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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 | * | |
9b15b817 | 12 | * We arrange the `type' and `offset' fields so that `type' is at the seven |
e83a9596 | 13 | * high-order bits of the swp_entry_t and `offset' is right-aligned in the |
9b15b817 HD |
14 | * remaining bits. Although `type' itself needs only five bits, we allow for |
15 | * shmem/tmpfs to shift it all up a further two bits: see swp_to_radix_entry(). | |
1da177e4 LT |
16 | * |
17 | * swp_entry_t's are *never* stored anywhere in their arch-dependent format. | |
18 | */ | |
9b15b817 HD |
19 | #define SWP_TYPE_SHIFT(e) ((sizeof(e.val) * 8) - \ |
20 | (MAX_SWAPFILES_SHIFT + RADIX_TREE_EXCEPTIONAL_SHIFT)) | |
1da177e4 LT |
21 | #define SWP_OFFSET_MASK(e) ((1UL << SWP_TYPE_SHIFT(e)) - 1) |
22 | ||
23 | /* | |
24 | * Store a type+offset into a swp_entry_t in an arch-independent format | |
25 | */ | |
26 | static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset) | |
27 | { | |
28 | swp_entry_t ret; | |
29 | ||
30 | ret.val = (type << SWP_TYPE_SHIFT(ret)) | | |
31 | (offset & SWP_OFFSET_MASK(ret)); | |
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(entry)); | |
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(entry); | |
51 | } | |
52 | ||
880cdf3a | 53 | #ifdef CONFIG_MMU |
698dd4ba MM |
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) && !pte_file(pte); | |
58 | } | |
880cdf3a | 59 | #endif |
698dd4ba | 60 | |
1da177e4 LT |
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 | BUG_ON(pte_file(pte)); | |
70 | arch_entry = __pte_to_swp_entry(pte); | |
71 | return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); | |
72 | } | |
73 | ||
74 | /* | |
75 | * Convert the arch-independent representation of a swp_entry_t into the | |
76 | * arch-dependent pte representation. | |
77 | */ | |
78 | static inline pte_t swp_entry_to_pte(swp_entry_t entry) | |
79 | { | |
80 | swp_entry_t arch_entry; | |
81 | ||
82 | arch_entry = __swp_entry(swp_type(entry), swp_offset(entry)); | |
83 | BUG_ON(pte_file(__swp_entry_to_pte(arch_entry))); | |
84 | return __swp_entry_to_pte(arch_entry); | |
85 | } | |
0697212a | 86 | |
a2c16d6c HD |
87 | static inline swp_entry_t radix_to_swp_entry(void *arg) |
88 | { | |
89 | swp_entry_t entry; | |
90 | ||
91 | entry.val = (unsigned long)arg >> RADIX_TREE_EXCEPTIONAL_SHIFT; | |
92 | return entry; | |
93 | } | |
94 | ||
95 | static inline void *swp_to_radix_entry(swp_entry_t entry) | |
96 | { | |
97 | unsigned long value; | |
98 | ||
99 | value = entry.val << RADIX_TREE_EXCEPTIONAL_SHIFT; | |
100 | return (void *)(value | RADIX_TREE_EXCEPTIONAL_ENTRY); | |
101 | } | |
102 | ||
0697212a CL |
103 | #ifdef CONFIG_MIGRATION |
104 | static inline swp_entry_t make_migration_entry(struct page *page, int write) | |
105 | { | |
106 | BUG_ON(!PageLocked(page)); | |
107 | return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ, | |
108 | page_to_pfn(page)); | |
109 | } | |
110 | ||
111 | static inline int is_migration_entry(swp_entry_t entry) | |
112 | { | |
113 | return unlikely(swp_type(entry) == SWP_MIGRATION_READ || | |
114 | swp_type(entry) == SWP_MIGRATION_WRITE); | |
115 | } | |
116 | ||
117 | static inline int is_write_migration_entry(swp_entry_t entry) | |
118 | { | |
119 | return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); | |
120 | } | |
121 | ||
122 | static inline struct page *migration_entry_to_page(swp_entry_t entry) | |
123 | { | |
124 | struct page *p = pfn_to_page(swp_offset(entry)); | |
125 | /* | |
126 | * Any use of migration entries may only occur while the | |
127 | * corresponding page is locked | |
128 | */ | |
129 | BUG_ON(!PageLocked(p)); | |
130 | return p; | |
131 | } | |
132 | ||
133 | static inline void make_migration_entry_read(swp_entry_t *entry) | |
134 | { | |
135 | *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry)); | |
136 | } | |
137 | ||
138 | extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, | |
139 | unsigned long address); | |
30dad309 | 140 | extern void migration_entry_wait_huge(struct mm_struct *mm, pte_t *pte); |
0697212a CL |
141 | #else |
142 | ||
143 | #define make_migration_entry(page, write) swp_entry(0, 0) | |
5ec553a9 AM |
144 | static inline int is_migration_entry(swp_entry_t swp) |
145 | { | |
146 | return 0; | |
147 | } | |
0697212a CL |
148 | #define migration_entry_to_page(swp) NULL |
149 | static inline void make_migration_entry_read(swp_entry_t *entryp) { } | |
150 | static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, | |
151 | unsigned long address) { } | |
30dad309 NH |
152 | static inline void migration_entry_wait_huge(struct mm_struct *mm, |
153 | pte_t *pte) { } | |
0697212a CL |
154 | static inline int is_write_migration_entry(swp_entry_t entry) |
155 | { | |
156 | return 0; | |
157 | } | |
158 | ||
159 | #endif | |
160 | ||
a7420aa5 AK |
161 | #ifdef CONFIG_MEMORY_FAILURE |
162 | /* | |
163 | * Support for hardware poisoned pages | |
164 | */ | |
165 | static inline swp_entry_t make_hwpoison_entry(struct page *page) | |
166 | { | |
167 | BUG_ON(!PageLocked(page)); | |
168 | return swp_entry(SWP_HWPOISON, page_to_pfn(page)); | |
169 | } | |
170 | ||
171 | static inline int is_hwpoison_entry(swp_entry_t entry) | |
172 | { | |
173 | return swp_type(entry) == SWP_HWPOISON; | |
174 | } | |
175 | #else | |
176 | ||
177 | static inline swp_entry_t make_hwpoison_entry(struct page *page) | |
178 | { | |
179 | return swp_entry(0, 0); | |
180 | } | |
181 | ||
182 | static inline int is_hwpoison_entry(swp_entry_t swp) | |
183 | { | |
184 | return 0; | |
185 | } | |
186 | #endif | |
187 | ||
188 | #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) | |
189 | static inline int non_swap_entry(swp_entry_t entry) | |
190 | { | |
191 | return swp_type(entry) >= MAX_SWAPFILES; | |
192 | } | |
193 | #else | |
194 | static inline int non_swap_entry(swp_entry_t entry) | |
195 | { | |
196 | return 0; | |
197 | } | |
198 | #endif | |
a2c16d6c HD |
199 | |
200 | #endif /* _LINUX_SWAPOPS_H */ |