[PATCH v4 6/9] dax: plumb hotplug online_type through dax

[Gregory Price]

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

Add 'enum mmop' 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()
to retain backward compatibility and to make explicit to the drivers
what is actually happening underneath.

No functional changes to existing callers.

Signed-off-by: Gregory Price <gourry@xxxxxxxxxx>
---
 drivers/dax/bus.c         | 3 +++
 drivers/dax/bus.h         | 2 ++
 drivers/dax/cxl.c         | 1 +
 drivers/dax/dax-private.h | 3 +++
 drivers/dax/hmem/hmem.c   | 1 +
 drivers/dax/kmem.c        | 5 +++--
 drivers/dax/pmem.c        | 1 +
 7 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 492573b47f66..6611fe399f59 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>
@@ -394,6 +395,7 @@ 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);
 
@@ -1527,6 +1529,7 @@ 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 5909171a4428..c53a9427f8e4 100644
--- a/drivers/dax/bus.h
+++ b/drivers/dax/bus.h
@@ -3,6 +3,7 @@
 #ifndef __DAX_BUS_H__
 #define __DAX_BUS_H__
 #include <linux/device.h>
+#include <linux/memory_hotplug.h>
 #include <linux/platform_device.h>
 #include <linux/range.h>
 #include <linux/workqueue.h>
@@ -26,6 +27,7 @@ struct dev_dax_data {
 	resource_size_t size;
 	int id;
 	bool memmap_on_memory;
+	enum mmop online_type;
 };
 
 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 3ab39b77843d..0eaef700bb2a 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 = mhp_get_default_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 81e4af49e39c..0787325bc8dd 100644
--- a/drivers/dax/dax-private.h
+++ b/drivers/dax/dax-private.h
@@ -8,6 +8,7 @@
 #include <linux/device.h>
 #include <linux/cdev.h>
 #include <linux/idr.h>
+#include <linux/memory_hotplug.h>
 
 /* private routines between core files */
 struct dax_device;
@@ -79,6 +80,7 @@ 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
  */
@@ -95,6 +97,7 @@ struct dev_dax {
 	struct device dev;
 	struct dev_pagemap *pgmap;
 	bool memmap_on_memory;
+	enum mmop 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 af21f66bf872..0ef6e9ae660d 100644
--- a/drivers/dax/hmem/hmem.c
+++ b/drivers/dax/hmem/hmem.c
@@ -37,6 +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 592171ec10f4..41ccb618a146 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -172,8 +172,9 @@ 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,
+				dev_dax->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..a5f987814da5 100644
--- a/drivers/dax/pmem.c
+++ b/drivers/dax/pmem.c
@@ -63,6 +63,7 @@ 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);
-- 
2.54.0