Merge branch 'master' into for-3.9-async

To receive f56c3196f251012de9b3ebaff55732a9074fdaae ("async: fix
__lowest_in_progress()").

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 16 insertions, 5 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 32754eece63e..6001ee6347a9 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -574,19 +574,19 @@ static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj)
 
 	*hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj);
 	if (unlikely(!*hugepage_kobj)) {
-		printk(KERN_ERR "hugepage: failed kobject create\n");
+		printk(KERN_ERR "hugepage: failed to create transparent hugepage kobject\n");
 		return -ENOMEM;
 	}
 
 	err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group);
 	if (err) {
-		printk(KERN_ERR "hugepage: failed register hugeage group\n");
+		printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n");
 		goto delete_obj;
 	}
 
 	err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group);
 	if (err) {
-		printk(KERN_ERR "hugepage: failed register hugeage group\n");
+		printk(KERN_ERR "hugepage: failed to register transparent hugepage group\n");
 		goto remove_hp_group;
 	}
 
@@ -1819,9 +1819,19 @@ int split_huge_page(struct page *page)
 
 	BUG_ON(is_huge_zero_pfn(page_to_pfn(page)));
 	BUG_ON(!PageAnon(page));
-	anon_vma = page_lock_anon_vma_read(page);
+
+	/*
+	 * The caller does not necessarily hold an mmap_sem that would prevent
+	 * the anon_vma disappearing so we first we take a reference to it
+	 * and then lock the anon_vma for write. This is similar to
+	 * page_lock_anon_vma_read except the write lock is taken to serialise
+	 * against parallel split or collapse operations.
+	 */
+	anon_vma = page_get_anon_vma(page);
 	if (!anon_vma)
 		goto out;
+	anon_vma_lock_write(anon_vma);
+
 	ret = 0;
 	if (!PageCompound(page))
 		goto out_unlock;
@@ -1832,7 +1842,8 @@ int split_huge_page(struct page *page)
 
 	BUG_ON(PageCompound(page));
 out_unlock:
-	page_unlock_anon_vma_read(anon_vma);
+	anon_vma_unlock(anon_vma);
+	put_anon_vma(anon_vma);
 out:
 	return ret;
 }