kernfs: fix ino wrap-around detection

[mirror_ubuntu-bionic-kernel.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0d15c7463ccef968f1d4fa22d77864678fe75b23..8976f7f1f98886d9466af1a6a0a09c2c54988408 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -154,7 +154,9 @@ extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
  * mmap() functions).
  */
 
-extern struct kmem_cache *vm_area_cachep;
+struct vm_area_struct *vm_area_alloc(struct mm_struct *);
+struct vm_area_struct *vm_area_dup(struct vm_area_struct *);
+void vm_area_free(struct vm_area_struct *);
 
 #ifndef CONFIG_MMU
 extern struct rb_root nommu_region_tree;
@@ -559,11 +561,6 @@ static inline void *kvmalloc_array(size_t n, size_t size, gfp_t flags)
 
 extern void kvfree(const void *addr);
 
-static inline atomic_t *compound_mapcount_ptr(struct page *page)
-{
-       return &page[1].compound_mapcount;
-}
-
 static inline int compound_mapcount(struct page *page)
 {
        VM_BUG_ON_PAGE(!PageCompound(page), page);
@@ -834,6 +831,10 @@ static inline bool is_device_public_page(const struct page *page)
 #endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
 
 
+/* 127: arbitrary random number, small enough to assemble well */
+#define page_ref_zero_or_close_to_overflow(page) \
+       ((unsigned int) page_ref_count(page) + 127u <= 127u)
+
 static inline void get_page(struct page *page)
 {
        page = compound_head(page);
@@ -841,8 +842,17 @@ static inline void get_page(struct page *page)
         * Getting a normal page or the head of a compound page
         * requires to already have an elevated page->_refcount.
         */
-       VM_BUG_ON_PAGE(page_ref_count(page) <= 0, page);
+       VM_BUG_ON_PAGE(page_ref_zero_or_close_to_overflow(page), page);
+       page_ref_inc(page);
+}
+
+static inline __must_check bool try_get_page(struct page *page)
+{
+       page = compound_head(page);
+       if (WARN_ON_ONCE(page_ref_count(page) <= 0))
+               return false;
        page_ref_inc(page);
+       return true;
 }
 
 static inline void put_page(struct page *page)
@@ -1667,11 +1677,15 @@ int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address);
 
 static inline void mm_inc_nr_puds(struct mm_struct *mm)
 {
+       if (mm_pud_folded(mm))
+               return;
        atomic_long_add(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes);
 }
 
 static inline void mm_dec_nr_puds(struct mm_struct *mm)
 {
+       if (mm_pud_folded(mm))
+               return;
        atomic_long_sub(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes);
 }
 #endif
@@ -1691,11 +1705,15 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
 
 static inline void mm_inc_nr_pmds(struct mm_struct *mm)
 {
+       if (mm_pmd_folded(mm))
+               return;
        atomic_long_add(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes);
 }
 
 static inline void mm_dec_nr_pmds(struct mm_struct *mm)
 {
+       if (mm_pmd_folded(mm))
+               return;
        atomic_long_sub(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes);
 }
 #endif
@@ -2396,6 +2414,12 @@ static inline struct vm_area_struct *find_exact_vma(struct mm_struct *mm,
        return vma;
 }
 
+static inline bool range_in_vma(struct vm_area_struct *vma,
+                               unsigned long start, unsigned long end)
+{
+       return (vma && vma->vm_start <= start && end <= vma->vm_end);
+}
+
 #ifdef CONFIG_MMU
 pgprot_t vm_get_page_prot(unsigned long vm_flags);
 void vma_set_page_prot(struct vm_area_struct *vma);