include/linux/swapops.h

   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 /*
  10  * swapcache pages are stored in the swapper_space radix tree.  We want to
  11  * get good packing density in that tree, so the index should be dense in
  12  * the low-order bits.
  13  *
  14  * We arrange the `type' and `offset' fields so that `type' is at the seven
  15  * high-order bits of the swp_entry_t and `offset' is right-aligned in the
  16  * remaining bits.  Although `type' itself needs only five bits, we allow for
  17  * shmem/tmpfs to shift it all up a further two bits: see swp_to_radix_entry().
  18  *
  19  * swp_entry_t's are *never* stored anywhere in their arch-dependent format.
  20  */
  21 #define SWP_TYPE_SHIFT  (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
  22 #define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1)
  23
  24 /*
  25  * Store a type+offset into a swp_entry_t in an arch-independent format
  26  */
  27 static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset)
  28 {
  29         swp_entry_t ret;
  30
  31         ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK);
  32         return ret;
  33 }
  34
  35 /*
  36  * Extract the `type' field from a swp_entry_t.  The swp_entry_t is in
  37  * arch-independent format
  38  */
  39 static inline unsigned swp_type(swp_entry_t entry)
  40 {
  41         return (entry.val >> SWP_TYPE_SHIFT);
  42 }
  43
  44 /*
  45  * Extract the `offset' field from a swp_entry_t.  The swp_entry_t is in
  46  * arch-independent format
  47  */
  48 static inline pgoff_t swp_offset(swp_entry_t entry)
  49 {
  50         return entry.val & SWP_OFFSET_MASK;
  51 }
  52
  53 #ifdef CONFIG_MMU
  54 /* check whether a pte points to a swap entry */
  55 static inline int is_swap_pte(pte_t pte)
  56 {
  57         return !pte_none(pte) && !pte_present(pte);
  58 }
  59 #endif
  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
 133 vm_fault_t device_private_entry_fault(struct vm_area_struct *vma,
 134                        unsigned long addr,
 135                        swp_entry_t entry,
 136                        unsigned int flags,
 137                        pmd_t *pmdp);
 138 #else /* CONFIG_DEVICE_PRIVATE */
 139 static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
 140 {
 141         return swp_entry(0, 0);
 142 }
 143
 144 static inline void make_device_private_entry_read(swp_entry_t *entry)
 145 {
 146 }
 147
 148 static inline bool is_device_private_entry(swp_entry_t entry)
 149 {
 150         return false;
 151 }
 152
 153 static inline bool is_write_device_private_entry(swp_entry_t entry)
 154 {
 155         return false;
 156 }
 157
 158 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
 159 {
 160         return 0;
 161 }
 162
 163 static inline struct page *device_private_entry_to_page(swp_entry_t entry)
 164 {
 165         return NULL;
 166 }
 167
 168 static inline vm_fault_t device_private_entry_fault(struct vm_area_struct *vma,
 169                                      unsigned long addr,
 170                                      swp_entry_t entry,
 171                                      unsigned int flags,
 172                                      pmd_t *pmdp)
 173 {
 174         return VM_FAULT_SIGBUS;
 175 }
 176 #endif /* CONFIG_DEVICE_PRIVATE */
 177
 178 #ifdef CONFIG_MIGRATION
 179 static inline swp_entry_t make_migration_entry(struct page *page, int write)
 180 {
 181         BUG_ON(!PageLocked(compound_head(page)));
 182
 183         return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ,
 184                         page_to_pfn(page));
 185 }
 186
 187 static inline int is_migration_entry(swp_entry_t entry)
 188 {
 189         return unlikely(swp_type(entry) == SWP_MIGRATION_READ ||
 190                         swp_type(entry) == SWP_MIGRATION_WRITE);
 191 }
 192
 193 static inline int is_write_migration_entry(swp_entry_t entry)
 194 {
 195         return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE);
 196 }
 197
 198 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
 199 {
 200         return swp_offset(entry);
 201 }
 202
 203 static inline struct page *migration_entry_to_page(swp_entry_t entry)
 204 {
 205         struct page *p = pfn_to_page(swp_offset(entry));
 206         /*
 207          * Any use of migration entries may only occur while the
 208          * corresponding page is locked
 209          */
 210         BUG_ON(!PageLocked(compound_head(p)));
 211         return p;
 212 }
 213
 214 static inline void make_migration_entry_read(swp_entry_t *entry)
 215 {
 216         *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry));
 217 }
 218
 219 extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
 220                                         spinlock_t *ptl);
 221 extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
 222                                         unsigned long address);
 223 extern void migration_entry_wait_huge(struct vm_area_struct *vma,
 224                 struct mm_struct *mm, pte_t *pte);
 225 #else
 226
 227 #define make_migration_entry(page, write) swp_entry(0, 0)
 228 static inline int is_migration_entry(swp_entry_t swp)
 229 {
 230         return 0;
 231 }
 232
 233 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
 234 {
 235         return 0;
 236 }
 237
 238 static inline struct page *migration_entry_to_page(swp_entry_t entry)
 239 {
 240         return NULL;
 241 }
 242
 243 static inline void make_migration_entry_read(swp_entry_t *entryp) { }
 244 static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
 245                                         spinlock_t *ptl) { }
 246 static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
 247                                          unsigned long address) { }
 248 static inline void migration_entry_wait_huge(struct vm_area_struct *vma,
 249                 struct mm_struct *mm, pte_t *pte) { }
 250 static inline int is_write_migration_entry(swp_entry_t entry)
 251 {
 252         return 0;
 253 }
 254
 255 #endif
 256
 257 struct page_vma_mapped_walk;
 258
 259 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
 260 extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
 261                 struct page *page);
 262
 263 extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
 264                 struct page *new);
 265
 266 extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd);
 267
 268 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
 269 {
 270         swp_entry_t arch_entry;
 271
 272         if (pmd_swp_soft_dirty(pmd))
 273                 pmd = pmd_swp_clear_soft_dirty(pmd);
 274         arch_entry = __pmd_to_swp_entry(pmd);
 275         return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
 276 }
 277
 278 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
 279 {
 280         swp_entry_t arch_entry;
 281
 282         arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
 283         return __swp_entry_to_pmd(arch_entry);
 284 }
 285
 286 static inline int is_pmd_migration_entry(pmd_t pmd)
 287 {
 288         return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
 289 }
 290 #else
 291 static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
 292                 struct page *page)
 293 {
 294         BUILD_BUG();
 295 }
 296
 297 static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
 298                 struct page *new)
 299 {
 300         BUILD_BUG();
 301 }
 302
 303 static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { }
 304
 305 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
 306 {
 307         return swp_entry(0, 0);
 308 }
 309
 310 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
 311 {
 312         return __pmd(0);
 313 }
 314
 315 static inline int is_pmd_migration_entry(pmd_t pmd)
 316 {
 317         return 0;
 318 }
 319 #endif
 320
 321 #ifdef CONFIG_MEMORY_FAILURE
 322
 323 extern atomic_long_t num_poisoned_pages __read_mostly;
 324
 325 /*
 326  * Support for hardware poisoned pages
 327  */
 328 static inline swp_entry_t make_hwpoison_entry(struct page *page)
 329 {
 330         BUG_ON(!PageLocked(page));
 331         return swp_entry(SWP_HWPOISON, page_to_pfn(page));
 332 }
 333
 334 static inline int is_hwpoison_entry(swp_entry_t entry)
 335 {
 336         return swp_type(entry) == SWP_HWPOISON;
 337 }
 338
 339 static inline void num_poisoned_pages_inc(void)
 340 {
 341         atomic_long_inc(&num_poisoned_pages);
 342 }
 343
 344 static inline void num_poisoned_pages_dec(void)
 345 {
 346         atomic_long_dec(&num_poisoned_pages);
 347 }
 348
 349 #else
 350
 351 static inline swp_entry_t make_hwpoison_entry(struct page *page)
 352 {
 353         return swp_entry(0, 0);
 354 }
 355
 356 static inline int is_hwpoison_entry(swp_entry_t swp)
 357 {
 358         return 0;
 359 }
 360
 361 static inline void num_poisoned_pages_inc(void)
 362 {
 363 }
 364 #endif
 365
 366 #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION)
 367 static inline int non_swap_entry(swp_entry_t entry)
 368 {
 369         return swp_type(entry) >= MAX_SWAPFILES;
 370 }
 371 #else
 372 static inline int non_swap_entry(swp_entry_t entry)
 373 {
 374         return 0;
 375 }
 376 #endif
 377
 378 #endif /* _LINUX_SWAPOPS_H */