[linux-2.6-block.git] / drivers / dax / kmem.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2016-2019 Intel Corporation. All rights reserved. */
#include <linux/memremap.h>
#include <linux/pagemap.h>
#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 "dax-private.h"
#include "bus.h"

int dev_dax_kmem_probe(struct device *dev)
{
	struct dev_dax *dev_dax = to_dev_dax(dev);
	struct resource *res = &dev_dax->region->res;
	resource_size_t kmem_start;
	resource_size_t kmem_size;
	resource_size_t kmem_end;
	struct resource *new_res;
	int numa_node;
	int rc;

	/*
	 * Ensure good NUMA information for the persistent memory.
	 * Without this check, there is a risk that slow memory
	 * could be mixed in a node with faster memory, causing
	 * unavoidable performance issues.
	 */
	numa_node = dev_dax->target_node;
	if (numa_node < 0) {
		dev_warn(dev, "rejecting DAX region %pR with invalid node: %d\n",
			 res, numa_node);
		return -EINVAL;
	}

	/* Hotplug starting at the beginning of the next block: */
	kmem_start = ALIGN(res->start, memory_block_size_bytes());

	kmem_size = resource_size(res);
	/* Adjust the size down to compensate for moving up kmem_start: */
	kmem_size -= kmem_start - res->start;
	/* Align the size down to cover only complete blocks: */
	kmem_size &= ~(memory_block_size_bytes() - 1);
	kmem_end = kmem_start + kmem_size;

	/* Region is permanently reserved.  Hot-remove not yet implemented. */
	new_res = request_mem_region(kmem_start, kmem_size, dev_name(dev));
	if (!new_res) {
		dev_warn(dev, "could not reserve region [%pa-%pa]\n",
			 &kmem_start, &kmem_end);
		return -EBUSY;
	}

	/*
	 * Set flags appropriate for System RAM.  Leave ..._BUSY clear
	 * so that add_memory() can add a child resource.  Do not
	 * inherit flags from the parent since it may set new flags
	 * unknown to us that will break add_memory() below.
	 */
	new_res->flags = IORESOURCE_SYSTEM_RAM;
	new_res->name = dev_name(dev);

	rc = add_memory(numa_node, new_res->start, resource_size(new_res));
	if (rc) {
		release_resource(new_res);
		kfree(new_res);
		return rc;
	}
	dev_dax->dax_kmem_res = new_res;

	return 0;
}

#ifdef CONFIG_MEMORY_HOTREMOVE
static int dev_dax_kmem_remove(struct device *dev)
{
	struct dev_dax *dev_dax = to_dev_dax(dev);
	struct resource *res = dev_dax->dax_kmem_res;
	resource_size_t kmem_start = res->start;
	resource_size_t kmem_size = resource_size(res);
	int rc;

	/*
	 * We have one shot for removing memory, if some memory blocks were not
	 * offline prior to calling this function remove_memory() will fail, and
	 * there is no way to hotremove this memory until reboot because device
	 * unbind will succeed even if we return failure.
	 */
	rc = remove_memory(dev_dax->target_node, kmem_start, kmem_size);
	if (rc) {
		dev_err(dev,
			"DAX region %pR cannot be hotremoved until the next reboot\n",
			res);
		return rc;
	}

	/* Release and free dax resources */
	release_resource(res);
	kfree(res);
	dev_dax->dax_kmem_res = NULL;

	return 0;
}
#else
static int dev_dax_kmem_remove(struct device *dev)
{
	/*
	 * Without hotremove purposely leak the request_mem_region() for the
	 * device-dax range and return '0' to ->remove() attempts. The removal
	 * of the device from the driver always succeeds, but the region is
	 * permanently pinned as reserved by the unreleased
	 * request_mem_region().
	 */
	return 0;
}
#endif /* CONFIG_MEMORY_HOTREMOVE */

static struct dax_device_driver device_dax_kmem_driver = {
	.drv = {
		.probe = dev_dax_kmem_probe,
		.remove = dev_dax_kmem_remove,
	},
};

static int __init dax_kmem_init(void)
{
	return dax_driver_register(&device_dax_kmem_driver);
}

static void __exit dax_kmem_exit(void)
{
	dax_driver_unregister(&device_dax_kmem_driver);
}

MODULE_AUTHOR("Intel Corporation");
MODULE_LICENSE("GPL v2");
module_init(dax_kmem_init);
module_exit(dax_kmem_exit);
MODULE_ALIAS_DAX_DEVICE(0);
Commit	Line	Data
c221c0b0 DH	1	// SPDX-License-Identifier: GPL-2.0
	2	/* Copyright(c) 2016-2019 Intel Corporation. All rights reserved. */
	3	#include <linux/memremap.h>
	4	#include <linux/pagemap.h>
	5	#include <linux/memory.h>
	6	#include <linux/module.h>
	7	#include <linux/device.h>
	8	#include <linux/pfn_t.h>
	9	#include <linux/slab.h>
	10	#include <linux/dax.h>
	11	#include <linux/fs.h>
	12	#include <linux/mm.h>
	13	#include <linux/mman.h>
	14	#include "dax-private.h"
	15	#include "bus.h"
	16
	17	int dev_dax_kmem_probe(struct device *dev)
	18	{
	19	struct dev_dax *dev_dax = to_dev_dax(dev);
	20	struct resource *res = &dev_dax->region->res;
	21	resource_size_t kmem_start;
	22	resource_size_t kmem_size;
	23	resource_size_t kmem_end;
	24	struct resource *new_res;
	25	int numa_node;
	26	int rc;
	27
	28	/*
	29	* Ensure good NUMA information for the persistent memory.
	30	* Without this check, there is a risk that slow memory
	31	* could be mixed in a node with faster memory, causing
	32	* unavoidable performance issues.
	33	*/
	34	numa_node = dev_dax->target_node;
	35	if (numa_node < 0) {
	36	dev_warn(dev, "rejecting DAX region %pR with invalid node: %d\n",
	37	res, numa_node);
	38	return -EINVAL;
	39	}
	40
	41	/* Hotplug starting at the beginning of the next block: */
	42	kmem_start = ALIGN(res->start, memory_block_size_bytes());
	43
	44	kmem_size = resource_size(res);
	45	/* Adjust the size down to compensate for moving up kmem_start: */
	46	kmem_size -= kmem_start - res->start;
	47	/* Align the size down to cover only complete blocks: */
	48	kmem_size &= ~(memory_block_size_bytes() - 1);
	49	kmem_end = kmem_start + kmem_size;
	50
	51	/* Region is permanently reserved. Hot-remove not yet implemented. */
	52	new_res = request_mem_region(kmem_start, kmem_size, dev_name(dev));
	53	if (!new_res) {
	54	dev_warn(dev, "could not reserve region [%pa-%pa]\n",
	55	&kmem_start, &kmem_end);
	56	return -EBUSY;
	57	}
	58
	59	/*
	60	* Set flags appropriate for System RAM. Leave ..._BUSY clear
	61	* so that add_memory() can add a child resource. Do not
	62	* inherit flags from the parent since it may set new flags
	63	* unknown to us that will break add_memory() below.
	64	*/
65	new_res->flags = IORESOURCE_SYSTEM_RAM;
66	new_res->name = dev_name(dev);
67
68	rc = add_memory(numa_node, new_res->start, resource_size(new_res));
31e4ca92 PT	69	if (rc) {
	70	release_resource(new_res);
	71	kfree(new_res);
c221c0b0	72	return rc;
31e4ca92	73	}
9f960da7	74	dev_dax->dax_kmem_res = new_res;
c221c0b0 DH	75
	76	return 0;
	77	}
	78
9f960da7 PT	79	#ifdef CONFIG_MEMORY_HOTREMOVE
	80	static int dev_dax_kmem_remove(struct device *dev)
	81	{
	82	struct dev_dax *dev_dax = to_dev_dax(dev);
	83	struct resource *res = dev_dax->dax_kmem_res;
	84	resource_size_t kmem_start = res->start;
	85	resource_size_t kmem_size = resource_size(res);
	86	int rc;
	87
	88	/*
	89	* We have one shot for removing memory, if some memory blocks were not
	90	* offline prior to calling this function remove_memory() will fail, and
	91	* there is no way to hotremove this memory until reboot because device
	92	* unbind will succeed even if we return failure.
	93	*/
	94	rc = remove_memory(dev_dax->target_node, kmem_start, kmem_size);
	95	if (rc) {
	96	dev_err(dev,
	97	"DAX region %pR cannot be hotremoved until the next reboot\n",
	98	res);
	99	return rc;
	100	}
	101
	102	/* Release and free dax resources */
	103	release_resource(res);
	104	kfree(res);
	105	dev_dax->dax_kmem_res = NULL;
	106
	107	return 0;
	108	}
	109	#else
c221c0b0 DH	110	static int dev_dax_kmem_remove(struct device *dev)
	111	{
	112	/*
9f960da7 PT	113	* Without hotremove purposely leak the request_mem_region() for the
	114	* device-dax range and return '0' to ->remove() attempts. The removal
	115	* of the device from the driver always succeeds, but the region is
	116	* permanently pinned as reserved by the unreleased
c221c0b0 DH	117	* request_mem_region().
	118	*/
	119	return 0;
	120	}
9f960da7	121	#endif /* CONFIG_MEMORY_HOTREMOVE */
c221c0b0 DH	122
	123	static struct dax_device_driver device_dax_kmem_driver = {
	124	.drv = {
	125	.probe = dev_dax_kmem_probe,
	126	.remove = dev_dax_kmem_remove,
	127	},
	128	};
	129
	130	static int __init dax_kmem_init(void)
	131	{
	132	return dax_driver_register(&device_dax_kmem_driver);
	133	}
	134
	135	static void __exit dax_kmem_exit(void)
	136	{
	137	dax_driver_unregister(&device_dax_kmem_driver);
	138	}
	139
	140	MODULE_AUTHOR("Intel Corporation");
	141	MODULE_LICENSE("GPL v2");
	142	module_init(dax_kmem_init);
	143	module_exit(dax_kmem_exit);
	144	MODULE_ALIAS_DAX_DEVICE(0);