1 #ifndef _LINUX_SWAPOPS_H
2 #define _LINUX_SWAPOPS_H
4 #include <linux/radix-tree.h>
8 * swapcache pages are stored in the swapper_space radix tree. We want to
9 * get good packing density in that tree, so the index should be dense in
12 * We arrange the `type' and `offset' fields so that `type' is at the five
13 * high-order bits of the swp_entry_t and `offset' is right-aligned in the
16 * swp_entry_t's are *never* stored anywhere in their arch-dependent format.
18 #define SWP_TYPE_SHIFT(e) (sizeof(e.val) * 8 - MAX_SWAPFILES_SHIFT)
19 #define SWP_OFFSET_MASK(e) ((1UL << SWP_TYPE_SHIFT(e)) - 1)
22 * Store a type+offset into a swp_entry_t in an arch-independent format
24 static inline swp_entry_t
swp_entry(unsigned long type
, pgoff_t offset
)
28 ret
.val
= (type
<< SWP_TYPE_SHIFT(ret
)) |
29 (offset
& SWP_OFFSET_MASK(ret
));
34 * Extract the `type' field from a swp_entry_t. The swp_entry_t is in
35 * arch-independent format
37 static inline unsigned swp_type(swp_entry_t entry
)
39 return (entry
.val
>> SWP_TYPE_SHIFT(entry
));
43 * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in
44 * arch-independent format
46 static inline pgoff_t
swp_offset(swp_entry_t entry
)
48 return entry
.val
& SWP_OFFSET_MASK(entry
);
52 /* check whether a pte points to a swap entry */
53 static inline int is_swap_pte(pte_t pte
)
55 return !pte_none(pte
) && !pte_present(pte
) && !pte_file(pte
);
60 * Convert the arch-dependent pte representation of a swp_entry_t into an
61 * arch-independent swp_entry_t.
63 static inline swp_entry_t
pte_to_swp_entry(pte_t pte
)
65 swp_entry_t arch_entry
;
67 BUG_ON(pte_file(pte
));
68 arch_entry
= __pte_to_swp_entry(pte
);
69 return swp_entry(__swp_type(arch_entry
), __swp_offset(arch_entry
));
73 * Convert the arch-independent representation of a swp_entry_t into the
74 * arch-dependent pte representation.
76 static inline pte_t
swp_entry_to_pte(swp_entry_t entry
)
78 swp_entry_t arch_entry
;
80 arch_entry
= __swp_entry(swp_type(entry
), swp_offset(entry
));
81 BUG_ON(pte_file(__swp_entry_to_pte(arch_entry
)));
82 return __swp_entry_to_pte(arch_entry
);
85 static inline swp_entry_t
radix_to_swp_entry(void *arg
)
89 entry
.val
= (unsigned long)arg
>> RADIX_TREE_EXCEPTIONAL_SHIFT
;
93 static inline void *swp_to_radix_entry(swp_entry_t entry
)
97 value
= entry
.val
<< RADIX_TREE_EXCEPTIONAL_SHIFT
;
98 return (void *)(value
| RADIX_TREE_EXCEPTIONAL_ENTRY
);
101 #ifdef CONFIG_MIGRATION
102 static inline swp_entry_t
make_migration_entry(struct page
*page
, int write
)
104 BUG_ON(!PageLocked(page
));
105 return swp_entry(write
? SWP_MIGRATION_WRITE
: SWP_MIGRATION_READ
,
109 static inline int is_migration_entry(swp_entry_t entry
)
111 return unlikely(swp_type(entry
) == SWP_MIGRATION_READ
||
112 swp_type(entry
) == SWP_MIGRATION_WRITE
);
115 static inline int is_write_migration_entry(swp_entry_t entry
)
117 return unlikely(swp_type(entry
) == SWP_MIGRATION_WRITE
);
120 static inline struct page
*migration_entry_to_page(swp_entry_t entry
)
122 struct page
*p
= pfn_to_page(swp_offset(entry
));
124 * Any use of migration entries may only occur while the
125 * corresponding page is locked
127 BUG_ON(!PageLocked(p
));
131 static inline void make_migration_entry_read(swp_entry_t
*entry
)
133 *entry
= swp_entry(SWP_MIGRATION_READ
, swp_offset(*entry
));
136 extern void migration_entry_wait(struct mm_struct
*mm
, pmd_t
*pmd
,
137 unsigned long address
);
140 #define make_migration_entry(page, write) swp_entry(0, 0)
141 static inline int is_migration_entry(swp_entry_t swp
)
145 #define migration_entry_to_page(swp) NULL
146 static inline void make_migration_entry_read(swp_entry_t
*entryp
) { }
147 static inline void migration_entry_wait(struct mm_struct
*mm
, pmd_t
*pmd
,
148 unsigned long address
) { }
149 static inline int is_write_migration_entry(swp_entry_t entry
)
156 #ifdef CONFIG_MEMORY_FAILURE
158 * Support for hardware poisoned pages
160 static inline swp_entry_t
make_hwpoison_entry(struct page
*page
)
162 BUG_ON(!PageLocked(page
));
163 return swp_entry(SWP_HWPOISON
, page_to_pfn(page
));
166 static inline int is_hwpoison_entry(swp_entry_t entry
)
168 return swp_type(entry
) == SWP_HWPOISON
;
172 static inline swp_entry_t
make_hwpoison_entry(struct page
*page
)
174 return swp_entry(0, 0);
177 static inline int is_hwpoison_entry(swp_entry_t swp
)
183 #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION)
184 static inline int non_swap_entry(swp_entry_t entry
)
186 return swp_type(entry
) >= MAX_SWAPFILES
;
189 static inline int non_swap_entry(swp_entry_t entry
)
195 #endif /* _LINUX_SWAPOPS_H */