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

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

static DEFINE_MUTEX(pgmap_lock);
static RADIX_TREE(pgmap_radix, GFP_KERNEL);
#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)

static unsigned long order_at(struct resource *res, unsigned long pgoff)
{
	unsigned long phys_pgoff = PHYS_PFN(res->start) + pgoff;
	unsigned long nr_pages, mask;

	nr_pages = PHYS_PFN(resource_size(res));
	if (nr_pages == pgoff)
		return ULONG_MAX;

	/*
	 * What is the largest aligned power-of-2 range available from
	 * this resource pgoff to the end of the resource range,
	 * considering the alignment of the current pgoff?
	 */
	mask = phys_pgoff | rounddown_pow_of_two(nr_pages - pgoff);
	if (!mask)
		return ULONG_MAX;

	return find_first_bit(&mask, BITS_PER_LONG);
}

#define foreach_order_pgoff(res, order, pgoff) \
	for (pgoff = 0, order = order_at((res), pgoff); order < ULONG_MAX; \
			pgoff += 1UL << order, order = order_at((res), pgoff))

#if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
int device_private_entry_fault(struct vm_area_struct *vma,
		       unsigned long addr,
		       swp_entry_t entry,
		       unsigned int flags,
		       pmd_t *pmdp)
{
	struct page *page = device_private_entry_to_page(entry);

	/*
	 * The page_fault() callback must migrate page back to system memory
	 * so that CPU can access it. This might fail for various reasons
	 * (device issue, device was unsafely unplugged, ...). When such
	 * error conditions happen, the callback must return VM_FAULT_SIGBUS.
	 *
	 * Note that because memory cgroup charges are accounted to the device
	 * memory, this should never fail because of memory restrictions (but
	 * allocation of regular system page might still fail because we are
	 * out of memory).
	 *
	 * There is a more in-depth description of what that callback can and
	 * cannot do, in include/linux/memremap.h
	 */
	return page->pgmap->page_fault(vma, addr, page, flags, pmdp);
}
EXPORT_SYMBOL(device_private_entry_fault);
#endif /* CONFIG_DEVICE_PRIVATE */

static void pgmap_radix_release(struct resource *res, unsigned long end_pgoff)
{
	unsigned long pgoff, order;

	mutex_lock(&pgmap_lock);
	foreach_order_pgoff(res, order, pgoff) {
		if (pgoff >= end_pgoff)
			break;
		radix_tree_delete(&pgmap_radix, PHYS_PFN(res->start) + pgoff);
	}
	mutex_unlock(&pgmap_lock);

	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;

	for_each_device_pfn(pfn, pgmap)
		put_page(pfn_to_page(pfn));

	if (percpu_ref_tryget_live(pgmap->ref)) {
		dev_WARN(dev, "%s: page mapping is still live!\n", __func__);
		percpu_ref_put(pgmap->ref);
	}

	/* 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;

	mem_hotplug_begin();
	arch_remove_memory(align_start, align_size, pgmap->altmap_valid ?
			&pgmap->altmap : NULL);
	mem_hotplug_done();

	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
	pgmap_radix_release(res, -1);
	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_pgmap
 *
 * Notes:
 * 1/ At a minimum the res, ref and type 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 'dead' before devm_memunmap_pages()
 *    time (or devm release event). The expected order of events is that ref has
 *    been through percpu_ref_kill() before devm_memremap_pages_release(). The
 *    wait for the completion of all references being dropped and
 *    percpu_ref_exit() must occur after devm_memremap_pages_release().
 *
 * 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;
	unsigned long pfn, pgoff, order;
	pgprot_t pgprot = PAGE_KERNEL;
	int error, nid, is_ram;
	struct dev_pagemap *conflict_pgmap;

	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);
		return ERR_PTR(-ENOMEM);
	}

	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);
		return ERR_PTR(-ENOMEM);
	}

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

	if (is_ram == REGION_MIXED) {
		WARN_ONCE(1, "%s attempted on mixed region %pr\n",
				__func__, res);
		return ERR_PTR(-ENXIO);
	}

	if (is_ram == REGION_INTERSECTS)
		return __va(res->start);

	if (!pgmap->ref)
		return ERR_PTR(-EINVAL);

	pgmap->dev = dev;

	mutex_lock(&pgmap_lock);
	error = 0;

	foreach_order_pgoff(res, order, pgoff) {
		error = __radix_tree_insert(&pgmap_radix,
				PHYS_PFN(res->start) + pgoff, order, pgmap);
		if (error) {
			dev_err(dev, "%s: failed: %d\n", __func__, error);
			break;
		}
	}
	mutex_unlock(&pgmap_lock);
	if (error)
		goto err_radix;

	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();
	error = arch_add_memory(nid, align_start, align_size, altmap, false);
	if (!error)
		move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
					align_start >> PAGE_SHIFT,
					align_size >> PAGE_SHIFT, altmap);
	mem_hotplug_done();
	if (error)
		goto err_add_memory;

	for_each_device_pfn(pfn, pgmap) {
		struct page *page = pfn_to_page(pfn);

		/*
		 * ZONE_DEVICE pages union ->lru with a ->pgmap back
		 * pointer.  It is a bug if a ZONE_DEVICE page is ever
		 * freed or placed on a driver-private list.  Seed the
		 * storage with LIST_POISON* values.
		 */
		list_del(&page->lru);
		page->pgmap = pgmap;
		percpu_ref_get(pgmap->ref);
	}

	devm_add_action(dev, devm_memremap_pages_release, pgmap);

	return __va(res->start);

 err_add_memory:
	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
 err_pfn_remap:
 err_radix:
	pgmap_radix_release(res, pgoff);
	return ERR_PTR(error);
}
EXPORT_SYMBOL(devm_memremap_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 = radix_tree_lookup(&pgmap_radix, 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
DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
EXPORT_SYMBOL(devmap_managed_key);
static atomic_t devmap_enable;

/*
 * Toggle the static key for ->page_free() callbacks when dev_pagemap
 * pages go idle.
 */
void dev_pagemap_get_ops(void)
{
	if (atomic_inc_return(&devmap_enable) == 1)
		static_branch_enable(&devmap_managed_key);
}
EXPORT_SYMBOL_GPL(dev_pagemap_get_ops);

void dev_pagemap_put_ops(void)
{
	if (atomic_dec_and_test(&devmap_enable))
		static_branch_disable(&devmap_managed_key);
}
EXPORT_SYMBOL_GPL(dev_pagemap_put_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);

		page->mapping = NULL;
		mem_cgroup_uncharge(page);

		page->pgmap->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. */
9476df7d	3	#include <linux/radix-tree.h>
7d3dcf26	4	#include <linux/device.h>
92281dee	5	#include <linux/types.h>
34c0fd54	6	#include <linux/pfn_t.h>
92281dee DW	7	#include <linux/io.h>
92281dee DW	8	#include <linux/mm.h>
41e94a85	9	#include <linux/memory_hotplug.h>
5042db43 JG	10	#include <linux/swap.h>
5042db43 JG	11	#include <linux/swapops.h>
e7638488	12	#include <linux/wait_bit.h>
92281dee	13
9476df7d DW	14	static DEFINE_MUTEX(pgmap_lock);
	15	static RADIX_TREE(pgmap_radix, GFP_KERNEL);
	16	#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
	17	#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
	18
ab1b597e	19	static unsigned long order_at(struct resource *res, unsigned long pgoff)
9476df7d	20	{
ab1b597e DW	21	unsigned long phys_pgoff = PHYS_PFN(res->start) + pgoff;
ab1b597e DW	22	unsigned long nr_pages, mask;
eb7d78c9	23
ab1b597e DW	24	nr_pages = PHYS_PFN(resource_size(res));
	25	if (nr_pages == pgoff)
	26	return ULONG_MAX;
	27
	28	/*
	29	* What is the largest aligned power-of-2 range available from
	30	* this resource pgoff to the end of the resource range,
	31	* considering the alignment of the current pgoff?
	32	*/
	33	mask = phys_pgoff \| rounddown_pow_of_two(nr_pages - pgoff);
	34	if (!mask)
	35	return ULONG_MAX;
	36
	37	return find_first_bit(&mask, BITS_PER_LONG);
	38	}
	39
	40	#define foreach_order_pgoff(res, order, pgoff) \
	41	for (pgoff = 0, order = order_at((res), pgoff); order < ULONG_MAX; \
	42	pgoff += 1UL << order, order = order_at((res), pgoff))
	43
5042db43 JG	44	#if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
	45	int device_private_entry_fault(struct vm_area_struct *vma,
	46	unsigned long addr,
	47	swp_entry_t entry,
	48	unsigned int flags,
	49	pmd_t *pmdp)
	50	{
	51	struct page *page = device_private_entry_to_page(entry);
	52
	53	/*
	54	* The page_fault() callback must migrate page back to system memory
	55	* so that CPU can access it. This might fail for various reasons
	56	* (device issue, device was unsafely unplugged, ...). When such
	57	* error conditions happen, the callback must return VM_FAULT_SIGBUS.
	58	*
	59	* Note that because memory cgroup charges are accounted to the device
	60	* memory, this should never fail because of memory restrictions (but
	61	* allocation of regular system page might still fail because we are
	62	* out of memory).
	63	*
	64	* There is a more in-depth description of what that callback can and
	65	* cannot do, in include/linux/memremap.h
	66	*/
	67	return page->pgmap->page_fault(vma, addr, page, flags, pmdp);
	68	}
	69	EXPORT_SYMBOL(device_private_entry_fault);
	70	#endif /* CONFIG_DEVICE_PRIVATE */
	71
77dd66a3	72	static void pgmap_radix_release(struct resource *res, unsigned long end_pgoff)
ab1b597e DW	73	{
ab1b597e DW	74	unsigned long pgoff, order;
9476df7d DW	75
9476df7d DW	76	mutex_lock(&pgmap_lock);
77dd66a3 JS	77	foreach_order_pgoff(res, order, pgoff) {
	78	if (pgoff >= end_pgoff)
	79	break;
ab1b597e	80	radix_tree_delete(&pgmap_radix, PHYS_PFN(res->start) + pgoff);
77dd66a3	81	}
9476df7d	82	mutex_unlock(&pgmap_lock);
ab1b597e DW	83
ab1b597e DW	84	synchronize_rcu();
9476df7d DW	85	}
9476df7d DW	86
e7744aa2	87	static unsigned long pfn_first(struct dev_pagemap *pgmap)
5c2c2587	88	{
e7744aa2 LG	89	const struct resource *res = &pgmap->res;
e7744aa2 LG	90	struct vmem_altmap *altmap = &pgmap->altmap;
5c2c2587 DW	91	unsigned long pfn;
	92
	93	pfn = res->start >> PAGE_SHIFT;
e7744aa2	94	if (pgmap->altmap_valid)
5c2c2587 DW	95	pfn += vmem_altmap_offset(altmap);
	96	return pfn;
	97	}
	98
e7744aa2	99	static unsigned long pfn_end(struct dev_pagemap *pgmap)
5c2c2587	100	{
e7744aa2	101	const struct resource *res = &pgmap->res;
5c2c2587 DW	102
	103	return (res->start + resource_size(res)) >> PAGE_SHIFT;
	104	}
	105
949b9325 DW	106	static unsigned long pfn_next(unsigned long pfn)
	107	{
	108	if (pfn % 1024 == 0)
	109	cond_resched();
	110	return pfn + 1;
	111	}
	112
5c2c2587	113	#define for_each_device_pfn(pfn, map) \
949b9325	114	for (pfn = pfn_first(map); pfn < pfn_end(map); pfn = pfn_next(pfn))
5c2c2587	115
e8d51348	116	static void devm_memremap_pages_release(void *data)
41e94a85	117	{
e7744aa2	118	struct dev_pagemap *pgmap = data;
e8d51348	119	struct device *dev = pgmap->dev;
e7744aa2	120	struct resource *res = &pgmap->res;
9476df7d	121	resource_size_t align_start, align_size;
71389703 DW	122	unsigned long pfn;
71389703 DW	123
e7744aa2	124	for_each_device_pfn(pfn, pgmap)
71389703	125	put_page(pfn_to_page(pfn));
9476df7d	126
5c2c2587 DW	127	if (percpu_ref_tryget_live(pgmap->ref)) {
	128	dev_WARN(dev, "%s: page mapping is still live!\n", __func__);
	129	percpu_ref_put(pgmap->ref);
	130	}
	131
41e94a85	132	/* pages are dead and unused, undo the arch mapping */
9476df7d	133	align_start = res->start & ~(SECTION_SIZE - 1);
10a0cd6e JS	134	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
10a0cd6e JS	135	- align_start;
b5d24fda	136
f931ab47	137	mem_hotplug_begin();
e7744aa2 LG	138	arch_remove_memory(align_start, align_size, pgmap->altmap_valid ?
e7744aa2 LG	139	&pgmap->altmap : NULL);
f931ab47	140	mem_hotplug_done();
b5d24fda	141
9049771f	142	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
77dd66a3	143	pgmap_radix_release(res, -1);
e7744aa2 LG	144	dev_WARN_ONCE(dev, pgmap->altmap.alloc,
e7744aa2 LG	145	"%s: failed to free all reserved pages\n", __func__);
9476df7d DW	146	}
9476df7d DW	147
4b94ffdc DW	148	/**
	149	* devm_memremap_pages - remap and provide memmap backing for the given resource
	150	* @dev: hosting device for @res
e8d51348	151	* @pgmap: pointer to a struct dev_pgmap
4b94ffdc	152	*
5c2c2587	153	* Notes:
e8d51348 CH	154	* 1/ At a minimum the res, ref and type members of @pgmap must be initialized
	155	* by the caller before passing it to this function
	156	*
	157	* 2/ The altmap field may optionally be initialized, in which case altmap_valid
	158	* must be set to true
	159	*
	160	* 3/ pgmap.ref must be 'live' on entry and 'dead' before devm_memunmap_pages()
	161	* time (or devm release event). The expected order of events is that ref has
71389703 DW	162	* been through percpu_ref_kill() before devm_memremap_pages_release(). The
	163	* wait for the completion of all references being dropped and
	164	* percpu_ref_exit() must occur after devm_memremap_pages_release().
5c2c2587	165	*
e8d51348	166	* 4/ res is expected to be a host memory range that could feasibly be
5c2c2587 DW	167	* treated as a "System RAM" range, i.e. not a device mmio range, but
5c2c2587 DW	168	* this is not enforced.
4b94ffdc	169	*/
e8d51348	170	void devm_memremap_pages(struct device dev, struct dev_pagemap *pgmap)
41e94a85	171	{
ab1b597e	172	resource_size_t align_start, align_size, align_end;
e8d51348 CH	173	struct vmem_altmap *altmap = pgmap->altmap_valid ?
e8d51348 CH	174	&pgmap->altmap : NULL;
949b9325	175	struct resource *res = &pgmap->res;
ab1b597e	176	unsigned long pfn, pgoff, order;
9049771f	177	pgprot_t pgprot = PAGE_KERNEL;
949b9325	178	int error, nid, is_ram;
15d36fec	179	struct dev_pagemap *conflict_pgmap;
5f29a77c DW	180
	181	align_start = res->start & ~(SECTION_SIZE - 1);
	182	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
	183	- align_start;
15d36fec DJ	184	align_end = align_start + align_size - 1;
	185
	186	conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_start), NULL);
	187	if (conflict_pgmap) {
	188	dev_WARN(dev, "Conflicting mapping in same section\n");
	189	put_dev_pagemap(conflict_pgmap);
	190	return ERR_PTR(-ENOMEM);
	191	}
	192
	193	conflict_pgmap = get_dev_pagemap(PHYS_PFN(align_end), NULL);
	194	if (conflict_pgmap) {
	195	dev_WARN(dev, "Conflicting mapping in same section\n");
	196	put_dev_pagemap(conflict_pgmap);
	197	return ERR_PTR(-ENOMEM);
	198	}
	199
d37a14bb LT	200	is_ram = region_intersects(align_start, align_size,
d37a14bb LT	201	IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
41e94a85 CH	202
	203	if (is_ram == REGION_MIXED) {
	204	WARN_ONCE(1, "%s attempted on mixed region %pr\n",
	205	__func__, res);
	206	return ERR_PTR(-ENXIO);
	207	}
	208
	209	if (is_ram == REGION_INTERSECTS)
	210	return __va(res->start);
	211
e8d51348	212	if (!pgmap->ref)
5c2c2587 DW	213	return ERR_PTR(-EINVAL);
5c2c2587 DW	214
4b94ffdc	215	pgmap->dev = dev;
4b94ffdc	216
9476df7d DW	217	mutex_lock(&pgmap_lock);
9476df7d DW	218	error = 0;
ab1b597e DW	219
ab1b597e DW	220	foreach_order_pgoff(res, order, pgoff) {
ab1b597e	221	error = __radix_tree_insert(&pgmap_radix,
e7744aa2	222	PHYS_PFN(res->start) + pgoff, order, pgmap);
9476df7d DW	223	if (error) {
	224	dev_err(dev, "%s: failed: %d\n", __func__, error);
	225	break;
	226	}
	227	}
	228	mutex_unlock(&pgmap_lock);
	229	if (error)
	230	goto err_radix;
	231
41e94a85 CH	232	nid = dev_to_node(dev);
41e94a85 CH	233	if (nid < 0)
7eff93b7	234	nid = numa_mem_id();
41e94a85	235
9049771f DW	236	error = track_pfn_remap(NULL, &pgprot, PHYS_PFN(align_start), 0,
	237	align_size);
	238	if (error)
	239	goto err_pfn_remap;
	240
f931ab47	241	mem_hotplug_begin();
24e6d5a5	242	error = arch_add_memory(nid, align_start, align_size, altmap, false);
f1dd2cd1 MH	243	if (!error)
	244	move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
	245	align_start >> PAGE_SHIFT,
a99583e7	246	align_size >> PAGE_SHIFT, altmap);
f931ab47	247	mem_hotplug_done();
9476df7d DW	248	if (error)
9476df7d DW	249	goto err_add_memory;
41e94a85	250
e7744aa2	251	for_each_device_pfn(pfn, pgmap) {
5c2c2587 DW	252	struct page *page = pfn_to_page(pfn);
5c2c2587 DW	253
d77a117e DW	254	/*
	255	* ZONE_DEVICE pages union ->lru with a ->pgmap back
	256	* pointer. It is a bug if a ZONE_DEVICE page is ever
	257	* freed or placed on a driver-private list. Seed the
	258	* storage with LIST_POISON* values.
	259	*/
	260	list_del(&page->lru);
5c2c2587	261	page->pgmap = pgmap;
e8d51348	262	percpu_ref_get(pgmap->ref);
5c2c2587	263	}
e8d51348 CH	264
	265	devm_add_action(dev, devm_memremap_pages_release, pgmap);
	266
41e94a85	267	return __va(res->start);
9476df7d DW	268
9476df7d DW	269	err_add_memory:
9049771f DW	270	untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
9049771f DW	271	err_pfn_remap:
9476df7d	272	err_radix:
77dd66a3	273	pgmap_radix_release(res, pgoff);
9476df7d	274	return ERR_PTR(error);
41e94a85 CH	275	}
41e94a85 CH	276	EXPORT_SYMBOL(devm_memremap_pages);
4b94ffdc DW	277
	278	unsigned long vmem_altmap_offset(struct vmem_altmap *altmap)
	279	{
	280	/* number of pfns from base where pfn_to_page() is valid */
	281	return altmap->reserve + altmap->free;
	282	}
	283
	284	void vmem_altmap_free(struct vmem_altmap *altmap, unsigned long nr_pfns)
	285	{
	286	altmap->alloc -= nr_pfns;
	287	}
	288
0822acb8 CH	289	/**
	290	* get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
	291	* @pfn: page frame number to lookup page_map
	292	* @pgmap: optional known pgmap that already has a reference
	293	*
832d7aa0 CH	294	* If @pgmap is non-NULL and covers @pfn it will be returned as-is. If @pgmap
832d7aa0 CH	295	* is non-NULL but does not cover @pfn the reference to it will be released.
0822acb8 CH	296	*/
	297	struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
	298	struct dev_pagemap *pgmap)
	299	{
0822acb8 CH	300	resource_size_t phys = PFN_PHYS(pfn);
	301
	302	/*
832d7aa0	303	* In the cached case we're already holding a live reference.
0822acb8	304	*/
832d7aa0	305	if (pgmap) {
e7744aa2	306	if (phys >= pgmap->res.start && phys <= pgmap->res.end)
832d7aa0 CH	307	return pgmap;
832d7aa0 CH	308	put_dev_pagemap(pgmap);
0822acb8 CH	309	}
	310
	311	/* fall back to slow path lookup */
	312	rcu_read_lock();
e697c5b9	313	pgmap = radix_tree_lookup(&pgmap_radix, PHYS_PFN(phys));
0822acb8 CH	314	if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
	315	pgmap = NULL;
	316	rcu_read_unlock();
	317
	318	return pgmap;
	319	}
e7638488	320	EXPORT_SYMBOL_GPL(get_dev_pagemap);
7b2d55d2	321
e7638488 DW	322	#ifdef CONFIG_DEV_PAGEMAP_OPS
e7638488 DW	323	DEFINE_STATIC_KEY_FALSE(devmap_managed_key);
31c5bda3	324	EXPORT_SYMBOL(devmap_managed_key);
e7638488 DW	325	static atomic_t devmap_enable;
	326
	327	/*
	328	* Toggle the static key for ->page_free() callbacks when dev_pagemap
	329	* pages go idle.
	330	*/
	331	void dev_pagemap_get_ops(void)
	332	{
	333	if (atomic_inc_return(&devmap_enable) == 1)
	334	static_branch_enable(&devmap_managed_key);
	335	}
	336	EXPORT_SYMBOL_GPL(dev_pagemap_get_ops);
	337
	338	void dev_pagemap_put_ops(void)
	339	{
	340	if (atomic_dec_and_test(&devmap_enable))
	341	static_branch_disable(&devmap_managed_key);
	342	}
	343	EXPORT_SYMBOL_GPL(dev_pagemap_put_ops);
	344
	345	void __put_devmap_managed_page(struct page *page)
7b2d55d2 JG	346	{
	347	int count = page_ref_dec_return(page);
	348
	349	/*
	350	* If refcount is 1 then page is freed and refcount is stable as nobody
	351	* holds a reference on the page.
	352	*/
	353	if (count == 1) {
	354	/* Clear Active bit in case of parallel mark_page_accessed */
	355	__ClearPageActive(page);
	356	__ClearPageWaiters(page);
	357
	358	page->mapping = NULL;
c733a828	359	mem_cgroup_uncharge(page);
7b2d55d2 JG	360
	361	page->pgmap->page_free(page, page->pgmap->data);
	362	} else if (!count)
	363	__put_page(page);
	364	}
31c5bda3	365	EXPORT_SYMBOL(__put_devmap_managed_page);
e7638488	366	#endif /* CONFIG_DEV_PAGEMAP_OPS */