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/list.h> 8 #include <linux/slab.h> 9 #include <linux/mm.h> 10 #include <linux/spinlock.h> 11 12 /* 13 * The anon_vma heads a list of private "related" vmas, to scan if 14 * an anonymous page pointing to this anon_vma needs to be unmapped: 15 * the vmas on the list will be related by forking, or by splitting. 16 * 17 * Since vmas come and go as they are split and merged (particularly 18 * in mprotect), the mapping field of an anonymous page cannot point 19 * directly to a vma: instead it points to an anon_vma, on whose list 20 * the related vmas can be easily linked or unlinked. 21 * 22 * After unlinking the last vma on the list, we must garbage collect 23 * the anon_vma object itself: we're guaranteed no page can be 24 * pointing to this anon_vma once its vma list is empty. 25 */ 26 struct anon_vma { 27 spinlock_t lock; /* Serialize access to vma list */ 28 struct list_head head; /* List of private "related" vmas */ 29 }; 30 31 #ifdef CONFIG_MMU 32 33 extern struct kmem_cache *anon_vma_cachep; 34 35 static inline struct anon_vma *anon_vma_alloc(void) 36 { 37 return kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL); 38 } 39 40 static inline void anon_vma_free(struct anon_vma *anon_vma) 41 { 42 kmem_cache_free(anon_vma_cachep, anon_vma); 43 } 44 45 static inline void anon_vma_lock(struct vm_area_struct *vma) 46 { 47 struct anon_vma *anon_vma = vma->anon_vma; 48 if (anon_vma) 49 spin_lock(&anon_vma->lock); 50 } 51 52 static inline void anon_vma_unlock(struct vm_area_struct *vma) 53 { 54 struct anon_vma *anon_vma = vma->anon_vma; 55 if (anon_vma) 56 spin_unlock(&anon_vma->lock); 57 } 58 59 /* 60 * anon_vma helper functions. 61 */ 62 void anon_vma_init(void); /* create anon_vma_cachep */ 63 int anon_vma_prepare(struct vm_area_struct *); 64 void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *); 65 void anon_vma_unlink(struct vm_area_struct *); 66 void anon_vma_link(struct vm_area_struct *); 67 void __anon_vma_link(struct vm_area_struct *); 68 69 /* 70 * rmap interfaces called when adding or removing pte of page 71 */ 72 void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); 73 void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); 74 void page_add_file_rmap(struct page *); 75 void page_remove_rmap(struct page *, struct vm_area_struct *); 76 77 /** 78 * page_dup_rmap - duplicate pte mapping to a page 79 * @page: the page to add the mapping to 80 * 81 * For copy_page_range only: minimal extract from page_add_rmap, 82 * avoiding unnecessary tests (already checked) so it's quicker. 83 */ 84 static inline void page_dup_rmap(struct page *page) 85 { 86 atomic_inc(&page->_mapcount); 87 } 88 89 /* 90 * Called from mm/vmscan.c to handle paging out 91 */ 92 int page_referenced(struct page *, int is_locked); 93 int try_to_unmap(struct page *, int ignore_refs); 94 95 /* 96 * Called from mm/filemap_xip.c to unmap empty zero page 97 */ 98 pte_t *page_check_address(struct page *, struct mm_struct *, 99 unsigned long, spinlock_t **); 100 101 /* 102 * Used by swapoff to help locate where page is expected in vma. 103 */ 104 unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); 105 106 /* 107 * Cleans the PTEs of shared mappings. 108 * (and since clean PTEs should also be readonly, write protects them too) 109 * 110 * returns the number of cleaned PTEs. 111 */ 112 int page_mkclean(struct page *); 113 114 #else /* !CONFIG_MMU */ 115 116 #define anon_vma_init() do {} while (0) 117 #define anon_vma_prepare(vma) (0) 118 #define anon_vma_link(vma) do {} while (0) 119 120 #define page_referenced(page,l) TestClearPageReferenced(page) 121 #define try_to_unmap(page, refs) SWAP_FAIL 122 123 static inline int page_mkclean(struct page *page) 124 { 125 return 0; 126 } 127 128 129 #endif /* CONFIG_MMU */ 130 131 /* 132 * Return values of try_to_unmap 133 */ 134 #define SWAP_SUCCESS 0 135 #define SWAP_AGAIN 1 136 #define SWAP_FAIL 2 137 138 #endif /* _LINUX_RMAP_H */ 139