diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm.h | 34 | ||||
| -rw-r--r-- | include/linux/rmap.h | 14 |
2 files changed, 48 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 7d20b25c58f..449841413cf 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -15,6 +15,7 @@ #include <linux/fs.h> #include <linux/mutex.h> #include <linux/debug_locks.h> +#include <linux/backing-dev.h> struct mempolicy; struct anon_vma; @@ -810,6 +811,39 @@ struct shrinker; extern struct shrinker *set_shrinker(int, shrinker_t); extern void remove_shrinker(struct shrinker *shrinker); +/* + * Some shared mappigns will want the pages marked read-only + * to track write events. If so, we'll downgrade vm_page_prot + * to the private version (using protection_map[] without the + * VM_SHARED bit). + */ +static inline int vma_wants_writenotify(struct vm_area_struct *vma) +{ + unsigned int vm_flags = vma->vm_flags; + + /* If it was private or non-writable, the write bit is already clear */ + if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) + return 0; + + /* The backer wishes to know when pages are first written to? */ + if (vma->vm_ops && vma->vm_ops->page_mkwrite) + return 1; + + /* The open routine did something to the protections already? */ + if (pgprot_val(vma->vm_page_prot) != + pgprot_val(protection_map[vm_flags & + (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)])) + return 0; + + /* Specialty mapping? */ + if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE)) + return 0; + + /* Can the mapping track the dirty pages? */ + return vma->vm_file && vma->vm_file->f_mapping && + mapping_cap_account_dirty(vma->vm_file->f_mapping); +} + extern pte_t *FASTCALL(get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl)); int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address); diff --git a/include/linux/rmap.h b/include/linux/rmap.h index bf97b090001..db2c1df4fef 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -103,6 +103,14 @@ pte_t *page_check_address(struct page *, struct mm_struct *, */ 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) @@ -112,6 +120,12 @@ unsigned long page_address_in_vma(struct page *, struct vm_area_struct *); #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 */ /* |