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1 | #ifndef _LINUX_RMAP_H | |
2 | #define _LINUX_RMAP_H | |
3 | /* | |
4 | * Declarations for Reverse Mapping functions in mm/rmap.c | |
5 | */ | |
6 | ||
7 | #include <linux/config.h> | |
8 | #include <linux/list.h> | |
9 | #include <linux/slab.h> | |
10 | #include <linux/mm.h> | |
11 | #include <linux/spinlock.h> | |
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 { | |
28 | spinlock_t lock; /* Serialize access to vma list */ | |
29 | struct list_head head; /* List of private "related" vmas */ | |
30 | }; | |
31 | ||
32 | #ifdef CONFIG_MMU | |
33 | ||
34 | extern kmem_cache_t *anon_vma_cachep; | |
35 | ||
36 | static inline struct anon_vma *anon_vma_alloc(void) | |
37 | { | |
38 | return kmem_cache_alloc(anon_vma_cachep, SLAB_KERNEL); | |
39 | } | |
40 | ||
41 | static inline void anon_vma_free(struct anon_vma *anon_vma) | |
42 | { | |
43 | kmem_cache_free(anon_vma_cachep, anon_vma); | |
44 | } | |
45 | ||
46 | static inline void anon_vma_lock(struct vm_area_struct *vma) | |
47 | { | |
48 | struct anon_vma *anon_vma = vma->anon_vma; | |
49 | if (anon_vma) | |
50 | spin_lock(&anon_vma->lock); | |
51 | } | |
52 | ||
53 | static inline void anon_vma_unlock(struct vm_area_struct *vma) | |
54 | { | |
55 | struct anon_vma *anon_vma = vma->anon_vma; | |
56 | if (anon_vma) | |
57 | spin_unlock(&anon_vma->lock); | |
58 | } | |
59 | ||
60 | /* | |
61 | * anon_vma helper functions. | |
62 | */ | |
63 | void anon_vma_init(void); /* create anon_vma_cachep */ | |
64 | int anon_vma_prepare(struct vm_area_struct *); | |
65 | void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *); | |
66 | void anon_vma_unlink(struct vm_area_struct *); | |
67 | void anon_vma_link(struct vm_area_struct *); | |
68 | void __anon_vma_link(struct vm_area_struct *); | |
69 | ||
70 | /* | |
71 | * rmap interfaces called when adding or removing pte of page | |
72 | */ | |
73 | void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); | |
74 | void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); | |
75 | void page_add_file_rmap(struct page *); | |
76 | void page_remove_rmap(struct page *); | |
77 | ||
78 | /** | |
79 | * page_dup_rmap - duplicate pte mapping to a page | |
80 | * @page: the page to add the mapping to | |
81 | * | |
82 | * For copy_page_range only: minimal extract from page_add_rmap, | |
83 | * avoiding unnecessary tests (already checked) so it's quicker. | |
84 | */ | |
85 | static inline void page_dup_rmap(struct page *page) | |
86 | { | |
87 | atomic_inc(&page->_mapcount); | |
88 | } | |
89 | ||
90 | /* | |
91 | * Called from mm/vmscan.c to handle paging out | |
92 | */ | |
93 | int page_referenced(struct page *, int is_locked); | |
94 | int try_to_unmap(struct page *); | |
95 | ||
96 | /* | |
97 | * Called from mm/filemap_xip.c to unmap empty zero page | |
98 | */ | |
99 | pte_t *page_check_address(struct page *, struct mm_struct *, | |
100 | unsigned long, spinlock_t **); | |
101 | ||
102 | /* | |
103 | * Used by swapoff to help locate where page is expected in vma. | |
104 | */ | |
105 | unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); | |
106 | ||
107 | #else /* !CONFIG_MMU */ | |
108 | ||
109 | #define anon_vma_init() do {} while (0) | |
110 | #define anon_vma_prepare(vma) (0) | |
111 | #define anon_vma_link(vma) do {} while (0) | |
112 | ||
113 | #define page_referenced(page,l) TestClearPageReferenced(page) | |
114 | #define try_to_unmap(page) SWAP_FAIL | |
115 | ||
116 | #endif /* CONFIG_MMU */ | |
117 | ||
118 | /* | |
119 | * Return values of try_to_unmap | |
120 | */ | |
121 | #define SWAP_SUCCESS 0 | |
122 | #define SWAP_AGAIN 1 | |
123 | #define SWAP_FAIL 2 | |
124 | ||
125 | #endif /* _LINUX_RMAP_H */ |