1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_SWAPOPS_H
3 #define _LINUX_SWAPOPS_H
5 #include <linux/radix-tree.h>
9 * swapcache pages are stored in the swapper_space radix tree. We want to
10 * get good packing density in that tree, so the index should be dense in
13 * We arrange the `type' and `offset' fields so that `type' is at the seven
14 * high-order bits of the swp_entry_t and `offset' is right-aligned in the
15 * remaining bits. Although `type' itself needs only five bits, we allow for
16 * shmem/tmpfs to shift it all up a further two bits: see swp_to_radix_entry().
18 * swp_entry_t's are *never* stored anywhere in their arch-dependent format.
20 #define SWP_TYPE_SHIFT(e) ((sizeof(e.val) * 8) - \
21 (MAX_SWAPFILES_SHIFT + RADIX_TREE_EXCEPTIONAL_SHIFT))
22 #define SWP_OFFSET_MASK(e) ((1UL << SWP_TYPE_SHIFT(e)) - 1)
25 * Store a type+offset into a swp_entry_t in an arch-independent format
27 static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset)
31 ret.val = (type << SWP_TYPE_SHIFT(ret)) |
32 (offset & SWP_OFFSET_MASK(ret));
37 * Extract the `type' field from a swp_entry_t. The swp_entry_t is in
38 * arch-independent format
40 static inline unsigned swp_type(swp_entry_t entry)
42 return (entry.val >> SWP_TYPE_SHIFT(entry));
46 * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in
47 * arch-independent format
49 static inline pgoff_t swp_offset(swp_entry_t entry)
51 return entry.val & SWP_OFFSET_MASK(entry);
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);
63 * Convert the arch-dependent pte representation of a swp_entry_t into an
64 * arch-independent swp_entry_t.
66 static inline swp_entry_t pte_to_swp_entry(pte_t pte)
68 swp_entry_t arch_entry;
70 if (pte_swp_soft_dirty(pte))
71 pte = pte_swp_clear_soft_dirty(pte);
72 arch_entry = __pte_to_swp_entry(pte);
73 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
77 * Convert the arch-independent representation of a swp_entry_t into the
78 * arch-dependent pte representation.
80 static inline pte_t swp_entry_to_pte(swp_entry_t entry)
82 swp_entry_t arch_entry;
84 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
85 return __swp_entry_to_pte(arch_entry);
88 static inline swp_entry_t radix_to_swp_entry(void *arg)
92 entry.val = (unsigned long)arg >> RADIX_TREE_EXCEPTIONAL_SHIFT;
96 static inline void *swp_to_radix_entry(swp_entry_t entry)
100 value = entry.val << RADIX_TREE_EXCEPTIONAL_SHIFT;
101 return (void *)(value | RADIX_TREE_EXCEPTIONAL_ENTRY);
104 #if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
105 static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
107 return swp_entry(write ? SWP_DEVICE_WRITE : SWP_DEVICE_READ,
111 static inline bool is_device_private_entry(swp_entry_t entry)
113 int type = swp_type(entry);
114 return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE;
117 static inline void make_device_private_entry_read(swp_entry_t *entry)
119 *entry = swp_entry(SWP_DEVICE_READ, swp_offset(*entry));
122 static inline bool is_write_device_private_entry(swp_entry_t entry)
124 return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
127 static inline struct page *device_private_entry_to_page(swp_entry_t entry)
129 return pfn_to_page(swp_offset(entry));
132 int device_private_entry_fault(struct vm_area_struct *vma,
137 #else /* CONFIG_DEVICE_PRIVATE */
138 static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
140 return swp_entry(0, 0);
143 static inline void make_device_private_entry_read(swp_entry_t *entry)
147 static inline bool is_device_private_entry(swp_entry_t entry)
152 static inline bool is_write_device_private_entry(swp_entry_t entry)
157 static inline struct page *device_private_entry_to_page(swp_entry_t entry)
162 static inline int device_private_entry_fault(struct vm_area_struct *vma,
168 return VM_FAULT_SIGBUS;
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 struct page *migration_entry_to_page(swp_entry_t entry)
194 struct page *p = pfn_to_page(swp_offset(entry));
196 * Any use of migration entries may only occur while the
197 * corresponding page is locked
199 BUG_ON(!PageLocked(compound_head(p)));
203 static inline void make_migration_entry_read(swp_entry_t *entry)
205 *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry));
208 extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
210 extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
211 unsigned long address);
212 extern void migration_entry_wait_huge(struct vm_area_struct *vma,
213 struct mm_struct *mm, pte_t *pte);
216 #define make_migration_entry(page, write) swp_entry(0, 0)
217 static inline int is_migration_entry(swp_entry_t swp)
221 static inline struct page *migration_entry_to_page(swp_entry_t entry)
226 static inline void make_migration_entry_read(swp_entry_t *entryp) { }
227 static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
229 static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
230 unsigned long address) { }
231 static inline void migration_entry_wait_huge(struct vm_area_struct *vma,
232 struct mm_struct *mm, pte_t *pte) { }
233 static inline int is_write_migration_entry(swp_entry_t entry)
240 struct page_vma_mapped_walk;
242 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
243 extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
246 extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
249 extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd);
251 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
253 swp_entry_t arch_entry;
255 if (pmd_swp_soft_dirty(pmd))
256 pmd = pmd_swp_clear_soft_dirty(pmd);
257 arch_entry = __pmd_to_swp_entry(pmd);
258 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
261 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
263 swp_entry_t arch_entry;
265 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
266 return __swp_entry_to_pmd(arch_entry);
269 static inline int is_pmd_migration_entry(pmd_t pmd)
271 return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
274 static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
280 static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
286 static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { }
288 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
290 return swp_entry(0, 0);
293 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
298 static inline int is_pmd_migration_entry(pmd_t pmd)
304 #ifdef CONFIG_MEMORY_FAILURE
306 extern atomic_long_t num_poisoned_pages __read_mostly;
309 * Support for hardware poisoned pages
311 static inline swp_entry_t make_hwpoison_entry(struct page *page)
313 BUG_ON(!PageLocked(page));
314 return swp_entry(SWP_HWPOISON, page_to_pfn(page));
317 static inline int is_hwpoison_entry(swp_entry_t entry)
319 return swp_type(entry) == SWP_HWPOISON;
322 static inline bool test_set_page_hwpoison(struct page *page)
324 return TestSetPageHWPoison(page);
327 static inline void num_poisoned_pages_inc(void)
329 atomic_long_inc(&num_poisoned_pages);
332 static inline void num_poisoned_pages_dec(void)
334 atomic_long_dec(&num_poisoned_pages);
339 static inline swp_entry_t make_hwpoison_entry(struct page *page)
341 return swp_entry(0, 0);
344 static inline int is_hwpoison_entry(swp_entry_t swp)
349 static inline bool test_set_page_hwpoison(struct page *page)
354 static inline void num_poisoned_pages_inc(void)
359 #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION)
360 static inline int non_swap_entry(swp_entry_t entry)
362 return swp_type(entry) >= MAX_SWAPFILES;
365 static inline int non_swap_entry(swp_entry_t entry)
371 #endif /* _LINUX_SWAPOPS_H */