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)
26 /* Clear all flags but only keep swp_entry_t related information */
27 static inline pte_t pte_swp_clear_flags(pte_t pte)
29 if (pte_swp_soft_dirty(pte))
30 pte = pte_swp_clear_soft_dirty(pte);
31 if (pte_swp_uffd_wp(pte))
32 pte = pte_swp_clear_uffd_wp(pte);
37 * Store a type+offset into a swp_entry_t in an arch-independent format
39 static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset)
43 ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK);
48 * Extract the `type' field from a swp_entry_t. The swp_entry_t is in
49 * arch-independent format
51 static inline unsigned swp_type(swp_entry_t entry)
53 return (entry.val >> SWP_TYPE_SHIFT);
57 * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in
58 * arch-independent format
60 static inline pgoff_t swp_offset(swp_entry_t entry)
62 return entry.val & SWP_OFFSET_MASK;
65 /* check whether a pte points to a swap entry */
66 static inline int is_swap_pte(pte_t pte)
68 return !pte_none(pte) && !pte_present(pte);
72 * Convert the arch-dependent pte representation of a swp_entry_t into an
73 * arch-independent swp_entry_t.
75 static inline swp_entry_t pte_to_swp_entry(pte_t pte)
77 swp_entry_t arch_entry;
79 pte = pte_swp_clear_flags(pte);
80 arch_entry = __pte_to_swp_entry(pte);
81 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
85 * Convert the arch-independent representation of a swp_entry_t into the
86 * arch-dependent pte representation.
88 static inline pte_t swp_entry_to_pte(swp_entry_t entry)
90 swp_entry_t arch_entry;
92 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
93 return __swp_entry_to_pte(arch_entry);
96 static inline swp_entry_t radix_to_swp_entry(void *arg)
100 entry.val = xa_to_value(arg);
104 static inline void *swp_to_radix_entry(swp_entry_t entry)
106 return xa_mk_value(entry.val);
109 #if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
110 static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
112 return swp_entry(write ? SWP_DEVICE_WRITE : SWP_DEVICE_READ,
116 static inline bool is_device_private_entry(swp_entry_t entry)
118 int type = swp_type(entry);
119 return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE;
122 static inline void make_device_private_entry_read(swp_entry_t *entry)
124 *entry = swp_entry(SWP_DEVICE_READ, swp_offset(*entry));
127 static inline bool is_write_device_private_entry(swp_entry_t entry)
129 return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
132 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
134 return swp_offset(entry);
137 static inline struct page *device_private_entry_to_page(swp_entry_t entry)
139 return pfn_to_page(swp_offset(entry));
141 #else /* CONFIG_DEVICE_PRIVATE */
142 static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
144 return swp_entry(0, 0);
147 static inline void make_device_private_entry_read(swp_entry_t *entry)
151 static inline bool is_device_private_entry(swp_entry_t entry)
156 static inline bool is_write_device_private_entry(swp_entry_t entry)
161 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
166 static inline struct page *device_private_entry_to_page(swp_entry_t entry)
170 #endif /* CONFIG_DEVICE_PRIVATE */
172 #ifdef CONFIG_MIGRATION
173 static inline swp_entry_t make_migration_entry(struct page *page, int write)
175 BUG_ON(!PageLocked(compound_head(page)));
177 return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ,
181 static inline int is_migration_entry(swp_entry_t entry)
183 return unlikely(swp_type(entry) == SWP_MIGRATION_READ ||
184 swp_type(entry) == SWP_MIGRATION_WRITE);
187 static inline int is_write_migration_entry(swp_entry_t entry)
189 return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE);
192 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
194 return swp_offset(entry);
197 static inline struct page *migration_entry_to_page(swp_entry_t entry)
199 struct page *p = pfn_to_page(swp_offset(entry));
201 * Any use of migration entries may only occur while the
202 * corresponding page is locked
204 BUG_ON(!PageLocked(compound_head(p)));
208 static inline void make_migration_entry_read(swp_entry_t *entry)
210 *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry));
213 extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
215 extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
216 unsigned long address);
217 extern void migration_entry_wait_huge(struct vm_area_struct *vma,
218 struct mm_struct *mm, pte_t *pte);
221 #define make_migration_entry(page, write) swp_entry(0, 0)
222 static inline int is_migration_entry(swp_entry_t swp)
227 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
232 static inline struct page *migration_entry_to_page(swp_entry_t entry)
237 static inline void make_migration_entry_read(swp_entry_t *entryp) { }
238 static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
240 static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
241 unsigned long address) { }
242 static inline void migration_entry_wait_huge(struct vm_area_struct *vma,
243 struct mm_struct *mm, pte_t *pte) { }
244 static inline int is_write_migration_entry(swp_entry_t entry)
251 struct page_vma_mapped_walk;
253 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
254 extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
257 extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
260 extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd);
262 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
264 swp_entry_t arch_entry;
266 if (pmd_swp_soft_dirty(pmd))
267 pmd = pmd_swp_clear_soft_dirty(pmd);
268 if (pmd_swp_uffd_wp(pmd))
269 pmd = pmd_swp_clear_uffd_wp(pmd);
270 arch_entry = __pmd_to_swp_entry(pmd);
271 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
274 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
276 swp_entry_t arch_entry;
278 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
279 return __swp_entry_to_pmd(arch_entry);
282 static inline int is_pmd_migration_entry(pmd_t pmd)
284 return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
287 static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
293 static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
299 static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { }
301 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
303 return swp_entry(0, 0);
306 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
311 static inline int is_pmd_migration_entry(pmd_t pmd)
317 #ifdef CONFIG_MEMORY_FAILURE
319 extern atomic_long_t num_poisoned_pages __read_mostly;
322 * Support for hardware poisoned pages
324 static inline swp_entry_t make_hwpoison_entry(struct page *page)
326 BUG_ON(!PageLocked(page));
327 return swp_entry(SWP_HWPOISON, page_to_pfn(page));
330 static inline int is_hwpoison_entry(swp_entry_t entry)
332 return swp_type(entry) == SWP_HWPOISON;
335 static inline void num_poisoned_pages_inc(void)
337 atomic_long_inc(&num_poisoned_pages);
340 static inline void num_poisoned_pages_dec(void)
342 atomic_long_dec(&num_poisoned_pages);
347 static inline swp_entry_t make_hwpoison_entry(struct page *page)
349 return swp_entry(0, 0);
352 static inline int is_hwpoison_entry(swp_entry_t swp)
357 static inline void num_poisoned_pages_inc(void)
362 #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) || \
363 defined(CONFIG_DEVICE_PRIVATE)
364 static inline int non_swap_entry(swp_entry_t entry)
366 return swp_type(entry) >= MAX_SWAPFILES;
369 static inline int non_swap_entry(swp_entry_t entry)
375 #endif /* CONFIG_MMU */
376 #endif /* _LINUX_SWAPOPS_H */