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a2c16d6c HD |
1 | #ifndef _LINUX_SWAPOPS_H |
2 | #define _LINUX_SWAPOPS_H | |
3 | ||
4 | #include <linux/radix-tree.h> | |
5 | ||
1da177e4 LT |
6 | /* |
7 | * swapcache pages are stored in the swapper_space radix tree. We want to | |
8 | * get good packing density in that tree, so the index should be dense in | |
9 | * the low-order bits. | |
10 | * | |
11 | * We arrange the `type' and `offset' fields so that `type' is at the five | |
e83a9596 | 12 | * high-order bits of the swp_entry_t and `offset' is right-aligned in the |
1da177e4 LT |
13 | * remaining bits. |
14 | * | |
15 | * swp_entry_t's are *never* stored anywhere in their arch-dependent format. | |
16 | */ | |
17 | #define SWP_TYPE_SHIFT(e) (sizeof(e.val) * 8 - MAX_SWAPFILES_SHIFT) | |
18 | #define SWP_OFFSET_MASK(e) ((1UL << SWP_TYPE_SHIFT(e)) - 1) | |
19 | ||
20 | /* | |
21 | * Store a type+offset into a swp_entry_t in an arch-independent format | |
22 | */ | |
23 | static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset) | |
24 | { | |
25 | swp_entry_t ret; | |
26 | ||
27 | ret.val = (type << SWP_TYPE_SHIFT(ret)) | | |
28 | (offset & SWP_OFFSET_MASK(ret)); | |
29 | return ret; | |
30 | } | |
31 | ||
32 | /* | |
33 | * Extract the `type' field from a swp_entry_t. The swp_entry_t is in | |
34 | * arch-independent format | |
35 | */ | |
36 | static inline unsigned swp_type(swp_entry_t entry) | |
37 | { | |
38 | return (entry.val >> SWP_TYPE_SHIFT(entry)); | |
39 | } | |
40 | ||
41 | /* | |
42 | * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in | |
43 | * arch-independent format | |
44 | */ | |
45 | static inline pgoff_t swp_offset(swp_entry_t entry) | |
46 | { | |
47 | return entry.val & SWP_OFFSET_MASK(entry); | |
48 | } | |
49 | ||
880cdf3a | 50 | #ifdef CONFIG_MMU |
698dd4ba MM |
51 | /* check whether a pte points to a swap entry */ |
52 | static inline int is_swap_pte(pte_t pte) | |
53 | { | |
54 | return !pte_none(pte) && !pte_present(pte) && !pte_file(pte); | |
55 | } | |
880cdf3a | 56 | #endif |
698dd4ba | 57 | |
1da177e4 LT |
58 | /* |
59 | * Convert the arch-dependent pte representation of a swp_entry_t into an | |
60 | * arch-independent swp_entry_t. | |
61 | */ | |
62 | static inline swp_entry_t pte_to_swp_entry(pte_t pte) | |
63 | { | |
64 | swp_entry_t arch_entry; | |
65 | ||
66 | BUG_ON(pte_file(pte)); | |
67 | arch_entry = __pte_to_swp_entry(pte); | |
68 | return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); | |
69 | } | |
70 | ||
71 | /* | |
72 | * Convert the arch-independent representation of a swp_entry_t into the | |
73 | * arch-dependent pte representation. | |
74 | */ | |
75 | static inline pte_t swp_entry_to_pte(swp_entry_t entry) | |
76 | { | |
77 | swp_entry_t arch_entry; | |
78 | ||
79 | arch_entry = __swp_entry(swp_type(entry), swp_offset(entry)); | |
80 | BUG_ON(pte_file(__swp_entry_to_pte(arch_entry))); | |
81 | return __swp_entry_to_pte(arch_entry); | |
82 | } | |
0697212a | 83 | |
a2c16d6c HD |
84 | static inline swp_entry_t radix_to_swp_entry(void *arg) |
85 | { | |
86 | swp_entry_t entry; | |
87 | ||
88 | entry.val = (unsigned long)arg >> RADIX_TREE_EXCEPTIONAL_SHIFT; | |
89 | return entry; | |
90 | } | |
91 | ||
92 | static inline void *swp_to_radix_entry(swp_entry_t entry) | |
93 | { | |
94 | unsigned long value; | |
95 | ||
96 | value = entry.val << RADIX_TREE_EXCEPTIONAL_SHIFT; | |
97 | return (void *)(value | RADIX_TREE_EXCEPTIONAL_ENTRY); | |
98 | } | |
99 | ||
0697212a CL |
100 | #ifdef CONFIG_MIGRATION |
101 | static inline swp_entry_t make_migration_entry(struct page *page, int write) | |
102 | { | |
103 | BUG_ON(!PageLocked(page)); | |
104 | return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ, | |
105 | page_to_pfn(page)); | |
106 | } | |
107 | ||
108 | static inline int is_migration_entry(swp_entry_t entry) | |
109 | { | |
110 | return unlikely(swp_type(entry) == SWP_MIGRATION_READ || | |
111 | swp_type(entry) == SWP_MIGRATION_WRITE); | |
112 | } | |
113 | ||
114 | static inline int is_write_migration_entry(swp_entry_t entry) | |
115 | { | |
116 | return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); | |
117 | } | |
118 | ||
119 | static inline struct page *migration_entry_to_page(swp_entry_t entry) | |
120 | { | |
121 | struct page *p = pfn_to_page(swp_offset(entry)); | |
122 | /* | |
123 | * Any use of migration entries may only occur while the | |
124 | * corresponding page is locked | |
125 | */ | |
126 | BUG_ON(!PageLocked(p)); | |
127 | return p; | |
128 | } | |
129 | ||
130 | static inline void make_migration_entry_read(swp_entry_t *entry) | |
131 | { | |
132 | *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry)); | |
133 | } | |
134 | ||
135 | extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, | |
136 | unsigned long address); | |
137 | #else | |
138 | ||
139 | #define make_migration_entry(page, write) swp_entry(0, 0) | |
5ec553a9 AM |
140 | static inline int is_migration_entry(swp_entry_t swp) |
141 | { | |
142 | return 0; | |
143 | } | |
0697212a CL |
144 | #define migration_entry_to_page(swp) NULL |
145 | static inline void make_migration_entry_read(swp_entry_t *entryp) { } | |
146 | static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, | |
147 | unsigned long address) { } | |
148 | static inline int is_write_migration_entry(swp_entry_t entry) | |
149 | { | |
150 | return 0; | |
151 | } | |
152 | ||
153 | #endif | |
154 | ||
a7420aa5 AK |
155 | #ifdef CONFIG_MEMORY_FAILURE |
156 | /* | |
157 | * Support for hardware poisoned pages | |
158 | */ | |
159 | static inline swp_entry_t make_hwpoison_entry(struct page *page) | |
160 | { | |
161 | BUG_ON(!PageLocked(page)); | |
162 | return swp_entry(SWP_HWPOISON, page_to_pfn(page)); | |
163 | } | |
164 | ||
165 | static inline int is_hwpoison_entry(swp_entry_t entry) | |
166 | { | |
167 | return swp_type(entry) == SWP_HWPOISON; | |
168 | } | |
169 | #else | |
170 | ||
171 | static inline swp_entry_t make_hwpoison_entry(struct page *page) | |
172 | { | |
173 | return swp_entry(0, 0); | |
174 | } | |
175 | ||
176 | static inline int is_hwpoison_entry(swp_entry_t swp) | |
177 | { | |
178 | return 0; | |
179 | } | |
180 | #endif | |
181 | ||
182 | #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) | |
183 | static inline int non_swap_entry(swp_entry_t entry) | |
184 | { | |
185 | return swp_type(entry) >= MAX_SWAPFILES; | |
186 | } | |
187 | #else | |
188 | static inline int non_swap_entry(swp_entry_t entry) | |
189 | { | |
190 | return 0; | |
191 | } | |
192 | #endif | |
a2c16d6c HD |
193 | |
194 | #endif /* _LINUX_SWAPOPS_H */ |