[mirror_ubuntu-bionic-kernel.git] / include / linux / migrate.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_MIGRATE_H
#define _LINUX_MIGRATE_H

#include <linux/mm.h>
#include <linux/mempolicy.h>
#include <linux/migrate_mode.h>
#include <linux/hugetlb.h>

typedef struct page *new_page_t(struct page *page, unsigned long private,
				int **reason);
typedef void free_page_t(struct page *page, unsigned long private);

/*
 * Return values from addresss_space_operations.migratepage():
 * - negative errno on page migration failure;
 * - zero on page migration success;
 */
#define MIGRATEPAGE_SUCCESS		0

enum migrate_reason {
	MR_COMPACTION,
	MR_MEMORY_FAILURE,
	MR_MEMORY_HOTPLUG,
	MR_SYSCALL,		/* also applies to cpusets */
	MR_MEMPOLICY_MBIND,
	MR_NUMA_MISPLACED,
	MR_CMA,
	MR_TYPES
};

/* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
extern char *migrate_reason_names[MR_TYPES];

static inline struct page *new_page_nodemask(struct page *page,
				int preferred_nid, nodemask_t *nodemask)
{
	gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL;
	unsigned int order = 0;
	struct page *new_page = NULL;

	if (PageHuge(page))
		return alloc_huge_page_nodemask(page_hstate(compound_head(page)),
				preferred_nid, nodemask);

	if (thp_migration_supported() && PageTransHuge(page)) {
		order = HPAGE_PMD_ORDER;
		gfp_mask |= GFP_TRANSHUGE;
	}

	if (PageHighMem(page) || (zone_idx(page_zone(page)) == ZONE_MOVABLE))
		gfp_mask |= __GFP_HIGHMEM;

	new_page = __alloc_pages_nodemask(gfp_mask, order,
				preferred_nid, nodemask);

	if (new_page && PageTransHuge(new_page))
		prep_transhuge_page(new_page);

	return new_page;
}

#ifdef CONFIG_MIGRATION

extern void putback_movable_pages(struct list_head *l);
extern int migrate_page(struct address_space *mapping,
			struct page *newpage, struct page *page,
			enum migrate_mode mode);
extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
		unsigned long private, enum migrate_mode mode, int reason);
extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
extern void putback_movable_page(struct page *page);

extern int migrate_prep(void);
extern int migrate_prep_local(void);
extern void migrate_page_states(struct page *newpage, struct page *page);
extern void migrate_page_copy(struct page *newpage, struct page *page);
extern int migrate_huge_page_move_mapping(struct address_space *mapping,
				  struct page *newpage, struct page *page);
extern int migrate_page_move_mapping(struct address_space *mapping,
		struct page *newpage, struct page *page,
		struct buffer_head *head, enum migrate_mode mode,
		int extra_count);
#else

static inline void putback_movable_pages(struct list_head *l) {}
static inline int migrate_pages(struct list_head *l, new_page_t new,
		free_page_t free, unsigned long private, enum migrate_mode mode,
		int reason)
	{ return -ENOSYS; }
static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
	{ return -EBUSY; }

static inline int migrate_prep(void) { return -ENOSYS; }
static inline int migrate_prep_local(void) { return -ENOSYS; }

static inline void migrate_page_states(struct page *newpage, struct page *page)
{
}

static inline void migrate_page_copy(struct page *newpage,
				     struct page *page) {}

static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
				  struct page *newpage, struct page *page)
{
	return -ENOSYS;
}

#endif /* CONFIG_MIGRATION */

#ifdef CONFIG_COMPACTION
extern int PageMovable(struct page *page);
extern void __SetPageMovable(struct page *page, struct address_space *mapping);
extern void __ClearPageMovable(struct page *page);
#else
static inline int PageMovable(struct page *page) { return 0; };
static inline void __SetPageMovable(struct page *page,
				struct address_space *mapping)
{
}
static inline void __ClearPageMovable(struct page *page)
{
}
#endif

#ifdef CONFIG_NUMA_BALANCING
extern bool pmd_trans_migrating(pmd_t pmd);
extern int migrate_misplaced_page(struct page *page,
				  struct vm_area_struct *vma, int node);
#else
static inline bool pmd_trans_migrating(pmd_t pmd)
{
	return false;
}
static inline int migrate_misplaced_page(struct page *page,
					 struct vm_area_struct *vma, int node)
{
	return -EAGAIN; /* can't migrate now */
}
#endif /* CONFIG_NUMA_BALANCING */

#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
			struct vm_area_struct *vma,
			pmd_t *pmd, pmd_t entry,
			unsigned long address,
			struct page *page, int node);
#else
static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
			struct vm_area_struct *vma,
			pmd_t *pmd, pmd_t entry,
			unsigned long address,
			struct page *page, int node)
{
	return -EAGAIN;
}
#endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/


#ifdef CONFIG_MIGRATION

/*
 * Watch out for PAE architecture, which has an unsigned long, and might not
 * have enough bits to store all physical address and flags. So far we have
 * enough room for all our flags.
 */
#define MIGRATE_PFN_VALID	(1UL << 0)
#define MIGRATE_PFN_MIGRATE	(1UL << 1)
#define MIGRATE_PFN_LOCKED	(1UL << 2)
#define MIGRATE_PFN_WRITE	(1UL << 3)
#define MIGRATE_PFN_DEVICE	(1UL << 4)
#define MIGRATE_PFN_ERROR	(1UL << 5)
#define MIGRATE_PFN_SHIFT	6

static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
{
	if (!(mpfn & MIGRATE_PFN_VALID))
		return NULL;
	return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
}

static inline unsigned long migrate_pfn(unsigned long pfn)
{
	return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
}

/*
 * struct migrate_vma_ops - migrate operation callback
 *
 * @alloc_and_copy: alloc destination memory and copy source memory to it
 * @finalize_and_map: allow caller to map the successfully migrated pages
 *
 *
 * The alloc_and_copy() callback happens once all source pages have been locked,
 * unmapped and checked (checked whether pinned or not). All pages that can be
 * migrated will have an entry in the src array set with the pfn value of the
 * page and with the MIGRATE_PFN_VALID and MIGRATE_PFN_MIGRATE flag set (other
 * flags might be set but should be ignored by the callback).
 *
 * The alloc_and_copy() callback can then allocate destination memory and copy
 * source memory to it for all those entries (ie with MIGRATE_PFN_VALID and
 * MIGRATE_PFN_MIGRATE flag set). Once these are allocated and copied, the
 * callback must update each corresponding entry in the dst array with the pfn
 * value of the destination page and with the MIGRATE_PFN_VALID and
 * MIGRATE_PFN_LOCKED flags set (destination pages must have their struct pages
 * locked, via lock_page()).
 *
 * At this point the alloc_and_copy() callback is done and returns.
 *
 * Note that the callback does not have to migrate all the pages that are
 * marked with MIGRATE_PFN_MIGRATE flag in src array unless this is a migration
 * from device memory to system memory (ie the MIGRATE_PFN_DEVICE flag is also
 * set in the src array entry). If the device driver cannot migrate a device
 * page back to system memory, then it must set the corresponding dst array
 * entry to MIGRATE_PFN_ERROR. This will trigger a SIGBUS if CPU tries to
 * access any of the virtual addresses originally backed by this page. Because
 * a SIGBUS is such a severe result for the userspace process, the device
 * driver should avoid setting MIGRATE_PFN_ERROR unless it is really in an
 * unrecoverable state.
 *
 * For empty entry inside CPU page table (pte_none() or pmd_none() is true) we
 * do set MIGRATE_PFN_MIGRATE flag inside the corresponding source array thus
 * allowing device driver to allocate device memory for those unback virtual
 * address. For this the device driver simply have to allocate device memory
 * and properly set the destination entry like for regular migration. Note that
 * this can still fails and thus inside the device driver must check if the
 * migration was successful for those entry inside the finalize_and_map()
 * callback just like for regular migration.
 *
 * THE alloc_and_copy() CALLBACK MUST NOT CHANGE ANY OF THE SRC ARRAY ENTRIES
 * OR BAD THINGS WILL HAPPEN !
 *
 *
 * The finalize_and_map() callback happens after struct page migration from
 * source to destination (destination struct pages are the struct pages for the
 * memory allocated by the alloc_and_copy() callback).  Migration can fail, and
 * thus the finalize_and_map() allows the driver to inspect which pages were
 * successfully migrated, and which were not. Successfully migrated pages will
 * have the MIGRATE_PFN_MIGRATE flag set for their src array entry.
 *
 * It is safe to update device page table from within the finalize_and_map()
 * callback because both destination and source page are still locked, and the
 * mmap_sem is held in read mode (hence no one can unmap the range being
 * migrated).
 *
 * Once callback is done cleaning up things and updating its page table (if it
 * chose to do so, this is not an obligation) then it returns. At this point,
 * the HMM core will finish up the final steps, and the migration is complete.
 *
 * THE finalize_and_map() CALLBACK MUST NOT CHANGE ANY OF THE SRC OR DST ARRAY
 * ENTRIES OR BAD THINGS WILL HAPPEN !
 */
struct migrate_vma_ops {
	void (*alloc_and_copy)(struct vm_area_struct *vma,
			       const unsigned long *src,
			       unsigned long *dst,
			       unsigned long start,
			       unsigned long end,
			       void *private);
	void (*finalize_and_map)(struct vm_area_struct *vma,
				 const unsigned long *src,
				 const unsigned long *dst,
				 unsigned long start,
				 unsigned long end,
				 void *private);
};

#if defined(CONFIG_MIGRATE_VMA_HELPER)
int migrate_vma(const struct migrate_vma_ops *ops,
		struct vm_area_struct *vma,
		unsigned long start,
		unsigned long end,
		unsigned long *src,
		unsigned long *dst,
		void *private);
#else
static inline int migrate_vma(const struct migrate_vma_ops *ops,
			      struct vm_area_struct *vma,
			      unsigned long start,
			      unsigned long end,
			      unsigned long *src,
			      unsigned long *dst,
			      void *private)
{
	return -EINVAL;
}
#endif /* IS_ENABLED(CONFIG_MIGRATE_VMA_HELPER) */

#endif /* CONFIG_MIGRATION */

#endif /* _LINUX_MIGRATE_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
b20a3503 CL	2	#ifndef _LINUX_MIGRATE_H
	3	#define _LINUX_MIGRATE_H
	4
b20a3503	5	#include <linux/mm.h>
906e0be1	6	#include <linux/mempolicy.h>
6536e312	7	#include <linux/migrate_mode.h>
8b913238	8	#include <linux/hugetlb.h>
b20a3503	9
68711a74 DR	10	typedef struct page new_page_t(struct page page, unsigned long private,
	11	int **reason);
	12	typedef void free_page_t(struct page *page, unsigned long private);
95a402c3	13
78bd5209 RA	14	/*
	15	* Return values from addresss_space_operations.migratepage():
	16	* - negative errno on page migration failure;
	17	* - zero on page migration success;
	18	*/
	19	#define MIGRATEPAGE_SUCCESS 0
d6d86c0a	20
7b2a2d4a MG	21	enum migrate_reason {
	22	MR_COMPACTION,
	23	MR_MEMORY_FAILURE,
	24	MR_MEMORY_HOTPLUG,
	25	MR_SYSCALL, /* also applies to cpusets */
	26	MR_MEMPOLICY_MBIND,
7039e1db	27	MR_NUMA_MISPLACED,
7cd12b4a VB	28	MR_CMA,
7cd12b4a VB	29	MR_TYPES
7b2a2d4a	30	};
78bd5209	31
7cd12b4a VB	32	/* In mm/debug.c; also keep sync with include/trace/events/migrate.h */
	33	extern char *migrate_reason_names[MR_TYPES];
	34
8b913238 MH	35	static inline struct page new_page_nodemask(struct page page,
	36	int preferred_nid, nodemask_t *nodemask)
	37	{
0f556856	38	gfp_t gfp_mask = GFP_USER \| __GFP_MOVABLE \| __GFP_RETRY_MAYFAIL;
8135d892 NH	39	unsigned int order = 0;
8135d892 NH	40	struct page *new_page = NULL;
8b913238 MH	41
	42	if (PageHuge(page))
	43	return alloc_huge_page_nodemask(page_hstate(compound_head(page)),
3e59fcb0	44	preferred_nid, nodemask);
8b913238	45
8135d892 NH	46	if (thp_migration_supported() && PageTransHuge(page)) {
	47	order = HPAGE_PMD_ORDER;
	48	gfp_mask \|= GFP_TRANSHUGE;
	49	}
	50
8b913238 MH	51	if (PageHighMem(page) \|\| (zone_idx(page_zone(page)) == ZONE_MOVABLE))
	52	gfp_mask \|= __GFP_HIGHMEM;
	53
8135d892 NH	54	new_page = __alloc_pages_nodemask(gfp_mask, order,
	55	preferred_nid, nodemask);
	56
40a899ed	57	if (new_page && PageTransHuge(new_page))
8135d892 NH	58	prep_transhuge_page(new_page);
	59
	60	return new_page;
8b913238 MH	61	}
8b913238 MH	62
906e0be1	63	#ifdef CONFIG_MIGRATION
64cdd548	64
5733c7d1	65	extern void putback_movable_pages(struct list_head *l);
9927e388 PJ	66	extern int migrate_page(struct address_space *mapping,
	67	struct page newpage, struct page page,
	68	enum migrate_mode mode);
68711a74	69	extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free,
9c620e2b	70	unsigned long private, enum migrate_mode mode, int reason);
9e5bcd61	71	extern int isolate_movable_page(struct page *page, isolate_mode_t mode);
bda807d4	72	extern void putback_movable_page(struct page *page);
95a402c3	73
b20a3503	74	extern int migrate_prep(void);
748446bb	75	extern int migrate_prep_local(void);
2916ecc0	76	extern void migrate_page_states(struct page newpage, struct page page);
290408d4 NH	77	extern void migrate_page_copy(struct page newpage, struct page page);
	78	extern int migrate_huge_page_move_mapping(struct address_space *mapping,
	79	struct page newpage, struct page page);
36bc08cc GZ	80	extern int migrate_page_move_mapping(struct address_space *mapping,
36bc08cc GZ	81	struct page newpage, struct page page,
8e321fef BL	82	struct buffer_head *head, enum migrate_mode mode,
8e321fef BL	83	int extra_count);
b20a3503	84	#else
64cdd548	85
5733c7d1	86	static inline void putback_movable_pages(struct list_head *l) {}
68711a74 DR	87	static inline int migrate_pages(struct list_head *l, new_page_t new,
	88	free_page_t free, unsigned long private, enum migrate_mode mode,
	89	int reason)
9c620e2b	90	{ return -ENOSYS; }
cbae0170 YX	91	static inline int isolate_movable_page(struct page *page, isolate_mode_t mode)
cbae0170 YX	92	{ return -EBUSY; }
9bf9e89c	93
b20a3503	94	static inline int migrate_prep(void) { return -ENOSYS; }
748446bb	95	static inline int migrate_prep_local(void) { return -ENOSYS; }
b20a3503	96
2916ecc0 JG	97	static inline void migrate_page_states(struct page newpage, struct page page)
	98	{
	99	}
	100
290408d4 NH	101	static inline void migrate_page_copy(struct page *newpage,
	102	struct page *page) {}
	103
6f39ce05	104	static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
290408d4 NH	105	struct page newpage, struct page page)
	106	{
	107	return -ENOSYS;
	108	}
	109
b20a3503	110	#endif /* CONFIG_MIGRATION */
7039e1db	111
dd4123f3 MK	112	#ifdef CONFIG_COMPACTION
	113	extern int PageMovable(struct page *page);
	114	extern void __SetPageMovable(struct page page, struct address_space mapping);
	115	extern void __ClearPageMovable(struct page *page);
	116	#else
	117	static inline int PageMovable(struct page *page) { return 0; };
	118	static inline void __SetPageMovable(struct page *page,
	119	struct address_space *mapping)
	120	{
	121	}
	122	static inline void __ClearPageMovable(struct page *page)
	123	{
	124	}
	125	#endif
	126
7039e1db	127	#ifdef CONFIG_NUMA_BALANCING
de466bd6	128	extern bool pmd_trans_migrating(pmd_t pmd);
1bc115d8 MG	129	extern int migrate_misplaced_page(struct page *page,
1bc115d8 MG	130	struct vm_area_struct *vma, int node);
7039e1db	131	#else
de466bd6 MG	132	static inline bool pmd_trans_migrating(pmd_t pmd)
	133	{
	134	return false;
	135	}
1bc115d8 MG	136	static inline int migrate_misplaced_page(struct page *page,
1bc115d8 MG	137	struct vm_area_struct *vma, int node)
7039e1db PZ	138	{
	139	return -EAGAIN; /* can't migrate now */
	140	}
220018d3	141	#endif /* CONFIG_NUMA_BALANCING */
b32967ff	142
220018d3 MG	143	#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
	144	extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
	145	struct vm_area_struct *vma,
	146	pmd_t *pmd, pmd_t entry,
	147	unsigned long address,
	148	struct page *page, int node);
	149	#else
b32967ff MG	150	static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
	151	struct vm_area_struct *vma,
	152	pmd_t *pmd, pmd_t entry,
	153	unsigned long address,
	154	struct page *page, int node)
	155	{
	156	return -EAGAIN;
	157	}
220018d3	158	#endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
7039e1db	159
8763cb45 JG	160
	161	#ifdef CONFIG_MIGRATION
	162
a5430dda JG	163	/*
	164	* Watch out for PAE architecture, which has an unsigned long, and might not
	165	* have enough bits to store all physical address and flags. So far we have
	166	* enough room for all our flags.
	167	*/
8763cb45 JG	168	#define MIGRATE_PFN_VALID (1UL << 0)
	169	#define MIGRATE_PFN_MIGRATE (1UL << 1)
	170	#define MIGRATE_PFN_LOCKED (1UL << 2)
	171	#define MIGRATE_PFN_WRITE (1UL << 3)
a5430dda JG	172	#define MIGRATE_PFN_DEVICE (1UL << 4)
	173	#define MIGRATE_PFN_ERROR (1UL << 5)
	174	#define MIGRATE_PFN_SHIFT 6
8763cb45 JG	175
	176	static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
	177	{
	178	if (!(mpfn & MIGRATE_PFN_VALID))
	179	return NULL;
	180	return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
	181	}
	182
	183	static inline unsigned long migrate_pfn(unsigned long pfn)
	184	{
	185	return (pfn << MIGRATE_PFN_SHIFT) \| MIGRATE_PFN_VALID;
	186	}
	187
	188	/*
	189	* struct migrate_vma_ops - migrate operation callback
	190	*
	191	* @alloc_and_copy: alloc destination memory and copy source memory to it
	192	* @finalize_and_map: allow caller to map the successfully migrated pages
	193	*
	194	*
	195	* The alloc_and_copy() callback happens once all source pages have been locked,
	196	* unmapped and checked (checked whether pinned or not). All pages that can be
	197	* migrated will have an entry in the src array set with the pfn value of the
	198	* page and with the MIGRATE_PFN_VALID and MIGRATE_PFN_MIGRATE flag set (other
	199	* flags might be set but should be ignored by the callback).
	200	*
	201	* The alloc_and_copy() callback can then allocate destination memory and copy
	202	* source memory to it for all those entries (ie with MIGRATE_PFN_VALID and
	203	* MIGRATE_PFN_MIGRATE flag set). Once these are allocated and copied, the
	204	* callback must update each corresponding entry in the dst array with the pfn
	205	* value of the destination page and with the MIGRATE_PFN_VALID and
	206	* MIGRATE_PFN_LOCKED flags set (destination pages must have their struct pages
	207	* locked, via lock_page()).
	208	*
	209	* At this point the alloc_and_copy() callback is done and returns.
	210	*
	211	* Note that the callback does not have to migrate all the pages that are
	212	* marked with MIGRATE_PFN_MIGRATE flag in src array unless this is a migration
	213	* from device memory to system memory (ie the MIGRATE_PFN_DEVICE flag is also
	214	* set in the src array entry). If the device driver cannot migrate a device
	215	* page back to system memory, then it must set the corresponding dst array
	216	* entry to MIGRATE_PFN_ERROR. This will trigger a SIGBUS if CPU tries to
	217	* access any of the virtual addresses originally backed by this page. Because
	218	* a SIGBUS is such a severe result for the userspace process, the device
	219	* driver should avoid setting MIGRATE_PFN_ERROR unless it is really in an
	220	* unrecoverable state.
	221	*
8315ada7 JG	222	* For empty entry inside CPU page table (pte_none() or pmd_none() is true) we
	223	* do set MIGRATE_PFN_MIGRATE flag inside the corresponding source array thus
	224	* allowing device driver to allocate device memory for those unback virtual
	225	* address. For this the device driver simply have to allocate device memory
	226	* and properly set the destination entry like for regular migration. Note that
	227	* this can still fails and thus inside the device driver must check if the
	228	* migration was successful for those entry inside the finalize_and_map()
	229	* callback just like for regular migration.
	230	*
8763cb45 JG	231	* THE alloc_and_copy() CALLBACK MUST NOT CHANGE ANY OF THE SRC ARRAY ENTRIES
	232	* OR BAD THINGS WILL HAPPEN !
	233	*
	234	*
	235	* The finalize_and_map() callback happens after struct page migration from
	236	* source to destination (destination struct pages are the struct pages for the
	237	* memory allocated by the alloc_and_copy() callback). Migration can fail, and
	238	* thus the finalize_and_map() allows the driver to inspect which pages were
	239	* successfully migrated, and which were not. Successfully migrated pages will
	240	* have the MIGRATE_PFN_MIGRATE flag set for their src array entry.
	241	*
	242	* It is safe to update device page table from within the finalize_and_map()
	243	* callback because both destination and source page are still locked, and the
	244	* mmap_sem is held in read mode (hence no one can unmap the range being
	245	* migrated).
	246	*
	247	* Once callback is done cleaning up things and updating its page table (if it
	248	* chose to do so, this is not an obligation) then it returns. At this point,
	249	* the HMM core will finish up the final steps, and the migration is complete.
	250	*
	251	* THE finalize_and_map() CALLBACK MUST NOT CHANGE ANY OF THE SRC OR DST ARRAY
	252	* ENTRIES OR BAD THINGS WILL HAPPEN !
	253	*/
	254	struct migrate_vma_ops {
	255	void (alloc_and_copy)(struct vm_area_struct vma,
	256	const unsigned long *src,
	257	unsigned long *dst,
	258	unsigned long start,
	259	unsigned long end,
	260	void *private);
	261	void (finalize_and_map)(struct vm_area_struct vma,
	262	const unsigned long *src,
	263	const unsigned long *dst,
	264	unsigned long start,
	265	unsigned long end,
	266	void *private);
	267	};
	268
6b368cd4	269	#if defined(CONFIG_MIGRATE_VMA_HELPER)
8763cb45 JG	270	int migrate_vma(const struct migrate_vma_ops *ops,
	271	struct vm_area_struct *vma,
	272	unsigned long start,
	273	unsigned long end,
	274	unsigned long *src,
	275	unsigned long *dst,
	276	void *private);
6b368cd4 JG	277	#else
	278	static inline int migrate_vma(const struct migrate_vma_ops *ops,
	279	struct vm_area_struct *vma,
	280	unsigned long start,
	281	unsigned long end,
	282	unsigned long *src,
	283	unsigned long *dst,
	284	void *private)
	285	{
	286	return -EINVAL;
	287	}
	288	#endif /* IS_ENABLED(CONFIG_MIGRATE_VMA_HELPER) */
8763cb45 JG	289
	290	#endif /* CONFIG_MIGRATION */
	291
b20a3503	292	#endif /* _LINUX_MIGRATE_H */