP(start + size) - start;
-	if (region_intersects(start, size, IORESOURCE_SYSTEM_RAM,
-				IORES_DESC_NONE) == REGION_MIXED
-			|| !IS_ALIGNED(start + resource_size(&nsio->res),
-				nd_pfn->align)) {
-		size = resource_size(&nsio->res);
-		end_trunc = start + size - phys_pmem_align_down(nd_pfn,
-				start + size);
-	}
-
+	trim_pfn_device(nd_pfn, &start_pad, &end_trunc);
 	if (start_pad + end_trunc)
 		dev_info(&nd_pfn->dev, "%s alignment collision, truncate %d bytes\n",
 				dev_name(&ndns->dev), start_pad + end_trunc);
@@ -722,7 +732,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
 	 * implementation will limit the pfns advertised through
 	 * ->direct_access() to those that are included in the memmap.
 	 */
-	start += start_pad;
+	start = nsio->res.start + start_pad;
 	size = resource_size(&nsio->res);
 	npfns = PFN_SECTION_ALIGN_UP((size - start_pad - end_trunc - SZ_8K)
 			/ PAGE_SIZE);
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 174a418..e7377f1 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -1184,6 +1184,47 @@ int nvdimm_has_cache(struct nd_region *nd_region)
 }
 EXPORT_SYMBOL_GPL(nvdimm_has_cache);
 
+struct conflict_context {
+	struct nd_region *nd_region;
+	resource_size_t start, size;
+};
+
+static int region_conflict(struct device *dev, void *data)
+{
+	struct nd_region *nd_region;
+	struct conflict_context *ctx = data;
+	resource_size_t res_end, region_end, region_start;
+
+	if (!is_memory(dev))
+		return 0;
+
+	nd_region = to_nd_region(dev);
+	if (nd_region == ctx->nd_region)
+		return 0;
+
+	res_end = ctx->start + ctx->size;
+	region_start = nd_region->ndr_start;
+	region_end = region_start + nd_region->ndr_size;
+	if (ctx->start >= region_start && ctx->start < region_end)
+		return -EBUSY;
+	if (res_end > region_start && res_end <= region_end)
+		return -EBUSY;
+	return 0;
+}
+
+int nd_region_conflict(struct nd_region *nd_region, resource_size_t start,
+		resource_size_t size)
+{
+	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&nd_region->dev);
+	struct conflict_context ctx = {
+		.nd_region = nd_region,
+		.start = start,
+		.size = size,
+	};
+
+	return device_for_each_child(&nvdimm_bus->dev, &ctx, region_conflict);
+}
+
 void __exit nd_region_devs_exit(void)
 {
 	ida_destroy(&region_ida);
diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c
index 01ec04b..6c16ac3 100644
--- a/tools/testing/nvdimm/test/nfit.c
+++ b/tools/testing/nvdimm/test/nfit.c
@@ -15,6 +15,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/workqueue.h>
 #include <linux/libnvdimm.h>
+#include <linux/genalloc.h>
 #include <linux/vmalloc.h>
 #include <linux/device.h>
 #include <linux/module.h>
@@ -215,6 +216,8 @@ struct nfit_test {
 
 static struct workqueue_struct *nfit_wq;
 
+static struct gen_pool *nfit_pool;
+
 static struct nfit_test *to_nfit_test(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
@@ -1132,6 +1135,9 @@ static void release_nfit_res(void *data)
 	list_del(&nfit_res->list);
 	spin_unlock(&nfit_test_lock);
 
+	if (resource_size(&nfit_res->res) >= DIMM_SIZE)
+		gen_pool_free(nfit_pool, nfit_res->res.start,
+				resource_size(&nfit_res->res));
 	vfree(nfit_res->buf);
 	kfree(nfit_res);
 }
@@ -1144,7 +1150,7 @@ static void *__test_alloc(struct nfit_test *t, size_t size, dma_addr_t *dma,
 			GFP_KERNEL);
 	int rc;
 
-	if (!buf || !nfit_res)
+	if (!buf || !nfit_res || !*dma)
 		goto err;
 	rc = devm_add_action(dev, release_nfit_res, nfit_res);
 	if (rc)
@@ -1164,6 +1170,8 @@ static void *__test_alloc(struct nfit_test *t, size_t size, dma_addr_t *dma,
 
 	return nfit_res->buf;
  err:
+	if (*dma && size >= DIMM_SIZE)
+		gen_pool_free(nfit_pool, *dma, size);
 	if (buf)
 		vfree(buf);
 	kfree(nfit_res);
@@ -1172,9 +1180,16 @@ static void *__test_alloc(struct nfit_test *t, size_t size, dma_addr_t *dma,
 
 static void *test_alloc(struct nfit_test *t, size_t size, dma_addr_t *dma)
 {
+	struct genpool_data_align data = {
+		.align = SZ_128M,
+	};
 	void *buf = vmalloc(size);
 
-	*dma = (unsigned long) buf;
+	if (size >= DIMM_SIZE)
+		*dma = gen_pool_alloc_algo(nfit_pool, size,
+				gen_pool_first_fit_align, &data);
+	else
+		*dma = (unsigned long) buf;
 	return __test_alloc(t, size, dma, buf);
 }
 
@@ -2839,6 +2854,17 @@ static __init int nfit_test_init(void)
 		goto err_register;
 	}
 
+	nfit_pool = gen_pool_create(ilog2(SZ_4M), NUMA_NO_NODE);
+	if (!nfit_pool) {
+		rc = -ENOMEM;
+		goto err_register;
+	}
+
+	if (gen_pool_add(nfit_pool, SZ_4G, SZ_4G, NUMA_NO_NODE)) {
+		rc = -ENOMEM;
+		goto err_register;
+	}
+
 	for (i = 0; i < NUM_NFITS; i++) {
 		struct nfit_test *nfit_test;
 		struct platform_device *pdev;
@@ -2894,6 +2920,9 @@ static __init int nfit_test_init(void)
 	return 0;
 
  err_register:
+	if (nfit_pool)
+		gen_pool_destroy(nfit_pool);
+
 	destroy_workqueue(nfit_wq);
 	for (i = 0; i < NUM_NFITS; i++)
 		if (instances[i])
@@ -2917,6 +2946,8 @@ static __exit void nfit_test_exit(void)
 	platform_driver_unregister(&nfit_test_driver);
 	nfit_test_teardown();
 
+	gen_pool_destroy(nfit_pool);
+
 	for (i = 0; i < NUM_NFITS; i++)
 		put_device(&instances[i]->pdev.dev);
 	class_destroy(nfit_test_dimm);
