root/include/linux/swapops.h

INCLUDED FROM

DEFINITIONS

1. swp_type
2. swp_offset
3. is_swap_pte
4. pte_to_swp_entry
5. swp_entry_to_pte
6. radix_to_swp_entry
7. swp_to_radix_entry
8. make_device_private_entry
9. is_device_private_entry
10. make_device_private_entry_read
11. is_write_device_private_entry
12. device_private_entry_to_pfn
13. device_private_entry_to_page
14. make_device_private_entry
15. make_device_private_entry_read
16. is_device_private_entry
17. is_write_device_private_entry
18. device_private_entry_to_pfn
19. device_private_entry_to_page
20. make_migration_entry
21. is_migration_entry
22. is_write_migration_entry
23. migration_entry_to_pfn
24. migration_entry_to_page
25. make_migration_entry_read
26. is_migration_entry
27. migration_entry_to_pfn
28. migration_entry_to_page
29. make_migration_entry_read
30. __migration_entry_wait
31. migration_entry_wait
32. migration_entry_wait_huge
33. is_write_migration_entry
34. pmd_to_swp_entry
35. swp_entry_to_pmd
36. is_pmd_migration_entry
37. set_pmd_migration_entry
38. remove_migration_pmd
39. pmd_migration_entry_wait
40. pmd_to_swp_entry
41. swp_entry_to_pmd
42. is_pmd_migration_entry
43. make_hwpoison_entry
44. is_hwpoison_entry
45. num_poisoned_pages_inc
46. num_poisoned_pages_dec
47. make_hwpoison_entry
48. is_hwpoison_entry
49. num_poisoned_pages_inc
50. non_swap_entry
51. non_swap_entry

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_SWAPOPS_H
   3 #define _LINUX_SWAPOPS_H
   4 
   5 #include <linux/radix-tree.h>
   6 #include <linux/bug.h>
   7 #include <linux/mm_types.h>
   8 
   9 #ifdef CONFIG_MMU
  10 
  11 /*
  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
  14  * the low-order bits.
  15  *
  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().
  20  *
  21  * swp_entry_t's are *never* stored anywhere in their arch-dependent format.
  22  */
  23 #define SWP_TYPE_SHIFT  (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
  24 #define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1)
  25 
  26 /*
  27  * Store a type+offset into a swp_entry_t in an arch-independent format
  28  */
  29 static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset)
  30 {
  31         swp_entry_t ret;
  32 
  33         ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK);
  34         return ret;
  35 }
  36 
  37 /*
  38  * Extract the `type' field from a swp_entry_t.  The swp_entry_t is in
  39  * arch-independent format
  40  */
  41 static inline unsigned swp_type(swp_entry_t entry)
  42 {
  43         return (entry.val >> SWP_TYPE_SHIFT);
  44 }
  45 
  46 /*
  47  * Extract the `offset' field from a swp_entry_t.  The swp_entry_t is in
  48  * arch-independent format
  49  */
  50 static inline pgoff_t swp_offset(swp_entry_t entry)
  51 {
  52         return entry.val & SWP_OFFSET_MASK;
  53 }
  54 
  55 /* check whether a pte points to a swap entry */
  56 static inline int is_swap_pte(pte_t pte)
  57 {
  58         return !pte_none(pte) && !pte_present(pte);
  59 }
  60 
  61 /*
  62  * Convert the arch-dependent pte representation of a swp_entry_t into an
  63  * arch-independent swp_entry_t.
  64  */
  65 static inline swp_entry_t pte_to_swp_entry(pte_t pte)
  66 {
  67         swp_entry_t arch_entry;
  68 
  69         if (pte_swp_soft_dirty(pte))
  70                 pte = pte_swp_clear_soft_dirty(pte);
  71         arch_entry = __pte_to_swp_entry(pte);
  72         return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
  73 }
  74 
  75 /*
  76  * Convert the arch-independent representation of a swp_entry_t into the
  77  * arch-dependent pte representation.
  78  */
  79 static inline pte_t swp_entry_to_pte(swp_entry_t entry)
  80 {
  81         swp_entry_t arch_entry;
  82 
  83         arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
  84         return __swp_entry_to_pte(arch_entry);
  85 }
  86 
  87 static inline swp_entry_t radix_to_swp_entry(void *arg)
  88 {
  89         swp_entry_t entry;
  90 
  91         entry.val = xa_to_value(arg);
  92         return entry;
  93 }
  94 
  95 static inline void *swp_to_radix_entry(swp_entry_t entry)
  96 {
  97         return xa_mk_value(entry.val);
  98 }
  99 
 100 #if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
 101 static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
 102 {
 103         return swp_entry(write ? SWP_DEVICE_WRITE : SWP_DEVICE_READ,
 104                          page_to_pfn(page));
 105 }
 106 
 107 static inline bool is_device_private_entry(swp_entry_t entry)
 108 {
 109         int type = swp_type(entry);
 110         return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE;
 111 }
 112 
 113 static inline void make_device_private_entry_read(swp_entry_t *entry)
 114 {
 115         *entry = swp_entry(SWP_DEVICE_READ, swp_offset(*entry));
 116 }
 117 
 118 static inline bool is_write_device_private_entry(swp_entry_t entry)
 119 {
 120         return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
 121 }
 122 
 123 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
 124 {
 125         return swp_offset(entry);
 126 }
 127 
 128 static inline struct page *device_private_entry_to_page(swp_entry_t entry)
 129 {
 130         return pfn_to_page(swp_offset(entry));
 131 }
 132 #else /* CONFIG_DEVICE_PRIVATE */
 133 static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
 134 {
 135         return swp_entry(0, 0);
 136 }
 137 
 138 static inline void make_device_private_entry_read(swp_entry_t *entry)
 139 {
 140 }
 141 
 142 static inline bool is_device_private_entry(swp_entry_t entry)
 143 {
 144         return false;
 145 }
 146 
 147 static inline bool is_write_device_private_entry(swp_entry_t entry)
 148 {
 149         return false;
 150 }
 151 
 152 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
 153 {
 154         return 0;
 155 }
 156 
 157 static inline struct page *device_private_entry_to_page(swp_entry_t entry)
 158 {
 159         return NULL;
 160 }
 161 #endif /* CONFIG_DEVICE_PRIVATE */
 162 
 163 #ifdef CONFIG_MIGRATION
 164 static inline swp_entry_t make_migration_entry(struct page *page, int write)
 165 {
 166         BUG_ON(!PageLocked(compound_head(page)));
 167 
 168         return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ,
 169                         page_to_pfn(page));
 170 }
 171 
 172 static inline int is_migration_entry(swp_entry_t entry)
 173 {
 174         return unlikely(swp_type(entry) == SWP_MIGRATION_READ ||
 175                         swp_type(entry) == SWP_MIGRATION_WRITE);
 176 }
 177 
 178 static inline int is_write_migration_entry(swp_entry_t entry)
 179 {
 180         return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE);
 181 }
 182 
 183 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
 184 {
 185         return swp_offset(entry);
 186 }
 187 
 188 static inline struct page *migration_entry_to_page(swp_entry_t entry)
 189 {
 190         struct page *p = pfn_to_page(swp_offset(entry));
 191         /*
 192          * Any use of migration entries may only occur while the
 193          * corresponding page is locked
 194          */
 195         BUG_ON(!PageLocked(compound_head(p)));
 196         return p;
 197 }
 198 
 199 static inline void make_migration_entry_read(swp_entry_t *entry)
 200 {
 201         *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry));
 202 }
 203 
 204 extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
 205                                         spinlock_t *ptl);
 206 extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
 207                                         unsigned long address);
 208 extern void migration_entry_wait_huge(struct vm_area_struct *vma,
 209                 struct mm_struct *mm, pte_t *pte);
 210 #else
 211 
 212 #define make_migration_entry(page, write) swp_entry(0, 0)
 213 static inline int is_migration_entry(swp_entry_t swp)
 214 {
 215         return 0;
 216 }
 217 
 218 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
 219 {
 220         return 0;
 221 }
 222 
 223 static inline struct page *migration_entry_to_page(swp_entry_t entry)
 224 {
 225         return NULL;
 226 }
 227 
 228 static inline void make_migration_entry_read(swp_entry_t *entryp) { }
 229 static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
 230                                         spinlock_t *ptl) { }
 231 static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
 232                                          unsigned long address) { }
 233 static inline void migration_entry_wait_huge(struct vm_area_struct *vma,
 234                 struct mm_struct *mm, pte_t *pte) { }
 235 static inline int is_write_migration_entry(swp_entry_t entry)
 236 {
 237         return 0;
 238 }
 239 
 240 #endif
 241 
 242 struct page_vma_mapped_walk;
 243 
 244 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
 245 extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
 246                 struct page *page);
 247 
 248 extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
 249                 struct page *new);
 250 
 251 extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd);
 252 
 253 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
 254 {
 255         swp_entry_t arch_entry;
 256 
 257         if (pmd_swp_soft_dirty(pmd))
 258                 pmd = pmd_swp_clear_soft_dirty(pmd);
 259         arch_entry = __pmd_to_swp_entry(pmd);
 260         return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
 261 }
 262 
 263 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
 264 {
 265         swp_entry_t arch_entry;
 266 
 267         arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
 268         return __swp_entry_to_pmd(arch_entry);
 269 }
 270 
 271 static inline int is_pmd_migration_entry(pmd_t pmd)
 272 {
 273         return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
 274 }
 275 #else
 276 static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
 277                 struct page *page)
 278 {
 279         BUILD_BUG();
 280 }
 281 
 282 static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
 283                 struct page *new)
 284 {
 285         BUILD_BUG();
 286 }
 287 
 288 static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { }
 289 
 290 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
 291 {
 292         return swp_entry(0, 0);
 293 }
 294 
 295 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
 296 {
 297         return __pmd(0);
 298 }
 299 
 300 static inline int is_pmd_migration_entry(pmd_t pmd)
 301 {
 302         return 0;
 303 }
 304 #endif
 305 
 306 #ifdef CONFIG_MEMORY_FAILURE
 307 
 308 extern atomic_long_t num_poisoned_pages __read_mostly;
 309 
 310 /*
 311  * Support for hardware poisoned pages
 312  */
 313 static inline swp_entry_t make_hwpoison_entry(struct page *page)
 314 {
 315         BUG_ON(!PageLocked(page));
 316         return swp_entry(SWP_HWPOISON, page_to_pfn(page));
 317 }
 318 
 319 static inline int is_hwpoison_entry(swp_entry_t entry)
 320 {
 321         return swp_type(entry) == SWP_HWPOISON;
 322 }
 323 
 324 static inline void num_poisoned_pages_inc(void)
 325 {
 326         atomic_long_inc(&num_poisoned_pages);
 327 }
 328 
 329 static inline void num_poisoned_pages_dec(void)
 330 {
 331         atomic_long_dec(&num_poisoned_pages);
 332 }
 333 
 334 #else
 335 
 336 static inline swp_entry_t make_hwpoison_entry(struct page *page)
 337 {
 338         return swp_entry(0, 0);
 339 }
 340 
 341 static inline int is_hwpoison_entry(swp_entry_t swp)
 342 {
 343         return 0;
 344 }
 345 
 346 static inline void num_poisoned_pages_inc(void)
 347 {
 348 }
 349 #endif
 350 
 351 #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) || \
 352     defined(CONFIG_DEVICE_PRIVATE)
 353 static inline int non_swap_entry(swp_entry_t entry)
 354 {
 355         return swp_type(entry) >= MAX_SWAPFILES;
 356 }
 357 #else
 358 static inline int non_swap_entry(swp_entry_t entry)
 359 {
 360         return 0;
 361 }
 362 #endif
 363 
 364 #endif /* CONFIG_MMU */
 365 #endif /* _LINUX_SWAPOPS_H */