1 files changed, 103 insertions, 15 deletions

diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index ac231cc36359..c036e4d0b610 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -5,15 +5,24 @@
 #include <linux/memory.h>
 #include <linux/module.h>
 #include <linux/device.h>
-#include <linux/pfn_t.h>
 #include <linux/slab.h>
 #include <linux/dax.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/mman.h>
+#include <linux/memory-tiers.h>
+#include <linux/memory_hotplug.h>
+#include <linux/string_helpers.h>
 #include "dax-private.h"
 #include "bus.h"
 
+/*
+ * Default abstract distance assigned to the NUMA node onlined
+ * by DAX/kmem if the low level platform driver didn't initialize
+ * one for this NUMA node.
+ */
+#define MEMTIER_DEFAULT_DAX_ADISTANCE	(MEMTIER_ADISTANCE_DRAM * 5)
+
 /* Memory resource name used for add_memory_driver_managed(). */
 static const char *kmem_name;
 /* Set if any memory will remain added when the driver will be unloaded. */
@@ -37,16 +46,35 @@ static int dax_kmem_range(struct dev_dax *dev_dax, int i, struct range *r)
 
 struct dax_kmem_data {
 	const char *res_name;
+	int mgid;
 	struct resource *res[];
 };
 
+static DEFINE_MUTEX(kmem_memory_type_lock);
+static LIST_HEAD(kmem_memory_types);
+
+static struct memory_dev_type *kmem_find_alloc_memory_type(int adist)
+{
+	guard(mutex)(&kmem_memory_type_lock);
+	return mt_find_alloc_memory_type(adist, &kmem_memory_types);
+}
+
+static void kmem_put_memory_types(void)
+{
+	guard(mutex)(&kmem_memory_type_lock);
+	mt_put_memory_types(&kmem_memory_types);
+}
+
 static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
 {
 	struct device *dev = &dev_dax->dev;
+	unsigned long total_len = 0, orig_len = 0;
 	struct dax_kmem_data *data;
-	int rc = -ENOMEM;
-	int i, mapped = 0;
+	struct memory_dev_type *mtype;
+	int i, rc, mapped = 0;
+	mhp_t mhp_flags;
 	int numa_node;
+	int adist = MEMTIER_DEFAULT_DAX_ADISTANCE;
 
 	/*
 	 * Ensure good NUMA information for the persistent memory.
@@ -61,24 +89,58 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
 		return -EINVAL;
 	}
 
+	mt_calc_adistance(numa_node, &adist);
+	mtype = kmem_find_alloc_memory_type(adist);
+	if (IS_ERR(mtype))
+		return PTR_ERR(mtype);
+
+	for (i = 0; i < dev_dax->nr_range; i++) {
+		struct range range;
+
+		orig_len += range_len(&dev_dax->ranges[i].range);
+		rc = dax_kmem_range(dev_dax, i, &range);
+		if (rc) {
+			dev_info(dev, "mapping%d: %#llx-%#llx too small after alignment\n",
+					i, range.start, range.end);
+			continue;
+		}
+		total_len += range_len(&range);
+	}
+
+	if (!total_len) {
+		dev_warn(dev, "rejecting DAX region without any memory after alignment\n");
+		return -EINVAL;
+	} else if (total_len != orig_len) {
+		char buf[16];
+
+		string_get_size(orig_len - total_len, 1, STRING_UNITS_2,
+				buf, sizeof(buf));
+		dev_warn(dev, "DAX region truncated by %s due to alignment\n", buf);
+	}
+
+	init_node_memory_type(numa_node, mtype);
+
+	rc = -ENOMEM;
 	data = kzalloc(struct_size(data, res, dev_dax->nr_range), GFP_KERNEL);
 	if (!data)
-		return -ENOMEM;
+		goto err_dax_kmem_data;
 
 	data->res_name = kstrdup(dev_name(dev), GFP_KERNEL);
 	if (!data->res_name)
 		goto err_res_name;
 
+	rc = memory_group_register_static(numa_node, PFN_UP(total_len));
+	if (rc < 0)
+		goto err_reg_mgid;
+	data->mgid = rc;
+
 	for (i = 0; i < dev_dax->nr_range; i++) {
 		struct resource *res;
 		struct range range;
 
 		rc = dax_kmem_range(dev_dax, i, &range);
-		if (rc) {
-			dev_info(dev, "mapping%d: %#llx-%#llx too small after alignment\n",
-					i, range.start, range.end);
+		if (rc)
 			continue;
-		}
 
 		/* Region is permanently reserved if hotremove fails. */
 		res = request_mem_region(range.start, range_len(&range), data->res_name);
@@ -104,17 +166,21 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
 		 */
 		res->flags = IORESOURCE_SYSTEM_RAM;
 
+		mhp_flags = MHP_NID_IS_MGID;
+		if (dev_dax->memmap_on_memory)
+			mhp_flags |= MHP_MEMMAP_ON_MEMORY;
+
 		/*
 		 * Ensure that future kexec'd kernels will not treat
 		 * this as RAM automatically.
 		 */
-		rc = add_memory_driver_managed(numa_node, range.start,
-				range_len(&range), kmem_name, MHP_NONE);
+		rc = add_memory_driver_managed(data->mgid, range.start,
+				range_len(&range), kmem_name, mhp_flags);
 
 		if (rc) {
 			dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n",
 					i, range.start, range.end);
-			release_resource(res);
+			remove_resource(res);
 			kfree(res);
 			data->res[i] = NULL;
 			if (mapped)
@@ -129,9 +195,13 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
 	return 0;
 
 err_request_mem:
+	memory_group_unregister(data->mgid);
+err_reg_mgid:
 	kfree(data->res_name);
 err_res_name:
 	kfree(data);
+err_dax_kmem_data:
+	clear_node_memory_type(numa_node, mtype);
 	return rc;
 }
 
@@ -139,6 +209,7 @@ err_res_name:
 static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
 {
 	int i, success = 0;
+	int node = dev_dax->target_node;
 	struct device *dev = &dev_dax->dev;
 	struct dax_kmem_data *data = dev_get_drvdata(dev);
 
@@ -156,10 +227,9 @@ static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
 		if (rc)
 			continue;
 
-		rc = remove_memory(dev_dax->target_node, range.start,
-				range_len(&range));
+		rc = remove_memory(range.start, range_len(&range));
 		if (rc == 0) {
-			release_resource(data->res[i]);
+			remove_resource(data->res[i]);
 			kfree(data->res[i]);
 			data->res[i] = NULL;
 			success++;
@@ -172,9 +242,18 @@ static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
 	}
 
 	if (success >= dev_dax->nr_range) {
+		memory_group_unregister(data->mgid);
 		kfree(data->res_name);
 		kfree(data);
 		dev_set_drvdata(dev, NULL);
+		/*
+		 * Clear the memtype association on successful unplug.
+		 * If not, we have memory blocks left which can be
+		 * offlined/onlined later. We need to keep memory_dev_type
+		 * for that. This implies this reference will be around
+		 * till next reboot.
+		 */
+		clear_node_memory_type(node, NULL);
 	}
 }
 #else
@@ -194,6 +273,7 @@ static void dev_dax_kmem_remove(struct dev_dax *dev_dax)
 static struct dax_device_driver device_dax_kmem_driver = {
 	.probe = dev_dax_kmem_probe,
 	.remove = dev_dax_kmem_remove,
+	.type = DAXDRV_KMEM_TYPE,
 };
 
 static int __init dax_kmem_init(void)
@@ -207,7 +287,13 @@ static int __init dax_kmem_init(void)
 
 	rc = dax_driver_register(&device_dax_kmem_driver);
 	if (rc)
-		kfree_const(kmem_name);
+		goto error_dax_driver;
+
+	return rc;
+
+error_dax_driver:
+	kmem_put_memory_types();
+	kfree_const(kmem_name);
 	return rc;
 }
 
@@ -216,9 +302,11 @@ static void __exit dax_kmem_exit(void)
 	dax_driver_unregister(&device_dax_kmem_driver);
 	if (!any_hotremove_failed)
 		kfree_const(kmem_name);
+	kmem_put_memory_types();
 }
 
 MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("KMEM DAX: map dax-devices as System-RAM");
 MODULE_LICENSE("GPL v2");
 module_init(dax_kmem_init);
 module_exit(dax_kmem_exit);