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a2c16d6c HD |
1 | #ifndef _LINUX_SWAPOPS_H |
2 | #define _LINUX_SWAPOPS_H | |
3 | ||
4 | #include <linux/radix-tree.h> | |
187f1882 | 5 | #include <linux/bug.h> |
a2c16d6c | 6 | |
1da177e4 LT |
7 | /* |
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 | |
10 | * the low-order bits. | |
11 | * | |
12 | * We arrange the `type' and `offset' fields so that `type' is at the five | |
e83a9596 | 13 | * high-order bits of the swp_entry_t and `offset' is right-aligned in the |
1da177e4 LT |
14 | * remaining bits. |
15 | * | |
16 | * swp_entry_t's are *never* stored anywhere in their arch-dependent format. | |
17 | */ | |
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) | |
20 | ||
21 | /* | |
22 | * Store a type+offset into a swp_entry_t in an arch-independent format | |
23 | */ | |
24 | static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset) | |
25 | { | |
26 | swp_entry_t ret; | |
27 | ||
28 | ret.val = (type << SWP_TYPE_SHIFT(ret)) | | |
29 | (offset & SWP_OFFSET_MASK(ret)); | |
30 | return ret; | |
31 | } | |
32 | ||
33 | /* | |
34 | * Extract the `type' field from a swp_entry_t. The swp_entry_t is in | |
35 | * arch-independent format | |
36 | */ | |
37 | static inline unsigned swp_type(swp_entry_t entry) | |
38 | { | |
39 | return (entry.val >> SWP_TYPE_SHIFT(entry)); | |
40 | } | |
41 | ||
42 | /* | |
43 | * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in | |
44 | * arch-independent format | |
45 | */ | |
46 | static inline pgoff_t swp_offset(swp_entry_t entry) | |
47 | { | |
48 | return entry.val & SWP_OFFSET_MASK(entry); | |
49 | } | |
50 | ||
880cdf3a | 51 | #ifdef CONFIG_MMU |
698dd4ba MM |
52 | /* check whether a pte points to a swap entry */ |
53 | static inline int is_swap_pte(pte_t pte) | |
54 | { | |
55 | return !pte_none(pte) && !pte_present(pte) && !pte_file(pte); | |
56 | } | |
880cdf3a | 57 | #endif |
698dd4ba | 58 | |
1da177e4 LT |
59 | /* |
60 | * Convert the arch-dependent pte representation of a swp_entry_t into an | |
61 | * arch-independent swp_entry_t. | |
62 | */ | |
63 | static inline swp_entry_t pte_to_swp_entry(pte_t pte) | |
64 | { | |
65 | swp_entry_t arch_entry; | |
66 | ||
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)); | |
70 | } | |
71 | ||
72 | /* | |
73 | * Convert the arch-independent representation of a swp_entry_t into the | |
74 | * arch-dependent pte representation. | |
75 | */ | |
76 | static inline pte_t swp_entry_to_pte(swp_entry_t entry) | |
77 | { | |
78 | swp_entry_t arch_entry; | |
79 | ||
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); | |
83 | } | |
0697212a | 84 | |
a2c16d6c HD |
85 | static inline swp_entry_t radix_to_swp_entry(void *arg) |
86 | { | |
87 | swp_entry_t entry; | |
88 | ||
89 | entry.val = (unsigned long)arg >> RADIX_TREE_EXCEPTIONAL_SHIFT; | |
90 | return entry; | |
91 | } | |
92 | ||
93 | static inline void *swp_to_radix_entry(swp_entry_t entry) | |
94 | { | |
95 | unsigned long value; | |
96 | ||
97 | value = entry.val << RADIX_TREE_EXCEPTIONAL_SHIFT; | |
98 | return (void *)(value | RADIX_TREE_EXCEPTIONAL_ENTRY); | |
99 | } | |
100 | ||
0697212a CL |
101 | #ifdef CONFIG_MIGRATION |
102 | static inline swp_entry_t make_migration_entry(struct page *page, int write) | |
103 | { | |
104 | BUG_ON(!PageLocked(page)); | |
105 | return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ, | |
106 | page_to_pfn(page)); | |
107 | } | |
108 | ||
109 | static inline int is_migration_entry(swp_entry_t entry) | |
110 | { | |
111 | return unlikely(swp_type(entry) == SWP_MIGRATION_READ || | |
112 | swp_type(entry) == SWP_MIGRATION_WRITE); | |
113 | } | |
114 | ||
115 | static inline int is_write_migration_entry(swp_entry_t entry) | |
116 | { | |
117 | return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); | |
118 | } | |
119 | ||
120 | static inline struct page *migration_entry_to_page(swp_entry_t entry) | |
121 | { | |
122 | struct page *p = pfn_to_page(swp_offset(entry)); | |
123 | /* | |
124 | * Any use of migration entries may only occur while the | |
125 | * corresponding page is locked | |
126 | */ | |
127 | BUG_ON(!PageLocked(p)); | |
128 | return p; | |
129 | } | |
130 | ||
131 | static inline void make_migration_entry_read(swp_entry_t *entry) | |
132 | { | |
133 | *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry)); | |
134 | } | |
135 | ||
136 | extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, | |
137 | unsigned long address); | |
138 | #else | |
139 | ||
140 | #define make_migration_entry(page, write) swp_entry(0, 0) | |
5ec553a9 AM |
141 | static inline int is_migration_entry(swp_entry_t swp) |
142 | { | |
143 | return 0; | |
144 | } | |
0697212a CL |
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) | |
150 | { | |
151 | return 0; | |
152 | } | |
153 | ||
154 | #endif | |
155 | ||
a7420aa5 AK |
156 | #ifdef CONFIG_MEMORY_FAILURE |
157 | /* | |
158 | * Support for hardware poisoned pages | |
159 | */ | |
160 | static inline swp_entry_t make_hwpoison_entry(struct page *page) | |
161 | { | |
162 | BUG_ON(!PageLocked(page)); | |
163 | return swp_entry(SWP_HWPOISON, page_to_pfn(page)); | |
164 | } | |
165 | ||
166 | static inline int is_hwpoison_entry(swp_entry_t entry) | |
167 | { | |
168 | return swp_type(entry) == SWP_HWPOISON; | |
169 | } | |
170 | #else | |
171 | ||
172 | static inline swp_entry_t make_hwpoison_entry(struct page *page) | |
173 | { | |
174 | return swp_entry(0, 0); | |
175 | } | |
176 | ||
177 | static inline int is_hwpoison_entry(swp_entry_t swp) | |
178 | { | |
179 | return 0; | |
180 | } | |
181 | #endif | |
182 | ||
183 | #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) | |
184 | static inline int non_swap_entry(swp_entry_t entry) | |
185 | { | |
186 | return swp_type(entry) >= MAX_SWAPFILES; | |
187 | } | |
188 | #else | |
189 | static inline int non_swap_entry(swp_entry_t entry) | |
190 | { | |
191 | return 0; | |
192 | } | |
193 | #endif | |
a2c16d6c HD |
194 | |
195 | #endif /* _LINUX_SWAPOPS_H */ |