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1da177e4 LT |
1 | #ifndef _LINUX_RMAP_H |
2 | #define _LINUX_RMAP_H | |
3 | /* | |
4 | * Declarations for Reverse Mapping functions in mm/rmap.c | |
5 | */ | |
6 | ||
1da177e4 LT |
7 | #include <linux/list.h> |
8 | #include <linux/slab.h> | |
9 | #include <linux/mm.h> | |
2b575eb6 | 10 | #include <linux/mutex.h> |
bed7161a | 11 | #include <linux/memcontrol.h> |
1da177e4 LT |
12 | |
13 | /* | |
14 | * The anon_vma heads a list of private "related" vmas, to scan if | |
15 | * an anonymous page pointing to this anon_vma needs to be unmapped: | |
16 | * the vmas on the list will be related by forking, or by splitting. | |
17 | * | |
18 | * Since vmas come and go as they are split and merged (particularly | |
19 | * in mprotect), the mapping field of an anonymous page cannot point | |
20 | * directly to a vma: instead it points to an anon_vma, on whose list | |
21 | * the related vmas can be easily linked or unlinked. | |
22 | * | |
23 | * After unlinking the last vma on the list, we must garbage collect | |
24 | * the anon_vma object itself: we're guaranteed no page can be | |
25 | * pointing to this anon_vma once its vma list is empty. | |
26 | */ | |
27 | struct anon_vma { | |
5c341ee1 | 28 | struct anon_vma *root; /* Root of this anon_vma tree */ |
2b575eb6 | 29 | struct mutex mutex; /* Serialize access to vma list */ |
7f60c214 | 30 | /* |
83813267 | 31 | * The refcount is taken on an anon_vma when there is no |
7f60c214 MG |
32 | * guarantee that the vma of page tables will exist for |
33 | * the duration of the operation. A caller that takes | |
34 | * the reference is responsible for clearing up the | |
35 | * anon_vma if they are the last user on release | |
36 | */ | |
83813267 PZ |
37 | atomic_t refcount; |
38 | ||
7906d00c | 39 | /* |
bf181b9f | 40 | * NOTE: the LSB of the rb_root.rb_node is set by |
7906d00c | 41 | * mm_take_all_locks() _after_ taking the above lock. So the |
bf181b9f | 42 | * rb_root must only be read/written after taking the above lock |
7906d00c AA |
43 | * to be sure to see a valid next pointer. The LSB bit itself |
44 | * is serialized by a system wide lock only visible to | |
45 | * mm_take_all_locks() (mm_all_locks_mutex). | |
46 | */ | |
bf181b9f | 47 | struct rb_root rb_root; /* Interval tree of private "related" vmas */ |
5beb4930 RR |
48 | }; |
49 | ||
50 | /* | |
51 | * The copy-on-write semantics of fork mean that an anon_vma | |
52 | * can become associated with multiple processes. Furthermore, | |
53 | * each child process will have its own anon_vma, where new | |
54 | * pages for that process are instantiated. | |
55 | * | |
56 | * This structure allows us to find the anon_vmas associated | |
57 | * with a VMA, or the VMAs associated with an anon_vma. | |
58 | * The "same_vma" list contains the anon_vma_chains linking | |
59 | * all the anon_vmas associated with this VMA. | |
bf181b9f | 60 | * The "rb" field indexes on an interval tree the anon_vma_chains |
5beb4930 RR |
61 | * which link all the VMAs associated with this anon_vma. |
62 | */ | |
63 | struct anon_vma_chain { | |
64 | struct vm_area_struct *vma; | |
65 | struct anon_vma *anon_vma; | |
66 | struct list_head same_vma; /* locked by mmap_sem & page_table_lock */ | |
bf181b9f ML |
67 | struct rb_node rb; /* locked by anon_vma->mutex */ |
68 | unsigned long rb_subtree_last; | |
1da177e4 LT |
69 | }; |
70 | ||
71 | #ifdef CONFIG_MMU | |
76545066 RR |
72 | static inline void get_anon_vma(struct anon_vma *anon_vma) |
73 | { | |
83813267 | 74 | atomic_inc(&anon_vma->refcount); |
76545066 RR |
75 | } |
76 | ||
01d8b20d PZ |
77 | void __put_anon_vma(struct anon_vma *anon_vma); |
78 | ||
79 | static inline void put_anon_vma(struct anon_vma *anon_vma) | |
80 | { | |
81 | if (atomic_dec_and_test(&anon_vma->refcount)) | |
82 | __put_anon_vma(anon_vma); | |
83 | } | |
1da177e4 | 84 | |
3ca7b3c5 HD |
85 | static inline struct anon_vma *page_anon_vma(struct page *page) |
86 | { | |
87 | if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != | |
88 | PAGE_MAPPING_ANON) | |
89 | return NULL; | |
90 | return page_rmapping(page); | |
91 | } | |
92 | ||
bb4a340e | 93 | static inline void vma_lock_anon_vma(struct vm_area_struct *vma) |
1da177e4 LT |
94 | { |
95 | struct anon_vma *anon_vma = vma->anon_vma; | |
96 | if (anon_vma) | |
2b575eb6 | 97 | mutex_lock(&anon_vma->root->mutex); |
1da177e4 LT |
98 | } |
99 | ||
bb4a340e | 100 | static inline void vma_unlock_anon_vma(struct vm_area_struct *vma) |
1da177e4 LT |
101 | { |
102 | struct anon_vma *anon_vma = vma->anon_vma; | |
103 | if (anon_vma) | |
2b575eb6 | 104 | mutex_unlock(&anon_vma->root->mutex); |
1da177e4 LT |
105 | } |
106 | ||
cba48b98 RR |
107 | static inline void anon_vma_lock(struct anon_vma *anon_vma) |
108 | { | |
2b575eb6 | 109 | mutex_lock(&anon_vma->root->mutex); |
cba48b98 RR |
110 | } |
111 | ||
112 | static inline void anon_vma_unlock(struct anon_vma *anon_vma) | |
113 | { | |
2b575eb6 | 114 | mutex_unlock(&anon_vma->root->mutex); |
cba48b98 RR |
115 | } |
116 | ||
1da177e4 LT |
117 | /* |
118 | * anon_vma helper functions. | |
119 | */ | |
120 | void anon_vma_init(void); /* create anon_vma_cachep */ | |
121 | int anon_vma_prepare(struct vm_area_struct *); | |
5beb4930 RR |
122 | void unlink_anon_vmas(struct vm_area_struct *); |
123 | int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *); | |
124 | int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *); | |
1da177e4 | 125 | |
5beb4930 RR |
126 | static inline void anon_vma_merge(struct vm_area_struct *vma, |
127 | struct vm_area_struct *next) | |
128 | { | |
129 | VM_BUG_ON(vma->anon_vma != next->anon_vma); | |
130 | unlink_anon_vmas(next); | |
131 | } | |
132 | ||
01d8b20d PZ |
133 | struct anon_vma *page_get_anon_vma(struct page *page); |
134 | ||
1da177e4 LT |
135 | /* |
136 | * rmap interfaces called when adding or removing pte of page | |
137 | */ | |
c44b6743 | 138 | void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
1da177e4 | 139 | void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
ad8c2ee8 RR |
140 | void do_page_add_anon_rmap(struct page *, struct vm_area_struct *, |
141 | unsigned long, int); | |
9617d95e | 142 | void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); |
1da177e4 | 143 | void page_add_file_rmap(struct page *); |
edc315fd | 144 | void page_remove_rmap(struct page *); |
1da177e4 | 145 | |
0fe6e20b NH |
146 | void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *, |
147 | unsigned long); | |
148 | void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *, | |
149 | unsigned long); | |
150 | ||
21333b2b | 151 | static inline void page_dup_rmap(struct page *page) |
1da177e4 LT |
152 | { |
153 | atomic_inc(&page->_mapcount); | |
154 | } | |
155 | ||
156 | /* | |
157 | * Called from mm/vmscan.c to handle paging out | |
158 | */ | |
6fe6b7e3 | 159 | int page_referenced(struct page *, int is_locked, |
72835c86 | 160 | struct mem_cgroup *memcg, unsigned long *vm_flags); |
5ad64688 HD |
161 | int page_referenced_one(struct page *, struct vm_area_struct *, |
162 | unsigned long address, unsigned int *mapcount, unsigned long *vm_flags); | |
163 | ||
14fa31b8 AK |
164 | enum ttu_flags { |
165 | TTU_UNMAP = 0, /* unmap mode */ | |
166 | TTU_MIGRATION = 1, /* migration mode */ | |
167 | TTU_MUNLOCK = 2, /* munlock mode */ | |
168 | TTU_ACTION_MASK = 0xff, | |
169 | ||
170 | TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */ | |
171 | TTU_IGNORE_ACCESS = (1 << 9), /* don't age */ | |
888b9f7c | 172 | TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */ |
14fa31b8 AK |
173 | }; |
174 | #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK) | |
175 | ||
176 | int try_to_unmap(struct page *, enum ttu_flags flags); | |
5ad64688 HD |
177 | int try_to_unmap_one(struct page *, struct vm_area_struct *, |
178 | unsigned long address, enum ttu_flags flags); | |
1da177e4 | 179 | |
ceffc078 CO |
180 | /* |
181 | * Called from mm/filemap_xip.c to unmap empty zero page | |
182 | */ | |
e9a81a82 | 183 | pte_t *__page_check_address(struct page *, struct mm_struct *, |
479db0bf | 184 | unsigned long, spinlock_t **, int); |
ceffc078 | 185 | |
e9a81a82 NK |
186 | static inline pte_t *page_check_address(struct page *page, struct mm_struct *mm, |
187 | unsigned long address, | |
188 | spinlock_t **ptlp, int sync) | |
189 | { | |
190 | pte_t *ptep; | |
191 | ||
192 | __cond_lock(*ptlp, ptep = __page_check_address(page, mm, address, | |
193 | ptlp, sync)); | |
194 | return ptep; | |
195 | } | |
196 | ||
1da177e4 LT |
197 | /* |
198 | * Used by swapoff to help locate where page is expected in vma. | |
199 | */ | |
200 | unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); | |
201 | ||
d08b3851 PZ |
202 | /* |
203 | * Cleans the PTEs of shared mappings. | |
204 | * (and since clean PTEs should also be readonly, write protects them too) | |
205 | * | |
206 | * returns the number of cleaned PTEs. | |
207 | */ | |
208 | int page_mkclean(struct page *); | |
209 | ||
b291f000 NP |
210 | /* |
211 | * called in munlock()/munmap() path to check for other vmas holding | |
212 | * the page mlocked. | |
213 | */ | |
214 | int try_to_munlock(struct page *); | |
b291f000 | 215 | |
10be22df AK |
216 | /* |
217 | * Called by memory-failure.c to kill processes. | |
218 | */ | |
25aeeb04 | 219 | struct anon_vma *page_lock_anon_vma(struct page *page); |
10be22df | 220 | void page_unlock_anon_vma(struct anon_vma *anon_vma); |
6a46079c | 221 | int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma); |
10be22df | 222 | |
e9995ef9 HD |
223 | /* |
224 | * Called by migrate.c to remove migration ptes, but might be used more later. | |
225 | */ | |
226 | int rmap_walk(struct page *page, int (*rmap_one)(struct page *, | |
227 | struct vm_area_struct *, unsigned long, void *), void *arg); | |
228 | ||
1da177e4 LT |
229 | #else /* !CONFIG_MMU */ |
230 | ||
231 | #define anon_vma_init() do {} while (0) | |
232 | #define anon_vma_prepare(vma) (0) | |
233 | #define anon_vma_link(vma) do {} while (0) | |
234 | ||
01ff53f4 | 235 | static inline int page_referenced(struct page *page, int is_locked, |
72835c86 | 236 | struct mem_cgroup *memcg, |
01ff53f4 MF |
237 | unsigned long *vm_flags) |
238 | { | |
239 | *vm_flags = 0; | |
64574746 | 240 | return 0; |
01ff53f4 MF |
241 | } |
242 | ||
a48d07af | 243 | #define try_to_unmap(page, refs) SWAP_FAIL |
1da177e4 | 244 | |
d08b3851 PZ |
245 | static inline int page_mkclean(struct page *page) |
246 | { | |
247 | return 0; | |
248 | } | |
249 | ||
250 | ||
1da177e4 LT |
251 | #endif /* CONFIG_MMU */ |
252 | ||
253 | /* | |
254 | * Return values of try_to_unmap | |
255 | */ | |
256 | #define SWAP_SUCCESS 0 | |
257 | #define SWAP_AGAIN 1 | |
258 | #define SWAP_FAIL 2 | |
b291f000 | 259 | #define SWAP_MLOCK 3 |
1da177e4 LT |
260 | |
261 | #endif /* _LINUX_RMAP_H */ |