fput: turn "list_head delayed_fput_list" into llist_head

fput() and delayed_fput() can use llist and avoid the locking.

This is unlikely path, it is not that this change can improve
the performance, but this way the code looks simpler.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 834c9e5113d9..d40e8e78bbd1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -10,6 +10,7 @@
 #include <linux/stat.h>
 #include <linux/cache.h>
 #include <linux/list.h>
+#include <linux/llist.h>
 #include <linux/radix-tree.h>
 #include <linux/rbtree.h>
 #include <linux/init.h>
@@ -768,6 +769,7 @@ struct file {
 	 */
 	union {
 		struct list_head	fu_list;
+		struct llist_node	fu_llist;
 		struct rcu_head 	fu_rcuhead;
 	} f_u;
 	struct path		f_path;