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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SWAPOPS_H
#define _LINUX_SWAPOPS_H
#include <linux/radix-tree.h>
#include <linux/bug.h>
#include <linux/mm_types.h>
#ifdef CONFIG_MMU
/*
* swapcache pages are stored in the swapper_space radix tree. We want to
* get good packing density in that tree, so the index should be dense in
* the low-order bits.
*
* We arrange the `type' and `offset' fields so that `type' is at the seven
* high-order bits of the swp_entry_t and `offset' is right-aligned in the
* remaining bits. Although `type' itself needs only five bits, we allow for
* shmem/tmpfs to shift it all up a further two bits: see swp_to_radix_entry().
*
* swp_entry_t's are *never* stored anywhere in their arch-dependent format.
*/
#define SWP_TYPE_SHIFT (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
#define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1)
/*
* Store a type+offset into a swp_entry_t in an arch-independent format
*/
static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset)
{
swp_entry_t ret;
ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK);
return ret;
}
/*
* Extract the `type' field from a swp_entry_t. The swp_entry_t is in
* arch-independent format
*/
static inline unsigned swp_type(swp_entry_t entry)
{
return (entry.val >> SWP_TYPE_SHIFT);
}
/*
* Extract the `offset' field from a swp_entry_t. The swp_entry_t is in
* arch-independent format
*/
static inline pgoff_t swp_offset(swp_entry_t entry)
{
return entry.val & SWP_OFFSET_MASK;
}
/* check whether a pte points to a swap entry */
static inline int is_swap_pte(pte_t pte)
{
return !pte_none(pte) && !pte_present(pte);
}
/*
* Convert the arch-dependent pte representation of a swp_entry_t into an
* arch-independent swp_entry_t.
*/
static inline swp_entry_t pte_to_swp_entry(pte_t pte)
{
swp_entry_t arch_entry;
if (pte_swp_soft_dirty(pte))
pte = pte_swp_clear_soft_dirty(pte);
arch_entry = __pte_to_swp_entry(pte);
return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
}
/*
* Convert the arch-independent representation of a swp_entry_t into the
* arch-dependent pte representation.
*/
static inline pte_t swp_entry_to_pte(swp_entry_t entry)
{
swp_entry_t arch_entry;
arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
return __swp_entry_to_pte(arch_entry);
}
static inline swp_entry_t radix_to_swp_entry(void *arg)
{
swp_entry_t entry;
entry.val = xa_to_value(arg);
return entry;
}
static inline void *swp_to_radix_entry(swp_entry_t entry)
{
return xa_mk_value(entry.val);
}
#if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
{
return swp_entry(write ? SWP_DEVICE_WRITE : SWP_DEVICE_READ,
page_to_pfn(page));
}
static inline bool is_device_private_entry(swp_entry_t entry)
{
int type = swp_type(entry);
return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE;
}
static inline void make_device_private_entry_read(swp_entry_t *entry)
{
*entry = swp_entry(SWP_DEVICE_READ, swp_offset(*entry));
}
static inline bool is_write_device_private_entry(swp_entry_t entry)
{
return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
}
static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
{
return swp_offset(entry);
}
static inline struct page *device_private_entry_to_page(swp_entry_t entry)
{
return pfn_to_page(swp_offset(entry));
}
#else /* CONFIG_DEVICE_PRIVATE */
static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
{
return swp_entry(0, 0);
}
static inline void make_device_private_entry_read(swp_entry_t *entry)
{
}
static inline bool is_device_private_entry(swp_entry_t entry)
{
return false;
}
static inline bool is_write_device_private_entry(swp_entry_t entry)
{
return false;
}
static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
{
return 0;
}
static inline struct page *device_private_entry_to_page(swp_entry_t entry)
{
return NULL;
}
#endif /* CONFIG_DEVICE_PRIVATE */
#ifdef CONFIG_MIGRATION
static inline swp_entry_t make_migration_entry(struct page *page, int write)
{
BUG_ON(!PageLocked(compound_head(page)));
return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ,
page_to_pfn(page));
}
static inline int is_migration_entry(swp_entry_t entry)
{
return unlikely(swp_type(entry) == SWP_MIGRATION_READ ||
swp_type(entry) == SWP_MIGRATION_WRITE);
}
static inline int is_write_migration_entry(swp_entry_t entry)
{
return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE);
}
static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
{
return swp_offset(entry);
}
static inline struct page *migration_entry_to_page(swp_entry_t entry)
{
struct page *p = pfn_to_page(swp_offset(entry));
/*
* Any use of migration entries may only occur while the
* corresponding page is locked
*/
BUG_ON(!PageLocked(compound_head(p)));
return p;
}
static inline void make_migration_entry_read(swp_entry_t *entry)
{
*entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry));
}
extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
spinlock_t *ptl);
extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
unsigned long address);
extern void migration_entry_wait_huge(struct vm_area_struct *vma,
struct mm_struct *mm, pte_t *pte);
#else
#define make_migration_entry(page, write) swp_entry(0, 0)
static inline int is_migration_entry(swp_entry_t swp)
{
return 0;
}
static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
{
return 0;
}
static inline struct page *migration_entry_to_page(swp_entry_t entry)
{
return NULL;
}
static inline void make_migration_entry_read(swp_entry_t *entryp) { }
static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
spinlock_t *ptl) { }
static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
unsigned long address) { }
static inline void migration_entry_wait_huge(struct vm_area_struct *vma,
struct mm_struct *mm, pte_t *pte) { }
static inline int is_write_migration_entry(swp_entry_t entry)
{
return 0;
}
#endif
struct page_vma_mapped_walk;
#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
struct page *page);
extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
struct page *new);
extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd);
static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
{
swp_entry_t arch_entry;
if (pmd_swp_soft_dirty(pmd))
pmd = pmd_swp_clear_soft_dirty(pmd);
arch_entry = __pmd_to_swp_entry(pmd);
return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
}
static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
{
swp_entry_t arch_entry;
arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
return __swp_entry_to_pmd(arch_entry);
}
static inline int is_pmd_migration_entry(pmd_t pmd)
{
return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
}
#else
static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
struct page *page)
{
BUILD_BUG();
}
static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
struct page *new)
{
BUILD_BUG();
}
static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { }
static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
{
return swp_entry(0, 0);
}
static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
{
return __pmd(0);
}
static inline int is_pmd_migration_entry(pmd_t pmd)
{
return 0;
}
#endif
#ifdef CONFIG_MEMORY_FAILURE
extern atomic_long_t num_poisoned_pages __read_mostly;
/*
* Support for hardware poisoned pages
*/
static inline swp_entry_t make_hwpoison_entry(struct page *page)
{
BUG_ON(!PageLocked(page));
return swp_entry(SWP_HWPOISON, page_to_pfn(page));
}
static inline int is_hwpoison_entry(swp_entry_t entry)
{
return swp_type(entry) == SWP_HWPOISON;
}
static inline void num_poisoned_pages_inc(void)
{
atomic_long_inc(&num_poisoned_pages);
}
static inline void num_poisoned_pages_dec(void)
{
atomic_long_dec(&num_poisoned_pages);
}
#else
static inline swp_entry_t make_hwpoison_entry(struct page *page)
{
return swp_entry(0, 0);
}
static inline int is_hwpoison_entry(swp_entry_t swp)
{
return 0;
}
static inline void num_poisoned_pages_inc(void)
{
}
#endif
#if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) || \
defined(CONFIG_DEVICE_PRIVATE)
static inline int non_swap_entry(swp_entry_t entry)
{
return swp_type(entry) >= MAX_SWAPFILES;
}
#else
static inline int non_swap_entry(swp_entry_t entry)
{
return 0;
}
#endif
#endif /* CONFIG_MMU */
#endif /* _LINUX_SWAPOPS_H */
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