[PATCH 3/9] dax: plumb online_type from dax_kmem creators to hotplug

[Gregory Price <gourry@gourry.net>]

There is no way for drivers leveraging dax_kmem to plumb through a
preferred auto-online policy - the system default policy is forced.

Add online_type field to DAX device creation path to allow drivers
to specify an auto-online policy when using the kmem driver.

Current callers initialize online_type to mhp_get_default_online_type()
which resolves to the system default (memhp_default_online_type).

No functional change to existing drivers.

Cc:David Hildenbrand <david@kernel.org>
Signed-off-by: Gregory Price <gourry@gourry.net>
---
 drivers/cxl/core/region.c |  2 ++
 drivers/cxl/cxl.h         |  1 +
 drivers/dax/bus.c         |  3 +++
 drivers/dax/bus.h         |  1 +
 drivers/dax/cxl.c         |  1 +
 drivers/dax/dax-private.h |  2 ++
 drivers/dax/hmem/hmem.c   |  2 ++
 drivers/dax/kmem.c        | 13 +++++++++++--
 drivers/dax/pmem.c        |  2 ++
 9 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 5bd1213737fa..eef5d5fe3f95 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright(c) 2022 Intel Corporation. All rights reserved. */
 #include <linux/memregion.h>
+#include <linux/memory_hotplug.h>
 #include <linux/genalloc.h>
 #include <linux/debugfs.h>
 #include <linux/device.h>
@@ -3459,6 +3460,7 @@ static int devm_cxl_add_dax_region(struct cxl_region *cxlr)
 	if (IS_ERR(cxlr_dax))
 		return PTR_ERR(cxlr_dax);
 
+	cxlr_dax->online_type = mhp_get_default_online_type();
 	dev = &cxlr_dax->dev;
 	rc = dev_set_name(dev, "dax_region%d", cxlr->id);
 	if (rc)
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index ba17fa86d249..07d57d13f4c7 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -591,6 +591,7 @@ struct cxl_dax_region {
 	struct device dev;
 	struct cxl_region *cxlr;
 	struct range hpa_range;
+	int online_type; /* MMOP_ value for kmem driver */
 };
 
 /**
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index fde29e0ad68b..121a6dd0afe7 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright(c) 2017-2018 Intel Corporation. All rights reserved. */
 #include <linux/memremap.h>
+#include <linux/memory_hotplug.h>
 #include <linux/device.h>
 #include <linux/mutex.h>
 #include <linux/list.h>
@@ -395,6 +396,7 @@ static ssize_t create_store(struct device *dev, struct device_attribute *attr,
 			.size = 0,
 			.id = -1,
 			.memmap_on_memory = false,
+			.online_type = mhp_get_default_online_type(),
 		};
 		struct dev_dax *dev_dax = __devm_create_dev_dax(&data);
 
@@ -1494,6 +1496,7 @@ static struct dev_dax *__devm_create_dev_dax(struct dev_dax_data *data)
 	ida_init(&dev_dax->ida);
 
 	dev_dax->memmap_on_memory = data->memmap_on_memory;
+	dev_dax->online_type = data->online_type;
 
 	inode = dax_inode(dax_dev);
 	dev->devt = inode->i_rdev;
diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h
index cbbf64443098..4ac92a4edfe7 100644
--- a/drivers/dax/bus.h
+++ b/drivers/dax/bus.h
@@ -24,6 +24,7 @@ struct dev_dax_data {
 	resource_size_t size;
 	int id;
 	bool memmap_on_memory;
+	int online_type;	/* MMOP_ value for kmem driver */
 };
 
 struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data);
diff --git a/drivers/dax/cxl.c b/drivers/dax/cxl.c
index 13cd94d32ff7..856a0cd24f3b 100644
--- a/drivers/dax/cxl.c
+++ b/drivers/dax/cxl.c
@@ -27,6 +27,7 @@ static int cxl_dax_region_probe(struct device *dev)
 		.id = -1,
 		.size = range_len(&cxlr_dax->hpa_range),
 		.memmap_on_memory = true,
+		.online_type = cxlr_dax->online_type,
 	};
 
 	return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data));
diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h
index c6ae27c982f4..9559718cc988 100644
--- a/drivers/dax/dax-private.h
+++ b/drivers/dax/dax-private.h
@@ -77,6 +77,7 @@ struct dev_dax_range {
  * @dev: device core
  * @pgmap: pgmap for memmap setup / lifetime (driver owned)
  * @memmap_on_memory: allow kmem to put the memmap in the memory
+ * @online_type: MMOP_* online type for memory hotplug
  * @nr_range: size of @ranges
  * @ranges: range tuples of memory used
  */
@@ -91,6 +92,7 @@ struct dev_dax {
 	struct device dev;
 	struct dev_pagemap *pgmap;
 	bool memmap_on_memory;
+	int online_type;
 	int nr_range;
 	struct dev_dax_range *ranges;
 };
diff --git a/drivers/dax/hmem/hmem.c b/drivers/dax/hmem/hmem.c
index c18451a37e4f..119914b08fd9 100644
--- a/drivers/dax/hmem/hmem.c
+++ b/drivers/dax/hmem/hmem.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/platform_device.h>
+#include <linux/memory_hotplug.h>
 #include <linux/memregion.h>
 #include <linux/module.h>
 #include <linux/dax.h>
@@ -36,6 +37,7 @@ static int dax_hmem_probe(struct platform_device *pdev)
 		.id = -1,
 		.size = region_idle ? 0 : range_len(&mri->range),
 		.memmap_on_memory = false,
+		.online_type = mhp_get_default_online_type(),
 	};
 
 	return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data));
diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index c036e4d0b610..550dc605229e 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -16,6 +16,11 @@
 #include "dax-private.h"
 #include "bus.h"
 
+/* Internal function exported only to kmem module */
+extern int __add_memory_driver_managed(int nid, u64 start, u64 size,
+				       const char *resource_name,
+				       mhp_t mhp_flags, int online_type);
+
 /*
  * Default abstract distance assigned to the NUMA node onlined
  * by DAX/kmem if the low level platform driver didn't initialize
@@ -72,6 +77,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
 	struct dax_kmem_data *data;
 	struct memory_dev_type *mtype;
 	int i, rc, mapped = 0;
+	int online_type;
 	mhp_t mhp_flags;
 	int numa_node;
 	int adist = MEMTIER_DEFAULT_DAX_ADISTANCE;
@@ -134,6 +140,8 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
 		goto err_reg_mgid;
 	data->mgid = rc;
 
+	online_type = dev_dax->online_type;
+
 	for (i = 0; i < dev_dax->nr_range; i++) {
 		struct resource *res;
 		struct range range;
@@ -174,8 +182,9 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
 		 * Ensure that future kexec'd kernels will not treat
 		 * this as RAM automatically.
 		 */
-		rc = add_memory_driver_managed(data->mgid, range.start,
-				range_len(&range), kmem_name, mhp_flags);
+		rc = __add_memory_driver_managed(data->mgid, range.start,
+				range_len(&range), kmem_name, mhp_flags,
+				online_type);
 
 		if (rc) {
 			dev_warn(dev, "mapping%d: %#llx-%#llx memory add failed\n",
diff --git a/drivers/dax/pmem.c b/drivers/dax/pmem.c
index bee93066a849..a5925146b09f 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Copyright(c) 2016 - 2018 Intel Corporation. All rights reserved. */
+#include <linux/memory_hotplug.h>
 #include <linux/memremap.h>
 #include <linux/module.h>
 #include "../nvdimm/pfn.h"
@@ -63,6 +64,7 @@ static struct dev_dax *__dax_pmem_probe(struct device *dev)
 		.pgmap = &pgmap,
 		.size = range_len(&range),
 		.memmap_on_memory = false,
+		.online_type = mhp_get_default_online_type(),
 	};
 
 	return devm_create_dev_dax(&data);
-- 
2.52.0