1 files changed, 53 insertions, 48 deletions

diff --git a/mm/internal.h b/mm/internal.h
index 38e24b8..a38a21e 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -13,6 +13,7 @@
 
 #include <linux/fs.h>
 #include <linux/mm.h>
+#include <linux/pagemap.h>
 
 /*
  * The set of flags that only affect watermark checking and reclaim
@@ -66,50 +67,6 @@ static inline void set_page_refcounted(struct page *page)
 	set_page_count(page, 1);
 }
 
-static inline void __get_page_tail_foll(struct page *page,
-					bool get_page_head)
-{
-	/*
-	 * If we're getting a tail page, the elevated page->_count is
-	 * required only in the head page and we will elevate the head
-	 * page->_count and tail page->_mapcount.
-	 *
-	 * We elevate page_tail->_mapcount for tail pages to force
-	 * page_tail->_count to be zero at all times to avoid getting
-	 * false positives from get_page_unless_zero() with
-	 * speculative page access (like in
-	 * page_cache_get_speculative()) on tail pages.
-	 */
-	VM_BUG_ON_PAGE(atomic_read(&compound_head(page)->_count) <= 0, page);
-	if (get_page_head)
-		atomic_inc(&compound_head(page)->_count);
-	get_huge_page_tail(page);
-}
-
-/*
- * This is meant to be called as the FOLL_GET operation of
- * follow_page() and it must be called while holding the proper PT
- * lock while the pte (or pmd_trans_huge) is still mapping the page.
- */
-static inline void get_page_foll(struct page *page)
-{
-	if (unlikely(PageTail(page)))
-		/*
-		 * This is safe only because
-		 * __split_huge_page_refcount() can't run under
-		 * get_page_foll() because we hold the proper PT lock.
-		 */
-		__get_page_tail_foll(page, true);
-	else {
-		/*
-		 * Getting a normal page or the head of a compound page
-		 * requires to already have an elevated page->_count.
-		 */
-		VM_BUG_ON_PAGE(atomic_read(&page->_count) <= 0, page);
-		atomic_inc(&page->_count);
-	}
-}
-
 extern unsigned long highest_memmap_pfn;
 
 /*
@@ -259,6 +216,37 @@ static inline bool is_cow_mapping(vm_flags_t flags)
 	return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
 }
 
+/*
+ * These three helpers classifies VMAs for virtual memory accounting.
+ */
+
+/*
+ * Executable code area - executable, not writable, not stack
+ */
+static inline bool is_exec_mapping(vm_flags_t flags)
+{
+	return (flags & (VM_EXEC | VM_WRITE | VM_STACK)) == VM_EXEC;
+}
+
+/*
+ * Stack area - atomatically grows in one direction
+ *
+ * VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous:
+ * do_mmap() forbids all other combinations.
+ */
+static inline bool is_stack_mapping(vm_flags_t flags)
+{
+	return (flags & VM_STACK) == VM_STACK;
+}
+
+/*
+ * Data area - private, writable, not stack
+ */
+static inline bool is_data_mapping(vm_flags_t flags)
+{
+	return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) == VM_WRITE;
+}
+
 /* mm/util.c */
 void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
 		struct vm_area_struct *prev, struct rb_node *rb_parent);
@@ -309,10 +297,27 @@ static inline void mlock_migrate_page(struct page *newpage, struct page *page)
 
 extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-extern unsigned long vma_address(struct page *page,
-				 struct vm_area_struct *vma);
-#endif
+/*
+ * At what user virtual address is page expected in @vma?
+ */
+static inline unsigned long
+__vma_address(struct page *page, struct vm_area_struct *vma)
+{
+	pgoff_t pgoff = page_to_pgoff(page);
+	return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+}
+
+static inline unsigned long
+vma_address(struct page *page, struct vm_area_struct *vma)
+{
+	unsigned long address = __vma_address(page, vma);
+
+	/* page should be within @vma mapping range */
+	VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
+
+	return address;
+}
+
 #else /* !CONFIG_MMU */
 static inline void clear_page_mlock(struct page *page) { }
 static inline void mlock_vma_page(struct page *page) { }