1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_SWAPOPS_H
3 #define _LINUX_SWAPOPS_H
5 #include <linux/radix-tree.h>
7 #include <linux/mm_types.h>
12 * swapcache pages are stored in the swapper_space radix tree. We want to
13 * get good packing density in that tree, so the index should be dense in
16 * We arrange the `type' and `offset' fields so that `type' is at the seven
17 * high-order bits of the swp_entry_t and `offset' is right-aligned in the
18 * remaining bits. Although `type' itself needs only five bits, we allow for
19 * shmem/tmpfs to shift it all up a further two bits: see swp_to_radix_entry().
21 * swp_entry_t's are *never* stored anywhere in their arch-dependent format.
23 #define SWP_TYPE_SHIFT (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
24 #define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1)
27 * Store a type+offset into a swp_entry_t in an arch-independent format
29 static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset)
33 ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK);
38 * Extract the `type' field from a swp_entry_t. The swp_entry_t is in
39 * arch-independent format
41 static inline unsigned swp_type(swp_entry_t entry)
43 return (entry.val >> SWP_TYPE_SHIFT);
47 * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in
48 * arch-independent format
50 static inline pgoff_t swp_offset(swp_entry_t entry)
52 return entry.val & SWP_OFFSET_MASK;
55 /* check whether a pte points to a swap entry */
56 static inline int is_swap_pte(pte_t pte)
58 return !pte_none(pte) && !pte_present(pte);
62 * Convert the arch-dependent pte representation of a swp_entry_t into an
63 * arch-independent swp_entry_t.
65 static inline swp_entry_t pte_to_swp_entry(pte_t pte)
67 swp_entry_t arch_entry;
69 if (pte_swp_soft_dirty(pte))
70 pte = pte_swp_clear_soft_dirty(pte);
71 if (pte_swp_uffd_wp(pte))
72 pte = pte_swp_clear_uffd_wp(pte);
73 arch_entry = __pte_to_swp_entry(pte);
74 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
78 * Convert the arch-independent representation of a swp_entry_t into the
79 * arch-dependent pte representation.
81 static inline pte_t swp_entry_to_pte(swp_entry_t entry)
83 swp_entry_t arch_entry;
85 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
86 return __swp_entry_to_pte(arch_entry);
89 static inline swp_entry_t radix_to_swp_entry(void *arg)
93 entry.val = xa_to_value(arg);
97 static inline void *swp_to_radix_entry(swp_entry_t entry)
99 return xa_mk_value(entry.val);
102 #if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
103 static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
105 return swp_entry(write ? SWP_DEVICE_WRITE : SWP_DEVICE_READ,
109 static inline bool is_device_private_entry(swp_entry_t entry)
111 int type = swp_type(entry);
112 return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE;
115 static inline void make_device_private_entry_read(swp_entry_t *entry)
117 *entry = swp_entry(SWP_DEVICE_READ, swp_offset(*entry));
120 static inline bool is_write_device_private_entry(swp_entry_t entry)
122 return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
125 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
127 return swp_offset(entry);
130 static inline struct page *device_private_entry_to_page(swp_entry_t entry)
132 return pfn_to_page(swp_offset(entry));
134 #else /* CONFIG_DEVICE_PRIVATE */
135 static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
137 return swp_entry(0, 0);
140 static inline void make_device_private_entry_read(swp_entry_t *entry)
144 static inline bool is_device_private_entry(swp_entry_t entry)
149 static inline bool is_write_device_private_entry(swp_entry_t entry)
154 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
159 static inline struct page *device_private_entry_to_page(swp_entry_t entry)
163 #endif /* CONFIG_DEVICE_PRIVATE */
165 #ifdef CONFIG_MIGRATION
166 static inline swp_entry_t make_migration_entry(struct page *page, int write)
168 BUG_ON(!PageLocked(compound_head(page)));
170 return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ,
174 static inline int is_migration_entry(swp_entry_t entry)
176 return unlikely(swp_type(entry) == SWP_MIGRATION_READ ||
177 swp_type(entry) == SWP_MIGRATION_WRITE);
180 static inline int is_write_migration_entry(swp_entry_t entry)
182 return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE);
185 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
187 return swp_offset(entry);
190 static inline struct page *migration_entry_to_page(swp_entry_t entry)
192 struct page *p = pfn_to_page(swp_offset(entry));
194 * Any use of migration entries may only occur while the
195 * corresponding page is locked
197 BUG_ON(!PageLocked(compound_head(p)));
201 static inline void make_migration_entry_read(swp_entry_t *entry)
203 *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry));
206 extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
208 extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
209 unsigned long address);
210 extern void migration_entry_wait_huge(struct vm_area_struct *vma,
211 struct mm_struct *mm, pte_t *pte);
214 #define make_migration_entry(page, write) swp_entry(0, 0)
215 static inline int is_migration_entry(swp_entry_t swp)
220 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
225 static inline struct page *migration_entry_to_page(swp_entry_t entry)
230 static inline void make_migration_entry_read(swp_entry_t *entryp) { }
231 static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
233 static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
234 unsigned long address) { }
235 static inline void migration_entry_wait_huge(struct vm_area_struct *vma,
236 struct mm_struct *mm, pte_t *pte) { }
237 static inline int is_write_migration_entry(swp_entry_t entry)
244 struct page_vma_mapped_walk;
246 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
247 extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
250 extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
253 extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd);
255 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
257 swp_entry_t arch_entry;
259 if (pmd_swp_soft_dirty(pmd))
260 pmd = pmd_swp_clear_soft_dirty(pmd);
261 arch_entry = __pmd_to_swp_entry(pmd);
262 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
265 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
267 swp_entry_t arch_entry;
269 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
270 return __swp_entry_to_pmd(arch_entry);
273 static inline int is_pmd_migration_entry(pmd_t pmd)
275 return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
278 static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
284 static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
290 static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { }
292 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
294 return swp_entry(0, 0);
297 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
302 static inline int is_pmd_migration_entry(pmd_t pmd)
308 #ifdef CONFIG_MEMORY_FAILURE
310 extern atomic_long_t num_poisoned_pages __read_mostly;
313 * Support for hardware poisoned pages
315 static inline swp_entry_t make_hwpoison_entry(struct page *page)
317 BUG_ON(!PageLocked(page));
318 return swp_entry(SWP_HWPOISON, page_to_pfn(page));
321 static inline int is_hwpoison_entry(swp_entry_t entry)
323 return swp_type(entry) == SWP_HWPOISON;
326 static inline void num_poisoned_pages_inc(void)
328 atomic_long_inc(&num_poisoned_pages);
331 static inline void num_poisoned_pages_dec(void)
333 atomic_long_dec(&num_poisoned_pages);
338 static inline swp_entry_t make_hwpoison_entry(struct page *page)
340 return swp_entry(0, 0);
343 static inline int is_hwpoison_entry(swp_entry_t swp)
348 static inline void num_poisoned_pages_inc(void)
353 #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) || \
354 defined(CONFIG_DEVICE_PRIVATE)
355 static inline int non_swap_entry(swp_entry_t entry)
357 return swp_type(entry) >= MAX_SWAPFILES;
360 static inline int non_swap_entry(swp_entry_t entry)
366 #endif /* CONFIG_MMU */
367 #endif /* _LINUX_SWAPOPS_H */