3 files changed, 17 insertions, 9 deletions

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 0a97b583ee8d..e1474ae18c88 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -399,6 +399,18 @@ static inline struct page *read_mapping_page(struct address_space *mapping,
 }
 
 /*
+ * Get the offset in PAGE_SIZE.
+ * (TODO: hugepage should have ->index in PAGE_SIZE)
+ */
+static inline pgoff_t page_to_pgoff(struct page *page)
+{
+        if (unlikely(PageHeadHuge(page)))
+                return page->index << compound_order(page);
+        else
+                return page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
+}
+
+/*
  * Return byte-offset into filesystem object for page.
  */
 static inline loff_t page_offset(struct page *page)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index c6399e328931..7211a73ba14d 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -435,7 +435,7 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill,
         if (av == NULL) /* Not actually mapped anymore */
                 return;
 
-        pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
+        pgoff = page_to_pgoff(page);
         read_lock(&tasklist_lock);
         for_each_process (tsk) {
                 struct anon_vma_chain *vmac;
@@ -469,7 +469,7 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill,
         mutex_lock(&mapping->i_mmap_mutex);
         read_lock(&tasklist_lock);
         for_each_process(tsk) {
-                pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
+                pgoff_t pgoff = page_to_pgoff(page);
                 struct task_struct *t = task_early_kill(tsk, force_early);
 
                 if (!t)
diff --git a/mm/rmap.c b/mm/rmap.c
index b7e94ebbd09e..22a4a7699cdb 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -517,11 +517,7 @@ void page_unlock_anon_vma_read(struct anon_vma *anon_vma)
 static inline unsigned long
 __vma_address(struct page *page, struct vm_area_struct *vma)
 {
-        pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
-
-        if (unlikely(is_vm_hugetlb_page(vma)))
-                pgoff = page->index << huge_page_order(page_hstate(page));
-
+        pgoff_t pgoff = page_to_pgoff(page);
         return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
 }
 
@@ -1639,7 +1635,7 @@ static struct anon_vma *rmap_walk_anon_lock(struct page *page,
 static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc)
 {
         struct anon_vma *anon_vma;
-        pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
+        pgoff_t pgoff = page_to_pgoff(page);
         struct anon_vma_chain *avc;
         int ret = SWAP_AGAIN;
 
@@ -1680,7 +1676,7 @@ static int rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc)
 static int rmap_walk_file(struct page *page, struct rmap_walk_control *rwc)
 {
         struct address_space *mapping = page->mapping;
-        pgoff_t pgoff = page->index << compound_order(page);
+        pgoff_t pgoff = page_to_pgoff(page);
         struct vm_area_struct *vma;
         int ret = SWAP_AGAIN;