Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs fix from Al Viro:
 "Don't put symlink bodies in pagecache into highmem"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  Make sure that highmem pages are not added to symlink page cache

1 files changed, 5 insertions, 1 deletions

diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 0f88e6020487..f1b87d8aa2da 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -508,7 +508,11 @@ in your dentry operations instead.
 [mandatory]
         any symlink that might use page_follow_link_light/page_put_link() must
         have inode_nohighmem(inode) called before anything might start playing with
-        its pagecache.
+        its pagecache.  No highmem pages should end up in the pagecache of such
+        symlinks.  That includes any preseeding that might be done during symlink
+        creation.  __page_symlink() will honour the mapping gfp flags, so once
+        you've done inode_nohighmem() it's safe to use, but if you allocate and
+        insert the page manually, make sure to use the right gfp flags.
 --
 [mandatory]
         ->follow_link() is replaced with ->get_link(); same API, except that