#ifndef _LINUX_RMAP_H #define _LINUX_RMAP_H /* * Declarations for Reverse Mapping functions in mm/rmap.c */ #include <linux/list.h> #include <linux/slab.h> #include <linux/mm.h> #include <linux/spinlock.h> /* * The anon_vma heads a list of private "related" vmas, to scan if * an anonymous page pointing to this anon_vma needs to be unmapped: * the vmas on the list will be related by forking, or by splitting. * * Since vmas come and go as they are split and merged (particularly * in mprotect), the mapping field of an anonymous page cannot point * directly to a vma: instead it points to an anon_vma, on whose list * the related vmas can be easily linked or unlinked. * * After unlinking the last vma on the list, we must garbage collect * the anon_vma object itself: we're guaranteed no page can be * pointing to this anon_vma once its vma list is empty. */ struct anon_vma { spinlock_t lock; /* Serialize access to vma list */ struct list_head head; /* List of private "related" vmas */ }; #ifdef CONFIG_MMU extern struct kmem_cache *anon_vma_cachep; static inline struct anon_vma *anon_vma_alloc(void) { return kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL); } static inline void anon_vma_free(struct anon_vma *anon_vma) { kmem_cache_free(anon_vma_cachep, anon_vma); } static inline void anon_vma_lock(struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; if (anon_vma) spin_lock(&anon_vma->lock); } static inline void anon_vma_unlock(struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; if (anon_vma) spin_unlock(&anon_vma->lock); } /* * anon_vma helper functions. */ void anon_vma_init(void); /* create anon_vma_cachep */ int anon_vma_prepare(struct vm_area_struct *); void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *); void anon_vma_unlink(struct vm_area_struct *); void anon_vma_link(struct vm_area_struct *); void __anon_vma_link(struct vm_area_struct *); /* * rmap interfaces called when adding or removing pte of page */ void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long); void page_add_file_rmap(struct page *); void page_remove_rmap(struct page *, struct vm_area_struct *); /** * page_dup_rmap - duplicate pte mapping to a page * @page: the page to add the mapping to * * For copy_page_range only: minimal extract from page_add_rmap, * avoiding unnecessary tests (already checked) so it's quicker. */ static inline void page_dup_rmap(struct page *page) { atomic_inc(&page->_mapcount); } /* * Called from mm/vmscan.c to handle paging out */ int page_referenced(struct page *, int is_locked); int try_to_unmap(struct page *, int ignore_refs); /* * Called from mm/filemap_xip.c to unmap empty zero page */ pte_t *page_check_address(struct page *, struct mm_struct *, unsigned long, spinlock_t **); /* * Used by swapoff to help locate where page is expected in vma. */ unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); /* * Cleans the PTEs of shared mappings. * (and since clean PTEs should also be readonly, write protects them too) * * returns the number of cleaned PTEs. */ int page_mkclean(struct page *); #else /* !CONFIG_MMU */ #define anon_vma_init() do {} while (0) #define anon_vma_prepare(vma) (0) #define anon_vma_link(vma) do {} while (0) #define page_referenced(page,l) TestClearPageReferenced(page) #define try_to_unmap(page, refs) SWAP_FAIL static inline int page_mkclean(struct page *page) { return 0; } #endif /* CONFIG_MMU */ /* * Return values of try_to_unmap */ #define SWAP_SUCCESS 0 #define SWAP_AGAIN 1 #define SWAP_FAIL 2 #endif /* _LINUX_RMAP_H */