[linux-2.6-block.git] / kernel / memremap.c

/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright(c) 2015 Intel Corporation. All rights reserved. */
#include <linux/device.h>
#include <linux/io.h>
#include <linux/kasan.h>
#include <linux/memory_hotplug.h>
#include <linux/mm.h>
#include <linux/pfn_t.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/types.h>
#include <linux/wait_bit.h>
#include <linux/xarray.h>

static DEFINE_XARRAY(pgmap_array);
#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)

#ifdef CONFIG_DEV_PAGEMAP_OPS
DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
EXPORT_SYMBOL(devmap_managed_key);
static atomic_t devmap_managed_enable;

static void devmap_managed_enable_put(void *data)
{
	if (atomic_dec_and_test(&devmap_managed_enable))
		static_branch_disable(&devmap_managed_key);
}

static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
{
	if (!pgmap->ops->page_free) {
		WARN(1, "Missing page_free method\n");
		return -EINVAL;
	}

	if (atomic_inc_return(&devmap_managed_enable) == 1)
		static_branch_enable(&devmap_managed_key);
	return devm_add_action_or_reset(dev, devmap_managed_enable_put, NULL);
}
#else
static int devmap_managed_enable_get(struct device *dev, struct dev_pagemap *pgmap)
{
	return -EINVAL;
}
#endif /* CONFIG_DEV_PAGEMAP_OPS */

static void pgmap_array_delete(struct resource *res)
{
	xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end),
			NULL, GFP_KERNEL);
	synchronize_rcu();
}

static unsigned long pfn_first(struct dev_pagemap *pgmap)
{
	const struct resource *res = &pgmap->res;
	struct vmem_altmap *altmap = &pgmap->altmap;
	unsigned long pfn;

	pfn = res->start >> PAGE_SHIFT;
	if (pgmap->altmap_valid)
		pfn += vmem_altmap_offset(altmap);
	return pfn;
}

static unsigned long pfn_end(struct dev_pagemap *pgmap)
{
	const struct resource *res = &pgmap->res;

	return (res->start + resource_size(res)) >> PAGE_SHIFT;
}

static unsigned long pfn_next(unsigned long pfn)
{
	if (pfn % 1024 == 0)
		cond_resched();
	return pfn + 1;
}

#define for_each_device_pfn(pfn, map) \
	for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn))

static void devm_memremap_pages_release(void *data)
{
	struct dev_pagemap *pgmap = data;
	struct device *dev = pgmap->dev;
	struct resource *res = &pgmap->res;
	resource_size_t align_start, align_size;
	unsigned long pfn;
	int nid;

	pgmap->ops->kill(pgmap);
	for_each_device_pfn(pfn, pgmap)
		put_page(pfn_to_page(pfn));
	pgmap->ops->cleanup(pgmap);

	/* pages are dead and unused, undo the arch mapping */
	align_start = res->start & ~(SECTION_SIZE - 1);
	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
		- align_start;

	nid = page_to_nid(pfn_to_page(align_start >> PAGE_SHIFT));

	mem_hotplug_begin();
	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
		pfn = align_start >> PAGE_SHIFT;
		__remove_pages(page_zone(pfn_to_page(pfn)), pfn,
				align_size >> PAGE_SHIFT, NULL);
	} else {
		arch_remove_memory(nid, align_start, align_size,
				pgmap->altmap_valid ? &pgmap->altmap : NULL);
		kasan_remove_zero_shadow(__va(align_start), align_size);
	}
	mem_hotplug_done();

	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
	pgmap_array_delete(res);
	dev_WARN_ONCE(dev, pgmap->altmap.alloc,
		      "%s: failed to free all reserved pages\n", __func__);
}

/**
 * devm_memremap_pages - remap and provide memmap backing for the given resource
 * @dev: hosting device for @res
 * @pgmap: pointer to a struct dev_pagemap
 *
 * Notes:
 * 1/ At a minimum the res, ref and type and ops members of @pgmap must be
 *    initialized by the caller before passing it to this function
 *
 * 2/ The altmap field may optionally be initialized, in which case altmap_valid
 *    must be set to true
 *
 * 3/ pgmap->ref must be 'live' on entry and will be killed and reaped
 *    at devm_memremap_pages_release() time, or if this routine fails.
 *
 * 4/ res is expected to be a host memory range that could feasibly be
 *    treated as a "System RAM" range, i.e. not a device mmio range, but
 *    this is not enforced.
 */
void *devm_memremap_pages(struct device *dev, struct dev_pagemap *pgmap)
{
	resource_size_t align_start, align_size, align_end;
	struct vmem_altmap *altmap = pgmap->altmap_valid ?
			&pgmap->altmap : NULL;
	struct resource *res = &pgmap->res;
	struct dev_pagemap *conflict_pgmap;
	struct mhp_restrictions restrictions = {
		/*
		 * We do not want any optional features only our own memmap
		*/
		.altmap = altmap,
	};
	pgprot_t pgprot = PAGE_KERNEL;
	int error, nid, is_ram;
	bool need_devmap_managed = true;

	switch (pgmap->type) {
	case MEMORY_DEVICE_PRIVATE:
		if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
			WARN(1, "Device private memory not supported\n");
			return ERR_PTR(-EINVAL);
		}
		if (!pgmap->ops || !pgmap->ops->migrate_to_ram) {
			WARN(1, "Missing migrate_to_ram method\n");
			return ERR_PTR(-EINVAL);
		}
		break;
	case MEMORY_DEVICE_FS_DAX:
		if (!IS_ENABLED(CONFIG_ZONE_DEVICE) ||
		    IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
			WARN(1, "File system DAX not supported\n");
			return ERR_PTR(-EINVAL);
		}
		break;
	case MEMORY_DEVICE_DEVDAX:
	case MEMORY_DEVICE_PCI_P2PDMA:
		need_devmap_managed = false;
		break;
	default:
		WARN(1, "Invalid pgmap type %d\n", pgmap->type);
		break;
	}

	if (!pgmap->ref || !pgmap->ops || !pgmap->ops->kill ||
	    !pgmap->ops->cleanup) {
		WARN(1, "Missing reference count teardown definition\n");
		return ERR_PTR(-EINVAL);
	}

	if (need_devmap_managed) {
		error = devmap_managed_enable_get(dev, pgmap);
		if (error)
			return ERR_PTR(error);
	}

	align_start = res->start & ~(SECTION_SIZE - 1);
	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
		- align_start;
	align_end = align_start + align_size - 1;

	conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_start), NULL);
	if (conflict_pgmap) {
		dev_WARN(dev, "Conflicting mapping in same section\n");
		put_dev_pagemap(conflict_pgmap);
		error = -ENOMEM;
		goto err_array;
	}

	conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_end), NULL);
	if (conflict_pgmap) {
		dev_WARN(dev, "Conflicting mapping in same section\n");
		put_dev_pagemap(conflict_pgmap);
		error = -ENOMEM;
		goto err_array;
	}

	is_ram = region_intersects(align_start, align_size,
		IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);

	if (is_ram != REGION_DISJOINT) {
		WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__,
				is_ram == REGION_MIXED ? "mixed" : "ram", res);
		error = -ENXIO;
		goto err_array;
	}

	pgmap->dev = dev;

	error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start),
				PHYS_PFN(res->end), pgmap, GFP_KERNEL));
	if (error)
		goto err_array;

	nid = dev_to_node(dev);
	if (nid < 0)
		nid = numa_mem_id();

	error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(align_start), 0,
			align_size);
	if (error)
		goto err_pfn_remap;

	mem_hotplug_begin();

	/*
	 * For device private memory we call add_pages() as we only need to
	 * allocate and initialize struct page for the device memory. More-
	 * over the device memory is un-accessible thus we do not want to
	 * create a linear mapping for the memory like arch_add_memory()
	 * would do.
	 *
	 * For all other device memory types, which are accessible by
	 * the CPU, we do want the linear mapping and thus use
	 * arch_add_memory().
	 */
	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
		error = add_pages(nid, align_start >> PAGE_SHIFT,
				align_size >> PAGE_SHIFT, &restrictions);
	} else {
		error = kasan_add_zero_shadow(__va(align_start), align_size);
		if (error) {
			mem_hotplug_done();
			goto err_kasan;
		}

		error = arch_add_memory(nid, align_start, align_size,
					&restrictions);
	}

	if (!error) {
		struct zone *zone;

		zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
		move_pfn_range_to_zone(zone, align_start >> PAGE_SHIFT,
				align_size >> PAGE_SHIFT, altmap);
	}

	mem_hotplug_done();
	if (error)
		goto err_add_memory;

	/*
	 * Initialization of the pages has been deferred until now in order
	 * to allow us to do the work while not holding the hotplug lock.
	 */
	memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
				align_start >> PAGE_SHIFT,
				align_size >> PAGE_SHIFT, pgmap);
	percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap));

	error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
			pgmap);
	if (error)
		return ERR_PTR(error);

	return __va(res->start);

 err_add_memory:
	kasan_remove_zero_shadow(__va(align_start), align_size);
 err_kasan:
	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
 err_pfn_remap:
	pgmap_array_delete(res);
 err_array:
	pgmap->ops->kill(pgmap);
	pgmap->ops->cleanup(pgmap);
	return ERR_PTR(error);
}
EXPORT_SYMBOL_GPL(devm_memremap_pages);

void devm_memunmap_pages(struct device *dev, struct dev_pagemap *pgmap)
{
	devm_release_action(dev, devm_memremap_pages_release, pgmap);
}
EXPORT_SYMBOL_GPL(devm_memunmap_pages);

unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
{
	/* number of pfns from base where pfn_to_page() is valid */
	return altmap->reserve + altmap->free;
}

void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
{
	altmap->alloc -= nr_pfns;
}

/**
 * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
 * @pfn: page frame number to lookup page_map
 * @pgmap: optional known pgmap that already has a reference
 *
 * If @pgmap is non-NULL and covers @pfn it will be returned as-is.  If @pgmap
 * is non-NULL but does not cover @pfn the reference to it will be released.
 */
struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
		struct dev_pagemap *pgmap)
{
	resource_size_t phys = PFN_PHYS(pfn);

	/*
	 * In the cached case we're already holding a live reference.
	 */
	if (pgmap) {
		if (phys >= pgmap->res.start && phys <= pgmap->res.end)
			return pgmap;
		put_dev_pagemap(pgmap);
	}

	/* fall back to slow path lookup */
	rcu_read_lock();
	pgmap = xa_load(&pgmap_array, PHYS_PFN(phys));
	if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
		pgmap = NULL;
	rcu_read_unlock();

	return pgmap;
}
EXPORT_SYMBOL_GPL(get_dev_pagemap);

#ifdef CONFIG_DEV_PAGEMAP_OPS
void __put_devmap_managed_page(struct page *page)
{
	int count = page_ref_dec_return(page);

	/*
	 * If refcount is 1 then page is freed and refcount is stable as nobody
	 * holds a reference on the page.
	 */
	if (count == 1) {
		/* Clear Active bit in case of parallel mark_page_accessed */
		__ClearPageActive(page);
		__ClearPageWaiters(page);

		mem_cgroup_uncharge(page);

		page->pgmap->ops->page_free(page, page->pgmap->data);
	} else if (!count)
		__put_page(page);
}
EXPORT_SYMBOL(__put_devmap_managed_page);
#endif /* CONFIG_DEV_PAGEMAP_OPS */
Commit	Line	Data
5981690d DW	1	/* SPDX-License-Identifier: GPL-2.0 */
5981690d DW	2	/* Copyright(c) 2015 Intel Corporation. All rights reserved. */
7d3dcf26	3	#include <linux/device.h>
92281dee	4	#include <linux/io.h>
0207df4f	5	#include <linux/kasan.h>
41e94a85	6	#include <linux/memory_hotplug.h>
bcfa4b72 MW	7	#include <linux/mm.h>
bcfa4b72 MW	8	#include <linux/pfn_t.h>
5042db43 JG	9	#include <linux/swap.h>
5042db43 JG	10	#include <linux/swapops.h>
bcfa4b72	11	#include <linux/types.h>
e7638488	12	#include <linux/wait_bit.h>
bcfa4b72	13	#include <linux/xarray.h>
92281dee	14
bcfa4b72	15	static DEFINE_XARRAY(pgmap_array);
9476df7d DW	16	#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
	17	#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
	18
f6a55e1a CH	19	#ifdef CONFIG_DEV_PAGEMAP_OPS
	20	DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
	21	EXPORT_SYMBOL(devmap_managed_key);
	22	static atomic_t devmap_managed_enable;
	23
	24	static void devmap_managed_enable_put(void *data)
	25	{
	26	if (atomic_dec_and_test(&devmap_managed_enable))
	27	static_branch_disable(&devmap_managed_key);
	28	}
	29
	30	static int devmap_managed_enable_get(struct device dev, struct dev_pagemap pgmap)
	31	{
	32	if (!pgmap->ops->page_free) {
	33	WARN(1, "Missing page_free method\n");
	34	return -EINVAL;
	35	}
	36
	37	if (atomic_inc_return(&devmap_managed_enable) == 1)
	38	static_branch_enable(&devmap_managed_key);
	39	return devm_add_action_or_reset(dev, devmap_managed_enable_put, NULL);
	40	}
	41	#else
	42	static int devmap_managed_enable_get(struct device dev, struct dev_pagemap pgmap)
	43	{
	44	return -EINVAL;
	45	}
	46	#endif /* CONFIG_DEV_PAGEMAP_OPS */
	47
bcfa4b72	48	static void pgmap_array_delete(struct resource *res)
ab1b597e	49	{
bcfa4b72 MW	50	xa_store_range(&pgmap_array, PHYS_PFN(res->start), PHYS_PFN(res->end),
bcfa4b72 MW	51	NULL, GFP_KERNEL);
ab1b597e	52	synchronize_rcu();
9476df7d DW	53	}
9476df7d DW	54
e7744aa2	55	static unsigned long pfn_first(struct dev_pagemap *pgmap)
5c2c2587	56	{
e7744aa2 LG	57	const struct resource *res = &pgmap->res;
e7744aa2 LG	58	struct vmem_altmap *altmap = &pgmap->altmap;
5c2c2587 DW	59	unsigned long pfn;
	60
	61	pfn = res->start >> PAGE_SHIFT;
e7744aa2	62	if (pgmap->altmap_valid)
5c2c2587 DW	63	pfn += vmem_altmap_offset(altmap);
	64	return pfn;
	65	}
	66
e7744aa2	67	static unsigned long pfn_end(struct dev_pagemap *pgmap)
5c2c2587	68	{
e7744aa2	69	const struct resource *res = &pgmap->res;
5c2c2587 DW	70
	71	return (res->start + resource_size(res)) >> PAGE_SHIFT;
	72	}
	73
949b9325 DW	74	static unsigned long pfn_next(unsigned long pfn)
	75	{
	76	if (pfn % 1024 == 0)
	77	cond_resched();
	78	return pfn + 1;
	79	}
	80
5c2c2587	81	#define for_each_device_pfn(pfn, map) \
949b9325	82	for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn))
5c2c2587	83
e8d51348	84	static void devm_memremap_pages_release(void *data)
41e94a85	85	{
e7744aa2	86	struct dev_pagemap *pgmap = data;
e8d51348	87	struct device *dev = pgmap->dev;
e7744aa2	88	struct resource *res = &pgmap->res;
9476df7d	89	resource_size_t align_start, align_size;
71389703	90	unsigned long pfn;
2c2a5af6	91	int nid;
71389703	92
d8668bb0	93	pgmap->ops->kill(pgmap);
e7744aa2	94	for_each_device_pfn(pfn, pgmap)
71389703	95	put_page(pfn_to_page(pfn));
d8668bb0	96	pgmap->ops->cleanup(pgmap);
9476df7d	97
41e94a85	98	/* pages are dead and unused, undo the arch mapping */
9476df7d	99	align_start = res->start & ~(SECTION_SIZE - 1);
10a0cd6e JS	100	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
10a0cd6e JS	101	- align_start;
b5d24fda	102
2c2a5af6 OS	103	nid = page_to_nid(pfn_to_page(align_start >> PAGE_SHIFT));
2c2a5af6 OS	104
f931ab47	105	mem_hotplug_begin();
69324b8f DW	106	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
	107	pfn = align_start >> PAGE_SHIFT;
	108	__remove_pages(page_zone(pfn_to_page(pfn)), pfn,
	109	align_size >> PAGE_SHIFT, NULL);
	110	} else {
2c2a5af6	111	arch_remove_memory(nid, align_start, align_size,
69324b8f DW	112	pgmap->altmap_valid ? &pgmap->altmap : NULL);
	113	kasan_remove_zero_shadow(__va(align_start), align_size);
	114	}
f931ab47	115	mem_hotplug_done();
b5d24fda	116
9049771f	117	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
bcfa4b72	118	pgmap_array_delete(res);
e7744aa2 LG	119	dev_WARN_ONCE(dev, pgmap->altmap.alloc,
e7744aa2 LG	120	"%s: failed to free all reserved pages\n", __func__);
9476df7d DW	121	}
9476df7d DW	122
4b94ffdc DW	123	/**
	124	* devm_memremap_pages - remap and provide memmap backing for the given resource
	125	* @dev: hosting device for @res
a95c90f1	126	* @pgmap: pointer to a struct dev_pagemap
4b94ffdc	127	*
5c2c2587	128	* Notes:
1e240e8d CH	129	* 1/ At a minimum the res, ref and type and ops members of @pgmap must be
1e240e8d CH	130	* initialized by the caller before passing it to this function
e8d51348 CH	131	*
	132	* 2/ The altmap field may optionally be initialized, in which case altmap_valid
	133	* must be set to true
	134	*
50f44ee7 DW	135	* 3/ pgmap->ref must be 'live' on entry and will be killed and reaped
50f44ee7 DW	136	* at devm_memremap_pages_release() time, or if this routine fails.
5c2c2587	137	*
e8d51348	138	* 4/ res is expected to be a host memory range that could feasibly be
5c2c2587 DW	139	* treated as a "System RAM" range, i.e. not a device mmio range, but
5c2c2587 DW	140	* this is not enforced.
4b94ffdc	141	*/
e8d51348	142	void devm_memremap_pages(struct device dev, struct dev_pagemap *pgmap)
41e94a85	143	{
ab1b597e	144	resource_size_t align_start, align_size, align_end;
e8d51348 CH	145	struct vmem_altmap *altmap = pgmap->altmap_valid ?
e8d51348 CH	146	&pgmap->altmap : NULL;
949b9325	147	struct resource *res = &pgmap->res;
966cf44f	148	struct dev_pagemap *conflict_pgmap;
940519f0 MH	149	struct mhp_restrictions restrictions = {
	150	/*
	151	* We do not want any optional features only our own memmap
	152	*/
	153	.altmap = altmap,
	154	};
9049771f	155	pgprot_t pgprot = PAGE_KERNEL;
949b9325	156	int error, nid, is_ram;
f6a55e1a	157	bool need_devmap_managed = true;
5f29a77c	158
3ed2dcdf CH	159	switch (pgmap->type) {
	160	case MEMORY_DEVICE_PRIVATE:
	161	if (!IS_ENABLED(CONFIG_DEVICE_PRIVATE)) {
	162	WARN(1, "Device private memory not supported\n");
	163	return ERR_PTR(-EINVAL);
	164	}
897e6365 CH	165	if (!pgmap->ops \|\| !pgmap->ops->migrate_to_ram) {
	166	WARN(1, "Missing migrate_to_ram method\n");
	167	return ERR_PTR(-EINVAL);
	168	}
3ed2dcdf CH	169	break;
	170	case MEMORY_DEVICE_FS_DAX:
	171	if (!IS_ENABLED(CONFIG_ZONE_DEVICE) \|\|
	172	IS_ENABLED(CONFIG_FS_DAX_LIMITED)) {
	173	WARN(1, "File system DAX not supported\n");
	174	return ERR_PTR(-EINVAL);
	175	}
	176	break;
	177	case MEMORY_DEVICE_DEVDAX:
	178	case MEMORY_DEVICE_PCI_P2PDMA:
f6a55e1a	179	need_devmap_managed = false;
3ed2dcdf CH	180	break;
	181	default:
	182	WARN(1, "Invalid pgmap type %d\n", pgmap->type);
	183	break;
	184	}
	185
1e240e8d CH	186	if (!pgmap->ref \|\| !pgmap->ops \|\| !pgmap->ops->kill \|\|
1e240e8d CH	187	!pgmap->ops->cleanup) {
50f44ee7	188	WARN(1, "Missing reference count teardown definition\n");
a95c90f1	189	return ERR_PTR(-EINVAL);
50f44ee7	190	}
a95c90f1	191
f6a55e1a CH	192	if (need_devmap_managed) {
	193	error = devmap_managed_enable_get(dev, pgmap);
	194	if (error)
	195	return ERR_PTR(error);
	196	}
	197
5f29a77c DW	198	align_start = res->start & ~(SECTION_SIZE - 1);
	199	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
	200	- align_start;
15d36fec DJ	201	align_end = align_start + align_size - 1;
	202
	203	conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_start), NULL);
	204	if (conflict_pgmap) {
	205	dev_WARN(dev, "Conflicting mapping in same section\n");
	206	put_dev_pagemap(conflict_pgmap);
50f44ee7 DW	207	error = -ENOMEM;
50f44ee7 DW	208	goto err_array;
15d36fec DJ	209	}
	210
	211	conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_end), NULL);
	212	if (conflict_pgmap) {
	213	dev_WARN(dev, "Conflicting mapping in same section\n");
	214	put_dev_pagemap(conflict_pgmap);
50f44ee7 DW	215	error = -ENOMEM;
50f44ee7 DW	216	goto err_array;
15d36fec DJ	217	}
15d36fec DJ	218
d37a14bb LT	219	is_ram = region_intersects(align_start, align_size,
d37a14bb LT	220	IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
41e94a85	221
06489cfb DW	222	if (is_ram != REGION_DISJOINT) {
	223	WARN_ONCE(1, "%s attempted on %s region %pr\n", __func__,
	224	is_ram == REGION_MIXED ? "mixed" : "ram", res);
a95c90f1 DW	225	error = -ENXIO;
a95c90f1 DW	226	goto err_array;
41e94a85 CH	227	}
41e94a85 CH	228
4b94ffdc	229	pgmap->dev = dev;
4b94ffdc	230
bcfa4b72 MW	231	error = xa_err(xa_store_range(&pgmap_array, PHYS_PFN(res->start),
bcfa4b72 MW	232	PHYS_PFN(res->end), pgmap, GFP_KERNEL));
9476df7d	233	if (error)
bcfa4b72	234	goto err_array;
9476df7d	235
41e94a85 CH	236	nid = dev_to_node(dev);
41e94a85 CH	237	if (nid < 0)
7eff93b7	238	nid = numa_mem_id();
41e94a85	239
9049771f DW	240	error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(align_start), 0,
	241	align_size);
	242	if (error)
	243	goto err_pfn_remap;
	244
f931ab47	245	mem_hotplug_begin();
69324b8f DW	246
	247	/*
	248	* For device private memory we call add_pages() as we only need to
	249	* allocate and initialize struct page for the device memory. More-
	250	* over the device memory is un-accessible thus we do not want to
	251	* create a linear mapping for the memory like arch_add_memory()
	252	* would do.
	253	*
	254	* For all other device memory types, which are accessible by
	255	* the CPU, we do want the linear mapping and thus use
	256	* arch_add_memory().
	257	*/
	258	if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
	259	error = add_pages(nid, align_start >> PAGE_SHIFT,
940519f0	260	align_size >> PAGE_SHIFT, &restrictions);
69324b8f DW	261	} else {
	262	error = kasan_add_zero_shadow(__va(align_start), align_size);
	263	if (error) {
	264	mem_hotplug_done();
	265	goto err_kasan;
	266	}
	267
940519f0 MH	268	error = arch_add_memory(nid, align_start, align_size,
940519f0 MH	269	&restrictions);
69324b8f DW	270	}
	271
	272	if (!error) {
	273	struct zone *zone;
	274
	275	zone = &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
	276	move_pfn_range_to_zone(zone, align_start >> PAGE_SHIFT,
	277	align_size >> PAGE_SHIFT, altmap);
0207df4f AR	278	}
0207df4f AR	279
f931ab47	280	mem_hotplug_done();
9476df7d DW	281	if (error)
9476df7d DW	282	goto err_add_memory;
41e94a85	283
966cf44f AD	284	/*
	285	* Initialization of the pages has been deferred until now in order
	286	* to allow us to do the work while not holding the hotplug lock.
	287	*/
	288	memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
	289	align_start >> PAGE_SHIFT,
	290	align_size >> PAGE_SHIFT, pgmap);
	291	percpu_ref_get_many(pgmap->ref, pfn_end(pgmap) - pfn_first(pgmap));
e8d51348	292
a95c90f1 DW	293	error = devm_add_action_or_reset(dev, devm_memremap_pages_release,
	294	pgmap);
	295	if (error)
	296	return ERR_PTR(error);
e8d51348	297
41e94a85	298	return __va(res->start);
9476df7d DW	299
9476df7d DW	300	err_add_memory:
0207df4f AR	301	kasan_remove_zero_shadow(__va(align_start), align_size);
0207df4f AR	302	err_kasan:
9049771f DW	303	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
9049771f DW	304	err_pfn_remap:
bcfa4b72 MW	305	pgmap_array_delete(res);
bcfa4b72 MW	306	err_array:
d8668bb0 CH	307	pgmap->ops->kill(pgmap);
d8668bb0 CH	308	pgmap->ops->cleanup(pgmap);
9476df7d	309	return ERR_PTR(error);
41e94a85	310	}
808153e1	311	EXPORT_SYMBOL_GPL(devm_memremap_pages);
4b94ffdc	312
2e3f139e DW	313	void devm_memunmap_pages(struct device dev, struct dev_pagemap pgmap)
	314	{
	315	devm_release_action(dev, devm_memremap_pages_release, pgmap);
	316	}
	317	EXPORT_SYMBOL_GPL(devm_memunmap_pages);
	318
4b94ffdc DW	319	unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
	320	{
	321	/* number of pfns from base where pfn_to_page() is valid */
	322	return altmap->reserve + altmap->free;
	323	}
	324
	325	void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
	326	{
	327	altmap->alloc -= nr_pfns;
	328	}
	329
0822acb8 CH	330	/**
	331	* get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
	332	* @pfn: page frame number to lookup page_map
	333	* @pgmap: optional known pgmap that already has a reference
	334	*
832d7aa0 CH	335	* If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap
832d7aa0 CH	336	* is non-NULL but does not cover @pfn the reference to it will be released.
0822acb8 CH	337	*/
	338	struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
	339	struct dev_pagemap *pgmap)
	340	{
0822acb8 CH	341	resource_size_t phys = PFN_PHYS(pfn);
	342
	343	/*
832d7aa0	344	* In the cached case we're already holding a live reference.
0822acb8	345	*/
832d7aa0	346	if (pgmap) {
e7744aa2	347	if (phys >= pgmap->res.start && phys <= pgmap->res.end)
832d7aa0 CH	348	return pgmap;
832d7aa0 CH	349	put_dev_pagemap(pgmap);
0822acb8 CH	350	}
	351
	352	/* fall back to slow path lookup */
	353	rcu_read_lock();
bcfa4b72	354	pgmap = xa_load(&pgmap_array, PHYS_PFN(phys));
0822acb8 CH	355	if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
	356	pgmap = NULL;
	357	rcu_read_unlock();
	358
	359	return pgmap;
	360	}
e7638488	361	EXPORT_SYMBOL_GPL(get_dev_pagemap);
7b2d55d2	362
e7638488	363	#ifdef CONFIG_DEV_PAGEMAP_OPS
e7638488	364	void __put_devmap_managed_page(struct page *page)
7b2d55d2 JG	365	{
	366	int count = page_ref_dec_return(page);
	367
	368	/*
	369	* If refcount is 1 then page is freed and refcount is stable as nobody
	370	* holds a reference on the page.
	371	*/
	372	if (count == 1) {
	373	/* Clear Active bit in case of parallel mark_page_accessed */
	374	__ClearPageActive(page);
	375	__ClearPageWaiters(page);
	376
c733a828	377	mem_cgroup_uncharge(page);
7b2d55d2	378
1e240e8d	379	page->pgmap->ops->page_free(page, page->pgmap->data);
7b2d55d2 JG	380	} else if (!count)
	381	__put_page(page);
	382	}
31c5bda3	383	EXPORT_SYMBOL(__put_devmap_managed_page);
e7638488	384	#endif /* CONFIG_DEV_PAGEMAP_OPS */